In 1976, Brazil built its first bridgelayer, known as the XLP-10. The XLP-10 was based on a modernized Stuart hull, also known as an X1 hull, and carried a 10 m long bridge which could support up to 20 tonnes. Realizing that the capacity of this bridge was fairly limited as it would not be able to support the 83 M4 Shermans nor the 353 M41 Walker Bulldogs of the Brazilian tank fleet, the team behind the XLP-10 designed a bridge-layer based on the M4 Sherman chassis.
Due to the relatively limited number of Shermans in the country, none of the Sherman modernization attempts turned out to be a success. Brazil had figured that modernizing their 437 M3s was much less risky. and, by the time they had time to modernize a new vehicle, they had enough experience to modernize the M41, leaving the M4 to never receive any modernization. Although a few Shermans were converted into other prototypes, the XLP-20 never left the drawing board.
Bridging the First Gaps
The bridge-laying projects of the Brazilian Army seem to have started somewhere in between September 7th 1973 and September 29th 1974, with the first mock-up of a Stuart-based bridge-laying vehicle appearing on the later date. At the time, Brazil had initiated the X1 program to modernize its Stuarts to get more use out of them and to gain experience in modifying and building tanks. These programs were initially carried out with the companies Bernardini and Biselli, but Biselli stepped out of the defense industry around the mid-1970s.
The XLP-10 program started off with an electric bridge-laying design by the Instituto Militar de Engenharia (IME, Institute of Military Engineering), but at some point, the Instituto de Pesquisas e Desenvolvimento, (IPD, Research and Development Institute) authorized the Parque Regional de Motomecanização da 2a Região Militar (PqRMM/2, Regional Motomecanization Park of the 2nd Military Region) to develop its own bridge-laying design.
The PqRMM/2 was essentially the center where all the re-engining, modernisations, and new designs were developed and carried out. The PqRMM/2 was, for example, responsible for the re-engining of the M8 Greyhounds with diesel engines, the X1 tank program, and the development of what would become the EE-9 Cascavel. The PqRMM/2 came forward with a hydraulic bridge laying design and wrote up a report comparing it to the IMEs electric design.
Among the critiques were that the electric design from the IME was incapable of fully automatic bridge-laying, as the crew had to get out of the tank to manually couple or decouple the cables from the bridge. The design had an excessive height and the telescopic bridge-laying system was not functional, as it could not get low enough to lay the bridge over shallow river beds. The report was passed on to the Diretoria de Pesquisa e Ensino Técnico (DPET, Army Research and Technical Educational Board), which was the overarching military institution of the IME and the IPD, which decided to go for the hydraulic design to concentrate all the efforts into a single project.
The PqRMM/2 team and Bernardini delivered the first XLP-10 which was presented on the independence day parade of September 7th 1976. From there, 4 more XLP-10s were manufactured, which would all enter service in the early 1980s. It is thought that, after the success of the XLP-10 prototype in 1976, that the PqRMM/2 team started designing a similar bridge layer on a modernized M4 Sherman platform.
The Brazilian M4 Shermans
Brazil received 53 M4 Shermans through Lend-Lease during the Second World War. This is quite remarkable, as Brazil was the only South American country to receive Shermans through Lend-Lease, giving an idea to Brazil’s importance on the continent. This number would grow to a total of 83 Shermans after the country received an additional 30 Shermans through the Military Assistance Program (MAP). These Shermans consisted of standard M4s, early M4 composites, late M4 composites, and M4A1s. The main differences between the two composite types, known as CH-1 and CH-2 in Brazil, were the two hatch turret and the redesigned commander’s cupola for the late version, among other things.
By the late 1960s, many Brazilian vehicles required overhauling or modernisation, as the vehicles were over 25 years old. The M3 Stuart, in particular, received an extensive overhaul program known as Plano Impere (Empire Plan or Plan Empire). Brazil had a methodical approach to modernizing its vehicles. The PqRMM/2 team would begin with replacing the original engine with a locally produced and fully national diesel engine. This meant that Brazil attempted to fully transition its army to diesel fuel, although this would take until the 1990s to be carried out fully.
Among these initial re-engining projects was, of course, the M4 Sherman. Plans were drawn up as early as 1969 and the team opted for the MWM TD 232 V12 diesel engine. This engine could produce 406 hp, and on request from the PqRMM/2 (specifically the Centro de Pesquisa e Desenvolvimento de Blindados, CPDB, Center for the Research and Development of Tanks branch of the PqRMM/2 team), an aftercooler was installed which further increased the engines power to 500 hp. This would theoretically change the MWM TD 232 V12 into a MWM TBD 232 V12 engine instead, as the B specifically referred to a charge cooler or aftercooler for the turbocharger (D= standard diesel engine, TD Turbocharged, TBD Turbocharged and charge cooled).
Due to the limited number of M4 Shermans and them being overall more valuable than the M3 Stuart, the Sherman modernization was delayed in favor of modernizing the M3s. It would take until 1974 for the PqRMM/2 team to start replacing the engine and the project was completed and tested in 1975. After the tests were satisfactory, the company Biselli would switch out the older Vertical Volute Spring Suspension (VVSS) suspension with the newer Horizontal Volute Spring Suspension (HVSS, also known as the ‘E8’ suspension) from one of the three M74 recovery vehicles of the Brazilian Army. After this rebuild, the project was again put on hold in favor of the Stuart based projects.
The XLP-20’s Foundations
The M4 Sherman modernization was returned in 1977 in the form of a bridge-laying vehicle known as the XLP-20. The X stood for prototype, LP for Lançador de Ponte (Bridge Layer, literally Bridge Launcher), and the 20 for the length of its bridge, which was to be 20 m. The vehicle was to be designed by the IPD and Bernardini, with Bernardini acting as the manufacturer as well. The materials of the bridge were to be provided by the Brazilian subsidiary of the Canadian aluminum company Alcan. Supposedly, they also helped with the design of the bridge. It is possible that, due to the initial lack of knowledge in working with aluminum, Alcan would have also acted as the manufacturer of the bridges if the program went into production.
When exactly the design was initiated is unknown, but it might have been soon after the trials of the XLP-10 were completed and the 4 production vehicles were ordered, somewhere likely around late 1976 to some point in 1977.
The XLP-20 is in essence an upscaled and further developed XLP-10. It would make sense for the Brazilian Army to only initiate its development if the overall concept of the cantilever bridge laying method of the XLP-10 worked and met Army requirements. The XLP-20 was supposed to use a modernized Sherman chassis which could suggest that it would use the MWM V12 engine.
Interestingly, the design sketches show a VVSS suspension instead of a HVSS which was mounted on the latest iteration of the modernized Sherman. Supposedly, the Brazilians never made a copy of the HVSS suspension and would have to rely on importing them. Why Brazil never copied the HVSS suspension is unknown. Considering they copied the M3 Stuart, M4 Tractor, parts of the M4 suspension, and the M41 suspension, it would likely not have been beyond the capabilities of the Brazilian engineers.
The XLP-20 in Detail
The writer would want to put a disclaimer for the technical description of the XLP-20. Considering the design never left the drawing board, many specifications are simply unknown. The writer will attempt to work with the specifications which are either given, suggested or measured, but please note that these are estimations on what the XLP-20 would have looked like and functioned from a technical point of view.
The Sherman presented in the sketch is either an M4 or M4A1 Sherman. Considering Brazil had 36 M4 Shermans and only 2 M4A1s, the description will use the technical details of the M4 Sherman. The single biggest issue is represented by the dimensions of the bridge itself based on the technical drawing. When compared to the M4 or M4A1 Sherman, the lengths simply do not line up. The bridge’s potential lengths will be more thoroughly analysed in the bridge sub-section further on.
The M4 Sherman weighed about 30.3 tonnes in total, of which the turret itself weighed around 4.5 tonnes. Considering the turret would be removed and replaced with a bridge weighing around 8 to 9 tonnes, the XLP-20 would have weighed somewhere in the region of 35 tonnes. A campaign manual from the Brazilian Army lists an estimation of 34 tonnes.
The hull would be an estimated 5.89 m (19.3 feet) long, 2.62 m (8.6 feet) wide, and an unknown height. The height is difficult to determine due to the cantilever frame being hidden behind the bridge in the drawing. If a similar design style is considered as with the XLP-10, the cantilever frame would reach to about halfway the height of the bridge, giving a height of 2.5 m (8.2 feet) without bridge. The XLP-20 was about 18.5 to 20 m (60.7 to 65.6 feet) long, 3.5 m (11.5 feet) wide, and 2.9 m (9.5 feet) tall with the bridge. It would have likely had a two man crew, like the XLP-10, consisting of a driver, who could lay the bridge from his station, and the co-driver, who would assist the driver with laying or retrieving the bridge outside the vehicle if possible.
Hull and Armor
The hull would have essentially been that of a modernized Sherman. Considering only the engine changed, the armor protection should have been the same as on the M4 Sherman. The upper front and lower front plates would have been 51 mm (2 inch) thick. The sides and rear were 38 mm (1.5 inch), the top 19 mm (0.75 inch), and the floor 25 to 13 mm (1 to 0.5 inch).
If the XLP-20 would have had its hull machine gun removed like the XLP-10 is unknown. Considering this was done for the XLP-10 to facilitate a two hatch system for ease of leaving the vehicle for the co-driver and this style of hatch design would not have been possible on the M4 Sherman, it is a possibility that it would have retained the hull mounted .30 Cal (7.62 mm) Browning M1919 machine gun.
Like the XLP-10, the hull would have had two hydraulically powered pistons fixed on a pivot on the front which extended an outrigger to prevent the Sherman from tumbling over when laying the bridge. The foot of the outrigger would be connected to a rotating bar which would ensure that the foot would face the ground at full stroke. The interior of the vehicle would have housed certain components to enable laying the bridge, such as switches and the components for hydraulics. These could have included a hydraulics tank, a pump and the pistons for the cantilever system.
Mobility
The engine of the XLP-20 is unknown. Considering the re-engining of the Sherman a few years before the XLP-20 program, it is quite likely that, had those modernisations gone through for the Sherman fleet, the XLP-20 would have used the same engine. The main reason for this would be for logistical reasons in both components and usage of diesel fuel. The XLP-20 would thus have most likely had a turbocharged MWM TBD 232 V12 diesel engine with a likely power output of 500 hp. This would have given the XLP-20 a potential 14.3 hp/ton ratio compared to 16.5 hp/ton for a potentially modernized M4 Sherman. It would have used the same but possibly revised transmission as the original Sherman, with 5 gears forward and 1 in reverse. The top speed and range are unknown, but due to the increased mass of the tank, would have likely been less than the 34 km/h and the 160 to 192 km (100 to 120 miles) operational range of the standard M4 Shermans.
The XLP-20 would have used a VVSS suspension according to the design sketch. It would have had 6 road wheels divided over 3 bogies per track. Each bogie would also provide a single return roller on top, and the vehicle would have the drive sprocket at the front and the idler on the rear. The XLP-20 would have had an on ground track length of 384 cm (12.6 feet) and a track width of 42 cm (16.5 inches), giving the vehicle an estimated ground pressure of about 1.09 kg/cm2 (15.5 lbs/in2).
The Bridge
The dimensions of the bridge are debatable for a number of reasons. According to Expedito Carlos Stephani Bastos, the bridge was 20 m (65.6 feet) long, while according to Paulo Bastos, the bridge was 18.5 m (60.7 feet) long. The only sketch currently available does not provide any form of measurement and thus seems mainly to show how the concept would more or less have looked like with its main features. When using the M4 Sherman from the sketch as a basis, the bridge would be about 18.8 m (61.7 feet) long by using ratios to calculate the bridge length.
This seems to suggest that the claim from Paulo Bastos is more reliable, but keep in mind that the name of the vehicle is XLP-20 and the design sketch does not seem to have been focussed on specific dimensions. The possible dimensions of the bridge are displayed in the table below for each potential bridge length.
Bridge length
18.5 m (60.7 feet)
18.8 m (61.7 feet)
20 m (65.6 feet)
External width
3.5 m (11.5 feet)
3.5 m (11.5 feet)
3.75 m (12.3 feet)
Internal width
0.7 m (2.3 feet)
0.7 m (2.3 feet)
0.75 m (2.5 feet)
Lane width
1.4 m (4.6 feet)
1.4 m (4.6 feet)
1.5 m (4.9 feet)
Folding end length
2.75 m (9 feet)
2.8 m (9.2 feet)
3 m (9.8 feet)
Height
0.7 m (2.3 feet)
0.7 m (2.3 feet)
0.75 m (2.5 feet)
The bridge would have been made from aluminum and would have weighed around 9 tonnes. In contrast to the XLP-10, which had an internal width of 1.36 m, the XLP-20 would have likely not needed additional lanes to allow jeeps to cross the bridge, as the internal width of the XLP-20 would have been around 0.7 to 0.75 m. A requirement of the XLP-10 was that it could lay a bridge 0.3 m (1 foot) below ground level, which would likely have been maintained for the XLP-20. The bridge was to be laid and retracted in 5 minutes and was to carry vehicles of around 30 tonnes.
In essence, the bridge structure would have consisted of three main structures. The inner supporting structure and cantilever, which is known as the main frame, on which the bridge rested, would retract back and forth, and laid the bridge on the ground.
The second structure was the bridge itself. The bridge would have rested on top of wheels which were attached to the cantilever structure of the XLP-20. A C-shaped beam with a roller track was attached to both inner sides of the lanes. These tracks were driven by a hydraulic motor which drove the bridge forward and backwards through a sprocket.
The third structure were the folding ends. The folding end style bridge-layer seems to have been mainly inspired from the Soviet MTU-20 and MTU-72, which also use a cantilever and folding end system. The MTU bridge-layer folding ends function by having a bar connected to the foldable end, which is then connected to a hydraulic piston within the main bridge section. To fold open the bridge, the piston retracts and thus folds the bridge open by pulling the connecting rod inward. After the bridge is folded out, it is ready to be laid.
It is not completely certain how the system allows for ease of use for the hydraulic system inside the bridge itself for the foldable ends. It is thought that the bridge itself had quick-release connectors which would enable the bridge to be released from the hydraulic system without losing pressure in the hydraulic system of the bridge. It is also possible that the bridge was purely held in place by the folding sections locking into place, which would be unlocked when the bridge was retracted on the vehicle again through hydraulics, or it is a bit of both systems.
Since the bridge uses the exact same path for both laying and retraction, it would be possible to make the quick connectors at a fixed position so that the bridge can also fold in the ends when it is picked up again. The writer thinks that this concept would have likely been used on the XLP-20 as well if it was built.
The Hydraulics
The hydraulic system would essentially have powered 4 main components, which were the hydraulic motors for the bridge, the pistons of the cantilever, pistons for the folding ends, and the pistons of the outrigger, which prevented the XLP-20 from falling over. If the design concept of the XLP-10 was used for the XLP-20, then the hydraulic pump would be connected to the engine through gears and controlled from the inside by three levers. To protect the system, a solenoid valve with an electric sensor would have been added to prevent the activation of commands in the wrong order. The flow and pressure were regulated with valves and the hydraulic fluid was stored in a reservoir.
How the Bridge Got Laid
The process of laying the bridge would have essentially been exactly the same as for the XLP-10, but with an additional step, totalling 5. The XLP-20 would drive up to the gap and let the pistons of the outriggers fully extend in order to keep the vehicle in place. The folding ends would then be extended by the hydraulic pistons in the bridge frame. Then the bridge would be fully extended through the hydraulic engines. The cantilever pistons would then push the cantilever upwards and thus cause the bridge to be laid on the ground. Finally, the bridge was decoupled. The bridge would be picked up with the above mentioned process but reversed. This process would take about 5 minutes.
Fate and Conclusion
In the end, the XLP-20 never left the drawing board. It might have boiled down to simply being more worthwhile to invest in the M3 and the M41 modernisations instead because of the limited numbers of Shermans available. A number of attempts to modernize the M4 and other engineering concepts were attempted in the 1980s, but these failed to see success as well.
While converting most or perhaps even all of the Shermans into engineering vehicles could have been a fairly useful way to keep them in service, it would also mean that spare parts and logistics would have to be maintained for a vehicle type the Brazilian Army wanted to retire. Although it would take until 1988 for Brazil to officially retire the M3 Stuart and M4 Sherman, the process to stop using front transmission driven vehicles already started in the early to mid 1980s.
While the XLP-20 was not necessarily a bad idea to support regiments and brigades which had vehicles too heavy for the XLP-10, the number of M4 Shermans available in Brazil seems to have been the main limiting factor. It was simply more worthwhile to invest time and energy in M3 Stuarts and M41 Walker Bulldogs, which were available in large quantities. While it would not be the last attempt to find use for the old M4 Sherman, modernizing and then converting Shermans may have simply been more trouble than it was worth.
Illustration of the XLP-20 AVLB produced by Rolan Reboso, funded by our Patreon Campaign.
Specifications
Dimensions (L-W-H)
L: 20 – 18.5 m (65.6 – 60.6 ft) long w/ bridge, 5.89 m (19.3 ft) w/o
W: 3.5 – 3.75 m (11.5 – 12.3 ft) overall, 2.62 m (8.6 ft) hull only
H: Est. 2.9 m (9.5 ft) w/ bridge, 2.5 m (8.2 ft) w/o
Total weight
34-35 tonnes (37.5-38.6 US tons) w/ bridge, 25 tonnes (27.6 US tons) w/o
Crew
2 (driver & co-driver)
Propulsion
MWM TBD 232 V12 500 hp
Speed (road)
<34 km/h (<21 mph)
Armor
Front: 51 mm (2 in)
Sides: 38 mm (1.5 in)
Rear: 38 mm (1.5 in)
Top: 19 mm (0.75 in)
Floor: 25 to 13 mm (1 to 0.5 in)
Sources
Special thanks to Expedito Carlos Stephani Bastos, the leading expert of Brazilian armored vehicles (ecsbdefesa.com.br), Jose Antonio Valls, an Ex-Engesa employee and expert in Engesa vehicles, Paulo Bastos, another leading expert of Brazilian Armored vehicles and the author of the book on Brazilian Stuarts and the website (tecnodefesa.com.br), Adriano Santiago Garcia, a Captain in the Brazilian Army and ex-company commander on the Leopard 1 and ex-lecturer on the Brazilian Armored School, and Guilherme Travassus Silva, a Brazilian with whom I was able to endlessly discuss Brazilian Vehicles and who was always willing to listen to my near endless ability to talk about them.
Brazilian Stuart – M3, M3A1, X1, X1A2 and their Derivatives – Hélio Higuchi, Paulo Roberto Bastos Jr., Reginaldo Bacchi
Blindados no Brasil – Expedito Carlos Stephani Bastos
Lançador de Ponte XLP-10 – Expedito Carlos Stephani Bastos
Lançador de Ponte XLP-20 – Expedito Carlos Stephani Bastos
Jane’s Light Tanks and Armoured Cars of 1984
Worldwide Tank Fire-Control Systems – CIA www.lexicarbrasil.com.br
Personal correspondence with Expedito Carlos Stephani Bastos
Personal correspondence with Paulo Roberto Bastos Jr.
Caiafa Master
Engesa brochures and manuals
Cockerill brochures
TM 9-785 18-Ton High Speed Tractors M4, M4A1, M4C, and M4A1C – US Army April 1952.
Stuart: A history of the American Light Tank, Volume 1 – R.P. Hunnicutt
Tecnologia Militar Brasileira magazine
France/Federal Republic of Germany (1955?-1961)
Anti-Tank Reconnaissance Vehicle – 1 to 2 Prototypes Built
With the formation of the Bundeswehr in 1955, the new army of West Germany, a decision was made to acquire small tracked armored reconnaissance vehicles for use in the so-called Panzeraufklärungstruppe (Armored reconnaissance troop). The Schützenpanzer (Kurz), somewhat loosely translated as Infantry Fighting vehicle (Short), was born.
The Schützenpanzer was offered by the French company Hotchkiss-Brandt, which was unable to sell the design to the French in sufficient numbers due to budgetary constraints. The reconnaissance vehicle was offered as a family, ranging from infantry fighting vehicles to ambulances. Among the vehicles offered was a reconnaissance tank destroyer, which would be known as the Spähpanzer 1C (Reconnaissance tank 1C) or SP. 1C for short. This vehicle was interesting enough for the German staff to take the concept further and to let the German company Rheinmetall design a turret which matched German requirements. In the end, technical difficulties and the decreasing effectiveness of the chosen 90 mm gun caused the project to be closed.
The Founding of the Bundeswehr
Following the end of the Second World War, the defeated German Reich was divided into four occupation zones. As a result of the Potsdam Conference which took place from July to August 1945, France, Great Britain, and the United States occupied West Germany and the Soviet Union occupied East Germany. The four occupying powers decreed on August 30th, 1945, under Order no. 1, that the German Army was dissolved, with full dissolution of the armed forces under Law no. 8 on November 30th, 1945.
In the years following the occupation of Germany, a large string of events would open the door to German rearmament. The Cold War would slowly start as a result of the Soviet spread of communism through satellite states, the Truman Doctrine, the Berlin Blockade of 1948-1949, the detonation of the first Soviet atomic bomb, the formation of the separate West and East German states, the formation of NATO, the communist victory in the Chinese Civil War, and the Korean War from 1950 to 1953.
The Bundesrepublik Deutschland (Federal Republic of Germany, commonly known as West Germany) was founded on May 23rd, 1949. With the beginning of the Korean War a year later, a large group of ex-Wehrmacht officers met at the Himmerod Abbey to discuss the formation of a new West German Army. In 1951, the Bundesgrenzschutz (BGS) was formed as a lightly armed police force to patrol the West German border with the Soviet-aligned states.
Eventually, after a failed European Defence Community which attempted to put all the European Armies under a single overarching command structure, Germany was invited to NATO and joined on May 5th, 1955. On June 7th, 1955, the West German Federal Ministry of Defense was formed and, on November 12th, the Bundeswehr was created with the enlistment of its first 101 volunteers.
The Panzeraufklärungstruppe
With the formation of the Bundeswehr, a new reconnaissance force had to be rebuilt and reintegrated within the new West German Army units. NATO considered that a war with the Soviet Union would involve significant clashes of armored combat units. As a result, more divisions received an armored reconnaissance battalion, as they were integrated into Grenadier divisions as well. The expectation that the troops would have to fight for reconnaissance led to the integration of the M41 Walker Bulldog into the reconnaissance units.
The first Bundeswehr structure, in use from 1956 to 1958, called for 5 heavy reconnaissance squads with two M41s each, 11 light reconnaissance squads with 2 Bren Carriers each, a headquarters, and a supply company.
The second Bundeswehr structure, which was in use from 1959 to 1970, would initially struggle with what it actually wanted to achieve. The units were initially to receive 8 reconnaissance squads of 2 M41s each, 10 light reconnaissance squads with 2 SPz Kurz each, and 3 heavy squads were created, of which 2 received 2 M41s and 1 received an M41 and an IFV for radio. These new reconnaissance battalions and companies were so understrength that the units were not capable of performing combat missions according to a study of the Panzertruppenschule (Tank troop School).
By 1961, an additional heavy company was added to the understrength units, increasing the manpower of a reconnaissance battalion from about 287 men to almost 900. The increase was so significant that the reconnaissance battalions were on par with other battalions and were almost renamed to Panzerkavallerie-Bataillone (Armored Cavalry Battalions). The increase would cause the reconnaissance troops to be somewhat incorrectly deployed as either delaying or even offensive troops in practice maneuvers, besides their main reconnaissance tasks.
The 1961 restructure required a headquarters, 8 heavy squads with 2 M41s and 1 SPz Kurz each, 8 light squads with 2 SPz Kurz each, 2 infantry platoons with 9 SPz Kurz each, 2 armored platoons with 6 M41s each, a mortar platoon, and an Engineer platoon. The M41s would be replaced in 1965 by either the Leopard 1 or the M48 Patton after the Ru 251 light tank project had been canceled. The SPz Kurz would keep on serving into the third Bundeswehr structure until 1976, when it was replaced by the wheeled Luchs reconnaissance vehicle.
The Schützenpanzer (Kurz)
The story of the Schützenpanzer (Kurz), from now on called SPz Kurz, began all the way back in 1946. The French company SEAM came up with a general purpose light tracked vehicle for the French airborne troops. The French airborne troops would eventually request such a vehicle and the French Ministry of Defense transferred the requirements to DEFA for study. DEFA would contact SEAM, Hotchkiss, and AMX to come forward with a proposal and evaluated them on August 11th, 1947. The SEAM and Hotchkiss proposals were selected and the companies were contracted to build prototypes. Eventually, Hotchkiss was chosen as the winner. At some point, the protection requirements increased and the airdrop capability of the vehicles became less important.
Hotchkiss built prototypes of both cargo carriers and troop transport versions, known as CC 2-52 and TT 6-52 respectively. The vehicles were tested in France, North and South Africa, and the United States, after which the vehicle received favorable recommendations in 1952. A number of redesigns were incorporated, like a new Talbot/Hotchkiss engine instead of the original Ford engine. In total, the French ordered and built around 100 pre-series vehicles, but, due to the conflict in Indochina and later the Algerian War, full-scale mass production was unfeasible for the French Army.
This was where the newly founded Bundeswehr came in. The Germans were looking for a new vehicle to equip their reconnaissance units with and, in September 1955, the Cargo and APC versions were presented to the German Officials. The subsequent trials were promising enough for the Germans to order the Cargo version and to request 5 additional types to be designed. These were an Infantry fight vehicle, an 81 mm mortar carrier, an observation vehicle, a radar carrier, and an armored ambulance.
The combat weight of the vehicles was increased from 7 to 8.4 tonnes, the amount of road wheels was increased from 8 to 10, and the armor shape was redesigned. In practice, the vehicles were completely redesigned from the original basis to meet German requirements. Production began in 1958 with a total production run of 2,374 vehicles between 1958 and 1962, with the vehicle serving all the way up to the 1980s in the radar configuration.
The French SP. 1C
Supposedly, the SP. 1C was presented to the Germans somewhere in 1955 as a Spähpanzerjäger (reconnaissance tank hunter/destroyer), but the vehicle shown with the French turret was clearly altered for German requirements as it already had 10 road wheels. Thus, either the Germans were quite quick in handing over new requirements and the French then built adjusted prototypes in just 3 months, including a one-off tank destroyer variant which the Germans did not seem to have initially asked for, or the date provided in sourcing is incorrect.
The Jagdpanzer der Bundeswehr book claims that the German officials were presented with the tank destroyer vehicle in 1955, but that, after tests, it was determined that Rheinmetall should redesign the turret in 1957. It seems much more likely that the vehicle was actually built somewhere around 1956-1957 and then tested.
The French proposal was essentially a Schützenpanzer (Kurz) redesigned to accommodate the turret and the increased weight of the vehicle. The SP. 1C carried a H-90 like turret, closely resembling that of the AML-90. The vehicle had a height of 2.07 m, used a 90 mm DEFA D921 gun as main armament and an unspecified coaxial 7.5 mm machine gun. It carried 50 rounds of 90 mm and 2400 rounds of machine gun ammunition. The vehicle was crewed by the driver, a gunner, and a commander/loader. The main gun could fire a HEAT (High Explosive Anti-Tank) round with a penetration of 320 mm (12.6 inch) flat and a muzzle velocity of 800 m/s, granting an effective range of 1500 meters.
These changes resulted in the vehicle’s weight increasing from 8.2 to 9.5 tonnes (9 to 10.5 US tons). This, in turn, required an uprated engine to 195 hp to maintain a power to weight ratio of 20.5 hp/tonnes. The transmission was upgraded as well, from 4 speeds forward to 5. Supposedly, the tank destroyer version also came with neutral steering.
When the vehicle was shown to the German Army staff, they were quite enthused with the notion of offering their reconnaissance units greater anti-tank protection. It was thus a likely possibility that the German staff considered the SP. 1C as a replacement for the M41 Walker Bulldogs which were, at that point, to be used as reconnaissance tanks. It is also a possibility that they simply wanted to add or replace a vehicle with an SP. 1C in the Schützenpanzer units to strengthen the light reconnaissance squads or to field dedicated tank hunter squads complementary to the existing structure. In the end, the H-90 turret was too cramped for German requirements and, in 1957, Rheinmetall was ordered to design a turret of their own for the potential Spähpanzerjäger.
The German SP. 1C
Rheinmetall initiated the development of a new turret at the request of the Bundeswehr. The new turret incorporated a number of fundamental changes, most notably the Belgian 90 mm Mecar gun instead of the French 90 mm D921. Why this decision was made is unknown, but it is a possibility that the French simply refused to export their gun without exporting the turret as well. This was, for example, the case when the Brazilians wanted to import the guns for their X1 program, but ended up buying the entire turret as well, just to remount the guns into locally developed turrets.
The 90 mm Mecar was a bit of an odd gun. Very little is known about it and the gun only seems to appear on Swiss projects. After World War 2, the Swiss made an anti-tank gun known as the Pak 57, which seems to use the same muzzle brake and ammunition. It is a possibility that the Swiss bought a license from the Belgians or imported them and then started making their own anti-tank guns and arming vehicles with them. In any case, the Belgian 90 mm Mecar ended up on the SP. 1C as the main armament.
The Mecar gun was, without a doubt, worse all across the board compared to the French D921. It only had access to two types of ammunition at the time, HEAT and High Explosive (HE). It fired the ammunition at much slower muzzle velocities, reducing the effective range from 1.5 km (1640 yards) to 1 km (1090 yards) and making the gun less accurate. The penetration performance of the gun was also thought to have been worse, as the HEAT projectile weighed about 2.4 kg (5.3 lbs) compared to the 3.64 kg (8 lbs) of the French gun, but is listed in sourcing as having the same penetration.
The prototype turret was designed out of mild steel and sported a taller and more spacious shape. It also offered a much larger gun shield. This made the German vehicle 2.39 m (7.8 feet) tall compared to the French 2.07 m (6.8 feet), and increased the weight from 9.5 to 10.2 tonnes (10.5 to 11.2 US tons). The turret was designed with a multi-loading device. This meant that the turret would have some form of a magazine system, not to be confused with an autoloader. The vehicle was delivered for testing in 1961.
The multi-loading magazine system showed significant deficiencies and the gun used was already becoming outdated in the 1960s for the European theater. Due to the vehicle weighing 10.2 tonnes, which the drive train could handle, the suspension was on the edge of being overloaded. It is, however, interesting to note that the Koblenz museum lists the weight at 9.5 tonnes instead, while Rolf Hilmes lists it at 10.2 tonnes. It is unknown why this discrepancy exists, but considering the increased turret size, it is unlikely the weight stayed the same.
The overloaded suspension meant that no upgrade in armament could be carried out and that any weight increase would likely lead to intensive wear on the suspension system. The lack of armor and limited gun performance at range also meant that the vehicle could only properly carry out its tank destroying tasks from prepared ambushes, and would most likely be destroyed in any other scenario if it faced an armored opponent. Due to these deficiencies, the SP. 1C was rejected by the Bundeswehr and never entered service.
The SP. 1C in detail
Considering the range of specifications of the French SP. 1C and the German SP. 1C are quite similar, both will be included in the technical description. The French SP. 1C weighed 9.5 tonnes (10.5 US tons) and was 4.42 m (14.5 feet) long without the gun forward and 4.90 m (16 feet) with the gun included. It was 2.3 m (7.5 feet) wide and 2.07 m (6.8 feet) tall. The SP. 1C had a crew of three, consisting of the commander/loader (turret left), gunner (turret right), and the driver (front hull left side).
The German SP. 1C weighed 10.2 tonnes (11.2 US tons) (or 9.5 tonnes according to Koblenz) and, considering the caliber lengths of the Mecar and D921 gun were almost the same, would have likely had fairly similar length dimensions compared to the French vehicle. The width was also the same, but the height was increased to 2.39 m (7.8 feet). The German SP. 1C had a similar crew layout except that the gunner might also have been the commander instead of the commander also being the loader.
Hull
Both the French and German SP. 1C hulls were practically the same. The hull was armored with a 10 mm (0.4 inch) upper front plate inclined at 74° from vertical and a lower front plate of 15 mm (0.6 inch) inclined at 28° from vertical. The driver’s frontal plate with the bulge was 10 mm thick. The sides were 8 mm (0.3 inch) thick inclined at 23° from vertical, with the rear being 8 mm thick as well and an inclination ranging from 19° to 31° from vertical. The top was 15 mm thick and the floor ranged from 15 mm to 8 mm at the rear.
The SP. 1C had two sets of light blocks, one on each side of the upper front plate. These blocks included a headlight, a black-out light and an orange light (presumably turn signals). In between the light blocks was the gun lock with behind it a large removable plate to give access to the engine and transmission but also the driver’s compartment. In essence, the entire front plate could be taken off.
The driver’s position was clearly distinguished by the large bulge welded on the upper front plate. This bulge contained the mountings for three periscopes and a rotating sliding hatch for the driver. The driver steered with two tiller bars and had to manually shift gears. A fire extinguisher was located to the front right of the driver. The clutch pedal was located on the left, the brake on the right, and the accelerator pedal to the right of the brake pedal. The instrument panel was located to the left of the driver. The driver also had access to a floor hatch underneath the seat if needed.
The engine was located to the right of the driver. The engine air intake was located on the top hull on the front right. Behind the left light block was a siren and on either side of the upper front plate would have been side mirrors. At the front right side plate was the exhaust for the engine and behind it were belts to enable attachments of stowage. On the left side plates were attachments for pioneer tools.
The rear had two rear lights combined with turn signals on each side. The upper rear plate offered two hatches for unknown purposes. On top of one of the hatches was a stowage system for either spare tracks or perhaps the convoy driving cross. The lower front plate featured a towing hook.
Mobility
The SP. 1C was powered by a 195 hp Talbot/Hotchkiss 6-cylinder in-line petrol engine. This was effectively the same engine as on the original SPz Kürz, with the exception that the cylinders were bored out to increase the cylinder volume from 4.678 l to 4.977 l. This increased the horsepower from 164 to 195 and the torque from 324 to 353 Nm (238 ft lbs to 260 ft lbs). The engine was coupled to a 5 speed forward and 1 speed reverse transmission, in contrast to the 4 speed forward transmission of the standard vehicle.
Gear
Gear ratio
Speed at 3900 rpm
1
7.7
7.5 km/h
2
4.12
14 km/h
3
2.45
23.6 km/h
4
1.48
39.2 km/h
5
1
58 km/h
Reverse
7.1
8.3 km/h
This gave the vehicle a maximum speed of 58 km/h (36 mph) and 8.3 km/h (5.15 mph) in reverse. The power to weight ratio for the French variant would have been 20.5 hp/tonne and 19.1 hp/tonnes for the German SP. 1C. The vehicle had a 355 l (93 US gallons) fuel tank, of which 85 l (22.5 US gallons) was put away for reserves. This gave the vehicle an operational range of about 360 km (224 miles).
The SP. 1C used a torsion bar suspension with 5 road wheels on each side. The suspension system was reinforced to better handle the increased weight of the design on the French proposal. The suspension utilized shock absorbers and rubber stops to limit the travel of the suspension arms. The drive sprocket was located at the front and the idler wheel was at the rear. The total of 98 track links of each track were further supported by 3 guide wheels. The tracks were 308 mm (12.1 inch) wide and had a total on-ground track length of 2.38 m (7.8 feet). This gave the SP. 1C a ground pressure of 0.65 kg/cm2 for the French vehicle and 0.69 kg/cm2 for the German vehicle.
Turrets
The SP. 1C had two separate turrets available. One was an early form of the French H-90 turret which would be used on the AML-90 and the other was a turret developed by Rheinmetall at the request of the Bundeswehr. With the German turret also came a new main armament which seems to have been inferior to the French gun.
The reasons for choosing another main armament is unknown, but it can be noted that, when the Brazilians tried to buy 90 mm guns from the French in 1974, they had to buy both the turrets and guns in a single package. It is possible that this policy was already in place as early as the late 1950s, which forced the Germans to find a different gun.
The French Turret
The French turret was armored with 15 mm of welded steel plates at the front and had a decreasing thickness of 15 to 10 mm on the side from front to rear. The rear had a thickness of 10 mm and the top had a thickness of 8 mm. This armor would provide protection against small caliber rounds.
The commander/loader, positioned on the left side of the turret, had 4 periscopes available and the gunner on the right as well, with a single main firing periscope available in front of him totaling to 5 periscopes. It is unclear if the gunner had access to an emergency direct fire telescope fixed to the right of the main gun, in the gun mantlet. In the middle of the turret top, behind the commander and gunner hatches, was the outlet for the ventilation system. The coaxial machine gun was located on the left side of the main gun. The antenna of the radio was located behind the gunner and attached to the rear side plate. Two smoke launchers were mounted on each of the rear of the turret side plates, for a total of four.
It is unknown how far the interior of this early H-90 turret was similar to the H-90 production turret. As such, the following information is provided in case the layout was almost exactly the same. The turret stored 24 rounds of 90 mm ammunition, of which 12 rounds on the left side of the turret bustle and another 12 rounds in two 6 round-revolver style magazines behind the gunner and the commander. The turrets stored 2,400 rounds (12 boxes) for the 7.5 mm coaxial machine gun, of which at least 9 were stored in a magazine in the frontal part of the turret basket floor. The turret had a gun depression of -8° and an elevation of +15°.
The German turret
The German turret developed by Rheinmetall was manufactured out of mild steel, as opposed to armor grade steel. The German turret has a reasonable amount of unknown details. Some of this has been a result of the lack of interior picture of the turret or lack of measurements. As the Koblenz Museum, where the SP. 1C is preserved, is still closed, this information cannot yet be obtained.
The armor was likely somewhat similar to the French turret and is not thought to have offered more than protection against small arms. Interestingly, Rolf Hilmes claims the armor of the German SP. 1C was 20 mm, which could refer to the thickness of the gun shield. This could have theoretically barely provided the front with protection against .50 cal machine gun fire.
The German turret was octagonal shaped and welded. The vehicle had a distinct gun shield with a direct fire telescope on the right side of the gun and the coaxial machine gun to the left. On both sides of the gun shield were two protrusions with small sliding hatches, the purpose of which is unknown. The gunner, located on the right, had 4 periscopes and what seems to be a main telescope for the main gun on the right of the front periscope.
The commander/loader on the left only had two periscopes pointing to the side of the vehicle. This seems strange and might suggest that, in the German turret, the gunner was also the commander and the loader only had loading duties, in contrast to the French layout. Both crew men had relatively small hatches. The middle of the turret top was occupied by a very large plate. It seems that the purpose of this plate was to help facilitate the magazine loading system of the main gun. If the gun was depressed past a certain point, the magazine system would move upwards to still accommodate loading the gun. This moving plate was located from the gun shield to the rear of the turret and had hinge attachments on the front. The turret had a gun depression of -8° and an elevation of +15°.
The two rear side plates had three smoke launchers each and the rear plate had two smoke launchers and an antenna attachment. The rear plate also had a small brass plate with the writing: Turm 2 Sp Kurz, Flußstahlausführing, Rh.-Nr.WK-G2 (Turret 2 Sp Short, mild steel version, Rh.-Nr.WK-G2). This could suggest that Rheinmetall developed two turrets or that the initial French turret was considered as turret 1.
Nothing is known of the turret interior. It is assumed that a very large portion of the turret interior would be occupied by the magazine loading system of the vehicle. According to the information sign in front of the SP. 1C at Koblenz, the magazine loading system could house an astonishing 18 main rounds. Sadly, as pictures are non-existent, this cannot be confirmed visually, nor is it known if the prototype even retained its magazine loading system to begin with.
Armament
The SP. 1C used both the French 90 mm D921 and the Belgian 90 mm Mecar gun. Of these guns, the French gun was both superior in performance and ammunition load-out. The Mecar gun only offered High Explosive Anti-Tank (HEAT) and High Explosive (HE) ammunition. The French gun could also fire smoke and canister ammunition.
90 mm D921
Round
Capability
Effective range
Velocity
HEAT (High Explosive Anti-Tank)
320 mm (12.6 inch) flat at any range.
1,500 meters (1,640 yards)
750 m/s
HE (High Explosive)
Lethal radius of 15 meters (16 yards)
1,500 meters (1,640 yards)
650 m/s
White Phosphorus – Smoke
50 meters wide smoke screen for 20 to 30 seconds
1,500 meters (1,640 yards)
750 m/s
HEAT-TP (High Explosive Anti-Tank – Training Projectile)
Inert (no explosive filling)
1,500 meters (1,640 yards)
750 m/s
The Belgian gun was inferior performance wise in both muzzle velocity and effective range. The Belgian HEAT round only had a muzzle velocity of 630 m/s against 750 m/s of the French gun. This made the Mecar gun less accurate and gave it an effective range of 1200 m (1,310 yards) opposed to 1500 m (1,640 yards). The HE round was even more problematic due to the 338 m/s muzzle velocity, opposed to the French 650 m/s.
90 mm Mecar
Round
Capability
Effective range
Velocity
HEAT (High Explosive Anti-Tank)
320 mm (12.6 inch) flat at any range.
1,200 meters (1,310 yards)
630 m/s
HE (High Explosive)
Lethal radius of 15 meters (16 yards)
–
338 m/s
The French vehicle had a total of 50 rounds of 90 mm ammunition, of which an estimated 24 could be found in the turret, while the German version was said to stow around 40, of which potentially 18 in the magazine loading system. The French SP. 1C also came with a 7.5 mm machine gun as opposed to the MG 42 for the German variant.
Fate
In the end, the SP. 1C’s already overloaded chassis was bound to cause reliability issues in any long term operation of the vehicle. The main armament’s suitability was falling off rapidly by the 1960s against increasingly heavy Soviet material. The magazine loading system, which was perhaps the vehicle’s only redeeming factor, also proved to have been lacking during tests. This system was perhaps one of the few features which could have made the SP. 1C deadly in ambushes due to the potentially rapid loading times. As such, the SP. 1C could only effectively contribute to the anti-armor capability of the reconnaissance troops from covered positions in an ambush. For these reasons, the SP. 1C was rejected by the Bundeswehr and the prototype remains at the Koblenz Tank Museum.
A Mystery
While researching the SP. 1C, the writer found a picture of a vehicle on a Quora thread which suspiciously looks like some form of SP. 1C. The turret seems to be a much lower profile variant of the current turret and overall much more simplified. The turret almost seems like a mock-up or a home-built. It is unclear if this turret was perhaps the turret 1 prototype from Rheinmetall or just a hobby construction. Any information regarding the vehicle’s origin and owner would be much appreciated.
Conclusion
The SP. 1C was an interesting yet faulty concept. Had the vehicle been developed much earlier and perhaps not as a weapon against the increasingly heavily armored Soviet tanks, the results might have been different. The SP. 1C simply pushed the boundaries of its own capabilities too far and with technical systems that proved to be faulty. By the 1960s, it also became clear that the Leopard 1 would be replacing the M41 Walker Bulldogs in the reconnaissance units, which had a much higher fighting chance against its Soviet counterparts. The SP. 1C remains as an interesting light tank and an attempt to take the SPz Kurz family full circle by offering a dedicated anti-tank vehicle.
Specifications
French SP. 1C
German SP. 1C
Dimensions (L-W-H)
4.9 x 2.3 x 2.07 m (16 x 7.5 x 6.8 ft)
4.9 x 2.3 x 2.39 m (16 x 7.5 x 7.8 ft)
Total weight, battle-ready
9.5 tonnes (10.5 US tons)
10.2 tonnes (11.2 US tons)
Crew
3 (driver, gunner, commander/loader)
3 (driver, commander?/gunner, loader)
Engine
Talbot/Hotchkiss 6-cylinder in-line 195 hp petrol
Talbot/Hotchkiss 6-cylinder in-line 195 hp petrol
Speed
58 km/h ( mph)
58 km/h ( mph)
Range
360 km ( mi)
360 km ( mi)
Power to weight ratio
20.5 hp/tonne
19.1 hp/tonne
Suspension
Torsion bar
Torsion bar
Transmission gearing
5 forward – 1 reverse
5 forward – 1 reverse
Fuel capacity
355 l (93 US gallons)
355 l (93 US gallons)
Armament
Primary: 90 mm DEFA D921
Coaxial: 1 x 7,5 mm
Primary: 90 mm Mecar
Coaxial: 1 x 7.62 mm MG42
Elevation and traverse
15° elevation 8° depression
15° elevation 8° depression
Ammunition capacity
50
Around 40
Armor
Hull:
15 mm lower front plate
10 mm upper front plate
8 mm sides and rear
Turret:
15 to 10 mm
Hull:
15 mm lower front plate
10 mm upper front plate
8 mm sides and rear
Federative Republic of Brazil (1985)
Wheeled Reconnaissance Vehicle – 1 Built
In 1984, Engesa initiated the development of an APFSDS (Armor Piercing Fin Stabilized Discarding Sabot) round for the low pressure 90 mm gun of the EE-9. Why exactly Engesa entered such an endeavor is unknown, as kinetic energy projectiles are usually not viable for low pressure guns. Nevertheless, the round was developed and would offer a wider range of ammunition for their customers and make it look like the EE-9, now reaching 10 years of service, was still keeping up with modern developments of its time.
Developing an APFSDS round did not come without its challenges, however. Issues like the muzzle brake, a rifled barrel, materials and manufacturing processes had to be resolved. The culmination of the project seems to have taken place in July 1985, when an EE-9 fitted with a pepperpot-type muzzle brake was presented to an Iraqi delegation. This may suggest an Iraqi influence or interest in the APFSDS round, but sadly, the Iraqis did not end up acquiring the APFSDS round and the project was, for all intents and purposes, abandoned.
The EE-9 and Iraq
The story of why the EE-9 Cascavel (English: Rattlesnake) was developed can be traced back to the Second World War. Brazil sent an expeditionary force, known as the ‘Smoking Snakes’, to fight in Italy alongside the Allies. During the Italian campaign, the Brazilian forces were equipped with the 6-wheeled M8 Greyhound armored car. The Greyhound turned into a beloved vehicle for the Brazilian soldiers for its armor, simplicity and mobility, and after WW2, this love would remain embedded in the Brazilian Army.
Although Brazil enjoyed its diplomatic relations with the United States well into the 1970s, the first steps to break free from the United States, from an army materiel point of view, started in 1967. The United States had become increasingly involved with the Vietnam War and, as a result, could not supply Brazil with the cheap equipment it once did. As such, it was decided that the Brazilian Army would instead try to develop their own armored vehicles.
One of these was the EE-9 Cascavel, which was passed on to Engesa for production after the Army had developed a number of prototypes. The EE-9 was a 6 x 6 wheeled vehicle initially armed with a 37 mm, but would be armed with a 90 mm on suggestion of the Portuguese. While being the spiritual successor of the M8 Greyhound, two of the main innovations of the EE-9 were the usage of the boomerang suspension, which enabled it to cross much more difficult terrain ,and the incorporation of bimetallic armor, which offered improved protection over homogenous steel. Engesa managed to secure an export deal with Libya for 200 EE-9s in 1974 and, soon after, would receive an order for an additional 200 vehicles. From there, the EE-9 became Engesa’s flagship product, as they would sell it to multiple South American countries as well.
The use of the EE-9 Cascavel by Libya and its export success managed to get the attention of Iraq. After three weeks of negotiations, Engesa managed to secure the export contract for 364 EE-9s and 148 EE-11s on May 5th 1978. Iraq would be the first to receive a new model of EE-9, known as the EE-9 M4. In contrast to previous models, the EE-9 M4 used an MT-643 transmission which could handle the more powerful Detroit Diesel 6V53 212 hp engine. In addition, the hull featured a number of redesigns, like the integration of the headlights in the lower hull plate instead of the installation on top of the upper front plate. The most significant change was the redesigned ET-90 turret, known as ET-90 II, which was able to incorporate night vision sights.
A New Generation of Ammunition
Engesa was known for developing a wide range of concepts or options to market to potential customers. Some of these developments were fairly reasonable, while others just seem to have been developed for the sake of making a product and perhaps even the company looking more impressive. The EE-11 Urutu, effectively an EE-9 turned into an armored personnel carrier, was the prime subject for receiving all kinds of variants which tended to not generate any sales, but were extremely simple and cheap to manufacture nonetheless.
The development of the new EE-9 APFSDS (Armor Piercing Fin Stabilized Discarding Sabot) and canister (a round filled with steel balls) rounds may have been such a project according to an ex-Engesa employee, but could also have had some Iraqi influence as well. In 1984, the Engesa subsidiary Engequímica was founded, which was tasked with both the manufacture of all Engesa’s ammunition and the development of the new generation of EE-9 ammunition. The writer will refer to Engequímica for the development side of the ammunition while for the marketing and overarching business side the writer will refer to Engesa instead.
Considering the EE-9 was still very much the flagship product of Engesa, it is quite likely the company decided to make the gun seem more modern and appealing by offering an APFSDS round. While APFSDS was not a new concept, it had started to generate much more interest by the late 1970s, with NATO countries shifting from APDS (Armor Piercing Discarding Sabot) to APFSDS for both their 105 mm and 120 mm armament. The French also developed a wide range of APFSDS rounds for their high pressure 90 mm F4 guns, which would be mounted on the Brazilian Tamoyo 1 tank, and even some gun-mortars. At the time, Bernardini had also started to take steps by copying and subsequently manufacturing the French APFSDS round of the 90 mm F4 for the Tamoyo program.
Additionally, the Iraqi Army was thought to have requested the development of a canister round for the EE-9 Cascavel somewhere in 1984, as it was embroiled in the Iran-Iraq war at the time. At a similar time, General Amer Rashid had also requested the development of an anti-air EE-9 and it could be that he requested the development of the new ammunition as well. Why exactly the Iraqis sought a canister round for the EE-9 is unknown. It was likely that the canister round was requested to make the EE-9 better equipped against dealing with infantry formations. The Engequímica team developing the round called it the Cartucheira Gigante or Giant Cartridge in English. When the round was fired, it could sweep everything in a cone of about 20 meters (22 yards) wide at a distance 100 meters (109 yards) away, basically functioning like a giant shotgun. In the end, both the APFSDS and canister rounds were presented to an Iraqi delegation.
The canister round weighed 6.2 kg in total and was filled with 1,400 steel balls. Each ball had a diameter of 6 mm (0.25 inch) and weighed 0.88 grams for a total of 1.23 kg of balls inside the round. The effective range of the round was said to have been 150 to 200 meters (164 to 219 yards) and the muzzle velocity was around 520 m/s. Interestingly, Iraq supposedly also requested for the development of a longer range shrapnel round, which seems to appear in an Engesa brochure. Here, the shrapnel round had a muzzle velocity of 600 m/s and an effective range of 700 meters (765 yards). The maximum range was 800 meters (875 yards) with a dispersion of 1 mil (1 meter at 1,000 meters). In contrast to the canister round, which would function like a shotgun, the shrapnel round would detonate at a certain range and act like a large grenade.
The EC-90 Gun
Initially in 1974, Engesa sold the EE-9 Cascavel with the H-90 turret and the 90 mm D921 gun from the French, which was initially used on the AML-90. While preferring to only acquire the guns, the French only sold the gun and turret in a single package. As such, Bolivia, Chile and Libya received the French package. This was fairly advantageous for Engesa, as the AML-90 was widely available to their customer base and crews would need little retraining to serve in an EE-9.
As 284 EE-9s with the French turret were sold, the French caught on to the competitive challenge the vehicle could have on their own export market. As a result, the French raised the turret prices to such an amount that Engesa had no choice but to look for a different option. They found their solution with the Belgian company Cockerill and the EC-90 gun.
The EC-90 90 mm gun was a license production from the Cockerill Mk.3. Engesa acquired the license to produce the low-pressure 90 mm Cockerill 90 Mk. 3 gun in 1975 for US$3 million (US$15.5 million in 2021). The gun would be designated EC-90 by Engesa, with the E standing for Engesa, C for Canhão (Cannon), and 90 for the 90 mm gun. This license deal not only made it possible for Engesa to manufacture their own guns, but it also opened the door for them to design their own turrets. Additionally, due to the incorporation of the bimetallic steel armor, these turrets were also better protected than the French counterparts.
Low Pressure APFSDS?
Developing an APFSDS round for the EC-90 gun did come with a number of issues -the biggest being the very nature of the gun. The EC-90 was a so-called low pressure gun. This meant that the gun used low muzzle velocities which allowed larger caliber guns to be installed on extremely light platforms, such as the 5.5 tonne AML-90 or even a Toyota Technical. The use of low muzzle velocities entailed that traditional kinetic energy (K.E.) based anti-tank rounds, like AP and APDS, became unfeasible, as they relied on high muzzle velocities and thus high pressures for penetration performance.
This issue was circumvented by the usage of chemical energy (C.E.) ammunition, known as HEAT (High Explosive anti-Tank) and HESH (High Explosive Squash Head) ammunition. Chemical energy ammunition takes its penetration performance from the chemical charges inside the ammunition. As such, chemical energy ammunition performance was mostly bound by gun diameter rather than muzzle velocity. This meant that a HEAT round would have the same penetration at point blank as at 1,000 meters (1094 yards), as the potential penetration energy stored inside the round remained the same. Higher muzzle velocities mainly had influence on the accuracy and maximum effective range of the HEAT rounds.
This made low velocity 90 mm guns extremely dangerous, as the HEAT round of the French D921 could penetrate around 320 mm (12.6 inches) of flat steel armor at any range, while the Cockerill and EC-90 could penetrate around 250 mm (10 inches) of flat steel armor at any range as well. The difference in performance had to do with the French expertise in the development of HEAT ammunition. In just a few years, light reconnaissance platforms which previously were lightly armed and posed little threat to main battle tanks could theoretically destroy tanks like the T-55 family and the M48 Patton, even when engaging them frontally.
With the introduction of APFSDS, this performance gap between kinetic and chemical energy ammunition on low pressure guns became more equal. As APFSDS did not require spin stabilization, both the Length to Diameter ratio (L/D ratio), and velocity could be increased, boosting penetration performance. This change over the older AP and APDS rounds made the use of a kinetic energy round in the form of APFSDS more practical from low pressure guns.
The APFSDS round would still be somewhat inferior in penetration performance compared to a HEAT round for the 90 mm low pressure guns, but the gap was closed. The APFSDS round which was developed on the EE-9 was rated to penetrate a NATO single medium plate at 1,100 meters (1,200 yards), or 130 mm (5.1 inches) at 60° at 1,100 meters. Interestingly however, a later APFSDS round from Cockerill with fairly similar specifications is only rated in Cockerill’s brochures as 100 mm (4 inches) at 60° at 1,000 meters. Although there is variation as to exactly how these tests were conducted, it seems logical to assume that the APFSDS round of Engesa penetrated anywhere from 100 to 130 mm at 60° at 1,000 meters. Comparatively, this is marginally worse than the HEAT round, which is rated at 130 mm at 60° at any range.
It is also interesting to note that Engesa marketed the APFSDS round not as being a better round than the HEAT round in penetration performance, but in terms of the hit probability. The APFSDS boasted a higher but still relatively low muzzle velocity of 1,175 m/s, compared to the 890 m/s of the HEAT ammunition. However, the velocity increase and the much smaller projectile meant that accuracy of the APFSDS round at 1,000 meters was doubled from 0.8 mils (0.8 meters at 1,000 meters) dispersion of the HEAT round to 0.4 mils (0.4 meters at 1,000 meters). Additionally, the effective range doubled as well from 1,000 m to 2,000 m and the maximum range increased from 2,100 m to 3,000 m. Effectively, the APFSDS round offered a more accurate round at the price of only a small reduction in penetration which could still pose a theoretical threat to tanks like the T-55 family and the M48 Patton.
Development and Testing
Development of the APFSDS round started at an unknown date, but due to the dates available on later images and Engesa’s tendency to quickly design and develop new equipment, it is thought development started in 1984. At this point, Engesa would have had some experience in the role of APFSDS in armored vehicle design with the EE-T1 Osorio tank project which started in 1982. Additionally, the Brazilian subsidiary Engequímica, which designed the ammunition, was founded in 1984.
Engequímica designed a saddle/spool type APFSDS round in accordance with NATO style APFSDS rounds of the time period. The engineers supposedly considered both steel and tungsten for the penetrator, but went with the more capable tungsten in the end. This would be essential, considering the penetration gap to be bridged between the APFSDS and HEAT rounds for the APFSDS to be a viable option.
The tungsten penetrator had a 16:1 L/D ratio, with a diameter of 20.2 mm (0.8 inches) and a length of about 323 mm (12.7 inches). The penetrator and sabot combined weighed 2.9 kg and the sabot itself 1.8 kg. The sabot was most likely made from aluminum, like most other sabots were, making up about 38% of the projectile launch weight. The sabot weight was on the heavier side of the spectrum, as sabots tended to weigh about 30 to 39% of the total projectile launch weight at the time.
As previously mentioned, development likely started in 1984, and an image dated in October at an unknown year may suggest that live firing trials with the new round were initiated around that period. This is because later images of testing appeared in May 1985 and the testbed appeared in July 1985. Considering no APFSDS acquisition was requested after the testbed was presented, it is assumed that further development of the APFSDS round was canceled. This is further supported by an ex-Engesa employee noting that they never fixed some of the design issues, suggesting that the development was shelved as no interest was shown.
A Matter of Muzzle Brakes
The image of testing in October also excellently illustrates one of the main issues of APFSDS ammunition for light weight platforms. In the image, the standard triple baffle muzzle brake was placed on the ground and a so-called pepper pot muzzle brake was mounted on the gun instead. Complicated multi-stage muzzle brakes tend to interfere with the proper separation effect of the sabot, as the sabot would start to separate prematurely inside the muzzle brake.
Ex-Engesa employee Edson Kiyohara, assigned to the Engequímica program, noted that they tested the APFSDS rounds on both muzzle brakes to see if the triple baffle muzzle brake could be used. According to him, Engequímica first tested the standard Cascavel muzzle brake, but that the muzzle brake was damaged by the sabot separating inside.
As a result, Engequímica switched to the much simpler pepper pot muzzle brake, which is not much more than a steel tube with holes drilled into it to redirect the propellant. Since the pepperpot effectively acted as an elongation of the gun barrel, the sabot would not separate in the muzzle brake, as it would not get the required space to split. However, due to its simple nature, the effectiveness of limiting the gun recoil force was reduced compared to the standard muzzle brake. As a result, premature wear or a less comfortable vehicle for the crew to be in while firing the gun would be the compromise. Additionally, the increased trunnion pull force would also mean that the gun became less suitable for lighter vehicles, although this was less of a problem for the EE-9.
Had the APFSDS round for the EE-9 actually caught on, it would not be surprising if Engequímica would have switched to the single baffle muzzle brake, as on the French guns, of which the 90 mm F4/CN90 BR3 on the Tamoyo 1 tank was an excellent example. Supposedly, these muzzle brakes were more effective than the simple pepper pot muzzle brakes. Eventually, Engequímica could also have taken inspiration for a more advanced pepperpot design as on the B1 Centauro, as Engequímica would use the same 105 mm OTO-Melara gun on the EE-18 Sucuri tank destroyer.
Further Testing
Further testing of the APFSDS round itself seems to have been carried out in May 1985, as multiple images appear of the gun and the round at the Marambaia testing grounds. The tests included penetration tests and sabot separation tests, according to an Engesa/Engequímica employee present.
The sabot separation tests seem to have not been much more than a mesh fixed to a wooden frame at which the APFSDS round was fired. The goal of the test was to see if the sabot separated more or less equally and this could be tested to by observing if the distances between the projectile in the middle and the three sabot spreads was more or less equal. In the image available, the APFSDS round fired showed a satisfactory sabot spread.
The penetration tests were essentially firing the APFSDS round at a target consisting of a number of spaced steel plates. The gun was mounted in a static gun mount which was positioned 250 meters away from the steel plates. Each steel plate was 25 mm thick and placed vertically with a gap of 25 mm of air in between each plate. This would dampen the kinetic energy and blunt the APFSDS round as it would be subjected to various impact shocks while going through the plates. As a result, the APFSDS round managed to penetrate just 2 plates during this test.
Interestingly, this test seems to undercut Engesa’s brochure claim that the APFSDS round could penetrate a triple medium NATO target at point blank range. For a triple medium target, the round would have to penetrate a 10 mm, a 25 mm and finally a 60 mm plate. Considering the 25 mm plate penetration tests were done at 250 m on a 90 mm gun, this would have been the equivalent of a point blank test.
The claim that the APFSDS round could penetrate a NATO single Medium target was not, however, impossible. The previously mentioned similar Cockerill round was rated to be able to defeat 100 mm of steel armor at 60° at 1,000 m. Considering NATO penetration standards required 50% of the rounds to go through to rate it at a penetration, it would not be unfeasible if Engesa simply listed the higher potential estimate to make the round look more appealing on paper.
Presentation of the EE-9 APFSDS Testbed
In July 1985, an Iraqi delegation visited the Marambaia proving grounds to receive a presentation of the various projects which Engesa was carrying out for Iraq and other countries at the time. Among the vehicles presented were the prototype ET-25 armed Cascavel on the standard hull, the EE-9 with the pepper pot muzzle brake for the APFSDS test batch, and the EE-T1 P0 Osorio mock-up.
The vehicles were shown and some test firing was carried out. It does seem that Iraq had no real interest in the APFSDS round, as no further images of the EE-9 with the pepper pot muzzle brake seem to have appeared and the APFSDS round development never got further than the initial test batches. It is quite likely that the lack of interest of the Iraqi delegation in the round would have caused further development of the round to have been shelved until a customer showed serious interest in acquiring it again.
EE-9 M4 APFSDS Testbed in Detail
The EE-9 M4 APFSDS testbed weighed around 12.5 tonnes (13.8 US tons) combat-loaded. It was an estimated 6.3 m (20.7 feet) long including the gun and 5.25 m (17.2 feet) without the gun. It was 2.59 m (8.5 feet) wide, about 2.29 m (7.5 feet) tall to the top of the turret and 2.6 m (10.5 feet) tall to the top of the ET-7.62 commander’s cupola. The EE-9 M4 had a crew of three, consisting of the commander/loader (turret left), gunner (turret right), and the driver in the middle front hull.
Hull
The hull of the EE-9 M4 was manufactured from welded bimetallic steel plates. The hull also featured two covers which were mounted on the hull above the Boomerang suspension, effectively functioning as mudguards and very minor spaced armor. These mudguards could also have recesses in the middle, as on the Iraqi EE-9 M4s, to stow additional jerrycans.
The front upper hull plate presented 16 mm (0.63 inches) of bimetal armor at an angle of 60º. The sides and rear were 8.5 mm (0.33 inches) thick at varying angles, and the top and bottom hull were 6.5 mm (0.26 inches) thick. The front of the EE-9 was meant to protect from .50 caliber machine gun fire at an unknown range, while the entire vehicle was protected from 7.62 mm AP rounds at 100 m (109 yards), and standard 7.62 mm rounds at 50 m (54 yards).
The average effectiveness of the bimetallic plates was about 1.8 times the thickness of an equivalent homogeneous plate against 7.62 mm or 1.5 times the thickness against .50 caliber machine gun fire. This meant that, against .50 caliber machine gun fire, a 16 mm bimetallic plate could be used instead of a 25 mm homogenous steel plate. These protection advantages over homogenous plates effectively meant that the Cascavel saved a lot of weight without compromising protection. The outer layer would shatter and blunt the incoming projectile, while the inner layer would relatively move with the bullet, slowing it down and stopping it without shattering.
The EE-9 M4 had two headlights and black-out lights integrated in both sides of the lower front plate. A rearview mirror could be mounted on both sides of the upper front plate. Below the driver’s vision block was a foldable windshield, which the driver could use when driving with an open hatch. The driver had access to 3 periscopic sights mounted in a sort of vision block in front of him. The driver’s rotating sliding hatch was part of the top plate and was located behind the vision blocks. These periscopes and other periscopes or sights would not have been active or passive night vision equipment unless the Cascavel was ordered with these devices. The standard periscopes were manufactured by D.F. Vasconcellos.
A ventilation inlet was installed on both upper hull side plates. These ventilation inlets are recognizable by their frustum shape. A siren was installed behind the ventilation inlet on the right side of the vehicle. The fuel tank cap of the Cascavel was located on the left side, in the middle of the upper side hull plate, with the fuel tank installed on the hull floor. The EE-9 had a large ventilation grille on the rear of the vehicle, reminiscent of the M8 Greyhound, and had a rear light on both sides of the ventilation grill. The engine could be accessed through two large hatches on the hull top rear. The engine exhaust was located on the top right rear plate, as was unique to the EE-9 M4s.
The M4 used an adjustable ZF 8062 hydraulic powered steering wheel and had two pedals: the throttle on the right side of the steering wheel, and the brake to the right of the throttle. The gear selector was located to the right of the driver and the hand brake was located to the left. A control panel was located on the front left of the driver for, among other things, the headlamps, siren, windshield, the various meters, and interior lighting. To the right was the pressure selector for the central tyre inflation system.
Mobility
The EE-9 M4 used the Detroit Diesel 6V53N V6 engine, which produced 212 hp at 2,800 rpm and 598 Nm at 1,800 rpm. The engine had a total cylinder capacity of 5.212 liters, with a cylinder diameter of 98 mm and a stroke of 114 mm. The M4 Cascavel had a top speed of 95-100 km/h (59 mph) and an operational range of 750 km (466 miles).
It had a turning radius of 8.12 m (8.88 yards) and it could ford a depth of 1 m (3.3 feet) without additional preparation. The Cascavel could climb a 65º slope, could climb a vertical obstacle of 0.60 m (2 feet), cross a 1.65 m (5.4 feet) trench, and had a ground clearance of about 0.5 m (1.6 feet). The front-wheel could travel for 0.2 m (0.66 feet), while the rear wheels could travel for 0.9 m (3 feet). It used 12 x 20 run-flat tires which were 0.5 m (1.6 feet) wide. The EE-9 M2 had a distance between the front axle and rear axle of 3.05 m (10 feet), and a distance of 1.4 m (4.6 feet) between the two rear wheels.
The EE-9 M4 used an automatic Detroit Allison MT-643 transmission with four forward and one reverse gears. The transmission system could handle up to 250 hp and was the only transmission used in the EE-9s which could mount the Detroit 6V53 engine. The M7s would also use this transmission, but they were never paired with a Detroit when they were sold by Engesa.
In addition, the Cascavel used an Engesa 2 speed transfer case, which allowed the Cascavel to be used in reduced and high gear. By putting the Cascavel in reduced gear, horsepower was sacrificed for increased torque, making it more effective in climbing slopes. The vehicle was 6 x 6 driven, of which the rear 4 wheels were part of the Boomerang suspension. The Boomerang suspension, in combination with the Engesa 2 speed transfer case, enabled the Cascavel to cross challenging terrain and provide maximum traction in most situations.
The power of the engine was distributed to a differential on the front side of the vehicle, and a differential in the rear. The rear differential drove the Boomerang suspension with a single axle, which made the Boomerang suspension such an ingenious design.
In 1969, this suspension was invented by Engesa to enable trucks to transport oil to the refineries through rough terrain with bad infrastructure. With this suspension, the trucks could traverse otherwise untraversable hills for conventional suspension systems, as the wheels would always stay in contact with the ground to provide maximum traction.
The suspension system was a two wheeled-single axle driven suspension. The advantage of the Boomerang suspension was that it could be fitted on existing differentials with a single axle. Normally, this meant that the single axle, designed for the torsion forces of a single wheel, was subjected to the torsion forces of two wheels. Through excellent engineering, half of the torsion forces of the two wheels were mitigated by the suspension system built around the original axle. This design not only enabled the drive of two wheels by a single axle but, with clever usage of gears and bearings on both the axle and tube around the axle, the suspension system can rotate around its axle for 360º. This ability to rotate in extreme angles would enable the vehicles to traverse very difficult terrains and still provide maximum traction, as the suspension system curved with the terrain so that all the wheels were always in contact with the ground.
The Boomerang suspension used leaf springs for dampening. The two front wheels were used for steering. The wheels on the Boomerang suspension all rotated at the same speed. The front wheels were dampened by large coil springs. The vehicle used hydraulic disc brakes, and was steered with hydraulics as well.
A Central Tyre Inflation System (CTIS) came standard with the M4s. This system would help in obtaining the appropriate traction at various speeds by regulating the tyre pressure. This could help in crossing rough terrain but also save fuel. This was done by the driver through a switch. A Bendix Tu-flo 500 air compressor was used to provide the air flow and pressure for the CTIS.
Turret
The EE-9 APFSDS testbed used an all-welded bimetallic steel construction to protect against small arms fire. The ET-90 II turret had 16 mm of armor at the front and 8 mm of armor at the sides, rear, and top. The turret had a hatch for the commander/loader on the left and the gunner on the right. The commander’s position could also incorporate the ET-7,62 commander’s cupola. The turret had access to a pistol port on the left side to remove spent casings from the turret, and 3 smoke launchers on each side rear of the turret. Additionally, the turret was provided with 4 lifting hooks, an illumination lamp at the front and a stowage rack on the rear.
The ET-7,62 commander’s cupola was armored with 8 mm bimetal steel plates angled at 15° from vertical minimum and had a 680 mm diameter turret ring. It mounted a gun mount for a 7.62 mm machine gun, although the EE-9 APFSDS used an ET-50 gun mount for a .50 caliber machine gun instead. This seems fairly characteristic for the Iraqis at the time, who were said to have a preference for using heavy machine guns against helicopter ambushes of the Iranians during the Iraq-Iran war. The machine guns could be fired remotely from the inside and were provided with a reticule in the sight, but also a simple steel ring in front of the middle sight. The cupola had access to 5 sights, of which the middle front sight could use an SS-130 day-night sight. The SS-130 sight was an image intensifier sight with no magnification. The commander also had access to two periscopes on the front sides, and direct vision sights on the rear sides. The commander used a manual drive to rotate the cupola.
The gunner was located on the right and had access to a day/night sight for the main gun. This was an SS-122 sight on the Cascavels, an image intensifier sight which provided 10x magnification for the day sight and 9x for the passive night vision channel. The sight mirrors were coupled to the main armament to allow for automatic elevation of the sight mirrors in accordance with the gun elevation.
The commander was also the loader of the vehicle, having 12 rounds located in the turret bustle on the left side and 12 rounds in two 6-round revolver style magazines behind both the gunner and commander/loader. He had 8 boxes of machine gun ammunition in front of him and another box to his rear. The coaxial machine gun was located to the left of the gun, in front of the commander/loader and also housed a box of ammunition, for a total of 11 boxes when including the machine gun on the commander’s cupola.
The electronics, like intercoms, control boxes for the sights and switches were located to the right of the gunner, while the radios were located in the turret bustle. The SS-122 sight was in front of him, with a control box for a laser rangefinder to his front left. As the EE-9 APFSDS testbed did not mount a laser rangefinder on top of the gun, it is unclear if the control box was in the vehicle. It is likely that Engesa did not mount it, as the vehicle was only used for test firing at a range with the distances already known. The gunner had access to 3 more periscopes, of which 2 were located on the side of the turret and 1 to the rear of the gunner. The gunner used manual drives to elevate the gun and to rotate the turret. Although Engesa did market an electric drive system, it is unknown if this system was ever sold to any country.
Armament
The EE-9 APFSDS testbed used a modified EC-90 III cannon as its main armament. The EC-90 was a licensed production of the 90 mm Cockerill Mk.3 gun, obtained in 1975, and was 36 calibers long. This resulted in a barrel length of 3.24 meters (10.6 feet) excluding the muzzle brake. As the muzzle brake was replaced with a less efficient one to enable the use of APFSDS, it was quite likely that the recoil force increased as a result. It would have been possible to increase the gun recoil stroke from the standard 500 mm to 530 mm (19.7 inches to 20.9 inches) to help mitigate the inefficiency of a pepperpot muzzle brake design.
EE-9 M4 APFSDS testbed ammunition
Round
Capability
Maximum range
Velocity
APFSDS (Armored Piercing Fin Stabilized Discarding Sabot)
100 to 130 mm at 60° from vertical at 1,100 meters.
3,000 meters (3,280 yards)
1,175 m/s
HEAT – NR 478A1 (High Explosive Anti-Tank)
250 mm-300 mm (9.8-11.8 inches) flat at any range and 130 mm at 60° from vertical at any range.
2,000 meters (2,185 yards)
890 m/s
HESH – NR 503A2 (High Explosive Squash Head)
Meant for bunkers, walls and light vehicles.
2,000 meters (2,185 yards)
800 m/s
HE – NR 501A1 (High Explosive)
Lethal radius of 15 meters (16 yards)
1,600 meters (1,750 yards)
700 m/s
White Phosphorus – Smoke – NR 502A2
50 meter wide smoke screen for 20 to 30 seconds
1,600 meters (1,750 yards)
695 m/s
HEAT-TP – NR 479A2 (High Explosive Anti-Tank – Training Projectile)
Inert (no explosive filling)
2,000 meters (2,185 yards)
750 m/s
The firing table and the ‘crosshair’ of the direct-fire telescope for the EC-90 gun went up to 3,000 m for the HEAT round, 2,380 m for the HE and smoke round, and 1,020 m for the coaxial machine gun. The main armament was fired with a pedal on the turret basket floor and could be cut off through the main electrical system box. This box controlled things such as the ability to fire the main and coaxial armament, configure the ventilation system, and internal lights. In some EE-9s, the firing table was added as a plate on the electrical system box as well. The electrical system box was mounted to the right of the gunner. Additional control boxes would be added for equipment such as laser rangefinders and day/night sights if needed.
The ET-90 II turret of the APFSDS testbed used a 7.62 mm FN MAG M971 machine gun as its coaxial armament and had a .50 caliber machine gun mount on the ET-7.62 commander’s cupola. In theory, the M971 could fire up to 1,000 rounds per minute, while the practical rate of fire was about 600 rounds per minute. Its maximum practical range was 1,200 m and it weighed 2.8 kg. The coaxial machine gun was installed on the commander’s side, as the commander acted as the loader, but was fired by the gunner through a button on the main gun’s elevation handle. It could be manually fired by the commander if needed. The gun had an elevation of 15° and a depression of -8°. The EE-9 carried 2,200 rounds of 7.62 ammunition, divided between 11 cases, and a total of 44 rounds for the main gun, of which 20 were stored in the hull and 24 in the turret.
Cancellation and Unsolved Issues
When the APFSDS round development was exactly canceled is unknown. Considering the Iraqis did not seem to take interest in it in July 1985, it is quite likely the APFSDS round development was canceled soon after, as they would be Engesa’s most likely buyer for the APFSDS. It is also a possibility that the Iraqis did not have the money to acquire such a niche round as, from 1985 on, the Iraqi finances started to gradually run out due to the Iraq-Iran War. According to one of the engineers who worked on the project, a number of issues with the APFSDS round were never resolved.
The rifled gun posed a number of challenges for the APFSDS round to work properly, as the round was not supposed to spin when leaving the barrel. The rifling meant that pressure had to be limited, but it also damaged the so-called nylon obturator ring holding the sabot together and supposedly the sealing ring. Another challenge was finding out the proper depth for the so-called buttress threading on which the sabot is placed to allow it being forced through the barrel by the pressure, but also split when the projectile leaves the barrel. When machined too shallow, the sabot would not split, but when machined too deeply, the sabot would split too early in the barrel. The engineer was convinced they could have fixed these issues, had the project not been canceled. Additionally, it would be quite likely that, had the project gone through, Engesa would have offered a more efficient muzzle brake design than the pepperpot.
Why exactly the project was canceled is unknown as well, but a number of indicators point towards multiple reasons on why a customer would prefer to stick with the HEAT ammunition instead. The first is that the APFSDS round does not offer any penetration performance advantage over the HEAT round. It was more accurate and offered a better effective range, but it can be questioned how much the increased effective range would actually be utilized, as the penetration performance would drop further as well. Additionally, and perhaps the main reason, the APFSDS round would have cost about US$630 each, compared to about US$460 for the HEAT round. This meant that a customer would be paying US$170 more for a less versatile and worse performing round for a little increased accuracy and range, of which the latter may or may not be used too much.
While Engesa never seems to have considered this, it would have perhaps been a better idea if it had started offering a more anti-tank focused gun instead for the EE-9. These could have been the 60 mm HVMS, although this gun lacked the ammunition versatility of the EC-90, or, perhaps more competitively, the 90 mm F4. The 90 mm F4 was a high pressure and high velocity gun which was already in Brazil in 1984, as it was mounted on the Tamoyo 1 in 1984. The 90 mm F4 was also mounted on the French ERC-90 Sagaie 6×6 wheeled vehicle, which meant that the EE-9 could have directly competed with it. In essence, the 90 mm F4 used the same ammo as on the French 90 mm D921, but also introduced an APFSDS round. As such, Engesa could have simply refitted their existing projectiles for his gun as well, but with modified casings.
However, from a different point of view, most of the larger Sagaie sales already happened at the turn from the 70s to the 80s and only about 20 were sold after 1984. Additionally, the Sagaies could be sold with much more advanced systems, like stabilization, a linked fire control system, a semi-autoloader, and electro-hydraulic turret drives. The EE-9 would either have to be sold with a similar fire control system or be sold as a cheap and simple upgunned competitor instead.
The fate of the EE-9 M4 APFSDS testbed is unknown. It is likely that it remained as a test vehicle for Engesa with the pepperpot muzzle brake removed, but its fate after Engesa’s bankruptcy is unknown. It was likely either sold to one of the legacy companies, like Universal or Columbus, scrapped, or potentially sold to Iraq in the last batch of EE-9s sold in 1985. A number of Engesa vehicles, like both Osorio tanks and the EE-3 Jararacas, would initially end up with the 13th RCMec in Pirassununga, but this does not seem to have happened with the testbed.
Conclusion
In the end, the costs of the APFSDS round for the EE-9 simply outweighed the minor benefits it brought to the table. The performance was lacking and the price tag did not justify the increased accuracy and extended range compared to the HEAT ammunition. It would have perhaps been more effective if Engesa had decided to offer a more dedicated anti-tank version, although this would have been a much more expensive vehicle with perhaps a very limited market. An APFSDS shooting EE-9 ended up as a dead end.
Specifications (EE-9 M4 ET-25)
Dimensions (L-W-H)
6.3 x 2.59 x 2.29 m (20.7 x 8.5 x 7.5 feet)
Total weight
12.5 tonnes (13.8 US tons)
Crew
3 (driver, commander, gunner)
Propulsion
Detroit Diesel 6V53 212 hp engine (or OM352A 172 hp engine)
Speed (road)
95-100 km/h (59 mph)
Operational range
750 km (466 miles)
Armament
90 mm KBA cannon
7.62 mm FN MAG (coaxial)
Optional .50 machine gun (turret top)
Armor
Hull Bimetal
Front 16 mm (0.63 inches)
Side 8 mm (0.32 inches)
Rear 8 mm (0.32 inches)
Top 6.5 mm (0.26 inches)
Floor 6.5 mm (0.26 inches) ET-25 turret (Estimated)
Front 16 mm (0.63 inches)
Side 8 mm (0.32 inches)
Rear 8 mm (0.32 inches)
Top 8 mm (0.32 inches)
Produced
1
Special thanks to Expedito Carlos Stephani Bastos, the leading expert of Brazilian armored vehicles https://ecsbdefesa.com.br/, Jose Antonio Valls, an Ex-Engesa employee and expert in Engesa vehicles, Paulo Bastos, another leading expert of Brazilian Armored vehicles and the author of the book on Brazilian Stuarts and the website https://tecnodefesa.com.br, Adriano Santiago Garcia, a Captain in the Brazilian Army and ex-company commander on the Leopard 1 and ex-lecturer on the Brazilian Armored School, and Guilherme Travassus Silva, a Brazilian with whom I was able to endlessly discuss Brazilian Vehicles and who was always willing to listen to my near endless ability to talk about them.
Sources
Engesa EE-9 Cascavel 40 anos de combates 1977-2017 – Expedito Carlos Stephani Bastos
Brazilian Engesa EE-9 Cascavel 6×6 at war 1977-2020 – Expedito Carlos Stephani Bastos Blindados no Brasil – Expedito Carlos Stephani Bastos
Engesa manuals
Engesa brochures
Dual Harness skin stops armor-piercing projectiles Article of Richard M. Ogórkiewicz Technology of Tanks – Richard M. Ogórkiewicz
Personal correspondence with Ex-Engesa Employees
Personal correspondence with Expedito Carlos Stephani Bastos
Personal correspondence with Paulo Roberto Bastos Jr.
Federative Republic of Brazil (1985)
Wheeled Anti-Aircraft Vehicle – 1 Built
As the Iraq-Iran War was raging on, Iraq was searching for anything which might be able to swing the conflict in its favor. To accomplish this, Iraq sought help from a rising powerhouse in the defense export world to help bring this advantage. The rising Brazilian defense industry had interesting and functional concepts, but most importantly, Iraq could buy its loyalty and heavily fund the industry for it to develop new equipment fully catering to Iraqi requirements.
One of these projects was to fill the requirement of a wheeled anti-aircraft screening vehicle to help cover the Iraqi convoys from Iranian helicopter attacks. Iraqi Army officials contacted the Brazilian company Engesa, which had previously delivered 364 EE-9 Cascavels and 148 EE-11 Urutus, to suggest that the Iraqi Army would be willing to acquire such a vehicle if the company could develop a suitable solution.
As such, Engesa went to work. The company decided that developing a 25 mm autocannon armed turret to be mounted on the EE-9 Cascavel was the way forward, and so, the EE-9 with ET-25 turret was born.
The EE-9 and Iraq
The story of why the EE-9 Cascavel (English: Rattlesnake) was developed can be traced back to the Second World War. Brazil sent an expeditionary force, known as the ‘Smoking Snakes’, to fight in Italy alongside the Allies. During the Italian campaign, the Brazilian forces were armed with the M8 Greyhound. The Greyhound turned into the most loved vehicle by the Brazilian soldiers, and after WW2, this love would remain embedded in the Brazilian Army.
Although Brazil enjoyed its diplomatic relations with the United States well into the 1970s, the first steps to break free from the United States, from an army materiel point of view, started in 1967. The United States got increasingly involved with the Vietnam War and, as a result, could not supply Brazil with the cheap equipment it once did. As such, it was decided that the Army would try to develop their own armored vehicles.
One of these was the EE-9 Cascavel, which was passed on to Engesa for production after the Army had developed a number of prototypes. Engesa managed to secure an export deal with Libya for 200 EE-9s in 1974 and soon after would receive an order for an additional 200 vehicles. From there, the EE-9 became Engesa’s flagship product, as they would sell it to multiple South American countries as well.
The usage of the EE-9 Cascavel by Libya and its export success managed to get the attention of Iraq. After three weeks of negotiations, Engesa managed to secure the export contract for 364 EE-9s and 148 EE-11s on May 5th 1978. Iraq would be the first to receive a new model of EE-9, known as the EE-9 M4. In contrast to previous models, the EE-9 M4 used an MT-643 transmission which could handle the more powerful Detroit Diesel 6V53 212 hp engine. In addition, the hull featured a number of redesigns like the integration of the headlights in the lower hull plate instead of the installation on top of the upper front plate. The most significant change was the redesigned ET-90 turret, known as ET-90 II, which was able to incorporate night vision sights.
This deal started the arms relations between the two countries for the next 13 years. This relation would eventually morph into Iraq becoming virtually the most important customer for the Brazilian defense industry. The start of the Iraq-Iran War in 1980 and the subsequent stalemate would catapult the Brazilian defense industry into its golden age. Systems like the successful ASTROS rocket launcher, the Piranha air-to-air missile, and the EE-T4 Ogum were mostly funded and specifically built to cater to the Iraqi market. An EE-9 for anti-air purposes was also requested by the Iraqi Army.
The Anti-Aircraft Cascavel
The Iraq-Iran War saw the most intensive use of helicopters of any conventional war up to that point. Early on, Iraqi tank convoys were attacked and successfully destroyed through the use of TOW and Maverick air-to-surface missile armed AH-1J helicopters. In order to protect these convoys from so-called pop-up attacks, the Iraqi Army sought a vehicle which could act as an anti-helicopter screen and that could immediately engage an enemy helicopter when the convoy was ambushed or when it encountered it. As such, infantry dismounts with surface-to-air missiles and especially expensive and vulnerable surface-to-air missile systems which needed time to be deployed were less suitable for this role.
The requirements and request for the development of such a screening vehicle were supposedly passed on to Engesa by General Amer Rashid at an unknown date. Considering Engesa’s ability to develop prototypes very rapidly (the EE-T4 Ogum prototype was developed and built in just 6 months), it is quite likely that this request was made somewhere in late-1984 to early-1985. In any case, Engesa went to work.
How the development process exactly went is unknown. It is likely that Engesa looked at the platforms they had available, which were in service with the Iraqi Army, and which were suitable to receive such a role. Engesa likely selected the EE-9 to be used for the anti-aircraft concept as it already drove alongside the armored columns. The Cascavels were used as reconnaissance vehicles and thus were already used to screen the armored columns against potential ground targets. An anti-aircraft EE-9 could still be used in a similar way for reconnaissance but with the emphasis laying on air targets instead.
Turret Designations
Before going into the turrets designed for the 25 mm armed Cascavel, it is perhaps useful to clarify a number of things regarding designation. As far as is known, two ET-25 turrets were made. The first seems to have been converted from the pre-existing ET-90 II turret of the standard EE-9. The second was an actual ET-25 turret which was designed from the ground up.
Normally, as with the ET-90 turrets, the first could be designated ET-25 I and the second ET-25 II. Since there is no documentation regarding how Engesa itself designated the turrets, the first turret will be designated in this article as the ET-25 prototype. The second turret will simply be designated ET-25.
Developing the ET-25 Turret
According to earlier sourcing from the Brazilian armored vehicle expert Expedito Carlos Stephani Bastos, the very first prototype turret built by Engesa was suspiciously identical in every way to the T 25 turret from OTO Melara. While there is the extremely remote possibility that Engesa copied the T 25 turret, it seems extremely unlikely. The turret also does not fit the more functional and simplistic design style of the company either. As such, it is very unlikely that this turret was built by Engesa, which seems to be supported by the fact that the turret is omitted from later works of Expedito Carlos Stephani Bastos.
There is still a possibility that the T 25 turret influenced the ET-25 turret from Engesa instead. The interior layout seemed to be somewhat similar and the overall shape in the later design stages of the ET-25 turret started to resemble a more functional and simplified version of the T 25. In the early stages, however, Engesa quite simply seemed to have taken the ET-90 turret and adapted it to be armed with the Oerlikon 25 mm KBA autocannon.
A cut-out depression on the right side of the turret was made to facilitate a shell case ejection system, like on the T 25. What does stand out is that while the turret seems to be based on the ET-90 II turret, it does differ in hatch opening concept. From the ET-90 II on, the crew hatch of, for example, the gunner hinged open toward the front, protecting the front of his body when leaving the vehicle. The initial ET-25 prototype turret had both the hatches for the gunner and commander open towards the rear, like in the older ET-90 I design.
It is interesting to note that the Osorio composite armor variant was developed through the use of an Oerlikon 25 mm autocannon as well. Scale models of the composite armor package were tested by shooting at them with the autocannon to simulate the impact 105 and 120 mm tank rounds at the CTA (Centro Técnico Aeroespacial, Aerospace Technical Center). When this was carried out is unknown, but it seems to have been done before 1985, as the CEO of Engesa claims the composite armor was ready in an interview in 1985. As such, it is a possibility that the 25 mm autocannon used to test the Osorio composite is the same 25 mm which ended up arming the ET-25 turret, as it was already in the country and had no other use. This lines up timetable wise, as the first testing of the ET-25 prototype turret was carried out in April 1985.
The EE-9 with the ET-25 Prototype
The first picture of an EE-9 mounting a prototype ET-25 turret was taken in April 1985 at the Marambaia proving grounds. According to the ex-Engesa employee Edson Kiyohara, the turret was ready and tested as well at that moment. What is perhaps even more interesting than the ET-25, is the EE-9 it was mounted on. The EE-9 shown in the picture is perhaps the single rarest EE-9 Cascavel to have existed, as it uses wheel hubs with planetary gears.
No EE-9 in service ever used such a system and it only ended up being used on the EE-11 M7 Urutu versions. The advantage of such systems is that they have much better power and torque transmission efficiencies over conventional designs. Drive shafts suffer only a third of the torque over conventional systems as well.
In July 1985, the turret was mounted on a standard EE-9 M4 hull. An EE-9 M4 can be distinguished from the other EE-9s due to the engine exhaust being located on the top right rear plate. Only Detroit powered EE-9s had this exhaust placement style and only M4s are known to have mounted Detroit 6V53 engines. While EE-9 M7s could mount such an engine as well due to them also having an MT-643 transmission, they seemingly were never acquired with them. The likely reasons for this ranged from pre-existing logistical structures to increased costs of about US$20,000 per vehicle, with less capital heavy customers being the main buyers of the EE-9 M7.
The July 1985 Iraqi Delegation
In July 1985, an Iraqi delegation visited the Marambaia proving grounds to receive a presentation of the various projects which Engesa was carrying out for Iraq and other countries at the time. Among the vehicles presented were the prototype ET-25 armed Cascavel on the standard hull, an EE-9 with a pepper pot muzzle brake for the APFSDS test batch, and the EE-T1 P0 Osorio mock-up.
The vehicles were shown and some test firing was carried out. The concept was something of a success, as Engesa started designing a brand new 25 mm armed turret from the ground up. It would not be unsurprising if the converted ET-90 turret was a proof of concept to gauge the Iraqi interest in a 25 mm armed Cascavel.
Redesigned ET-25
With the seeming enthusiasm secured from the Iraqi delegation, Engesa set off developing a new turret. The turret was smaller in shape and more in line with what was needed to house the 25 mm gun. The turret bustle was reduced in size, as it did not need to store 90 mm ammunition as on the ET-90. and the front tapered off much more heavily due to the much smaller breach of the 25 mm. In addition, a round commander’s cupola was introduced for the commander to have better vision around the vehicle and a searchlight was introduced on the front left side of the turret.
While the turret was more in line with the needed size to house the 25 mm gun, it was just 50 kg lighter, at 2200 kg, than the ET-90 turret, which weighed 2250 kg. This most likely had to do with the introduction of electric turret drives. As far as is known, no ET-90 turret ever received electric turret drives when they were sold by Engesa. The turret drives would have been heavy and above all, they cost as much as the entire turret itself. For the ET-25 however, electric turret drives were a must to help the crew in dealing with more nimble and faster helicopters.
It is interesting to note that an ex-Engesa employee recalls that the ET-25 turret was a manual turret. According to Jane’s Armour and Artillery, this seems to not be the case, as the ET-25 turret came standard with the electric turret drives. It is, however, possible that the employee referred to the prototype ET-25 turret instead, which does seem to have been a repurposed ET-90 II turret.
From here on, the timeline starts to get hazy. This mainly has to do with a single picture of the EE-9 with the new ET-25 turret being tested in Iraq with an Iraqi paint scheme. This hull could be the same hull as the one with the prototype ET-25, but an ex-Engesa employee remembered that the turret was tested on one of the Iraqi hulls. This last detail of the ex-Engesa employee may hold the potential clue in the timeline.
The course of events seems to have gone as follows. An Iraqi commission visited the Engesa factory in September 1986. During this visit, led by Minister of Military Affairs General Abdul Jabbar Shanshal, the founder of Engesa, José Luiz Whitaker Ribeiro, showed the EE-9 ET-25 to the Iraqi general. The vehicle was presented in a brown and dark green camouflage with the EE-T1 P2 Osorio presented behind the vehicle.
After that, in February 1987, it was presented at the Engesa facilities to a Kuwaiti delegation. Why Kuwait was interested in the vehicle is unknown. The turret was dismounted from the hull but still retained the brown and dark green camouflage. Afterwards, the turret seems to have been sent to Iraq for final trials, where it was mounted on an EE-9 M4 hull from Iraq. It failed to garner enough interest and was sent back to Brazil.
A 30 mm armed ET-25?
While researching the EE-9 ET-25, the writer found a number of mistakes in previous sourcing. The Italian turret was one of these, while the other error was a supposed 30 mm armed ET-25. According to Expedito Carlos Stephani Bastos, the new ET-25 turret was armed with a 30 mm gun. Multiple ex-Engesa employees refute this claim however, of which one was present when the delegation from Kuwait came to visit the turret.
In addition, the Jane’s Armour and Artillery book also presented the ET-25 turret and never mentioned an optional possibility to mount a 30 mm autocannon. This would be strange if the 30 mm was actually built as Engesa was known to offer as many options as possible to cater to potential customers. As such, it is very unlikely that a 30 mm armed ET-25 was ever built.
EE-9 ET-25 in Detail
As the EE-9 ET-25 was meant for Iraq and was actually mounted on an EE-9 M4 hull, the writer will write the technical section based on the EE-9 M4 specifications. This does not, however. mean that the ET-25 turret would have been exclusively offered on EE-9 M4 hulls.
The EE-9 ET-25 weighed around 12.5 tonnes (13.8 US tons) combat-loaded. It was an estimated 5.3 m (17.4 feet) long including the gun, as the muzzle brake seems to slightly extend further than the hull, and 5.25 m (17.2 feet) without the gun. It was 2.59 m (8.5 feet) wide, about 2.57 m (8.4 feet) tall to the top of the turret and about 3.2 m (10.5 feet) tall if the ET-50 .50 caliber machine gun mount was counted as well. The EE-9 ET-25 had a crew of three, consisting of the commander/loader (turret left), gunner (turret right), and the driver in the middle front hull.
Hull
The hull of the EE-9 M4 was manufactured from welded bimetal steel plates. The hull also featured two covers which were mounted on the hull above the Boomerang suspension, effectively functioning as mudguards and very minor spaced armor. These mudguards could also have depressions in the middle, as on the Iraqi EE-9 M4s, to stow additional jerrycans.
The front upper hull plate presented 16 mm (0.63 inch) of bimetal armor at an angle of 60º. The sides and rear were 8.5 mm (0.33 inch) thick at varying angles, and the top and bottom hull were 6.5 mm (0.26 inch) thick. The front of the EE-9 was meant to protect from .50 machine gun fire at an unknown range, while the entire vehicle was protected from 7.62 mm AP rounds at 100 m (109 yards), and standard 7.62 mm rounds at 50 m (54 yards).
The average effectiveness of the bimetal plates was about 1.8 times the thickness of an equivalent homogeneous plate against 7.62 mm or 1.5 times the thickness against .50 machine gunfire. This meant that, against .50 machine gun fire, a 16 mm bimetal plate could be used instead of a 25 mm homogenous steel plate. These protection advantages over homogenous plates effectively meant that the Cascavel saved a lot of weight without compromising protection. The outer layer would shatter and blunt the incoming projectile, while the inner layer would relatively move with the bullet, slowing it down and stopping it without shattering.
The EE-9 M4 had two headlights and black-out lights integrated in both sides of the lower front plate. A rearview mirror could be mounted on both sides of the upper front plate. Below the driver’s vision block was a foldable windshield, which the driver could use when driving with an open hatch. The driver had access to 3 periscope sights mounted in a sort of vision block in front of him. The driver’s rotating sliding hatch was part of the top plate and was located behind the vision blocks. These periscopes and other periscopes or sights would not have been active or passive night vision equipment unless the Cascavel was ordered with these devices. The standard periscopes were manufactured by D.F. Vasconcellos.
A ventilation inlet was installed on both upper hull side plates. These ventilation inlets are recognizable by their frustum shape. A siren was installed behind the ventilation inlet on the right side of the vehicle. The fuel tank cap of the Cascavel was located on the left side, in the middle of the upper side hull plate, with the fuel tank installed on the hull floor. The EE-9 had a large ventilation grille on the rear of the vehicle, reminiscent of the M8, and had a rear light on both sides of the ventilation grill. The engine could be accessed through two large hatches on the hull top rear. The engine exhaust was located on the top right rear plate, as was unique to the EE-9 M4s.
The M4 used an adjustable ZF 8062 hydraulic powered steering wheel and had two pedals: the throttle on the right side of the steering wheel, and the brake to the right of the throttle. The gear selector was located to the right of the driver and the hand brake was located to the left. A control panel was located on the front left of the driver for, among other things, the headlights, siren, windshield, the various meters, and interior lighting. To the right was the pressure selector for the central tyre inflation system.
Mobility
The EE-9 M4 used the Detroit Diesel 6V53N V6 engine which produced 212 hp at 2,800 rpm and 598 Nm at 1,800 rpm. The engine had a total cylinder capacity of 5.212 liters, with a cylinder diameter of 98 mm and a stroke of 114 mm. The M4 Cascavel had a top speed of 95-100 km/h (59 mph) and an operational range of 750 km (466 miles).
It had a turning radius of 8.12 m (8.88 yards) and it could ford a depth of 1 m (3.3 feet). The Cascavel could climb a 65º slope, could climb a vertical obstacle of 0.60 m (2 feet), cross a 1.65 m (5.4 feet) trench, and had a ground clearance of about 0.5 m (1.6 feet). The front-wheel could travel for 0.2 m (0.66 feet), while the rear wheels could travel for 0.9 m (3 feet). It used 12 X 20 run-flat tires with a diameter of 0.5 m (1.6 feet). The EE-9 M2 had a distance between the front axle and rear axle of 3.05 m (10 feet), and a distance of 1.4 m (4.6 feet) between the two rear wheels.
The EE-9 M4 used an automatic Detroit Allison MT-643 transmission with four forward and one reverse gears. The transmission system could handle up to 250 hp and was the only transmission used in the EE-9s which could mount the Detroit 6V53 engine. The M7s would also use this transmission, but they were never paired with a Detroit when they were sold by Engesa.
In addition, the Cascavel used an Engesa 2 speed transfer case, which allowed the Cascavel to be used in reduced and high gear. By putting the Cascavel in reduced gear, horsepower was sacrificed for increased torque, making it more effective in climbing slopes. The vehicle was 6 x 6 driven, of which the rear 4 wheels were part of the Boomerang suspension. The Boomerang suspension, in combination with the Engesa 2 speed transfer case, enabled the Cascavel to cross challenging terrain and provide maximum traction in most situations.
The power of the engine was distributed to a differential on the front side of the vehicle, and a differential in the rear. The rear differential drove the Boomerang suspension with a single axle, which made the Boomerang suspension such an ingenious design.
In 1969, this suspension was invented by Engesa to enable trucks to transport oil to the refineries through rough terrain with bad infrastructure. With this suspension, the trucks could traverse otherwise untraversable hills for conventional suspension systems, as the wheels would always stay in contact with the ground to provide maximum traction.
The suspension system was a two wheeled-single axle driven suspension. The advantage of the Boomerang suspension was that it could be fitted on existing differentials with a single axle. Normally, this meant that the single axle, designed for the torsion forces of a single wheel, was subjected to the torsion forces of two wheels. Through excellent engineering, half of the torsion forces of the two wheels were mitigated by the suspension system built around the original axle. This design not only enabled the drive of two wheels by a single axle but, with clever usage of gears and bearings on both the axle and tube around the axle, the suspension system can rotate around its axle for 360º. This ability to rotate in extreme angles would enable the vehicles to traverse very difficult terrains and still provide maximum traction, as the suspension system curved with the terrain so that all the wheels were always in contact with the ground.
The Boomerang suspension used leaf springs for dampening. The two front wheels were used for steering. The wheels on the Boomerang suspension all rotated at the same speed. The front wheels were dampened by large coil springs. The vehicle used hydraulic disc brakes, and was steered with hydraulics as well.
A Central Tyre Inflation System (CTIS) came standard with the M4s. This system would help in obtaining the appropriate traction at various speeds by regulating the tyre pressure. This could help in crossing rough terrain but also save fuel. This was done by the driver through a switch. A Bendix Tu-flo 500 air compressor was used to provide the air flow and pressure for the CTIS.
Turret
The EE-9 ET-25 used an all-welded bi-metal steel construction to protect against small arms fire. The armor layout of the ET-25 is unknown, but considering the weight of the turret, it would quite likely be similar to that of the ET-90 II turret. This would mean that the ET-25 would have had 16 mm of bimetal armor at the front and 8 mm at the side, rear and top. This would make sense since the hull had a similar armor layout.
The turret front had a wedge shape with the 25 mm KBA autocannon in the gun mount being located in the middle. A coaxial 7.62 mm machine gun was located to the left of the turret in a separate mounting system which seemed to be slaved to the elevation of the main armament. Two lifting hooks were attached to the front side plates, one on each side of the turret. A main armament slaved search light was mounted on the left front side of the turret and a spent shell case ejection system was located in a depression on the right front side of the turret. The shell election system was further protected by two steel covers. The turret had three electrically operated 81 mm smoke dischargers on each side of the rear side plates.
The commander was located on the left side of the turret and had access to a raised cupola. The cupola was able to receive the ET-50 .50 machine gun mount as well for the commander and had a rear-opening hinge hatch. The commander had access to an unknown 3x day periscope which could be replaced by a 2.7x magnification night periscope. In addition, the commander had access to four 1x magnification periscopes located circularly around the hatch.
The gunner was located on the right and had access to a day/night sight as the main gun sight. The sight type is unspecified, but considering Engesa and Iraq widely used the SS-122 sight on the Cascavels and considering the magnification levels listed, it is quite likely the ET-25 uses an SS-122 sight. The SS-122 sight was an image intensifier sight which provided 10x magnification for the day sight and 9x for the passive night vision channel. The sight mirrors were coupled to the main armament to allow for automatic elevation of the sight mirrors in accordance with the gun elevation.
On the ET-25, the sight used an integrated laser rangefinder and offered graticules for air engagements. The turret did not seem to have utilized the SS-123FC fire-control system however, as the turret description does not mention the turret having access to a system providing a moving aiming mark for the sights. As such, target engagement would have had to be done through manual operation of the turret drives and the necessary lead caused by moving helicopters would have had to be estimated by the gunner. This effectively meant that, while the EE-9 ET-25 was to serve as practically the last line of defense of a convoy, it did not have all the potential tools at its disposal to somewhat reliably engage fast moving helicopters.
The turret used an electrically powered traverse and elevation system which was powered by the gunner’s controls. This enabled the ET-25 turret to have a turret traverse speed of 36°/s and an elevation speed of 21°/s. The turret offered a gun depression of -10° and an elevation of +55°. It had a 1.6 m turret diameter, which was the same as the other EE-9 turrets, and had a 0.63 m penetration depth within the hull.
Armament
The EE-9 with ET-25 was armed with an Oerlikon 25 mm KBA autocannon. The 25 mm KBA had a total length of 2,888 mm and a barrel length including muzzle brake of 2,173 mm. It had a recoil stroke of 25 to 34 mm and weighed 112 kg in total. The KBA used a double belt feed, allowing for two types of ammunition to be fired and offered multiple firing modes. It could fire in single shot, programmable rapid single shot with a rate of fire of up to 200 rounds per minute and fully automatic with a rate of fire of 600 rounds per minute. The gun was described by an ex-Engesa employee as a work of engineering art.
The 25 mm KBA has seen service on a wide array of vehicles including infantry fighting vehicles, reconnaissance vehicles, armored personnel carriers, and anti-aircraft vehicles. Most autocannon based anti-aircraft vehicles used at least multiple cannons and had some form of fire-control system to help track air targets, two things which the ET-25 did not have. In addition, practically all other uses with a single autocannon were on reconnaissance vehicles or infantry fighting vehicles where engaging air targets was a secondary mission, not the main objective, as with the EE-9 ET-25.
The ET-25 had 325 ready-use rounds for the 25 mm autocannon, of which 190 would have been High-Explosive Incendiary rounds and 135 would have been Armor-Piercing Discarding-Sabot ammunition. The latter could penetrate up to 25 mm of steel at 2,000 m at an inclination of 30°. It had an effective firing range of 3,020 m and a maximum firing range of 5,850 m. The APDS ammunition would reach a target at 2,000 m in 1.7 s and the HEI in 3.3 s.
In addition, the ET-25 had 200 ready use rounds for the coaxial 7.62 model F-1 machine gun. It supposedly also had 200 rounds in reserve, which would be somewhat strange, as the standard ET-90 turrets had 2,000 rounds in reserve for the coaxial machine gun, which seems a more likely value. In addition, a .50 machine gun could be mounted, which would likely entail that some 7.62 ammunition boxes would have had to be swapped out for .50 boxes instead. The amount of reserve 25 mm ammunition the EE-9 ET-25 carried is unknown.
Fate
In the end, the EE-9 with ET-25 turret failed to get any sales. After testing, Iraq returned the turret to Engesa, where it was supposedly scrapped. The EE-9 ET-25 concept seemed to have mainly suffered from the flaw of being everything and nothing. While the 25 mm KBA was used for anti-aircraft purposes on vehicles, autocannon armed anti-aircraft vehicles usually had multiple autocannons and a fire-control system to help engage the air targets. The ET-25 had neither of these and was already lacking in acting as an anti-aircraft vehicle, especially as a last line of defense. In addition, an ex-Engesa employee recalled the tendency of the Iraqis to make widespread use of heavy machine guns to achieve somewhat similar results.
In addition, vehicles that did use a single 25 mm autocannon were usually either reconnaissance vehicles or infantry fighting vehicles. This issue with using the EE-9 ET-25 as a reconnaissance vehicle was that it was a more expensive 90 mm armed EE-9 which also served as a reconnaissance vehicle.
The autocannon alone was already about US$100,000 in 1988 compared to the US$60,000 for the 90 mm gun. In addition, the turret structure itself was also US$5,000 more expensive than a standard ET-90 turret (US$45,000 compared to US$40,000). Had the buyer requested the turret drives to be installed as well, the turret price would have increased with an additional US$58,000. This would have made a fully outfitted EE-9 ET-25, which would have been somewhat capable of fighting off helicopters, cost about US$361,000 compared to the standard Cascavel at US$258,000 without turret drives.
With regards to serving as an infantry fighting vehicle, the Brazilian Army had already identified in the mid-1970s that the EE-9 Cascavel would be unfit for such use due to its lack of armor. Additionally, it could not transport troops either, turning it into either a fire support vehicle or reconnaissance vehicle. The EE-9 ET-25 would have been outclassed by the more cost-effective 90 mm armed EE-9 in both roles.
Additionally, from 1987 onwards and even before, financial war fatigue had reached the Iraqi government. After 7 years of fighting, stalemate, and being the largest arms importer throughout this period, the Iraqi coffers had started to run dry. In its quest to find new and more arms to tip the scales in its favor, the Iraqi government proceeded spending itself into potential bankruptcy. Among the arms to be bought by the Iraqis were for example Astros 2 rocket ammunition, which ended up being stockpiled by Avibras to then be sold to Saudi Arabia in 1991 and used against Iraq in the Gulf War. It is quite likely that Iraq simply could not afford such a specialized and seemingly not very effective vehicle like the EE-9 ET-25.
Conclusion
The EE-9 ET-25 turned out to be the only EE-9 to receive a different main gun than the original 90 mm gun by Engesa or the initial 37 mm. But for all the goals, it seemed to have failed in actually delivering on those promises. It was a jack-of-all trades vehicle with all the shortcomings a jack-of-all trades tends entail. It lacked the ammunition volume and fire control system to serve as an effective anti-aircraft vehicle, the cost-effectiveness to serve as a reconnaissance vehicle, and the armor and infantry carrying capability to serve as an infantry fighting vehicle.
Why exactly the Iraqis did not decide to buy the vehicle is unknown, but it is a possibility that the Iraqi staff had also recognized these flaws. In addition, Iraq simply could not afford the armament which it once could anymore. In short, the EE-9 ET-25 was, for all intents and purposes, a failure in both concept and sales.
Specifications (EE-9 M4 ET-25)
Dimensions (L-W-H)
5.3 (with gun) x 2.59 x 2.57 m (17.4 feet x 8.5 feet x 8.4 feet)
Total weight
12.5 tonnes (13.8 US tons)
Crew
3 (Driver, commander, gunner)
Propulsion
Detroit Diesel 6V53 212 hp engine (or OM352A 172 hp engine)
Speed (road)
95-100 km/h (59 mph)
Operational range
750 km (466 miles)
Armament
25 mm KBA autocannon
7.62 mm N model F-1 (coaxial)
Optional .50 machine gun (turret top)
Armor
Hull Bimetal
Front 16 mm (0.63 inch)
Side 8 mm (0.32 inch)
Rear 8 mm (0.32 inch)
Top 6.5 mm (0.26 inch)
Floor 6.5 mm (0.26 inch)
ET-25 turret (Estimated)
Front 16 mm (0.63 inch)
Side 8 mm (0.32 inch)
Rear 8 mm (0.32 inch)
Top 8 mm (0.32 inch)
Produced
1
Special thanks to Expedito Carlos Stephani Bastos, the leading expert of Brazilian armored vehicles https://ecsbdefesa.com.br/, Jose Antonio Valls, an Ex-Engesa employee and expert in Engesa vehicles, Paulo Bastos, another leading expert of Brazilian Armored vehicles and the author of the book on Brazilian Stuarts and the website https://tecnodefesa.com.br, Adriano Santiago Garcia, a Captain in the Brazilian Army and ex-company commander on the Leopard 1 and ex-lecturer on the Brazilian Armored School, and Guilherme Travassus Silva, a Brazilian with whom I was able to endlessly discuss Brazilian Vehicles and who was always willing to listen to my near endless ability to talk about them.
Sources
Engesa EE-9 Cascavel 40 anos de combates 1977-2017 – Expedito Carlos Stephani Bastos
Brazilian Engesa EE-9 Cascavel 6×6 at war 1977-2020 – Expedito Carlos Stephani Bastos
Blindados no Brasil – Expedito Carlos Stephani Bastos
Engesa manuals
Engesa brochures
Dual Harness skin stops armor-piercing projectiles Article of Richard M. Ogórkiewicz
Personal correspondence with Ex-Engesa Employees
Personal correspondence with Expedito Carlos Stephani Bastos
Personal correspondence with Paulo Roberto Bastos Jr.
Personal correspondence with Adriano Santiago Garcia
United States of America (1942-1944)
Medium Armored Car – 218 Built
With the successful employment of wheeled reconnaissance vehicles by Nazi Germany during the Fall of France, demand for such vehicles rose in the United States as well. Multiple branches within the United States military would set out requirements for a reconnaissance vehicle, but it would take up to late 1942 for these requirements to actually give an idea of what the US Army wanted. As a result, the Army was willing to fund any armored car project as a way of seeing what would stick when detailed requirements were made.
One of the resulting vehicles to fill the potential reconnaissance requirements was the 6×6 T17 Deerhound from Ford, not to be confused with the 4×4 T17E1 Staghound from Chrysler. The first prototype was delivered in March 1942, and, soon after, a second prototype with a 3-man turret would be delivered. Initially, the T17 Deerhound seemed promising, but the United States would lose interest when they had finally released their detailed requirements, which called for the M8 Greyhound instead.
The British were the next in line and requested the US Army to carry out desert trials. The vehicles performed so badly during these trials that the British gave up on fixing the vehicle too. The T17s were then transferred to the Military Police with their guns removed, and surprisingly, 54 of them would end up in Brazil. This made Brazil the sole operator of the T17 in combat units and, as a result, all four surviving T17s are in Brazil.
T17 and T17E1?
The T17 Deerhound is frequently confused with its much more successful ‘brother’, known as the T17E1 Staghound. It does not help that the designations of both vehicles are, for all intents and purposes, the same, and that T17E1 is frequently shortened to T17, as the Staghound was the only vehicle of the two to see successful large-scale service. The T17 Deerhound and T17E1 Staghound were very different however.
The program of these so-called medium armored cars started off with the T17 and T17E1 being competitors of each other. The T17 was designed and built by Ford, while the T17E1 came from Chevrolet. In addition, the T17 was a 6×6 vehicle, the T17E1 was a 4×4. Interestingly, however, the weight of both vehicles was almost the same, 13 tonnes (28.600 lbs) empty for the T17 and 12.3 tonnes (27.200 lbs) empty for the T17E1. Because of this, the T17 was seen more favorably due to its weight distribution, but its issues would end up much more difficult to fix compared to the T17E1’s issues. This eventually resulted in the cancellation of the T17 and the success of the T17E1.
The Armored Car
The demand for a turreted wheeled reconnaissance armored car intensified with the Fall of France. The Wehrmacht had made excellent use of wheeled vehicles for reconnaissance missions, such as the Sd.Kfz.221 and Sd.Kfz.232, which inspired the newly created United States Armored Force (June 1940). Besides Armored Force, the Tank Destroyer Center and the Cavalry Forces also had requirements for a fast scout vehicle. The issue, however, which would last all the way up to December 1942, is that no real clarification or stance was yet made on what either of the three branches exactly wanted in their fast reconnaissance vehicles.
There was still an ongoing debate if a tracked vehicle was preferable to a wheeled vehicle. Tracked vehicles offered much better cross-country mobility due to the lower ground pressure, could be better armed and protected, but at the same time were more noisy, needed more fuel, and required more maintenance. Wheeled vehicles were much quicker over roads and were overall more quiet compared to their tracked counterparts. Because of this, the tracked or wheeled debate depended on doctrine. If Armored Force expected to have to fight over reconnaissance, a tracked platform would be more suitable than a more stealthy wheeled platform. No formal stance was yet declared on what the Armored Force exactly envisioned in their reconnaissance doctrine all the way up to 1941.
As such, the Ordnance Department and the US Army were willing to fund both the development of armored cars and light tanks simultaneously. Due to the lack of clarity in what kind of armored car was requested, the type was further divided into light, medium, and heavy armored cars. It is important to note that this classification mainly referred to the armor protection level of the vehicles and not its armament. All of the earlier prototypes were to be armed with 37 mm cannons regardless of their classification. By Spring 1941, the British would also put forward their requirements for armored cars to be developed and built in the United States.
In summary, the lack of clear vision, the need to rapidly design and develop armored vehicles for the Second World War, and the large range of requirements would cause the US Army to fund too many projects. Each of these would may or may not fit within the yet to be determined doctrine. Arguments could be made for and against such a way of rapid design and development. On the one hand, a lack of consolidated effort caused delays in getting a new vehicle in the field. On the other hand, due to the wide range of vehicles developed, the Armored Force was able to pick the exact vehicle they wanted. Early war armored car development of the United States could be seen as throwing designs at the wall and seeing what stuck.
The Medium Armored Car
Since the United States Army did not have clear requirements on what kind of armored car it wanted, it would not have been a surprise that it was the industry to come forward with a medium armored car design proposal in the shape of the T13. The rather fittingly named Trackless Tank Corporation came forward with an 8-wheeled medium armored car. While the Trackless Tank Corporation initially proposed it as a replacement for a light tank (hence the name of the Corporation), the Army seemed to have been less enthused with the notion or with the inexperience of the company, as this was their first actual design.
A demonstration model, without a turret or armored plates, was tested by Armored Force in March 1941. The results of the trials were promising, as the suspension and mobility of the vehicle proved to be excellent. In the end, the inexperience of the Trackless Tank Corporation caused the T13 to have too many structural design flaws that even the more experienced Reo Motor Company could not solve. After multiple failed trials and reworks, further development of the T13 was suspended on July 23rd 1942 with full cancellation by December to January.
By spring 1941, the British Army and Armored Force, which had started to compile a list of specifications based on British experiences in Africa, put forward their requirements. These seem to have subsequently been more or less merged together to provide a single list to work with for new armored cars to be developed alongside the T13. These projects were known as the T17 and the T18 and procurement for one prototype of each was authorized. Ordnance put forward its requirements to the industry in July 1941.
The T17 Program
With the requirements published, both Ford Motor Company and the Chevrolet Division of General Motors put forward promising designs. Both designs were promising enough that funding for two prototypes each was arranged and Ford was allowed to develop the 6-wheeled T17 and Chevrolet the 4-wheeled T17E1.
Development and construction of the first T17 prototype was done quite rapidly due to the use of off the shelf components. A few changes were made from the initial proposal however. Ford had proposed to power the vehicle with two 90 hp engines, but in the interest of standardization, these were altered to two 110 hp Hercules JXD engines instead. The Hercules JXD was, for example, already in use with the M3A1 Scout Car and 2.5 ton (2.3 tonnes) trucks. In addition, Ford had proposed the use of rolled face-hardened steel plates, but this was changed to homogeneous steel armor plates instead to permit weldability. The latter decision compromised between armor effectiveness and buildability of the T17.
The T17 and T17E1 would use the same turret. The turret was developed by Rock Island Arsenal and was a redesign of the M3 Lee medium tank 37 mm armed turret concept. The turret was redesigned to match British and altered American requirements. It was to be manned by at least 2 crew members side by side with the gun in the middle and a bustle added to accommodate a radio set in the turret for the commander according to British practice.
As a result, the T17 was to be manned by 4 crew members, have a frontal armor of 2 inch (50 mm) and 1.25 inch (32 mm), side armor of 0.75 and 0.875 inch (19 and 22 mm respectively), rear armor of 0.75 inch (19 mm), and turret armor ranging from 2 inch (50 mm) frontally to 0.5 inch (13 mm) on the top. It would carry a 37 mm gun and a .30 coaxial machine gun in the M24 combination mount. The turret was to have a hydraulic turret traverse and a gyrostabilizer. A top speed of 55 mph (88 kph) was expected.
In reality, very little of these requirements were actually used in the production models. Armor was decreased to 0.75 inch (19 mm) frontally, the side was decreased to 0.75 inch (19 mm), and the rear to 0.5 inch (13 mm). The turret armor was decreased to 1.25 inch (32 mm) with a turret top armor of 0.75 inch (19 mm). The crew would be increased to 5 with the usage of a 3-man turret, and the gyrostabilizer was not implemented.
Specification
Initial requirements
Production model specifications
Crew
4
5
Frontal armor
1.25 to 2 inch (32 to 50 mm)
0.75 inch (19 mm)
Side armor
0.75 to 0.875 inch (19 to 22 mm)
0.75 inch (19 mm)
Turret armor
2 inch (50 mm)
1.25 inch (32 mm)
Stabilisation
Yes
No
The first prototype was delivered to Aberdeen Proving Ground about 6 months after authorization was given and development started on March 1942. But even before the first prototype was built, the US Army authorized Ford to manufacture 2,260 T17 armored cars in January 1942. This early production order was not surprising, as the Japanese had launched the attack on Pearl Harbor, which would lead to United States’ participation as a combatant in World War 2. The United States needed vehicles and it needed them now. Simultaneously, 2,000 T17E1s were ordered by the United States as well. A month after the first T17 prototype was delivered, the order was increased to 3,760 vehicles.
At some point, a second prototype was delivered to the Armored Force Board at Fort Knox for testing. This prototype utilized a 3-man turret rather than the 2-man turret of the first pilot vehicle. The turrets were also supposed to have stabilizers, but this was apparently requested too late to be incorporated in the production design. The engine intake and engine deck were also redesigned. When and why this redesign was carried out is unclear, although it would have increased the overall combat efficiency of the vehicle. This alteration increased the total crew to 5. Almost nothing is known of the testing phase of both the initial pilot vehicles, except for the fuel economy of the second pilot model.
Gear
MPH
MPG
1st
1.5 (2.4 km/h)
0.56 (0.24 km/l)
1st
2.9 (4.7 km/h)
0.50 (0.21 km/l)
1st
5.0 (8 km/h)
0.43 (0.18 km/l)
2nd
3.4 (5.5 km/h)
0.94 (0.4 km/l)
2nd
6.6 (10.6 km/h)
0.87 (0.37 km/l)
2nd
9.5 (15 km/h)
0.71 (0.3 km/l)
3rd
5.5 (8.9 km/h)
1.99 (0.85 km/l)
3rd
10.1 (16.2 km/h)
1.78 (0.76 km/l)
3rd
15.4 (24.8 km/h)
1.85 (0.79 km/l)
3rd
30.3 (48.8 km/h)
1.63 (0.69 km/l)
The British noted in July 1942 that the United States was reserving the T17 for themselves and also noted that, at that point, the T17 seemed the superior vehicle over the T17E1. As such, considering the British correspondence and the order increase, the pilots seem to have performed at least acceptable at that point in time.
The development of winterization equipment for the T17 started on July 5th 1942. This equipment would have included heaters for the engine, battery, and crew compartment, an engine primer, special windshield, and engine inlet and outlet shutters.
From the Americans to the British
During 1942, all seemed to have gone well for the T17 Deerhound. The Americans had put forward their intention to build the vehicle just for themselves and, as a result, the request for additional stowage according to the British requirements was not to be carried out. Provisional reports in September 1942 estimated that 250 T17 Deerhounds would be manufactured by the end of the year.
However, the Armored Force Board realized it had too many projects going on simultaneously as a result of not having set clear requirements of what they wanted. In an effort to start standardizing production and to make sense of the mess they had created together with the British, the Special Armored Force Board under Brigadier General W. B. Palmer was created in Autumn 1942. They first met in October of that year to examine the numerous projects going on.
The so-called Palmer Board was quite relentless and strongly favored light armored cars. Armored Force Doctrine now finally decided that reconnaissance was to be done by small, cheap, and ‘sneaky’ vehicles, as opposed to vehicles capable of fighting in close combat. In essence, a reconnaissance vehicle was supposed to do reconnaissance and was not supposed to participate in combat unless forced to. Any armored car development heavier than 20,000 lb (9.1 tonnes) was to be canceled immediately. The Armored Force did attempt to keep the T19 medium armored car in development, but it eventually was not able to sufficiently defend the development of the vehicle. As a result, the Gun Motor Carriage T22 was to be standardized and became the M8 Greyhound.
The T17 Deerhound contract was reduced to 250 vehicles, which was the expected production of 1942. While development was essentially canceled for both the T17 and the T17E1 from the US’ point of view, the production had already begun and it was perhaps unnecessary to immediately cancel production. In addition, the 250 vehicle production contract was also allowed to be carried out until Ford could transition to manufacture M8 Greyhounds instead and to compensate for the losses of production tooling. The British were still in the position to formally request the production of an armored car anyway, even if it was solely to fill their requirements. As a result, further testing of the T17 and T17E1 for desert warfare was formally requested by the British Army at some point in January 1943.
It is likely that, at this point, the T17 also received its nickname from the British as M5 Deerhound. The exact date of when the T17 received its name is unknown. Since the T17 was never formally accepted into service by the Americans, it would have remained T17 for them. Interestingly, in all British Army Staff correspondence files, the Deerhound is referred to as simply T17 throughout its development.
By January 1943, 125 T17s were manufactured, of which 70 were in depots and it was hoped that 50 could be shipped out in the same month already. Each vehicle was to be shipped with 3 spare tyres and 1 extra wheel. The availability of spares was deemed enough for the following 2 years, as the production was initially set to close when the 250th vehicle was finished. The first 100 vehicles would use some different equipment, as upgrading the backlog was not advised at the time.
Modification Challenges
From February 1943 onwards, a significant British effort can be seen to get the T17 tested and eventually in service with as many modifications to British requirements as possible. The modification program would be faced with increasing challenges, as testing and production went on. The British requirements included the addition of a sight vane, sun compass, brackets for equipment such as a signal pistol, anti-aircraft machine gun mount, and a smoke mortar. The switch to British ownership also meant that the initially planned American SCR 508 radio was to be replaced with a British No. 19 R/T radio instead.
The first problem was that the 100 T17s which were already built had been spread out to various ports in the United States. This made a consolidated effort for the implementation of the planned modifications increasingly difficult. It did not help either that, as trials went on, more significant issues came to light which would require significant modification on components, such as the drive shafts. The second was that, of the 150 newly produced T17s which were to be built according to British standards, only 25 ended up actually being manufactured to fit those requirements in April 1943. Efforts were made later on to still get the modifications implemented on the remaining 125 vehicles, but since the T17 project was canceled by June-July, only 75 vehicles seem to have been rebuilt to British standards. After the cancellation, the British attempted to get the 75 No.19 radios back, but it is unknown if they were successful in this endeavor.
Desert Trials
Desert testing began on February 15th 1943 with the arrival of 6 T17s at the Desert Warfare Board Headquarters at Camp Young, Indio California. The armored cars were to undertake a 5,000 mile (8,047 km) long endurance test, of which 50% was on-road and 50% off-road. Afterwards, two vehicles were to be driven until they broke down enough that a major overhaul was needed.
Already after a month of testing, by March 18th, advice was given to only field the T17s at locations with proper maintenance facilities, as they were said to be far from being sound mechanically. After having run all 6 vehicles for about 400 miles (644 km) each, all vehicles presented issues with the intermediate axle due to torsion and the joints of the front axle were faulty as well and replaced. As a result, the initial plan to field the 100 already built T17s in Iraq was canceled and T17E1s were fielded there instead.
In the following month, by April 2nd, it was noted that the armored car was ‘’far from robust’’. All 6 vehicles received special heat treated axle housings, strengthened intermediate axles, reinforced hydraulic steering booster brackets,strengthened pillow block bearings at the intermediate shaft for rear axle drive, new front axle shock absorbers, and the installation of solid drive shafts opposed to tubular drive shafts. All the previously mentioned changes were to be applied to all planned 250 vehicles.
T17 serial number
Total Mileage
Performance
2062
1,030 miles (1,658 km)
The steering booster bracket and pillow block bearing were reinforced after 376 miles (605 km). At 550 miles (885 km), the intermediate drive axle was damaged as well. At 623 miles (1,002 km), the rear axle of the drive gear stripped its teeth. New axle gears, drive shafts, and axle shock absorbers. Metal to metal hitting was noted during tests, but no axles were bent.
2052
803 miles (1,292 km)
A new rear axle was installed and the front axle was straightened. New drive shafts were fitted between the intermediate and rear axles and the steering booster bracket and pillow block bearing were reinforced.
2083
996 miles (1,603 km)
Intermediate and rear axle drive shafts replaced and steering booster bracket reinforced.
2110
556 miles (895 km)
New front axle installed and steering booster brackets and pillow block bearing reinforced.
2092
929 miles (1,495 km)
Steering booster bracket and pillow block bearing reinforced.
2041
402 miles (647 km)
This T17 was essentially cannibalized to keep the other 5 T17s running. The front wheel propellor shaft grease seal, pillow block bracket, intermediate axle drive shaft were all broken. Front and rear axles bent.
The vehicles were further tested in the following 15 days until April 15th. While less failures were reported, the adaptation of solid drive shafts and installation of new bumper brackets was not yet carried out due to the shafts not being available yet. It was estimated that the solid drive shafts would arrive by May 8th. If full scale adoption of the new drive shafts on the planned 250 vehicles should have been carried out would depend on further testing. It is possible that not much was reported simply because the issues were already known and they could not be fixed yet.
T17 serial number
Total Mileage
Performance
2062
1,313 miles (2,113 km)
The right front spring was replaced and the steering booster bracket broke twice at the seal.
2052
1,083 miles (1,743 km)
No events were noted.
2083
1,273 miles (2,049 km)
Drive shaft bearing broke at both engines.
2110
926 miles (1,490 km)
Left engine drive shaft broke.
2092
1,001 miles (1,611 km)
Bent rear axle.
2041
402 miles (647 km)
Transfer case had failed and was repaired, but due to the lack of components was still unusable for further testing at this time.
By June 5th, the trials were effectively finalized. Five T17s were fitted with new solid steel drive shafts instead of hollow shafts. In addition, new bumper brackets were installed on all three axles. The vehicles were tested over moderate sand surfaces and not taken into excessively difficult terrain or conditions which would not be encountered in theaters of operation. The new drive shafts jammed in their housings, which was likely caused due to the joints not being hardened. As a consequence, three universal joint bolts snapped off, in two cases the pillow block bracket broke off and in two cases the front axle differential casing sailed. The adoption of bumper brackets was successful in completely removing the issue of any bent axles since installation.
T17 serial number
Total Mileage
Performance
2062
1,714 miles (2,758 km)
Unit did not take part in tests due to lacking a fan assembly and a spider connector for the drive shaft.
2052
1,863 miles (2,998 km)
At 1,164 miles (1873 km), a bent front axle was replaced. At 1,347 miles (2,168 km), the universal joint bolt was broken. At 1,738 miles (2,797 km), the front end failed. The carriage was faulty and the ring gear and pinion were in bad order. Three teeth of the ring gear were broken and there was a slight oil leak in the intermediate axle.
2083
1,353 miles (2,177 km)
Pillow block bolts broke off due to problematic drive shafts. In an attempt to continue with just the front and intermediate axles, the universal joint bolt snapped.
2110
1,144 miles (1,841 km)
At 1,097 miles (1,765 km), front end failed due to a ‘’complete disintegration of carriage front axle assembly.’’
2092
1,325 miles (2,132 km)
At 1,279 miles (2,058 km), differential bolts loose and drive shafts overheating due to sticking in the joints.
2041
604 miles (972 km)
Repaired to running condition after suffering a breakdown and cannibalization. At 552 miles (888 km), the steering bracket broke off. At 592 miles (953 km), new drive shafts jammed, causing a universal joint bolt to snap and the pillow block bracket broke off. The shafts jammed due to the joints not being case hardened, which resulted in all the previously mentioned damage.
The results of the trials were discussed with Ford Motor Company, which claimed that the trials were unnecessarily severe. The Company also noted that the original hollow drive shafts should be implemented with the strengthened pillow block brackets and the bumper brackets, as that would eliminate the shaft bending without the need to implement solid shafts. Ford proposed a comparative trial between hollow and solid drive shafts on the six T17s in testing to determine if hollow drive shafts were still feasible.
The British received a report from the Desert Warfare Board on the T17 which was so damning that the British requested the United States to cancel the assignment of all 218 T17s,
as they were not worth shipping. In July 1943, the T17 was officially canceled by the British due to the extreme mechanical breakdowns the T17s had suffered, the necessary extensive redesign of components, and the difficulty of implementing all the needed changes on the spread out fleet of T17s. On top of the terrible performance of the T17, it turned out that, by the time the T17 was canceled, just 218 T17s had been built instead of the contracted 250.
Considering full-scale adoption of, for example, new drive shafts depended on how they performed in testing, it is very unlikely that any of the manufactured T17s would have received these, apart from the ones undergoing testing. It is quite likely that none of the design errors which came to light during the Desert Trials would have been fixed in the production vehicles, as testing was not yet finalized. Considering the issues with the drive shafts, it almost seems that Ford underdefined the needed strength of the components, with catastrophic failure at short operational distances as a result.
On top of that, it seems strange that these issues only really came to light during the Desert Trials. There is practically no negative mention on the T17 before the desert trials. This seems odd, as the Americans did test the vehicles at Aberdeen Proving Ground. Why it took over a year to discover that the T17 was extremely mechanically unreliable after the first vehicle entered tests is a mystery.
The 37 mm guns were to be removed from the T17s and they were put to use with the Military Police in the United States. The T17 project was fully terminated by February 1944, likely with the removal of the 37 mm guns and the vehicles entering service with the Military Police. Surprisingly, 54 T17 Deerhounds with their 37 mm guns would end up making their way to Brazil, where they would serve until the 1970s.
Trials on the Side
In addition, four other trials in Utica (New York), Phoenix (Arizona), Milford (Connecticut), and Manitoba (Canada) were carried out. In February, the T17 at Utica drove 136 miles (219 km) and had a malfunctioning accelerator pedal and the siren was inoperative. The Milford T17 needed a front axle replacement after 291 miles (468 km). The Phoenix T17 was not tested during this month.
In March, the Utica T17 had a broken steering knuckle and the front axle casing was bent after 357 miles (575 km) in total (including the initial 136 miles (219 km)). The Milford T17 had received a new front axle casing, but the propellor shaft vibrated heavily due to it being bent for unknown reasons after 873 miles (1,405 km). The Phoenix T17 had a failure in the accelerator control due to air entering the hydraulics after 4,388 miles (7,062 km).
In April, the Utica T17 broke its left front spring, had a failure in the intermediate axle house, severed two hull bumpers for the axles, and was plagued with oil leakages and faulty grease seals after 666 miles (1,072 km) in total . The Milford T17 had a driveshaft failure after 1,141 miles (1,836 km), while the Phoenix T17 did not seem to have been tested that month.
The Phoenix T17 seems to have performed remarkably during these trials, beating out all the other T17s by far and in just a month. It also does not seem to have had any of the extreme drive shaft issues the other T17s had. Due to the extreme distance driven and the significant lack of breakdowns reported within a month of testing, it could be that the range was simply mistyped in the report.
The T17 was also tested at Camp Shilo in Manitoba, Canada, during the winter of 1942-43 by the Winter Test Detachment. By December 1942, the further development of winterization equipment was dropped for the T17 due to the small production numbers.
The T17 Deerhound in Detail
The T17 Deerhound weighed 14.3 US tons (13 tonnes) empty and 16 US tons (14.5 tonnes) combat loaded. It was 18.2 feet (5.5 m) long, 8.5 feet (2.6 m) wide, and 7.6 feet (2.4 m) tall. The armored car had a crew of five, with the driver in the front left, the co-driver in the front right. The gunner sat in the front left side of the turret, with the commander positioned behind him. The loader sat on the right side of the gun.
Hull
The T17 hull was armored with a combination of cast and plate homogenous steel. The frontal hull was 0.75 inch (19 mm) thick cast steel ranging from 47° to 57° to 42° from vertical for lower, middle and upper front plates, respectively. The sides were 0.75 inch (19 mm) thick steel plates, while the rear was 0.5 inch (13 mm) thick plate as well. The frontal hull top section was 0.625 inch thick cast steel, while the rear top was 0.375 inch (9.5 mm) thick steel plate. The floor was 0.25 inch (6.4 mm) thick die-formed steel plate.
The T17 had a headlight on each side of the middle front plate and a siren located to the right of the left headlight. The headlights could be switched out with blackout lights instead. A .30 M1919A4 ball mount hull machine gun was located on the right side of the middle hull plate. The driver and co-driver both have access to the vehicle through two hatches installed on the upper front plate. These hatches offer protected direct vision through steel shutters. The driver also had access to two 360º rotating M6 periscopes located on the top plate and the co-driver had access to one.
Three stowage boxes were placed on top of the fenders on each side. An additional larger stowage box could be installed on the left side under the fenders as well, in between the front and middle wheel. A hull door was located on the right lower side of the vehicle. A .45 Thompson submachine gun was located on the inside, above the hull door. The vehicle carried 450 or 320 .45 rounds for the Thompson in 30 or 20-round clips, respectively. In addition, 8 hand grenades would be available as well.
The exhaust was located at the rear, with a large rear fender. The rear lights and black out lights were attached on top of these exhaust fenders as well. Above the exhaust fenders was a plate which had hatches for lubricants but also for the fuel tank in the middle. It also offered mounting brackets for sapper tools. On the hull top were two large hatches in a raised position for the engine air intake. The lower rear plate featured two towing hooks.
The driver’s position was located on the front left of the vehicle. The driver used a hydraulically powered steering wheel and had the instrument panel in front of him. The gear shifting lever was located on the left and the transfer case control lever to the right. The clutch pedal was located on the left side of the steering wheel, while the throttle and brake were located to the right.
Mobility
The T17 Deerhound was powered by two Hercules JXD 6-cylinder in-line 110 hp at 3,200 rpm gasoline engines. The engines were placed in a parallel layout, making the total produced horsepower 220 at 3,200 rpm. The engines could generate 220 ft-lbs (298 Nm) of torque at 1,150 rpm each, for a total of 440 ft-lbs (597 Nm). The T17 used two transmissions, one for each engine, with 4 gears forward and 1 in reverse. In addition, it used a transfer case for high gear and low gear, effectively doubling the gears available for the vehicle to help in situations that required more torque control.
The vehicle could reach 50 mph (80 km/h) on road and had a maximum safe speed of 60 mph (96.5 km/h) down hill. As the engines were ungoverned, it was of paramount importance that the driver knew what speeds were allowed at each specific gear. The vehicle had a 75 gallon (284 l) fuel tank located in the engine bay, which meant that the vehicle could travel between 50 to 300 miles (80 to 483 km) cross-country and 300 to 400 miles (483 to 644 km) on paved roads. The Deerhound had a turning radius of 30 ft and a maximum fording depth at 4 mph of 32 inches (6.4 km/h of 0.81 m). The vehicle could climb a 60% slope and overcome an 18 inch tall vertical wall (0.46 m).
The vehicle had a ground clearance of 13.5 inches (0.34 m) and could cross a 1.5 feet (0.46 m) trench. The wheel base from front axle to middle axle was 96 inches and from middle to rear axle of 51 inches (1.3 m). The weight distribution was about 11,000 lb (5 tonnes) on the front axle and 10,000 lb (4.5 tonnes) on the middle and rear axle each. This gave the vehicle a ground pressure ranging from 70 lb/in2 (4.9 kg/cm2) on paved roads to 17.7 lb/in2 (1.2 kg/cm2) with 4 inch (0.1 m) of ground penetration in cross-country operation.
Running Gear
Each engine was coupled to its own Warner Gear Company synchromesh transmission with 4 gears forward and 1 in reverse. In addition, each engine had its own Long Manufacturing Company No. 12 CB-C clutch which was controlled by a single master clutch (the hydraulic clutch pedal) which engaged both at the same time, with both transmissions connected to the same shift mechanism. The gear shifting could be selected for each engine separately through a sliding button. When an engine was selected, the other engine would be declutched and run in neutral gear. The gear shift had to be in neutral to allow for safe switching of the engines. This system would theoretically allow the vehicle to be run on a single engine, but in practice, this was impossible due to the driveshafts not being able to handle the torque.
Transmission gear
Ratio
1st
6.499 to 1
2nd
3.543 to 1
3rd
1.752 to 1
4th
1 to 1
Reverse
6.987 to 1
The two drive shafts from the engines were brought together at the two-speed Warner transfer case. The transfer case then transmitted the power through 3 drive shafts, one going to the front, one going through the middle and one going to the rear axle. The transfer case offered two ratios, high gear (1.037 to 1) and low gear (1.941 to 1). Essentially, this meant that, theoretically, the vehicle had 8 gears instead of 4. This helped in running the vehicle more efficiently or to provide additional torque when needed. The transfer case could be selected for both or a specific engine as well. As the engines were not governed, it was up to the drivers skill and memory to not overspeed in the gears and damage the vehicle.
Gears
Gear ratio
Maximum allowable speed
Low ratio 1st gear
12.6 to 1
4 mph (6.4 km/h)
Low ratio 2nd gear
6.9 to 1
8 mph (12.9 km/h)
Low ratio 3rd gear
3.4 to 1
18 mph (29 km/h)
Low ratio 4th gear
1.9 to 1
32 mph (51.5 km/h)
Low ratio reverse
13.6 to 1
4 mph (6.4 km/h)
High ratio 1st gear
6.7 to 1
8 mph (12.9 km/h)
High ratio 1st gear
3.7 to 1
16 mph (25.7 km/h)
High ratio 2nd gear
1.8 to 1
32 mph (51.5 km/h)
High ratio 3rd gear
1.1 to 1
60 mph (96.6 km/h)
High ratio reverse
7.3 to 1
8 mph (12.9 km/h)
The vehicle had a total of 6 propeller or drive shafts. Two came from each of the transmission/engines and powered the transfer case. One went from the transfer case to the front differential and one went from the transfer case to the middle differential. Two drive shafts went to the rear differential. The first went from the transfer case to a pillow box attached to the intermediate differential axle (a connecting box between two shafts), from which the second drive shaft was powered and propelled to the rear differential.
These drive shafts were initially hollow, which helped save weight, decreased vibrations, and could transfer more torque. But when the shafts started to bend, it was decided to try and install solid shafts instead on the test vehicles. These could not be properly tested due to the shafts jamming at the improperly hardened joints, which caused them to fail due to torsion instead.
The drive shafts powered a total of three differentials with a gear ratio of 6.667 to 1, one for each pair of wheels. These differentials in turn powered hollow axles manufactured by Ford for the T17. The front axles were equipped with hydraulic shock absorbers and the front springs were leaf springs. The intermediate and rear axles used a special axle housing and also used hydraulic shock absorbers. The middle and rear differentials were connected to a bogey-style leaf spring suspension system. The Deerhound used hydraulic brakes and 12.00×20 tyres.
Turret
The turret was a one-piece cast steel piece with 1.25 inches (32 mm) of thickness all-round and 0.75 inches (19 mm) on the turret top and hatches. The small gun shield was 1 inch thick. The gun was placed off-center to the right, with the coaxial machine gun to the right of the 37 mm gun. To the left of the gun was a rotatable holder for the M4 periscope for the gunner. The M40 telescope, used by the gunner to aim, was integrated within the M4 periscope construction. The turret had two pistol ports on each side, which on the first prototype had vision slits, but these were removed in the production vehicle.
The loader had access to an M6 periscope in a 360º rotatable mount at the top front of the turret. The commander had access to two M6 periscopes, with one being integrated in the hatch and the other in a rotatable mount to the left of the loader’s periscope. Behind the periscopes were the hatch for the commander and gunner to the left and the hatch for the loader on the right. The radio antenna was located behind the commander’s hatch.
The T17 had manual and hydraulic traverse. The latter could traverse the turret at a speed of up to 3 revolutions per minute, or 1 full revolution per 20 seconds. The radio set was located behind the commander and loader in the turret bustle. On the right side of the radio, in the bustle, was space for 3 rounds of 37 mm ammunition and, on the other side, was space for another 8. The turret basket had room for 35 rounds of 37 mm ammunition spread around on the sides.
Armament
The T17 used a 37 mm M6 cannon as main armament in the M24 combination gun mount. The 37 mm M6 had a total length of 2.1 m (6.9 feet) and a bore length of 1.98 m (6.5 feet). It was able to fire the M51 APC round with 53 mm (2.1 inch) of penetration at 455 m (500 yards) at a 30º angle, and 46 mm (1.8 inch) of penetration at 915 m (1,000 yards) at a 30º angle. It could also fire the M74 AP, M63 HE, and M2 canister rounds. The 37 mm cannon had an elevation of +45° to -10° and had a potential fire rate of 30 rounds per minute.
In addition to the 37 mm cannon, the Deerhound mounted a coaxial .30 M1919A4 machine gun on the right side of the gun, and a .30 M1919A4 for the bow machine gun. The T17 had 5,500 rounds of .30 ammunition in total (of which 750 in the machine guns) and 110 rounds of 37 mm ammunition, of which 43 would have been in the turret and 68 stashed in the hull. Interestingly, British requirements also called for an anti-aircraft machine gun mount, but it is unclear to what point this mount was actually implemented.
Other Systems
The T17 Deerhound used a British No. 19 radio set, while initially it was planned with an SCR 508. The interphone had 5 stations and the vehicle also had an M238 flag set. The electrical system used 24 volts DC, powered by a 24 volts and 50 amperes main generator coupled to the engine. Two 12 volt batteries connected in series were used to start the engine and provide power to systems when the engine was off.
The T17 had two 10 lb (4.5 kg) CO2 fixed fire extinguishers for the engine bay and a single 4 lb (1.8 kg) hand fire extinguisher.
Service and the WACs
With rejection by both the US Army and the British Army, there were only a few places to go for the T17 Deerhounds. Surprisingly, 54 T17s would end up in Brazil, but the rest would have their guns removed and officially be used with the Military Police in the United States itself for patrol duties. Sadly, no pictures have been found of the T17 Deerhound in service with the Military Police. No T17 Deerhounds are known to remain in the United States. It is very likely that they were all either scrapped or used as range targets.
Interestingly, 2 T17 Deerhounds would appear in two pictures with the Women’s Army Corps (WAC) at the port of embarkation at Hampton Roads. Private Margaret Pochyla is seen directing the tanks, with Technician Fifth Grade Germaine La Voie and Private Geraldine Raymond riding in the first M3 Lee. The women were, according to the information on the pictures, part of the 1st WAC Company. While the picture was taken by the US Army Signal Corps, it is very likely that these women were part of the Transportation Corps which were stationed at the eight major ports of embarkation. About 13% of all WAC personnel (6% of the WAC forces, some 5,000 women) of Army Service Forces was allocated to the Transportation Corps during World War 2.
The WAC was created in 1942 as the Women’s Auxiliary Army Corps or WAAC, but was converted to active duty status in 1943. The WACs would be barred from active-combat roles, but this still left over 250 other jobs in which WACs could be employed to free up men for combat. Among these roles were the Transportation Corps at the ports of embarkation. The first WACs in Hampton Roads arrived on April 10th 1943 and would continue to serve up to the beginning of 1946, after which they were either discharged or transferred. Three WAC companies would serve at Hampton Roads by mid-1944 and still more women were requested to serve a variety of roles, from clerks to dispatchers of vehicles and ships.
The Transportation Corps WACs were employed for duties ranging from postal to pier work, helping in the embarking and disembarking of both men and materiel. Logically, the wide employment of WACs at the ports of embarkation meant that, while pier duty had priority, there were dozens of other jobs to be done. These jobs could include motor vehicle transportation but also performing mechanical maintenance and testing on vehicles to be shipped overseas.
Overall, WACs would be quite popular in and around signal and radio duties. Under Army Ground Forces, they would, for example, be employed in the repair of radios and the installation of radios in tanks and other vehicles. They would also be used to teach the servicemen in radio operations and would be employed widely as radio operators under the Signal Corps, as fewer men were available. While the women would find opposition in a large range of commands, the single biggest issue the WACs had to deal with in the Signal Corps and Transportation Corps was fatigue due to working long hours. Major General C. P. Gross, Chief of Transportation, would note on the WACs performance during World War 2:
“The WACs have demonstrated thoroughly their value to the Transportation Corps. They have become an integral part of our busy ports, not only because of the quality of their work, but also because of the enthusiasm they have displayed and their loyalty to the Transportation Corps and the entire Army. The demand for their services is growing daily…”
Brazilian Service
Perhaps the most surprising destination of the T17 Deerhounds was Brazil. Most sourcing on the T17 stated that they were rejected, had their guns removed, were given to the Military Police, and that none were shipped overseas. While it is technically correct that the T17s were not shipped overseas in regard to the United Kingdom or the Pacific theater, the rejected T17s were shipped overseas to Brazil. Which begs the question, why?
It turns out that Brazil receiving the T17 was likely nothing more than the United States equipment dumping the T17s instead of sending valuable M8 Greyhounds. Apparently, Brazil had ordered M8 Greyhounds under Lend-Lease and they received the 54 T17s instead with all the paperwork of the M8 Greyhounds. It is a bit unclear when the vehicles arrived in Brazil, as Brazilian sources mention both 1943 and 1944.
What is known for sure is that 18 T17s entered service with the Brazilian Army in September 1944 as reconnaissance and command vehicles. The T17s were delivered to two mechanized Army units and one military police battalion. This makes Brazil the only country to have operated the T17 in combat units, with one command T17 seeing service all the way to 1972.
The T17 Deerhound was not popular among Brazilian crews, as it retained the same problems that the T17s had during the Desert Trials. In addition, the Brazilians also noted synchronization issues in the dual-engine set up, causing even more issues with the vehicles. How the Brazilians managed to keep operating multiple T17s all the way up to the 1970s is perhaps nothing more than a miracle, or they simply did not use them a lot and their service was a paper reality instead.
Surviving Deerhounds
As far as it is known, only four T17 Deerhounds still exist in the world. All of these Deerhounds are in Brazil, being retired vehicles from the previous three regiments. The T17s are in mixed condition, with a single vehicle being the most complete, still having both engines, but missing a turret basket. One of the four vehicles is currently being restored by the Centro de Instrução de Blindados (CIBld) (English: Armored Personnel Training Centre).
The most complete T17 is located at the Museu Militar do Comando Militar Sul in Porto Alegre Rio Grande do Sul. This T17 has the registration EB10-170. Considering the 2º RRecMec was located in Porto Alegre, and the EB10-170 is not one of the 3º RRecMec designations, it is quite likely that this Deerhound came from the 2º RRecMec. What is interesting is that the EB10-170 registration is not on all pictures of this T17, suggesting that it might have been painted on at a later date and that the registration might not have been its original registration, or of any other T17 Deerhound at all.
Another T17 functioned as gate guardian at the 4º Batalahão de Logistica (English: 4th Logistics battalion) at Santa Maria, Rio Grande do Sul. This gate guardian has since been renovated by the CIBld, and is now presented at the Museu de Blindados do Centro de Instrução de Blindados in Santa Maria, Rio Grande do Sul. It has no registration. The hatches of this vehicle are supposedly welded shut, and as such, this vehicle has probably just received an exterior overhaul and is not in running condition.
The third T17 is located at the 1º Parque Regional Manutenção in Rio de Janeiro. Not much is known except that, between 2005 and present (2023), it seems that either the 37 mm gun has been removed or cut off. Considering that this Deerhound is located in Rio de Janeiro, it is quite likely that this vehicle originated from the BPE.
The fourth Deerhound is located at the Parque Histórico Marechal Manuel Luís Osório in Tramandaí, Rio Grande do Sul. This vehicle also does not have any registration, but considering it is located close to Porto Alegre, it is quite likely that this Deerhound came from the 2º RRecMec.
Conclusion
In the end, the T17 seems to have been realistically unfixable for it to have any use for the United States or the British. It performed abysmally during trials, and when the solid drive shafts meant to fix the problems failed as well due to improper hardening, it seems to have been the last drop for the British, who refused to put any more effort in the failed vehicle. The T17E1, while initially seeming less promising, simply had issues which were much easier to fix.
It almost seems that Ford had under defined their design, which would lead to all the drive shafts and axles failing. As a result, the T17 was put to further use with the Military Police for patrol duties and as M8 Greyhounds in disguise for the Brazilians. Brazil became the end of the line for the T17, where it would continue to serve all the way up to the 1970s, albeit with the same issues which arose during tests. As such, like the T13 Medium Armored Car before it, the T17 ended up as a failed and fairly forgotten project, being overshadowed by the T17E1 Staghound and the M8 Greyhound.
Specifications (T17 Deerhound)
Dimensions (L-W-H)
5.5 m x 2.6 m x 2.3 m (16.4 feet x 7.5 feet x 7.5 feet)
Total weight, combat loaded
14.5 tonnes (16 US tons)
Crew
5 (driver, co-driver, commander, gunner, loader)
Propulsion
Two Hercules JXD 6-cylinder in-line 110 hp gasoline engine
Hull
Front upper 19 mm (0.75 inch)
Front middle 19 mm (0.75 inch)
Front lower 19 mm (0.75 inch)
Side 19 mm (0.75 inch)
Rear 12.7 mm (0.5 inch)
Top 16 to 9.5 mm (0.625-0.375 inch)
Floor 6.5 mm (0.25 inch)
Turret
Front 32 mm (1.25 inch)
Gun mantlet 25 mm (1 inch)
Sides 32 mm (1.25 inch)
Rear 32 mm (1.25 inch)
Top 19 mm (0.75 inch)
Federative Republic of Brazil (1974)
Wheeled Reconnaissance Vehicle – 464 Built (M2), 200 Built (M3)
While the EE-9 was still in its pre-production stage, known as the CRM, the Brazilian Army considered arming their new wheeled reconnaissance vehicle with a 90 mm gun in 1972. The 90 mm gun would not only make the Cascavel more capable to fight potential enemies during reconnaissance, it also made the vehicle more appealing for export. Sadly, the debate on how to arm the EE-9 raged for most of the 1970s and it would be foreign countries which gave the needed nudge for the 90 mm armed Cascavel to be created.
While building the pre-production vehicles, Engesa trialed the EE-9 in Portugal in 1973. Portugal was impressed with the platform, but did not like the 37 mm cannon with which all the Cascavel prototypes were armed up to that point. The Portuguese suggested rearming the platform with the gun and turret combination of the French Panhard AML-90, known as the H-90 turret. Engesa built a 90 mm armed version and then returned for trials in early 1974. The legendary 90 mm armed EE-9 Cascavel was born, and with it, Engesa’s most successful armored fighting vehicle entered the world stage of wheeled reconnaissance vehicles.
The Road to the EE-9
The first steps towards the EE-9 Cascavel were taken in 1967 with the creation of the Parque Regional de Motomecanização da 2a Região Militar (PqRMM/2, English: Regional Motomecanization Park of the 2nd Military Region). The PqRMM/2 was a group of army automotive engineers gathered to study, develop and produce armored vehicles in Brazil, and were the pioneers of the Brazilian defense industry.
They began with an engine replacement program for the M8 Greyhound and the M2 half-track with diesel engines. With the success of these projects, they continued to the next phase of the program and developed Brazil’s first wheeled vehicle with serial production in mind. The Viatura Blindada Brasileira 1 (VBB-1) (English: Armored Car of Brazil 1) was a 4 x 4 vehicle meant for reconnaissance and mounted a copy of the M8 Greyhound’s turret.
Although the VBB-1 seems to have successfully performed its tests when the vehicle was presented to the Army in 1969, the Army did not want a 4 x 4. It was briefly considered by the engineers to cut the hull in half and lengthen it to accommodate a 6 x 6 suspension, but the idea was almost immediately rejected, as the development of a new vehicle was deemed more effective.
The first mock-up of the new 6×6 was known as the Viatura Blindada de Reconhecimento 2 (VBR-2, English: Armored Reconnaissance Vehicle 2). The VBR-2 was pretty much a Brazilian copy of the M8 Greyhound and it was armed with a 37 mm cannon and a .50 cal machine gun. A single metal mock-up of the VBR-2 was made by the PqRMM/2 in early 1970.
The VBR-2 mock-up underwent various redesigns together with a redesignation to Carro de Reconhecimento sobre Rodas (CRR) (English: Wheeled Reconnaissance vehicle). The hull underwent some geometric redesigning compared to the VBR-2, causing the vehicle to look less like a box because of the more angled side plates. Another difference in the hull design, which enabled the hull to receive an improved ergonomic design, was the redesign of the driver’s raised hull construction.
Another important step in the development of the CRR was the installation of the Boomerang suspension from Engenheiros Especializados SA, better known as Engesa. Engesa had previously modernized and delivered new trucks for the Brazilian Army with their Total Traction system. This patented traction system was the key for Engesa in the defense industry, mainly because it was identified as a system ‘of interest to National Security’ by the Army. Engesa also participated in the VBB-1 project by supplying the transfer box.
With the installation of the Boomerang suspension and the redesign of the hull, the basis was laid for what would become the EE-9 Cascavel. The mock-up of the CRR was built in early 1970 and presented to General Plínio Pitaluga, a veteran of the FEB (Força Expedicionária Brasileira, Brazilian Expeditionary Force). It seems that, almost immediately after the mock-up was finished, the PqRMM/2 engineers started the production of the first working prototype. The prototype of the CRR was completed in 1971. It used a copied and redesigned M8 turret, armed with a 37 mm cannon and a .50 machine gun on the roof. The turret was fully enclosed. The vehicle-mounted run-flat tires had previously been developed by Novatracão for the VBB-1 project.
The CRR was extensively tested by the Brazilian Army and overseen by the PqRMM/2. The tests were successful, as the construction of a 5 vehicle pre-series was approved. This increased to 8 vehicles after the Diretoria de Pesquisa e Ensino Técnico do Exército (DPET) (English: Army Directorate of Research and Technical Education), which oversaw the PqRMM/2 developments, signed a contract with Engesa in June 1971 for the development and construction of the pre-series. Production began in 1972 and was finalized in September 1975.
With the signing of this contract, the CRR was officially carried over to Engesa. What is interesting is that the Brazilian Army, despite having developed the CRR, signed off all their intellectual property rights to Engesa. This effectively meant that the Brazilian Army itself would not directly profit from any sales of the future EE-9 Cascavel to other countries. This transfer to Engesa also meant that the CRR would be marketed as the EE-9 Cascavel.
Engesa
Engenheiros Especializados SA, or Engesa, was the largest and the most famous company in the Brazilian armored vehicle industry. Engesa was founded in São Paulo in 1958 by José Luiz Whitaker Ribeiro. Initially, Engesa focused on oil prospecting, production, and refinement equipment. With the invention of Engesa’s Total Traction suspension system, they were hired to modernize and build trucks for the Brazilian Army.
In 1969, Engesa introduced its flagship Boomerang suspension for its wheeled vehicles. Only a single axle was needed to drive the 4 wheels which were in continuous contact with the ground, providing constant traction. At the time, this was a simple, sturdy, and relatively cheap construction. Although not fit for heavy vehicles, it was perfect for the armored vehicles that Engesa would start to manufacture in the near future.
With Engesa’s involvement in refitting the Army’s trucks with the Total Traction system and the development of their Boomerang suspension, they were contacted by the Army to help develop the wheeled vehicles together with the PqRMM/2 team. This joint development resulted in the EE-9 Cascavel and the EE-11 Urutu. The EE-9 Cascavel paved the way for Engesa to take its position as the leading company of the Brazilian defense industry.
The Snake Family
The EE-9 Cascavel was part of a family of wheeled vehicles, all named after snakes found in Brazil. These vehicles were the EE-3 Jararaca, EE-9 Cascavel, EE-11 Urutu, and EE-17/18 Sucuri, meaning jararaca, rattlesnake, crossed pit viper, and anaconda, respectively.
The EE-3 was a 4 x 4 reconnaissance vehicle which could mount a wide range of turrets. The EE-9 was also a reconnaissance vehicle, but due to its mobility and the 90 mm cannon, it would be employed in all kinds of roles. The EE-11 was a troop transport, but could be configured to perform all sorts of specialized roles, such as anti-aircraft, mortar carrier, and ambulance. The EE-17 and EE-18 Sucuri were two 105 mm armed 6 x 6 wheeled tank destroyers.
The EE-9 was effectively the flagship of this family, even though Engesa thought the EE-11 would be their most successful vehicle. The EE-11 was successful nevertheless, but the Jararaca and the Sucuri were less of a success. The Jararaca was sold in very limited numbers, while the Sucuri was not even sold at all.
Cascavel Designations
With the transfer of the CRR to Engesa also came a new designation. The exact date of when the CRR was designated as EE-9 is unknown. But it is estimated to have been renamed between 1972 and 1973, with EE referring to Engenheiros Especializados (English: Specialized Engineers) and the 9 to its weight in tonnes. The interesting part is that practically every Cascavel exported by Engesa weighed more than 10 tonnes empty. As such, the 9 in EE-9 refers to the 37 mm version of the Cascavel. The weight in a brochure, which is estimated to have been written between 1973 and 1974, refers to the Cascavel with a 37 mm gun as having a 9 tonnes combat weight.
The CRR was redesignated by the Army as well, with the completion of the pre-production batch, to Carro de Reconhecimento Médio (CRM) (English: Medium Reconnaissance Car). This designation is more of a vehicle classification, like the CRR, than a name. This effectively means that the prototype CRR, the pre-production CRM, and the production vehicles were all known and sold as EE-9s.
What is interesting is that Engesa seems to have skipped designating an M1 Cascavel and immediately built M2 hulls after the CRM. It might be that the 37 mm Cascavels were unofficially seen as first production versions, but through hull classification were simply branded as M2s.
Since the EE-9 Cascavel was built and developed for 18 years, it received upgrades and design changes over time. To keep track of these changes, a so-called Modelo or Model system was used. It is important to note that different guns or turrets did not determine a different Cascavel model. The Cascavel M2 for example, used two 90 mm turrets offered by Engesa (HS-90 turret with the French D-921 gun and the ET-90 I turret with EC-90 gun). It was mainly changes to the hull, and especially the transmissions, which caused the Cascavels (Portuguese: Cascavéis) to be classified as a certain model. The Modelos were then further subdivided in production batches or Séries. The differences between the series could be as small as different bolts or different tyre nozzles. The development of the Cascavel was an evolutionary process, and certain manuals would be written specifically for a range of series of a certain model.
The enthusiast’s guide to Engesa’s Cascavel galaxy
Model
Characteristics
Date
Number sold by Engesa
CRM
The pre-production EE-9 with a manual Clark 280V transmission and a 37 mm gun, practically an improved M8 Greyhound.
1971
8
EE-9 M2
Interestingly, Engesa seems to have skipped designating a Cascavel with the M1 designation. As a result, the production Cascavels with 37 mm guns are also M2’s.
The first EE-9 to have a 90 mm gun as its main armament. Overall hull redesign, larger dimensions of the hull to mount the new 90 mm armed turrets. Used a manual Clark 280V Transmission
1974
Brazil: 157 of which at least 9 were originally armed with 37 mm.
Bolivia: 24
Chile: 83
Libya: 200
EE-9 M3
Effectively an M2 Cascavel, but with an automatic MT-540 transmission (the first Cascavel model with an automatic transmission). The first Cascavel model to receive the EC-90 gun.
1975
Libya: 200
EE-9 M4
The M4 was specifically designed, built and sold with the Detroit Diesel 6V53 engine. Overall strengthening of components and further evolution of the hull design. It used an MT-643 transmission.
1979
Brazil (CFN): 6
Colombia: 128
Cyprus: 124
Iraq: 364
EE-9 M5
Used the M4 design but was a cheaper version. It was sold with either an AT-540 or AT-545 transmission in combination with the OM-352A engine.
1981
Bovington Tank Museum: 1
Gabon: 14
Uruguay: 15
EE-9 M6
Automotive enhancements over the previous models. Used the AT-545 in combination with the OM-352A engine.
1982
Brazil: 37
EE-9 M7
The same as the M6, but used an MT643 transmission. This Cascavel was the final model designed by Engesa. It could mount every engine which Engesa sold with the Cascavel, although it only seems to have been used with the OM-352 and the OM352A engines.
Total: around 1,742 sold and less than 1,800 produced.
Arming the EE-9 Cascavel
In 1972, with the start of the construction of the pre-production Cascavels, came the discussion of what the future reconnaissance vehicles of the Brazilian Army should be armed with. Up until then, reconnaissance doctrine of the Brazilian Army had not changed since their experiences in World War 2, and this old doctrine was still somewhat ingrained in the Army.
An analysis regarding the specifications for a reconnaissance vehicle was released on July 10th 1967. The requirements called for a vehicle which could penetrate its own armor at ranges up to 1,000 m, fire in all directions (have a turret), a rate of fire of at least 3 shots per minute, and the armament did not have to be used for anti-aircraft purposes. The issue with these requirements was that practically every gun of 20 mm and larger could perform this job.
With the initiation of the VBR-2 project, a discussion emerged within the Army. Recommendations were gathered on what to arm the coming generation of reconnaissance vehicles with. The issue was that the Armies (plural) of Brazil, generals, and departments gave conflicting advice. Aside from this, the Army also had to take export potential into consideration for Engesa. Since the Brazilian Army completely handed over the project to Engesa, they also wanted to keep logistics and profit for the company as advantageous as possible. By the end of 1972, the Brazilian Army had selected two ranges of potential cannons: 20 to 40 mm or the 90 mm. The Army referred to the FV107 Scimitar for the lower caliber cannons, potentially suggesting that they wanted an autocannon on the Cascavel, and not the 37 mm which they had used so far.
With the selection of the two ranges, a new discussion came at the forefront regarding the purpose of the reconnaissance vehicle. It was recognised that less than 4% of the missions performed by cavalry units during World War 2 were pure reconnaissance missions. The question then was which role would the future Cascavel perform the most and which of these guns was the most suitable. The 90 mm would perform best for anti-tank missions, while the 20 to 40 mm range would be more fit against personnel and overall perform an infantry fighting vehicle role, without being able to carry infantry. It was identified that the EE-9 would not be fit to fill the Infantry Fighting Vehicle (IFV) role as it lacked the needed armor. At the same time, it was recognised that a 90 mm gun would give the Cascavel a better fighting chance against potential enemy armor. The reasoning came mainly from an isolation point of view, in which a Cascavel on a reconnaissance mission had to fend for itself and take out potential enemies, such as tanks. It was determined that the 90 mm was the most suited for this role, considering most of Brazil’s neighbors operated the Shermans as their heaviest armored vehicles at the time, and employed a large number of light AMX-13s and SK-105s as their other combat tank.
It took up to the second half of the 1970s for the Brazilian Army to completely make up its mind on which cannons should be used on the Cascavel. When this discussion still raged in 1977, the Cascavel with 90 mm gun was already used by Libya against Egypt, and multiple countries ordered the 90 mm cannon. What might have steered the Brazilians towards eventually deciding to solely operate a 90 mm Cascavel force were the trials in Portugal in 1973.
Armoring the EE-9 Cascavel
Until 1968, armor studies were practically non-existent in Brazil. There had been some brief attempts during the revolutions of 1924, 1930, and 1932, but these were mainly of improvised nature. With the initiation of national armored vehicle development also came studies on what to armor the upcoming armored vehicles with. The PqRMM/2 team started off by evaluating all the steel compositions of the vehicles which were acquired by the Brazilian Army over time. The team discovered that the homogenous steel plate of the M2 Half-Track had been heat-treated on the outer side to provide a harder surface, while providing a more ductile surface on the inside to prevent shattering.
The team determined that the effort needed to carry out the necessary techniques for hardening was only justifiable for mass production. With mass production of the future armored vehicles being expected, the team decided that the development of a dual-hardness plate or bimetal armor would be viable. This type of steel was previously developed in Sweden in 1930 and was known as duplex steel. It would find its first extensive usage on armored vehicles in Brazil. The main difference from other examples of face hardened armor is that two plates of varying carbon content were welded together in production to form a bimetal plate instead of bolting on a hardened plate afterward.
The steel for the bimetal plates was provided by Eletrometal and Usiminas. With Eletrometal providing the high-carbon outer plates and Usiminas the medium-carbon plates. The plates were joined, with 25% of the total plate thickness being high-carbon steel and 75% medium-carbon. The plates were laid on top of each other and subsequently welded around the edges. The bimetal plates were then forged together from 65 mm to about 30 mm thickness and then hot-rolled to the required thickness. This was followed by a quench, tempering, and hardening to the desired hardness. The high-carbon plate was hardened to 700 Brinell while the medium-carbon plate was 250 Brinell.
The average effectiveness of the bimetal plates was about 1.8 times the thickness of an equivalent homogeneous plate against 7.62 mm or 1.5 times the thickness against .50 machine gunfire. This meant that, against .50 machine gun fire, a 16 mm bimetal plate could be used instead of a 25 mm homogenous steel plate. These protection advantages over homogenous plates effectively meant that the Cascavel saved a lot of weight without compromising protection. The outer layer would shatter and blunt the incoming projectile, while the inner layer would relatively move with the bullet, slowing it down and stopping it without shattering.
An interesting tidbit of information according to an ex-Engesa employee who worked at the tempering station was that, at some point, the armor did not perform according to standards. It turned out that the tempering oven was not maintained properly, and the temperature control was faulty. This issue would remain for a few years until it was finally resolved. In order to keep building the armored vehicles, a lot of these plates were approved by quality check anyway, despite being faulty.
From Former Colony to Colonizer to Former Colony
In early 1973, Engesa trialed their vehicle in Portugal in an attempt to export them. Portugal was fighting uprisings in its colonies in the War of Ultramar, also known as the Overseas War in English. At the time, the Portuguese Army was operating a mix of AML-90 and Panhard EBR armored cars in Africa.
The Portuguese were impressed by the EE-9 Cascavel, which at that time was most likely still in its CRR configuration, but they suggested that Engesa should arm the Cascavel with the same turret and gun as the AML-90 and return to trial the vehicle again. The platform of the EE-9 was good, but its 37 mm armament was outdated and not competitive with what Portugal already had.
With Engesa wanting to arm the Cascavel with a 90 mm gun, the Brazilian Army opted to go for the 90 mm gun on the X1 project as well. They bought 53 turrets and guns from the French company SOFMA. Most of these turrets were ditched by the X1 program, as they did not meet the protection requirements of the Brazilian Army, and local turrets were designed (based on the HS-90 turret of the AML-90) and built as a result. The reason why the Brazilians did not just buy the guns if they were going to ditch the turrets anyway, was because the French company SOFMA refused to sell the gun independently from the turret. Engesa would arm the EE-9 sent to Portugal with the French turret, but also developed their own turret.
The EE-9 in Portugal was trialed again in early 1974 together with an EE-11 Urutu. The EE-9 probably had the eventual production variant hull design to solve some practical issues of the CRR and CRM configuration and mounted an HS-90 turret,armed with a D-921 90 mm gun. This EE-9 trialed in Portugal could be officially counted as being the first EE-9 M2 Cascavel with a 90 mm gun. But so far, no pictures have been found of the Portuguese trials to definitively prove which exact prototype was sent and how it looked.
The problem is that a number of designs were made before pictures of the actual production variant of the EE-9 appear. For this reason, it is uncertain what the exact vehicle looked like, although Paulo Bastos, the Brazilian author and leading expert in the field, stated it was the EE-9 M2 with 90 mm production version. Portugal would not acquire the EE-9 M2 because of a coup d’etat in the country on April 25th 1974, which also put an end to the War of Ultramar.
The influence of Portugal in the success of the EE-9 should not be understated. After the failed attempt to sell the EE-9 Cascavel to the Portuguese, the Engesa team loaded the Cascavel and Urutu back in their freighter and set course to Libya. There, the EE-9 M2 would find success and manage to secure a deal for 200 Cascavels. This deal brought the necessary cash for Engesa to buy a large production plant, and by 1975, the first production Cascavels started rolling from the production line. In 4 years, Engesa had sold the EE-9 M2 and M3 with the 90 mm gun to 4 countries, including Brazil, for a total number of 655 Cascavels.
The request of the Portuguese to arm the EE-9 with a 90 mm gun effectively helped Engesa to secure a deal with Libya, which used the Cascavel in combat, generating more sales and making the Cascavel the success it was. At the same time, Brazil also started the development of locally produced turrets for the 90 mm guns for both the Cascavel and X1.
The 90 mm Turret Designs on the EE-9 and Prototype Hulls
The switch from 37 mm towards the 90 mm would normally mean that the EE-9 Cascavel is an EE-9 M2. A number of projects however, were specifically designed on the early CRR hull or on a hybrid between the CRR and the pre-production vehicle which would be designated as Carro de Reconhecimento Médio (CRM, English: Medium Reconnaissance Car). The problem is that these designs were made before the production vehicle of the EE-9 was built. For this reason, these projects will be seen as prototypes for the EE-9 M2. There were two designs: a CRR/CRM hybrid mounting the copied and lengthened M8 turret and armed with a 90 mm gun and a CRR with the French turret. These designs are thought to have been made after early 1973 and before early 1974. This is because the brochure shows both designs while not showing an actual built Cascavel with 90 mm gun.
The CRR with HS-90 turret
The Brazilians made a design with the CRR hull mounting an HS-90 turret. This design was effectively the predecessor of the EE-9 M2 Cascavel. The HS-90 turret was ordered from France and had to be bought as a full package, including the D-921 gun. This Cascavel would have had a gun depression of 8º and an elevation of 15º. Aside from the 90 mm gun, it was also armed with a coaxial 7.62 mm machine gun and 3 smoke launchers on each rear side of the turret. It could mount a turret top machine gun, night vision sights, radio and intercom, laser rangefinder, and an extra ammunition stowage as optional equipment. It is stated that the EE-9 sent to Portugal used this turret, but it is unlikely that the CRR hull was used for these trials.
The reason for this is that the HS-90 turret would not only be too big for the hull and come in collision with both the driver’s vision structure, but also with the engine bay covers. On top of that, the driver’s vision structure would make it virtually impossible to depress or even fire the gun on a flat angle. As such, it seems that the drive for the 90 mm turret caused the hull to be redesigned to resolve these issues.
The CRR/CRM Hybrid with M8 Copy Turret
Another of the designs was effectively a hybrid between the CRR and the later CRM production vehicle. The main hull design change which hints towards it being a hybrid design is the altered headlight guard. On the CRR, the headlight guard was a simple square design, while in this design, it was curved, like on the CRM.
In addition, the copied M8 turret also received some changes which would be seen in the turret later used on the pre-production CRM. Compared to the original CRR turret, this turret had a ventilation inlet on the top of the turret and the antenna, which was originally on the left rear side of the hull, had now been installed on the turret as well. Apart from these 2 features, the turret also provided periscopes for the gunner, apart from the direct sight in the gun mantlet. The 90 mm gun would have a depression of 8º and an elevation of 13º and be installed in a turret with a turret diameter of 1.6 m. It could mount a turret-top machine gun for anti-aircraft purposes.
In addition, a Perkins type 6357 6 cylinders in-line 142 hp diesel engine, along with a Chrysler type 318 HD V8 196 hp diesel engine, were offered. Engesa also offered to fit in other engines, depending on the customer’s needs. It would use a 6-speed manual gearbox with five forward and one reverse speeds. It would have been protected from the front with bimetal armor, protecting against .50 machine gun fire and from the sides from 7.62 mm fire. The exact weight and speed of this design are unknown but are estimated at around 10 to 11 tonnes and 95 km/h, depending on the engine selected.
The CRM and a Bid for a National Turret
By September 1975, the production of the pre-series of 8 vehicles armed with 37 mm cannons, known as the CRM, was finished. The pre-series hulls still carried over much of the design of the CRR hulls. The CRM can be easily identified and distinguished from the CRR in two ways. The first is the redesigned headlight guards, which were now curved instead of simple squares. The second is the relocation of the antenna and most likely the radio set as well. On the CRR, the antenna was located on the left rear of the hull, while on the CRM, the antenna was moved to the turret.
What makes the CRM complicated with the timeline of the EE-9 M2 with 90 mm gun, is that the CRM still used a number of design features from the CRR which would have made mounting a HS-90 turret practically impossible. It still used the raised driver structure, an external exhaust, and similar engine bay designs. What is thought to have happened is that the design and production of the pre-production batch was already well underway during late 1973 and early 1974, which would cause Engesa and the Army not to change the design of the pre-production vehicles. In addition, the Army had not yet finalized its stance towards the 90 mm gun, so a redesign might not even have been needed at that point.
Another important reason might be that the pre-production design was meant to be the final hull design for the EE-9. This is partially supported by a program in Brazil for a new national turret for the EE-9 for which both Engesa and Bernardini (the manufacturer of the X1 light tank) put forward their designs for the new turret. These turrets are for all intents and purposes the same as the turrets of the X1, with Engesa proposing the X1 turret of the first X1 prototype, and Benardini proposing the X1 production turret, but armed with a 37 mm. These turret designs were of a higher profile than the Hs-90 turret and with these turrets, the 90 mm could depress without collisions with the driver’s structure. It is unknown if Engesa built and offered a 37 mm turret. Both of these proposals were built on CRM hulls.
Bernardini’s Entry
Bernardini would have most likely entered the competition with both the 37 mm turret and the 90 mm turret. The turret which Bernardini offered was the production turret of the X1, which was designated BT-90A1. The Brazilian Army had previously bought 53 HS-90 turrets and D-921 90 mm guns. The issue was that the turret armor of the HS-90 was insufficient for the requirements of the Centro de Pesquisa e Desenvolvimento de Blindados (CPDB) (English: Center for the Research and Development of Tanks). As a result, Bernardini and the Brazilian Army started developing a local turret which was armored with 25 mm thick plates to protect the X1 from .50 cal machine gun fire. The design of the BT-90A1 turret was heavily inspired from the HS-90 turret, with the first prototype of the turret (BT-90) even using some components of the HS-90 turret. The main differences between the HS-90 and the BT-90A1 were the addition of a gun shield on the BT-90A1, improved armor, and the BT-90A1 overall being more bulky than the HS-90. The main difference between the 37 mm and the 90 mm turrets from Bernardini was that the 37 mm turret received a new gun shield and was altered for the 37 mm armament.
Engesa’s Entry
Engesa’s design was almost a copy of the turret from the X1 prototype, also known as a BT-90 turret. The turrets differed in a very minor way. The rear sides of the Engesa turret, on which the most rearward smoke launcher was installed, went inwards instead of being a flat plate. It is unknown if this turret used bimetal armor or not. The vehicle was armed with a 90 mm gun and a coaxial 7.62 mm machine gun. In addition to its armament, the turret also mounted 2 pairs of 3 smoke grenade launchers on both sides of the rear turret.
Who Won?
It is unclear which company won this specific bid, as both the Engesa turret and the Bernardini turrets were never mass-produced. What most likely happened, was the switch from the D-921 gun to the license produced EC-90 gun, which was based on the Cockerill 90 mm Mark 3 gun. In 1975, Engesa got a license deal with Cockerill for their 90 mm gun. This turret design bid was most likely initiated in between 1973 and 1975 and probably ended when Engesa got the license deal in order. It is unclear if a new bid for an ET-90 armed turret was opened, but what is known is that Engesa would design the ET-90 turret which would be used on the Cascavels from that point on.
The First Customers for the EE-9 M2 with 90 mm gun
It might be that the Portugal trials are not only responsible for the 90 mm gun on the Cascavel, but also for the hull redesign of the EE-9 production versions to enable them to mount low-profile 90 mm turrets. If this is the case, then it is very likely that the EE-9 M2 trialed in Portugal is in fact an EE-9 M2 hull as we know it today and is potentially even the first prototype of the production hull for both the EE-9 M2 with 37 mm gun and with 90 mm gun.
In any case, the EE-9 M2 became a success with 200 vehicles being ordered by Libya in 1974. Chile also bought 60 EE-9 M2s in the same year. Bolivia followed suit not too long after with 24 EE-9 M2s, but at what exact date the order was made remains unclear. The exact delivery dates also remain somewhat uncertain, but based on a document from Engesa, Libya was the first country to receive its EE-9s. Sourcing is a bit unclear here as the Engesa document states that the EE-9 M2s were delivered over a 2 year period from 1975 to 1976, in seemingly two batches, while another source seems to suggest that they were delivered in a single lot. In general, the wording of Brazilian sourcing seems to be open to interpretation as it usually states when the vehicles were bought and less when they were exactly delivered. As such, all delivery dates will be based on Engesa documents.
The sale of the EE-9 to Libya also meant that Engesa could take a big step. The order was paid upfront and Engesa used the money to build a large factory in São José dos Campos in São Paulo state to be able to serialy produce the armored vehicles, which was in operation by September 1974. By 1975, Engesa had built its 100th EE-9 and a total of 125 was said to have been delivered to Libya that year. The shipping route from the factory to Libya was quite interesting as well. Considering the EE-9 M2s still used the French HS-90’s, Engesa built the hulls, then shipped the hulls to Toulouse in France where they would mount the turrets. After the EE-9s received the turrets, the vehicles were shipped to Libya.
The Cockerill Gun
Bolivia and Chile received their first EE-9 M2s with the HS-90 turret in 1976 and the orders were completed a year later, in 1977. After the export of the 60 EE-9 M2s with HS-90 turrets to Chile was finalized in 1977, it seems that Chile ordered another batch of 23 EE-9 M2s mounting the new ET-90 I turret with the EC-90 gun. These 23 vehicles were, again, seemingly delivered over a two year period.
In 1975, the first significant design switch was made by Engesa. With 284 EE-9 M2s exported, the French realized that the EE-9 could become a competitor to their own wheeled armored car sales.
Still selling a significant amount of AML-90s at the time and not yet having their own 6 x 6 rendition similar to the Cascavel, the EE-9 could be seen as a better platform than the AML-90. The EE-9 was larger and heavier, but it did offer better mobility through the Boomerang suspension, it offered better armor through bimetal steel plates and it was offered for the same role as the AML-90. In response to the EE-9’s success, the French company SOFMA (which was responsible for the French export sales) recognised that Engesa was dependent on them for building the EE-9s as they had to buy the turrets from SOFMA. It is said that SOFMA started raising its prices to such a degree, that it effectively forced Engesa to look for another option as the HS-90 turret was simply not viable anymore.
Engesa found its solution in Belgium. They acquired the license to produce the low-pressure 90 mm Cockerill 90 Mark 3 gun in 1975 for US$3 million (US$15.5 million in 2021). The gun would be designated EC-90 by Engesa, with the E standing for Engesa, C for Canhão (Cannon), and 90 for the 90 mm gun. This license deal not only made it possible for Engesa to manufacture their own guns, but it also opened the door for them to design their own turrets. In addition, these turrets were also better than the French HS-90 turrets as Engesa incorporated bimetal steel on the turrets as well.
The EE-9 M3 and Recognition
The next step in the Cascavels design was the EE-9 M3. The EE-9 M3 is effectively an EE-9 M2, but with an AT-540 automatic transmission instead of a manual Clark 280V transmission. As such, it is practically impossible to tell an M2 from an M3 from the outside. The only way one could properly distinguish an M2 from an M3 is by going inside the vehicle and looking at an Engesa ID plate to read what kind of gear shift it uses. Considering there seem to be no interior pictures of the supposed EE-9 M3, we have to rely on Brazilian sourcing stating that they were M3s until photographic evidence of those two specific details for what is thought to be an M3.
Using evidence from EE-9s in service with African states, M2 and M3 hulls can be distinguished regardless of the turrets installed. It seems that only the M2 hulls received steel ridges on the front hull to give the crew extra grip, while the M3 hulls received an anti-slip surface instead. Another detail is the rear light configuration. The M2 uses two lights which are next to each other horizontally, while the M3 uses two lights installed vertically. Sadly, the steel ridge detail does not completely hold up for any later modifications to the vehicle as some modified M3 Cascavels appear to have received them on pictures during the Libyan Civil War. In any case, the rear light and anti-slip recognition methods seem to be the most reliable to distinguish M2 and M3 hulls in Africa, regardless of the HS-90 or ET-90 I mounted turrets.
The M3 was the first Cascavel to have an automatic transmission, it was the first to be armed with the 90 mm Cockerill gun in the newly designed ET-90 I turret from Engesa, and it seems to have been the first EE-9 to have received a laser rangefinder. The E of the ET-90 I stood for Engesa, T for Torre (turret), 90 for the armament, and I was added later as Engesa redesigned the first ET-90 turret which would be known as the ET-90 II. It is important to note that the turrets of the Cascavel do not necessarily indicate the model of the EE-9, as the EE-9 M2 has mounted two of the three 90 mm turrets (all but the ET-90 II).
That being said, the EE-9 M2 and M3 do have an exception to this rule. The EE-9 M2 is the only Cascavel hull to have officially mounted the French HS-90 turret and the EE-9 M3 has only officially mounted the ET-90 I turret. A reason for the EE-9 M3 to have only officially used the ET-90 I turret, is because the M3 was only sold to Libya. However, there is proof that Libya and potentially other countries operating the M2 and M3 vehicles have switched around the turrets at some point on a number of EE-9s. The next customer after Bolivia, Chile, and Libya was Iraq in 1979. At this point, the EE-9 hull had received significant redesigns by Engesa and was known as the EE-9 M4.
The Cascavels’ Finest “Hour’’?
In 1977, the Cascavel supposedly proved itself in combat between the Egyptians and Libyans. From July 21st to 24th Egypt and Libya were engaged in a four day border war, later known as the Egyptian-Libyan War or the Four Day War. Preluding the war, clashes between the two sides intensified on July 12th, 16th, and 19th. Supposedly, during one of these clashes or raids, the Cascavels reached the front much quicker than the other vehicles of the Libyan Army and managed to take out an Egyptian T-55.
It is quite likely that this supposed success happened either at the start of the war or before it, as the Libyan Army was, for all intents and purposes, outclassed and outnumbered by the Egyptian Army. The war ended with a truce although hostilities remained. The success of the Cascavel is thus likely to have been before the war began where its reputation would be less spoiled by the subsequent failure of the Libyan Army.
It is somewhat complicated to properly verify if this statement of the EE-9’s performance in Libya is true, as international press was barred from the conflict zone, leaving reliable information and pictures of the conflict to be desired. If Brazilian sourcing is to be believed, the Cascavel’s remarkable performance caused more countries to take note of the armored car and would end up in more sales for Engesa. How far this is actually the case can be somewhat questioned, as the first order for the EE-9 made after the war was done by Iraq in 1979, and all other orders came after 1980.
Brazil Gets the EE-9 M2 with 90 mm gun
When Brazil started operating the EE-9 M2 with a 90 mm gun remains a mystery. According to Paulo Bastos, writer for Tecno Defesa and one of the leading experts on Brazilian vehicles, Engesa did deliver a significant number of turretless Cascavels to the Brazilian Army during the 1970s. Refraining from unnecessarily mounting outdated turrets would save the Army a significant amount of money later down the road when they did make a decision. This would not be strange as the Brazilian Army seems to have still discussed the armament for the Cascavel until at least June 1977, considering a 90 mm or an autocannon ranging from 20 to 40 mm.
It might even be after 1978, as a picture shows that at least 9 37 mm armed EE-9s participated during the September 7th parade of 1978, suggesting that the Cascavels were not yet rearmed. In addition, a single EE-9 M2 armed with a 90 mm also appeared during that parade, but it mounted the French HS-90 turret and not the ET-90 with the Cockerill gun.
A Deputy Chief of the Brazilian Army suggested the production of the X1A2 light tank in July 1978, which would be armed with the EC-90 to better standardize ammunition with the EE-9s. It is thus a distinct possibility that the eventual choice to arm the Brazilian Cascavels with the EC-90 gun was made sometime between June 1977 to July 1978.
This might be further supported as the first batch of 148 EE-9 M2s delivered until 1978, all used the same parts catalog, while an additional 9 EE-9 M2s delivered in 1980 fell under a new catalog. This time gap might suggest that in between 1978 and 1980, the Brazilian Army made its choice and initiated the arming and rearming of the EE-9s with the ET-90 I turrets.
This theory is also further corroborated by a maintenance manual for an M2 Cascavel from the Brazilian Army with the designation MM 022 06 79. This manual shows a Cascavel M2 with a HS-90 turret, but with the D-921 gun having a “photoshopped’’ EC-90 muzzle brake instead. The appearance of a manual for a 90 mm armed EE-9 Cascavel seems to suggest an official incorporation of the vehicle within the Brazilian Army.
The writer thinks that the MM 022 06 79 designation means Manual de Manutencão of the date 22-06-79 or June 22nd 1979. This thought seems to be further supported with a Colombian operational manual for the EE-9 with the designation 09682, of which 1982 would be the year when Colombia received their Cascavels. Another Brazilian manual with the designation of 12782 for the M6 Cascavel also points toward 1982, which is the year the Brazilian Army received a number of M6 Cascavels.
The website Armas Nacionais does claim to have a more specific date on when the Brazilian Army received their first 90 mm EE-9s and on how many. According to Armas Nacionais, the Brazilian government signed a contract with the Army after the delivery of the initial 102 EE-9 M2s for the rebuilding of 60 EE-9 M2s in 1976. This does line up with the order/delivery dates of these 102 EE-9s. The first batch of EE-9s with 90 mm guns arrived in 1977 and another batch of 46 EE-9 M2s was ordered in the same year. In 1980, the Brazilian Army ordered another 9 EE-9 M2 Cascavels, making the total number of 90 mm armed EE-9 M2s operated by Brazil at 115.
The dates and numbers mentioned do line up with when the Cascavels were ordered and delivered by other sourcing, but these sources do not specifically mention when these conversions were carried out, nor when Brazili received their first batch. In addition, the writer has been unable to confirm the story from Armas Nacionais with the sourcing used in their article.
All in all, the Armas Nacionais explanation is not a bad explanation with the numbers and dates lining up. Sadly, no other source so far confirms this. Another strange detail is that this would mean that a total of 42 EE-9s would remain unconverted unless these were converted at a later date. Regardless, it is clear that the Brazilian Army lists a total of 157 EE-9 M2s of various series in their service and that the arming of them with the 90 mm seems to have begun somewhere in between 1976 to 1979.
The EE-9 M2 and M3 in Detail
The EE-9 M2 with 90 mm gun weighed 10 tonnes empty and 11 tonnes combat-loaded (11 and 12.1 US tons respectively). It was 6.22 m (20.4 feet) long including the gun and 5.19 m (17 feet) without the gun. It was 2.59 m (8.5 feet) wide and about 2.3 m (7.55 feet) tall with the HS-90 turret. The EE-9 had a crew of three, consisting of the commander/loader (turret left), gunner (turret right), and the driver in the middle front hull.
Hull
The hull of the EE-9 M2 was manufactured from welded bimetal steel plates. The upper front plate was well angled at 60º from vertical. The hull also featured two covers which were mounted on the hull at the positions above the Boomerang suspension, effectively functioning as mudguards and very minor spaced armor.
The front upper hull plate presented 16 mm (0.63 inch) of bimetal armor at an angle of 60º. The sides and rear were 8.5 mm (0.33 inch) thick at varying angles, and the top and bottom hull were 6.5 mm (0.26 inch) thick. The front of the EE-9 was meant to protect from .50 machine gun fire at an unknown range, while the entire vehicle was protected from 7.62 mm AP rounds at 100 m (109 yards), and standard 7.62 mm rounds at 50 m (54 yards).
The EE-9 had two headlights externally mounted on top of both sides of the upper front hull plate. A rearview mirror could be mounted on both headlight guards. A black-out light was installed on the right side of the left headlight. Below the driver’s hatch was a foldable windshield, which the driver could use when driving with an open hatch. The driver’s hatch was a two-piece hatch, with the front part being part of the upper front plate, while the back part was part of the top hull plate. The front hatch had three periscopes for the driver for 180º of vision. Interestingly, the Libyan EE-9’s only had 1 periscope. These periscopes and other periscopes or sights would not have been active or passive night vision equipment unless the Cascavel was ordered with these devices. The standard periscopes were manufactured by D.F. Vasconcellos.
It is interesting to note however, that all the Libyan EE-9s (M2s and M3s) use a single driver’s periscope. It is unknown why this was done, as the three sight EE-9’s were already around at the time. It might have been to save money or the Libyans might simply not have seen the use of the extra periscopes providing a larger view arc.
A ventilation inlet was installed on both upper hull side plates, these ventilation inlets are recognizable by their frustum shape. A siren was installed behind the ventilation inlet on the right side of the vehicle. The fuel tank cap of the Cascavel was located on the left side, in the middle of the upper side hull plate, with the fuel tank installed on the hull floor. The EE-9 had a large ventilation grille on the rear of the vehicle, reminiscent of the M8, and had a rear light on both sides of the ventilation grill. The engine could be accessed through two large hatches on the hull top rear.
The M2 used an adjustable hydraulic powered steering wheel for steering and had 3 pedals: the clutch for gear shifting on the left side of the steering wheel, the brake on the right side of the steering wheel, and the throttle to the right of the brake. The gear shift stick was located to the right of the driver. A control panel was located on the front left of the driver for, among other things, the headlights, siren, windshield, and interior lighting. The dashboard was located to the right which included a speedometer, ignition switch, fuel meter, and temperature meter among other things.
What the driver’s station on the M3 looks like is unknown, but it is thought to be fairly similar to the stations of later Cascavels which use automatic transmissions. This would mean that the gear shift stick was replaced with a gear selector stick and the clutch pedal was removed. In essence, both the M2 and M3 are essentially driven like cars.
Mobility
The EE-9 M2 used the OM352 and the OM352A engines, while the M3 only used the OM352A engine. These are both 6-cylinder inline diesel engines of which the OM352A is turbocharged. The OM352 produces 125 hp at 2,600 rpm and 353 Nm at 1,600 rpm, while the OM352A produces 172 hp at 2,800 rpm (DIN standard) and 431 Nm at 1,800 rpm. The Brazilian Army seems to have only used the OM352A engine, although it is unknown if early Brazilian Cascavels might have received the standard OM352 engine to be rebuilt or replaced later on. Libya is the only country to have operated the OM352 with certainty in their first 200 EE-9 M2 Cascavels, the other operators only used the OM352A.
The M2 Cascavel had a top speed of 95-100 km/h (59 mph) and an operational range of 750 km (466 miles). It had a turning radius of 7.7 m (8.1 yards) and it could ford a depth of 1 m (3.3 feet). The Cascavel could climb a 35º slope, could climb a vertical obstacle of 0.65 m (2.1 feet), cross a 1.65 m (5.4 feet) trench, and had a ground clearance of about 0.5 m (1.6 feet). The front-wheel could travel for 0.2 m (0.66 feet), while the rear wheels could travel for 0.9 m (3 feet). It used 12 X 20 run-flat tires with a diameter of 0.5 m (1.6 feet). The EE-9 M2 had a distance between the front axle and rear axle of 2.8 m, and a distance of 1.4 m (4.6 feet) between the two rear wheels.
The EE-9 M2 used a manual Clark 280V transmission with 5 forward and one reverse gears. The EE-9 M3 used an AT-540 automatic transmission instead, with 4 forward and one reverse gears. The automatic transmission would make the vehicle much easier to drive and significantly reduced the chance of misshifts in stress situations.
In addition, the Cascavel used an Engesa 2 speed transfer case, which allowed the Cascavel to be used in reduced and high gear. By putting the Cascavel in reduced gear, horsepower was sacrificed for an increased torque, making it more effective in climbing slopes. The vehicle was 6 x 6 driven, of which the rear 4 wheels were part of the Boomerang suspension. The Boomerang suspension, in combination with the Engesa 2 speed transfer case, enabled the Cascavel to cross challenging terrain and provide maximum traction in most situations.
The power of the engine was distributed to a differential on the front side of the vehicle, and a differential in the rear. The rear differential drove the Boomerang suspension with a single axle, which made the Boomerang suspension such an ingenious design.
In 1969, this suspension was invented by Engesa to enable trucks to transport oil to the refineries through rough terrain with bad infrastructure. With this suspension, the trucks could traverse otherwise untraversable hills for conventional suspension systems, as the wheels would always stay in contact with the ground to provide maximum traction.
The suspension system was a two wheeled-single axle driven suspension. The advantage of the Boomerang suspension was that it could be fitted on existing differentials with a single axle. Normally, this meant that the single axle, designed for the torsion forces of a single wheel, was subjected to the torsion forces of two wheels. Through excellent engineering, half of the torsion forces of the two wheels were mitigated by the suspension system built around the original axle. This design not only enabled the drive of two wheels by a single axle but with clever usage of gears and bearings on both the axle and tube around the axle, the suspension system can rotate around its axle for 360º. This ability to rotate in extreme angles would enable the vehicles to traverse very difficult terrains and still provide maximum traction, as the suspension system curved with the terrain so that all the wheels were always in contact with the ground.
The Boomerang suspension used leaf springs for dampening. The two front wheels were used for steering. The wheels on the Boomerang suspension all rotated at the same speed. The front wheels were dampened by large coil springs. The vehicle used hydro-pneumatic drum brakes, and was steered with hydraulics as well.
A Central tyre Inflation System (CTIS) was also offered by Engesa for the EE-9 M2 and M3, but it is unknown if any if the M2s or M3s were sold with this system. The Brazilian Army does not seem to have the CTIS on the M2 or many of their other EE-9s either.
Turret
The EE-9 M2 used both the HS-90 and the ET-90 I turret, while the M3 officially only mounted the ET-90 I turret, although turrets seem to have been switched around on a number of different vehicles in Libya. The HS-90 was the imported turret and the ET-90 I was the locally produced turret and essentially a redesigned HS-90 turret. It shared many concepts and had a fairly similar design. The main difference between the two were armament and materials, as the ET-90 I used both a Cockerill gun and bimetal armor, making it the superior turret.
The Brazilian Army only officially operated the ET-90 I turret on the EE-9 M2s, although a single vehicle in Brazilian markings with the HS-90 turret was shown on the September parade of 1978.
HS-90
The HS-90 turret was manufactured from steel plates welded together. The turret’s armor ranged from 14-15 mm frontally to 7-8 mm in the rear. It was manned by a two-man crew, with the commander/loader on the left and the gunner on the right. The commander’s position can be easily recognized by the dome-shaped cupola. Both crew members had their own hatch, which opened to the rear.
The cannon was aimed with a direct sight telescope coaxial to the gun with 6x magnification. The commander and gunner each had access to 4 sights, all with 1x magnification. A laser rangefinder could be installed on top of the gun shield if requested, although this never seems to have been done on the HS-90 turrets for the EE-9. The turret also had a spotlight on the left front side of the commander’s hatch. A ventilation inlet was located on the top of the turret on the rear.
The turret stored 24 rounds of 90 mm ammunition, of which 12 rounds on the left side of the turret bustle and another 12 rounds in two 6 round-revolver style magazines behind the gunner and the commander. The turrets stored 2,000 rounds (10 boxes) for the 7.62 mm coaxial machine gun, of which at least 6 were stored in a magazine in the frontal part of the turret basket floor.
The turret had a gun depression of -8° and an elevation of +15°, a mechanical drive system and an electrical system functioning on 24 V. It also had 6 76 mm smoke launchers, of which 3 on each rear side of the turret. A roof-mounted 7.62 mm anti-aircraft machine gun, active or passive night vision sights, and laser rangefinder were offered as optional equipment for the turret by Engesa.
ET-90 I
The ET-90 I turret was manufactured by Engesa from a welded bimetal steel plate structure. The turret was armored with 16 mm thick plate allround except for a 8 mm thick plate on the top. It was manned by a two-man crew, with the commander/loader on the left and the gunner on the right. The commander’s position can be easily recognized by the dome-shaped cupola. Both crew members had their own hatch, which opened to the rear.
The ET-90 I turret is, for all intents and purposes, a simplified copy of the HS-90 turret, but superior. It is very likely that you could put the crew from an AML-90 into an ET-90 I turret, and they would be able to operate the turret with the same efficiency from the start, except for having to adjust for the increased muzzle velocities of the EC-90 (license produced Cockerill Mk.3) main gun. This decision not only made it easier for Engesa to produce the turrets and save in development time, it also made it easier to market to countries already operating HS-90 turreted vehicles looking for a replacement. This makes sense considering the HS-90 turret is one of the most widely used turrets on armored cars in the world.
The ET-90 I is a wider turret than the HS-90 in order to simplify its design, sacrificing turret profile for simplicity. At the same time, it could be argued that the larger profile might offer more effective turret ergonomics for the crew and that the usage of bimetal steel compensates for the larger turret profile as well, as it is more effective than monosteel. A clear example of the simplified construction are the commander and gunner hatches. Where the HS-90 had a structure welded to the turret sides with sights integrated in them, Engesa simply widened the turret so they could use a single plate and would not have to make use of such a structure.
The cannon was aimed with a direct line-of-sight telescope from D.F. Vasconcellos coaxial to the gun with 6x magnification. The commander and gunner had access to 4 sights manufactured by D.F. Vasconcellos, all with 1x magnification. These periscopes gave an instantaneous 46° horizontal and 9° vertical field of view, and a total 55° horizontal and 18° vertical field of view. The turret also used a spotlight on the left front side of the commander’s hatch, although this did not seem to be common practice. A ventilation inlet was located on the top of the turret on the rear.
The turret stored 24 rounds of 90 mm ammunition, of which 12 rounds on the left side of the turret bustle and another 12 rounds in two 6 round-revolver style magazines behind the gunner and the commander. The turrets stored 2,000 rounds (10 boxes) for the 7.62 mm coaxial machine gun, of which at least 7 were stored in a magazine in the frontal part of the turret basket floor and 1 next to the gunner.
The turret had a gun depression of -8° and an elevation of +15°, a mechanical drive system and an electrical system functioning on 24 V. It also had 6 smoke launchers, of which 3 on each rear side of the turret. A turret top mounted 7.62 mm anti-aircraft machine gun, active or passive night vision sights and laser rangefinder were offered as optional equipment for the turret by Engesa.
Armament
The EE-9 M2 used both the French DEFA D-921 90 mm low pressure gun and the license produced EC-90 gun, while the EE-9 M3 only officially used the EC-90. The EC-90 had a number of advantages over the D-921 gun. The first was increased muzzle velocity from 750 m/s to 890 m/s for the HEAT (High Explosive Anti-Tank) round. This meant that the projectile had a flatter trajectory making it more accurate and it allowed the Cockerill gun to engage targets at longer ranges.
The other slight advantage was ammunition variety. The EC-90 had access to HESH (High Explosive Squash Head) rounds and Engesa attempted to develop an APFSDS (Armor Piercing Fin Stabilized Discarding Sabot) round in the mid-1980s. The latter round was never finalized however and remained a prototype batch.
The APFSDS performance was more or less on par with that of the HEAT round. It would have provided a muzzle velocity of 1,176 m/s if Engesa had finished its development. Engesa had also started development of a canister round which was never finalized either. In any case, the development of the APFSDS and canister rounds were only initiated around the mid-1980s, when the M2 and M3 Cascavels were no longer in production anymore. The final advantage of the EC-90 over the D-921 is that Engesa could license produce it instead of having to buy both the gun and turret.
The main advantage the D-921 gun had over the EC-90 is that the D-921 was sold with the OCC 90-62 HEAT round. The OCC round had a penetration of 320 mm against the 250-260 mm of the NR478 of Engesa. The exact reason for this rather large disparate performance is somewhat unclear. Considering France had significant experience with HEAT ammunition, such as Obus G technology, some of these developments might have carried over to the OCC 90-62 HEAT round. The OCC 90-62 is not an Obus G round however. A difference in spin rate and explosive filler type might also have contributed to this disparity or the overall interior design.
Another detail that could be taken into account is the manner of testing. The NR478 is rated at 300 mm when it is tested as a static round (not fired from a gun but discharged point blank at a fixed position). The number of the OCC 90-62 might have come from static testing as well, which would mean that the actual performance might be a bit less. In Jane’s Armour and Artillery 1985-1986, the NR478 is rated as 300 mm at 1,000 meters, while in Engesa’s marketing material and in some table for the Cockerill rounds it is listed as 250 mm. What the correct penetration is, will likely remain a mystery until someone manages to find test reports on both rounds to see where these numbers exactly come from.
90 mm D921
Round
Capability
Effective range
Velocity
HEAT (High Explosive Anti-Tank)
320 mm (12.6 inch) flat at any range.
1,500 meters (1,640 yards)
750 m/s
HE (High Explosive)
Lethal radius of 15 meters (16 yards)
1,500 meters (1,640 yards)
650 m/s
White Phosphorus – Smoke
50 meter wide smoke screen for 20 to 30 seconds
1,500 meters (1,640 yards)
750 m/s
HEAT-TP (High Explosive Anti-Tank – Training Projectile)
Inert (no explosive filling)
1,500 meters (1,640 yards)
750 m/s
The firing table and the ‘’crosshair’’ of the direct-fire telescope for the EC-90 gun went up to 3,000 m for the HEAT round, 2,380 m for the HE and smoke round, and 1,020 m for the coaxial machine gun. The main armament was fired with a pedal on the turret basket floor and could be cut off through the main electrical system box. This box controlled things such as the ability to fire the main and coaxial armament, configure the ventilation system, and internal lights. In some EE-9s, the firing table was added as a plate on the electrical system box as well. The electrical system box was mounted to the right of the gunner. Additional control boxes would be added for equipment such as laser rangefinders and day/night sights if needed.
Although the EC-90 is able to fire a wide variety of ammunition, according to inside sources, the Brazilian Army only uses HEAT, HEAT training projectiles, and HE rounds for the Cascavels. This might change during wartime however. Imbel is responsible for the manufacture of these rounds in Brazil after Engesa’s ammunition manufacturing subsidiary Engequímica went bankrupt along with Engesa in 1993.
90 mm EC-90
Round
Capability
Effective range
Velocity
HEAT – NR 478A1 (High Explosive Anti-Tank)
250 mm-300 mm (9.8-11.8 inch) flat at any range.
2,000 meters (2,185 yards)
890m/s
HESH – NR 503A2 (High Explosive Squash Head)
Meant for bunkers, walls and light vehicles.
2,000 meters (2,185 yards)
800 m/s
HE – NR 501A1 (High Explosive)
Lethal radius of 15 meters (16 yards)
1,600 meters (1,750 yards)
700 m/s
White Phosphorus – Smoke – NR 502A2
50 meter wide smoke screen for 20 to 30 seconds
1,600 meters (1,750 yards)
695 m/s
HEAT-TP – NR 479A2 (High Explosive Anti-Tank – Training Projectile)
Inert (no explosive filling)
2,000 meters (2,185 yards)
750 m/s
The ET-90 I turret used a 7.62 mm N model F-1 machine gun as its coaxial armament. In theory, it could fire 700 rounds per minute, while the practical rate of fire was about 250 to 300 rounds per minute. Its maximum range was 1,200 m and it weighed 10.5 kg. The coaxial machine gun was installed on the commander’s side as the commander acted as the loader, but was fired by the gunner through a button on the main gun’s elevation handle. It could be manually fired by the commander if needed.
The EE-9 carried 2,000 rounds of 7.62 ammunition, divided between 10 cases, and a total of 44 rounds for the main gun, of which 20 were stored in the hull and 24 in the turret. The hull ammunition storage was offered as an optional feature and consisted of boxes installed between the front wheel and the turret ring on both sides. The Brazilian EE-9s seem to operate with the hull stowage racks.
The Brazilian EE-9s are said to operate with night sights in the manuals, but inside sources dispute this claim and state that the EE-9 only uses day sights. How far this is true remains to be seen and it might only be valid during peacetime operations, although the vehicles do not use the SS-122 day/night sights which were sold by Engesa. What is true, is that almost none of the Brazilian EE-9s operate with a laser rangefinder, with only one or two vehicles mounting it, which are either EE-9 M6s or M7s. In addition, the traverse and elevation systems of the Brazilian EE-9s are all manual and not electric, even though electric drives were optional choices. All in all, the Brazilian EE-9s are quite barebones when it comes to fire control systems.
Other Systems
The power of the EE-9 was divided in a 12 V and a 24 V circuit, of which the 24 V circuit was mainly meant for the turret and the 12 V circuit for the general operation of the hull. It used 4 batteries of 12 V and 95 Ah, which were located in the engine bay. In addition, it used a K1 Alternator of 12/14 V and 55 A and a 12V 4 hp starting engine.
The exact radios used in the EE-9s are unknown. The VHF/FM and/or HF/SSB and intercom systems were offered as optional equipment by Engesa. The Brazilian Army used equipment which received their EB11 radio systems, which were widely used in the Brazilian Army. Among potential installations were the EB11 ERC-201 according to a contact in the Brazilian military, or the EB11 ERC-204 which was mounted in an Urutu. A Brazilian Army contact claims that the current Brazilian Cascavels do not use radio equipment or intercoms as the old EB11 radios have been phased out but not replaced by the Brazilian Army. To what extent this is true is unverified, but various videos showing the interior of the EE-9 do not show radios or the usage of intercom equipment.
Supposedly, the lack of radios and intercoms were a result of the EE-9 programs being in limbo. It was uncertain if they were going to be modernized and it was unclear how quickly they were going to be replaced. The lack of a radio has been somewhat solved by using Falcon walkie-talkies with a range of about 10 km, and it should be completely resolved with the modernization program.
Additional features such as a heater and air conditioning system were offered for the EE-9 as well. Interestingly, these two options seem to have been dropped in later variants or at least no longer mentioned in brochures. It might be that there was simply no demand for the systems or it might have had some practical issues. In any case, it is unknown if any Cascavel was equipped with either a heater or air conditioner by Engesa.
The EE-9 did have a ventilation system in the turret and hull to ventilate the fumes from firing the main cannon. Air was sucked from the air intake on the rear turret top and blown out in front of both the commander and gunner on the turret top. The toxic fumes were sucked in through a duct on the rear side of the turret, with an exhaust mounted in the middle of the turret bustle. The hull had two exhaust fans located at the frustums on both hull sides. It is possible that this was the air conditioning system and that it was nothing more than a basic ventilation system.
Organization
Cascavels can be found in a number of brigades (army > division > brigade > regiment > squadron > platoon) within the Brazilian Army, which are in turn subdivided into either regiments or squadrons depending on the type of brigade. The vehicles are used in 7 different types of brigades and 15 brigades in total. The EE-9s are operated in Mechanized Cavalry Squadrons and Mechanized Cavalry Regiments (Esquadrão de Cavalaria Mecanizado and Regimento de Cavalaria Mecanizado respectively) within these brigades. There is one exception, as the 14th Mechanized Cavalry regiment is bound under a division, not a brigade.
List of Brigades, Regiments and Squadrons using the EE-9 in the Brazilian Army (2020)
Division/Brigade type
Division/Brigade
Regiments or Squadrons
Army division
5a Divisão de Exército
14° Regimento de Cavalaria Mecanizado
Jungle infantry brigade
1a Brigada Infantaria de Selva
12° Esquadrão de Cavalaria Mecanizado
Mechanized infantry brigade
15a Brigada Infantaria Mecanizada
16° Esquadrão de Cavalaria Mecanizado
Light infantry brigade
4a Brigada Infantaria Leve (Montanha, Mountaineers)
4° Esquadrão de Cavalaria Mecanizado
11a Brigada Infantaria Leve
13° Regimento de Cavalaria Mecanizado
Motorized infantry brigade
3a Brigada Infantaria Motorizada
3° Esquadrão de Cavalaria Mecanizado
7a Brigada Infantaria Motorizada
16° Regimento de Cavalaria Mecanizado
8a Brigada Infantaria Motorizada
8° Esquadrão de Cavalaria Mecanizado
9a Brigada Infantaria Motorizada
15° Regimento de Cavalaria Mecanizado
10a Brigada Infantaria Motorizada
10° Esquadrão de Cavalaria Mecanizado
Armored infantry brigade
6a Brigada Infantaria Blindada
6° Esquadrão de Cavalaria Mecanizado
Armored cavalry brigade
5a Brigada Cavalaria Blindada
5° Esquadrão de Cavalaria Mecanizado
Mechanized cavalry brigade
1a Brigada Cavalaria Mecanizada
1° Regimento de Cavalaria Mecanizado
2° Regimento de Cavalaria Mecanizado
19° Regimento de Cavalaria Mecanizado
2a Brigada Cavalaria Mecanizada
5° Regimento de Cavalaria Mecanizado
8° Regimento de Cavalaria Mecanizado
3a Brigada Cavalaria Mecanizada
3° Regimento de Cavalaria Mecanizado
7° Regimento de Cavalaria Mecanizado
12° Regimento de Cavalaria Mecanizado
4a Brigada Cavalaria Mecanizada
10° Regimento de Cavalaria Mecanizado
11° Regimento de Cavalaria Mecanizado
17° Regimento de Cavalaria Mecanizado
The structure of the squadrons and regiments is a little different, with the regiments operating a command and support squadron alongside three mechanized platoons in which the Cascavels are operated. The squadrons very roughly forgo the command and support squadron and only use the command and subcommand group and a mortar platoon alongside the three mechanized platoons.
Each mechanized platoon operates a command group, 2 exploration/pathfinder groups, a wheeled armored reconnaissance vehicle section, a combat group, and a support part. The wheeled armored reconnaissance vehicle section operates 2 EE-9 Cascavels. This means that every cavalry regiment and squadron of the Brazilian Army actively operates 6 EE-9s in total.
The Brazilian Army has 23 cavalry regiments and squadrons, which means that Brazil theoretically operates 138 EE-9s. One of the regiments owns 19 Cascavels, which is a little over three times the number they actually operate. If this is taken as a rule of thumb, it would mean that Brazil needs about 414 EE-9s of which a third are in active service and two thirds are in reserve/stocks. This number is reasonable considering the Brazilian Army bought 409 EE-9s of all types from Engesa.
Brazilian Service
Despite operating a total of 157 EE-9 M2s and a total of 409 EE-9s (excluding 6 EE-9 M4s from the Corpo de Fuzileiros Navais; the Brazilian Marine Corps), Brazil never really did anything with the vehicles, while the more modern M7s would be used in the 1996 UN peacekeeping mission in Angola and to suppress the strike at the CSN steel factory in 1988 as passive onlookers.
The actual service number of EE-9s is somewhat in question as well. The current numbers are based on the initial delivery figures by Engesa and do not include any written off vehicles over the years. Some vehicles have been used as part donors and some might simply not be in operation anymore due to old age and bad maintenance. Although the number of actual usable Cascavels is unknown, it is almost certainly less than 409 which has been the active service number since 1988, with the first EE-9s entering service in 1975.
Modernization and Replacement
The first modernization program was proposed to the Brazilian Army by QT Engenharia e Equipamentos Ltda in 1995, 2 years after Engesa’s Bankruptcy. An EE-9 M2 and an EE-11 M2 were modernized by the company with the goal of modernizing as many vehicles in Brazil’s fleet as possible. QT Engenharia won the bid to modernize the two previously mentioned vehicles which were remnants from Engesa’s old stocks when they went bankrupt. The Cascavel received a new fire control system which used night vision and a laser rangefinder, with night vision blocks for the commander, driver and gunner. An automatic transmission was installed, considering the EE-9 M2 did not have access to one, and the drum brakes were replaced with disc brakes. A more powerful 280 hp engine was also considered. The project would have converted every Brazilian EE-9 to an improved version of the most advanced EE-9 Engesa offered until its bankruptcy, offering a more powerful engine than any EE-9 had at the time.The project was canceled in the late 1990s due to high costs.
It is important to note that not a single EE-9 in Brazilian service (April 2022, Cascavel modernisation not yet in service) uses any form of night vision equipment. Although night vision periscopes are mentioned in the manuals, official Army documents and inside contacts dispute this claim and specifically state that not a single EE-9 has these periscopes in the Brazilian Army. In addition, only a handful of EE-9s in the Brazilian Army use a laser rangefinder.
In 1997, the AGSP (Arsenal de Guerra de São Paulo, São Paulo War Arsenal) effectively inherited the role of the PqRMM/2, the maintenance park which had created the prototypes of the Cascavels and had paved the way for a national defense industry. The AGSP was tasked with finding ways to extend the service life of the EE-9 and the EE-11 until they would be replaced by the Guarani and an 8×8 Fire Support Vehicle. The AGSP was not only in charge of modernisation, but also became the most important maintenance location for the EE-9 and the EE-11. This was important as Engesa’s collapse meant that maintenance had ground to a halt for Brazil and all Engesa’s customers. The AGSP collected the modernized vehicles by QT Engenharia after the project was canceled, where they supposedly reside to this day. The AGSP also carried out a modernisation project of their own.
In 1998, the AGSP mounted a full-scale mock up of a low altitude air defense system armed with 2 Piranha missiles on both an EE-9 M2 hull and a more modern EE-11 hull. This system was known as Simbada, an acronym for Sistema de Defesa Aérea a Baixa Altura which translates to Low Altitude Air Defense System. The concept was not further developed on either the EE-9 or EE-11.
The AGSP initiated its maintenance line in 2001 and had refurbished and standardized more than 200 EE-9s and EE-11s by 2011. The goal set was to fully refurbish about 500 EE-9s and EE-11s out of the combined total of 639 EE-9s and EE-11s. How many have been refurbished fully is unknown. What is known is that the refurbishment process began with the newest vehicles and would work its way through the older vehicles.
It is however very likely that the EE-9 M2 will be phased out and retired from service in the coming decade. Brazil is planning to replace its Cascavel fleet with a yet unknown (April 2022) 8×8 Fire Support vehicle like the B2 Centauro or the LAV-700. To bridge the transition process from EE-9 to the new FSV vehicles, Brazil has initiated a modernisation program for its Cascavels. The modernized EE-9 will receive a new drive train, new fire control systems, and a command and control computer system among other upgrades.
The prototype of this modernisation was built by Equitron, which designated the vehicle EQ-12. The Army designated the modernized vehicle as EE-9U, and the AGSP as MX-8. An EE-9 M2 was again the test subject for this modernisation program and it was delivered to Equitron in the middle of 2014.
Equitron initiated its modernisation and would also acquire the contract for a further modernisation of the turret, which was to be fully automated (the initial modernisation had not yet proposed extensive turret modernisations). By 2016, the modernized EE-9 M2 was completed and Equitron is currently trying to secure the contract for the modernization of 98 to 201 EE-9s.
These limited numbers could suggest that the EE-9 M2s will be phased out in the coming decade or two as it is the oldest of all the EE-9s in service. It is unlikely that the EE-9 M2 will be modernized due to its age and will either continue operations in its current state until it is replaced by the 8×8 FSV or the vehicles will be put in storage. Regardless, the future of the EE-9 M2 is uncertain.
Another interesting modernisation of the EE-9 appeared in 2019, which was built on the exact same hull as the EE-9U prototype, evidenced by the exact same registration. An EE-9 armed with a TORC-30 turret was presented by ARES Aeroespacial and Equitron at the LAAD Defence and Security exposition. The prototype has not yielded any success so far and the original modernized turret of the EE-9U was again mounted on the hull.
Maintenance
One of the biggest challenges Brazil and many other countries using Engesa vehicles had to face after Engesa’s bankruptcy in 1993, was maintenance. Engesa would have been hired to do extensive maintenance work or refurbishment, but users had to figure out what to do with the vehicles they had. Colombia attempted to copy the EE-11 Urutu by creating the Zipa, but this was unsuccessful. The AGSP took on the role of maintaining the Brazilian fleet in Brazil.
Luckily, a number of companies arose after Engesa’s bankruptcy to keep maintaining the vehicles. Companies such as Universal and Columbus International were founded or started supplying spare parts for Engesa vehicles shortly after Engesa’s bankruptcy. Universal was already around in 1967, providing the Brazilian Army with parts from that point onwards. In 1992, it started supplying components for Engesa vehicles with Engesa’s impending bankruptcy and in between 1996 and 2000 the company managed to buy up a large number of vehicles, machines, equipment, tools, and about 30,000 components from Engesa’s bankruptcy auctions. From this point onwards, Universal would start maintaining vehicles for Brazil and other countries and even sold 8 Urutus to the Brazilian Army.
Columbus was founded in 1993 by ex-Engesa employees with the goal of maintaining, modernizing, and developing new projects for Brazil and the countries that operated Engesa equipment. Columbus would go on to develop the Marruá jeeps of which the designs were sold to Agrale. The Marrua is effectively a redesigned EE-12 jeep and is slowly replacing the Brazilian Army’s old jeeps and has seen export success as well. Columbus and Universal both ensured that the Cascavel and Urutu would still have many service years ahead of them and would support the AGSP in maintaining them.
When an EE-9 or EE-11 arrives at the AGSP for maintenance it is fully disassembled. Each component will then be sent for individual checks and maintenance. The hull will be stripped of paint with a sandblaster and subsequently repainted. The entire vehicle will then be reassembled and tested.
Among specific services are the complete overhaul of engines and replacement of the 50 A alternator with 75 A alternatives as the 50 A is not locally produced anymore. The AGSP also does overhauls for the entire drivetrain with the incorporation of some minor improvements over the original design. The turret and armament will be overhauled as well with a potential replacement for the gun if needed, as there are Cascavels still using the original gun breeches from Engesa.
Tyre Shortage
Brazil suffered a tyre shortage for the EE-9 and EE-11 after Engesa went bankrupt from 1993 until at least 1995. The tyres were not mass-produced by the Brazilian industry as the specific manufacturing process of the run-flat tyres was no longer used. The Brazilian Army opted to import Continental tyres from the Czech Republic but these were rejected during testing. The solution was found in using locally produced truck tyres instead, which the Colombians had been doing for some time.
This shortage lasted until at least 1995 and potentially until 1997 or longer. Fourteen EE-11s and 2 EE-9 M7s were sent to the UNAVEM III (United Nations Angola Verification Mission III) UN peacekeeping mission in Angola in 1995. In order to provide the spare tyres needed, the tyres of a number of EE-9s or EE-11s of the Brazilian Army were cannibalized. This lack in tyres is likely a contributing factor for the Brazilian Army to actively start looking for a solution to the matter, even though this should have been done the moment Engesa went bankrupt.
The harrowing need of the Brazilian Army having to cannibalize tyres for a 2 year mission with just 16 vehicles is indicative of Brazil’s incapability to fight any sort of war with the 609 EE-9s and EE-11s during this time period as no spare tyres would have been available in the initial stages of a potential war. The lack of initiative from the Brazilian Army to solve the issue quickly might have come from the economic difficulties of Brazil during the 1990s or due to bureaucratic issues.
Foreign service
The foreign service of the EE-9 M2 and M3 will be divided in two sections: first with direct exports to Bolivia, Chile, Libya, and a second with international actors that acquired the EE-9 through exports, donations, and captured equipment. Libya has, for example, donated or lost a significant number of the 400 EE-9s they bought from Engesa.
Direct Exports:
Bolivia
Bolivia received 24 EE-9 M2s with the HS-90 turret from Engesa around 1976-1977. They were painted in a yellow and brown camouflage scheme, although the Bolivian EE-9s have been repainted over the years in yellow or in a dark green tone. The EE-9s carry their unit markings usually on the lower side plate between the front wheel and the boomerang suspension. The registration should not be confused with Brazil, Bolivia uses E.B.33-XXXX (with the XXXX seemingly ranging from 0101 to 0124), while the Brazilian Army used EB10-XXX or, more recently, EBXXXXX. Not all Bolivian EE-9s carry their registration however, which seem to have been lost in between repaintings.
Bolivia has used their EE-9s mainly against protests as supposedly passive onlookers. One of these examples was when they were used against the Marcha por la Vida (March for Life) on August 21st 1986.
In an attempt to combat severe economic crisis and hyperinflation, the Bolivian Government enacted Decree 21060 in 1985. The Decree was a shock therapy for the Bolivian economy, adapting tariffs which caused prices to increase drastically, the dismissal of two thirds of the tin and oil company employees from government-managed companies, and the wage freeze of the other third until December 1985. It essentially meant liberalization of the market, removing restrictions on foreign trade which put local production under huge pressure and the end of foreign debt payment for a number of years.
Although the Decree managed to stop the hyperinflation, it also meant that more than 25,000 mine workers and the companies closed down, which in turn affected many other industries in the country. The overall effect of Decree 21060 was devastating for many households in the country. The protestors walked from Oruro to La Paz (the capital of Bolivia) from August 21st to August 29th 1986, until they were stopped and surrounded by the Bolivian Army which used EE-9s as passive onlookers.
In 2003, the EE-9 was used again during the Bolivian gas conflict. The conflict was a culmination of economic policies, coca eradication policies, corruption, and military suppression. The catalyst was a gas pipeline route to the Pacific Ocean which would have had to go through Chile in early 2002. Anti-Chilean sentiments were high, and Bolivians campaigned for the pipeline to go through Peru. In 2002, elected president Gonzalo Sánchez de Lozada expressed his preference for the Chilean option which resulted in heavy protests in the country. EE-9s were used in La Paz as guardians for the Government Palace and National Parliament and for blocking certain streets. The protests resulted in the resignation of President Gonzalo Sánchez de Lozada and around 60 protesters were killed, most of which in El Alto, where martial law was declared.
Chile
The Chileans were perhaps the most interesting original EE-9 M2 buyers of them all. Chile was the only country to buy EE-9s with both the HS-90 turret and the ET-90 I turret and thus using two different 90 mm guns as well (D-921 and the EC-90). They received their first 60 vehicle EE-9 M2 batch with the HS-90 in 1976-1977 and received an additional batch of 23 EE-9 M2s with the ET-90 I in 1978-1979.
The conscript crews of these vehicles had to be rapidly trained as Chile and Argentina were on the brink of war over the Beagle Channel, known as the Beagle Conflict. These tensions rose so much that in 1978 an invasion by Argentina occurred for a few hours, but the impending war was stopped by an intervention from Pope John Paul II, who mediated the situation.
The Chilean EE-9s have received three different camouflage schemes. These include a single tone sand color, a three tone MERDC-style sand, black and dark green, and a three tone sand, dark green and brown. The Chilean EE-9s were retired from service around 1999-2000 and an unclear number of these EE-9s were sold to Israel at an equally unclear date. After modernization, Israel subsequently sold them to Myanmar with likewise vagueness.
Libya
Libya was the largest operator of the EE-9 M2 and EE-9 M3, operating a total of 400 EE-9s, 200 of each model. The Libyan EE-9 M2s used the D-921 90 mm gun, the manual Clark transmission, and the OM352 engine, while the M3’s used an automatic AT-540 transmission, the OM352A engine, and was the first operator of the EC-90 armed ET-90 I turret. Libya was also the first country to use them in combat during the Four Day War of 1977 and the skirmishes preceding it.
The Libyans continued to use them during the four Chadian-Libyan wars between 1978 and 1987 which culminated in the Toyota War of 1987 and a Chadian victory. During this string of conflicts, the Chadians are said to have captured around 60 EE-9 M2 and M3s from the Libyans. One of these EE-9 M2s ended up in the Saumur Tank Museum in France. The vehicle from Saumur was received in 1986, presumably captured by the French which fought on the Chadian side.
Libya would also donate or sell an unknown number of EE-9s to various international actors in Africa as part of a military diplomacy strategy. These include Burkina Faso, Congo, Ghana, Polisario Front (Sahrawi Organization in the Western Sahara), and Togo.
The most recent usage of the EE-9 in Libya was the Arab Spring and the resulting two civil wars in 2011 and from 2014 to 2020. Supposedly, a large number of EE-9s were in storage which are thought to have been looted during the civil wars. A number of EE-9s were operated by various movements in the country, with some turrets appearing to have been remounted on hulls of other models. A number of EE-9s with improvised side skirts have also been seen. An unknown number of EE-9s have also had their 90 mm guns removed, which were then mounted on pick-up trucks. These pick-ups are armed with both the D-921 and the EC-90 guns.
Other Operators:
Burkina Faso
Burkina Faso received an unknown amount of EE-9s from Libya. SIPRI (Stockholm International Peace Research Institute) lists two batches of 12 EE-9 Cascavels each for a total of 24 vehicles. These were supposedly delivered in 1983 and 1984. Very little is known about these vehicles and only a handful of pictures of these vehicles are known to exist. 3 EE-9 M2’s can be seen carrying out maneuvers in a video released by RTB.
Burkina Faso uses a four tone camouflage with sand, green, black and green as its tones. A small flag of Burkina Faso is also painted on the lower hull front, together with a registration. The two EE-9s that appear in the pictures do not have a laser rangefinder. The status of these EE-9s is unknown.
Chad
Chad captured its EE-9s from Libya during the Chadian-Libyan wars from 1978 to 1987. Around 60 EE-9s M2 and M3s are said to have been captured and are, as far as is known, in storage. Some of the captured vehicles do have battle damage and most of them would need refurbishing to be put into service. To showcase Engesa’s business policy, from 1990 up to 1993, when the company faced bankruptcy, the company was in talks with Chad to effectively refurbish the captured EE-9s. In the end, the contract was never signed as Engesa went bankrupt in 1993.
The Chadian EE-9s may have seen combat during the Chadian-Libyan wars in Chadian service, but this is unknown as details of these conflicts remain limited. The Chadian EE-9s seem to have retained the camouflages from the Libyans, using single tone sand or two tone sand and green. It is possible that EE-9s were used during the Chadian civil wars and the Maghreb insurgency campaigns, but no information exists to support this.
Democratic Republic of the Congo
The Democratic Republic of the Congo (DRC) seems to have received at least 3 EE-9s. Their origin is vague as they operate 1 EE-9 M3 which has the Libyan periscope layout, but the EE-9 M2s use 3 periscopes for the driver. It is possible that these were later acquired through perhaps Israel like Myanmar did, but this is speculation. When these were acquired and how many remain is unclear. The vehicles are painted in a dark green tone and their status is unknown.
At least one EE-9 was used during protests of the 2006 general election. This was the first multiparty election in the country in 41 years. A significant number of protests took place before the election with fatal casualties as a result of fighting between the protestors and the Army. It is possible that the EE-9 was either used as a passive onlooker or to crack down on one of these protests. In the end, the election results remain somewhat questionable due to the events leading up and during the election. Joseph Kabila was voted in as president with 58% of the votes in the second election round (45% in the first) and the People’s Party for Reconstruction and Democracy won the parliamentary elections with 111 seats.
It is possible that the EE-9 saw service during the First and Second Congo wars, the Kivu and Ituri conflicts, and other conflicts or unrest inside the country ranging from 1996 to this day, but no sourcing proves this.
France
France obtained a single EE-9 from the Libyans in 1986. If the vehicle was captured by the French or was provided by the Chadians is unclear. The French EE-9 is now located at the Saumur Museum. With the help of Hadrien Barthélemy, a contact with access to the vehicles, the writer has discovered that the first batch of Libyan EE-9s were actually M2s instead of M3s. In addition, the Museum provided documents on the date of the capture of their EE-9’s and interior pictures. The Saumur Museum has been tremendously helpful in uncovering new information on the EE-9 and the writer would like to thank the Museum for their help.
Ghana
Ghana is or was an operator of which virtually nothing is known. All that is known is that they have at least a single EE-9 which seems to come from the Libyan batch. When they obtained them and how many is a mystery. The only known Ghanaian Army EE-9 uses a H-90 turret, which means that the hull is likely to be an M2 hull as well. It is painted with a three tone camouflage consisting of sand, black and a dark green. The EE-9 is seen loaded up in an Ilyushin IL-76 supposedly in 2011. No other pictures have been found. The EE-9 might have seen service during the First Libyan Civil War, the Sierra Leone Civil War, The First and Second Ivorian civil wars, the Mali War, the ECOWAS military Intervention in the Gambia, and the Western Togoland Rebellion, although nothing proves this.
Polisario Front
The Polisario Front is perhaps the most interesting group to receive EE-9s from Libya. This is because the Polisario Front is a liberation movement recognised for representing the Sahrawi people, the indigenous people of the Western Sahara. The Polisario Front was officially formed on May 10th 1973 in an attempt to drive out the Spanish from the Western Sahara.
Spain would cede the Western Sahara over to Mauritania and Morocco after the Madrid Accords, effectively causing the Polisario Front to fight both countries. After a coup d’etat in Mauritania in 1978, a peace treaty between the Polisario Front and Mauritania was signed in 1979 with Mauritania recognizing the Sahrawi Arab Democratic Republic and antagonizing Morocco. Morocco attempted to fully annex the region and a guerilla war rages to this day, with a ceasefire from 1991 to 2020 in between. Libya is thought to have supplied arms to the Polisario Front from around mid-1970 to mid-1980.
Among these weapons are an estimated 19 to 30 EE-9 Cascavels (19 according to Oryx and 30 according to Expedito Carlos Stephani Bastos). According to Oryx, these EE-9s were potentially delivered around the early 1980s. Based on the limited pictures available, at least 5 ex-Libyan EE-9 M2s were in service with the Polisario Front. These vehicles were painted in a single tone sand or in a two tone sand and dark green, with registration numbers on the turret sides. How many EE-9s remain in service is unknown.
Myanmar
The acquisition of the EE-9 to Myanmar, like with other second-hand users, remains clouded with mystery. SIPRI estimates that 12 EE-9s were sold to Myanmar in 2007 and delivered around 2009-2010. The earliest date in Myanmar sourcing seems to be around 2011, which does somewhat seem to support the delivery date. A video of Saymar Ltd (the Israeli company which sold the EE-9 to Myanmar) showing an EE-9 appeared in 2008, with testing videos appearing in 2010 on YouTube which only further seems to support SIPRI’s data. The largest number of Cascavels in a single picture from Saymar and Myanmar total for 11 EE-9s.
A Brazilian source however claims that 70 EE-9’s were bought from Chile in 2002. This might be possible considering Chile retired them, and it could be possible that this is actually the total number Saymar bought from Chile. It would then be the case that Saymar only managed to sell 12 EE-9s to Myanmar. No sale between Chile and Saymar shows up in SIPRI. There are claims that Mynanmar operates well over 100 EE-9s, but this seems unlikely considering Chile only owned 83 in total.
The Myanmarian EE-9s mainly received a refurbishment with some additional improvements. The original OM352A engine was replaced with an OM366LA 190 horsepower diesel engine, and the fire control system was optimized, including sights and electric turret and gun drives. In addition, the driver’s panel and overall electrics were revitalized and the brakes and suspension were refurbished as well. The refurbished and modernized EE-9s mainly present quality of life upgrades over the old models, but do not seem to be better than the later stages of the EE-9 development, like the EE-9 M4.
In addition, it seems that the Myanmarian EE-9s do not have a laser rangefinder unless they installed it internally in some way. The Myanmarian EE-9s appear to mount the Singaporean 12.7 mm STK 50MG machine gun in combination with a simple steel plate to provide cover for the commander. The EE-9s also appear to have received a stowage rack on the turret bustle, which was not standard on the H-90 turret.
The Cascavels from Myanmar were painted in dark green and received registration on the lower front plate and the turret sides, although the turret side registration does not appear on every Cascavel. The Cascavels are most likely, and seem to have been used based on pictures, against the many insurgencies plaguing the country over the course of the last two decades. They might also have been used during the 2021 coup d’etat and the subsequent resurgence of armed resistance by protestors against the new junta.
Togo
The Togolese Army received a number of EE-9s from Libya through exports. SIPIRI lists anywhere between 3 to 36 EE-9 Cascavels to have been delivered by Libya around 1982 to 1983. Based on a Latin America Report from 1985, Togo would have 5 to 6 EE-9s. In a newspaper entry from Togo from 1980, 5 platoons consisting of 3 vehicles each were said to have been created, consisting of the UR-416, the AML-90 and the EE-9. This would mean that Togo would have 5 EE-9’s in active service and either one or none in reserves.
The Togolese EE-9s may have been used during the First Ivorian Civil War, the Guinea-Bissau Civil War, the Mali War, and the ECOWAS military intervention in the Gambia. No proof exists of the EE-9s participation in any of these conflicts or even further proof of EE-9s in Togolese service exists.
Variants
The EE-9 M2 and M3 have had a significant number of variants built from them. A reason for this was because these were the oldest vehicles. Brazil essentially only sacrificed their EE-9 M2s for any prototype considering they were old. This has meant that the variants of the EE-9 M2 range from the very early days up to the present day with the latest EE-9 modernisation project being a conversion from an old M2 Cascavel.
There are a few exceptions in this list. The variants list will not comprise EE-9s armed with the H-90, ET-90 I, and ET-90 II turrets as these are already covered in the article. Any foreign variants will not be included if the upgrade was not carried out by Engesa as these variants are already covered in the sections from their respective countries.
EE-9 M2 SIMDABA
The EE-9 M2 SIMDABA was a prototype developed in 1998. SIMDABA stands for Sistema de Mísseis de Defesa Aérea de Baixa Altitude (Low Altitude Air Defence Missile System). The EE-9s turret was replaced with a system carrying two locally developed and produced Piranha MAA-1 anti-aircraft missiles. The vehicles would use the FILA fire control vehicle from Avibras as its operating system. The idea came from the AGSP and the PqRMnt/1 (Parque Regional de Manutenção da 1ª Região Militar, Regional Maintenance Park of the 1st Military Region) built the mock-up prototype.
The SIMDABA system was designed to provide quick and mobile air defense for important targets such as military columns, ports, airports, supply lines, and so on. As a result, the SIMDABA system was mounted on vehicles such as the EE-9 and the EE-11, but also on ships, trucks, and with towed anti-aircraft platforms. In the end, the project and the SIMDABA project more broadly seems to have gone nowhere.
EE-9 M2 QT Engenharia
The first modernisation program was proposed to the Brazilian Army by QT Engenharia e Equipamentos Ltda in 1995, 2 years after Engesa’s Bankruptcy. An EE-9 M2 and an EE-11 M2 were modernized by the company with the goal of modernizing as many vehicles in Brazil’s fleet as possible. QT Engenharia won the bid to modernize the two previously mentioned vehicles which were remnants from Engesa’s old stocks when they went bankrupt. The Cascavel received a new fire control system which used night vision and a laser rangefinder, with night vision blocks for the commander, driver and gunner. An automatic transmission was installed, considering the EE-9 M2 did not have access to one, and the drum brakes were replaced with disc brakes. A more powerful 280 hp engine was also considered. The project would have converted every Brazilian EE-9 to an improved version of the most advanced EE-9 Engesa offered until its bankruptcy, offering a more powerful engine than any EE-9 had at the time.The project was canceled in the late 1990s due to high costs.
EE-9 EQ-12
The EE-9U is the Army designation for the modernisation program of the Cascavel, which was initiated in the early 2010s. The company Equitron, which managed to acquire a number of the old companies supporting Engesa in producing components such as brakes, would help in the maintenance of a number of EE-9s by providing brand new components. With the success of this project, Equiton was invited to participate in the bidding process for the overhaul of an EE-9 M2 in 2013. Equitron secured the contract and the EE-9 M2 was delivered to them in mid-2014.
In 2015, the Brazilian Army opened another bidding for a modernized EE-9 which would again be secured by Equitron. The Equitron engineers initiated the design of a modernisation package which could be mounted on every Cascavel model of the Brazilian Army. The prototype was designated EQ-12 by Equitron, MX-8 by the AGSP, and EE-9U by the Army.
The engine was replaced with an OM906LA in-line diesel engine. The engine provided 264 hp at 2,200 rpm and 1,100 Nm at 1,600 rpm. The manual Clark transmission was replaced with a ZF 6HP 504C automatic transmission with 5 forward and one reverse gears. The ZF transmission was paired with a MB VG 550 Mercedes-Benz transfer case which offers a high and low gear option.
The main upgrade was to the fire control system. The Cascavel was outfitted with a optronics block on top of the gun, which offers thermals, a laser rangefinder, and laser illumination. In addition, 4 day/night cameras are positioned on each side of the vehicle for 360° view. The turret is outfitted with electric turret drives and the gun and turret are controlled with a joystick. All three crew members have access to a computer screen for vision and control of the systems, such as the gun. The integration of ATGMs on the turret sides was also considered.
The prototype was first tested at Marambaia Proving Grounds in the first half of 2016, with firing tests in October of the same year. The EE-9 modernization program then ended up being shelved for a while and was revived in 2021. Brazil was going to buy 8×8 Fire Support Vehicles, but it would need the Cascavel to remain in service until the deliveries were completed which was expected around 2040. Considering the EE-9 was almost 50 years old at this point, it was clear that it also needed to be modernized. A bidding for the contract was opened in February 2022, but was won by Akaer’s proposal.
Equitron’s proposal seems to have simply required too many structural changes to the vehicle which made it too expensive. Akaer’s proposal did not introduce these significant changes but kept it at the needed requirements to match the contract. As such, Akaer’s proposal is not as good, but is more affordable. In a way, it makes sense, as modernizing a 50 year old armored car as a stopgap should not cost a fortune.
EE-9 with TORC-30
The Brazilian companies Ares and Equitron presented a prototype for a TORC-30 armed EE-9 at the 2019 LAAD exposition. The turret was mounted on top of the original EE-9U prototype from Equitron as it shares the exact same registration. The TORC-30 was designed by Ares (a subsidiary from the Israeli company Elbit) and CTEx (Centro Tecnológico do Exército, Army Technology Center).
As the name suggests, the turret is armed with a stabilized 30 mm Rheinmetall MK30-2/ABM autocannon and can engage both ground and air targets. It has two magazines with 150 and 50 rounds each and a rate of fire of 600 rounds per minute. It can receive armor up to Stanag 4569 level 4 and anti-RPG capabilities. The turret has a hunter/killer and laser warning system combined with thermals and a high definition day camera.
The exact reason why the EE-9 with the TORC-30 was built remains somewhat uncertain. It was likely meant as a testbed for the turret and as a marketing opportunity. The EE-9 with TORC-30 could provide some additional anti-aircraft defenses, but it does not have the protection levels to serve as an infantry fighting vehicle, nor does the amount of ammunition seem to help in this regard. The Brazilian Army essentially concluded this already as far back in the 1970s, where it had recognised the inadequacy of an autocannon on the EE-9 platform as a ground combat vehicle, so the only opportunity would be anti-aircraft in the form of drone defense, for example.
Conclusion
The 90 mm armed EE-9 M2 was Engesa’s successful debut to the arms exporting industry. Although having a bit of a hitch because the Brazilian Army spent half a decade deciding what to arm it with, Portugal however, saw potential. Portugal liked the EE-9 platform, with its bimetal armor and Boomerang suspension offering excellent mobility and good protection for its weight, but disliked the 37 mm gun and wanted the 90 mm instead. This proved to be excellent advice, as Engesa would soon after sell 400 90 mm armed EE-9s to Libya in two batches and 107 more to Bolivia and Chile.
These sales and the supposed success of the EE-9 in service with Libya laid the foundations for the future success to build upon. The EE-9 M2 and M3 were still somewhat barebones with the manual transmission for the M2 and the headlights on top of the hull, but with the new funds, Engesa would redesign the turret and the headlights, in addition to offering improved drive components.
The M2 proved that a vehicle could be simple, cheap, effective, reliable, and use essentially heavy automotive/truck components to succeed. The early EE-9s not only provided the money so that Engesa could undertake increasingly ambitious projects, but also showed that a country making simple vehicles could turn into the 6th largest arms exporter with a market fixated on the so-called Third World. The 90 mm armed EE-9 M2 is essentially the vehicle that put the Brazilian arms industry on the map.
Specifications (EE-9 M2 37 mm)
Dimensions (L-W-H)
6.22 m (with gun) x 2.59 m x 2.3 m (20.4 feet x 8.5 feet x 7.5 feet)
Total weight
11 tonnes (12.1 US tons)
Crew
3 (Driver, commander, gunner)
Propulsion
Mercedes OM352 or OM352A (125 and 172 hp)
Speed (road)
95 km/h (59 mph)
Operational range
750 km (466 miles)
Armament
90 mm DEFA D-921 (HS-90)
90 mm EC-90 (ET-90 I)
7.62 mm N model F-1 (Coaxial)
Armor
Hull Bimetal
Front 16 mm (0.63 inch)
Side 8 mm (0.32 inch)
Rear 8 mm (0.32 inch)
Top 6.5 mm (0.26 inch)
Floor 6.5 mm (0.26 inch) HS-90 Turret
Front 14-15 mm (0.6 inch)
Rear 7 to 8 mm (0.3 inch) ET-90 I turret
All-round 16 mm (0.63 inch)
Top 8 mm (0.32 inch)
Produced
464 M2s and 200 M3s
Special thanks to Expedito Carlos Stephani Bastos, the leading expert of Brazilian armored vehicles https://ecsbdefesa.com.br/, Jose Antonio Valls, an Ex-Engesa employee and expert in Engesa vehicles, Paulo Bastos, another leading expert of Brazilian Armored vehicles and the author of the book on Brazilian Stuarts and the website https://tecnodefesa.com.br, Adriano Santiago Garcia, a Captain in the Brazilian Army and ex-company commander on the Leopard 1 and ex-lecturer on the Brazilian Armored School, and Guilherme Travassus Silva, a Brazilian with whom I was able to endlessly discuss Brazilian Vehicles and who was always willing to listen to my near endless ability to talk about them.
Sources
Engesa EE-9 Cascavel 40 anos de combates 1977-2017 – Expedito Carlos Stephani Bastos
Ford M-8 Greyhound Exército Brasileiro – Surge o conceito de blindado 6×6 – Expedito Carlos Stephani Bastos
Blindados no Brasil – Expedito Carlos Stephani Bastos
Brazilian Stuart – M3, M3A1, X1, X1A2 and their Derivatives – Hélio Higuchi, Paulo Roberto
Bastos Jr., Reginaldo Bacchi
Engesa manuals
Equitron manual
Engesa brochures provided by Ed Francis http://www.lexicarbrasil.com.br/
Dual Harness skin stops armor-piercing projectiles Article of Richard M. Ogorkiewicz
Sipri Arms Transfer Database
Stuart: A history of the American Light Tank, Volume 1 – R.P. Hunnicutt
Armored Car: A history of American Wheeled Combat Vehicles – R.P. Hunnicutt
Juan Miguel Fuente Alba Poblete, Familia Acorazada del Ejército de Chile. Historia de los Vehículos Blindados del Ejército (1936-2009) (Santiago de Chile: Ejército de Chile, 2009)
Personal correspondence with Ex-Engesa Employees
Personal correspondence with Expedito Carlos Stephani Bastos
Personal correspondence with Paulo Roberto Bastos Jr.
Personal correspondence with Adriano Santiago Garcia
Federative Republic of Brazil (Late 1970s)
Armored Personnel Carrier – 1 Prototype Built
When Engesa started manufacturing the Cascavel and Urutu in the early 1970s, the idea of an armored personnel carrier armed with a 60 mm gun/mortar armed turret was conceived. Such a vehicle was already mentioned in early catalogs and a single prototype would be realized somewhere in the late 1970s. The exact goal or customer for the 60 mm Gun/Mortar Urutu is unknown, but it is likely that the success of the 60 mm gun/mortar armed AML-60 in Africa may have had some influence.
The Urutu was meant to transport troops and provide close fire support for infantry against resistance points and in urban combat. The Gun/Mortar carrier was not successful as no vehicles of the variant seem to have been sold. In the end, like a number of other variants of the Urutu, it seems to have mainly been a project for the sake of providing extra options and hoping to enter an oversaturated market of 60 mm gun-mortar carriers in Africa.
The Urutu
The Urutu was Engesa’s troop transport, designed by Engesa and the Brazilian Navy. The vehicle was designed from the ground up to be amphibious, and was approved in 1972 after successful testing in various conditions. it was modified with multiple snorkels, propellers, and a wave breaker for operation on open sea.
Serial production began in 1975, using the same suspension, engines, and transmission as the Cascavel. It managed to achieve large sales to Iraq, Libya, and most of South America, but the Urutu would never reach the same success as the Cascavel. Both the Cascavel and Urutu were upgraded throughout their production runs with different engines, transmissions, and brakes, as well as different hull designs. The Urutu was operated by a driver and commander, and could carry 10+2 fully equipped infantrymen (with the +2 sitting at the side doors of the vehicle).
In addition, it could be equipped with a multitude of different turrets (including Anti-Aircraft). The Gun/Mortar Urutu was made by mounting a 60 mm mortar armed turret on it. Apart from the turrets, the Urutu could also receive various optional components, like an automatic fire suppression system, amphibious equipment and Nuclear Biological Chemical (NBC) protection, all at the client’s discretion.
The Gun/Mortar Concept
Why exactly Engesa decided to offer a gun/mortar carrier is unknown, but a reasonable deduction can be made from the French Panhard AML and the South African Eland armored cars. According to SIPRI, about 3,100 60 mm gun/mortar and 90 mm D921 armed AMLs and Elands were sold to many African and South American countries, of which at least about 580 were armed with various versions of 60 mm gun/mortars.
The gun/mortar concept was meant to provide close infantry support, the protection of logistical routes and troop deployment zones, the neutralization of small resistance points, like machine guns or strengthened positions, terrain clearing, and urban combat. In short, these vehicles were meant to provide all sorts of infantry support, be it direct or indirect fire. Especially the indirect fire capability would give the gun/mortar a wheel-up over the 90 mm armed AMLs, which would only be able to fire at direct targets and may not have been as cost-efficient per shot.
The Prototype, Further Marketing
Considering the amount of gun/mortars sold to African nations and the relative ease of incorporating such a platform on an existing vehicle. It is perhaps not surprising that Engesa offered it as an option for the Urutu. The Urutu was an APC which transported troops to the battlefield. Since the Urutu was now at the front anyway, it might as well have been able to support the infantry it just dropped off with the mortar. In essence, Engesa did not have to do much more than either buy a 60 mm armed turret or just buy the mortar and design a simple turret around it. Apart from that, they had to offer ammunition stowage racks inside the vehicle.
The first mention of a gun/mortar variant of the EE-11 is in a brochure dating after 1976. Here, the possibility of arming an Urutu with a turret mounted 60 mm mortar is mentioned. Interestingly, this exact brochure also already shows the prototype having been built on the cover. The prototype was converted from an M2 hull, which would suggest that the prototype was built somewhere in between 1976 and 1980 (from that point on, the EE-11 M3 hull was introduced).
From then on, the 60 mm Urutu would continue to be marketed for more recent hull models. Instead of the manual transmission which was used on the M2 hulls, the automatic MT-643 transmission was offered. The marketing would be to no avail however, as not a single country is known to have acquired the 60 mm Gun/Mortar Urutu.
The Gun/Mortar EE-11 Urutu in Detail
Overall dimensions were the same as the normal Urutu, with the exception of the height and weight, due to the turret. It was 6.15 m (20.2 feet) long, 2.59 m (8.5 feet) wide, and about 2.7 m (8.9 feet) tall, which was about 0.5 m (1.6 feet) taller than the original Urutu. It weighed around 13 tonnes (14.3 US tons), about 1 tonne (1.1 US tons) more than the Urutu. This could change even further depending on the engine used. It was operated by a crew of two plus eight (commander and driver and 8 passengers).
Hull
The Gun/Mortar Urutu’s hull was the same as the regular Urutu’s with no major difference whatsoever except the redesigned troop compartment for ammunition stowage. The choice of engine, transmissions and modifications, such as automatic fire extinguishers, were up to the client’s discretion.
The Urutu was armored with 12 mm (0.5 inch) thick armor at the front and 6 mm (0.25 inch) on the sides and rear. It used Bimetal steel which offered an improved protection to weight ratio compared to standard steel. The Bimetal armor offered around 1.8 times the effective thickness of an equivalent homogeneous plate against 7.62 mm ammunition, meaning the Urutu had an effective homogeneous thickness of 21.6 mm (0.85 inch) at the front and 10.8 mm (0.43 inch) at the sides and rear against 7.62 mm fire.
The hull was welded and angled at the front, with a minor angle at the sides and rear. The rear angle varied depending on the model, with earlier models having a triangular shape, while the later models had a flat rear. The rear door was operated by the driver or manually by the passengers. All Urutus had two side doors.
The driver was positioned in the front left of the vehicle, next to the engine. The engine was located in a separate compartment. The exact placement of the crew members is unknown, but based on other Urutus with similar troop transporting capabilities, it is likely that 6 soldiers would be located in the troop compartment and a soldier per side door, totalling 8 troops. The commander/gunner/loader was positioned in the gun/mortar turret.
The placement of the frontal headlights also varied with the hull version. Early versions had external headlights mounted on the upper front plate, while later versions had hull integrated headlights. Attachment hooks for towing cables were present in the front, sirens could be attached to the front sides of the hull. A stowage point for a towing cable was present in the left side of the vehicle, while, on some versions, the right side was occupied by the exhaust pipe. The Urutu was fully amphibious, although amphibious equipment such as propellers, rudders and snorkels were optional. A swimming vane operated by the driver was fixed to the top of the frontal hull plate.
The driver had a steering wheel and, depending on the version, would have a brake and gas pedal to the right side of the steering wheel. The gear shift for the automatic transmission was located on his right side and the instrument panel was located on his left side. The driver had 3 periscopes at his disposal, which could be upgraded to day/night periscopes.
Mobility
The Gun/Mortar Urutu was offered with 2 main engines in combination with various transmissions, although more options were possible depending on the client’s wishes.
Engine
Fuel
Horsepower
Torque
Mercedes OM352A (turbocharged)
Diesel
190 at 2,800 rpm
431 Nm at 1,800 rpm (318 ft-lb)
Detroit DDA 6V53N
Diesel
210 at 2,800 rpm
598 Nm at 1,800 rpm (441 ft/lb)
The engines were offered with a range of transmissions depending on the timeframe. From 1976 to 1980, it would have used a manual Clark transmission with 5 forward and 1 reverse gears, and an Allison MT-643 automatic transmission with 4 forward and 1 in reverse gears afterwards. Only the MT-643 could be paired with the Detroit engine. In addition, the Urutu used an Engesa 2 speed transfer case, which allowed the vehicle to be used in reduced and high gear. By putting the Gun/Mortar Urutu in reduced gear, it sacrificed horsepower for torque, making it more effective at climbing slopes. The vehicle also offered a power take off function for the propellers through the transfer case.
The Urutu had a maximum road speed of around 95 km/h and a maximum water speed was around 8 km/h. The Urutu also would have had access to a remote tire pressure control system to allow pressure regulation of the tires from within the vehicle.
Its gradeability was around 60%, with the maximum side slope being 30%. The Urutu had a ground clearance of 0.375 m (1.2 feet) and could cross a 0.6 m high vertical obstacle. It had an operational range of 850 km with a 380 l fuel tank. It could also be airlifted, much like all other versions of the Urutu.
The vehicle was 6 x 6 driven, of which the rear 4 wheels were part of the Boomerang suspension. The Boomerang suspension, in combination with the Engesa 2 speed transfer case, would enable the Urutu to cross challenging terrain and provide maximum traction in most situations. The power of the engine was distributed to a differential on the front side of the vehicle, and a differential in the rear. The rear differential drove the Boomerang suspension with a single axle, which is what makes it such an ingenious design.
Turret and Armament
It is unknown if the turret for the Gun/Mortar was made by Engesa or if they bought it from Thomson Brandt, which sold the mortars. Arguments could be made for both possibilities. The turret is not much more than a few plates welded together and a gun mount, something which Engesa would definitely be capable of building. The other perspective is that it was just a single prototype and that Engesa may have figured that they would design a turret themselves when they actually sold one. In either case, the turret seems to be very thinly armored. If the turret was designed by Engesa, it is possible that it was created from bimetal steel.
The turret was open-topped, with the gun/mortar located in the front middle. To the left of the gun, on the interior side, seems to have been some sort of gun laying device. The turret offered one sighting periscope with x3 magnification fitted to the gun mount. A 7.62 mm or .50 caliber pintle mounted machine gun was offered as an option as well.
The mortar could be both muzzle and breech loaded, with safety systems preventing double loading and a lock on the firing pin on an improperly closed breech. It was a smoothbore gun weighing 82 kg and with a maximum recoil force of about 17,000 N (1,700 kg). The recoil mechanism consisted of a large recoil spring which was coiled around the barrel exterior. The gun/mortar could provide direct fire up to 300 m and indirect fire up to 2,600 m while offering a gun depression of -15° and +75°.
The gun/mortar had access to high explosive, high explosive anti-tank, smoke, illumination, and canister ammunition. The vehicle had 82 rounds at its disposal and 2,000 7.62 or 600 .50 caliber machine gun rounds, depending on which armament was selected for the pintle mount, if one was bought in the first place.
Ammunition Type
Model
Performance
Muzzle Velocity
Range
High Explosive
Mle 72
–
205 m/s
2600 m
High Explosive Anti-Tank
60 mm CC
Up to 200 mm penetration
200 to 255 m/s depending on sources
500 m
Smoke
Mle 61
–
–
2050 m
Illumination
Mle 63
Minimum burning period of 30 s with a 150 m light radius
–
1700 m
Canister
60-132-C1
132 balls of hardened lead buckshot covering 25 m2 at 50 m
–
100 m
Fate
It simply seems that the large supply of the AMLs saturated the market and that countries were not interested in reducing the troop transport capacity from 12 soldiers to just 8. Especially the latter reason could cause issues with squad sizes within armies. In addition, it is unknown how many mortar rounds were on-hand in the one-man turret, but considering the size and the significant compromise with transportable personnel, it is thought to be very little. This would mean that the gunner would have had to leave his turret and get ammunition from the hull to keep on firing. Even worse is that the turret bustle slightly overhung the two frontal passenger top hatches as well, rendering them useless. The fate of the single prototype is unknown, but it is quite likely that it was reconverted to a standard Urutu or scrapped.
Conclusion
The Gun/Mortar Urutu was perhaps one of Engesa’s most pointless vehicles. It did not make much sense on paper, nor would it likely have been a good vehicle in reality. The compromises needed to make the mortar carrier work seem to have been too significant to get any buyers for the concept. Not only that, the French had spent about a decade before the Gun/Mortar Urutu appeared in flooding the African and South American markets with 60 mm mortar armed Panhard AMLs which were arguably more effective vehicles.
The Gun/Mortar Urutu seems to have been not much more than trying to chip in on an already saturated market by putting the armament on a decent platform. It almost seems that the only reason it really existed in the first place, is that it was cheap to make and it was an extra variant for the Urutu platform for the sake of having more variants.
Specifications EE-11 Urutu 60 mm Gun/Mortar
Dimensions (L-W-H)
6.15 (20’) , 2.59 (8’) , 2.7 m (9’)
Total weight
13 tonnes (14.3 US tons)
Crew
2+8 (driver, commander and 8 passengers)
Propulsion
Diesel Mercedes Benz OM352A-S
Suspension
Boomerang suspension
Speed (road)
Around 95 km/h (59 mph)
Operational range
850 km (528 Miles)
Armament
HB60 60 mm gun/mortar
Armor
Hull
Front 12 mm (0.5 inch, Bimetal) at 70º
Front (Lower Glacis) 12 mm (0.5 inch, Bimetal) at 30º
Sides 8 mm (0.3 inch, Bimetal)
Rear 8 mm (0.3 inch, Bimetal) at 10º
Turret
Unknown
Produced
1 Prototype
Sources
Blindados no Brasil – Expedito Carlos Stephani Bastos
Engesa’s Marketing Brochures
Engesa’s User and technical manuals for the Urutu and Cascavel
Personal correspondence with Ex-Engesa employees Jane’s Armour and Artillery 1985-1986
Federative Republic of Brazil (1976-1988)
Tracked Bridge Layer – 5 Built (1 Prototype and 4 Production)
In 1973, Brazil began developing the X1 tank, which was completed later that year. From there, the vehicle would spawn multiple variants, from rocket launchers to anti-aircraft vehicles. Another variant of the X1 was the XLP-10 bridge laying vehicle. The Brazilian Army decided it needed a bridge laying vehicle built from an already existing platform, which ended up being the X1 platform. The XLP-10 was the first bridge layer to be designed in South America. In total, 5 bridge layers were built, of which 2 vehicles remain, one of which was recently restored to driving condition. In the end, the limited weight capacity of the bridge and the phasing out of the X1 family caused the XLP-10 to suffer the same fate.
The X1 Project
The first X1 vehicle was developed and presented at the Brazilian Independence Day Parade on September 7th 1973. The X1 was a modernization of the M3 Stuart carried out by the Parque Regional de Motomecanização da 2a Região Militar (PqRMM/2, Regional Motomecanization Park of the 2nd Military Region), together with Bernardini and Biselli, two Brazilian private companies. The PqRMM/2 was responsible for the development of the wheeled vehicles, but also for the tracked vehicles of the Brazilian Army at the time, and was under the supervision of the Diretoria de Pesquisa e Ensino Técnico (DPET, Army Research and Technical Educational Board), which coordinated the projects.
The tracked vehicles were researched and developed by a team of engineers within the Army and PqRMM/2, which were part of the Centro de Pesquisa e Desenvolvimento de Blindados (CPDB, Centre for the Research and Development of Tanks). The CPDB was a study group of Army engineers which analyzed the possibilities of producing tanks domestically. The first goal was to develop a new family of light tanks using the M3 Stuart as its basis. One of the vehicles which would form part of what we now know as the X1 family, was the XLP-10.
The Institutional Competition
When exactly the XLP-10 project was initiated is unknown. What is known is that the project seems to have begun in the first half of the 1970s, likely at some time between September 7th 1973 and September 29th 1974. The theory behind this is that the first X1 prototype was presented on the earlier date and the first scale model of a bridge laying vehicle was seen at Bernardini on the later date. The X stood for prototype, the LP for Lançador de Ponte (Bridge Layer, literally Bridge Launcher), and the 10 for the length of its bridge, which was 10 m.
Around the mid-1970s, the Brazilian Army figured that it would also need bridgelaying vehicles for their X1s (and eventual X1A2s) to use them more flexibly and to allow the tanks to operate in more difficult terrain. As a result, the Army tasked the Instituto Militar de Engenharia (IME, Institute of Military Engineering) with carrying out a number of initial studies on such vehicles. The IME concluded that such a vehicle could be built on the hull of an M3 Stuart, which was fairly convenient from a logistical point of view. IME proposed an electric bridge laying system, for which Bernardini would be contracted to manufacture. It is believed that this study was done around 1974, and the mock-up at Bernardini was for the electric design.
At the same time as or a few years after the initial design of IME’s bridge layer, however, the Instituto de Pesquisas e Desenvolvimento, (IPD, Research and Development Institute) authorized a working group of PqRMM/2 engineers, who were part of the CPDB branch of the complex, to design a bridge laying vehicle on the Stuart/X1 platform as well. The CPDB engineers, led by the then Captain Guy Ubijara Meyer, opted for a hydraulic bridge laying system instead and would contract Biselli to manufacture theirs.
What is interesting is that the IME had no idea that a parallel development was going on. It seems that the DPET, which was supposed to coordinate the efforts of the IME and the IPD, had decided to create a competition between the two institutes to see which could come up with the best design. At some point, the CPDB engineers figured out (or knew the entire time) what was going on and got their hands on the IME design. The CPDB engineers went on to write up a report that put their hydraulic design next to the electric design of the IME and essentially compared the designs.
The report pointed out that the electric design from the IME was incapable of fully automatic bridge laying, as the crew had to get out of the tank to manually couple or decouple the cables from the bridge. But also that the design had an excessive height and the telescopic bridge laying system was not functional, as it could not get low enough to lay the bridge over shallow river beds. The report was passed on to the DPET, which decided to go for the hydraulic design in order to concentrate all the efforts into a single project.
The Captain, The Soviet, and The Company
The project of the CPDB was managed by Captain Guy Ubijara Meyer, who is credited with the design of the bridge itself. Captain Guy Ubijara Meyer had been a cadet at the Academia Militar das Agulhas Negras (AMAN, Black Needles Military Academy), comparable to West Point. He graduated top of his year at the AMAN, as part of the Ordnance branch, with a 9.439 score on December 19th 1964.
Captain Guy Ubijara Meyer then went on to again graduate top of his year at the IME at the auto mechanical course with a 9.28 in 1972. He received the Marshal Hermes medal from Emílio Garrastazu Médici, who was the president of Brazil at the time. The students showed the president both a mechanical mule that they had made and the X-40 rocket which would be used to arm the XLF-40 about 4 years later. Sadly, no picture of Guy Ubijara Meyer is available.
It seems that the Captain then ended up at the PqRMM/2, where he designed the bridge of the XLP-10 and led the project. Another interesting person is a Soviet Major, Nikolai Lebedev, who did all the structural calculations for the bridge. The writer has been unable to track down more information on the Soviet Major.
Although the CPDB had initially opted for Biselli to construct the XLP-10, Bernardini would be the company to carry out the project instead, as Biselli had stepped away from large defense projects. The exact reasons are unclear, but there are some statements that Biselli had some internal struggles, and Bernardini demanded more recognition for their efforts in the X1 project. In addition, it is also suggested that Biselli saw limitations in the defense industry and decided that focussing on the civilian industry was more profitable, while taking on more of a support role in the defense industry. With Biselli quitting the project, all tank development would be taken on by Bernardini.
Building Bridges
The CPDB decided that an X1 hull would be used as the main platform for the XLP-10, for which they used an M3A1 with serial number EB11-030 as their base vehicle. It was to lay a 10 m long aluminum bridge with a width of 2.65 m and a weight capacity of 20 tonnes. The vehicle used a rail system to move the bridge forward and a hydraulic powered cantilever system to lay the bridge in place in 3 minutes.
An outrigger located at the front of the hull, which was powered by two hydraulic pistons, was to prevent the XLP-10 from flipping over due to the weight of the bridge when fully extended on uneven terrain. This system is exactly the same as the XLF-40’s frontal outrigger system, although the XLF-40 used it for stability of fire instead, as it also had the outrigger on the rear. The hull machine gun was removed for a co-driver and a double hatch system was added for him, like for the driver. This was meant to make it easier for the co-driver to exit the vehicle to assist in laying the bridge if possible and needed.
The hull also differed structurally from the X1’s in a number of details. It forewent the hooks which were placed on the angled front plates towards the side and two plates were welded on top instead to support the front of the bridge. In addition, a profile structure was constructed on the rearmost plate to support the bridge in the rear. Between the two support points, behind the cantilever system, 4 smoke launchers were installed as well.
When exactly construction began is unknown. Considering how quickly the PqRMM/2 team managed to build some of these prototypes (the XLF-40 was built in just 2 months), it is quite likely that construction might have begun only a couple of months before the XLP-10 was first presented on September 7th 1976. A picture from July 20th 1976 shows the construction of the bridge itself in advanced stages. The finalization of the bridge construction, the potential conversion and the mating may have happened in between those two dates, although the conversion is uncertain.
The materials of the bridge were provided by the Brazilian subsidiary of the Canadian aluminum company Alcan. Supposedly, they also helped with the design and construction of the bridge, or may have done the construction entirely.
The XLP-10 was presented on the September 7th 1976 Independence Day Parade alongside the X1A1 and the XLF-40. Interestingly, of these 3 vehicles, only the XLP-10 would be produced in a considerably modest production run of 5 vehicles, including the prototype. After the prototype was presented, it seems to have been tested around October 1976 in the Campinas region near São Paulo.
The prototype went to the AMAN and one of the 4 production vehicles went to the Escola de Material Bélico (ESMB, School of War Material), both meant to essentially teach the Brazilian soldiers about bridge-layers and how to operate and or use them. The 12th BECmb (Batalhão de Engenharia de Combate, Combat Engineering Battalion), located in Alegrete, in the state of Rio de Janeiro, received two XLP-10’s on October 30th 1981. The 6th BECmb, located in São Gabriel, in the state of Rio de Janeiro, received a single XLP-10 at an unknown date, but before 1983 and likely around late 1981 to early 1982 as well.
The XLP-10 in Detail
The XLP-10 weighed 17 tonnes combat-loaded (18.7 US tons) and 14.4 tonnes (15.9 US tons) without the bridge. It was 11.2 m (36.75 feet) long with a bridge and 5.85 m (19.2 feet) long without the bridge. The vehicle was 2.9 m (9.5 feet) wide and the hull was 2.4 m (13.1 feet) wide. The XLP-10 was 2.5 m (8.2 feet) tall and 1.5 m (4.9 feet) tall without the bridge. It had a crew of two, with the driver located on the front left of the hull, the co-driver on the front right of the hull.
Hull
The hull of the XLP-10 was a slightly lengthened and modified M3A1 Stuart hull. As such, the overall protection for the XLP-10 hull remained the same as that of the M3. The thickness of the plates which were used to lengthen the hull is unknown. The upper front plate of the XLP-10 had an armor thickness of 38 mm (1.5 inch) at 17º vertical, a middle front plate of 16 mm (0.6 inch) at 69º, and a lower front plate of 44 mm (1.7 inch) at 23º. The frontal cheek plates transitioning to the side plates were 28 mm (1.1 inch) thick. Its sides were 25 mm (1 inch) thick and angled at 10 degrees from vertical, while at the engine bay the sides consisted of two plates of 25 mm spaced from each other. This is because in the crew compartment, a hole was grinded out of the original plates for use as stowage, while this did not happen at the rear. The rear armor was the same as the M3 Stuart, being 25 mm (1 inch). The top plate was 15 mm (0.6 inch) thick and the floor plate gradually decreased in thickness from 13 mm at the front to 10 mm (0.5 to 0.4 inch) in the rear.
The rest of the XLP-10 had a very similar layout as the Stuart. It had two headlights, one on each side of the front mudguards, two towing hooks on the front hull, two driver style double hatches and, as a result, no hull machine gun. Interestingly, a set of three presiscopes for both the driver and co-driver were installed on the top hull. This was, for example, not carried out on the XLF-40. The hull also featured two plates sticking out over the hull top for the bridge structure to rest on at the front hull and a profile structure on the rear, which included wheels for the bridge to move over. Four smoke launchers were installed in between these profiles on the hull top.
The XLP-10 had two hydraulic pistons on the front hull, one on each side. These pistons were fixed on a pivot, which allowed them to turn facing the ground when the pistons were utilized. The foot of the outrigger on which the XLP-10 was stabilized had a rotating bar attached to it and to the hull, which caused the pistons to face the ground as the rod of the piston made a complete stroke. This design differed from the XLF-40, as the XLF-40 had a foot per piston instead of a foot for two pistons. This most likely had to do with the XLF-40 using the tow feet to provide a more stable and level ground of fire instead of preventing the vehicle from flipping over.
Mobility
The XLP-10 was powered by a Scania-Vabis DS-11 A05 CC1 6-cylinder in-line diesel engine. This engine produced 256 hp at 2,200 rpm, giving the vehicle a horsepower per tonne ratio of 15.4. It used the same, but revised and locally produced, 5 forward and 1 reverse gearbox, transmission and differential as the original Stuarts. The XLP-10 would have had a top speed of about 55 km/h (34 mph) on roads, but would most likely be much slower when it mounted the bridge. The vehicle had an operational range of 520 km (323 miles) and about 300 km (186 miles) on uneven terrain.
The XLP-10 used a copied and slightly altered VVS suspension system from the 18-ton M4 artillery tractor. It had 4 road wheels divided over two bogies, with 2 bogies per track, two return rollers on each side, a drive sprocket in the front and an idler wheel on the rear. The 18-ton M4 suspension gave the vehicle a ground pressure of around 0.59 kg/cm2 (8.4 psi). It had an on-ground track length of about 3.22 m (10.6 foot) and could cross a trench of 1.2 m (3.9 foot).
The Bridge
The XLP-10 used what is known as a horizontal or cantilever bridge laying system. The advantage of such systems is that the bridge does not extend vertically and is thus less likely to be spotted from a distance. The bridge was 10 m (33 feet) long and could be used to bridge an 8 m (26 feet) long gap. It had an external width of 2.65 m (8.7 feet) and an internal width of 1.36 m, with each lane being 0.64 m (2 feet) wide. The bridge was made from aluminum and weighed 2.6 tonnes (2.87 US tons). An additional lane could be laid against one of the sides to allow jeeps and similar vehicles to cross as well. This additional lane was stored on the side of the hull. Through the hydraulic cantilever system, the bridge could be laid on terrains 0.3 m (1 feet) below ground level and in 3 minutes.
The bridge could carry a maximum weight of 20 tonnes (22 US tons), which for all intents and purposes barely held the X1A2, as it weighed 19 tonnes (21 US tons). It was also noted that the bridge had issues carrying wheeled vehicles, which might be because of the smaller surface area of the tyres compared to tracks.
In essence, the bridge structure consisted of two main structures. The inner supporting structure and cantilever, which is known as the main frame, on which the bridge rested, would retract back and forth, and which laid the bridge on the ground. The other structure was the bridge itself. The bridge rested on top of wheels which were attached to the cantilever structure of the XLP-10. A C-shaped beam with a roller track was attached to both inner sides of the lanes. These tracks were driven by a hydraulic motor which drove the bridge forward and backwards through a sprocket.
When the bridge was laid, vehicles could also drive over the cantilever frame of the XLP-10 across smaller gaps. This could be done if the 1.5 m (4.9 feet) high XLP-10, without the bridge, would position itself inside a gap, with vehicles passing on top. The weight limit for this type of bridging is unknown. The cantilever could also be used as a crane, holding a maximum of 4 tonnes (4.4 US tonnes) to the beams.
The Hydraulics
The hydraulic system essentially powered 3 main components, which were the hydraulic motors for the bridge, the pistons of the cantilever, and the pistons of the outrigger, which prevented the XLP-10 from falling over. It was powered by a hydraulic pump which was directly coupled to the engine through gears and controlled from the inside by three levers.
To protect the system, a solenoid valve with an electric sensor was added to prevent the activation of commands in the wrong order. The flow and pressure were regulated with valves and the hydraulic fluid was stored in a 50 liter (13.2 US gallons or 88 UK pints) reservoir. The fluid was pumped to the bridge through a tube which was attached to the rear of the vehicle.
How the Bridge Got Laid
The process of laying the bridge essentially consisted of 4 steps. The XLP-10 would drive up to the gap and let the pistons of the outriggers fully extend in order to keep the vehicle in place. Then the bridge would be fully extended through the hydraulic engines. The cantilever pistons would then push the cantilever upwards and thus cause the bridge to be laid on the ground. Finally, the bridge was decoupled. The bridge would be picked up with the above mentioned process but reversed. This process would take about 3 minutes and could be carried out completely by the driver alone, although the co-driver would step out of the vehicle to guide the process if the situation allowed this.
Service and Fate
The XLP-10 was distributed to two combat units, which were the 6th BECmb and the 12th BECmb, both located in Rio de Janeiro state. The 12th received 2 XLP-10s on October 30th 1981 and supposedly used them the most. The 6th BECmb likely received their single XLP-10 around the same time, but only started to employ it in 1983 for unknown reasons.
Around February 29th 1984, all the XLP-10s seem to have been redesignated from EB13 to EB20 vehicles. EB13 was used for specialized armored vehicles. The writer was unable to find for what the EB20 designations was used, as it appears on multiple vehicles, including jeeps. It is possible that EB20 was specifically made for the bridgelayers at the time, or for distinct logistical vehicles. In any case, this EBXX system was slowly phased out in the 1980s and completely abolished from at least 1988 on.
Unit
Registration post-1984
Registration pre-1984
EsMB
EB20-615
EB13-015
IPD
Never seems to have been redesignated
EB13-030
6th BECmb
EB20-619
EB13-019
12th BECmb
EB20-620
EB13-020
12th BECmb
EB20-621
EB13-021
The XLP-10 suffered the same mechanical issues of the original X1, mostly due to the vehicles being modernized from a thirty year old hull. Among these issues were a flawed single disc clutch, locally produced volute springs that broke and would later be replaced by imported springs, and the swing arms of the track idler starting to crack when the X1 family vehicles moved at full speed.
This final problem was perhaps less severe on the XLP-10 than the X1, as the XLP-10 would likely move much slower and would be less inclined to overcome difficult terrain due to its bridge. Eventually, the problem which caused the cracking was found: the copied 18-ton tractor suspension used a grease cup instead of oil lubrication for the bearing of the idler. Since grease has a higher viscosity than oil, it was unable to properly flow and lubricate the bearing, causing the idler wheels to get stuck and subsequently tear the swing arms apart. In June 1984, this issue was resolved by returning to oil lubrication. Initially, it was planned for Bernardini to produce 58 new idlers for the 52 X1s, the XLF-40, and the 5 XLP-10s, but the costs were so high that this was abandoned.
The XLP-10 had two issues of its own apart from the X1 issues it inherited. The bridge had difficulties supporting wheeled vehicles, likely due to wheeled vehicles having worse and more concentrated weight distribution compared to tracked vehicles. The other issue was that the hydraulic pistons of the support outrigger did not always extend uniformly, which resulted in cracks.
The entire X1 family would be gradually replaced by the M41C in 1988, and would be decommissioned in July 1994. It is suggested that some X1s were used as training vehicles, as they were cheaper than the M41C.
Remaining XLP-10s
Which XLP-10s remain to this day is a bit unclear. What does seem somewhat certain is that the two XLP-10s from the 12th BECmb where still at their unit in 2007, but already without their bridges. According to the book Brazilian Stuart, all 4 production vehicles were scrapped. This does seem to be the case for the vehicles of the 12th, but does not seem to completely hold true, as two vehicles have survived.
The first is the XLP-10 which currently resides at the Panambi Military Museum. The bridge of this XLP-10 comes from the 6th BECmb, but the hull has been painted over and it is not completely certain if the hull and bridge belong to the same vehicle. The writer has attempted to contact the museum about this, but sadly they would not provide any answers regarding their vehicle. As such, the writer currently assumes that the vehicle is from the 6th BECmb.
The second vehicle was originally located at the CIBld, but has been restored to driving condition in Alegrete, along with other vehicles, such as the Osorio and the Tamoyo 1. This vehicle has been painted over as well, and could thus be either the prototype or the XLP-10 from the EsMB. Considering the book Brazilian Stuart specifically states that all production vehicles were scrapped, it is possible that this is actually the prototype. However, Brazilian military armor expert Expedito Carlos Stephani Bastos states in an article from 2005 that the XLP-10 from the EsMB was located in Rio Grande do Sul, the state where the CIBld is located. Expedito also states that the prototype was located at the CTEx (Centro Tecnológico do Exército, Army Technology Centre) in Rio de Janeiro and a production vehicle was at the AGSP (Arsenal de Guerra de São Paulo, War Arsenal of São Paulo).
In any case, which vehicle is which will remain somewhat of a mystery it seems. What is at least certain is that two XLP-10s remain, of which one carries the bridge of the 6th BECmb. The XLP-10 from the CIBld was restored and presented during the parade of March 24th 2022 for the transition of command of the 3rd Army from General Hertz Pires do Nascimento to General Sergio Luiz Tratz.
The XLP-20
The XLP-10 would also lead to another bridge layer project on the M4 Sherman platform. The so called XLP-20 was to use an 18.5 m long bridge which could hold up to 30 tonnes. Designs were made in 1977, but eventually went nowhere. The reason for this may be the smaller number of 53 Shermans that were available, which would mean that the Brazilian Army could experiment less with those.
Conclusion
The XLP-10 was the only successful support variant of the X1 family, which was likely due to its practicality, making it possible to cross water streams or gaps which were normally circumvented instead. Although the XLP-10s were phased out along with the rest of the X1 family, it does seem that it left its mark well enough for Brazil to acquire bridge layers for their Leopard 1s in the mid-2000s.
The glaring issue of the XLP-10 is that its weight capacity was lacking. It was pretty much limited to supporting Stuart based regiments and wheeled vehicles caused issues with the bridge as well. These issues were to be fixed with the XLP-20 project which ended up being canceled in the end. All in all, the XLP-10 was a practical project and the first of its kind in South America, albeit limited in capacity.
XLP-10 Specifications
Dimensions (L-W-H)
11.2 m (36.75 feet) long with the bridge and 5.85 m (19.2 feet) long without
2.9 m (9.5 feet) wide in total and the hull was 2.4 m (7.9 feet) wide
2.5 m (8.2 feet) tall with bridge and 1.5 m (4.9 feet) tall without
Total weight
17 tonnes (18.7 US tons) and 14.4 tonnes (15.9 US tons) without the bridge
Crew
2 (driver and co-driver)
Propulsion
Scania-Vabis DS-11 A05 CC1 6-cylinder in-line 256 hp diesel engine
Suspension
Bogie suspension
Speed (road)
55 km/h (34 mph)
Operational range
520 km (323 miles)
Armament
None
Bridge
10 m (33 feet) long aluminum bridge, 2.65 m (8.7 deet) wide, capacity of 20 tonnes (22 US tons)
Armor
Hull
Front (Upper Glacis) 38 mm (1.5 inch) at 17º
Front (Middle Glacis) 16 mm (0.6 inch) at 69º
Front (Lower Glacis) 44 mm (1.7 inch) at 23º
Sides 25 mm (1 inch)
Rear 25 mm (1 inch)
Top 15 mm (0.6 inch)
Floor 13 to 10 mm (0.5 to 0.4 inch)
Produced
4 + 1 prototype
Special thanks to Expedito Carlos Stephani Bastos, the leading expert of Brazilian armored vehicles https://ecsbdefesa.com.br/, Jose Antonio Valls, an Ex-Engesa employee and expert in Engesa vehicles, Paulo Bastos, another leading expert of Brazilian Armored vehicles and the author of the book on Brazilian Stuarts and the website https://tecnodefesa.com.br, Adriano Santiago Garcia, a Captain in the Brazilian Army and ex-company commander on the Leopard 1 and ex-lecturer on the Brazilian Armored School, and Guilherme Travassus Silva, a Brazilian with whom I was able to endlessly discuss Brazilian Vehicles and who was always willing to listen to my near endless ability to talk about them.
Sources
Brazilian Stuart – M3, M3A1, X1, X1A2 and their Derivatives – Hélio Higuchi, Paulo Roberto Bastos Jr., Reginaldo Bacchi
Blindados no Brasil – Expedito Carlos Stephani Bastos
Lançador de Ponte XLP-10 – Expedito Carlos Stephani Bastos
Lançador de Ponte XLP-20 – Expedito Carlos Stephani Bastos Jane’s Light Tanks and Armoured Cars of 1984
Worldwide Tank Fire-Control Systems – CIA http://www.lexicarbrasil.com.br/
Personal correspondence with Expedito Carlos Stephani Bastos
Personal correspondence with Paulo Roberto Bastos Jr.
Caiafa Master
Engesa brochures and manuals
Cockerill brochures
TM 9-785 18-Ton High Speed Tractors M4, M4A1, M4C, and M4A1C – US Army April 1952. Stuart: A history of the American Light Tank, Volume 1 – R.P. Hunnicutt
Tecnologia Militar Brasileira magazine
Federal Republic of Germany (1959)
Tank Destroyer – 2 Prototypes Built (1 Armored and 1 Mild Steel)
When the West German Army, known as the Bundeswehr, was reformed, the decision was made to develop a new generation of Jagdpanzers. As the founding officers of the Bundeswehr had roots within the old Wehrmacht of the Second World War, it is perhaps no surprise that the concepts of Jagdpanzer and Sturmgeschütz were revived. As the concepts of these vehicles had already started to merge together into a single armored casemated support and tank destroying vehicle, the upcoming Kanonenjagdpanzers ended up much in the same way.
Development of the new Jagdpanzers began in 1957. The Swiss designed HS 30 Infantry Fighting Vehicle was selected to be converted. The reason was likely because the Germans planned to operate 10,000 of these IFVs and commonality of hulls would have been quite useful. What was designated as the Kanonenjagdpanzer 1-3 performed abysmally in trials, however, with its very conversion from an IFV causing most of the issues. While the Kanonenjagdpanzer 1-3 would not be successful, it did lay out the path for the future Kanonenjagdpanzers.
Designation
An interesting detail is the designation of the Kanonenjagdpanzer 1-3 (Literally Cannon tank hunter). It is referred to officially as Jagdpanzer 1-3, but it also frequently receives the name Kanonenjagdpanzer HS 30 or Jagdpanzer Kanone HS 30 (Tank hunter cannon). The same also counts for the Jagdpanzer 4-5, which is frequently referred to as just Kanonenjagdpanzer. The reason for this is the development of the ATGM armed Jagdpanzers, which were also known as Jagdpanzers (like the Jagdpanzer 3-3), but also referred to as Raketejagdpanzer or Jagdpanzer Rakete (Missile tank hunter or Tank hunter missile).
There does not seem to have been a definitive convention on if Kanonen should come before or after Jagdpanzer, as the manuals refer to Kanonenjagdpanzers and the manufacturing plates inside refer to them as Jagdpanzer Kanone. The manuals actually list multiple designations for the Kanonenjagdpanzer which went into service, namely: Kanonenjagdpanzer and Panzer, Jagd-, Vollkette mit Kanonen 90 mm, and JPZ 4-5 (Cannon tank hunter and Tank, Hunter-, Tracked with 90 mm Cannon, and JPZ 4-5). It mainly seems that Jagdpanzer 4-5 was used as part of the official designation and that Kanonenjagdpanzer was used to make it easier to keep track of the different Jagdpanzers. The 1-3 and the 4-5 are type designations for specific vehicles.
The important part is that both the Rakete and the Kanone types were Jagdpanzers and that Rakete and Kanone were simply used to distinguish between the armaments. In this article, Kanonenjagdpanzer 1-3 will be used, as it will make it clearer that this is about the cannon armed vehicle. Please keep in mind that Kanonenjagdpanzer 1-3 was not the official designation though.
The Founding of the Bundeswehr
Following the end of the Second World War, the German Reich was divided into four occupation zones. As a result of the Potsdam Conference which took place from July to August 1945, France, Great Britain, and the United States occupied West Germany and the Soviet Union East Germany. The four occupying powers decreed on August 30th 1945, under Order no. 1, that the German Army was dissolved, with full dissolution of the armed forces under Law no. 8 on November 30th 1945.
In the years following the occupation of Germany, a large string of events would open the door for German rearmament. The Cold War would slowly start as a result of the Soviet spread of Communism through satellite states, the Truman Doctrine, the Berlin Blockade of 1948 to 1949, the detonation of the first Soviet atomic bomb, the formation of the West and East German states, the formation of NATO, Communist victory in the Chinese Civil War, and the Korean War from 1950 to 1953.
The Bundesrepublik Deutschland (Federal Republic of Germany or commonly known as West Germany) was formed on May 23rd 1949. With the beginning of the Korean War a year later, a large group of ex-Wehrmacht officers met at the Himmerod Abbey to discuss the formation of a West German Army. In 1951, the Bundesgrenzschutz, or BGS, was formed as a lightly armed police force for the patrol of the West German border with the Soviet-aligned states.
Eventually, after a failed European Defence Community which had attempted to put all the European Armies under a single overarching command structure, Germany was invited to NATO and joined on May 5th 1955. On June 7th 1955, the West German Federal Ministry of Defence was formed and, on November 12th, the Bundeswehr was created with the enlistment of its first 101 volunteers.
Jagdpanzer and Sturmgeschütz during the Second World War
The newly formed Bundeswehr started forming its doctrine and equipment by drawing from previous experiences of the Second World War. The Kanonenjagdpanzers were one of these products which could trace back their lineage to doctrine and vehicles from the previous war, where the Jagdpanzer and Sturmgeschütz proved their worth.
At the start of WW2, a fairly clear distinction could be made between the Panzerjäger and Sturmgeschütz. The Panzerjägers started off as lightly armored self-propelled guns for anti-tank purposes, such as the Marders, while the StuGs were more heavily armored and meant to support the infantry. The StuGs were initially not meant to engage enemy tanks unless they had to in self-defense, as they were still armed with the short barreled L/24 7.5 cm cannon.
But this distinction already started to fade as early as 1942, when the first long barrel 7.5 cm L/43 armed StuGs entered production and were fielded with the StuG units. The StuGs became able to effectively fight tanks and, in March 1942, they were used to great effect in the first deployment of the StuGAbt 197 in the defense against Soviet massed tank assaults. The StuGs would function not only as infantry support vehicles, but with the improved firepower, also take on the role of a Panzerjäger when needed.
In fact, the Jagdpanzer IV, originally designated as Sturmgeschütz n.A and meant to replace the StuG III, ended up with a Panzerjäger designation after a proposal from Heinz Guderian. During the mid to later stages of the war, Panzerjäger units transitioned from their light vehicles to more heavily armored casemate style tanks instead. From 1944 on, Panzerjäger units would be filled with Jagdpanzer IVs, while the StuG units had to make do with the StuG IIIs until they started receiving Jagdpanzer IVs in limited numbers at the very end of the war. In essence, the Jagdpanzer IVs would be more effective for the German Army functioning as Jagdpanzers, while the StuG III would remain reasonably effective as an infantry support vehicle with anti-tank capability.
But the similarity between the StuG and the Jagdpanzer IV cannot be overlooked and they did end up performing more or less similar tasks due to them having similar capabilities, with the latter ending up in StuG units as well. It took until August 1944 for the Jagdpanzer IV to get stronger anti-tank capabilities, after it was armed with a more powerful 7.5 cm L/70 gun and thus served more fittingly as a Panzerjäger. As the war reached its conclusion in 1945, the distinction between Sturmgeschütz and Jagdpanzer classification became non-existent, as 100 7.5 cm L/70 armed Jagdpanzer IVs were distributed over 19 different StuG Brigades from January to March 1945. The merging of these two separate doctrines into a single vehicle fitting both purposes seems to have been the main inspiration for the usage of the later Kanonenjagdpanzers.
A New Generation of Jagdpanzers
The Bundeswehr had a lot of catching up to do when it was founded in 1955, as the Germans had not designed, built, or operated armored equipment in the past 10 years. On top of not having designed new equipment, the Germans were lacking new equipment in general to outfit their new Army. The Bundeswehr started off by acquiring foreign equipment, such as the American M41 Walker Bulldog and M47 Patton, but also the French Hotchkiss SPz Kurz Typ 11-2 and Swiss Hispano-Suiza HS 30 infantry fighting vehicle.
Besides acquiring new equipment, the Bundeswehr also had to figure out what they wanted to do with their Army from a doctrinal point of view. Initially, it seemed that the Germans more or less looked at their Army structure of World War 2, picked the concepts that worked and then adjusted those to better fit the time period of the Bundeswehr. Two of these concepts which had worked were the Jagdpanzers and StuGs.
The Bundeswehr returned to the Jagdpanzer IV concept, which had functioned as both a Panzerjäger and Sturmgeschütz, for their new anti-tank vehicle. The Kanonenjagdpanzers would be the spiritual successor to the Jagdpanzer IV and serve mainly as Jagdpanzers in anti-tank battalions within armored infantry brigades and mountaineer brigades, but fill a role similar to the StuGs in anti-tank platoons within the smaller armored infantry and mountain battalions. The West Germans decided that the newly acquired HS 30 (SPz Lang) was to function as the basis for their new Jagdpanzer.
The HS 30
When the Bundeswehr was founded, it sought to find a new type of armored personnel carrier to equip its troops. Based on trials with designs such as the American M59 and the French AMX-VTP and on experiences of WW2, a new concept of APC was to be introduced. The Schützenpanzer (can be translated as armored personnel carrier or infantry fighting vehicle, although it is seen as an IFV) concept was born.
The Germans did not yet have the capability or an industry ready to design such a vehicle however. Perhaps surprisingly, the contract for the new Schützenpanzer went to the Swiss branch of the company Hispano-Suiza, which had been founded in 1938. Hispano-Suiza did not have any experience in the design of tracked vehicles and had not even built a working prototype when it secured the contract. In fact, only a rough design sketch and a wooden scale model were made when the contract for the acquisition of as many as 10,680 vehicles was signed on July 5th 1956.
The fact that a company with no experience in designing tracked vehicles managed to obtain a 10,000 vehicle contract without even building a functioning prototype or even providing production sketches raised some eyebrows. When the first prototypes in 1957 arrived, they performed inadequately and the HS 30 would remain faulty, as certain design errors of the driver train were never really fixed. When the Jagdpanzer program was initiated in 1957, the number of HS 30s, which had been cut down to a still significant 4,412 vehicles, still seemed to be considerable enough to attempt to build an HS 30 based Jagdpanzer for potentially ease of logistics.
The Bundeswehr ended up receiving 2,176 vehicles, after the initial order of 10,680 vehicles was cut down over the years due to inadequacy and delays of the program. The HS 30 program would eventually turn into the largest acquisition scandal of the Bundeswehr and the German Government when journalists of the Frankfurter Rundschau and the Deutsches Panorama would connect the acquisition with significant bribes to officials in key positions and the CDU (Christlich Demokratische Union Deutschlands, Christian Democratic Union of Germany).
Designing the New Kanonenjagdpanzer
Already in October 1955, the Bundeswehr considered the acquisition of 2,820 Kanonenjagdpanzer armed with a 90 mm gun. The development of the new generation of Jagdpanzers began in 1957. It is likely that the project was initiated in 1957, as the HS 30 hull entered its first trials and was thus available for conversion. A project known as the Spähpanzer 1C (Reconnaissance tank 1C) on the SPz Kurz hull would be initiated as well. The later project was also known under the designation of Spähpanzerjäger (Reconnaissance tank hunter), as it would carry out reconnaissance duties and have the armament to take on enemy tanks.
The HS 30 design was altered in a fairly logical way, as the original troop transport compartment was integrated into the fighting compartment. The front structure of the fighting compartment was then heightened to 1.75 m, which was about 0.1 m smaller than the HS 30 IFV version. The smoke launchers were also moved from the upper hull plate to the engine bay top on both sides. The estimated costs were to be around 130,000 Deutschmark (About 31.000 US Dollars in 1957 and about 328.000 US Dollars in 2022) per vehicle.
It is possible that the Germans were convinced to arm the new Jagdpanzer with a 90 mm due to a French proposal for a Spähpanzerjäger in 1955. This project was a SPz Kurz with an early version of what seems to be the Hispano-Suiza H-90 turret of the future AML-90 and, according to author Rolf Hilmes, armed with a Mecar 90 mm low pressure gun, although the the French archives on the SP 1C say its a 90 mm D921. This early proposal, with promising penetration capabilities for a vehicle weighing less than 10 tonnes, would have likely made the German staff consider arming the new casemate Jagdpanzer with this 90 mm gun as well.
The gun selected for the Kanonenjagdpanzer 1-3 was the 90 mm DEFA D915, which was the same gun as that used on the AMX ELC. What is interesting is that sourcing claims that it shared the same gun as the AMX-13/90. This likely comes from the muzzle brake of the D915, which was similar to that of the CN90 F3 of the AMX-13. The caliber length however did not match, as the F3 had a caliber length of 52, while the D915 had a caliber length of 33.4. This seems to be further supported by the fact that the D915 was part of a program already around the mid-1950s, while the CN90 F3 would appear in the 1960s.
This is important because, in 1959, a full scale mild steel prototype and an armor steel prototype were built. It is likely that the mild steel prototype was built first to serve as something of a functioning mock-up before building a more expensive prototype for testing. The armor steel prototype was trialed in either 1959 or 1960. Peter Blume claims 1959, while Rolf Hilmes claims spring 1960. Considering the follow-up prototypes for the Kanonenjagdpanzer 4-5 would start to appear in 1960, it is possible that the trials were in late 1959 to spring 1960, as they were said to be somewhat extensive. The writer will as such continue with the idea that the vehicle was trialed from 1959 to spring 1960.
The Kanonenjagdpanzer 1-3 in Detail
The Kanonenjagdpanzer 1-3 weighed 13.72 tonnes (15.1 US tons) and was 7.06 m (23.16 feet) long including the gun and 5.56 m (18.24 feet) long excluding the gun, 2.5 m (8.2 feet) wide, and 1.75 m (5.74 feet) tall. The vehicle was operated by a four-man crew, consisting of the commander in the right rear of the casemate, the gunner in front of him, the loader on the left rear, and the driver in front of the loader.
Hull
The Kanonenjagdpanzer 1-3 used a welded structure converted from a HS 30. In essence, the vehicle integrated and heightened the troop compartment to make a single fighting compartment and to provide space for the commander, loader and the recoiling gun. The vehicle was constructed of armor steel plates with 30 mm (1.2 inch) of steel frontally and 20 mm (0.8 inch) on the sides.
The Kanonenjagdpanzer sported a headlight protected by a headlight guard on each side of the upper front plate and what seemed to be two blacklights next to those. Two side mirrors were located on the upper part of the upper front plate on each side. In the middle was the ball mounted cannon protected by a gun shield. If the gun shield used the same thicknesses as that of the Kanonenjagdpanzer 4-5, then the armor would range from 32 to 40 mm (1.25 to 1.57 inch) of cast steel. The vehicle also featured two tow hooks on the lower front plate.
The gunner, on the front right, had two periscopes available, while the driver on the left side of the vehicle had three. Of the two, only the driver seems to have had a hatch. The commander and his commander cupola were located to the rear of the gunner. The commander supposedly had a 7.62 mm machine gun mounted on the commander’s cupola, which would most likely have been an MG1. The loader had access to a large hinged hatch.
The engine was located on the right side of the rear. It is unclear how the leftover space of what used to be the entry for the transported troops was utilized. Perhaps it was turned into a stowage compartment, but this is speculation. What is an interesting design feature is that the entire rear piece from behind the engine was bolted on the main hull. This meant that, for maintenance, this rear piece could be removed, although the transmission remained fixed to the rear piece and, as such, the engine as well. The issue of this design was that 64 bolts had to be unblocked to pull off the rear and was a time consuming process.
Four smoke launchers were mounted on top of the right side of the engine bay and an antenna seems to have been mounted somewhere on the middle rear of the engine bay top. What exactly was mounted on the rear plate is unknown, but it is likely that it was fairly similar to what was on the HS 30. This would mean a jerry can mounting on the rear right with a towing cable wrapped around it. The exhaust pipe would be located under the jerry can and a number of hatches would be available on the left side of the rear. It is unknown if the double hatched door present on the HS 30 for the passengers was retained. The vehicle would have had two rear lights on each side of the rear plate, mountings for tools, and two towing hooks on the rear.
Mobility
The Kanonenjagdpanzer 1-3 was powered by the Rolls-Royce B81 MK80F 8-cylinder in-line 220 hp petrol engine. It was paired with a planetary gearbox with four speeds forward and 1 in reverse. The vehicle had a top speed of 51 km/h (32 mph) and a range of 270 km (168 miles). The vehicle had a hp to ton ratio of 16.
What is strange is that the Kanonenjagdpanzer 1-3 had a 280 l fuel tank while the HS 30 had a 340 l fuel tank (74 and 90 US gallons respectively), while both had a range of 270 km. It is possible that sourcing on the Kanonenjagdpanzer 1-3 is incorrect and that it should be a 340 l fuel tank.
The on ground track length was 3.03 m (10 feet), with a track width of 0.38 m, which gave the vehicle a ground pressure of 0.6 kg/cm2 (8.5 PSI). The Kanonenjagdpanzer 1-3 used a torsion bar suspension with five road wheels and three support rollers. The drive sprocket was located on the rear part of the suspension and the idler wheel on the front side. It could climb a 60% slope, traverse a vertical obstacle of 0.6 m (2 feet) tall, cross a 1.5 m (5 feet) wide trench, and ford for 0.7 m (2.3 feet) deep.
Armament
The Kanonenjagdpanzer 1-3 was armed with a 90 mm DEFA D915 low pressure gun. This meant that the gun’s penetration power would not come from kinetic energy ammunition, which relies on high velocities to penetrate a target, but on chemical ammunition instead. This means that all the penetration came from the round itself and was thus bound by the dimensions of the ammunition. High Explosive Anti-Tank shells (HEAT) are such rounds, as they use a jet of, for example, copper to penetrate through the armor.
The advantage is that high performing ammunition could be fired from very light platforms, as the HEAT ammunition could penetrate up to 320 mm (12.6 inch) of steel, while not having too much recoil force. The downside was that, due to the reduced barrel length and muzzle velocity, the guns tended to be much more inaccurate or even ineffective altogether at ranges further than 1 km (1,094 yards).
The D915 gun was 3.19 m (10.5 feet) long with a barrel length of 3 m (9.8 feet), giving it a caliber length of 33.4. It had a muzzle velocity of 700 m/s when firing a 7.5 kg (16.5 pounds) HEAT projectile with a penetration of 320 mm of steel flat at any range. The HEAT round had an effective range of 1 km. There is no clear information available on High Explosive rounds or High Explosive Squash Head rounds being developed or ready. The amount of ammunition the Kanonenjagdpanzer 1-3 could stow is unknown as well.
The 90 mm gun was aimed through a direct sight telescope on the right side of the gun and had no proper range finding equipment. The Kanonenjagdpanzer 1-3 did have access to infrared night vision equipment. The gun could be swiveled 30° from side to side and had an elevation of 15° and depression of -8°.
Aside from the main gun, the vehicle was armed with a hull top mounted 7.62 mm MG1 for the commander and a 7.62 mm on the left side of the main gun, in the gun shield.
Testing and Fate
The prototype was tested from 1959 to spring 1960 at the Panzerabwehrschule Munster (Anti-tank School Munster) and performed abysmally. The fighting compartment, which was only 1.54 m wide, proved too cramped for the crew and to properly operate the gun. If the gun was fully swiveled to the right, the driver could not fully steer the vehicle due to the breech. If the gun was swiveled 12° or more to the left, the gunner was trapped by the gun and could not operate it and thus the gun could not be fired. The loader was supposed to act as a radio operator but could not reach the radio.
The gun itself was also considered inadequate due to its limited range and bad accuracy. The ammunition was not NATO-standard, which was criticized for understandable reasons. The Kanonenjagdpanzer 1-3 also did not have a fan for the crew compartment, which caused unacceptable levels of CO in the fighting compartment, nor did it have an NBC system (Nuclear, Biological, Chemical warfare filtration system). Some parts of the ball mount were also not well enough protected against potential shrapnel.
The biggest issue was the main gun placement. As the gun was placed on the front of the hull on a vehicle not designed for this, a disproportionate amount of weight leaned on the front road wheels. The 26% increase of weight caused extreme wear on the bearings of the running gear and the running gear broke during the first trials after just 68 km (42 miles). Considering the initial requirement of the HS 30 was a horsepower to ton ratio of at least 20, it is likely that the ratio of the Kanonenjagdpanzer 1-3 was also criticized for being too slow.
All in all, these issues caused the rejection of the vehicle. But this did not mean the vehicle was not valuable. Lessons were learned on what not to do and concepts were tested. The overall design layout returned in the Kanonenjagdpanzer 4-5 and the gun shield design returned as well. It could be argued that the Kanonenjagdpanzer 4-5 was very roughly a larger Kanonenjagdpanzer 1-3 with better weight distribution and crew layout among other improvements, such as the gun.
The Kanonenjagdpanzer 1-3 reappeared in 1961, when the Spz 12.1 was undergoing tests. The SPz 12.1 was one of the proposals to replace the HS 30 and was designed by Ruhrstahl and the engineering firm Warneke. Ruhrstahl would be one of the participants in later proposals for the Kanonenjagdpanzer program and also the RU 251 light tank.
Parallel to the development of the Kanonenjagdpanzer 1-3 was the development of an ATGM (Anti-Tank Guided Missile) armed Jagdpanzer also converted from an HS 30 hull. ATGM systems were highly praised by the Bundeswehr, and as such, development of the Raketenjagdpanzer began in 1959 and the first prototype was built in the same year, known as Raketenjagdpanzer 3-3. Interestingly, according to Rolf Hilmes, one of the two Kanonenjagdpanzer 1-3 prototypes was converted into the Raketenjagdpanzer 3-3 prototype. Considering the version trialed was still around in 1961 (which was likely the armor steel prototype), it is possible that the mild steel prototype was used, as it would be easier to convert, as mild steel has better properties for machining.
This converted Raketenjagdpanzer 3-3 remains to this day at the Tank Museum in Munster where, with the right light angle, one can still see the original location of the 90 mm gun mount which has been welded shut. The fate of the other non-converted Kanonenjagdpanzer 1-3 is unknown. The Raketenjagdpanzer 3-3 was successful, with a production run of 95 vehicles. Due to it not having a gun at the front, all the weight balance issues were much easier to tackle. In addition, the SS.11 ATGMs would be less lacking than the 90 mm D915 gun.
Conclusion
The Kanonenjagdpanzer 1-3 was the first and unsuccessful attempt from the Germans to restart building anti-tank vehicles. The design seems to not have been much more than an attempt to see if they could get away with mounting a 90 mm gun on the HS 30 to save costs or as a doomed to fail but valuable test bed.
Very little actually changed conceptually from the initial design to the Kanonenjagdpanzer 4-5, except that everything was a bit bigger. The biggest issue apart from improper weight balance was the lack of space of the Kanonenjagdpanzer 1-3. Both could be solved by rearranging the design and by scaling the vehicle up. All in all, the Kanonenjagdpanzer 1-3 itself was a failure, but in the grand scheme of the Kanonenjagdpanzer, it was a step in the right direction.
Federative Republic of Brazil (1989-1991)
Main Battle Tank – 1 Built
Already from the start of the Tamoyo project for the Brazilian Army, there were requirements for a new tank which was to be armed with a 105 mm or 120 mm gun. As the Tamoyo project progressed, a split seemed to form, as the Brazilian Army was not in the position to buy a more advanced tank with a 105 mm. As such, the project seems to have split with the 90 mm armed Tamoyo 1 and 2 meant for the Brazilian Army, and the 105 mm armed Tamoyo 3 meant for export.
Whereas the Tamoyo 1 and 2 could still be seen as much improved M41 Walker Bulldogs, even though they were new and independent designs, the Tamoyo 3 was a significantly more serious project than a mere M41 redesign, and could compete with the tanks on the South American continent and with tanks of a similar weight class. The Tamoyo 3 was the apex of the Tamoyo program, being a true main battle tank in South America, and arguably a much better vehicle for Brazil than its EE-T1 counterpart.
The Tamoyo 3 came from a program that was designed for Brazil first and export second, while the EE-T1 was built for Saudi Arabia first and Brazil second or even more as an afterthought. Sadly, due to financial issues in Brazil and some opposition from the Brazilian Army, Brazil would lose its opportunity to acquire the most realistic Brazilian-designed main battle tank and effectively shut down any possibility of a future locally designed main battle tank for decades to come, dooming Bernardini at the same time.
Designations
The Tamoyo had various designations to denote the stages of the project. The first stage of the Tamoyo was designated X-30, with the ‘X’ standing for prototype and the ‘30’ for its 30 tonnes weight. This designation was used until the first working prototype of the Tamoyo 1 was delivered in May 1984.
After the initial mock-up stage, the vehicle received a new designation: the MB-3 Tamoyo, named to honor the Tamoyo Confederation of the Tupinambá people. The Tamoyo Confederation was an alliance of various indigenous tribes of Brazil formed in response to the slavery and murder inflicted on the Tupinambá tribes by the Portuguese discoverers and colonizers. The Tupinambá people fought against the Portuguese from 1554 to 1575. A peace treaty between the two warring parties was signed in 1563, although the fighting did not completely end until 1567 after the Portuguese colonists were sufficiently strengthened to tip the scales in completely in their favor. The Tamoyo Confederation was effectively wiped out by 1575. Tamoyo means grandfather or ancestor in the Tupi language.
The MB-3 Tamoyo has 3 main sub-designations: Tamoyo I, Tamoyo II, and Tamoyo III (named Tamoyo 1, 2, and 3 in this article for ease of reading). The Tamoyo 1 refers to the Tamoyo meant for the Brazilian Army, armed with a 90 mm BR3 gun, DSI-14 500 hp engine, and a CD-500 transmission. The Tamoyo 2 was exactly the same as the Tamoyo 1, except that it used a modern HMPT-500 transmission. The Tamoyo 3 refers to the upgraded export version armed with a 105 mm L7, with an 8V-92TA 736 hp engine, a CD-850 transmission, and armored with composite armor instead of only steel. The Tamoyo 3 would eventually be proposed to the Brazilian Army as well in 1991, a year after the failure of the EE-T1 Osório.
The Tamoyo 2 would receive an additional designation in 1987. At some point, the Tamoyo 2 received the 105 mm turret of the then unfinished Tamoyo 3 for a military exposition. The sign next to the Tamoyo 2 called the vehicle the Tamoyo-II-105. In this article, it will be called Tamoyo 2-105 for ease of reading.
The 8 envisioned vehicles and the first prototype received individual designations as well. These designations went from P0 to P8 and had sub-designations regarding their models as well. The first working prototype was designated P0 and held the model designation TI-1, where ‘TI’ refers to Tamoyo 1 and the ‘1’ refers to the first Tamoyo 1 vehicle. There were also three support vehicles envisioned: bulldozer, bridgelayer, and engineering vehicle. These are denoted by VBE (Viatura Blindada Especial, English: Special Armored Vehicle)
Prototype
Model designation
P0
TI-1
P1
TI-2
P2
TII
P3
TI-3
P4
TIII
P5
TI-4
P6
VBE Bulldozer
P7
VBE Bridge Layer
P8
VBE Engineering
Origin
The Tamoyo 3 program finds its roots from the previously developed 90 mm armed Tamoyo 1 and Tamoyo 2 projects meant for the Brazilian Army. At the time of these two projects, around 1984, the Brazilian Army sought a tank to counter the Argentinian TAMs, but at an affordable price as well. Initially, the concepts and requirements for the Tamoyo would have been quite similar to the Tamoyo 3 designed for export in 1987, but a lack of budget would temper these requirements into a more humble, albeit still capable vehicle.
The initial requirements laid out by the CTEx for the Tamoyo program were: a tank that weighed 30 tonnes (33 US tons, although this later seems to have increased to 36 tonnes (39.7 US tons) and was 3.2 meters (10.5 feet) wide for rail transport (same width as the Leopard 1), an operational range of around 500 km (310 miles), a ground pressure of roughly 0.7 kg/cm2 (10 lbs/in2), as high a percentage of locally-produced components as possible, and as much commonality of parts as possible with the M41 and the Charrua for logistical reasons. The Charrua was a locally designed tracked troop transport that was meant to replace the M113.
In addition, the vehicle had to use a conventional layout, with a 3 crew turret (there was no interest in autoloading systems). The national vehicle was to be armed with a 105 mm gun, while the export vehicle was to be armed with a 120 mm gun (that would become the Tamoyo 3), a stabilized gun, day/night sights, armor that should provide a high level of protection, diesel engines which gave the vehicles good power to weight ratios, and a fire extinguishing system.
Eventually, the requirements seem to have been reduced to a tank weighing 30 to 36 tonnes, 3.2 meters wide, an operational range of more than 500 km, a ground pressure of around 0.7 kg/cm2, parts commonality only with the M41 Walker Bulldog, and a national vehicle with a 90 mm gun. Overall, this was a more realistic vehicle for the Army’s budget, but their wish for parts-commonality with the M41 would eventually doom the Tamoyo 1 from its conception.
Bernardini recognized the disadvantages of the Tamoyo 1 and 2 tanks for the export market and decided to develop the Tamoyo 3 for export. In contrast to the Tamoyo 1 and 2 projects, where the Army seems to have provided a significant amount of funding, the Tamoyo 3 was Bernardini’s own endeavor and thus self-financed.
Concepts towards the Tamoyo 3
The development, or rather, the conception of the export Tamoyo seems to have run parallel to the Tamoyo development for the Army. Between 1979 and 1984, it seems that mainly the export Tamoyo concept designs were released, which were still designated X-30. The first of these was when the Tamoyo program resembled the Argentinian TAM. A sketch and explanation of the concept was presented in the newspaper O Estado de São Paulo on May 27th 1979.
The X-30 TAM
Division General Argus Moreira initially requested a tank with a front-mounted engine and rear turret, like the TAM. The tank and the project were designated X-30. An article in O Estado de São Paulo on May 27th, 1979 practically presented an improved copy of the TAM, although some of the combined requirements seem to have been somewhat unrealistic when one considers the TAM specifications. The new Brazilian X-30 tank was presented as a 30-tonne tank, armed with a 120 mm cannon, telemetric laser finder, a range of 600 km (370 miles), armor up to 70 mm (2.75 inch), NBC system, fire-extinguishing systems, 4 crewmembers, dual controls, and heat-treated armor angled at 20º to 50º. It was also supposed to be able to mount Brazilian copies of the Roland Surface-to-Air Missile system, although Brazil would never manage to successfully copy the SAM system.
To put these specifications in perspective, the TAM weighed 30.5 tonnes (33.6 US tons), had a 105 mm cannon, 590 km (366 miles) operational range, armor up to 50 mm (2 inch), a crew of four, and armor angled from 32º to 75º. The amount of road wheels of the X-30 is also exactly the same as on the TAM, suggesting more or less equal dimensions as well. The interesting part is that the X-30 effectively promised a better gun and better armor, while weighing as much as the TAM.
This presentation of the X-30 seems more of a propaganda article with the technician who gave the information to the journalist sketching a very impressive and capable vehicle that the Brazilian Army would most likely not have been able to afford in the first place.
The actual design of the X-30 TAM concept appears in an undated video of Bernardini where a shot briefly shows the design. The design resembles the sketch from the newspaper with some changes. The smoke dischargers are located on the front of the turret, there is no structure on the sides of the turret for the commander and loader hatches, the vehicle has an extra structure on the top of the hull which can be seen by the lower placed driver sights, and the vehicle has 3 return rollers instead of 4. The armament shown in the design of Bernardini is unknown. The sketch does not yet take the engine placement into account, although this might have to do with the drawing not being finished. The construction of a steel mock-up that used the front-engine configuration was already underway, but would never be finalized. The TAM-inspired design was very short-lived, as Bernardini and the CTEx opted for a traditional layout in less than 6 months.
The Traditional Layout X-30
The front-mounted engine design was discussed with Bernardini, considering weight balancing, armor distribution, and the moments of forces and inertia. In the end, Bernardini and the Army decided to go for a traditional layout with a rear-mounted engine. A contract between the Army and Bernardini was signed and the development of a mock-up and prototype was initiated. The switch to the traditional design happened at some point between May 1979 and January 1980.
A concept sketch of the traditional X-30 was presented in the first issue of Jane’s 1980 International Defence Review. A description of the concept was given as well, stating that the drawing shows Bernardini’s project for a 30 tonnes medium tank, designated X-30, which was currently in the definition phase. It would have a Diesel engine of 520 to 745 kW (700 to 1,000 hp), an automatic transmission, have a range of 500 km (310 miles), and a ground pressure of about 0.7 kg/cm2 (10 lbs/in2). The last two specifications were based on the Brazilian Army’s requirements. According to the Brazilian correspondent, it was to be armed with either a 105 mm or 120 mm gun, although the current concept showed a Cockerill 90 mm gun. In addition, it was stated that the first prototype was estimated to be ready for trials in two years.
This concept is estimated to be the first concept for two reasons. The first is the date when this concept was released, January 1980, which means that this concept was made about 6 months after the first TAM-inspired concept. The second reason is that this concept is nothing more than a mash-up of two tanks previously designed by Bernardini.
Jane’s concept mixes an enlarged X1A2 turret with the hull of an M41B. The concept derives in two major ways from the two vehicles it is based on. The first is that the hull is longer, as it has 6 road wheels instead of 5 on the M41, and the second is that the main gun looks like a lengthened EC-90 gun of the X1A2 with an added bore evacuator. Another difference is the driver’s hatch, which does not correspond with either vehicle.
It seems that this concept was already based on the specifications of the export version of the Tamoyo, which was the Tamoyo 3. There are a few interesting statements though. The first is the engine power, which is denominated in kW instead of hp. This was probably some kind of mix-up between units, as 520-745 kW translates to 700-1,000 hp, considering the given specifications are very close to the horsepower values which Bernardini presented for the DSI-14 and 8V-92TA engines.
Overall, this concept seems to mainly suggest a potential export version of the X-30 instead of the X-30 for the Brazilian Army. This concept is potentially one of the first drawings of the X-30 in a traditional layout. The design itself is somewhat unimaginative, considering it is a mash-up of the X1A2 and the M41B, and the specifications are somewhat questionable as well.
An Artistic Interpretation
This concept was released in the press and abroad after the switch to the traditional layout. This concept dates back to at least April 1980, as the sketch is shown on the cover of the book Brasil Defesa – Os Blindados do Brasil. In this sketch, the X1A2 turret is a little bit altered, but uses a redesigned hull that resembles the final hull design much closer.
This concept retains a redesigned variant of the X1A2 turret, but the hull in this concept is different. The hull shares much fewer design features with the original M41 or the Brazilian M41B and M41C. The engine deck looks more like a main battle tank and resembles the Tamoyos which were built. The tracks of the concept do show a very clear resemblance with the M41 tracks. The gun on this concept is unknown, but it does seem to resemble a 105 mm gun, although this is pure speculation.
Initial Component Selection
With the main development of the Tamoyo 1 and Tamoyo 2 completed by 1986, Bernardini set out to develop their export vehicle. To develop the new vehicle, Bernardini looked towards the United States for inspiration, which was developing vehicles of a similar concept.
In the early 1980s, the United States started looking for a new light tank to replace the M551 Sheridan. This program was known as the XM-4, for which the Commando Stingray, Teledyne Continental Motors ASP, Food Machinery and Chemical Corporation CCVL, the Swedish IKV-91, and the later Food Machinery and Chemical Corporation Armored Gun System (later known as the M8) were proposed. A range of components used for the XM-4 tanks can be found in the Brazilian Tamoyo as well.
The Bernardini Engineers were most likely inspired by the XM4 tanks, as they were said to have been present during trials and followed the project’s developments. It is hard to not notice the similarities between some of the XM4 specifications of the Stingray and the XM8 and the eventual Tamoyo 3 (the final stage of the Tamoyo program, which was initially designed with export in mind). Both programs would use a low recoil force 105 mm gun, a Detroit Diesel 8V-92TA engine, an HMPT-500-3 transmission, had the same speed, the same operational range, and the same ground pressure.
The first influences of the XM-4 program can be seen in the Tamoyo 2, which was, for all intents and purposes, a Tamoyo 1, but with a modern HMPT-500-3 transmission instead of the old CD-500 transmission. The HMPT-500-3 transmission would also find its way into the Tamoyo 3 program as an optional component for Bernardini’s potential customers.
Bernardini decided to go for the Detroit Diesel 8V-92TA 736 hp engine and combine it with the CD-850-6A or HMPT-500-3 transmissions. The Detroit was said to have been able to receive an uprating towards 900 hp in the future, giving a potential hp to ton ratio of 29 instead of 23.75 (23 kW/t instead of 17.7 kW/t), but this was never implemented. The CD-850-6A was selected when General Motors was shutting down the CD-850 production, which would make obtaining licenses more viable for Bernardini. In addition, due to the extensive usage of the CD-850 in armored vehicle development, there was still a large market requiring spare parts for at least a couple of years. The CD-850 was effectively the flagship transmission of the Tamoyo 3 program.
Bernardini realized the inadequacy of the 90 mm F4 gun on the export market, and opted to arm the Tamoyo 3 with a 105 mm gun instead. Bernardini selected the Royal Ordnance 105 mm L7 LRF (Low Recoil Force) gun as the main armament of the export version. This gun finished development in late 1983 and could be mounted on vehicles such as the M41 Walker Bulldog, the Stingray, M47 Patton, and T-55s.
As the previously mentioned vehicles suggest, the 105 mm L7 LRF could be mounted on vehicles weighing around 20 tonnes. This was done by installing a muzzle brake, designed to allow the firing of APFSDS rounds (Armor Piercing Fin Stabilized Discarding Sabot) without damaging the sabot, and by facilitating a larger recoil stroke for the gun. This meant that, when the gun was fired, it recoiled up to 762 mm instead of the original 290 mm. The increased recoil length would have a few downsides, as the gun took up more space due to the recoil and the recoil could cause certain lighter and less wide vehicles to tip over when firing perpendicular to the hull and on a slope, as the center of mass would also shift. The last issue was not a problem for the Tamoyo 3 and it would not use a muzzle brake either.
The Tamoyo 3 Starts to Take Shape
With the main components of the Tamoyo 3 selected, the design of the tank could begin. The base hull design and suspension remained effectively the same with the Tamoyo 1, but from there, the vehicle got increasingly more advanced. The hull was to ber armored with spaced armor and the turret with composite armor, the 105 mm gun required a modern fire control system, modern fire prevention systems, NBC system, decreased thermal signature, and improved mobility.
Since the step from building effectively modernized post-World War 2 designs to designs that resemble 1970s technology is quite large, Bernardini hired two Israelis to consult them in new design concepts.
Israeli Influence
Bernadini visited Israel a number of times for consultation by General Israel ‘Talik’’ Tal, the mastermind of the Merkava tank. In addition, Bernardini also hired General Natke Nir (sometimes referred to as Natan Nir), who served as a colonel during the Yom Kippur War, for 6 months as a consultant for the design of armored vehicles. Natke Nir is credited by Flavio Bernardini for introducing spaced and composite armor concepts, improved protection against explosions, ammunition compartmentalization, mine protection, and the employment of tanks in combat situations. Although these consultancies were mainly focused on the Tamoyo 3, it would not be surprising if some concepts were or would eventually be carried over to the Tamoyo 1 as well.
Overall, it seems that the role of General Natke Nir was mainly to introduce Bernardini in what were the design standards of the day, and to tell them which designs would work and which would not based on his own experience. A practical solution that was suggested by Natke Nir was the addition of a number of small plates welded to the side of gunner periscope depression. The plates were meant to prevent machine gun fire from bouncing into the gunner’s periscope.
Gathering Components
Besides somewhat lacking the know-how of modern tank building, Bernardini and Brazil as a whole also lacked local Brazilian companies able to provide such high-grade components. Like Engesa before it, Bernardini started partnerships with a number of companies to gather the needed components to build their Main Battle Tank.
Among these companies were American, British, Brazilian, and German companies. The Americans would supply Bernardini with the transmissions, engine, and sights. It is unclear if Bernardini ever acquired the license to produce the CD-850-6A transmission or if this was to be done when they managed to sell the vehicle. The British provided the gun, the computers for the fire control system, and fire safety equipment. Bernardini and other Brazilian companies would mainly work on the steel, construction, and the suspension of the vehicle, while the German companies delivered most of the remaining components of the fire control system.
Country
Company
Component(s)
Brazil
Bernardini
Hull, turret, suspension components, composite armor, electric turret, and elevation drives
Brazil
Themag Engenharia
Electric turret and elevation drives
Brazil
Universidade de São Paulo
Electric turret and elevation drives
Brazil
Eletrometal
Torsion bars
Brazil
Usiminas
Steel
Brazil
Novatracão
Tracks and suspension components
Brazil
D.F. Vasconcellos
Driver’s day sights and potentially all other day sights (unknown if they supplied the driver’s night vision sight)
Germany-Brazil
Moog-AEG-Siemens do Brasil
Stabilization and elevation systems
United Kingdom-Brazil
Ferranti Computers do Brasil
Computers and programming for the fire control system
France
Unknown
Switches and connectors
United Kingdom
Royal Ordnance Nottingham
105 mm L7A3 Low Recoil Force
United Kingdom
Graviner
Turret fire protection system (potentially the entire system including the engine bay as well)
United Kingdom
Rank Pullin (General Electric Company UK in 1988)
Optional supplier of periscopes and laser range finder (potentially telescopes)
United Kingdom
Lucas Aerospace
Generator and regulator
United States
Unknown
Turret slewing bearing and telescopes (telescope potentially from Kollmorgen)
United States
General Electric Company US
HMPT-500-3 transmission (optional)
United States
General Motors Allison
CD-850-6A transmission
United States
General Motors Detroit
8V-92TA 736 hp Diesel Engine
United States
Kollmorgen Corporation
Installed periscopes and laser range finder (potentially telescopes)
Unknown
Expectronics
Unknown
It is important to note, like the EE-18 Sucuri and most likely the EE-T1 Osório, that a significant number of these components were on loan. Loaning components was done to save development costs while attempting to sell the vehicle. The loaned components were the Ferranti fire control system computer, turret stabilization, slewing and elevation system from Moog-Aeg Siemens, components from Detroit Diesel Alison, the generator and regulator from Lucas Aerospace, the sights from Kollmorgen, and supposedly the Rank Pullin sights. Of these, the Ferranti computer was to be returned on November 21st 1991.
Composite Armor Development
A big step in the development of the Tamoyo program was the integration of composite and spaced armor in the design of the Tamoyo 3. An interesting fact is that the Tamoyo 3 is in fact the only vehicle of the two Brazilian Main Battle Tanks to integrate composite armor. Although the Osório was planned to mount composite armor, a number of sources state that it never received a composite armor pack. The author tested the cavities of the 120 mm armed Osório in Santa Maria which sounded hollow. The third prototype, known as the EE-T1 P3, which was meant to be the production vehicle prototype for Saudi Arabia, was planned to have composite armor installed, but the vehicle was never finished due to Saudi Arabia buying the Abrams and Engesa’s subsequent bankruptcy.
The Bernardini technicians went to the United Kingdom, France, Germany and Israel to gain more knowledge on composite armor, among other things. The eventual composition resulted from extensive testing at Marambaia Proving Ground and in Bernardini’s laboratories. The eventual Tamoyo 3 used a mix of composite and spaced armor, with the exact locations of these two types being unknown, with both types potentially integrated at the same places.
The armor is very generally described in the brochure as a frontal armor which puts special emphasis on the use of high quality alumina and boron ceramics, special resins, carbon fibers and non-ferrous materials which were enclosed by high hardness steel plates to offer protection against large caliber shaped charges. According to Flavio Bernardini, they started developing a composite armor after they visited Israel. He claims the armor made use of spaced steel, high purity aluminium oxides like AL2O3, and used inox steel pins bonded in plastics and rubber. Based on this description, the Tamoyo 3 was likely to have incorporated some form of lamination style composite. Based on the dimensions of the cavities, a NERA style package seems fairly unfeasible.
The base steel hull of the Tamoyo vehicles was meant to protect it frontally from 30 mm autocannon fire and 14.7 AP from at least the sides. According to Flavio Bernardini, they never truly finished the composite design, but Bernardini attempted to make the Tamoyo 3 composite sections protect against RPGs and 90 mm HEAT ammunition from, for example, the Cascavel. Based on the dimensions however, it seems that the Tamoyo 3 in its current form would barely be able to protect against such projectiles reliably.
The reconstructions of the Tamoyo 3 armor were only possible because the author could measure up the vehicle himself at the Carlos Combat Cars Tank Museum. As such, the author is the first to publish the structure and corresponding thickness values of the Tamoyo 3 tank.
The hull design differed significantly from the Tamoyo 1. While the Tamoyo 1 followed a fairly traditional design style of a single plate, the Tamoyo 3 used multiple plates to form a cavity. The exterior lower and middle plates were 55 mm thick steel plates, while the upper front plate was heavily angled and 27 mm thick. A backing plate, attached to the lower front plate and the upper front plate, was used to create the cavity. It is unclear if the backing plate was either 27 or 55 mm thick as Bernardini double stacked plates, which made ultrasonic measuring problematic.
It is unclear if the hull cavity was ever filled with armor. There is an access hatch to the cavity, but this has never been opened by the current owner. This access hatch could mean that the cavity could be filled with a thin composite package of 100 mm thick or with for example a fuel tank, or just act as spaced armor. The total estimated Line of Sight thickness of the hull could reach about 500 mm at best based on the rough dimensions achieved by measuring up the steel plates and by finding the corresponding angles.
The turret was, while not the final design, a fairly sensibly designed turret for the integration of composite. The Leopard 2 style turret design would have allowed for fairly easy integration of composites due to the simple straight shapes. The turret would have likely used a mixture of composite and spaced armor, with composite located in the gun shield and the turret cheeks, and the side plates using spaced armor. The author attempted to determine if the cavities were filled, but due to the thickness of the steel plates, it was difficult to reliably determine if the cavities were filled. The gun shield thickness could also not be determined reliably.
During the initial phases of development, Bernardini also considered explosive reactive armor, but discarded it, as the base steel hull plate was too thin. The engineers also considered placing fuel tanks in advantageous positions to act as armor and also studied the use of kevlar in plastics against fragmentation.
Tamoyo 3 is Built and Presented
When the construction of the Tamoyo 3 prototype began is unknown. It is said that construction began somewhere after the Tamoyo 2 was completed, which was in 1986. The turret was the first to be completed, as the Tamoyo 2 hull with the Tamoyo 3 turret, known as the Tamoyo 2-105, was presented at a military exhibition sometime before May 10th 1987.
On May 10th, 1987, the Tamoyo 2-105 was presented at the Cavalry Festival in Rio Grande do Sul. The vehicle was shown to the Army Minister at the time, Leônidas Pires Gonçalves (1985-1990), and the commander of the Comando Militar do Sul (Southern Military Region), General de Exército (equivalent to a four-star General) Edison Boscacci Guedes, by Flávio Bernardini. At some point the turret was removed from the Tamoyo 2-105, and remounted on the Tamoyo 3.
Considering the author found manufacture plates stamped with 1989, it would have been very likely that the Tamoyo 3 prototype was completed in 1989. What is remarkable, however, is that the Tamoyo 3 was never tested outside of Brazil, even though it was an export vehicle. The fact that Tamoyo 3 was only finished in 1989, meant that it missed the chance to perform during the 1988-1989 Ecuador trials. The TAM is said to have won these trials by a landslide, scoring 950 out of a 1,000 points, but, as so frequently with South American countries, the tests did not result in any acquisition.
The Tamoyo 3 in Detail
The Tamoyo 3 weighed 31 tonnes unstowed and 35 tonnes combat loaded. The vehicle was 8.9 meters (29.2 feet) long including the gun, 3.29 meters (10.8 feet) wide, 2.35 meters (7.7 feet) tall up to the turret top, and 2.5 meters (8.2 feet) tall including the commander’s machine gun. The hull of the Tamoyo 3 was 6.48 meters (21.25 feet) long and was operated by a crew of four. This crew consisted of the commander (right side of the turret in the middle), gunner (in front of the commander), loader (left side of the turret in the middle), and the driver (front left of the hull). The turret had two hatches, one for the commander and gunner and one for the loader.
Hull
The Tamoyo 3 was almost entirely constucted out of 27 mm thick plates, with thicker parts being created by double stacking the 27 mm plates to obtain 55 mm plates. It was quite likely that this was done considering the Tamoyo 3 was a prototype and it was simply cheaper. The hull was structured in such a way that a cavity was created. This cavity could be filled, but it is unknown if this was ever done. There was an access hatch to the front hull cavity, but the current owner has not openened the hatch at this point in time. Overal the Tamoyo 3 was fairly well protected for its weight class.
Tamoyo 3 Base Hull Armor
Location
Thickness
Angle from vertical
Effective thickness
Upper Front
27 mm (1 inch)
75º
105 mm (4.1 inch)
Middle Front
55 mm (2.2 inch)
45º
78 mm (3 inch)
Lower front
55 mm (2.2 inch)
60º
85 mm (3.3 inch)
Cavity
350 to 380 mm at best (14 to 15 inch at best)
–
350 to 380 mm at best (14 to 15 inch at best)
Front backing plate
27 to potentially 55 mm (1 to 2 inch)
45º
38 to 78 mm (1.5 to 3 inch)(
Sides
27 mm (1 inch)
0º
27 mm (1 inch)
Rear
27 mm
0º
27 mm (1 inch)
Top
20 mm (0.8 inch)
90º
20 mm (0.8 inch)
The Tamoyo 3 had a headlight on each side of the front hull, together with what seem to be black-out markers next to them. Both the spaced and the non-spaced armor vehicle offered mounting points for spare tracks on the upper front hull plate. The sapced armor Tamoyo 3 offered extra mounting points for tools and also two stowage bins that extended from the front hull top towards the fenders at the same angle as the spaced armor plate. Two rear view mirrors were installed, each on a fender. The Tamoyo 3 with spaced armor also offered two fire extinguishers on the bottoms of the stowage bins, and a siren on the right side of the upper front hull plate. The driver’s hatch was located on the front left and had 3 sights, of which the center sight could be replaced with a night vision sight. In an interior picture, the left sight is seen to have been made by D.F. Vasconcellos, but it is unknown if the center night vision sight was also from D.F. Vasconcellos.
The driver’s hatch incorporated a sight while two other sights were installed on this raised construction. The hatch was a rotating one on both vehicles and the driver also had access to a hull escape hatch on the tank floor, located under the driver’s seat. The driver’s seat was adjustable in both height and distance and could be folded over to reach the escape hatch.
The driver used an adjustable steering wheel to steer the vehicle and could select the gear in neutral, pivot neutral, low, high, and reverse. The accelerator pedal was located on the right side and the brake pedal on the left side. The Tamoyo 3 also featured a hand throttle for independent acceleration of the accelerator pedal. A fuel tank selector was located on the right side of the driver, which allowed for the selection of fuel tanks. A total of 24 rounds of 105 mm ammunition were stowed to the right of the driver.
The gun travel lock was located on the top rear side of the hull in the middle. The rear of the Tamoyo 3 had a rear light and a black-out light on either side and also an infantry phone box located on the right rear, under the rear lights. In addition to the towing hook, two brackets were installed on this plate and on the lower front plate as well.
The hull side provided mounting points for the installation of side skirts, which consisted of 4 sets of skirts on each side. The early versions of the side skirts were made from steel, but would later incorporate materials like rubber and aramid fibers to improve the effectiveness against certain projectiles.
Mobility
The Tamoyo 3 was powered by the Detroit Diesel 8V92TA water-cooled diesel engine in a separate compartment. This engine produced 736 hp at 2,300 rpm and 2,615 Nm torque at 1,500 rpm, which gave the vehicle a power-to-weight ratio of 23.7 hp/ton empty and 21 hp/ton combat-loaded. It used a General Motors CD-850-6A transmission which had 2 forward and 1 reverse gears. The low gear had a gear ratio of 3.50:1, the high gear had a ratio of 1.26:1, and the reverse had a ratio of 4.90:1. The General Electric HMPT-500-3 transmission was offered as an alternative. The 8V92TA and CD-850 powerpack gave the Tamoyo 3 a top speed of 65 km/h (40 m/h) and could be removed in less than 40 minutes. It had a fuel capacity of 700 liters (185 gallons), with 300 liters (80 gallons) each for the fuel tanks on the left and the right side of the tank, and 100 liters (26.4 gallons) for the frontal tank. The tank had an operational range of about 500 km (310.7 miles) with a fuel consumption of about 0.75 km per liter (1.76 miles per gallon).
The Tamoyo 3 used a torsion bar suspension with 6 road wheels and 3 return rollers on each side. The tank had a drive sprocket on the rear side, which likely shared the same dimensions as that of the M41, as it used the same tracks and had the same amount of teeth. It also had an idler wheel on the front. It had 3 additional shock absorbers installed, with 2 mounted on the front two road wheels, and 1 on the last road wheel. The torsion bars were previously developed by Eletrometal and Bernardini for the M41B program. These torsion bars were made from 300M alloy steel, which was also used for the torsion bars of the M1 Abrams. The idler wheel was mounted on the front side of the vehicle, while the drive sprockets were installed in the rear.
The Tamoyo 3 used Brazilian copies of the T19E3 tracks produced by Novatraçao. The suspension was protected by a side skirt. The T19E3 tracks had a width of 530 mm (20.8 inch), and a ground contact length of 4.51 meters (14.8 feet). This gave the Tamoyo a ground pressure of 0.74 kg/cm2 (10 lbs/in2) and a trench crossing ability of 2.4 meters (7.9 feet). The tank had a ground clearance of 0.5 meters (1.6 feet) and could climb a 0.71 meters (2.3 feet) tall vertical slope. It could climb a slope of 31º, and be operated on a side slope of about 17ºs. The vehicle had a fording capability of 1.2 meters (4 feet) and could neutral steer as well.
The engine allowed operation up to 51º Celsius without limiting the vehicle’s engine performance. The exhaust could have been mounted externally if requested, but would normally come out of the rear grills where it was used with cooling air to reduce the thermal signature. To better facilitate wading, an engine air intake could be used, passing through the turret or externally. A bilge pump was used to pump away any excess water.
Turret
The Tamoyo 3 supposedly made use of composite and spaced armor. The author was unable to determine if the cavities were hollow or not, but if composite was integrated, this would have likely been done at the front of the turret. The turret cheeks were protected with a 55+50+55 (steel+cavity+steel) layout which was angled at 45º and tapered upwards at around 10º, giving a relative thickness of about 235 mm if the cavity was filled with a laminate composite package. This would barely be able to make the Tamoyo -3 protect against 90 mm HEAT ammunition from the EE-9 Cascavel depending on how effective the laminate would be.
It was not possible to reliably measure up the gun shield armor, but it would have been likely if this was either 235 mm thick atleast to match the Line of Sight value of the cheeks, up to 300 mm thick which appears in sourcing. The sides were armored with a 27+50+27 layout angled at about 10º, with the cavity likely to have been empty for the sides to act as spaced armor to save weight. The rear sides and rear were armored with 27 mm thick plates. The turret top including the blow-out panel was protected by 20 mm thick steel, while the removeable top plate to pull out the 105 mm gun was protected by about 13 mm.
The Tamoyo 3 had a turret ring of 2 m (6.6 feet), which was the same as the Tamoyo 1 and 2. The turret had 2 hatches, one for the commander and gunner, and one for the loader, which were located on the turret top on either side. The commander was located on the middle right of the turret, with the gunner in front of him, while the loader was located on the middle left of the turret.
The gunner had access to a periscope, which was located on the front right of the turret, and an emergency coaxial telescope for the 105 mm gun. The commander had access to 7 periscopes, of which at least one was the same as the gunner’s periscope for independent target acquisition. The loader also had access to a periscope.
External features of the Tamoyo 3 turret included a bolted-on turret top plate to facilitate the removal of the gun. On the front left, there seems to have been a cover for a potential mounting point of a meteorological station to measure temperature, wind speed and direction. The loader’s periscope was located behind the meteorological station, in front of the loader’s hatch. The gunner’s periscope was located on the front right in a dedicated depression of the turret.
The commander’s station was located behind the gunner’s periscope and offered a rollable rail-mounting point for a machine gun. An unknown component was located between the loader and commander’s hatches. This might be an additional mounting point for a machine gun. The antenna’s were located behind the loader’s hatch to the left side and all the way to the rear right. A visible blow-out panel is seen on the rear left as well, with the ventilation and NBC (Nuclear, Biological, Chemical) system ventilation cover in the middle rear of the turret. A large stowage bin was mounted on the rear as well.
The turret had a number of lifting hooks spread out over the front and sides (6 in total) and also offered 3 handles to enable the crew to climb on the turret. A set of 4 smoke dischargers was installed on each side of the turret rear.
The coaxial machine gun was located on the left side of the 105 mm gun and could be fired by the gunner and commander stations and manually by the loader. The loader had access to 6 boxes of 7.62 mm ammunition in a stowage to the left, mounted on the top plate. An additional 10 boxes of 7.62 mm or .50 ammunition were stored on what seems to be on the floor of the turret basket, resulting in a total of 4,000 rounds of 7.62 mm ammunition.
The Tamoyo 3 had two types of ammunition stowage for the 105 mm gun. It had a rear stowage located in a blast-proof compartment, with an access door on the left rear of the turret and a blow-out panel on the top, which offered room for 12 rounds. The other type was a 6 round ready-to-use vertical stowage location on the turret basket. These stowages were open and did not protect the crew in case of an ammunition ‘cook-off’.
Most of the control panels and fire control system computers and panels were located at both the gunner and commander’s stations. The outer turret basket and the area around the recoiling gun were covered as much as possible with steel mesh to prevent the turret monster from claiming its fair share of tribute from the crew.
Armament
The Tamoyo 3 was armed with a Royal Ordnance 105 mm L7 LRF (Low Recoil Force) gun packed in a thermal sleeve (the thermal sleeve was not mounted when it was presented in 1987). This gun was developed after late 1982 and would arm the Cadillac Gage Stingray, among others. By mid-1984, two prototypes were completed. The gun used a longer recoil stroke and could also use a muzzle brake to lessen the recoil forces of the gun. The Tamoyo 3 would not use the muzzle brake. These low recoil guns could be mounted on light vehicles such as the M41, but also on the T-55 and M47 Patton.
The gun had an overall length of 6.8 meters and had a recoil stroke of 762 mm. It weighed 1,932 kg and had a recoil pull on the trunnions of 113.75 kN. The 105 mm cannon could fire every round developed for the L7, which makes it a bit challenging to determine which rounds would be used on the vehicle. This would vary from customer to customer, so the decision was made to use the ammunition presented in the source material and the 105 mm ammunition used by the Brazilian Army today.
Tamoyo 3 Ammunition
Round
Capability
Effective range
Velocity
Weight
L64 APFSDS (armor piercing fin stabilized discarding sabot)
170 mm at 60º from vertical at 2,000 meters.
2,500 meters
(2734 yards)
1,490 m/s
3.59 kg dart (Tungsten, 28 mm diameter)
APDS L52 (Armor Piercing Discarding Sabot)*
240 mm flat from vertical at 2,000 meters.
210 mm at 30º from vertical at 2,000 meters.
120 mm at 60º from vertical at 2,000 meters.
2,500 meters
(2,734 yards)
1,426 m/s
4.65 kg sub-projectile/6.48 kg projectile
HEAT M456 (High Explosive Anti Tank)
360 mm (13.8 inch) at 30º at any range.
2,500 meters (2734 yards)
1,174 m/s
10.25 kg (8 lbs) projectile
L35 HESH (High Explosive Squash Head)*
A multipurpose round for both anti-armor and anti-personnel purposes. Also used as High Explosive.
–
732 m/s
11.26 kg (11.6 lbs) projectile
White Phosphorus – Smoke
Smoke round
–
260 m/s
19.6 kg (11.9 lbs)
* Those with an asterisk denote the ones used by the Brazilian Army
The turret had an electric elevation and traverse system and offered a gun elevation of 15º and a gun depression of -6º. It had a maximum elevation speed of 266 mils/s or about 15º per second and a maximum traverse speed of 622 mils/s per about 35º per second. It was further armed with a coaxial and turret top 7.62 FN MAG machine gun, although the coaxial machine gun could be replaced with a .50 as an option. The Tamoyo 3 stored 42 rounds of 105 mm ammunition and at least 4,000 rounds of 7.62 ammunition. A searchlight was installed coaxial to the gun.
Fire Control System
The Fire Control System (FCS) is one of the main components which set the Tamoyo 3 apart from its predecessors when it comes to how modern the vehicle was. However, it is somewhat hard to determine how good the fire control system actually was, as a Bernardini transcript mentions that the option of fire on the move was still to be implemented. It is not clear if this option was ever finalized by the end of the project. Most of the data presented here comes from the description of this transcript and a table on the FCS system which appear in the book Bernardini MB-3 Tamoyo by Expedito Carlos Stephani Bastos and from Ed Francis from Armoured Archives.
The Tamoyo 3 used a Ferranti Falcon computer system as the brains of the FCS and used Kollmorgen sights and Moog-AEG components for its stabilization. The Ferranti Falcon FCS was considered in the British Chimera project in 1984 alongside the Marconi IFCS (used on the later Chieftains and the Challenger 1), DFCS, AFCS SFCS 600, EFCS 600, MFCS and the Belgian OIP LRS5. What is interesting is that the Ferranti Falcon was the cheapest of the FCS systems coming in at £25,000, apart from the MFCS which was based on the EFCS 600 and cost £15,000. Interestingly, the calculation error of the Ferranti Falcon was 0.2 mils (so +- 0.2 meters inaccuracy per kilometer) while the MFCS had an error of 0.1 mils. So not only was the Ferranti Falcon worse than the cheapest option of Marconi, it was also more expensive.
The base version of the Tamoyo 3 used second-generation image intensifier tubes for both the Commander and Gunner as day-night vision for their main periscopes. Depending on the need, the image intensifier could be upgraded to a third-generation providing a more sensitive tube due to the application of gallium-arsenide in the photocathode, enabling the sight to operate at much larger distances. Second-generation image intensifiers were first developed in the late-1960s, while the third-generation image intensifiers were first developed in the mid-1970s and started entering production in the 1980s. On request, the sights could also be used with thermal imaging instead. The main difference is that image intensifier tubes need some light to function while thermal imaging does not.
The FCS periscopes used on the base Tamoyo 3 were M220 periscopes from Koolmorgen, which were also used on vehicles of the American XM4 light tank program at the time. On request, the periscope could use image intensifier tubes or thermal imaging. The vehicle was also offered with the M20 periscope with image intensifier tubes or any other periscope the customer might have wanted instead. The M220 periscopes gave the commander and gunner an amplification of 8 times for both day and night vision. The sights had an 8º and 7º field of view for day and night respectively and a lens diameter of 6 mm. The deviation of the parallel image on the sight display was 0.15 mils at maximum (10 km, meaning +-0.15 meter inaccuracy at 10 km).
The Ferranti Falcon FCS on the Tamoyo 3 worked between 400 and 9,995 m (437 to 10,930 yards) and was a 2-axis stabilized system. That the FCS only started working beyond 400 m is very strange and seems to have something to do with the Laser Range Finders (LRF) of the time in general, which in turn also mostly function between 400 and 9,995 meters. The LRF had an inaccuracy of 0.45 mils, which meant that, at a range of 2 km, the accuracy can be about +- 0.9 meters or +- 4.5 meters at 10 km. The receiver, however, had an inaccuracy of 0.56 mils, which would result in an inaccuracy of +- 5.6 meters at 10 km.
The table also gives a mils error value for when the Tamoyo 3 tried to fire on the move. Note that this function was supposedly not yet finished according to the transcript of Bernardini. It is thus unclear if this number is accurate for the actual end product. According to the table, the FCS had an error of 1 mils while firing on the move at a speed of 20 km/h (12.5 m/h). When this is compared to a table in Technology of Tanks by Richard Ogorkiewicz, this means that the Tamoyo 3 stabilization and FCS would have been equivalent to that of a basic stabilizer of the 1960s.
As previously stated, both the commander and gunner had the same sights and both could fire the gun. They could search for targets at the same time and lay and fire the gun. It is unclear if the commander could also program his target in the system so that the gun would automatically lay on target at the push of a button when he overrode the gunner. In case the periscopes could not be used, the gunner had access to a coaxial telescope with 7x magnification.
The FCS system took the following variables into account: weather, type of ammunition, temperature of ammunition, tilt of the gun, turret angle, gun firing, range. The Tamoyo 3 was fitted with a selector for 5 different types of ammunition, but could be expanded on request.
In the end, the effectiveness of the Tamoyo 3 FCS is somewhat uncertain. While standing still, it was a decent fire control system but had the interesting quirk of a not functioning LRF within 400 m, and firing on the move seems to have never been fully worked out. In the case firing on the move was properly implemented, it remains uncertain if it would still have had 1 mils of inaccuracy. In any case, based on the data available on the FCS, it was probably not a very good FCS during the 1980s and would have been more akin to FCS systems from the 1960s or 1970s.
Fire Protection System
One of the main systems marketed by Bernardini was its fire protection system. Although not much more special than what was in common use on other tanks of the time, it did represent one of the larger advancements for the company in crew safety, apart from the much-improved armor technology.
The fire protection system was designed and delivered by Graviner and offered 4 suppressors, of which 2 were installed in the engine bay and 2 in the turret. All 4 suppressors used HALON 1301 as extinguishing gas, which could be used in crew-operated spaces without risk to life. The suppressors in the engine bay contained 3 kg (6.6 pounds) of HALON, while the amount of the turret suppressors is unknown. The Tamoyo 3 would be sold with 2 external spare CO2 fire suppressors of 2 kg (4.4 pounds) each.
The engine bay was protected independently from the crew compartment, which was controlled by the driver. The system could be activated manually or automatically depending on the setting the driver used, with the manual activation being done through an emergency switch which was protected to prevent accidental activation. Detection was done through a system that monitored the capacitance and resistance between the wire and insulation through temperature increase. A drop in resistance and rise of capacitance of the insulation sent off a warning signal or automatically activated the system. The fire detectors formed a protective mesh around the powerpack to better protect the engine from fires.
The turret fire protection system consisted of a control panel, 2 suppressors, and 4 infrared detectors. The infrared detectors could quickly pick up significant rises in temperature and send a signal for the fire protection system to start suppressing the fire. The system could be used in 3 settings: peace, war, and off. In peace mode, 2 detectors had to signal the presence of a flame before sending a signal which would first initiate one of the suppressors and after 5 seconds it would initiate the second suppressor if needed. The system only needed one detector to activate in war mode to discharge both suppressors. The fire protection system could be tested when it was turned off from the electrical system. Both suppressors were located on the loader’s side.
Other Systems
Power to the electrics was provided by two 105 Amp 28 Volt Alternators next to the powerpack. These alternators could be accessed from the crew compartment through a special hatch. A single 500 Amp alternator could be chosen as an option. The Tamoyo carried 4 batteries connected in series-parallel to also provide power to the tank when the main engine was turned off, allowing the vehicle to still use the rest of its systems in a potentially limited capacity. To better protect against short-circuits, 2 main relays could be selected by the driver. As an optional component, 4 NATO standard TN-12-100 Batteries could be supplied. These are 12 volt batteries, each with 100 Ah, which could be interchanged with a large number of vehicles. The batteries could be accessed through the engine bay hull top hatch.
The Tamoyo 3’s radio system consisted of a KX16A power circuit breaker, an AK20 high-frequency distributor, a KO19 repeater box, a KO20 secondary controller for each crew member in the turret, two antennas on the turret top, and an AV-3 amplifier. The vehicle could receive any radio systems, such as the EB 11-204D, AN/PRC-84 GY, and AN/PRC-88 GY from any manufacturer. The radio was located in the turret rear and could be operated by both the commander and loader. The radio also included a mobile station for the crew to take with them when they had to exit the vehicle and intercoms for exchange of commands with the crew. The Tamoyo 3 also offered an external telephone on the rear of the vehicle for infantry and support units to communicate with the tank crew.
A number of other features were offered for the Tamoyo 3. These included a heater and an NBC system (Nuclear, Biological and Chemical filter). The heater would have been an independent system from the powerpack, although it is unknown how it would exactly have been implemented. The NBC system would include the addition of special seals on the hatches, turret ring and so on to seal the vehicle. The system would have a selector for the filter.
Engesa Enters the Fray
In 1982, Engesa broke the gentlemen’s agreement on which the Brazilian armored vehicle industry was founded. Engesa, which was supposed to focus exclusively on the development of wheeled armored vehicles, initiated the development of the EE-T1 Osório. Although the Osório was not directly developed for the Brazilian Army, Engesa still decided to use some of the initial requirements laid out by the Brazilian Army so that they could sell it to Brazil as well, but with a 105 mm gun instead. Engesa decided to increase the weight to make it more capable on the export market, but retain the 3.2 meter (10.5 feet) width.
The tank Engesa ended up with was a vehicle that outperformed the Tamoyo 1 in every aspect, except price. The Osório would outperform the later Tamoyo 3 as well in multiple aspects. In 1986, the Osório with 105 mm gun was trialed by the Brazilian Army. The Osório impressed the Brazilian Army so much that they practically seemed to have forgotten about their initial requirements of interchangeability. The Brazilian Government supposedly promised Engesa that they would buy 70 Osórios, but this would later increase to 150 or 300 Osórios according to sources. This decision effectively meant that the Army forwent the Tamoyo project which they had initiated, which was tailor-made to Brazilian requirements, and decided to go with the Osório.
The Overall Tamoyo Program and the Army
The fate of the Tamoyo 3 is somewhat tied to the earlier Tamoyo 1 and the appearance of the Osório. The now finished prototypes of the Tamoyo 1 were trialed by the Brazilian Army in 1988. Considering various Tamoyos, like the Tamoyo 2 and 3, were already finished around 1986-1987, this date seems to be quite late. Flavio Bernardini noted in one of his memoirs that the Tamoyo program was ‘’Empurrada com a barriga” (Eng: Put under the belly) by the Army, which is a saying suggesting that the Army seems to have somewhat deliberately postponed the trials.
The second Tamoyo 1 (TI-2) was trialed by the Army in 1988, and subsequently rejected. The TI-2 was not fast enough and its acceleration was lacking as well. In addition, the oil filter was damaged and the gearbox was damaged due to cracking near the fixation points of the spur gears.
This rejection presented a few major issues. The first was that neither the Tamoyo 1 nor the Tamoyo 2 could match the new requirements by the Army in their current configuration. Bernardini considered converting the Tamoyo 1 (TI-3) to a potential Tamoyo IV (4) version. The Tamoyo 4 would have used an MWM engine and ZF gearbox for its powerpack. This was viable since both MWM and ZF had sizable subsidiaries in Brazil at the time. The construction of a Tamoyo IV was never carried out.
The Tamoyo 3 “Under Consideration’’
What happened after the failed Tamoyo 1 trials seems to be one of the stranger affairs in tank acquisition projects of the Brazilian Army. By 1988, the Tamoyo 3 was said to have been completed, but for some reason, the Brazilian Army did not test the vehicle. In fact, the Brazilian Army would not officially test the Tamoyo 3 even once, seemingly obsessed with the Osório to such a degree that it would not consider the Tamoyo 3 until after the Osório program had definitely failed.
In 1991, the Tamoyo 3 was finally considered by the Army. The Tamoyo 3 would also face a brick wall, as the Army staff was split regarding it. One side was in favor of the Army sharing the costs of the evaluation of the Tamoyo 3, while the other side wanted to terminate the entire Tamoyo project and that the costs of the evaluation fall solely on Bernardini.
This was because the Tamoyo 3 was classified as a foreign vehicle instead of an indigenous design, since it used a lot of components that were not yet used in the Brazilian Army. These components included the L7 cannon, automatic fire extinguishing sensors, and the fire control system, among other components. The Army definitively canceled the entire Tamoyo project on July 24th 1991 without testing the Tamoyo 3 even once. With this decision, Brazil effectively shut down any possibility of an indigenous designed and manufactured main battle tank for the Army.
In a way, the Osório trials seem to have sent a signal to the Army that heavier main battle tanks, armed with guns over 90 mm, were the way forward. But this was the case for the Tamoyo 1 and not for the Tamoyo 3. Even worse, the Tamoyo 3 was only considered as late as 1991, a year after the Osório project failed and a year after Engesa filed for bankruptcy. This only further solidifies the notion that the Army decided it wanted the Osório from Engesa and not the Tamoyo 1 or the Tamoyo 3 from Bernardini.
The subsequent rejection and classification of the Tamoyo 3 as foreign seems to be hypocritical, as the Tamoyo 3 was effectively more national than the Osório. While both vehicles had almost no components that were interchangeable with other Army vehicles or components of the time, the Tamoyo 3 at least retained its suspension system, which would make it interchangeable with the M41C. This foreign marking of the Tamoyo 3 thus seems strange, as the Osório did not receive such treatment.
The reason for this hypocritical stance of the Army might have had to do with exterior factors, however. Brazil underwent a political shift in 1985. The country transitioned from a military dictatorship towards a democracy again. With this shift, the newly reformed democracy found itself in a 10-year-long battle against hyperinflation and economic disaster. To give an idea of the inflation which the democracy inherited from the military dictatorship, inflation rose to 658.91% between March 1984 and December 1985. The Brazilian economy would only start to recover from the rampant inflation around 1994. As a result of this crisis, the Brazilian government practically cut any acquisition of new material for the Brazilian Army. It is possible that the Brazilian Army would not have been able to afford the Osório initially either if it had been a success during the early 1990s and would only acquire it much later on, when the economy settled down and Engesa would have been well on its way to the Saudi Arabia order.
The cost of the entire Tamoyo 3 project is summarized in the table below, coming in at US$4.39 million in 1991. In comparison, the EE-T1 Osório project is estimated to have cost between US$50 to 100 million. The actual cost would likely be higher in theory, as design and engineering of the previous Tamoyo 1 and 2 projects should be considered as well. It is very likely that, as more components would be manufactured in Brazil, if the Tamoyo 3 was bought, the costs would have come down further due to serial production and not needing to import components. The 105 mm L7 could be made in Brazil, but Bernardini would need to acquire a machine for autofrettage, a form of cold working technique to strengthen the barrel interior so it can handle higher pressures.
Component
US$ 1991
US$ 2021
105 mm L7 LRF
50,000
100,000
Turret bearing
40,000
80,000
Suspension
300,000
600,000
Final driver
100,000
200,000
Plates and profiles
200,000
400,000
Consultancy
100,000
200,000
Project engineering
2,300,000
4,600,000
Man hours
1,000,000
2,000,000
Ammunition
200,000
400,000
Total
4,390,000
8,780,000
Impact
Even worse is that the decision to close down the Tamoyo project seems to have sealed Bernardini’s fate as well, as the company closed its doors in 2001. If the Army had decided to acquire the Tamoyo tank, whether it would have been the Tamoyo 1, 2, 3, or 4, Bernardini would probably have lived on. The acquisition of the Tamoyo would mean much more than just buying the tanks. Maintenance support, supply of spare parts, further development and upgrade programs, and more nationally produced components would all give Bernardini a steady flow of income. More importantly, Bernardini’s survival and further development of the Tamoyo would have meant that the knowledge on designing tanks and all the advancements made in the field would have been retained in Brazil.
The Tamoyo 3 especially showed a lot of potential in this regard. Although the FCS system is what held back the Tamoyo 3 the most, it is unknown what the FCS would have looked like if it was finalized. In addition, the FCS could be modernized at a later point as well by Bernardini if the Army wanted. The turret would also likely have been redesigned to provide more ergonomic protection as well. Also, taking into account the promises of a 900 hp engine or a potential refit with a ZF transmission and an MWM engine of the Tamoyo 4 program, these would have brought the Tamoyo 3 a significant mobility upgrade as well. In any case, an acquisition of the Tamoyo 3 would have left the Brazilian Army with a promising and capable main battle tank and retain the company and the know-how to potentially build future tanks.
The seeming inability to buy the Tamoyo 3, or the Osório for that matter, is usually seen as a strategic mistake by the Brazilian Army and politics. It robbed the country of the most capable land-based system companies, on which it had spent two decades to reach their apex of building their own tanks. The failure of saving either Bernardini or Engesa has caused Brazil to be dependent on foreign designs and supplies yet again.
The Tamoyo 3 Story Continues
The Tamoyo 3 story did not end here, however. With the cancellation of the Tamoyo project, a large number of components were to be returned to their respective owners, as Bernardini had borrowed them until a sale of the Tamoyo 3 would be made. These included, among other components, the Ferranti FCS, Kollmorgen sights, and the stabilization systems. The current Tamoyo 3 is thus effectively stripped of a number of important systems.
It seems that Bernardini first applied for bankruptcy in 1995 and that the Tamoyo 3 was acquired by a company Brasrodas by accident. The company had basicaly bought the entire factory including everything inside and had unknowingly bought the Tamoyo 3 tank. After dicovering they had bought a tank, which Expedito Carlos Stephani Bastos mentioned to them having bought the tank, ended up in a judicial auction. It was then bought by a private collector and was again auctioned with a starting bid of 125,000 Brazilian Real on February 2nd 2007. The Army then blocked the sale, as the vehicle was still in the Ipiranga factory and would need to move and the owner had not gone through the proper procedures and the Tamoyo 3 was not demillitarised. It was stated in a number of reports that the current owner then considered donating it to the Army, which seemingly never happened. The Army did however retain a veto to whom the vehicle could be sold. The tank was later put up for sale again for 250.000 Brazilian Real.
The Tamoyo 3 was then bought by its current owner Carlos. Carlos is a collector of armored vehicles among other vehicles and was notified by a contact that a tank was for sale in the old Bernardini factory. Carlos was apperantly well connected with the Army and after visiting the tank, personally got in contact with the local higehr ups to get all the paperwork in order. According to Carlos, it took a couple of weeks to get the paperwork done, butr in the end he bought the tank. He then adjusted the vehicle with a crew and installed an M41C powerpack as they could get the vehicle to run that way.
When the author visited the Tamoyo 3 and the Carlos Combat Car Tank Museum in September 2023, the vehicle was in excellent condition and in driving state. Sadly as the vehicle had not driven around for a while, the engine would need full servicing before being started up in order to not damage the vehicle. The writer would hereby like to express his gratitude to Carlos for letting him see the vehicle, which is one of his favorite tanks, and basicaly allow him to spend 3 hours of gathering pictures, data and the most important: armor measurements.
Conclusion
The Tamoyo 3 was the apex of the Tamoyo program and can be seen as a true Main Battle Tank in South America. Its composite armor, modern FCS for Brazilian standards, and crew protection were only rivaled by the more expensive and export-focused Osório from Engesa in Brazil. Sadly, the Brazilian Army seems to have been fully captivated by the Osório at the time, and only remembered that they had another promising tank when the Osório failed in 1991.
The fact that the Brazilian Army never tested it even once, but also that it was never tested in, for example, Ecuador, shows that the Brazilian Army had no real interest in the Tamoyo project as a whole anymore, but also that Bernardini was seemingly not in the position to carry out the project by itself. The treatment of the Tamoyo 3 as a foreign vehicle seems hypocritical. Even though the initial goal of the Tamoyo program was for as much interchangeability as possible, this goal was what doomed the Tamoyo 1 and 2 from the start as underpowered vehicles. This argument should not have weighed as heavily, especially considering the love the Osório received.
The blame cannot be fully shifted on the Army, however. Brazil was in a significant financial crisis for years at that point and even an Osório acquisition at the time would have been doubtful if it had managed to secure the Saudi Arabia contract. The shift from military dictatorship to democracy did not make the situation better either when it came to the national defense companies. The subsequent end of the Cold War and flooding of dirt-cheap surplus equipment also prevented any potential Tamoyo revival from taking place when Brazil finally recovered in the mid-1990s. Brazil would, for example, acquire M60A3 TTS tanks for as little as US$165,000 a piece in 1996.
The Tamoyo 3 was a promising and most likely a more realistic vehicle for Brazil than the Osório. It might not have been a particularly impressive vehicle, but it would have fitted the Brazilian requirements and needs perfectly. A successful acquisition would have likely seen the Tamoyo 3 in service for as long as the Leopard 1A5BR would remain in service and would have saved Bernardini, and thus retained a tank building company with experience in the country. Instead, the Tamoyo 3 ended up like the Osório and is now what could have been instead of what is.
Specifications (MB-3 Tamoyo 3)
Dimensions (L-W-H)
6.48 m (21.3 feet) and 8.9 m (29.2 feet) with the gun pointing forward, 3.29 m (10.8 feet), 2.35 m (7.7 feet) to turret top and 2.5 m (8.2 feet) in total.
Total weight
31 tonnes empty, 35 tonnes combat-loaded (34.2, 38.5 US tons)
Crew
4 (commander, driver, gunner, and loader)
Propulsion
Detroit Diesel 8V92TA 736 hp at 2,300 rpm
Suspension
Torsion bar
Speed (road)
65 km/h (40 m/h)
Armament
105 mm L7 LRF
Coaxial 7.62 mm mg or .50 caliber MG HB M2
Anti-Air 7.62 mm mg
Armor
See description
Produced
1
Special thanks to Expedito Carlos Stephani Bastos, the leading expert of Brazilian armored vehicles https://ecsbdefesa.com.br/, Jose Antonio Valls, an Ex-Engesa employee and expert in Engesa vehicles, Paulo Bastos, another leading expert of Brazilian Armored vehicles and the author of the book on Brazilian Stuarts and the website https://tecnodefesa.com.br, Adriano Santiago Garcia, a Captain in the Brazilian Army and ex-company commander on the Leopard 1 and ex-lecturer on the Brazilian Armored School, and Guilherme Travassus Silva, a Brazilian with whom I was able to endlessly discuss Brazilian Vehicles and who was always willing to listen to my near endless ability to talk about them.
Sources
Blindados no Brasil – Expedito Carlos Stephani Bastos
Bernardini MB-3 Tamoyo – Expedito Carlos Stephani Bastos
M-41 Walker Bulldog no Exército Brasileiro – Expedito Carlos Stephani Bastos
M-113 no Brasil – Expedito Carlos Stephani Bastos Jane’s armour and artillery 1985-86 Brazilian Stuart – M3, M3A1, X1, X1A2 and their derivatives – Hélio Higuchi, Paulo Roberto Bastos Jr., and Reginaldo Bacchi
L64 ammunition brochure
Moto-Peças brochure
Memoir of Flavio Bernardini
Angelo Melliani
Author’s collection
Tecnologia Militar Brasileira
Bernardini compra fábrica da Thyssen – O Globo, archived by Arquivo Ana Lagôa
The Centro de Instrução de Blindados
Personal correspondence
With Expedito Carlos Stephani Bastos, Expert on Brazilian armored vehicles
With Paulo Roberto Bastos Jr., Expert on Brazilian armored vehicles
With Adriano Santiago Garcia, a Brazilian Army captain and ex-company commander on the Leopard 1
Republic of Colombia (1993)
Armored Personnel Carrier – 1 Prototype Built
With the bankruptcy of Engesa in 1993, an uncertainty arose in Colombia regarding the readiness of their Engesa vehicles. Colombia used 128 EE-9 Cascavels and 56 EE-11 Urutus, for which the supply of spare parts was in jeopardy. The potential effects of Engesa’s bankruptcy were further aggravated by a gradual increase of FARC activity throughout the 1990s. This resulted in the development of Colombia’s very first locally designed armored vehicle, known as the Zipa. Imdicol, with the support of the Colombian Army, attempted to create what was effectively a downgraded copy of the EE-11 Urutu. They would not succeed, but would lay the basis for future Imdicol projects.
The EE-11 Urutu and Engesa’s Bankruptcy
The Urutu was Engesa’s troop transporter or armored personnel carrier (APC), designed by Engesa and the Brazilian Navy. The vehicle was designed from the ground up to be amphibious, and was approved in 1972, after successful testing in various conditions including open sea, for which it was modified with multiple snorkels, propellers, and a wave breaker.
The Urutu mounted a boomerang suspension to significantly improve its ability to traverse uneven and hilly terrain, as the wheels would always stay in contact with the ground to provide maximum traction. The APC was protected with bimetal armor, which offered improved protection over homogeneous steel armor of the same thickness. The Bimetal armor offered around 1.8 times the effective thickness of an equivalent homogeneous plate against 7.62 mm ammunition, meaning the Urutu had an effective homogeneous thickness of 21.6 mm at the front and 10.8 mm at the sides and rear against 7.62 mm fire.
Serial production began in 1973, and it managed to achieve large sales to Iraq, Libya, and most of South America. The EE-11 arrived in Colombia in 1982, as part of a deal for 128 EE-9 M4 Cascavels and 56 EE-11 M3 Urutus. The contract also included spare parts, ammunition, 17 to 22 EE-25 trucks, maintenance support, and Pilkington night vision goggles for a total contract value of US$93,328,171 US dollars (about US$270 million in 2021).
In 1990, Engesa filed for bankruptcy. Years of megalomaniac management, extreme growth, projects that went nowhere, the end of the Iraq-Iran War, the failure of the EE-T1 Osório, and the later complete disappearance of Iraq as a customer would cause the company to finally close its doors in 1993. Its assets were divided between multiple parties, such as the Brazilian government, but also smaller companies which would step in to become the new maintenance contractors for Engesa’s vehicles. These companies included Universal Ltda and Columbus International Ltda.
The Development of the Zipa
Although Colombia could have immediately contracted Universal or Columbus to continue maintaining their Engesa vehicles, it seems that they first wanted to give armored vehicle development a try themselves.
There are a couple of reasons which might explain why Colombia chose this route. The first was to obtain know-how in the country on building these types of vehicles, and like Brazil before it, in order to attempt to supply its armored forces with locally produced armored vehicles to be more independent. Another reason is that Colombia considered that they could lose EE-11 Urutus against the Fuerzas Armadas Revolucionarias de Colombia – Ejército del Pueblo ((FARC-EP, though more commonly known simply as FARC) (Revolutionary Armed Forces of Colombia – People’s Army)) in a significant enough number, and they would need replacements, of which none would be available.
The FARC (Fuerzas Armadas Revolucionarias de Colombia, Revolutionary Armed Forces of Colombia) is a Marxist-Leninist guerilla organization founded in 1964. The FARC can trace its roots to the PCC (Partido Comunista Colombiano, Colombian Communist Party), which was founded in 1930. The PCC established itself in Colombia as proponents of improved conditions for the working classes. The PCC effectively formed in rural territories within Colombia to enable the rural populations to defend themselves from state-sponsored violence against the working classes and small landowners (farmers). Tensions between the PCC and PLC (Partido Liberal Colombiano, Colombian Liberal Party) on the one hand and the Partido Conservador Colombiano (Colombian Conservative Party) on the other rose to a decade long civil war in 1948, known as La Violencia. By the end in 1958, the war had ended in a stalemate which had claimed the lives of 200,000 people, partially as a result of peasants from different political factions fighting each other for agricultural land.
During the 1960s, the Colombian government, backed by the United States, attempted to reclaim the rural territories which had been founded by the PCC, and in 1964 attacked the rural territory known as Marquetalia. The region was overrun by about 16,000 Colombian troops, while the total defense force of the territory, consisting of supposedly 48 men, managed to slip away. These 48 fighters founded the FARC in 1966, essentially forming a more organized military wing of the PCC. The FARC grew in numbers and eventually called themselves the FARC-EP (Fuerzas Armadas Revolucionarias de Colombia – Ejército del Pueblo, Revolutionary Armed Forces of Colombia – People’s Army) which became more aggressive, initiating large scale operations and attacks against the Colombian Army. The FARC-EP funded their organization through kidnappings, the traffic of illegal drugs such as cocaine, and taxation in areas they controlled, among other means. Through multiple peace talks and cease-fires over the years, the FARC was eventually dissolved in 2017, although about 2,500 FARC-EP fighters are still operating against the Colombian government.
Development of the Zipa began somewhere in 1993, although initial steps might have been taken as early as 1990, with the beginning of Engesa’s bankruptcy. It was developed by Imdicol with support of the Intendencia General del Ejército (Army Quartermaster General’s Office), Brigada de Apoyo Logístico (Logistics Support Brigade), la Dirección de Armamento (Directorate of Armaments), Escuela de Caballería (Cavalry School), and the Batallón de Mantenimiento (Maintenance Battalion). The goal was to create a locally designed and manufactured vehicle to replace the EE-11 Urutu from service. About 70% of the Zipa was locally produced and 30% was imported. Most electrical and mechanical components were adapted from off-the-shelf heavy duty truck components. The steel used for the Zipa’s armor was homogenous instead of the Urutu’s bimetal. A number of components were said to have been repurposed from a destroyed Cascavel.
An EE-9 Cascavel had been destroyed not too long before the development of the Zipa began, by an IED of the ELN guerilla (Ejército de Liberación Nacional, National Liberation Army). The perpetrators, who were captured a couple of weeks later, stated that they had stolen 50 kg of dynamite from a mine before the attack. If the full 50 kg was used during the attack is unknown, but if it was, the Cascavel came out of the explosion relatively well off, which might suggest that it drove at a sufficient distance to not be a complete write off. The registration of the EE-9 was ‘EJC-1-2042’ of the Grupo de Caballería Mecanizado N.1 (First Mechanized Cavalry Group).
It is said that a range of components were repurposed from the EE-9 Cascavel for the Zipa. Which components were used exactly is unknown, but it is likely that these included systems of the driver, the engine, suspension components, the ET-7,62 turret, and potentially, a semi-restored boomerang suspension.
A single prototype was completed some time before May 29th 1993. The Zipa was presented at the 5th Expomilitar, a military exhibition, at Corferias. There, the prototype was baptized a ‘Zipa’ by a car designer named Eduardo Fajardo, who worked with Imdicol. The author of this article was unable to find any exact information about Eduardo Fajardo, but the name Fajardo is a frequent name that comes up in relation with Imdicol (suggesting its a family business and Eduardo might have been one of the first CEO’s), and the current CEO is Victor Hugo Fajardo. This suggests that Eduardo Fajardo might have been the CEO of Imdicol at the time.
The Zipa was extensively tested, which ended in unsatisfactory results. The vehicle was too heavy for its suspension, the engine did not have enough torque to overcome slopes and the vehicle was underpowered in general. It was not amphibious, which was initially planned, nor were the wheels suitable for the type of vehicle. The suspension system itself was also said to not have been suitable and used too many components from commercial vehicles.
Interestingly, the vehicle appears to mount a boomerang suspension, but according to an ex-volunteer at the Colombian Army who drove the Zipa in June 1994, the suspension did not function like a boomerang suspension. It is possible that the Zipa never had a boomerang suspension, but mounted a suspension to look like one, or that the boomerang was damaged to such a point that it was only salvageable without its boomerang feature working. The ex-volunteer also noted that the vehicle had good speed, but that the overall quality of the workmanship was poor.
Imdicol
Little is known about Imdicol, except that it was founded at some point between 1983 and 1985. Considering the recurring name of Fajardo, it is likely that the company is a family business. The first project of Imdicol was the modernisation of 16 Colombian Army M8 Greyhounds, by remotorising them with a Detroit Diesel engine and Alison automatic transmission, and arming the vehicles with a M55 quad .50 machine gun turret.
After this, the company seems to have gotten enough experience to try and take on the development of the Zipa. After the Zipa, the company would develop a range of wheeled armored vehicles, and is now a company focussed on equipment and armored vehicles for special police forces.
The Zipa in Detail
The Zipa was 6.3 meters (20.6 feet) long, 2.7 meters (8.86 feet) wide, and 2.4 meters (7.87 feet) high, and weighed 10 tonnes empty and 12 tonnes (11-13.2 US tons) combat-loaded. The Zipa had a crew of 2, a driver and a commander, and could transport between 14 to 16 soldiers. This is a significant number, as the Urutu could transport 10 soldiers. It is likely that the Zipa was in actuality meant to transport just 12 soldiers instead. This has to do with the relatively minor length increase and the amount of portholes on the sides of both vehicles. The Colombian EE-11 M3 Urutus had 5 portholes on each side for the ten soldiers. This porthole design was continued on the Zipa, but the Zipa had 6 portholes on each side, signifying the possibility of carrying 12 soldiers instead of 14 to 16.
Comparison table
Imdicol Zipa
EE-11 Urutu
Length
6.3 meters (20.6 feet)
6.1 meters (20 feet) long
Width
2.7 meters (8.86 feet)
2.59 meters (8.5 feet)
Height
2.4 meters (7.87 feet)
2.4 meters (7.87 feet) ET-7,62 commander’s turret
Weight
10 tonnes empty and 12 tonnes (11-13.2 US tons) combat-loaded
12.6 tonnes (13.9 US tons) combat-loaded
Hull and Armor
The hull of the Zipa was manufactured from homogenous steel plates at more or less the same angles of the Urutu, so about 70º from vertical for the upper front plate and 30º from vertical for the lower front plate. The armor of the Zipa is unknown, but considering its overall dimensions and weight are close to the Urutu, it is likely to be around the same thickness. This would mean about 12 mm (0.5 inch) of armor at the front and 6 mm (0.25 inch) on the sides and rear. It is important to note that the Urutu used bimetal armor instead of homogeneous armor like the Zipa. This means that, against 7.62 mm bullets, the Urutu would have an effective armor of about 21.6 mm (0.85 inch) and 10.8 mm (0.43 inch) while the Zipa would have an effective armor of 12 mm (0.5 inch) and 6 mm (0.25 inch). As such, the Urutu provided more effective armor for about the same weight compared to the Zipa.
The Zipa sported two sets of lights which were integrated in the hull, with a black-out marker and headlight on each side. A large part of the right upper front plate is occupied by a large hatch which gives access to the engine. On the left is the driver’s station, with a foldable windscreen and a driver’s vision structure, sharing many design features with the Urutu.
In addition, the vehicle was outfitted with a side mirror on each side. The Zipa had two doors on each side of the hull and also incorporated 6 portholes on each side so that the soldiers could shoot from the inside of the vehicle. The vehicle had its exhaust on the right side of the vehicle, with the pipe going all the way to the penultimate rearmost porthole. It also seems to have either a siren or horn installed on the front right side of the vehicle.
The rear of the Zipa seems to have two rear lights on each side integrated in the hull, and a large door in the middle for the passengers. The door offers a large sight for the troops to look outside and also an additional porthole. The door design seems to have been based on the Urutu door as well.
The hull top design also seems to be a direct copy of the EE-11 Urutu. Although no direct pictures of the top of the Zipa exist, based on pictures from the outside and interior, the vehicle has 4 large hatches for the soldiers on the top rear of the vehicle. In between these hatches, on each side, was also a ventilation cover. The commanders’ ET-7,62 turret, either taken from a EE-9 Cascavel or a Colombian copy, was installed on the left front side of the hull top. On the right were 4 extra ventilation slides. In front of the ET 7,62 turret was the driver’s rotating hatch. The interior rear of the vehicle is very much like the Urutu, with two sets of benches on both sides of the vehicle.
Mobility
The engine which powered the Zipa is unknown. Based on a picture of the engine, it is somewhat likely that a Detroit Diesel 6V53 210 hp@2,800 rpm engine was used. This theory is further supported by the engine used in Colombia’s Urutus and Cascavels, which were also Detroit 6V53 engines, and due to the various components of the wrecked EE-9 that were integrated in the Zipa. What is at least clear is that the Zipa used a V-style engine. The transmission is also unknown, but is stated as an Imdicol 6×6 transmission by multiple sources. It could also have been an Allison MT-643 which was used on the Urutus and Cascavels and might have been salvaged from the destroyed Cascavel, and on later vehicles built by Imdicol.
It can be concluded that, if the Detroit engine was used, the mobility issues of the Zipa were not to blame on the engine. The same engine was used on the Urutu and Cascavel, so it is much more likely that the components in between engine and the final drives were the problem instead. It is possible that the drive and suspension components were also salvaged from the EE-9 Cascavel, of which some might have been damaged, like the boomerang suspension, potentially explaining the mobility issues.
The Zipa is said to have been able to drive 100 km/h (62 mph) on roads and had an operational range of 600 km (373 miles). It had 6 wheels which may have been run-flat or bulletproof, although sources disagree on this matter. If they were bulletproof, the wheels were supposedly filled with a gelatinlike substance. It is likely that the suspension installed was either a restored version from the destroyed Cascavel, thus losing its boomerang ability, that it was a concept suspension, or that it was a different type of walking beam suspension. The suspension used springs and leaf springs for shock breaking.
Turret and Armament
The Zipa mounted what seems to be a copy of Engesa’s ET-7,62 commander’s cupola or used the ET-7,62 from the destroyed EE-9. The ET-7,62 was armored with 8 mm bimetal steel plates (which would most likely be turned into homogenous steel for the Colombian version if it was a copy), and had a turret ring of 0.68 meters.
It had 3 periscopes and could be armed with a 7.62 mm machine gun. The Zipa was supposed to be armed with a 12.7 mm machine gun (most likely an M2 Browning Heavy Machine Gun). The machine guns could be fired remotely from the inside of the vehicle if needed. The turret would also be outfitted with two pairs of smoke launchers. The cupola was accessed through a large hatch that more or less constituted the entire rear and side of the turret. The periscopes supposedly used VN Infrared Systems as night sights. It is unknown if this was also the case for the driver.
Fate
When the vehicle was completed in 1993 and subsequently tested, a number of issues regarding its mobility came to light. If this had to do with the engine, according to Colombian sourcing, could be somewhat questioned if the engine happened to be a Detroit 6V53. It is also interesting if the ET-7,62 turret was actually copied, or taken from the destroyed EE-9, and if the boomerang suspension was salvaged from the same EE-9 and repaired to be mounted on the Zipa as a temporary suspension. If this is the case, it would also be very likely that components such as the transmission and engine could also have been used from this Cascavel to save costs and development time.
The Zipa project seems to have been abandoned after these trials. It is very likely that, by the end of the trials, the situation around Engesa’s bankruptcy had been stabilized and that companies such as Universal Ltda and Columbus Ltda had managed to cement themselves as the new maintenance and refurbishment companies of the Engesa vehicles.
It is very likely that the Colombians started running the numbers and figured out that maintaining the Urutu was cheaper than building their own APC and that they may not have lost as many Urutu against the FARC as initially predicted. In addition, even if all the mobility issues were solved by Imdicol by using more heavy-duty components, the Zipa would still be an inferior vehicle to the Urutu. The Zipa would only be able to compete with the Urutu if Imdicol started using bimetal armor instead of homogeneous steel and if the vehicle would get amphibious capabilities. If the Zipa had kept using homogeneous armor and the vehicle went into service, the Colombians would effectively be replacing the Urutu with worse vehicles.
The Zipa project was canceled and the vehicle remains at the Escuela de Caballería (Cavalry School), where it was used as an instruction vehicle, but is now part of the museum. It seems that, somewhere after June 2019, the Zipa was painted in a desert livery.
The project was luckily not a waste of resources, as the overall design was adapted in Imdicol’s next project, known as the Aymara. Two Aymara were built and are still in use. Interestingly, the Aymara was co-developed with Columbus Ltda, and both Columbus and Universal would end up doing either maintenance or refurbishments for the Colombian vehicles.
Conclusion
In the end, Colombia’s first attempt to build an armored vehicle had failed. The concept of the Zipa was not terrible, as it was almost an identical copy of the Urutu. The main issue was the components used to build the Zipa. The suspension components were not fit for a vehicle of this weight, and the usage of homogeneous steel meant that the Zipa was less armored than the Urutu it was meant to replace.
These factors and the costs of acquiring new vehicles versus maintaining old vehicles with the rise of Columbus and Universal, seems to have been deciding factors to not go forward with the Zipa and keep using the Urutues instead. As such, the Zipa project came to a close and Imdicol went on to develop the Aymara.
Specifications Zipa
Dimensions (L-W-H)
6.3 meters (20.6 feet) x 2.7 meters (8.86 feet) x 2.4 meters (7.87 feet)
Total weight
12 tonnes (13.2 US tons)
Crew
2+12-16 (Driver, commander, 12 to 16 soldiers)
Propulsion
Unknown, might be a Detroit 6V53 210 hp diesel engine
Speed (road)
100 km/h (62 mph)
Operational range
600 km (373 miles)
Armament
12.7 mm heavy machine gun
Armor
Unknown, likely to be similar to the Urutu but homogeneous instead of bimetal
Produced
1 prototype
Special thanks to Rodolfo Alberto Riascos Rodrigues, the ex-volunteer who drove the Zipa in 1994. His information and experience has been invaluable to tell the story of the Zipa.
Federative Republic of Brazil (1986)
Medium Tank – 1 Built
With the initiation of the Tamoyo 1 project by Bernardini and the Brazilian Army in 1979, Brazil set off designing a new family of tanks for the country. The Tamoyo 1 was designed to have as many parts in common with the existing M41 Walker Bulldog fleet as possible. This meant that the Tamoyo 1 used a CD-500 transmission from the late 1940s/early 1950s and a 500 hp DSI-14 diesel engine. Effectively, the Tamoyo 1 was limited in its potential capabilities by the Army’s requests.
Sometime between 1979 and 1984, Bernardini decided that they wanted to offer the Tamoyo with a modern transmission as well. They secured the construction of a Tamoyo 2 in a contract with the Army, and installed a HMPT-500 transmission in the vehicle. In the end, the Tamoyo 2 would end up serving more as a testbed than anything else, and would be scrapped by the end of the Tamoyo program in 1991.
Designations
The Tamoyo had various designations to denote the stages of the project. The first stage of the Tamoyo was designated X-30, with the ‘X’ standing for prototype and the ‘30’ for its 30 tonnes weight. This designation was used until the first working prototype of the Tamoyo 1 was delivered in May 1984.
After the initial mock-up stage, the vehicle received a new designation: the MB-3 Tamoyo, named to honor the Tamoyo Confederation of the Tupinambá people. The Tamoyo Confederation was an alliance of various indigenous tribes of Brazil in response to the slavery and murder inflicted on the Tupinambá tribes by the Portuguese discoverers and colonizers. The Tupinambá people fought against the Portuguese from 1554 to 1575. A peace treaty between the two warring parties was signed in 1563, although the fighting did not completely end until in 1567, after the Portuguese colonists were sufficiently strengthened to tip the scales in completely in their favor. The Tamoyo Confederation was effectively wiped out by 1575. Tamoyo means grandfather or ancestor in the Tupi language.
The MB-3 Tamoyo has 3 main sub-designations: Tamoyo I, Tamoyo II, and Tamoyo III (named Tamoyo 1, 2, and 3 in this article for ease of reading). The Tamoyo 1 refers to the Tamoyo meant for the Brazilian Army, armed with a 90 mm BR3 gun, DSI-14 500 hp engine and a CD-500 transmission. The Tamoyo 2 was exactly the same as the Tamoyo 1, except that it used a modern HMPT-500 transmission. The Tamoyo 3 refers to the upgraded export version armed with a 105 mm L7, with an 8V-92TA 736 hp engine, a CD-850 transmission, and armored with composite armor instead of only steel. The Tamoyo 3 would eventually be proposed to the Brazilian Army as well in 1991, a year after the failure of the EE-T1 Osório.
The Tamoyo 2 would receive an additional designation in 1987. At some point, the Tamoyo 2 received the 105 mm turret of the then unfinished Tamoyo 3 for a military exposition. The sign next to the Tamoyo 2, calls the vehicle the Tamoyo-II-105. In this article, it will be called Tamoyo 2-105 for ease of reading.
The 8 envisioned vehicles and the first prototype received individual designations as well. These designations went from P0 to P8 and had sub-designations regarding their models as well. The first working prototype was designated P0 and held the model designation TI-1, where ‘TI’ refers to Tamoyo 1 and the ‘1’ refers to the first Tamoyo 1 vehicle. There were also three support vehicles envisioned: bulldozer, bridgelayer, and engineering vehicle. These are denoted by VBE (Viatura Blindada Especial, English: Special Armored Vehicle)
Prototype
Model designation
P0
TI-1
P1
TI-2
P2
TII
P3
TI-3
P4
TIII
P5
TI-4
P6
VBE Bulldozer
P7
VBE Bridge Layer
P8
VBE Engineering
Origin
In 1979, the Brazilian Army released a set of requirements for a new national tank. The CTEx (Centro Tecnológico do Exército, English: Army Technology Centre), which Division General Argus Fagundes Ourique Moreira led, was responsible for the acquisition of funds from the Army for the project, and to give input in the selection of components, design, and companies working on the new tank. The CTEx effectively participated in this project to ensure that the Army would receive a feasible Carro de Combate Nacional Médio (National Medium Combat Car/tank, the Brazilian Army names all their tanks combat cars).
This project would be known under the designation X-30, with the ‘X’ standing for prototype and the ‘30’ for its 30 tonnes weight. One of the key requirements apart from weight and width, was a high level of interchangeability between components of the available Brazilian M41 Walker Bulldog fleet and the potential Charrua Armored Personnel Carrier from Moto-Peças, which was intended as an M113 replacement. The main components selected for this new tank were a CD-500 transmission, DSI-14 engine, a Brazilian version of the 90 mm F4 designated Can 90 mm 76/90M32 BR3, and a copied M41 suspension system. Of these main components, the transmission, engine and suspension were interchangeable with the upgraded M41B and M41C fleet of Brazil.
The XM4 program
The main issue with the X-30 was the age of the CD-500 transmission. The CD-500 was already a 30 year old design by the time the development of the Tamoyo was initiated in 1979. Bernardini thus concluded that it was necessary to offer a modern transmission for the Tamoyo besides the CD-500. The company selected the HMPT 500-3 transmission, then used for the Bradley and the XM4 light tank project, among others, by the United States, and entered negotiations with General Electric.
In the early 1980s, the United States started looking for a new light tank to replace the M551 Sheridan. This program was known as the XM4, for which the Commando Stingray, Teledyne Continental Motors ASP, Food Machinery and Chemical Corporation CCVL, the Swedish IKV-91, and the later Food Machinery and Chemical Corporation Armored Gun System (later known as the M8) were proposed. A range of components used for the XM-4 tanks can be found in the Brazilian Tamoyo as well.
The Bernardini Engineers were most likely inspired by the XM4 tanks, as they were said to have been present during trials and followed the project’s developments. It is hard to not notice the similarities between some of the XM4 specifications of the Stingray and the XM8 and the eventual Tamoyo 3 (the final stage of the Tamoyo program which was initially designed with export in mind). Both programs would use a low recoil force 105 mm gun, a Detroit Diesel 8V-92TA engine, an HMPT-500-3 transmission, had the same speed, the same operational range, and the same ground pressure.
The main difference was that the Tamoyo 3 was more heavily armored in both base armor configuration and with composite armor, causing the Tamoyo 3 to be about 10 tonnes heavier than the air-transportable XM4 projects. It is very likely that the Bernardini engineers followed the XM4 program while designing their own Tamoyo 3 for export, in an attempt to make it as interesting as possible for the export market and to design a proper main battle tank for South American standards. At the same time, it is also very likely that Bernardini came in closer contact with the HMPT-500-3 transmission through the XM4 program for the Tamoyo 2 as well.
The Tamoyo 2 Mock-Up?
According to Flavio Bernardini, at the time one of Bernardini’s CEOs, Bernardini also produced a mock-up of the Tamoyo 2. Although this is probably true, it does not make much sense. The only difference between the Tamoyo 1 and the Tamoyo 2 is the transmission of the vehicle. The rest of the design remained unchanged in the initial stages.
Even more confusing, the picture of the mock-up is dated August 1983. In the picture, the lower hull is shown to be more or less completed, but the turret is a styrofoam mock-up. This styrofoam mock-up is almost exactly the same as the X-30 mock-up except for a few details, such as lifting eyes. In addition, the gun presented on the Tamoyo 2 mock-up is a dummy of the 76 mm from the M41. The rear side hull plate does look different from the eventual X-30 mock-up, as the rear part does not widen as gradually.
Another detail which makes this mock-up confusing is that the contract for the development of the Tamoyo 2 was signed in 1984 and not 1983. It is possible that Bernardini proposed this upgrade earlier on, which could explain the existence of the mock-up.
Finally, it is unknown what happened with the Tamoyo 2 mock-up. This makes it impossible to either fully prove or disprove that a Tamoyo 2 mock-up existed. For all we know, it was scrapped, or it was integrated with the current X-30 mock-up preserved at the CTEx.
The writer thus somewhat questions the existence of the Tamoyo 2 mock-up and suggests that it might just be the X-30 mock-up in early stages. This would not be unlikely, as the contract for the production of the Tamoyo prototypes between the Army and Bernardini was only signed in March 1984. The styrofoam turret suggests that, as of late 1983, no steel mock-up turret was available, and the slight change in the hull design suggests further development in this regard as well. This means that the general design of the hull and turret, and the mock-up itself, would have been finalized in the coming 7 months when the contract was signed for the prototype production in late March 1984.
Considering the mock-up in the picture is outfitted with tracks, it is also a possibility that the Tamoyo 2 mock-up was later converted to the Tamoyo 2. But this also seems somewhat unlikely, because it would not make sense to convert the Tamoyo 2 mock-up into the Tamoyo 2, but not do this for the Tamoyo 1 by converting the X-30 mock-up.
The writer cannot definitively prove his theory, and would like to add that he does not want to imply that Flavio Bernardini is wrong, as he was present at the time and involved with the project. The writer implies that the picture might have been labeled incorrectly and that, over the period of 20 to 30 years, the exact details might have faded. The writer thus questions the logic and practicality of designing a mock-up for basically the same vehicle, and provides an alternative chain of events to what might have happened. If the Tamoyo 2 mock-up existed, it is very likely that it was either scrapped or converted into the Tamoyo 2.
The Tamoyo 2 Project Begins
What is known is that Bernardini looked into a potential Tamoyo with an HMPT-500 transmission before March 27th, 1984. It is also very likely that Bernardini had already contacted and opened negotiations with General Electric for the transmission before this date as well. The construction of a Tamoyo 2 prototype was made official with the signing of a contract for the construction of 8 Tamoyo prototypes on March 27th, 1984. These vehicles included 4 Tamoyo 1s, a single Tamoyo 2, and three engineering vehicles.
With the contract signed, work on the Tamoyo 2 began. General Electric provided a single HMPT-500-3 transmission to Bernardini for testing, including all the technical support the company needed. The transmission was coupled with the Scania DSI-14 turbocharged V8 500 hp diesel engine. General Electric engineers visited Bernardini several times to assist in the installation and the initial testing of the transmission.
The hull of the Tamoyo 2 was completed around 1986 and was subsequently tested as a sample for a HMPT powered Tamoyo. According to sources, the Tamoyo 2 briefly received the same 90 mm armed turret as the Tamoyo 1, but would be presented with the turret of the Tamoyo 3 in 1987 before May 10th, at an exposition. The Tamoyo 2 thus effectively served as a testbed for both the transmission and the new 105 mm L7 armed turret meant for the Tamoyo 3 for export. In a way, the 105 mm armed Tamoyo 2 was the apex of the Tamoyo 2 program.
The MB-3 Tamoyo-II-105
The Tamoyo with the Tamoyo 3 turret was designated as MB-3 Tamoyo-II-105 when it was presented at a military exposition, together with the Charrua Armored Personnel Carrier. The sign which accompanied the vehicle stated that it had a 500 hp DSI-14 engine, an HMPT 500 transmission, a maximum speed of 67 km/h, could climb a ramp of 60 degrees and a 30-degree ramp from the side, had an operational range of 500 km, a 105 mm L7 gun, a coaxial machine gun, an advanced fire-control system by Moog AEG and Ferranti Computers, could fire a wide range of ammunition and weighed 31 tonnes combat-loaded.
Effectively, the Tamoyo 2-105 was marketed the cheap version of the Tamoyo 3. The Tamoyo 3 was offered with an HMPT-500 and a CD-850 transmission, albeit paired with a General Motors 8V-92TA 736 hp diesel engine instead, allthough the DS-14 was still offered as well. The Tamoyo 2 would also never receive the hull mounted spaced armor package which the Tamoyo 3 was planned to receive. As such, the Tamoyo 2 remained as a test bed, and its development seems to have been canceled after the 105 mm turret was removed and mounted on the Tamoyo 3 around 1989.
On May 10th 1987, the Tamoyo 2-105 was presented at the Cavalry Festival in Rio Grande do Sul. The vehicle was shown to the Army Minister at the time, Leônidas Pires Gonçalves (1985-1990), and the commander of the Comando Militar do Sul (Southern Military Region), General de Exército (equivalent to a four-star General) Edison Boscacci Guedes, by Flávio Bernardini. The Tamoyo 2-105 does not seem to have been tested.
Looking at the pictures of what is called Tamoyo 3 by sourcing, something strange can be noticed. The vehicle presented at the Cavalry Festival has the exact same camouflage pattern as the Tamoyo 2-105 and also shares the exact same exterior appearance of other components. Another strange detail is that the hull bears the CTEx logo, even though the Tamoyo 3 was developed by Bernardini without Army help or funding, but this might also have been used to recognise the Army support to get the Tamoyo program off the ground in the first place. Additionally, the author visited the Tamoyo 3 and noticed that the hull of the Tamoyo 3 was a completely different design concept and that the vehicle had a manufacture plate from 1989.
Better pictures of the side rear help in determining the vehicle precisely, as the Tamoyo 2-105 and Tamoyo 3 have a few external differences, like a hatch on the side rear which is round on the Tamoyo 2, but an ellipse on the Tamoyo 3. In addition, the engine deck of the Tamoyo 2-105 seems to have a more angled inclination than the Tamoyo 3.
The HMPT-500-3 vs the CD-500-3
The HMPT-500-3 transmission offered a range of advantages over the CD-500-3. The most notable were horsepower, weight, and space. The HMPT-500-3 transmission could generate up to 600 hp, while the CD-500 was limited to 500 hp. For the Tamoyo 1 and 2, this would effectively mean a hp/tonne ratio increase from 16.67 to 20 hp combat-loaded. In addition, the HMPT-500 transmission occupied 0.62 m3 compared to 0.85 m3. The reduced size meant that the HMPT weighed 862 kg dry (without hydraulic fluid), while the CD-500 weighed 925 kg dry.
The HMPT was also a more efficient transmission over the CD-500. It, for example, determined the hp and torque ratio provided by the engine and the load required by the vehicle to provide better fuel economy, along with an infinitely variable transmission ratio to provide the best torque and hp ratio at as little rpm as possible over three gears (or ranges). Effectively, the higher the gear, the more efficient the transmission, but in every individual gear, the transmission also adapted to provide the most favorable transmission ratio. This meant that the transmission would always operate on the best torque output as possible, while the CD-500 transmission would only operate at maximum torque at a specific point of its gear. The HMPT transmission could also use the engine as a brake by reversing the hydraulic system.
The Tamoyo 2 in Detail
The exact weight of the Tamoyo 2 is uncertain, as there is no document that clearly specifies the weight of the Tamoyo 2. Two weights do recur in documentation, which are 29 and 30 tonnes (32 and 33 US tons) combat loaded. Considering the prototype was designated as X-30, it is quite likely that the actual combat weight was 30 tonnes. Considering the combat weight of the Tamoyo 3 was 31 tonnes (34 US tons) and the empty weight was 29 tonnes, it is estimated that the Tamoyo 2’s empty weight would be around 28 tonnes (30.9 US tons). The Tamoyo 2-105 would weigh 29 tonnes empty and 31 tonnes combat loaded.
The vehicle had a hull length of 6.5 meters (21.3 feet) and was 8.77 meters (28.8 feet) long with the gun pointing forward. It was 3.22 meters (10.6 feet) wide, and 2.2 meters (7.2 feet) tall to turret top and 2.5 meters (8.2 feet) tall in total. The Tamoyo 2-105 was 8.9 meters (29.2 feet) long with the gun pointing forward and 2.35 meters (7.7 feet) tall to the turret top and 2.5 meters (8.2 feet) tall in total.
The tank would have been operated by a four crew members, consisting of the commander (turret middle right), the gunner (turret front right, in front of the commander), loader (turret middle left), and the driver (front hull left).
Hull
The hull consisted of a welded homogenous steel construction. With the help of Adriano Santiago Garcia, a Captain in the Brazilian Army, ex-company commander on the Brazilian Leopard 1s, and former instructor at the CIBld (Centro de Instrução de Blindados, Armor instruction center), who knew someone present at the CIBld, the writer has been able to uncover a sizable amount of the armor thickness values of the Tamoyo 1 and 2 by measuring the plate thicknesses, which up to now had not yet been published. The armor is heavier than the M41 Walker Bulldog and was meant to stop 30 mm rounds from the front and 14.7 mm on all sides.
Location
Thickness
Angle from vertical
Relative thickness
Hull
Upper Front
40 mm (1.6 inch)
60º
80 mm (3.15 inch)
Lower front
40 mm (1.6 inch)
45º
57 mm (2.25 inch)
Sides
19 mm (0.75 inch)
0º
19 mm (0.75 inch)
Rear
?
0º
?
Top
12.7 mm (0.5 inch)
90º
12.7 mm (0.5 inch)
The Tamoyo had a headlight and blackout marker on both sides of the upper front hull, with a siren installed behind the right set of lights. Two lifting eyes were welded on both sides of the side upper front plates. In the middle of the upper front plate, in between the sets of lights, were mounting points for a set of spare tracks. The driver was situated on the left side of the upper front plate, and had 3 vision blocks available. The driver’s hatch was a sliding hatch and the driver also had access to a hull escape hatch.
The hull side provided mounting points for the installation of side skirts, which consisted of 4 sets of skirts on each side. The early versions of the side skirts were made from steel, but would later incorporate materials like rubber and aramid fibers to improve the effectiveness against certain projectiles. The Tamoyo 2 does not seem to have mounted its side skirts.
The Tamoyo had two rear lights on the rear hull plate, and a towing hook on the lower rear plate. In addition to the towing hook, two brackets were installed on this plate and on the lower front plate as well.
Mobility
The Tamoyo 2 was powered by a DSI-14 turbocharged V8 500 hp diesel engine. This liquid-cooled intercooler engine provided 500 hp and 1,700 Nm (1250 ft-lbs) at 2,100 rpm. This engine gave the Tamoyo a power-to-weight ratio of 16.6 hp/ton (16.1 hp/ton for the Tamoyo 2-105). The Tamoyo 2 used a General Electric HMPT-500-3 hydromechanical transmission, which had 3 ranges forward and 1 for reverse. Combined, this powerpack gave the Tamoyo a top speed of 67 km/h (40 m/h) on level roads. It had a fuel capacity of 700 liters (185 gallons), which gave it a range of approximately 550 km (340 miles). The Tamoyo 2-105 had a range of 500 km.
The Tamoyo used a torsion bar suspension with 6 road wheels and 3 return rollers on each side. It had 3 additional shock absorbers installed, with 2 mounted on the front two road wheels and 1 on the last road wheel. The torsion bars were previously developed by Eletrometal for the M41B program. These torsion bars were made from 300M alloy steel, which was also used for the torsion bars of the M1 Abrams. The idler wheel was mounted on the front side of the vehicle, while the drive sprockets were installed in the rear.
The Tamoyo used Brazilian copies of the T19E3 tracks produced by Novatraçao. The T19E3 tracks had a width of 530 mm (20.8 inch), and a ground contact length of 3.9 meters (12.8 feet). This gave the Tamoyo a ground pressure of 0.72 kg/cm2 (10 lbs/in2) and a trench crossing ability of 2.4 meters (7.9 feet). The tank had a ground clearance of 0.5 meters (1.6 feet) and could climb a 0.71 meters (2.3 feet) tall vertical slope. It could climb a slope of 31 degrees, and be operated on a side slope of about 17 degrees. The vehicle had a fording capability of 1.3 meters (4.3 feet) and could neutral steer as well.
Turret
The Tamoyo 2’s 90 mm turret was armored with welded homogeneous steel plates inclined at various angles. The turret was meant to protect the Tamoyo from frontal 30 mm and all-round 14.7 mm fire. Like with the hull armor, these armor values were uncovered with the help of the writer’s contacts in the Brazilian Army.
Location
Thickness
Angle from vertical
Relative thickness
Turret
Gun Shield
50 mm (2 inch)
45º
70 mm (2.75 inch)
Front
40 mm (1.6 inch)
Presented armor angle when firing at the front:
Front top: 60º
Front side: 67º
Front bottom: 45ºAngle of the front side when firing at the side:
20º
Presented relative armor when firing at the front:
Front top: 80 mm (3.15 inch)
Front side: 100 mm (4 inch)
Front Bottom: 57 mm (2.25 inch)Relative armor of the front side when firing at the side: 43 mm (1.7 inch)
Sides
25 mm (1 inch)
20º
27 mm (1 inch)
Rear (not including storage box)
25 mm (1 inch)
0º
25 mm (1 inch)
Top
20 mm (0.8 inch)
90º
20 mm (0.8 inch)
The Tamoyo turret was practically shaped like a Leopard 2 turret, because of the usage of flat plates instead of an intricately shaped side plate. It had a turret ring diameter of 2 meters (6.5 feet). The turret had 2 hatches, 1 for the commander and gunner, and one for the loader. The hatch for the commander was located on the middle right of the turret, while the loader’s hatch was located on the middle left. The gunner was located in front of the commander and had a passive day/night periscope located in a depression of the turret top. In addition, the gunner also had access to a direct sight telescope coaxial to the main gun. The commander had 7 periscopes available, which were passive day/night sights. A laser range finder was mounted on top of the main gun.
A set of 4 smoke dischargers were mounted on both sides of the turret front. The Tamoyo also had 2 handles on each side, behind the smoke dischargers, to enable the crew to climb on the turret. A pickaxe was mounted on the right side of the turret, behind the handles. Various mounting points for boxes and tools were available on the rear side plate of the turret as well, including a lifting eye on each side on both the rear and front side plates. Finally, a storage box was mounted on the rear of the turret and a jerrycan was then mounted on both sides of the storage box.
The turret top configuration seems to have undergone some minor changes during the development. Two mounting points for antennas were located on each outer side on the rear top plate. In another turret design, the left mounting point was located just behind the loader’s hatch instead. In between the antenna mountings, was the inlet for the ventilation system, as the Tamoyo had a Nuclear Biological Chemical (NBC) system available. In the middle were the two hatches and in front of the loader’s hatch was another component of which its exact purpose is unknown. In a single picture of the Tamoyo 2 with the 105 mm turret, this location is outfitted with a meteorological system.
The turret was armed with the BR 90 mm gun and a coaxial 12.7 mm heavy machine gun. In addition, the commander’s station could be armed with a 7.62 machine gun for Anti-Air purposes. The turret had an electrical and manual turret drive and the gun had an elevation of 18 degrees and a depression of 6 degrees.
The armor of the 105 mm turret of the Tamoyo 2 would have consisted out of steel with cavities filled or acting as composite or spaced armor, more details can be found in the Tamoyo 3 article. The thickness of the gun shield is unknown as the author was unable to get a proper measuremnt. It is likely this was atleast 235 mm LoS (Line of Sight) as that is the LoS presented by the cheeks, the rest fo the front was armored by about 55 mm of plate steel. The turret cheeks were armored with 2 plates of about 27 mm each stacked together, a 50 mm cavity, and again 2 plates of about 27 mm each stacked together (55+50+55), which were angled at 45º. The sides were armored by 27 mm steel, 40 mm space and 27 mm steel (27+50+27). The rear side and rear plates were armored by 27 mm plates. The turret top was armored with a 20 mm thick steel plate, while the removeable top plate to pull out the 105 mm gun was protected by about 13 mm.
Armament
The Tamoyo 2 was armed with a Brazilian copy of the GIAT 90 mm CS Super 90 F4 gun. The Brazilian designation for this gun was Can 90 mm 76/90M32 BR3. This gun was an L/52 gun that could handle a pressure of 2,100 bars and had a recoil stroke of 550 mm (21.6 inch). The gun had a recoil force of 44 kN for standard ammunition and 88 kN for APFSDS ammunition. The BR3 gun used APFSDS as its main anti-armor round due to the 52 caliber length and the incorporation of the single baffle muzzle brake, which allowed the firing of APFSDS projectiles. The BR3 would have had 5 types of ammunition available to it: canister, high explosive, high explosive anti-tank, smoke, and armor-piercing fin stabilized discarding sabot rounds.
Round
Capability
Effective range
Velocity
Weight
APFSDS (Armor Piercing Fin Stabilised Discarding Sabot)
Heavy
NATO Single Plate: Point blank (60º 150 mm)
NATO Triple Plate: 600 m
(65º 10 mm, 25 mm, 80 mm to simulate side skirt, road wheel and side hull respectively)Medium
NATO Single plate: 1,200 m (60º 130 mm)
NATO Triple plate: 1,600 m
(65º 10 mm, 25 mm, 60 mm)
1,650 meters (1,804 yards)
1,275 m/s
2.33 kg dart (5.1 lbs)
HEAT (High Explosive Anti Tank)
130 mm (5.1 inch) at 60º from vertical or 350 mm (13.8 inch) flat at any range.
1,100 meters (1,200 yards)
950 m/s
3.65 kg (8 lbs)
HE (High Explosive)
Lethal radius of 15 meters (16 yards)
925 meters (1,000 yards)
6,900 meters (7,545 yards) for long range HE
750 m/s
(700 m/s for long range HE)
5.28 kg (11.6 lbs)
Canister
Training projectile
200 meters (218 yards)
750 m/s
5.28 kg (11.6 lbs)
White Phosphorus – Smoke
Smoke round
925 meters (1,000 yards)
750 m/s
5.4 kg (11.9 lbs)
The Tamoyo had stowage for 68 rounds of 90 mm ammunition. In addition, it was armed with a coaxial 12.7 mm machine gun and could be armed with a 7.62 mm machine gun on the commander’s station for anti-air purposes, with 500 and 3,000 rounds of ammunition respectively. The Tamoyo 1 also had 8 smoke discharges, of which four were installed on each side of the front turret. The turret had an electric and manual traverse system and the gun had an elevation and depression of 18 and -6 degrees respectively.
The fire control system includes a computer with unknown usage, most likely to better integrate the usage of day/night sights and the laser rangefinder which were used by the Tamoyo 1. This could potentially also mean a lead calculator and the integration of a meteorological system, although these were features of the Tamoyo 3, which used a much more advanced fire control system. The electric fire-control system, turret rotation and gun elevation were produced by Themag Engenharia and the Universidade de São Paulo (University of São Paulo). It seems that the Tamoyo 2 did not have a stabilized gun (sources are not very clear), while the Tamoyo 3 did incorporate these features.
The Tamoyo 2-105 offered both a 105 mm gun and a much more advanced fire-control system. The Tamoyo used a 105 mm L7 LRF (Low Recoil Force) gun. The low recoil force enabled the Tamoyo to mount a high-velocity gun while preventing any negative effects the recoil might have due to the lightweight of the Tamoyo. The 105 mm Tamoyo also offered a much more advanced Fire-Control System compared to the original 90 mm Tamoyo. It had a fully electric drive system and was fully stabilized, with a hunter-killer system, passive day-night vision, laser rangefinder, and a more advanced firing computer. The FCS had a meteorological sensor, a ammunition temperature sensor, munition drop calculator, and an ammunition selector.
The 105 mm L7 would offer a large range of ammunition to the Tamoyos. A few rounds would be mentioned here which appear in sources.
Round
Capability
Effective range
Velocity
Weight
APFSDS L64 (Armor Piercing Fin Stabilised Discarding Sabot)
170 mm at 60º from vertical at 2,000 meters.
2,500 meters
(2734 yards)
1490 m/s
3.59 kg dart (Tungsten, 28 mm diameter)
APDS L52 (Armor Piercing Discarding Sabot)
240 mm flat from vertical at 2,000 meters.
210 mm at 30º from vertical at 2,000 meters.
120 mm at 60º from vertical at 2,000 meters.
2,500 meters
(2,734 yards)
1426 m/s
6.48 kg projectile
HEAT M456 (High Explosive Anti Tank)
360 mm (13.8 inch) at 30º at any range.
2,500 meters (2734 yards)
1174 m/s
10.25 kg (8 lbs)
HESH (High Explosive Squash Head)
A multipurpose round for both anti-armor and anti-personnel purposes. Also used as High Explosive.
–
732 m/s
11.26 kg (11.6 lbs)
White Phosphorus – Smoke
Smoke round
–
260 m/s
19.6 kg (11.9 lbs)
The turret had an electric elevation and traverse system and offered a gun elevation of 15º and a gun depression of -6º. It had a maximum elevation speed of 266 mils/s or about 15º per second and a maximum traverse speed of 622 mils/s per about 35º per second. It was further armed with a coaxial and turret top 7.62 FN MAG machine gun, although the coaxial machine gun could be replaced with a .50 as an option. The Tamoyo 3 stored 42 rounds of 105 mm ammunition and at least 4000 rounds of 7.62 ammunition. A searchlight was installed coaxial to the coaxial machine gun.
Other Systems
The electrics were powered by a main engine-driven main generator, which produced 24 volts. In addition, four 12 volt batteries were available in order to use the vehicle without starting the main engine. The Tamoyo could receive an NBC system and a heater as optional equipment. The NBC system could be mounted on the already existing ventilation system.
The vehicle used a radio which was also integrated with the M41C and the X1A2 tanks, capable of receiving the EB 11-204D and simpler frequencies. The radio also worked with AN/PRC-84 GY and AN/PRC-88 GY frequencies. The Tamoyo also had an intercom system for the entire crew, which could be linked to the radios. The Tamoyo is said to have had a bilge pump as well, which might have been optional.
Fate
The Tamoyo 2 would never be trialled by the Army and was effectively cancelled with the rejection of the Tamoyo 1. It seems that, after the Osorio trials of 1986, the Brazilian Army realised they wanted a tank like the Osorio and not the Tamoyo they initially thought they wanted. As a result, the trials for the Tamoyo 1 were delayed and, in 1988, it would be rejected due to bad mobility performance.
These mobility characteristics could mainly be blamed on the conception of the Tamoyo program from the very beginning by the Army, and not by Bernardini. The Army specifically wanted a vehicle with as much interchangeability with the M41 as possible. This effectively limited the hp/ton ratio of the Tamoyo 1, as it was limited to a 500 hp engine. Although the Tamoyo 2 did offer a higher horsepower potential, it would not be enough to pass the new Brazilian requirements.
By 1991, the construction of 2 Tamoyo 1’s and the Tamoyo 2 had cost a little under 2.1 million US dollars (4.2 US Dollars in 2021). This suggests that a Tamoyo 2 would have cost about 700,000 US Dollars (1.4 million US Dollars in 2021) to manufacture a piece during the prototype stages. The cost per vehicle might have been less if the vehicle had reached serial production.
In 1991, the Tamoyo 3 was trialed by the Army instead. The Tamoyo 3 would also face a brick wall, as the Army staff was split regarding the Tamoyo 3. One side was in favor of the Army sharing the costs of the evaluation of the Tamoyo 3, while the other side wanted to terminate the entire Tamoyo projects and that the costs of the evaluation should fall solely on Bernardini.
This was because the Tamoyo 3 was classified as a foreign vehicle instead of an indigenous design, since it used a great deal of components which were not yet produced in Brazil. These components included the L7 cannon, automatic fire extinguishing sensors, and the fire control system, among others. The Army definitively canceled the entire Tamoyo project on July 24th 1991. With this decision, Brazil effectively shut down any possibility of an indigenous designed and manufactured main battle tank for the Army.
Tamoyo 3
With the rejection and cancellation of the Tamoyo project in 1991, the Tamoyo 2 seems to have been scrapped. The engine did survive and remained with Bernardini until their bankruptcy in 2001. The engine was put up for sale together with the Tamoyo 3 prototype. It is unknown if the collector who bought the Tamoyo 3 also bought the DSI-14 engine of the Tamoyo 2.
Conclusion
The Tamoyo 2 was an attempt by Bernardini to offer a more modern and capable version of the Tamoyo 1. Although the Brazilian Army did not necessarily ask for it, it did agree with the development of the Tamoyo 2. It might be that the Brazilian Army did see potential in the better transmission, or just did not mind that one of the Tamoyo’s they wanted would receive a more modern transmission. The usage of such a new transmission would come with the benefit of getting more experience with modern components and enable more options for the Tamoyo 3 meant for export.
In the end, it seems that the Tamoyo 2 was a victim of its own conception and would only serve as a test bench. The limited horsepower which the transmission could handle was not in accordance with the new requirements set by the Brazilian Army after they trialled the Osorio in 1986. As such, the Tamoyo 2 was left in the cold and the Tamoyo 1 and 2 projects abruptly came to an end after 9 years of development for the Army and by the Army.
Specifications (MB-3 Tamoyo 2)
Dimensions (L-W-H)
With 90 mm turret
6.5 meters (21.3 feet) and 8.77 meters (28.8 feet) with the gun pointing forward, 3.22 meters (10.6 feet), 2.2 meters (7.2 feet) to turret top and 2.5 meters (8.2 feet) in total.With 105 mm turret
6.5 meters (21.3 feet) and 8.9 meters (29.2 feet) with the gun pointing forward, 3.22 meters (10.6 feet), 2.35 meters (7.7 feet) to turret top and 2.5 meters (8.2 feet) in total.
Total weight
With 90 mm turret
28 tonnes empty, 30 tonnes combat-loaded (30.9 US tons, 33 US tons)With 105 mm turret
29 tonnes empty, 31 tonnes combat-loaded (32 US Tons, 34 US tons)
Crew
4 (commander, driver, gunner, loader)
Propulsion
DSI-14 turbocharged V8 500 hp diesel engine
Suspension
Torsion bar
Speed (road)
67 km/h (40 m/h)
Armament
90 mm BR3 (temporary 105 mm L7 LRF)
Coaxial .50 caliber MG HB M2
Anti-Air 7.62 mm mg
Armor (with 90 mm turret)
Hull
Front (Upper Glacis) 40 mm at 60º (1.6 inch)
Front (Lower Glacis) 40 mm at 45º (1.6 inch)
Sides 19 mm at 0º (0.75 inch)
Rear 25 mm
Top 12.7 mm at 90º
(0.5 inch) Turret
See description
Produced
1
Sources
Blindados no Brasil – Expedito Carlos Stephani Bastos
Bernardini MB-3 Tamoyo – Expedito Carlos Stephani Bastos
M-41 Walker Bulldog no Exército Brasileiro – Expedito Carlos Stephani Bastos
M-113 no Brasil – Expedito Carlos Stephani Bastos
Jane’s armour and artillery 1985-86
Brazilian Stuart – M3, M3A1, X1, X1A2 and their derivatives – Hélio Higuchi, Paulo Roberto Bastos Jr., and Reginaldo Bacchi
Moto-Peças brochure
Memoir of Flavio Bernardini
Author’s collection
Bernardini compra fábrica da Thyssen – O Globo, archived by Arquivo Ana Lagôa
The Centro de Instrução de Blindados
Tecnologia & Defesa magazines with courtesy of Bruno ”BHmaster”
With Expedito Carlos Stephani Bastos, Expert in Brazilian Armoured Vehicles
With Paulo Roberto Bastos Jr., Expert in Brazilian Armoured Vehicles
With Adriano Santiago Garcia, A Captain of the Brazilian Army and ex-company commander on the Leopard 1
Federative Republic of Brazil (1984-1991)
Medium Tank – 4 Built + 1 Mock-up
The development of a national tank in Brazil started as early as 1969, with the founding of the Centro de Pesquisa e Desenvolvimento de Blindados (CPDB) (English: Centre for the Research and Development of Tanks). The CPDB studied the possibilities of locally produced tanks and initiated its first project in the early 1970s, which would become the X1 light tank family.
Bernardini, the company which developed the X1 family together with the Parque Regional de Motomecanização da 2a Região Militar (PqRMM/2) (English: Regional Motomecanization Park of the 2nd Military Region), went on to develop the M41B. The successful development of the M41B gave Bernardini enough confidence and experience to initiate the development of a national tank together with the Army.
Before Engesa’s Osório rose to prominence, Bernardini initiated the development of their national tank in the late 70s. This project was called the MB-3 Tamoyo. The MB-3 Tamoyo started off as an improved version of the M41 Walker Bulldog, sharing as many components as possible to ease logistics, but would reach its apex as the Tamoyo 3, which could be classified as a full-fledged Main Battle Tank in South America. It is important to note that the Tamoyo’s were not conversions from the M41, but completely new designs.
Although the Tamoyo, and especially the Tamoyo 3, had much potential and fitted the initial requirements of the Brazilian Army, they were not selected and were overshadowed by the Osório. The Tamoyo’s were tested very late in comparison to the Osório, and it seems that this delay caused the Army to realise that they did not want the Tamoyo 1. They wanted a main Battle Tank like the Osório and the Tamoyo 3. In the end, the Tamoyo would end up as the most realistic tank for Brazil, but would never come to fruition.
Designations
The Tamoyo had various designations to denote the stages of the project. The first stage of the Tamoyo was designated X-30, with the X standing for prototype and the 30 for its 30 tonnes weight. This designation was used until the first working prototype of the Tamoyo 1 was delivered in May 1984.
There is also the VBC CC XMB3 (Viatura Blindada de Combate – Carro Combate – X Médio Bernardini-3, Armored Fighting Vehicle – Combat Car – X Medium Bernardini-3) designation, which is seen at a sign accompanying the mock-up of the Tamoyo and is written on the sides of most variants of the Tamoyo as well. The X again denominates the prototype phase of the vehicle, and the MB refers to the designer and manufacturer of the vehicle. The 3 denotes that this is the third vehicle Bernardini ‘’designed’’, with the 1 being the X1, the X1A1 being the 1A, the X1A2 being the 2, and the X1A2 second production batch being known as 2A. What is interesting is that the M41B and M41C projects of Bernardini were not counted in the MB-X designation system of the company.
The earliest mention of the Tamoyo designation was recorded in November 1983, named to honor the Tamoyo Confederation of the Tupinambá people. The Tamoyo Confederation was an alliance of various indigenous tribes of Brazil in response against the slavery and murder inflicted on the Tupinambá tribes by the Portuguese discoverers and colonizers. The Tupinambá people fought against the Portuguese from 1554 to 1575. A peace treaty between the two warring parties was signed in 1563, although the fighting did not completely end until 1567, after the Portuguese colonists were sufficiently strengthened to tip the scales completely in their favor. The Tamoyo Confederation was effectively wiped out by 1575. Tamoyo means grandfather or ancestor in the Tupi language.
It seems that after the first Tamoyo prototype was built on May 7th 1984, that the Tamoyo received its official designation MB-3 Tamoyo. The MB-3 Tamoyo has 3 main sub designations, these are Tamoyo I, Tamoyo II, and Tamoyo III (named Tamoyo 1, 2, and 3 in this article for ease of reading). The Tamoyo 1 refers to the Tamoyo meant for the Brazilian Army, armed with a 90 mm BR3 gun, DSI-14 500 hp engine and a CD-500 transmission. The Tamoyo 2 was exactly the same as the Tamoyo 1, except that it used a modern HMPT-500 transmission. The Tamoyo 3 refers to the export version, which was a much-upgraded version of the original Tamoyo. The Tamoyo 3 was armed with a 105 mm L7, had an 8V-92TA 736 hp engine, a CD-850 transmission, and was armored with composite armor instead of only steel. The Tamoyo 3 would eventually be proposed to the Brazilian Army as well in 1991, a year after the failure of the EE-T1 Osório.
The 8 vehicles which were planned, and the first prototype received individual designations as well. These designations went from P0 to P8 and had sub-designations regarding their models as well. The first working prototype was designated P0 and held the model designation TI-1, where TI refers to Tamoyo 1 and the 1 refers to the first Tamoyo 1 vehicle. There were also three support vehicles envisioned, which were a bulldozer, bridgelayer, and engineering vehicle. These are denoted by VBE (Viatura Blindada Especial, Special Armored Vehicle)
The Tamoyo TI-1, TI-2, TI-3, and TI-4 will be the four main vehicles of interest in this article. These are all Tamoyo 1s with slight variations between them, from the location of pioneer tools, to the mounting of a Laser Range Finder. It is important to note that the overall development of all the different Tamoyos is intertwined. Thus, there are a reasonable amount of references to other Tamoyo versions in this article. Please refer to this table of designations to prevent possible confusion of all the various designations that distinguish the individual vehicles from each other.
Tamoyo Type
Prototype
Model designation
Tamoyo 1
P0
TI-1
Tamoyo 1
P1
TI-2
Tamoyo 2
P2
TII
Tamoyo 1
P3
TI-3
Tamoyo 3
P4
TIII
Tamoyo 1
P5
TI-4
Engineering Tamoyo
P6
VBE Bulldozer
Engineering Tamoyo
P7
VBE Bridge Layer
Engineering Tamoyo
P8
VBE Engineering
Genesis
The development of the Tamoyo can be traced back to the X1. The X1 was a modernization project of the M3 Stuart, carried out by the PqRMM/2 team, Biselli and Bernardini. Bernardini was responsible for the turret and the suspension. After the X1, the team would try to fix some of the vehicle’s flaws by designing the X1A1. The X1A1 was effectively a lengthened X1 tank with a hybrid M4 Sherman/18-ton M4 Tractor suspension and a redesigned turret. The X1A1 project ended up breaking the X1 even more and was canceled. Biselli left the X1 project around this time in the mid-1970s, making Bernardini fully responsible for the X1 family of vehicles and all future tank development.
The X1A1 was canceled, as it was too much effort to fix the old base M3 Stuart. The engineers would have needed to widen the Stuart hull, and would still retain issues inherent to the age of the hull. It was decided to develop a new tank, which was designated X-15. The X-15 would be the first fully designed tank in Brazil, which resulted in the X1A2 tank.
The X1A2 used the same suspension and a further developed turret of the X1A1. The X1A2 hull was wider than the X1A1, fixing the issues of the X1A1. The tank used several new components, of which the most notable were the EC-90 low-pressure gun, and the CD-500 transmission. Both the CD-500 transmission and the design concepts of the X1A2 turret were later incorporated in the Tamoyo 1 project. The X1A2 was Brazil’s first and so far only tank which was fully designed in Brazil and used in active service. The X1 family of projects and the X1A2 gave the engineers of Bernardini the experience and confidence to start developing the M41 Walker Bulldog upgrades.
The M41 Projects
With the success of the X1 family project, Bernardini and the Brazilian Army initiated the development of the M41 upgrade programs. This started much the same way as the other projects of the Brazilian Army. The first step was to remotorize the M41 with a locally produced Scania DS-14 V8 350 hp diesel engine. This upgrade was designated as M41B and included various other smaller upgrades beside the engine. The first M41B was built in 1978.
Bernardini had now gained enough confidence to start developing their own tank. A year later, Bernardini started the development of what would become the Tamoyo 1. Bernardini also went on to further develop the M41B upgrade into the M41C, parallel to the development of the Tamoyo. The first M41C was developed around 1980 and mounted the same engine, a turret with additional spaced armor, a rebored 90 mm low-pressure gun, and a multitude of other minor upgrades and upgrade packages. A single M41C would end up as a testbed for the high-pressure 90 mm armament of the Tamoyo 1.
The German proposals of 1976-1977
Beside the projects of Bernadini, the Germans also seemed to have some influence during the concept stages of the Tamoyo 1 development. Previous military relations between the US and Brazil had declined and, in 1977, Brazil and the US broke off their military agreements. This break was caused by the German-Brazilian nuclear energy cooperation and the lost usefulness of the military agreement for Brazil. Germany tried to capitalize on the declining relations by proposing a range of vehicles to the Brazilian Army.
Two of these vehicles were tanks, of which one was essentially a TAM tank for Brazil, and the other a 35-tonne tank. The TAM was still being designed by the Germans and Argentinians around this time, and the first prototype of the TAM was completed in September 1976 for Argentina. The 35 tonnes tank had a much more conventional layout compared to the TAM, as it did not have an engine located in the front of the vehicle. Brazil did not buy either of these tanks, preferring to rely on their own industry to build a new tank.
It is thought that the proposal by the Germans and the appearance of the TAM in Argentina influenced the initial concept stages and design requests by the Brazilian Army for the Tamoyo project. If this influence came directly from the German proposals or from the usage of the TAM in Argentina is unclear. Both factors probably contributed in varying importance to the requests of the Brazilian Army.
Bernardini
Bernardini SA Indústria e Comércio was founded by Italian immigrants in 1912. They manufactured steel safes, armored doors, and value transport vehicles. In the 1960s, Bernardini would come in contact with the Armed Forces by building the bodies for trucks for both the Brazilian Marine Corps and the Army. In 1972, the company was asked by the Army to participate in the PqRMM/2 project to develop the X1 tank with Biselli.
Bernardini’s participation in the X1 project solidified their position as the company responsible for building tanks in Brazil. The Brazilian defense industry was founded with a gentleman’s agreement to prevent competition between the various companies involved. Engesa initially focused on wheeled vehicles, for example. The main difference between the two companies was that Engesa was very much export-driven, while Bernardini carried out projects according to the needs of the Brazilian Army and then looked at potential export possibilities. In a way, Bernardini was much more dependent on the Army, while Engesa was dependent on selling their equipment abroad.
This difference in policy can be seen in the total amount of exports of Bernardini compared to the rest of the Brazilian defense industry. Bernardini exported 5% of their total production compared to 80 to 95% of the rest of the Brazilian defence industry. Although this made Bernardini less susceptible to failed export bids, it did make Bernardini dependent on an Army with an ever-tight budget.
The X-30
The Brazilian Army staff was worried about the Argentinian acquisition of the TAM tank. The TAM effectively outclassed any vehicle the Brazilian Army owned in firepower, armor, and in the mobility department. In comparison, the most advanced tank of the Brazilian Army was the M41 Walker Bulldog, which was still in the initial stages of modernization. As a result, the Army staff decided that Brazil needed a new tank.
The specifications of the new tank were released around 1979 by the CTEx (Centro Tecnológico do Exército (CTEx, Army Technology Center), which was led by Division General Argus Fagundes Ourique Moreira. Division General Argus Moreira and the CTEx were responsible for the acquisition of funds from the Army for the project, and to give input in the selection of components, design, and companies working on the new tank. The CTEx effectively participated in this project to ensure that the Army would receive a feasible Carro de Combate Nacional Médio (National Medium Combat Car/tank, the Brazilian army calls all their tanks combat cars). This basically meant that they would get a tank, capable of dealing with the TAM and with a favorable price tag for the Army. For this project, the CTEx selected Bernardini as its partner.
A range of requirements for the new tank were put forward by the CTEx for both an indigenous and export version. What is interesting, is that the Army seems to not have completely abided by these requirements when they accepted the Tamoyo projects. The Army wanted a tank that weighed 30 tonnes (33 US tons, although this later seems to have increased to 36 tonnes (39.7 US tons) and was 3.2 meters (10.5 feet) wide for rail transport (same width as the Leopard 1), an operational range of around 500 km (310 miles), a ground pressure of roughly 0.7 kg/cm2 (10 lbs/in2), a high percentage of locally-produced components as possible, and have as many commonality of parts as possible with the M41 and the Charrua for logistical reasons. The Charrua was a locally designed tracked troop transport that was meant to replace the M113.
In addition, the vehicle had to use a conventional layout, a turret with 3 crewmen (there was no interest in autoloading systems), the national vehicle was to be armed with a 105 mm gun, while the export vehicle was to be armed with a 120 mm gun, a stabilized gun, day/night sights, armor that should provide a high level of protection, diesel engines which gave the vehicles good power to weight ratios, and a fire extinguishing system.
As an interesting bit of information, although mainly for the Tamoyo 3, Bernadini visited Israel a number of times for consultation by General Talik Tal, the mastermind of the Merkava tank. In addition, Bernardini also hired General Natke Nir (sometimes referred to as Natan Nir), who served as a Colonel during the Yom Kippur War, for 6 months as a consultant for the design of armored vehicles. Natke Nir is credited by Flavio Bernardini for introducing spaced and composite armor concepts, improved protection against explosions, ammunition compartmentalization, mine protection, and the employment of tanks in combat situations. Although these consultancies were mainly focused for the Tamoyo 3, it would not be surprising if some concepts were or would eventually be carried over to the Tamoyo 1 as well.
How many Tamoyos did the Army want?
It is unknown how many Tamoyo’s the Army intended to acquire from Bernardini. A couple of estimations can be made to give some idea of the planned Tamoyo’s to be fielded by the Army. The first number is based on the German proposal of the TAM tank for Brazil, which was for at least 300 vehicles. This number also appears in other estimations of how many Osório’s the Army would potentially buy, which ranged from 70 to 300 Osório’s.
Another estimation can be made by basing it on the number of M41C’s Brazil operated at the time, and on the number of Leopard 1’s Brazil is operating today. 323 M41C’s were built by Bernardini for the Army. Although the Tamoyo 1 was meant to operate besides the M41C, it is quite likely that the M41C’s would be gradually phased out as more Tamoyo’s were delivered. This for example happened when the Army bought 378 Leopard 1’s in total. In an issue of International Defense Review, it is stated that the army has a requirement of 300-400 vehicles.
Although the exact number is unknown, both Brazilian and foreign sources, and previous and later events seem to suggest a number of around 300 to 400 vehicles. This is a sizable number compared to the 231 TAMs operated by the Argentinian Army.
The X-30 TAM
Division General Argus Moreira initially requested a tank with a front-mounted engine and rear turret, like the TAM. The tank and the project were designated X-30 (X for prototype and 30 for 30 tonnes (33 US tons)), and the first concept art was released to the public in the newspaper O Estado de São Paulo on May 27th 1979. The article practically presents an improved copy of the TAM, although some of the combined requirements seem to have been somewhat unrealistic when one considers the TAM specifications. The new Brazilian X-30 tank was presented as a 30-tonne tank, armed with a 120 mm cannon, telemetric laser finder, a range of 600 km (370 miles), armor up to 70 mm (2.75 inch), NBC system, fire-extinguishing systems, 4 crewmen, dual controls, and heat-treated armor angled at 20 to 50 degrees. It was also supposed to be able to mount Brazilian copies of the Roland Surface-to-Air Missile system, although Brazil would never manage to successfully copy the SAM system.
To put these specifications in perspective, the TAM weighed 30.5 tonnes (33.6 US tons), had a 105 mm cannon, 590 km (366 miles) operational range, armor up to 50 mm (2 inch), a crew of four, and armor angled from 32 to 75 degrees. The amount of road wheels of the X-30 is also exactly the same as on the TAM, suggesting more or less equal dimensions as well. The interesting part is that the X-30 effectively promised a better gun and better armor, while weighing as much as the TAM.
This presentation of the X-30 seems more of a propaganda article with the technician, who gave the information to the journalist, sketching a very impressive and capable vehicle that the Brazilian Army would most likely not have been able to afford in the first place. The construction of a steel mock-up that used the front-engine configuration was already underway, but would never be finalized. The TAM-inspired design was very short-lived, as Bernardini and the CTEx opted for a traditional lay-out in less than 6 months.
The actual design of the X-30 TAM concept appears in an undated video of Bernardini where a show briefly shows the design. The design resembles the sketch from the newspaper with some changes. The smoke launchers are located on the front of the turret, there is no structure on the sides of the turret for the commander and loader hatches, the vehicle has an extra structure on the top of the hull which can be seen by the lower placed driver sights, and the vehicle has 3 return rollers instead of 4. The armament shown in the design of Bernardini is unknown, but is thought to be a 105 mm gun. The sketch does not yet take the engine placement into account, although this might have to do with the drawing not being finished. The construction of a steel mock-up that used the front-engine configuration was already underway, but would never be finalized. The TAM-inspired design was very short-lived, as Bernardini and the CTEx opted for a traditional layout in less than 6 months.
The Traditional X-30
The front-mounted engine design was discussed with Bernardini, considering weight balancing, armor distribution, and the moments of forces and inertias. In the end, Bernardini and the Army decided to go for a traditional layout with a rear-mounted engine. A contract between the Army and Bernardini was signed and the development of a mock-up and prototype was initiated. The switch to the traditional design happened anywhere between May 1979 and January 1980.
Transmissions and Engine
The first step in developing the new tank was the selection of a transmission. The Brazilian Army wished for the CD-500-3 transmission to ensure interchangeability with the M41 Walker Bulldog fleet and because of an envisioned M113 replacement. The M113 replacement was named Charrua and in development by Moto-Peças. The project would never go further than the prototype phase. Considering the CD-500 transmission was no longer in production, Bernardini thought that it could obtain the designs from General Motors Allison and start producing the CD-500 transmission and spare parts in Brazil.
Bernardini decided that it would be a wise decision to offer the X-30 with a more modern transmission as well. Bernardini started negotiations with General Electric to obtain the HMPT-500-3 transmission, as used on the M2 Bradley. The advantage of the HMPT-500 was that it would allow the use of more powerful engines up to 600 hp, and thus give the eventual Tamoyo more upgrade potential. The HMPT-500 Tamoyo would eventually be designated as Tamoyo 2 after Bernardini had requested permission for the funds to develop it in June 1984.
With the selection of the CD-500 and HMPT-500 transmission, Bernardini was effectively bound to the Scania DSI-14 V8 500 hp diesel engine. This was not necessarily bad regarding the logistical structure of the Brazilian Army, considering the interchangeability with the M41s, but it would limit the power to weight ratios of the Tamoyos severely and even cause significant issues in the end.
Arming the Tamoyo
The process of arming the Tamoyo began parallel to the process of rearming the M41C. Since the 76 mm ammunition was not being produced anymore by the United States, Bernardini and the Army decided that rearming the M41C was the way to go. The Army did some research in the possibilities on how to rearm the M41C, and after they tested a rearmed M41B with an EC-90 90 mm low pressure gun of the Cascavel, the Army decided that reboring the original guns to 90 mm would be the most affordable decision.
As such, the first batch of 76 mm guns were rebored at Engesa to have the same rifling as the EC-90 and were even cut down to the same caliber length as the EC-90 (later, they would discover that cutting the barrels from the original 4.5 meters (14.8 feet) to 3.6 (11.8 feet) did not provide any advantages). Both these cannons used the same low-pressure ammo as the EE-9 Cascavel and were designated ‘Can 90mm 76/90M32 BR1’ (shortened barrel) and ‘Can 90mm 76/90M32 BR2’ (long barrel).
Parallel to the development of the BR1 and BR2 guns, the Brazilian Army and the CTEx also looked into arming the M41C with a GIAT 90 CS Super Gun, also known as the Super 90 of 90 mm F4. The Super 90 had a longer barrel than the EE-9 Cascavel’s EC-90 guns, which made them more fitting for firing kinetic ammunition. The low-pressure EC-90, the BR1, and the BR2 relied on HEAT ammunition to take out their opponents due to the lacking muzzle velocity in order to lessen the recoil of the guns. The Super 90 used a single baffle muzzle brake which allowed the gun to fire APFSDS ammunition.
A single Super 90 gun was purchased, together with about a thousand APFSDS rounds. The CTEx proceeded to test the gun and to take apart the APFSDS round in order to develop their own APFSDS round for local production. During these tests, the Brazilian Army determined that the Super 90 could also be mounted on the M41 Walker Bulldog. As a result, a single M41C mounted the Super 90 gun, potentially to one day arm the entire M41C fleet of Brazil or simply as an export option for Bernardini. In the end, this single M41C would be nothing more than a testbed for the Super 90 gun and ammunition.
The Brazilians copied the Super 90 gun and designated it ‘Can 90mm 76/90M32 BR3’. As this designation suggests, these guns were and could be converted from the 76 mm gun of the M41 Walker Bulldog. The BR3 gun was selected by the Army to arm the Tamoyo 1 and 2 tanks to take on the TAM tanks of Argentina. This decision makes it clear that the Brazilian Army originally did not intend to operate a tank with a 105 mm gun like the TAM, mainly due to budget constraints, but probably realized with the EE-T1 Osorio that the 105 mm was the new standard.
Interestingly however, when the author visited one of the Tamoyo 1 vehicles himself in Brazil, it turned out that the Barrel itself seems to have come from an M41 and was likely a rebored 76 mm cannon. This is because the barrel itself had WVT Arsenal stamped on, suggesting Watervliet Arsenal in the United States, and barrel number 32687. This was the only marking present on the entire cannon, suggesting the breech was altered but just not serialized.
Working towards a Mock-Up
From this point on, development becomes a bit vague. This mainly has to do with a lack of dates on when concept arts were made and when the first mock-up was actually built. There are about 3 concepts that are estimated to have been made before the mock-up was made. The writer proposes a certain timeline on the order of the designed concepts. This proposal is not confirmed by hard evidence or dates, but is speculation based on design steps taken in comparison with either previously developed vehicles or on how much the design has been worked out in the details. The date when the mock-up was finished is unknown, but can be estimated in between 1980 and 1984.
Jane’s Concept
A concept sketch of the X-30 was presented in the first issue of Jane’s 1980 International Defence Review. A description of the concept was given as well, stating that the drawing shows Bernardini’s project for a 30-tonne medium tank, designated X-30, which was currently in the definition phase. It would have a Diesel engine of 520 to 745 kW (700 to 1000 hp), an automatic transmission, have a range of 500 km (310 miles) and a ground pressure of about 0.7 kg/cm2 (10 lbs/in2), of which the last two specifications were based on the Brazilian Army’s requirements. According to the Brazilian correspondent, it was to be armed with either a 105 mm or 120 mm gun, although the current concept shows a Cockerill 90 mm gun. In addition, it is stated that the first prototype was estimated to be ready for trials in two years.
This concept is estimated to be the first concept for two reasons. The first is the date when this concept was released (January 1980), which means that this concept was made about 6 months after the first TAM-inspired concept. The second reason is that this concept is nothing more than a mash-up of two tanks previously designed by Bernardini.
Jane’s concept mixes an enlarged X1A2 turret with the hull of an M41B. The concept derives in two major ways from the two vehicles it is based on. The first is that the hull is longer, as it has 6 road wheels instead of 5 on the M41, and the second is that the main gun looks like a lengthened EC-90 gun of the X1A2 with an added bore evacuator. Another difference is the driver’s hatch, which does not correspond with either vehicle.
It seems that this concept was already based on the specifications of the export version of the Tamoyo, which was the Tamoyo 3. There are a few interesting statements though. The first is the engine power, which is denominated in kW instead of hp. This was probably some kind of mix-up between units, as 520-745 kW translates to 700-1000 hp, considering the given specifications are very close to the horsepower values which Bernardini presented for the DSI-14 and 8V-92TA engines.
Overall, this concept seems to be mainly suggesting a potential export version of the X-30 instead of the X-30 for the Brazilian Army. This concept is potentially one of the first drawings of the X-30 in a traditional layout. The design itself is somewhat unimaginative, considering it’s a mash-up of the X1A2 and the M41B, and the specifications are somewhat questionable as well.
An Artistic Interpretation
This concept was released in the press and abroad after the switch to the traditional layout. This concept dates back to at least April 1980, as the sketch is shown on the cover of Brasil Defesa – Os Blindados do Brasil. In this sketch, the X1A2 turret is a little bit altered, but uses a redesigned hull that resembles the final hull design much closer.
This concept retains a redesigned variant of the X1A2 turret, but the hull in this concept is different. The hull shares much fewer design features with the original M41 or the Brazilian M41B and M41C. The engine deck looks more like a main battle tank and resembles the Tamoyos which were built. The tracks of the concept do show a very clear resemblance to the M41 tracks. The gun on this concept is unknown, but it does seem to resemble a 105 mm gun, although this is pure speculation.
The Tamoyo Maquette
The next design was a wooden mock-up. This design might have been built between the concept sketch phase and the full-scale mock-up production phase, although this is not confirmed. This model is almost identical to the full-scale mock-up. The hull and turret shapes are effectively the same, although the gun is indistinguishable. This design is also the first design that incorporates side skirts.
Unusually, this vehicle has Tamoyo and Selva written on it. If this was done when the wooden model was originally built or if it received a repaint afterward, is unknown. It is not known where Selva comes from, but it might refer to the builder of the mock-up or to jungle, as Selva translates to jungle. This mock-up is preserved at the CTEx.
The Full-Scale Mock-Up
A mock-up of the X-30 was built somewhere in between 1980 and 1984. This mock-up was a full-scale metal model which shared some components of the M41 Walker Bulldog to make production easier. It is important to note that the mock-up and the Tamoyo project as a whole were not lengthened M41s or converted M41s in any way.
The X-30 mock-up used the M41 suspension, Brazilian copies of the T19E3 tracks produced by Novatraçao, and an altered 76 mm gun of the M41 (with a muzzle brake of the Super 90). The design of the previous X-30 mock-up was practically unaltered. The X-30 was, in principle, the shell of the Tamoyo 1 without all the components like smoke launchers, sights, hooks and so on. The X-30 is preserved as a monument at the CTEx.
The Tamoyo 2 Mock-Up?
According to Flavio Bernardini, then one of the CEO’s of Bernardini, Bernardini also produced a mock-up of the Tamoyo 2. Although this is probably true, it does not make much sense. The only difference between the Tamoyo 1 and the Tamoyo 2 is the transmission of the vehicle. The rest of the design remained unchanged in the initial stages.
Even more confusing, the picture of the mock-up is dated August 1983. The lower hull is more or less completed, but the turret is a styrofoam mock-up. This styrofoam mock-up is almost exactly the same as the X-30 mock up except for a few details, like lifting eyes. In addition, the gun presented on the Tamoyo 2 mock-up is a dummy of the 76 mm from the M41. The rear side hull plate does look different from the eventual X-30 mock-up, as the rear part does not widen as gradually.
Another detail that makes this mock-up confusing is that the contract for the development of the Tamoyo 2 was signed in 1984 and not 1983. It is possible that Bernardini proposed this upgrade earlier on, which could explain the existence of the mock-up.
Finally, it is unknown what happened with the Tamoyo 2 mock-up, while the X-30 mock-up was preserved at the CTEx. This makes it impossible to either fully prove or disprove that a Tamoyo 2 mock-up existed. For all we know, it was scrapped, or it was integrated with the current X-30 mock-up preserved at the CTEx.
The writer thus somewhat questions the existence of the Tamoyo 2 mock-up and suggests that it might just be the X-30 mock-up in early stages. This would not be very unlikely, as the contract for the production of the Tamoyo prototypes between the Army and Bernardini was only signed in March 1984. The styrofoam turret suggests that, as of late 1983, no steel mock-up turret was available, and the slight change in the hull design suggests further development in this regard as well. This means that the general design of the hull and turret, and the mock-up itself, would have been finalized in the coming 7 months when the contract was signed for the prototype production in late March 1984.
Considering the mock-up is outfitted with tracks, it is also a possibility that the Tamoyo 2 mock-up was later converted to the Tamoyo 2. But this also seems somewhat unlikely, because it would not make sense to convert the Tamoyo 2 mock-up into the Tamoyo 2, but not do this for the Tamoyo 1 by converting the X-30 mock-up.
The writer cannot definitively prove his theory, and would like to add that he does not want to imply that Flavio Bernardini is wrong, considering Flavio Bernardini was present at the time and involved with the project. The writer implies that the picture might have been labeled incorrectly and that, over the period of 20 to 30 years, the exact details might have been hard to remember. The writer thus questions the logic and practicality of designing a mock-up for basically the same vehicle, and provides an alternative chain of events to what might have happened.
The Tamoyo 1 Has Been Built
The first working prototype was delivered on May 7th, 1984, and received the official designation MB-3 Tamoyo. This Tamoyo was known as the Tamoyo I/1 model and received 0001 as the serial number. Interestingly, while delivered in 1984 for trials, the manufacturing year was stamped as 1985 on the internal identification plate.
The Tamoyo used a high number of locally-produced components, with the suspension, gun, steel for the hull and turret, engine, and the electric turret drive being produced in Brazil. Bernardini specifically selected as many components as possible which could be manufactured in Brazil through license deals or subsidiaries in Brazil itself to make the Tamoyo as indigenous as possible, which included the CD-500 transmission. The prototype was successfully tested by the Army two days after completion in Rio de Janeiro.
Suppliers Tamoyo 1
Country
Company
Component(s)
Brazil
Bernardini
Hull, turret, suspension components, electric turret and elevation drives
Brazil
Themag Engenharia
Electric turret and elevation drives
Brazil
Universidade de São Paulo
Electric turret and elevation drives
Brazil
Eletrometal
Torsion bars
Brazil
Usiminas
Steel
Brazil
Novatracão
Tracks and suspension components
Brazil
D.F. Vasconcellos
Driver’s day sights (unknown if they suppied the driver’s night vision sight
Brazil
Brazilian Army
Funding
Sweden-Brazil
Scania do Brasil
DSI-14 500 hp engine
United States
General Motors Allison
CD-500-3 transmission
United States
Unknown
Turret slewing bearing
Interestingly enough, the CTEx and Bernardini had already signed a contract for the construction of 8 Tamoyo 1s on March 27th, 1984. This might suggest that the full-scale mock-up was finished not too long before March 27th and that the first working Tamoyo 1 prototype might have been built between March 27th and May 1984, although this is more speculation.
As stated, the contract covered 8 vehicles, of which 4 were Tamoyo 1s, 1 was a Tamoyo 2, and 3 were engineering vehicles (Bulldozer, Bridge Layer, and Recovery vehicle). The first working prototype was included in this contract. The Tamoyo 3, meant for export, was logically not included in this contract, although the Army did need to give permission to Bernardini to develop an export version. With the signing of the contract, Bernardini ordered 15 CD-500 transmissions for both the Tamoyo and the Charrua project, of which 5 CD-500’s were passed to Moto-Peças.
Building the Tamoyos
Bernardini had two locations available for the construction of the Tamoyo. The first was located in the Ipiranga district of the city of São Paulo in São Paulo state. This factory had a production floor of about 20,000 m2 and would focus on the production of components for the Tamoyo 1. The second factory was located in the city of Cotia, about 20 km from São Paulo city. This factory was meant to assemble the Tamoyos and produced the armament of the Tamoyo and M41C’s. The Cotia factory was bought from Thyssen in 1984 for an undisclosed amount of money. Bernardini estimated it could produce about 50 Tamoyo 1’s per year with these two factories.
The Cotia factory was equipped with the equipment to manufacture or rebore gun barrels with a length of up to 8 meters/67 calibers in length and a diameter of at least 105 mm. Bernardini could also manufacture cannons with a diameter from 20 to 60 mm and a length of 3 meters/25 calibers in length. In addition, Bernardini had 5 CNC machines available to produce the Tamoyo, which included 3 lathes and 1 milling machine. The company also had forging and further machining equipment, was capable of testing their torsion bars, could test their guns, and could simulate equipment wear. With this equipment, Bernardini would have been able to produce most of the essential components by themselves.
The quality control was supported by the CTEx, which checked the gun barrels and breeches with the help of 3D design on computers. The performance of every individual gun was logged during the manufacturing process and the certification tests.
In total, 3 Tamoyo 1s were finished, while the fourth ended up as an empty ‘shell’, with only the hull and turret being produced. Three out of four Tamoyo 1s still exist to this day and are located at various institutions of the Brazilian Army.
The Tamoyo 1 in Detail
The exact weight of the Tamoyo 1 is a bit uncertain as there is no clear document that specifically mentions the weight of the Tamoyo 1. Two weights do recur in documentation, which are 29 and 30 tonnes (32 and 33 US tons) combat loaded. Considering the prototype was designated as X-30, it is quite likely that the actual combat weight is 30 tonnes. Considering the combat weight of the Tamoyo 3 was 31 tonnes (34 US tons) and the empty weight was 29 tonnes, it is estimated that the Tamoyo 1’s empty weight would be around 28 tonnes (30.9 US tons).
The vehicle had a hull length of 6.5 meters (21.3 feet) and was 8.77 meters (28.8 feet) long with the gun pointing forward. It was 3.22 meters (10.6 feet) wide, and 2.2 meters (7.2 feet) tall to turret top and 2.5 meters (8.2 feet) tall in total. The tank was operated by a four-man crew, consisting of the commander (turret middle right), the gunner (turret front right, in front of the commander), loader (turret middle left), and the driver (front hull left).
Some of the details of the technical desciption have been done based on the interior of a Tamoyo 1 museum piece. As a result, certain details may have been different from when the vehicles were initially constructed considering the Tamoyo 1’s have been neglected for about 20 to 25 years.
Hull
The hull consisted of a welded homogenous steel construction. With the help of Adriano Santiago Garcia, a Captain in the Brazilian Army, ex-company commander on the Brazilian Leopard 1’s, and former instructor at the CIBld (Centro de Instrução de Blindados, Armor instruction center), who knew someone present at the CIBld, the writer has been able to uncover a sizable amount of the armor thickness values of the Tamoyo 1 and 2 by measuring the plate thicknesses, which up to now had not yet been published. The armor is heavier than the M41 Walker Bulldog and was meant to stop 30 mm rounds from the front, and 14.7 mm on all sides.
Tamoyo 1 hull armor
Location
Thickness
Angle from vertical
Effective thickness
Upper front
40 mm (1.6 inch)
65-70
95-117 mm (3.75-4.6 inch)
Lower front
40 mm (1.6 inch)
45
57 mm (2.25 inch)
Sides
19 mm (0.75 inch)
0
19 mm (0.75 inch)
Rear
?
0
?
Top
12.7 mm (0.5 inch)
90
12.7 mm (0.5 inch)
The Tamoyo had a headlight and blackout marker on both sides of the upper front hull, with a siren installed behind the right set of lights. A set of tools was installed, on one version of the Tamoyo, on the right mudguard, although on a different Tamoyo, it seems that the engineers installed something resembling a fire extinguisher on both mudguards instead. This version with the fire extinguisher mounts the tools on the right side of the upper front plate. Two lifting eyes were welded on both sides of the side upper front plates as well. In the middle of the upper front plate, in between the sets of lights, were mounting points for a set of spare tracks.
The driver was situated on the left side of the upper front plate, and had 3 vision blocks available. The driver’s hatch was a rotating hatch and the driver also had access to a hull escape hatch. 36 rounds of 90 mm ammunition were stored on the front right of the hull, next to the driver in the museum piece.
The driver had access to a seat and used a steering wheel to steer the vehicle and pedals to throttle and brake. The gear shift for the CD-500 transmission was located to the right allongside the dashboard. The dashboard included information like fuel level, temperatures, speed, but also switches for lights.
The hull side provided mounting points for the installation of side skirts, which consisted of 4 sets of skirts on each side. The early versions of the side skirts were made from steel, but would later incorporate materials like rubber and aramid fibers to improve the effectiveness against certain projectiles.
The Tamoyo has two rear lights on the rear hull plate, and a towing hook on the lower rear plate. In addition to the towing hook, two brackets were installed on this plate and on the lower front plate as well.
Mobility
The Tamoyo 1 was powered by a DSI-14 turbocharged V8 500 hp diesel engine. This liquid-cooled intercooler engine provided 500 hp and 1700 Nm (1250 ft-lbs) at 2100 rpm. This engine gave the Tamoyo a power-to-weight ratio of 16.6 hp/ton. The Tamoyo 1 used a General Motors CD-500-3 cross-drive transmission, which had 2 gears forward and 1 for reverse. Combined, this powerpack gave the Tamoyo a top speed of 67 km/h (40 m/h) on level roads. It had a fuel capacity of 700 liters (185 US gallons) which gave it a range of approximately 550 km (340 miles).
The Tamoyo used a torsion bar suspension with 6 road wheels and 3 return rollers on each side. It had 3 additional shock absorbers installed, with 2 mounted on the front two road wheels and 1 on the last road wheel. The torsion bars were previously developed by Eletrometal for the M41B program. These torsion bars were made from 300M alloy steel, which was also used for the torsion bars of the M1 Abrams. The idler wheel was mounted on the front side of the vehicle, while the drive sprockets were installed in the rear.
The Tamoyo used Brazilian copies of the T19E3 tracks produced by Novatraçao. The suspension was protected by a side skirt. The T19E3 tracks had a width of 530 mm (20.8 inch), and a ground contact length of 3.9 meters (12.8 feet). This gave the Tamoyo a ground pressure of 0.72 kg/cm2 (10 lbs/in2) and a trench crossing ability of 2.4 meters (7.9 feet). The tank had a ground clearance of 0.5 meters (1.6 feet) and could climb a 0.71 meters (2.3 feet) tall vertical slope. It could climb a slope of 31 degrees, and be operated on a side slope of about 17 degrees. The vehicle had a fording capability of 1.3 meters (4.3 feet) and could neutral steer as well.
Turret
The Tamoyo 1’s turret was armored with welded homogeneous steel plates presented at various inclinations. Turret was meant to protect the Tamoyo from frontal 30 mm and all-round 14.7 mm fire. Like with the hull armor, these armor values were uncovered with the help of the writer’s contacts in the Brazilian Army.
Tamoyo 1 Turret Armor
Location
Thickness
Angle from vertical
Effective thickness
Gun Shield
50 mm (2 inch)
45
70 mm (2.75 inch)
Front
40 mm (1.6 inch)
Presented armor angle when firing at the front:
Front top : 60
Front side: 67
Front bottom: 45Angle of the front side when firing at the side:
20
Presented relative armor when firing at the front:
Front top : 80 mm (3.15 inch)
Front side: 100 mm (4 inch)
Front bottom: 57 mm (2.25 inch)Relative armor of the front side when firing at the side:
43 mm (1.7 inch)
Sides
25 mm (1 inch)
20
27 mm (1 inch)
Rear (not including storage box)
25 mm (1 inch)
0
25 mm (1 inch)
Top
20mm (0.8 inch)
90
20 mm (0.8 inch)
The Tamoyo turret was practically shaped like a less ergonomic M41 turret because of the use of flat plates instead of an intricately shaped side plate. It had a turret ring diameter of 2 meters (6.5 feet). The turret had 2 hatches, one for the commander and gunner, and one for the loader. The hatch for the commander was located on the middle right of the turret, while the loader’s hatch was located on the middle left. The gunner was located in front of the commander and had a passive day/night periscope located in a depression of the turret top. In addition, the gunner also has access to a direct sight telescope coaxial to the main gun. The commander had 7 periscopes available, which were passive day/night sights. A laser range finder was mounted on top of the main gun.
A set of 4 smoke dischargers was mounted on both sides of the turret front. It also had 2 handles on each side, behind the smoke dischargers, to enable the crew to climb on the turret. A pickaxe was mounted on the right side of the turret, behind the handles. Various mounting points for boxes and tools were available on the rear side plate of the turret as well, including a lifting eye on each side on both the rear and front side plates. Finally, a storage box was mounted on the rear of the turret and a jerrycan was then mounted on both sides of the storage box.
The turret top configuration seems to have undergone some minor changes during the development. 2 mounting points for antennas were located on each outer side on the rear top plate. In another turret design, the left mounting point was located just behind the loader’s hatch instead. In between the antenna mountings was the inlet for the ventilation system, as the Tamoyo had an NBC system available. In the middle were the two hatches and in front of the loader’s hatch was another component with an unknown purpose. In a single picture of the Tamoyo 2 with the 105 mm turret, this location is outfitted with a meteorological system.
The turret was armed with the BR 90 mm gun and a coaxial 12.7 mm heavy machine gun. In addition, the Commander’s station could be armed with a 7.62 mm machine gun for Anti-Air purposes. The turret had an electrical and manual turret drive and the gun had an elevation of 18 degrees and a depression of 6 degrees.
The turret of the museum piece had an 11 round stowage in the turret bustle on the left side and 10 rounds in ready racks, totalling in 21 rounds of 90 mm ammunition. The radio would have been located on teh right side of the Tamoyo, where the commander was situated. a ventilation system was located inbetween the radios and ammunition stowage.
Armament
The Tamoyo 1 was armed with an unstabilized Brazilian copy of the GIAT 90 mm CS Super 90 F4 gun. The Brazilian designation for this gun was ‘Can 90mm 76/90M32 BR3’. This gun was an L/52 gun that could handle a pressure of 2,100 Bar (210 MPa) and had a recoil stroke of 550 mm (21.6 inch). The gun had a recoil force of 44 kN for standard ammunition and 88 kN for APFSDS ammunition. The BR3 gun used APFSDS as its main anti-armor round due to the 52 caliber length and the incorporation of the single baffle muzzle brake, which allowed the firing of APFSDS projectiles. The BR3 would have had 5 types of ammunition available to it: canister, high explosive, high explosive anti-tank, smoke, and armor-piercing fin stabilized discarding sabot rounds.
Tamoyo Ammunition
Round
Capability
Effective Range
Velocity
Weight
APFSDS (armor piercing fin stabilized discarding sabot)
Heavy
NATO Single Plate: point blank (60 degrees 150mm)
NATO Triple Plate: 600 m (65 degrees 10 mm, 25 mm, 80 mm to simulate side skirt, road wheel and side hull respectively)Medium
NATO Single Plate: 1200 m (60 degrees 130 mm)
NATO Triple Plate: 1600 m (65 degrees 10 mm, 25 mm, 60 mm)
1,650 meters (1,804 yards)
1275 m/s
2.33 kg full projectile (5.1 lbs)
HEAT (high explosive anti tank)
130 mm (5.1 inch) at 60 degrees from vertical or 350 mm (13.8 inch) flat at any range.
1,100 meters (1,200 yards)
950 m/s
3.65 kg (8 lbs)
HE (high explosive)
Lethal radius of 15 meters (16 yards)
925 meters (1000 yards)
6900 meters (7545 yards) for long range HE
750 m/s (700 m/s for long range HE
5.28 kg (11.6 lbs)
Canister
Training projectile
200 meters (218 yards)
750 m/s
5.28 kg (11.6 lbs)
White Phosphorous – Smoke
Smoke round
925 meters (1000 yards)
750 m/s
5.4 kg (11.9 lbs)
The Tamoyo had stowage for 68 rounds of 90 mm ammunition according to sourcing, but the museum piece would have only had room for 51 rounds allthough stowage could have been missing. In addition, it was armed with a coaxial 12.7 mm machine gun and could be armed with a 7.62 mm machine gun on the commander’s station for anti-air purposes, with 500 and 3,000 rounds of ammunition respectively. The Tamoyo 1 also had 8 smoke discharges, of which four were installed on each side of the front turret. The turret had an electric and manual traverse system and the gun had an elevation and depression of 18 and -6 degrees, respectively.
The fire control system included a computer with unknown usage, most likely to better integrate the usage of day/night sights and the laser rangefinder which were used by the Tamoyo 1. This could potentially also mean a lead calculator and the integration of a meteorological system, although these were features of the Tamoyo 3, which used a much more advanced fire control system. The electric fire-control system, turret rotation and gun elevation were produced by Themag Engenharia and the Universidade de São Paulo (University of São Paulo). The Tamoyo 1 did not have a stabilized gun, while the Tamoyo 3 did incorporate this feature.
Other Systems
The electrics were powered by a main engine-driven main generator, which produced 24 volts. In addition, four 12-volt batteries were available when the main engine was stopped. The Tamoyo could be fitted with an NBC system and a heater as optional equipment. The NBC system could be mounted on the already existing ventilation system.
The vehicle used a radio which was also integrated with the M41C and the X1A2 tanks, capable of receiving the EB 11-204D and simpler frequencies. The radio also worked with AN/PRC-84 GY and AN/PRC-88 GY frequencies. The Tamoyo also had an intercom system for the entire crew which could be linked to the radio. The Tamoyo is said to have had a bilge pump as well, which might have been optional.
Variants
The MB-3 Tamoyo series had 7 variants in total. Four of these were combat variants, while the other 3 were engineering variants. Practically nothing is known about the engineering variants, as no sketches of these vehicles exist and the projects were cancelled with the shutdown of the Tamoyo program.
Tamoyo 2
The Tamoyo 2 was effectively nothing more than a Tamoyo 1 with an HMPT-500-3 transmission, which was requested to be developed by Bernardini, so that the company could provide a more modern vehicle. This transmission would allow the usage of an engine with more horsepower, as the HMPT could handle 600 hp, compared to 500 hp on the CD-500. Eventually, the Tamoyo 2 would serve as a brief testbed for the 105 mm armed turret of the Tamoyo 3, but would end up being scrapped with the end of the Tamoyo program.
Tamoyo 3
The Tamoyo 3 was the export version of the Tamoyo program, armed with a 105 mm L7, using a 736 hp engine, a CD-850 transmission, a much more advanced fire control system, and the incorporation of composite armor. The Tamoyo 3 was a serious attempt by Bernardini to try and sell the Tamoyo to the rest of the world. It was effectively a lighter Leopard 1, with potentially better frontal armor due to the planned composite and spaced armor package, and the usage of a low recoil 105 mm gun. The Tamoyo 3 would eventually be trialed and considered by the Brazilian Army as well in 1991, but failed due to economic issues and the increasingly cheaper stream of second-hand material after the end of the Cold War.
Tamoyo 4
The Tamoyo 4 was a plan to convert the TI-3 Tamoyo 1 to a Tamoyo 4 standard. The Tamoyo 4 was supposed to receive an MWM engine and a ZF transmission in order to fix the issues of the Tamoyo 1 which came to light during Army trials in 1988.
Since Bernardini had already considered the possibility of a ZF transmission for 900 to a 1,000 hp engine on the Tamoyo 3, it is quite likely that the Tamoyo 4 would also sport these characteristics. It is possible that the Tamoyo would have received the same MWM TDB 834 12 cylinder 1040 hp diesel engine as the EE-T1 Osório. This upgrade would have roughly doubled the hp to ton ratio from 16.6 to 33.3 (although this number would probably be limited, as it might cause issues with other components). Even the 736 hp Detroit 8V-92TA Diesel engine of the Tamoyo 3 would have raised the hp to ton ratio to a respectable 24.5. The EE-T1 Osório had about 24.2. The Detroit engine could supposedly be upgraded to higher hp as well.
In the end, Bernardini would not convert the Tamoyo 1 (TI-3) to a Tamoyo 4. The program was scrapped in 1991, while the Tamoyo (TI-3) was already taken apart before for a potential conversion but would never be reassembled.
Bulldozer, Bridge Layer, and Recovery Tamoyo
These three vehicles were planned, but never realised. The vehicles were designated as VBE Bulldozer (Viatura Blindada Especial Bulldozer, Special Armored Vehicle Bulldozer), VBE Lança Ponte (Viatura Blindada Especial Lança Ponte, Special Armored Vehicle Bulldozer Bridge Layer), and VBE Socorro (Viatura Blindada Especial Socorro, Special Armored Vehicle Recovery). These vehicles were part of the contract of 1984 with the army and were designated as P6, P7, and P8. They were supposed to all receive the DSI-14 engine and CD-500 transmission. It is very likely that the actual development of these projects would only really be initiated when the Brazilian Army started to acquire the Tamoyo 1.
An Anti-Air Tamoyo?
An AA design of the Tamoyo is suggested in the Jane’s Armour and Artillery 1985-86 book. No evidence of the existence of such a vehicle exists in Brazilian sources. The vehicle was supposed to be armed with a Bofors 40 mm L/70 but no further information was given. It might be possible that this version was confused with another Brazilian vehicle, the Charrua. Besides being an APC, the Charrua was proposed as a multiplatform vehicle, including a Bofors AA gun which was actually built. It is also likely that the AA Tamoyo might just have been mentioned as a possibility if any customer showed interest in such a vehicle, mainly for marketing reasons.
Engesa Enters the Fray
With the signing of the March 27th, 1984 contract, the development of the Tamoyo project was secured with Brazilian Army backing. In the same year, the vehicle seems to have been successfully trialed as well. But it seems that the Army’s stance regarding the Tamoyo project changed in 1986.
In 1982, Engesa broke the gentlemen’s agreement on which the Brazilian armored vehicle industry was founded. Engesa, which was supposed to focus exclusively on the development of wheeled armored vehicles, initiated the development of the EE-T1 Osório. Although the Osório was not directly developed for the Brazilian Army, Engesa still decided to use some of the initial requirements laid out by the Brazilian Army so that they could sell it to Brazil as well, but with a 105 mm gun instead. Engesa decided to increase the weight to make it more capable on the export market, but retain the 3.2 meters (10.5 feet) width.
The tank Engesa ended up with was a vehicle that outperformed the Tamoyo 1 in every aspect, except price. The Osório would outperform the later Tamoyo 3 as well in multiple aspects. In 1986, the Osório with 105 mm gun was trialed by the Brazilian Army. The Osório impressed the Brazilian Army so much that they practically seemed to have forgotten about their initial requirements of interchangeability. The Brazilian Government supposedly promised Engesa that they would buy 70 Osórios, but this would later increase to 150 or 300 Osórios according to sources. This decision effectively meant that the Army forgot about the Tamoyo project which they had initiated, which was tailor-made to Brazilian requirements, and decided to go with the Osório.
Fate
The now finished prototypes of the Tamoyo 1 were retrialed by the Brazilian Army in 1988. Considering various Tamoyos, like the Tamoyo 2 and 3, were already finished around 1986-1987, this date seems to be quite late. Flavio Bernardini noted in one of his memoirs that the Tamoyo program was ‘’Empurrada com a barriga” (English: Put under the belly)’ by the Army, which is a saying suggesting that the Army seems to have somewhat deliberately postponed the trials.
The second Tamoyo 1 (TI-2) was trialed by the Army in 1988, and subsequently rejected. The TI-2 was not fast enough and its acceleration was lacking as well. In addition, the oil filter was damaged and the gearbox was damaged due to cracking near the fixation points of the spur gears.
This rejection presented a few major issues. The first was that neither the Tamoyo 1 or the Tamoyo 2 could match the new requirements by the Army in their current configuration. Bernardini considered converting the Tamoyo 1 (TI-3) to a potential Tamoyo IV (4) version. The Tamoyo 4 would have used an MWM engine and ZF gearbox for its powerpack. This was viable since both MWM and ZF had sizable subsidiaries in Brazil at the time. The construction of a Tamoyo IV was never carried out.
By 1991, the construction of the Tamoyo 1 (TI-2), the Tamoyo 2 (TII), and the Tamoyo 1 (TI-3) had cost a little under 2.1 million US dollars (4.2 US Dollars in 2021). This suggests that a Tamoyo 1 would have cost about 700,000 US Dollars (1.4 million US Dollars in 2021) to manufacture a piece during the prototype stages. The cost per vehicle might have been less if the vehicle had reached serial production.
In 1991, the Tamoyo 3 was finally considered by the Army instead. The Tamoyo 3 would also face a brick wall, as the Army staff was split regarding the Tamoyo 3. One side was in favor of the Army sharing the costs of the evaluation of the Tamoyo 3, while the other side wanted to terminate the entire Tamoyo projects and that the costs of the evaluation should fall solely on Bernardini.
This was because the Tamoyo 3 was classified as a foreign vehicle instead of an indigenous design, since it used a lot of components that were not yet produced in Brazil. These components included the L7 cannon, automatic fire extinguishing sensors, and the fire control system among other components. The Army definitively canceled the entire Tamoyo project on July 24th, 1991 without testing the Tamoyo 3 even once. With this decision, Brazil effectively shut down any possibility of an indigenous designed and manufactured main battle tank for the Army.
Even worse, this decision may have sealed Bernardini’s fate as well, as the company closed its doors in 2001. If the Army had decided to acquire the Tamoyo tank, whether it would have been the Tamoyo 1, 2, 3, or 4, Bernardini would probably have lived on. The acquisition of the Tamoyo would mean much more than just buying the tanks. Maintenance support, supply of spare parts, further development and upgrade programs, and more nationally produced components would all give Bernardini a steady flow of income. More importantly, Bernardini’s survival and further development of the Tamoyo’s would have meant that the knowledge on designing tanks and all the advancements made in the field would have been retained in Brazil.
What Happened?
In a way, the Osório trials seem to have sent a signal to the Army that heavier main battle tanks, armed with guns over 90 mm, were the way forward. On top of that, it seems that the Army then decided to put their trust in the Osório program, barely considering the export version of the Tamoyo, which was built in 1987. Even worse, the Tamoyo 3 would be trialed as late as 1991, a year after the Osório project failed and a year after Engesa filed for bankruptcy. This only further solidifies the notion that the Army decided it wanted the Osório from Engesa and not the Tamoyo 1 or the Tamoyo 3 from Bernardini.
Brazil also underwent a political shift in 1985. The country transitioned from a military dictatorship towards a democracy again. With this shift, the newly reformed democracy found itself in a 10-year-long battle against hyperinflation and economic disaster. To give an idea of the inflation which the democracy inherited from the military dictatorship: inflation rose to 658.91% in between March 1984 and December 1985. The Brazilian economy would only start to recover from the rampant inflation around 1994. As a result of this crisis, the Brazilian government practically cut any acquisition of new material for the Brazilian Army.
Remaining Tamoyo 1s
Three out of four Tamoyo 1’s still exist to this day. 2 of these are completed prototypes and one is a completed shell. These prototypes are kept at various Army institutions like the CTEx and the CIBld. This is an interesting decision, as this means that none of the Tamoyo vehicles are available to the public in museums like Conde de Linhares and Militar Comando Militar Do Sul. By not presenting the Tamoyo to the public, the vehicle itself becomes much more obscure and paints a picture of the EE-T1 Osorio being the sole Main Battle Tank of Brazil.
X-30 Mock-Up
The X-30 mock-up still exists to this day and is presented at the CTEx as a monument. The CTEx is located in Guaratiba in the state of Rio de Janeiro. It seems to have had a few repaints during its time there, having received a gray paint scheme and a modern orange green scheme.
MB-3 Tamoyo 1 CIBld
One of the remaining Tamoyo 1’s is preserved at the CIBld, the Brazilian Armor Instruction Centre. This Tamoyo was most likely the first Tamoyo (TI-1) to have been built. This is because the second Tamoyo 1 is preserved at the CTEx and the third Tamoyo 1 was scrapped. When this Tamoyo arrived at the CIBld is unknown, but it has been on display at the CIBld Museum since at least 2010.
This Tamoyo does not have a fire extinguisher on both sides of the front hull, and it does not have a Laser range Finder. In addition, this Tamoyo can also be recognised by the single black-out marker next to the right headlight. This particular Tamoyo was used to obtain the armor thicknesses.
Recently, this particular Tamoyo 1 was restored in driving condition by the Army, which was made public on January 22nd 2022 with a video of it slowly driving into the workshop in Alegrete, Rio Grande do Sul State. According to contacts, the vehicle is basically a shell and is only repaired to drive around. Considering Brazil had to recently restore a number of M41C tanks of Uruguay which do have the DS-14 engine, it is definitely possible that the Tamoyo retained its original engine. The vehicle is thought to have been restored so it can drive during the 200 years of independence celebration parade on the 7th of September this year. It already made an appearance during the 100 years of tanks in the Brazilian Army celebration on November 8th 2021, but it was not yet in running condition as it was presented on the trailer of a truck.
MB-3 Tamoyo 1 CTEx
The second Tamoyo (TI-2) is said to be preserved at the CTEx, but no pictures of the Tamoyo 1 at the CTEx have been found. What is known, is that this Tamoyo was trialed during the 1988 trials, and subsequently displayed at the EsMB (Escola de Material Bélico, School of Military Materiel) in Rio de Janeiro. The vehicle was then stored at the IPD (Instituto de Pesquisas e Desenvolvimento, Research and Development Institute), the overarching institute of the CTEx, until 2003. At the IPD is received an inscription LTCM 1 (Laboratório de Tecnologia e Conceitos Móveis 1, Mobile Technology and Concepts Laboratory 1) with the 1 referring to the “first vehicle”. In 2003, the vehicle went to the CTEx in Rio de Janeiro.
This version is easily distinguishable by its Laser Range Finder and its two fire extinguishers. In addition, it has a black-out light next to each headlight as well.
The MB-3 Tamoyo 1 IPD
The final remaining Tamoyo 1 is the fourth Tamoyo 1 (TI-4) at the IPD. This Tamoyo is effectively nothing more than a shell. The overall steel construction of the hull and turret was completed, but did not progress any further. It is likely that this Tamoyo was cancelled in 1991, together with the cancellation of the Tamoyo project. The hull has ‘’Aqui nascem os blindados brasileiros’’ written upon it, translating to: ‘The Brazilian armored vehicles are born here’.
The vehicle was displayed as a monument in 2003 at the IPD location in Marambaia in Rio de Janeiro. IPD was absorbed by the CTEx in 2005. What happened with the Tamoyo afterwards is unknown. The Tamoyo is probably still there, but might also be lost.
Conclusion
The Tamoyo 1 was effectively a victim of its own conception. The Brazilian Army wanted a cheap vehicle that could share as many components with the M41C and the potential Charrua as possible. The Army had agreed to the specifications of the Tamoyo 1 in 1984, but only later seemed to have realized what their requirements for the Tamoyo 1 actually entailed for the program, and what they actually wanted in their future tank. The Osório was potentially the wake-up call for the Brazilian Army and the death of the Tamoyo projects.
The Tamoyo 1 could have been a vehicle that matched the Army requirements if the Army had requested for better components from the start and not delayed its trials until 1988 only to reject the obvious. The Tamoyo 1 concept in and of itself was not a bad one in the first place. It was cheap and it would have been able to take on the TAM. If the political and economical situation of Brazil had allowed it, the Tamoyo would have been an excellent vehicle in combination with the Charruas and the M41Cs.
In the end, the failure of the Tamoyo 1 program can be boiled down to 3 main issues. The lack of strategic vision of the Army regarding requirements, Engesa breaking the gentlemen’s agreement by building the Osório, and the economic and political situation of Brazil at the time.
The Tamoyo 1 itself was not an exceptional vehicle, and it is clear that the Tamoyo 3 would have been a much better and future-proof vehicle for the Brazilian Army. The tank can be summed up as a decent and realistic medium tank that was tailor-made for the Brazilian Army’s requirements at the time, but, like almost the entire Tamoyo project, ended up being overshadowed by the much more advanced and, for Brazil, unrealistic Osório Main Battle tank.
Specifications MB-3 Tamoyo 1
Dimensions (L-W-H)
6.5 meters (21.3 feet) and 8.77 meters (28.8 feet) with the gun pointing forward, 3.22 meters (10.6 feet), 2.2 meters (7.2 feet) to turret top and 2.5 meters (8.2 feet) in total.
Total weight
28 tonnes empty, tonnes combat-loaded (30.9 US tons, 33 US tons)
Crew
4 (commander, driver, gunner, loader)
Propulsion
Scania-Vabis DSI-14 turbocharged V8 500 hp diesel engine
Suspension
Torsion bar
Speed (road)
67 km/h (40 m/h)
Armament
90 mm BR3
Coaxial .50 caliber MG HB M2
Anti-Air 7.62 mm mg
Armor
Hull
Front (Upper Glacis) 40 mm at 65-70 degrees (1.6 inch)
Front (Lower Glacis) 40 mm at 45 degrees (1.6 inch)
Sides 19 mm at 0 degrees (0.75 inch)
Rear ?
Top 12.7 mm at 90 degrees
(0.5 inch)Turret
Front 40 mm at 60/67/45 degrees (1.6 inch)
Gun mantlet 50 mm at 45 degrees (2 inch)
Sides 25mm at 20 degrees (1 inch)
Rear 25 mm at 0 degrees (1 inch)
Top 20 mm at 90 degrees (0.8 inch)
Production
4+1 mock-up
Special thanks to Expedito Carlos Stephani Bastos, the leading expert in Brazilian vehicles, please visit his website for further reading on Brazilian vehicles: https://ecsbdefesa.com.br/, Jose Antonio Valls, an Ex-Engesa employee and expert in Engesa vehicles, Paulo Bastos, another leading expert of Brazilian Armored vehicles and the author of the book on Brazilian Stuarts and the website https://tecnodefesa.com.br, Adriano Santiago Garcia, a Captain in the Brazilian Army and ex-company commander on the Leopard 1 and ex-lecturer on the Brazilian Armored School, and Guilherme Travassus Silva, a Brazilian with whom I was able to endlessly discuss Brazilian Vehicles and who was always willing to listen to my near endless ability to talk about them.
Sources
Blindados no Brasil – Expedito Carlos Stephani Bastos
Bernardini MB-3 Tamoyo – Expedito Carlos Stephani Bastos
M-41 Walker Bulldog no Exército Brasileiro – Expedito Carlos Stephani Bastos
M-113 no Brasil – Expedito Carlos Stephani Bastos
Jane’s armour and artillery 1985-86
Brazilian Stuart – M3, M3A1, X1, X1A2 and their derivatives – Hélio Higuchi, Paulo Roberto Bastos Jr., and Reginaldo Bacchi
Moto-Peças brochure
Memoir of Flavio Bernardini
Author’s collection
Bernardini compra fábrica da Thyssen – O Globo, archived by Arquivo Ana Lagôa
The Centro de Instrução de Blindados
Tecnologia & Defesa magazines with courtesy of Bruno ”BHmaster”
With Expedito Carlos Stephani Bastos, Expert in Brazilian Armoured Vehicles
With Paulo Roberto Bastos Jr., Expert in Brazilian Armoured Vehicles
With Adriano Santiago Garcia, A Captain of the Brazilian Army and ex-company commander on the Leopard 1
Federative Republic of Brazil/Republic of Ecuador (1980s)
Light Tank – None Built
At some point in the 1980s, Ecuador sought to upgrade its fleet of M3A1 Stuarts by modernizing them with a new gun and engine. The country entered negotiations with the Brazilian company Bernardini, which in the mid-1970s had modernized the Brazilian M3 Stuart to X1 standard. The negotiations considered a refurbished M3A1 Stuart armed with a 60 mm HVMS gun, which also armed the Chilean M4 Sherman and M24 Chaffee, and a Detroit 6V53T engine. Although the project would never leave the concept stage, the X1 60 HVMS would have had the best anti-tank capabilities of the entire X1 family. Sadly, a limited budget and an order of 32 EE-9 Cascavels by the Ecuadorian Army seem to have put an end to the project.
The M3A1 Stuart in Ecuador
Ecuador received the M3A1 Stuart under Lend-Lease from the United States. With World War 2 in full swing and the United States at war with the Axis, the United States sought to secure its position on the American continent. Through multiple ways, the United States would successfully influence all the American countries to either side with the Allies or stay neutral throughout the conflict. Ecuador remained neutral for the majority of World War 2, only declaring war on Germany and Japan on February 2nd, 1945.
In their attempt to secure the American continent, the United States realized that most of the equipment of the armies and infrastructure of the American countries were seriously outdated. Thus, Ecuador would receive military materiel from the United States to modernize the country’s Armed Forces for the safety of the American continent, but also as a deterrent for any country on the continent itself to join the war on the Axis side.
Ecuador received M3A1 Stuarts, M3 Scout Cars, and machine guns through Lend-Lease. In exchange, the United States could use the Galapagos Islands (off the coast of Ecuador, in the Pacific) as a base during World War 2. Ecuador received 42 M3A1 Stuarts, which arrived in 1943, after the Ecuadorian-Peruvian War of 1941. Supposedly, the M3 Stuarts were delivered to Ecuador in a non-combat ready state. If this meant that the Americans had not delivered the ammunition with the tanks or if the Americans had done something else to make them non-combat ready is unknown. The reason for the United States to supposedly deliver them in this state was to prevent a revenge attack by the Ecuadorians on Peru after their defeat during the Ecuador-Peruvian War. It is unclear how far these statements on combat readiness are true, so it is wise to take them with a grain of salt.
The X1
The first X1 vehicle was developed and presented at the Brazilian Independence Day Parade on September 7th 1973. The X1 was a modernization project of the M3 Stuart, carried out by the Parque Regional de Motomecanização da 2a Região Militar (PqRMM/2) (English: Regional Motomecanization Park of the 2nd Military Region), alongside Bernardini and Biselli, two Brazilian companies. The PqRMM/2 was responsible for the development of the wheeled vehicles, but also for the tracked vehicles of the Brazilian Army at the time, and were under the supervision of the Diretoria de Pesquisa e Ensino Técnico (DPET) (English: Army Research and Technical Educational Board), which coordinated the projects.
The tracked vehicles were researched and developed by a team of engineers within the Army and PqRMM/2, which were part of the Centro de Pesquisa e Desenvolvimento de Blindados (CPDB) (English: Centre for the Research and Development of Tanks). The CPDB was a research group of Army engineers which analyzed the possibilities of locally produced tanks. The first goal was to develop a new family of light tanks using the M3 Stuart as its basis.
The reasons for the M3 Stuart modernization were the lack of new and cheap materiel from the United States (then involved in the Vietnam War), the fact that they were the most numerous vehicles to be converted, that they were cheap to run and maintain, and their lightweight made them perfect for fighting on the difficult terrains of Brazil and their neighboring countries if needed. But the most important reason was that they were relatively easy and low risk to convert in order to gain experience to eventually build a national Brazilian tank. The M41s which Brazil had at the time were their best vehicles and much more risky to improve with the lack of experience.
After having successfully developed the first X1, a pre-series of 17 vehicles was ordered. These vehicles would, due to extensive delays, finally be delivered in 1976. The X1 was armed with a 90 mm D-921 low-pressure gun and had a Scania-Vabis DS-11 A05 CC1 6-cylinder in-line 256 hp diesel engine.
Bernardini and Biselli
For the construction of the X1, multiple parties and companies were involved. The two most important companies which built the X1 were Bernardini and Biselli. Both companies manufactured truck bodies and Cash-in-Transit vehicles at the time and came in contact with the Brazilian Armed Forces by manufacturing trucks for the Brazilian Marine Corps and the Army. Since both companies had some experience in the manufacture of armored vehicles, and with Bernardini being a manufacturer of safes and armored doors, they were requested by the Brazilian Army to help build the X1. Biselli quit the X1 project altogether around 1976, leaving the X1 family fully in the hands of Bernardini. In 1982, Bernardini was contracted by the Brazilian Army to develop a family of vehicles on the M3 Stuart and X1 platform. This contract would result in a family of vehicles, for example, a recovery version and a mortar carrier.
It is important to note that since Biselli quit the X1 project entirely around 1976, they had nothing to do with the X1 60 HVMS project for Ecuador. In fact, every development of the X1 family undertaken after 1976 was done by Bernardini, and the intellectual property of the vehicle was completely signed off to Bernardini by the Army.
Company/Army
Component(s)
United States
The M3 and M3A1 Stuart
Biselli
Hull extension, engine installation, equipment installation, and track mounting
Bernardini
Turret and suspension
CSN
Steel armor
Novatração
Tracks
DF Vasconcelos
Periscopes
Scania-Vabis
Engine
PqRMM/2
Stripping of the Stuart, revision of differential and transmission, radio installation, and testing
PqRMM/3
Overhaul and selection of M3 Stuarts
An X1 for Ecuador?
Very little is known about the X1 60 HVMS for Ecuador. According to sources, the negotiations for the conversion of an unknown amount of Ecuadorian M3A1 Stuarts were carried out at some point in the 1980s. In total, Ecuador had received 42 M3A1 Stuarts, but it is unlikely that all 42 vehicles were still in service, or even fit for refurbishment at all. It is estimated that Ecuador might have been interested in the conversion of around 30 M3A1 Stuarts. This estimation is based on an order of 32 EE-9 Cascavels which might have been ordered instead of the X1 60 HVMS.
The Ecuadorian Army asked for the refurbishment of their existing M3A1 Stuart, rearming them with the 60 mm HVMS, and remotorizing them with a Detroit 6V53T diesel engine. It is thought that the vehicle would effectively be an X1 with changes to the turret to mount the 60 mm cannon and a new engine.
It is estimated that the negotiations between Ecuador and Bernardini started at some point between 1980 and 1984, and most likely from 1982 to 1983. The reason for this is that negotiations were done in the 1980s, and Bernardini received the intellectual property and the contract to develop a family of X1 vehicles in 1982. Considering the X1 60 HVMS never got much further than the concept stage, it is very likely that the negotiations were short and might even only have happened for about a year. The reason given for the cancellation of the project was due to changes at the top of the Ecuadorian Army.
A few factors can be taken into account which might have led to the cancellation of the X1 60 HVMS project and why it is thought that the project was canceled in 1983. From 1977 to 1984, Ecuador was cutting the Army’s budget every year, reaching its lowest point in 1984. The budget of the Ecuadorian Army was somewhat limited for the acquisition of armored vehicles. In addition, 32 EE-9 Cascavels, armed with 90 mm low-pressure guns, were bought from Engesa in 1983 and delivered in 1984. It is very likely that the EE-9 Cascavel order sucked up the budget of the Ecuadorian Army, and combined with another budget cut in 1984, the Army simply did not have the money to spend on the conversion of their M3A1 Stuart tank fleet.
In addition, another case can be made for the EE-9 against the X1. The EE-9 was a brand new vehicle, while the X1 would be converted from 40-year-old vehicles. As shown by the X1 conversion in Brazil, certain issues cannot simply be fixed due to the sheer age of the refurbished vehicle. It begs the question, why spend money upgrading something old which will still retain unsolvable issues, when one could buy brand new armored cars?
The 60 HVMS gun
The 60 mm Hyper Velocity Medium Support L.70 gun was developed in 1977 by the Israeli Military Industry and the Italian company OTO-Melara to provide the infantry with a towed or Infantry Fighting Vehicle-mounted gun that could provide excellent anti-tank fire and adequate anti-infantry support. It was tested by Israel on a modified M113 with a turret and by the Italians on the VBM Freccia prototype and on a modified VCC-80 Dardo, but was not accepted into service.
In fact, the 60 HVMS IMI-OTO (known in Italy as the HVMS 60/70 OTO-Melara) had excellent anti-tank performance and was able to penetrate, with its M300 APDSFS-T (Armor-Piercing Fin-Stabilized Discarding Sabot – Tracer), 120 mm of Rolled Homogeneous Armor (RHA) angled at 60° at a 2,000 m range. This was the equivalent of the frontal armor of a Soviet T-62.
In one test, it allegedly managed to penetrate the side armor of two T-62s from side to side at 2,000 m. As an example, a 105 mm APDSFS-T projectile from the Royal Ordnance L7 penetrated the same armor at the same distance. However, the 60 mm gun weighed 700 kg with a total projectile weight of only 6 kg and a length of 62 cm, while the Royal Ordnance L7 weighed 1,200 kg with projectiles weighing around 18 kg and a length of about 95 cm.
The tungsten penetrator of the APDSFS-T projectile weighed 0.87 kg with a diameter of 17 mm and a total length of 292 mm. It had a muzzle velocity of 1,620 m/s thanks to the high-pressure barrel, giving it very good accuracy up to a 2,500 m range. The HE-T (High-Explosive – Tracer) projectile weighed 7.2 kg.
The Theoretical X1 60 HVMS Design in Detail
The specifications and design of the X1 60 HVMS are mainly based on the existing specifications of the X1, with adjustments for the 60 HVMS gun and the Detroit 6V53T engine, to give an idea of what a 60 HVMS armed X1 might have been.
The length measurements of the X1 turned out to be incorrect in the sources. As a result, all the length values were calculated and are reasonable estimates. The X1 60 HVMS would have weighed about 17 tonnes (18.7 US tons) and would be 7.24 meters (23.7 feet) long including the gun, compared with the 6.04 meters (19.8 feet) of the normal X1, with a 5.04 meters (16.4 feet) long hull, 2.4 meters (7.9 feet) width, and 2.45 meters (8 feet) high. Although the 60 HVMS was about 300 kg heavier than the original 90 mm D-921, the difference in weight would be compensated by the Detroit engine, which was about 300 kg lighter than the original Scania engine.
It would have had a crew of four, with the driver located on the front left of the hull, the co-driver on the front right of the hull, the commander/loader on the left side of the turret, and the gunner on the right side of the turret.
Hull
The hull of the X1 HVMS was to be a lengthened and modified M3A1 Stuart hull. As such, the overall protection for most of the X1 HVMS’ hull remained the same as that of the M3A1. The upper front plate of the X1 HVMS had an armor thickness of 38 mm (1.5 inch) at 17 degrees vertical, a middle front plate of 16 mm (0.6 inch) at 69 degrees, and a lower front plate of 44 mm (1.7 inch) at 23 degrees. The frontal cheek plates transitioning to the side plates were 28 mm (1.1 inch) thick. Its sides were 25 mm (1 inch) thick and angled at 10 degrees from vertical, while at the engine bay the sides consisted of two plates of 25 mm spaced from each other. This is because in the crew compartment, a hole was grinded out of the original plates for use as stowage, while this did not happen at the rear. The rear armor was the same as the M3 Stuart, being 25 mm (1 inch). The top plate was 15 mm (0.6 inch) thick and the floor plate gradually decreased in thickness from 13 mm at the front to 10 mm (0.5 to 0.4 inch) in the rear.
The rest of the X1 HVMS would have a very similar layout as the Stuart, like the original X1. The X1 had two headlights, one on each side of the front mudguards, two towing hooks on the front hull, and a .30 caliber hull machine gun on the right side. The driver had a two-piece hatch, while the co-driver had a single-piece hatch in the production versions of the X1. Depending on its variant, the X1 would either have a curved or angled rear plate, with the curved rear plate coming from the M3A1 Stuart.
Mobility
The X1 HVMS was to be powered by a Detroit 6V53T V6 turbocharged 260 hp diesel engine. This engine produced 260 hp at 2,200 rpm, giving the vehicle a horsepower per tonne ratio of 15.3. It would have used the same, but revised and using some locally produced components, 5 speed and 1 reverse transmission and differential as the original Stuarts. The X1 had a top speed of 55 km/h (34 mph) on roads and an operational range of 520 kilometers (323 miles).
The X1 HVMS would have used a copied and slightly altered VVS suspension system from the 18-ton M4 artillery tractor. It had 4 road wheels divided over two bogies, with 2 bogies per track, two return rollers on each side, a drive sprocket in the front, and an idler wheel on the rear. The 18-ton M4 suspension gave the X1 HVMS a ground pressure of 0.59 kg/cm2 (8.4 psi). The X1 had an on-ground track length of about 3.22 meters (10.6 feet) and could cross a trench of 1.2 meters (3.9 feet).
Turret
It is thought that the X1 HVMS would most likely have kept the BT-90A1 turret of the X1, although adjusted for the 60 mm HVMS gun. Considering the HVMS has a recoil weight of 500 kg compared to 200 kg for the D-921, the trunion of the turret would have most likely needed reinforcement. The recoil length of the HMVS, however, was shorter at 270 mm compared to 550 for the 90 mm.
The production versions of the X1 used the BT-90A1 turret, which used periscopes from Vasconcelos S/A. This company had previously provided periscopes for the VBB-1 4 x 4 wheeled vehicle. The turret was armored with 28 mm (1.1 inch) thick steel plates at various angles all-round to protect it from .50 caliber machine gun fire at 200 meters (218 yards). The gun shield and turret top were armored with 15 mm (0.6 inch) plates. The overall turret layout and the internal turret construction and components were more or less copied from the French H-90 turret. It had the exact same turret ring and its overall shape seems to match the H-90. In addition, in the first BT-90 turret, a lot of equipment was carried over from the H-90, such as the periscopes.
The BT-90A1 turret had a mount for a .50 machine gun on the left side, in front of the commander’s cupola. The commander’s cupola’s structure was slightly raised from the turret top to provide the commander with a 360º view. The antenna of the radio sets was located behind the gunner’s cupola on the right side of the turret, allong with the radio sets which were located on the right side of the turret bustle. The left side of the turret bustle had space to store 10 90 mm rounds. In addition, the X1 could mount two smoke dischargers on both sides of the turret rear, although these seem to not have always been mounted on the vehicles.
Armament
The X1 60 HMVS was to be armed with the 60 mm HVMS gun. The HVMS gun would provide a couple of advantages over the 90 mm D-921 of the X1. Most notable was the heavily increased initial muzzle velocity of the APDSFS round for the HVMS gun of 1,620 m/s compared to 865 m/s for the HEAT round of the 90 mm gun of the X1. The APFSDS round would also retain its velocity much better due to better aerodynamic properties compared to the 90 mm round. The increased muzzle velocity combined with the small sub-caliber round would make the HVMS gun much more effective in the anti-tank role than the D-921 gun.
Since the D-921 gun fired its round with a much slower muzzle velocity, it became much less accurate as well. Not only did the gun need to fire the HEAT round at an angle to compensate for the lack of velocity, the gunner would also have to take the slower travel time into account while leading for a target. Overall, the longer the travel time of the round, the less accurate it gets.
Performance-wise, the HEAT round of the D-921 and the APFSDS round of the 60 mm HVMS were about equal in terms of penetration at 2,000 meters, at around 120 mm at 60º. However, the D-921 only had an effective range of 1,500 meters, meaning that the 60 mm HVMS would not only be more accurate, but also more effective at close ranges. All in all, the 60 mm HVMS was a much better anti-tank gun than the D-921, but compromised with a much lighter HE shell of 2.9 kg compared to 5.28 kg for the D-921.
120 mm at 60 degrees from vertical at 2000 meters.
2,500 meters
1,620 m/s
HE (High Explosive)
–
–
–
It is unknown how many 60 mm rounds the X1 HVMS could have stored. The standard X1 stowed 18 rounds in the turret and another 10 in the hull. The X1 HVMS could probably have stored a little more. In addition to the 90 mm, the X1 mounted a turret top .50 caliber machine gun for the commander, a coaxial .30 machine gun, and a .30 machine gun for the co-driver in the hull.
Conclusion
Although the X1 60 HVMS was a very interesting project and would have greatly improved the anti-tank capability of the M3A1 Stuarts and the X1 family, it seems that the project lost to the EE-9 Cascavel. The basis of the X1 60 HVMS was 40 years old, which would make some issues unfixable due to the longevity of the platform. Combined with the decreasing budget of the Ecuadorian Army, the X1 60 HVMS was simply not meant to be. There was no money, the basis was too old, and the EE-9 was bought instead, dooming the project to obscurity.
Illustrations
Specifications CCL X1
Dimensions (L-W-H)
7.24 meters (23.7 feet) long including the gun x 2.4 meters (7.9 feet) x 2.45 meters (8 feet) tall
Total weight
17 tonnes (18.7 US tons)
Crew
4 (Driver, Co-driver, Commander-Loader, Gunner)
Propulsion
Detroit 6V53T V6 turbocharged 260 hp diesel engine
Front (Upper Glacis) 38 mm (1.5 inch) at 17 degrees
Front (Middle Glacis) 16 mm (0.6 inch) at 69 degrees
Front (Lower Glacis) 44 mm (1.7 inch) at 23 degrees
Sides 25 mm (1 inch)
Rear 25 mm (1 inch)
Top 15 mm (0.6 inch)
Floor 13 to 10 mm (0.5 to 0.4 inch)
Turret
28 mm (1.1 inch) allround
15 mm (0.6 inch) top and gun shield
Production
None (concept only)
Special thanks to Expedito Carlos Stephani Bastos, the leading expert in Brazilian vehicles, please visit his website for further reading on Brazilian vehicles: https://ecsbdefesa.com.br/, Jose Antonio Valls, an Ex-Engesa employee and expert in Engesa vehicles, Paulo Bastos, another leading expert of Brazilian Armored vehicles and the author of the book on Brazilian Stuarts and the website https://tecnodefesa.com.br, Adriano Santiago Garcia, a Captain in the Brazilian Army and ex-company commander on the Leopard 1 and ex-lecturer on the Brazilian Armored School, and Guilherme Travassus Silva, a Brazilian with whom I was able to endlessly discuss Brazilian Vehicles and who was always willing to listen to my near endless ability to talk about them.
Federative Republic of Brazil (1976)
Light Tank – 1 Prototype Built
At the beginning of the 1970s, the Brazilian Army started developing armored vehicles, starting with wheeled vehicles. After having successfully developed the prototype concepts which would become the EE-9 Cascavel and the EE-11 Urutu, the Brazilians looked to tracked vehicles. Like the previous wheeled vehicle projects, the engineers started small. They began by remotorizing readily available M3 Stuarts, and then started developing the vehicle that is known as the X1 light tank. The X1 was a modernization of the Stuart, which was armed with a low-pressure 90 mm gun, and would be developed into an entire family of vehicles.
One of these vehicles was a planned improvement of the X1 tank. The X1 had some limitations because of the components it used and some basic concepts. To fix these issues, the Brazilian Army engineers started the development of the X1A1, which was effectively a lengthened X1 with improved components.
The X1 Project
In 1973, the first X1 vehicle was developed and presented at the Brazilian Independence Day Parade on September 7 of the same year. The X1 was a modernization project of the M3 Stuart, carried out by the Parque Regional de Motomecanização da 2a Região Militar (PqRMM/2) (English: Regional Motomecanization Park of the 2nd Military Region), together with Bernardini and Biselli, two Brazilian companies. The PqRMM/2 was responsible for the development of the wheeled vehicles, but also for the tracked vehicles of the Brazilian Army at the time, and were under the supervision of the Diretoria de Pesquisa e Ensino Técnico (DPET) (English: Army Research and Technical Educational Board), which coordinated the projects.
The tracked vehicles were researched and developed by a team of engineers within the Army and PqRMM/2, which were part of the Centro de Pesquisa e Desenvolvimento de Blindados (CPDB) (English: Centre for the Research and Development of Tanks). The CPDB was a study group of Army engineers which analyzed the possibilities of locally produced tanks. The first goal was to develop a new family of light tanks using the M3 Stuart as its basis.
The reasons for the M3 Stuart modernization were the lack of new and cheap materiel from the United States (then involved in the Vietnam War), the fact that they were the most numerous vehicles to be converted, they were cheap to run and maintain, and their lightweight made them perfect for fighting on the difficult terrains of Brazil and their neighboring countries if needed. But the most important reason was that they were relatively easy and low risk to convert in order to gain experience to eventually build a national Brazilian tank. The M41s which Brazil had at the time were their best vehicles and much more risky to improve with the lack of experience.
After having successfully developed the first X1, a pre-series of 17 vehicles was ordered. These vehicles would, due to extensive delays, finally be delivered in 1976. At this point, various flaws of the X1 were already found and the X1A1 already developed.
Bernardini and Biselli
For the construction of the X1A1, multiple parties and companies were involved. The most important two companies which built the X1A1 were Bernardini and Biselli. Both companies manufactured truck bodies and value transport vehicles at the time, and came in contact with the Brazilian Armed Forces by manufacturing trucks for the Brazilian Marine Corps and the Army. Since both companies had some experience in the manufacture of armored vehicles, and with Bernardini being a manufacturer of safes and armored doors, they were requested by the Brazilian Army to help build the X1. After the X1 was successfully developed, Bernardini and Biselli started developing the X1A1 together with the PqRMM/2 and the CPDB engineers. Although Biselli would never fully commit to the project, Bernardini would commit and eventually become the tank counterpart to Engesa’s wheeled vehicles.
Company/Army
Component(s)
United States
The M3A1 Stuart
Biselli
Most likely: Hull extension, engine installation, equipment installation, and track mounting
Bernardini
Most likely: Turret and suspension
CSN
Steel armor
Novatração
Tracks
DF Vasconcelos
Periscopes
Scania-Vabis
Engine
Development
The exact starting point for the development of the X1A1 is unknown. Considering the first X1 was still extensively tested in 1974, and the X1A1 was first presented at the Independence Day Parade of 1976, it can be estimated that the vehicle might have been developed anywhere between 1975 and September 1976. Considering that the first X1 was developed and built in a span of just 2 months, it is not unlikely that the X1A1 started its development in early 1976.
The development of the X1A1 was meant to fix some issues identified on the X1. The most notable were the replacement of the massive idler wheel from the 18-ton M4 Artillery Tractor suspension, which had replaced the original M3 Stuart suspension on the X1, and the replacement of the M3 Stuart transmission with the transmission from the 18-ton M4.
The large ground touching idler wheel of the 18-ton M4, was a perfect solution to provide more track length while not needing a particularly large hull. The downside of these types of idlers is that they are made for relatively slow-moving vehicles, which the X1, at 55 km/h, was not. The high speed and weight of the X1 caused premature wear on the swing arms of the idler, which would eventually start to crack.
To fix this issue, it was decided to replace the ground-touching idler of the 18-ton M4 with the idler of the M4 Sherman. This meant that the idler would not provide the on-ground track length which was needed for the vehicle. As a result, an additional bogie was added, totaling three sets of bogies per side. In essence, a sort of 18-ton M4 Tractor/M4 Sherman hybrid suspension was created.
Because of the way a bogie has to be installed, the hull of the X1A1 had to be significantly lengthened compared to the M3 Stuart. The hull was lengthened by about 0.8 meters to accommodate the newly designed suspension and thus the required on-ground track length. The on-ground track length of the X1 was about 3.22 meters (10.6 foot), while the X1A1 was about 3.66 meters (12 foot) in comparison.
The lengthened hull brought a few extra advantages. A larger fuel tank was installed and more ammunition could be stored in the hull compared to the X1, increasing from 10 to 34 90 mm rounds.
The lengthened hull also enabled the engineers to design a larger turret bustle for the original BT-90A1 turret. The entire turret was constructed out of 28 mm (1.1 inch) thick steel plates, while the turret top and gun shield were armored by 15 mm (0.6 inch) plate steel. The extension of the turret bustle meant that an extra radio could be installed in addition to 24 90 mm rounds, compared to 10 rounds in the X1 turret.
All these changes caused the vehicle to increase in weight, which meant that larger brakes had to be installed to compensate for this increase. The X1A1 was finished somewhere before the Independence Day Parade of September 7th 1976. The vehicle would gain its nickname during a promotional film, when General Pedro Cordeiro de Mello, head of the PqRMM/2 and also the one who named the X1, named it Carcará, after an indigenous crested bird. It would be officially designated as Viatura Blindada de Combate – Carro de Combate MB-1A (VBC-CC MB-1A), (English: Armored Fighting Vehicle – Combat Car MB-1A, with MB meaning Medio Bernardini or Medium Bernardini). Considering the X1’s similar designations, it would most likely have also been referred to as Carro de Combate Leve X1A1 Carcará (CCL X1A1 Carcará), (English: Light Combat Car X1 Carcará), but this is more of an educated guess that cannot be actually confirmed. The X1A1 used EB11-376 as its vehicle number in the Brazilian Army, most likely being converted from an M3A1 Stuart which bore the same number and was owned by the CPDB.
Somewhere around this time, Biselli left the X1 family projects. Although the exact reasons are unclear, there are some statements that Biselli had some internal struggles, and Bernardini demanded more recognition for their efforts in the X1 project. In addition, it is also suggested that Biselli saw limitations in the defense industry and decided that focussing on the civilian industry was more profitable, while taking on more of a support role in the defense industry. With Biselli quitting the project, all tank development would be taken on by Bernardini, which would one day build the MB-3 Tamoyo main battle tanks.
The X1A1 in Detail
Multiple characteristics are presented incorrectly in the sources. As a result, all the length values were calculated with ratios and are reasonable estimates. Most of the other values are rough estimates. The X1A1 weighed somewhere between 17 and 19 tonnes (18.7 to 21 US tons) and was 7.04 meters (23.1 feet) long including the gun, had a hull of about 6.04 meters (19.8 feet), 2.4 meters (7.9 feet) wide, and 2.45 meters (8 feet) tall. It had a crew of four, with the driver located on the front left of the hull, the co-driver on the front right of the hull, the commander/loader on the left side of the turret, and the gunner on the right side of the turret.
Hull and Armor
The hull of the X1A1 was a lengthened and modified M3A1 Stuart hull, recognizable by the curved rear plate. As such, the overall protection for most of the X1A1’s hull remained the same as the M3. The thickness of the plates which were used to lengthen the hull is unknown but are estimated to be similar to those of the M3 Stuart and X1. The upper front plate of the X1A1 had an armor thickness of 38 mm (1.5 inch) at 17º vertical, a middle front plate of 16 mm (0.6 inch) at 69º, and a lower front plate of 44 mm (1.7 inch) at 23º. The frontal cheek plates transitioning to the side plates were 28 mm (1.1 inch) thick. Its sides were 25 mm (1 inch) thick and angled at 10 degrees from vertical, while at the engine bay the sides consisted of two plates of 25 mm spaced from each other. This is because in the crew compartment, a hole was grinded out of the original plates for use as stowage, while this did not happen at the rear. The rear armor was the same as the M3 Stuart, being 25 mm (1 inch). The top plate was 15 mm (0.6 inch) thick and the floor plate gradually decreased in thickness from 13 mm at the front to 10 mm (0.5 to 0.4 inch) in the rear.
The rest of the X1A1 had a very similar layout as the Stuart. It had two headlights, one on each side of the front mudguards, two towing hooks on the front hull, and a .30 caliber hull machine gun on the right side. The driver had a two-piece hatch, while the co-driver had a single-piece hatch.
Mobility
The X1A1 was powered by a Scania-Vabis DS-11 A05 CC1 6-cylinder in-line 256 hp diesel engine. A difference with the X1 is that the X1A1 uses more drive components from the 18-ton M4 instead of those of the M3 Stuart. This meant that the X1A1 had the same 3-speed transmission as the 18-ton M4. Another interesting detail is that the steering levers of the vehicle were mounted on the top of the hull instead of the bottom. The X1A1 had a top speed of potentially 50 to 55 km/h (31 to 34 mph) on roads and an operational range of 520 km (323 miles).
The X1A1 used a copied and altered VVS suspension system of the 18-ton M4 artillery tractor. It had 6 road wheels divided over three bogies, with 3 bogies per track, 3 return rollers on each side, a drive sprocket in the front and an M4 Sherman idler wheel on the rear. The newly designed 18-ton M4 Tractor/M4 Sherman hybrid suspension gave the X1A1 a ground pressure of 0.55 kg/cm2 (7.8 psi). The X1A1 had an on ground track length of about 3.66 meters (12 foot) and could cross a trench of 6.1 meters (4.9 foot).
Turret
The X1A1 turrets were practically the exact same turrets as the X1’s BT-90A1 turrets, except for the extended turret bustle. The front was armored with 28 mm (1.1 inch) thick steel plates all round at various angles to protect it from .50 caliber machine gun fire at 200 m (218 yards). the turret top and the gunshield were armored with 15 mm (0.6 inch) plates. It is suggested that the overall turret layout and the internal turret construction and components were more or less copied from the French H-90 turret. It had the exact same turret ring and its overall shape seems to match the H-90. In addition, in the first BT-90 turret of the X1, a lot of equipment was carried over from the H-90, like the periscopes.
The X1A1 turret had a mount for a .50 cal machine gun on the left side of the turret, in front of the commander’s cupola. The commander’s cupola’s structure was slightly raised from the turret top to provide the commander with a 360º view. The antenna of the radio sets was located behind the gunner’s cupola on the right side of the turret. Placement-wise, there were a few differences with the original X1 turret. Spare tracks were mounted on the turret bustle sides which would act as additional armor. This placement of the spare tracks meant that the smoke dischargers were moved to the front of the turret, in a set of 3 dischargers on each side. A small light was also installed on the turret side of the commander’s cupola.
Armament
The X1A1 was armed with the 90 mm D-921 low-pressure gun. The low-pressure gun allowed vehicles like the X1, but also the 5 tonne AML-90, to mount a gun on light platforms with significant armor penetration capabilities.
The trade-off with these types of guns is that Kinetic AP or APFSDS rounds are not really worth it from a penetration point of view compared to the HEAT rounds these guns fired. A 90 mm APFSDS round for the later Cockerill guns would penetrate 100 mm (3.9 inch) of armor at 60º from vertical at a range of 1,000 m (1,090 yards), compared to 130 mm (5.1 inch) at 60º for HEAT at any range. The D-921 did not even have AP rounds available for this reason.
The X1A1 had access to HEAT, High Explosive Squash Head (HESH), and High Explosive rounds. The HEAT round was meant for anti-armor purposes and was the X1A1’s anti-tank round. The HESH round was mainly meant for bunkers, walls, and light vehicles, and not as ‘anti-armor’ ammunition. The HE round was used as a general-purpose support round. Another downside of these low-pressure guns was their limited combat range and decreased velocity. This meant that the gun became much less accurate at longer ranges compared to high-velocity guns, which could also outrange the low-pressure 90 mm guns.
Round
Capability
Effective range
Velocity
HEAT (High Explosive Anti Tank)
320 mm flat at any range.
1,500 meters (1,640 yards)
750 m/s
HE (High Explosive)
Lethal radius of 15 meters (16 yards)
–
650 m/s
The X1A1 stowed 24 rounds in the turret, and an additional 34 rounds in the hull, for a total of 58 rounds of 90 mm ammunition. In addition to the 90 mm, the X1A1 mounted a turret top .50 caliber machine gun for the commander, a .30 coaxial machine gun, and a .30 machine gun for the co-driver in the hull.
Fate
In the end, after all the improvements done on the X1A1 in an attempt to fix the mistakes of the X1, the Brazilian engineers accidentally ‘broke’ the vehicle even more. Although most of the issues with the individual components were solved, some issues were unfixable, as they resulted from the simple fact that the basis of the X1A1 was a 30-year-old M3A1 Stuart. The torque converter also provided problems throughout the X1 family, as the quality of diesel used by the Brazilians was quite poor. This resulted in premature wear of the components.
The biggest issue though, and what really caused the engineers to break the vehicle more than they fixed the X1, was that the length to width ratio was off. The X1A1 was too long and too narrow. This made the X1A1 a very sluggish and hard to steer vehicle, which worsened the longer the vehicle was operated. An anecdote describes the steering issues of the X1A1. The X1A1 was the only vehicle of the X1 family to have its steering levers attached to the roof of the hull instead of the floor. In an instance, a driver had to apply so much force in order to turn, that he pulled out the lever from its fixation point. This problem was only worsened because the X1A1 also suffered from an increasingly problematic differential, on top of the length to width ratio of the vehicle.
The engineers analyzed how they could potentially fix these issues, but they quickly discovered it was not worth the resources. They would have had to widen each M3 Stuart to achieve the needed length to width ratio, and also adjust most of the components to fit in this new configuration. In addition, the fixed X1A1s would still suffer from the same issues as the other X1s, because the same old Stuart was still the base vehicle. As a result, it was decided that it was easier to start developing Brazil’s first and practically only serially produced tank in Brazilian service, which was completely designed in Brazil. This new vehicle became the X1A2 and would see limited service in the Brazilian Army, as the project was fairly quickly canceled for the much more promising M41 modernization projects.
The only produced prototype now serves as a gate guardian at the PqRMnt/1 in Rio de Janeiro.
Conclusion
For all intents and purposes, the X1A1 itself was a failure. The Brazilian engineers literally found the limits to what one could do with an M3 Stuart. Even though the X1 program was a sort of trial and error program to gain experience, the X1A1 was a step too far in the modernization of obsolete vehicles. The significant mobility issues and the continued usage and wear of old M3 Stuart components would cause the X1A1 to be a very immobile vehicle.
It was not a complete failure though. The 18-ton M4 Tractor/M4 Sherman hybrid suspension would be carried over from the X1A1 to the X1A2, and the lengthened turret would also be carried over for at least the first X1A2 prototype. The X1A1 would, due to the significant problems, be the only vehicle in the X1 family that was lengthened this way with the M3/M3A1 Stuart as its basis. The X1A1 functioned more as a technology bridge between the X1 and the X1A2 than anything else. It was a useful unsuccessful project.
Specifications CCL X1A2
Dimensions (L-W-H)
7.06 meters (23.2 feet) long including the gun x 2.4 meters (7.9 feet) x 2.45 meters (8 feet) tall
Total weight
17 to 20 tonnes (18.7 to 22 US tons)
Crew
4 (Driver, Co-driver, Commander-Loader, Gunner)
Propulsion
Scania-Vabis DS-11 A05 CC1 6-cylinder in-line 256 hp diesel engine
Front (Upper Glacis) 38 mm (1.5 inch) at 17º
Front (Middle Glacis) 16 mm (0.6 inch) at 69º
Front (Lower Glacis) 44 mm (1.7 inch) at 23º
Sides 25 mm (1 inch)
Rear 25 mm (1 inch)
Top 15 mm (0.6 inch)
Floor 13 to 10 mm (0.5 to 0.4 inch)
Turret
28 mm (1.1 inch) all round
15 mm (0.6 inch) turret top and gun shield
Production
1 Prototype
Special thanks to Expedito Carlos Stephani Bastos, the leading expert in Brazilian vehicles, please visit his website for further reading on Brazilian vehicles: https://ecsbdefesa.com.br/, Jose Antonio Valls, an Ex-Engesa employee and expert in Engesa vehicles, Paulo Bastos, another leading expert of Brazilian Armored vehicles and the author of the book on Brazilian Stuarts and the website https://tecnodefesa.com.br, Adriano Santiago Garcia, a Captain in the Brazilian Army and ex-company commander on the Leopard 1 and ex-lecturer on the Brazilian Armored School, and Guilherme Travassus Silva, a Brazilian with whom I was able to endlessly discuss Brazilian Vehicles and who was always willing to listen to my near endless ability to talk about them.
Sources
Brazilian Stuart – M3, M3A1, X1, X1A2 and their Derivatives – Hélio Higuchi, Paulo Roberto Bastos Jr., Reginaldo Bacchi
Blindados no Brasil – Expedito Carlos Stephani Bastos http://www.lexicarbrasil.com.br/
Personal correspondence with Expedito Carlos Stephani Bastos
Personal correspondence with Paulo Roberto Bastos Jr.
Engesa brochures and manuals
Cockerill brochures
TM 9-785 18-Ton High Speed Tractors M4, M4A1, M4C, and M4A1C – US Army April 1952. Stuart: A history of the American Light Tank, Volume 1 – R.P. Hunnicutt
Tecnologia Militar Brasileira magazine
Federative Republic of Brazil (1971-1975/1976)
Reconnaissance Vehicle – At Least 9 Built + 102 Ordered
Up until 1967, Brazil was dependent on foreign countries for armored vehicles. Throughout and in the aftermath of World War 2, Brazil received large numbers of cheap surplus armored vehicles from the United States, including the M3 Stuart and the M4 Sherman, as it had entered the war on the Allied’s side in 1942. In fact, Brazil had not undertaken any tank design since 1932, and those had only been conversions of tractors and cars into armored vehicles during the revolutions of 1924, 1930, and 1932.
Between 1932 and 1958, the Brazilian Armed Forces created a solid basis of technical institutes from which it could educate technical and research personnel. In turn, these helped the Brazilian automotive industry in developing its own automotive parts and helped in opening laboratories for the manufacturers. In 1967, Brazil set up a plan for the country to become more militarily self-sustaining. The flow of US material had decreased because of its entanglement in the Vietnam War and, after a study, Brazil recognised external dependence on arms suppliers as a serious problem for its political position in South America.
The plan to solve this became the start of the Brazilian defense industry. After the Army had remotorised various vehicles, such as the M8 Greyhound, with diesel engines, they set off developing Brazil’s first wheeled vehicle with serial production in mind. The 4 x 4 VBB-1 which resulted from this development was everything but revolutionary. It did provide the needed experience and confidence for the Brazilian engineers though. With the rejection of the VBB-1 because the Army wanted a 6 x 6 vehicle, Brazilian engineers started developing the vehicle which would become the most successful armored fighting vehicle Brazil ever developed: the EE-9 Cascavel.
Genesis
The story of why the EE-9 Cascavel (English: Rattlesnake) was developed can be traced back to the Second World War. Brazil sent an expeditionary force, known as the Smoking Snakes, to fight in Italy alongside the Allies. During the Italian Campaign, the Brazilian forces were armed with US M8 Greyhounds. The M8 Greyhound turned into the most loved vehicle by the Brazilian soldiers, and after WW2, this love would remain embedded in the Brazilian Army. The positive experience with the M8 during WW2 caused it to be the most impactful vehicle for the Brazilian development of armored vehicles. As a result, most of the wheeled vehicles and the wheeled vehicle program can trace back their roots to the M8 Greyhound during the Italian campaign. This love for the M8 resulted in the development of Brazil’s EE-9 Cascavel some 25 years after WW2, a heavily improved and altered concept of the M8 Greyhound.
Although Brazil enjoyed its diplomatic relations with the United States well into the 1970s, the first steps to break free from the United States, from an Army materiel point of view, started in 1967. The United States got increasingly involved with the Vietnam War and, as a result, could not supply Brazil with the cheap equipment it once did. This severely undermined Brazil’s political power in South America. Not only were they seen as a United States proxy state, now with the military ties effectively cut loose, Brazil had no way to fight a prolonged war with its neighbors.
The Brazilian Army conducted a study regarding its dependency on the United States in 1967, which resulted in the Triennial Plan 68/70. The Brazilian Army recognized its external dependence as a serious issue and advocated for the encouragement of R&D (Research and Development) of locally designed and produced materiel. This would in turn cause the Diretoria General de Material Bélico (DGMB) (English: General Directorate of War Material) to further study armored equipment from all over the globe, with 4 x 4 and 6 x 6 vehicles in particular. By studying the wheeled vehicles of the United States, the United Kingdom, Belgium, Switzerland, the Netherlands, and Italy at the time, the DGMB called for the intensive adoption of wheeled armored vehicles. These vehicles required a relatively modest investment for their development, and as such, were more viable to develop instead of importing them. The study proposed the creation and adoption of a vehicle like the M8 Greyhound, but simpler.
PqRMM/2
From this point onward, the Parque Regional de Motomecanização da 2a Região Militar (PqRMM/2) (English: Regional Motomecanization Park of the 2nd Military Region) started taking the first steps towards developing armored vehicles for the Army. The PqRMM/2 was a group of army automotive engineers gathered to study, develop and produce armored vehicles in Brazil, and were the pioneers of the Brazilian defense industry.
The first step the PqRMM/2 team undertook was the motorization of Brazil’s M8 Greyhounds and M2 half-tracks with locally produced diesel engines. With the success of these projects, they continued to the next phase of the program and developed Brazil’s first wheeled vehicle with serial production in mind. The Viatura Blindada Brasileira 1 (VBB-1) (English: Armored Car of Brazil 1) was a 4 x 4 vehicle meant for reconnaissance and mounted a copy of the M8 Greyhound turret. The VBB-1’s concept came from the Belgian FN 4RM 62F, but its design was based on the M8 Greyhound. Although the VBB-1 seems to have successfully performed its tests when the vehicle was presented to the Army in 1969, the Army did not want a 4 x 4. It was briefly considered by the engineers to cut the hull in half and lengthen it to accommodate a 6 x 6 suspension, but the idea was almost immediately rejected, as the development of a new vehicle was deemed more effective.
Why the PqRMM/2 engineers developed a 4 x 4 for the Army in the first place is a bit strange, considering they knew that the army wanted a 6 x 6 like the M8 Greyhound. Nevertheless, the VBB-1 would lay the groundwork for the research of the 6 x 6 vehicle. Some components were carried over from the VBB-1 to the upcoming 6 x 6, such as the turret and engine. By starting from scratch, the team could implement all the lessons they learned from the VBB-1 project and thus get a better basis for future developments.
The VBR-2
For the development of the Viatura Blindada de Reconhecimento 2 (VBR-2) (English: Armored Reconnaissance Vehicle), the PqRMM/2 team followed the specifications of the Diretoria de Motomecanização (DM) (English: Directorate of Motomechanisation). The VBR-2 was pretty much a Brazilian copy of the M8 Greyhound. A single metal mock-up of the VBR-2 was made by the PqRMM/2 in early 1970.
Its overall shape was almost identical to the M8, with the raised hull construction for the driver being one of the most notable features. The hull construction was a bit more simplified though, with more flat plates like the VBB-1, but without some of the complicated shapes of the VBB-1. It mounted the same turret as the VBB-1, which was a copied M8 Greyhound turret but with a closed top. It was armed with a 37 mm cannon and a .50 cal machine gun.
The engine deck style also resembled the M8’s and came from the VBB-1 design as well. Considering the overall design features, it can be expected that the rear of the VBR-2 would also look like the M8, considering the VBB-1 and the later EE-9 Cascavel rear all share the same design.
The CRR
The VBR-2 mock-up underwent various redesigns together with a redesignation to Carro de Reconhecimento sobre Rodas (CRR) (English: Wheeled Reconnaissance vehicle). The hull underwent some geometric redesigning, causing the vehicle to look less like a box because of the more angled side plates. Another difference in the hull design, which enabled the hull to receive an improved ergonomic design, was the redesign of the driver’s raised hull construction.
The VBR-2 had a raised construction that extended towards both sides of the hull to provide vision for both the driver and co-driver much like the M8 Greyhound. The raised hull construction was now located in the middle of the hull on the CRR and did not extend to both sides of the hull. This meant that the CRR did not have a co-driver, which reduced the crew to 3.
Another important step in the development of the CRR was the installation of the Boomerang suspension from Engenheiros Especializados SA, better known as Engesa. Engesa had previously modernized and delivered new trucks for the Brazilian Army with their Total Traction system. This patented traction system was the key for Engesa in the defense industry, mainly because it was identified as a system ‘of interest to National Security’ by the Army. Engesa also participated in the VBB-1 project by supplying the transfer box. With the VBR-2 built, the PqRMM/2 team sought a better suspension system for the 6 x 6 vehicle and found it in an invention from 1969.
The Boomerang Suspension
In 1969, Engesa invented the Boomerang suspension. The suspension was invented to enable trucks to transport oil from difficult terrain with bad infrastructure to the refineries. With this suspension, the trucks could traverse otherwise untraversable hills for conventional suspension systems, as the wheels would always stay in contact with the ground to provide maximum traction.
The suspension system was a two wheeled-single axle driven suspension. The advantage of the boomerang suspension was that it could be fitted on existing differentials with a single axle. Normally, this meant that the single axle, designed for the torsion forces of a single wheel, was subjected to the torsion forces of two wheels. Through excellent engineering, half of the torsion forces of the two wheels were mitigated by the suspension system built around the original axle. This design not only enables the drive of two wheels by a single axle but with clever usage of gears and bearings on both the axle and tube around the axle, the suspension system can rotate around its axle for 360 degrees. This ability to rotate in extreme angles would enable the vehicles to traverse very difficult terrains and still provide maximum traction, as the suspension system curved with the terrain so that all the wheels were always in contact with the ground.
Engesa
Engenheiros Especializados SA, or Engesa, was the largest and the most famous company in the Brazilian armored vehicle industry. Engesa was founded in São Paulo in 1958 by José Luiz Whitaker Ribeiro. Initially, Engesa focused on oil prospecting, production, and refinement equipment. With the invention of Engesa’s total traction suspension system, they were hired to modernise and build trucks for the Brazilian Army.
In 1969, Engesa introduced its flagship boomerang suspension for its wheeled vehicles. Only a single axle was needed to drive the 4 wheels which were in constant contact with the ground, providing constant traction. At the time, this was a simple, sturdy, and relatively cheap construction. Although not fit for heavy vehicles, it was perfect for the armored vehicles that Engesa would start to manufacture in the near future.
With Engesa’s involvement in refitting the Army’s trucks with the Total Traction system and the development of their Boomerang suspension, they were contacted by the Army to help develop the wheeled vehicles together with the PqRMM/2 team. This joint development resulted in the EE-9 Cascavel and the EE-11 Urutu. The EE-9 Cascavel paved the way for Engesa to take its position as the leading company of the Brazilian Defense Industry.
The Cascavel is Born
With the installation of the boomerang suspension and the redesign of the hull, the basis was laid for what would become the EE-9 Cascavel. The mock-up of the CRR was built in early 1970 and presented to General Plínio Pitaluga, a veteran of the FEB. It seems that, almost immediately after the mock-up was finished, the PqRMM/2 engineers started the production of the first working prototype.
Nearing the end of the construction of the CRR prototype, a new turret was developed for the new 6 x 6 vehicle. The CRR mounted a redesigned VBB-1 turret with a turret bustle. The VBB-1 turret was a copy of the M8 Greyhound turret and was manufactured by Fundições Alliperti S/A and Avanzi. It is noted that the redesigned VBB-1 turret was manufactured by Companhia Siderúrgica Nacional (CSN) (English: National Steel Company). Although the CRR received the redesigned VBB-1 turret, the original plan was to mount copied and redesigned M3 Stuart turrets with an added turret bustle, which were also produced by CSN. But, by the time the CRR prototype was finished, the redesigned M3 Stuart turrets were not ready yet.
The prototype of the CRR was completed in 1971. It used a copied and redesigned M8 turret armed with a 37 mm cannon and a .50 machine gun on top of the turret. The turret was a fully enclosed turret designed by Engesa. The vehicle-mounted run-flat tires were previously developed by Novatracão for the VBB-1 project. The vehicle’s exhaust was located on the right side of the rear. The vehicle had a crew of 3. The driver was positioned in the middle of the hull and had a raised structure for his head and the sights. The remaining two crew members were the gunner and the commander/loader.
The CRR was extensively tested by the Brazilian Army, tests which were overseen by the PqRMM/2. During the tests, the CRR prototype travelled over 65,000 kilometers and performed various mobility tests. The tests were successful, as the construction of a 5 vehicle pre-series was approved. The number of pre-series vehicles would increase to a total of 8 vehicles after the Diretoria de Pesquisa e Ensino Técnico do Exército (DPET) (English: Army Directorate of Research and Technical Education), which oversaw the PqRMM/2 developments, signed a contract with Engesa in June 1971 for the development and construction of the pre-series. Production of the 8 pre-series vehicles for the Brazilian Army began in 1972 and was finalized in September 1975.
With the signing of this contract, the CRR was officially carried over to Engesa. What is interesting is that the Brazilian Army, despite having developed the CRR, signed off all their intellectual property rights to Engesa. This effectively meant that the Brazilian Army itself would not directly profit from any sales of the future EE-9 Cascavel to other countries. This transfer to Engesa also meant that the CRR would be marketed as the EE-9 Cascavel.
The Snake Family
The EE-9 Cascavel was part of a family of wheeled vehicles, all named after snakes found in Brazil. These vehicles were the EE-3 Jararaca, EE-9 Cascavel, EE-11 Urutu, and EE-17/18 Sucuri, meaning jararaca, rattlesnake, crossed pit viper, and anaconda, respectively.
The EE-3 was a 4 x 4 reconnaissance vehicle that could mount a wide range of turrets. The EE-9 was Engesa’s reconnaissance vehicle, but due to its mobility and the 90 mm cannon, it would be employed in all kinds of roles. The EE-11 was a troop transport but could be configured to perform all sorts of specialised roles, like Anti-Aircraft, mortar carrier, and ambulance. The EE-17 and EE-18 Sucuri were two 105 mm armed 6 x 6 wheeled tank destroyers.
The EE-9 was effectively the flagship of this family, even though Engesa thought the EE-11 would be their most successful vehicle. The EE-11 was successful nevertheless, but the Jararaca and the Sucuri were less of a success. The Jararaca was sold in very limited numbers, while the Sucuri was not even sold at all.
Cascavel Designations
With the transfer of the CRR to Engesa also came a new designation. The exact date of when the CRR was designated as EE-9 is unknown. But it is estimated to have been named EE-9 between 1972 and 1973, with EE referring to Engenheiros Especializados (English: Specialized Engineers) and the 9 to its weight in tonnes. The interesting part is that practically every Cascavel exported by Engesa weighed more than 10 tonnes empty. As such, the 9 in EE-9 refers to the 37 mm version of the Cascavel. The weight in a brochure, which is estimated to have been written between 1973 and 1974, refers to the Cascavel with a 37 mm gun as having a 9 tonnes combat weight.
The CRR was redesignated by the Army as well, with the completion of the pre-production batch, to Carro de Reconhecimento Médio (CRM) (English: Medium Reconnaissance Car). This designation is more of a vehicle classification, like the CRR, than a name. This effectively means that the prototype CRR, the pre-production CRM, and the production vehicles were all known and sold as EE-9’s.
What is interesting, is that Engesa seems to have skipped designating an M1 Cascavel, and immediately built M2 hulls after the CRM. It might be that the 37 mm Cascavels were unofficially seen as first production versions, but through hull classification were simply branded as M2’s.
Since the EE-9 Cascavel was built and developed for 18 years, it received upgrades and design changes over time. To keep track of these changes, a so-called Modelo or Model system was used. It is important to note that different guns or turrets did not mean that the Cascavel was a different model. The Cascavel M2 for example, used all three 90 mm turrets offered by Engesa (HS-90 turret with the French D-921 gun, ET-90 I turret with EC-90 gun, and the ET-90 II turret with EC-90 gun). It was mainly changes to the hull, and especially the transmissions, which caused the Cascavels (Portuguese: Cascavéis) to be classified as a certain model. The Modelos were then further subdivided in production batches or Séries. The differences between the series could be as small as different bolts or different tyre nozzles. The development of the Cascavel was a process of evolution, and certain manuals would be written specifically for a range of series of a certain model.
The enthusiast’s guide to Engesa’s Cascavel galaxy
Model
Charatistics
Date
Sold numbers by Engesa
CRM
The pre-production EE-9 with a manual Clark 280V transmission and a 37 mm gun, practically an improved M8 Greyhound.
1971
8
EE-9 M2
Interestingly, Engesa seems to have skipped designating a Cascavel with the M1 designation. As a result, the production Cascavels with 37 mm guns are also M2’s.
The first EE-9 to have a 90 mm gun as its main armament. Overall hull redesign, larger dimensions of the hull to mount the new 90 mm armed turrets. Used a manual Clark 280V Transmission
1974
Brazil: 157 of which at least 9 were originally armed with 37 mm.
Bolivia: 24
Chile: 83
Libya: 200
EE-9 M3
Effectively an M2 Cascavel, but with an automatic MT-540 transmission (the first Cascavel model with an automatic transmission). The first Cascavel model to receive the EC-90 gun.
1975
Libya: 200
EE-9 M4
The M4 was specifically designed, built and sold with the Detroit Diesel 6V53 engine. Overall strengthening of components and further evolution of the hull design. It used an MT-643 transmission.
1979
Brazil (CFN): 6
Colombia: 128
Cyprus: 124
Iraq: 364
EE-9 M5
Used the M4 design but was a cheaper version. It was sold with either an AT-540 or AT-545 transmission in combination with the OM-352A engine.
1981
Bovington Tank Museum: 1
Gabon: 14
Uruguay: 15
EE-9 M6
Automotive enhancements over the previous models. Used the AT-545 in combination with the OM-352A engine.
1982
Brazil: 37
EE-9 M7
The same as the M6, but used an MT643 transmission. This Cascavel was the final model designed by Engesa. It could mount every engine which Engesa sold with the Cascavel, although it only seems to have been used with the OM-352 and the OM352A engines.
Total: around 1,742 sold and less than 1,800 produced.
Arming the EE-9 Cascavel
In 1972, with the start of the construction of the pre-production Cascavels, came the discussion of what the future reconnaissance vehicles of the Brazilian Army should be armed with. Up until then, the reconnaissance doctrine of the Brazilian Army had not changed since their experiences in World War 2, and this old doctrine was still somewhat ingrained in the Army.
An analysis regarding the specifications for a reconnaissance vehicle was released on July 10th 1967. The requirements called for a vehicle which could penetrate its own armor at ranges up to 1,000 meters, fire in all directions (have a turret), a rate of fire of at least 3 shots per minute, and the armament did not have to be used for anti-air purposes. The issue with these requirements is that practically every gun of 20 mm and higher could perform this job.
With the initiation of the VBR-2 project, a discussion emerged within the Army. Recommendations were gathered on what to arm the coming generation of reconnaissance vehicles. The issue was that the Armies (plural) of Brazil, generals, and departments gave conflicting advice about what to arm the vehicle with. Aside from this, the Army also had to take export potential into consideration for Engesa. Since the Brazilian Army completely handed over the project to Engesa, they also wanted to keep logistics and profit for the company as advantageous as possible. By the end of 1972, the Brazilian Army had selected two ranges of potential cannons: 20 to 40 mm or the 90 mm. The Army referred to the FV107 Scimitar for the lower caliber cannons, potentially suggesting that they wanted an autocannon on the Cascavel, and not the 37 mm which they had used so far.
With the selection of the two ranges, a new discussion came at the forefront regarding the purpose of the reconnaissance vehicle. It was recognized that less than 4% of the missions performed by cavalry units during World War 2 were pure reconnaissance missions. The question then was which role would the future Cascavel perform the most and which of these guns was the most suitable. The 90 mm would perform best for anti-tank missions, while the 20 to 40 mm range would be more fit against personnel and overall perform an infantry fighting vehicle role, without being able to carry infantry. It was identified that the EE-9 would not be fit to fill the Infantry Fighting Vehicle role as it did not have the armor to reliably perform this role. At the same time, it was recognized that a 90 mm gun would give the Cascavel a better fighting chance against potential enemy armor. The reasoning was mainly from an isolation point of view, in which a Cascavel on a reconnaissance mission had to fend for itself and take out potential enemies, like tanks. It was determined that the 90 mm was the most suited for this role, considering most of Brazil’s neighbours operated the Shermans as their heaviest armored vehicles at the time, and employed a large number of AMX-13’s and SK-105’s as their other combat tank.
It took up to the second half of the 1970s for the Brazilian Army to completely make up its mind on which cannons should be used on the Cascavel. When this discussion still raged in 1977, the Cascavel with 90 mm gun was already used by Libya against Egypt, and multiple countries ordered the 90 mm cannon.
What might have steered the Brazilians towards eventually deciding to operate a 90 mm Cascavel only force were the trials in Portugal in 1973. Portugal was still in the War of Ultramar as it tried to maintain its colonial empire. Among the vehicles the Portuguese used to fight their opponents was the AML-90. The AML-90 was a 4 x 4 armored car which could be used for reconnaissance and was armed with the potent D-921 90 mm gun.
The Portuguese were approving of the EE-9 Cascavel, which boasted better mobility than their AMLs, but suggested that Engesa should retrial the vehicle when it was armed with the French D-921 gun. As a result, the Brazilian Army ordered the turrets and guns for both the single EE-9 of Engesa and the X1 tank program as well. Engesa retrialled the EE-9 in early 1974, but would not manage to sell the vehicle, as the Portuguese government was overthrown and the War of Ultramar ended. The Engesa team decided to pack up their vehicles and head straight to Libya, where they managed to secure a deal for 200 EE-9 Cascavels armed with 90 mm guns.
From this point on, an increasing number of countries started ordering the 90 mm Cascavel, and it is thought that the popularity of the 90 mm gun, in combination with the performance of the 90 mm gun, caused the Brazilian Army to finally opt for the 90 mm armed Cascavel.
Armoring the EE-9 Cascavel
Until 1968, armor studies were practically non-existent in Brazil. There had been some brief attempts during the revolutions of 1924, 1930, and 1932, but these were mainly of improvised nature. With the initiation of national armored vehicle development also came studies on what to armor the upcoming armored vehicles with. The PqRMM/2 team started off by evaluating all the steel compositions of the vehicles which were acquired by the Brazilian Army over time. The team discovered that the homogenous steel plate of the M2 Half-Track had been heat-treated on the outer side to provide a harder surface, while providing a more ductile surface on the inside to prevent shattering.
The team determined that the effort needed to carry out the necessary techniques for hardening was only justifiable for mass production. With mass-production of the future armored vehicles being expected, the team decided that the development of a dual-hardness plate or bimetal armor would be viable. This type of steel was previously developed in Sweden in 1930 and was known as duplex steel. It would find its first extensive usage on armored vehicles in Brazil. The main difference from other examples of face hardened armor is that two plates of varying carbon content were welded together in production to form a bimetal plate instead of bolting on a hardened plate afterward.
The steel for the bimetal plates was provided by Eletrometal and Usiminas. With Eletrometal providing the high-carbon outer plates and Usiminas the medium-carbon plates. The plates were joined, with 25% of the total plate thickness being high-carbon steel and 75% medium-carbon. The plates were laid on top of each other and subsequently welded around the edges. The bimetal plates were then forged together from 65 mm to about 30 mm thickness and then hot-rolled to the required thickness, This was followed by a quench, tempering, and hardening to the desired hardness. The high-carbon plate was hardened to 700 Brinell while the medium-carbon plate was 250 Brinell.
The average effectiveness of the bimetal plates was about 1.8 times the thickness of an equivalent homogeneous plate against 7.62 mm or 1.5 times the thickness against .50 machine gunfire. This meant that, against .50 machine gun fire, a 16 mm bimetal plate could be used instead of a 25 mm homogenous steel plate. These protection advantages over homogenous plates effectively meant that the Cascavel saved a lot of weight without compromising protection. The outer layer would shatter and blunt the incoming projectile, while the inner layer would relatively move with the bullet, slowing it down and stopping it without shattering.
An interesting tidbit of information according to an ex-Engesa employee who worked at the tempering station was that, at some point, the armor did not perform according to standards. It turned out that the tempering oven was not maintained properly, and the temperature control was faulty. This issue would remain for a few years until it was finally resolved. In order to keep building the armored vehicles, a lot of these plates were approved by quality check anyway, despite being faulty.
Trials in Portugal
In early 1973, Engesa trialled their vehicle in Portugal in an attempt to export it. As previously mentioned, Portugal was fighting against its uprising colonies in the War of Ultramar, also known as the Overseas War in English. At the time, the Portuguese Army was operating a mix of AML-90 and Panhard EBR armored cars in Africa. The Portuguese were impressed by the EE-9 Cascavel, which at that time was most likely still in its CRR configuration, but they suggested that Engesa should arm the Cascavel with the same turret and gun as the AML-90 and return to trial the vehicle again.
With Engesa wanting to arm the Cascavel with a 90 mm gun, the Brazilian Army opted to go for the 90 mm gun on the X1 project as well. They bought 53 turrets and guns from the French company SOFMA. Most of these turrets were ditched, as they did not meet the protection requirements of the Brazilian Army, and local turrets were designed and built as a result. Engesa would arm the EE-9 sent to Portugal with the French turret, but also developed their own turret.
The EE-9, most likely with the M2 hull design to solve some practical issues of the CRR configuration, and mounting an HS-90 turret and armed with a D-921 90 mm gun, was trialed again in early 1974. This EE-9 trialed in Portugal could be counted as being the first 90 mm armed EE-9 M2 Cascavel. The problem is that these designs were made before the later production variant of the EE-9 was known to have been built around 1975. For this reason, these projects will be seen as prototypes for both the 90 mm armed EE-9 M2, because of its armament, and as prototypes for the 37 mm EE-9 M2 because of the likely redesigned hull. Portugal would not acquire the EE-9 M2 because a Coup d’Etat put an end to the War of Ultramar.
The influence of Portugal in the success of the EE-9 should not be understated. After the failed attempt to sell the EE-9 Cascavel to the Portuguese, the Engesa team loaded the Cascavel and Urutu back in their freighter and set course to Libya. There, the EE-9 M2 would find success and manage to secure a deal for 200 Cascavels. This deal brought the necessary cash for Engesa to buy a large production plant, and by 1975, the first production Cascavels started rolling from the production line.
The request of the Portuguese to arm the EE-9 with a 90 mm gun effectively helped Engesa to secure a deal with Libya, which would eventually use the Cascavel in combat, generating more sales and making the Cascavel the success it was. At the same time, Brazil also started the development of locally produced turrets for the 90 mm guns for both the Cascavel and X1.
90 mm Turret Designs on the CRR hull
The switch from 37 mm towards the 90 mm would normally mean that the EE-9 Cascavel is an EE-9 M2. These projects were specifically designed on the early CRR hull or on a hybrid between the CRR and the pre-production vehicle which would be designated as Carro de Reconhecimento Médio (CRM) (English: Medium Reconnaissance Car). The problem is that these designs were made before the production vehicle of the EE-9 was built. For this reason, these projects will be seen as prototypes for both the EE-9 M2, because of their armament, and as prototypes for the 37 mm armed EE-9 M2, because of the hull. There were two designs: a CRR/CRM hybrid mounting the copied and lengthened M8 turret and armed with a 90 mm gun and a CRR with the French turret.
The CRR with HS-90 turret
The Brazilians made a design with the CRR hull mounting an HS-90 turret. This design was effectively the predecessor of the EE-9 M2 Cascavel. The HS-90 turret was ordered from France and had to be bought as a full package, including the D-921 gun. This Cascavel would have had a gun depression of 8 degrees and an elevation of 15 degrees. Aside from the 90 mm gun, it was also armed with a coaxial 7.62 machine gun. In addition to its armament, it would also be armed with 3 smoke launchers on each rear side of the turret. It could mount a turret top machine gun, night vision sights, radio and intercom, laser rangefinder, and an extra ammunition stowage as optional equipment. It is stated that the EE-9 sent to Portugal used this turret, but it is unlikely that the CRR hull was used for these trials.
The reason for this is that the HS-90 turret would not only be too big for the hull and come in collision with both the driver’s vision structure, but also with the engine bay covers. On top of that, the driver’s vision structure would make it virtually impossible to depress or even fire the gun on a flat angle. As such, it seems that the drive for the 90 mm turret caused the hull to be redesigned to resolve these issues.
The CRR/CRM Hybrid M8 Copy Turret
Another of the designs was effectively a hybrid between the CRR and the later CRM production vehicle. The main hull design change which hints towards it being a hybrid design is the altered headlight guard. On the CRR, the headlight guard was a simple square design, while in this design, it was curved, like on the CRM.
In addition, the copied M8 turret also received some changes which would be seen in the turret later used on the pre-production CRM. Compared to the original CRR turret, this turret had a ventilation inlet on the top of the turret and the antenna, which was originally on the left rear side of the hull, has now been installed on the turret as well. Apart from these 2 features, the turret also provided periscopes for the gunner, apart from the direct sight in the gun mantlet. The 90 mm gun would have a depression of 8 degrees and an elevation of 13 degrees and be installed in a turret with a turret diameter of 1.6 meter. It could mount a turret-top machine gun for anti-aircraft purposes.
In addition, a Perkins type 6357 6 cylinders in-line 142 hp diesel engine, along with a Chrysler type 318 HD V8 196 hp diesel engine, were offered. But Engesa also offered to fit in other engines, depending on the customer’s needs. It would use a 6-speed manual gearbox with five speeds forward and one in reverse. It would have been protected from the front with bimetal armor, protecting against .50 machine gun fire and from the sides from 7.62 mm fire. The exact weight and speed of this design are unknown but are estimated at around 10 to 11 tonnes and 95 km/h, depending on the engine selected.
The CRM
By September 1975, the production of the pre-series of 8 vehicles, known as the CRM, was finished. The pre-series hulls still carried over much of the design of the CRR hulls. The CRM can be easily identified and distinguished from the CRR in two ways. The first is the redesigned headlight guards, which were now curved instead of simple squares. The second is the relocation of the antenna and most likely the radio set as well. On the CRR, the antenna is located on the left rear of the hull, while on the CRM, the antenna was moved to the turret.
When the CRM was delivered, it seems that the planned altered M3 Stuart copy turrets were still not finished. As a result, the CRM received a much more modernized version of the original CRR turret. The new turret incorporated a ventilation inlet on the left rear of the turret top with the antenna and, most likely, the radio sets moved next to it on the right side. The turret structure on both the commander’s and gunner’s side was also much improved compared to the CRR. A structure was welded on both sides which integrated 2 extra sights to enable a much better overview for the crew.
The 8 vehicles were almost immediately tested after they were delivered. They had to drive back and forth for 32,000 kilometers between São Paulo to Alegrete. The CRM’s drivo 24/7 and only stop for fuel or if maintenance was needed. The CRM’s seemed to have performed well during these trials, as the CRM, and thus the EE-9 Cascavel, was accepted into service. 102 production vehicles were ordered by the Brazilian Army, all armed with the 37 mm gun.
A Bid for a National Turret
It seems that, around this time, a bid was opened by the Brazilian Army for a locally designed and produced turret to be mounted on the EE-9 Cascavel. Interestingly, of the pictures available, Bernardini built a turret with a 37 mm cannon, while Engesa had the turret with a 90 mm gun which was originally mounted on the X1 prototype. It is very likely that Bernardini also offered the 90 mm turret, as the 37 mm turret was effectively the production turret of the X1, but rearmed with a 37 mm cannon. It is unknown if Engesa built and offered a 37 mm turret. Both of these proposals were built on CRM hulls.
Bernardini’s Entry
As previously stated, Bernardini would have most likely entered the competition with both the 37 mm turret and the 90 mm turret. The turret which Bernardini offered was the production turret of the X1, which was designated BT-90A1. The Brazilian Army had previously bought 53 HS-90 turrets and D-921 90 mm guns. The issue was that the turret armor of the HS-90 was insufficient for the requirements of the Centro de Pesquisa e Desenvolvimento de Blindados (CPDB) (English: Center for the Research and Development of Tanks). As a result, Bernardini and the Brazilian Army started developing a local turret that was armored with 25 mm thick plates to protect the X1 from .50 cal machine gunfire. The design of the BT-90A1 turret was heavily inspired by the HS-90 turret, with the first prototype of the turret (BT-90) even using some components of the HS-90 turret. The main differences between the HS-90 and the BT-90A1 were the addition of a gun shield on the BT-90A1, improved armor, and the BT-90A1 overall being more bulky than the HS-90. The main difference between the 37 mm and the 90 mm turrets from Bernardini was that the 37 mm turret received a new gun shield and was altered for the 37 mm armament.
Engesa’s Entry
Engesa’s design was the turret which was briefly mounted on the X1 prototype. The turrets differed in a very minor way. The rear sides of the Engesa turret, on which the most rearward smoke launcher was installed, went inwards instead of being a flat plate. It is unknown if this turret used bimetal armor or not. The vehicle was armed with a 90 mm gun and a coaxial 7.62 mm machine gun. In addition to its armament, the turret also mounted 2 pairs of 3 smoke grenade launchers on both sides of the rear turret.
Who Won?
It is unclear which company won this specific bid, as both the Engesa turret and the Bernardini turrets were never mass-produced. Interestingly however, in a platoon manual for mechanized units from 1977 (the first of its kind in Brazil), an EE-9 is presented with the Bernardini turret. The EE-9 was called: CBR MB-1 Cascavel. The MB-1 referred to the Bernardini turret and was armed with the French D-921 cannon.
What seems to have happened, was the switch from the D-921 gun to the license-produced EC-90 gun, which was based on the Cockerill 90 mm gun. Somewhere between 1975 and 1976, Engesa got a licensing deal with Cockerill for their 90 mm gun. This was an essential shift, as the forced purchase of both turret and gun from the French became increasingly expensive, and building a local turret would have been much cheaper. This turret design bid was most likely initiated around 1975 and probably ended when Engesa got the license deal in order. It is unclear if a new bid for an EC-90 armed turret was opened, but what is known is that Engesa would design the ET-90 turret which would be used on the Cascavels from that point on.
The EE-9 M2 37 mm
With the approval of the CRM by the Brazilian Army, 102 production vehicles were ordered. If these 102 vehicles were actually delivered is unclear. Pictures exist where at least 9 production vehicles, known as the EE-9 M2 Cascavel with 37 mm, are shown. According to statements from ex-Engesa employees, the order seems to have eventually been converted into an order for the 90 mm armed Cascavel M2 and the 37 mm EE-9 M2s were supposedly converted to 90 mm M2s. How many 37 mm M2’s were eventually built before the Brazilian Army switched the order is unknown. It is estimated that the Brazilian Army changed the order around 1977.
The production model differed from the CRM in a couple of ways. The most notable two were the copied and redesigned M3 Stuart turrets, which were now finally delivered, and the removal of the raised driver structure on the hull. Another very important change was the slanting of the rear hull. This was done to fix the issue of the turret bustle colliding with the engine bay covers, and enabled the usage of low-profile turrets. It is thought that the mounting of the 90 mm HS-90 turret initiated the redesign of the hull to accommodate the turret. Another change was the removal of the exhaust pipe on the right rear side of the hull. The exhaust was now mostly located inside the Cascavel, with the exhaust coming out of the right rear side of the vehicle, above the rear wheel. In essence, the EE-9 M2 was a streamlining of the CRM and mounted the final turret.
The EE-9 M2 37 mm was unofficially called ‘Cascavel Magro’, meaning Skinny Rattlesnake, while the 90 mm armed Cascavels were unofficially known as ‘Cascavel Gordo’, meaning Fat Rattlesnake.
The EE-9 M2 37 mm in Detail
The EE-9 M2 weighed 11 tonnes (12 US tons). It was about 5 meters (16.4 feet) long, 2.3 meters (7.5 feet) wide, and the height was around 2.3 meters (7.5 feet). The EE-9 had a three-man crew, consisting of the commander/loader (turret left), gunner (turret right), and the driver in the middle front hull.
Hull
The hull of the EE-9 M2 was manufactured from welded bimetal steel plates. The upper front plate was well angled at 60 degrees from vertical. The hull also features two covers which were mounted on the hull at the positions above the boomerang suspension, effectively functioning as mudguards and very minor spaced armor.
The front upper hull plate presented 16 mm (0.63 inch) of bimetal armor at an angle of 60 degrees. The sides and rear were 8.5 mm (0.33 inch) thick at varying angles, and the top and bottom hull were 6.5 mm (0.26 inch) thick. The front of the EE-9 was meant to protect from .50 machine gun fire at an unknown range, while the entire vehicle was protected from 7.62 mm AP rounds at 100 meters (109 yards), and standard 7.62 mm rounds at 50 meters (54 yards).
The EE-9 had two headlights externally mounted on top of both sides of the upper front hull plate. A rearview mirror could be mounted on both headlight guards. A black-out light was installed on the right side of the left headlight. Below the driver’s hatch was a foldable windshield, which the driver could use when driving with an open hatch. It is not completely clear in pictures, but it seems that the driver’s hatch was a two-piece hatch, with the front part being part of the upper front plate, while the back part was part of the top hull plate. The front hatch had three periscopes for the driver for 180 degrees of vision. These periscopes and other periscopes or sights would not have been active or passive night vision equipment unless the Cascavel was ordered with these devices.
A ventilation inlet was installed on both upper hull side plates, these ventilation inlets are recognizable by their frustum shape. A siren was installed behind the ventilation inlet on the right side of the vehicle. The fuel tank cap of the Cascavel was located on the left side, in the middle of the upper side hull plate. The EE-9 had a large ventilation grille on the rear of the vehicle, reminiscent of the M8, and had a rear light on both sides of the ventilation grill. The engine could be accessed through two large hatches on the hull top rear.
The driver steered the vehicle with a steering wheel and had his gear stick on his right side, and his instrument panel to his left. The acceleration pedal was located on the right side of the steering wheel, and the brake was next to the acceleration pedal on the left. On the left side of the steering wheel was the clutch pedal.
Mobility
The EE-9 M2 used the OM352 and the OM352A engines. These are both 6-cylinder inline diesel engines of which the OM352A is turbocharged. The OM352 produces 125 hp at 2,600 rpm and 353 Nm at 1,600 rpm, while the OM352A produces 172 hp at 2,800 rpm (DIN standard) and 431 Nm at 1,800 rpm. The Brazilian Army seems to have only used the OM352A engine, although it is unknown if the earliest Brazilian Cascavels might have received the standard OM352 engine to be rebuilt or replaced later on.
The M2 Cascavel had a top speed of 95 km/h (59 mph) and an operational range of 700 km (353 miles). It had a turning radius of 7.7 meters (8.1 yards) and it could ford a depth of 1 meter (3.3 feet). The Cascavel could climb a 35-degree slope, could climb a vertical obstacle of 0.65 meter (2.1 feet), cross a trench of 1.65 meters (5.4 feet), and had a ground clearance of about 0.5 meters (1.6 feet). The front-wheel could travel for 0.2 meters (0.66 feet), while the rear wheels could travel for 0.9 meters (3 feet). It used 11 X 20 run-flat tires with a diameter of 0.5 meters (1.6 feet). The EE-9 M2 had a distance between the front axle and rear axle of 2.8 meters, and a distance of 1.4 meter (4.6 feet) between the two rear wheels.
The EE-9 used a manual Clark 280V transmission with 5 gears forward and 1 in reverse. In addition, the Cascavel used an Engesa 2 speed transfer case, which allowed the Cascavel to be used in reduced and high gear. By putting the Cascavel in reduced gear, the Cascavel sacrificed horsepower for torque, making it more effective in climbing slopes. The vehicle was 6 x 6 driven, of which the rear 4 wheels were part of the boomerang suspension. The boomerang suspension, in combination with the Engesa 2 speed transfer case, enabled the Cascavel to cross challenging terrain and provide maximum traction in most situations. The power of the engine was distributed to a differential on the front side of the vehicle, and a differential in the rear. The rear differential drove the boomerang suspension with a single axle, which made the boomerang suspension such an ingenious design.
The Boomerang suspension used leaf springs for dampening. The two front wheels were used for steering. The wheels on the boomerang suspension all rotated at the same speed. The front wheels were dampened by large coil springs. The vehicle used hydraulic drum brakes, and was steered with hydraulics as well.
Turret
The turret of the EE-9 M2 was a copy of the M3 Stuart turret. The engineers lengthened the turret to fit radios in the new turret bustle. The turret had two hatches which opened in the same way as on the previous VBB-1 and CRR turrets. In front of those hatches was a machine gun mount. Both the driver and gunner had periscopes around their hatches. An antenna was located on the right rear of the turret. An openable hatch with a vision sight incorporated was installed on both sides of the turret. A basket for stowage was mounted around the entire turret bustle. The commander was located on the left and the gunner on the right.
The armor of the turret is unknown. Considering it was a copy of the M3 turret, the protection levels might have been similar. An estimate of the EE-9 M2 turret protection would be that the front would have been armored with a plate of 51 mm (2 inch) thick at an angle of about 14 degrees from vertical. The gun shield would have been 38 mm thick (1.5 inch). The sides and rear of the M3 Stuart turret were 32 mm (1.26 inch) thick, and the top was 13 mm (0.5 inch) thick.
Armament
The EE-9 M2 used a 37 mm M6 cannon as main armament. The 37 mm M6 had a total length of 2.1 meters (6.9 feet) and a bore length of 1.98 meters (6.5 feet). The 37 mm cannon was able to fire the M51 APC round with 53 mm (2.1 inch) of penetration at 455 meters (500 yards) at a 30-degree angle, and 46 mm (1.8 inch) of penetration at 915 meters (1,000 yards) at a 30-degree angle. It could also fire the M74 AP, M63 HE, and M2 canister rounds. In addition to the 37 mm cannon, the EE-9 mounted a coaxial 7.62 machine gun on the right side of the turret, and a .50 caliber M2 machine gun on top of the turret. Interestingly, some pictures show the .50 machine gun mounted on the front top of the turret, while others show the .50 machine gun mounted on the top rear.
The EE-9 M2 had access to 43 rounds of 37 mm ammunition, 400 rounds of .50 machine gun ammunition and 1400 round of .30 machine gun ammunition.
Fate
In the end, only 9 37 mm armed EE-9 M2s have been confirmed to have been built by Engesa. 102 were ordered, but it seems that the rapid developments on the export market of the EE-9 would quickly put an end to the M2 production order. By 1976, the order was probably converted to an EE-9 M290 mm order. The 37 mm EE-9 M2s were supposedly rearmed with 90 mm’s. How many 37 mm M2s were actually built and converted remains a mystery. If these 37 mm EE-9 M2’s ever were delivered to Army units and to which, is unknown. Some sources suggest that up to 50 M2s were built, but they are very vague about this number. It is at least certain that 9 were produced and were later converted to the M2 standard.
Although the 37 mm M2s did receive serial numbers, it is not known if they were operating in a unit or if they were still serving as parade vehicles. If the 37 mm EE-9 M2 was used in service, they would have served in the following mechanized platoon structure: 1 radio jeep, 4 reconnaissance jeeps, 2 EE-9 Cascavels, 1 Urutu, and 1 ammunition carrying jeep.
Conclusion
The EE-9 M2 37 mm seems to have been more of a stopgap than anything else. Although the Brazilian Army wanted the 37 mm armed EE-9 M2, debates within the Army were already heading towards either an autocannon or a 90 mm cannon-armed Cascavel. It was at least quite clear from the start that the rest of the world wanted the 90 mm Cascavel. Considering the EE-9 M2 was already ordered by Libya, the M2 37 mm was already outdated before it was even put into production for the Brazilian Army. Eventually, the Brazilian Army folded towards the 90 mm, and made the decision definitive when Engesa could build their own turrets instead of importing them.
As such, the 37 mm EE-9 M2 itself was an excellent platform with an outdated turret. The Portuguese recognized the capabilities of the EE-9 and were the ones to give the nudge to Engesa to go forward and arm it with a 90 mm. The 37 mm was an armament of the past, while the boomerang suspension and the bimetal armor provided excellent mobility in combination with protection. The Brazilians had succeeded in building their improved version of the M8 Greyhound and established the groundwork for what became Brazil’s most-produced armored fighting vehicle of all time.
Illustrations
Specifications EE-9 M2 37 mm
Dimensions (L-W-H)
5 meters x 2.3 meters x 2.3 meters (16.4 feet x 7.5 feet x 7.5 feet)
Front 16 mm (0.63 inch)
Side 8 mm (0.32 inch)
Rear 8 mm (0.32 inch)
Top 6.5 mm (0.26 inch)
Floor 6.5 mm (0.26 inch)
Turret
Front 51 mm (2 inch)
Gun mantlet 38 mm (1.5 inch)
Sides 32 mm (1.26 inch)
Rear 32 mm (1.26 inch)
Top 13 mm (0.5 inch)
Production
At Least 9, up to a hundred
Special thanks to Expedito Carlos Stephani Bastos, the leading expert in Brazilian vehicles, please visit his website for further reading on Brazilian vehicles: https://ecsbdefesa.com.br/, Jose Antonio Valls, an Ex-Engesa employee and expert in Engesa vehicles, Paulo Bastos, another leading expert of Brazilian Armored vehicles and the author of the book on Brazilian Stuarts and the website https://tecnodefesa.com.br, Adriano Santiago Garcia, a Captain in the Brazilian Army and ex-company commander on the Leopard 1 and ex-lecturer on the Brazilian Armored School, and Guilherme Travassus Silva, a Brazilian with whom I was able to endlessly discuss Brazilian Vehicles and who was always willing to listen to my near endless ability to talk about them.
Sources
Engesa EE-9 Cascavel 40 anos de combates 1977-2017 – Expedito Carlos Stephani Bastos
Ford M-8 Greyhound Exército Brasileiro – Surge o conceito de blindado 6×6 – Expedito Carlos Stephani Bastos
Blindados no Brasil – Expedito Carlos Stephani Bastos
Brazilian Stuart – M3, M3A1, X1, X1A2 and their Derivatives – Hélio Higuchi, Paulo Roberto
Bastos Jr., Reginaldo Bacchi
Engesa manuals
Engesa brochures http://www.lexicarbrasil.com.br/
Dual Harness skin stops armor-piercing projectiles Article of Richard M. Ogorkiewicz
Sipri Arms Transfer Database
Personal correspondence with Ex-Engesa Employees
Personal correspondence with Expedito Carlos Stephani Bastos
Personal correspondence with Paulo Roberto Bastos Jr.
Personal correspondence with Adriano Santiago Garcia
Federative Republic of Brazil (2012)
Multi-Purpose Wheeled Armored Personnel Carrier Platform – 500+ Built (10 For Lebanon), 1,580 Planned (28 For The Philippines and 11 For Ghana)
In 1999, the Brazilian Army initiated a study to replace the EE-9 Cascavel and EE-11 Urutu, which were successful projects during the 70s and 80s. By the late 1990s, these vehicles were nearing 25 years of service and becoming obsolete. This obsolescence was confirmed in the peacekeeping missions carried out in the 1990s by the Brazilian Army for the UN in Mozambique and Congo and in the missions in Haiti carried out in the 2000s. Urban combat experiences there exposed the flaws and shortcomings of the EE-9 and the EE-11, causing the vehicles to undergo various overhauls and maintenance.
Due to the lessons learned from the peacekeeping missions, the Brazilian Army decided to create a new armored vehicle. A bid was officially opened in 2007 for the construction of the new vehicle designated NFMBR (Nova Família de Blindados Média de Rodas, New Family of Medium Armoured Vehicles on Wheels). In 2009, a partnership with IVECO was settled regarding the first units of the vehicle, now called VBTP-MR Guarani (Viatura Blindada Transporte de Pessoal – Média de Rodas, Armored Personnel Transport Vehicle – Medium on Wheels Guarani), being put into service with the Brazilian Army in 2012.
The VBTP-MR is an amphibious vehicle with 6×6 drive. It is a modular vehicle which can receive extra armor packages and a wide variety of armaments. At the moment, both the APC and Infantry versions are used, but the intention is that it will become the basis of a new family of combat vehicles, including a possible evolution to 8×8 vehicles.
The project aims to deliver 1,580 units of the vehicle and its variations to the Brazilian ground forces by 2040. The Guarani is a modern low-cost armored vehicle, replacing its predecessors.
Development
At the end of the 1990s, due to the Brazilian experience gained in the African peacekeeping missions, the concept of what would be the Guarani began. Initially, an evolution of existing armored vehicles was planned, named NFBR (Nova Família de Blindados de Rodas, New Family of Armored Vehicles on Wheels), nicknamed Urutu III, after a South American venomous pit viper. Several discussions started on what the new family of vehicles was supposed to be for the Brazilian Army. Some documents were issued on the project, with some possible configurations on the 6×6 versions, and a possible 8×8 version suitable for mounting 90 mm and 105 mm guns. A 4×4 light weight vehicle was also considered.
In 1999, the Brazilian Army issued a request for a new family of wheeled vehicles with amphibious capabilities, for the replacement of the EE-9 Cascavel and the EE-11 Urutu, which were built in the 70s by Engesa. The main feature of the new family of armored vehicles would be modularity, being able to receive extra armor packages, several turrets, and a variety of weaponry. Additionally, the new vehicles would also need to be able to be converted into mobile command centers, ambulances and recovery vehicles.
The NFBR
The Brazilian Army opened a bidding in 2005 to receive proposals from contracting companies for the production of the NFBR. The announcement requested a vehicle much more modest than the one discussed in the 1990s, but it was the starting point for its creation. The announcement listed a series of specifications, stressing that the project would belong to the Brazilian Army and not the company producing them. Unfortunately, there was no production planned at the time, as only two companies applied for the contract, with none being multinational, and of the two companies that applied, only Columbus submitted complete documentation. The reason why the Brazilian Army did not accept the proposal from Columbus was because they did not have the production capabilities to produce the NFBR, which made it impossible to proceed and generated great frustration for those involved in the NFBR project.
The reason for the Brazilian Army wanting to own the design of the vehicle is because the rights of the previous projects by Engesa and Bernardini, which were initiated by the Army, were owned by the companies. This caused the development institutes of the Army to have a tiny budget compared to the companies, which meant that the Army was not capable of initiating larger development projects of its own.
The NFMBR
A new formal bidding process was opened by the DCT (Departamento de Ciência e Tecnologia, Department of Science and Technology) in order to receive proposals to produce the now designated NFMBR. The following companies were contacted by the DCT for the contract: Agrale, Avibras, EDAG, FIAT, and IESA. After a period of 80 days, the companies delivered their project documentations, which aimed to develop a prototype and sixteen more pre-production series.
The companies were allowed to associate with other companies, national or international, but at least 60% of the components used for the NFMBR had to be made locally. Iveco’s FIAT Automobiles S / A division won the contract with the possibility of future serial production. Iveco’s first headquarters outside of Europe, named Iveco Defense Brazil, based in Sete Lagoas, MG, was born. In December of the same year (2007), at the Army Headquarters, General Fernando Sérgio Galvão, the Chief of Staff of the Brazilian Army, and the president of Iveco, Marco Mazzu, signed the contract for the production of a prototype vehicle.
In 2007, a conceptual design of the NFMBR was presented at LAAD Defence & Security (Latin America Aero & Defense – Defence & Security, the most important yearly defense expo of Latin America, comparable to Eurosatory in Europe). In total, 10 different variants of the vehicle were proposed:
VBTP (Viatura Blindada de Transporte Pessoal, Personnel Transportation Armored Vehicle)
VBCI (Viatura Blindada de Combate a Infantaria, Infantry Fighting Armored Vehicle)
VBR (Viatura Blindada de Reconhecimento, Reconnaissance Armored Vehicle)
VBC MRT (Viatura Blindada de Combate porta Morteiro, Mortar Carrier Armored Combat Vehicle)
VBE CDT (Viatura Blindada Especial de Central de Diretoria de Tiro, Fire Control Center Special Armored Vehicle)
VBE SOC (Viatura Blindada Especial Socorro, Recovery Special Armored Vehicle)
VBE OFN (Viatura Blindada Especial Oficina, Workshop Special Armored Vehicle)
VBE PC (Viatura Blindada Especial Posto de Comando, Special Armored Vehicle Command Post)
VBE COM (Viatura Blindada Especial Comunicação, Communications Special Armored Vehicle)
VBTE AMB (Viatura Blindada Especial Ambulância, Ambulance Special Armored Vehicle)
The VBTP Guarani
Two years after the contract was signed, at the 2009 LAAD, a full-scale mock-up of the new design proposal for the NFMBR was presented. This vehicle would later be called VBTP-MR, but was designated SAT at the time, discarding the initial design presented in 2007. The mock-up would undergo several changes and the concept of the new vehicle was developed by Brazilian Army engineers who worked together with engineers of Iveco, based on another 8×8 vehicle previously created by the company, the Super AV.
In essence, the VBTP Guarani is a shorter Super AV. The Super AV can be seen as a result of the late version of the Italian Freccia IFV. The Super AV bears some resemblance to the Freccia, the overall layout is comparable, and it was designed by the same company. In essence, the Super AV is a much lighter version of the Freccia. The Freccia is, in turn, a variant of the B1 Centauro.
The assembly of the prototype began in 2009, with the hull being made of German steel delivered by Thyssen-Krupp, and was completed in 2010. Additional armor mounts were added, and a green paint scheme was made in September, followed by the application of the AMAP-L spall liner in October. Subsequently, all the electrical parts of the vehicle, piping, transmission box, suspension, water propulsion engine along with the rear propellers, gearbox, and, finally, its steering system were added. In November, internal benches, periscopes, suspension and steering of the second axle, crankset, radiator, and fan assembly were added, so that, at the end of December, the engine was mounted. At the 2010 Eurosatory exhibition held in Paris, a small-scale model of the 6×6 version of the future Guarani was presented, painted in the Brazilian Army’s color scheme.
The prototype was completed in March 2011 and, in the same month, the assembly of a second vehicle began. This vehicle was to be destroyed during armor tests and only consisted of the hull and wheels. The vehicle was taken to the TWD company, a subsidiary of MBDA missile systems, proving ground in Schrobenhausen, Germany in May, where it was subjected to explosions from 6 kg IEDs. The first was placed on the wheel closest to the driver and the second positioned under the troop compartment suspension wheel. The effects of the explosions were measured with standardized dummies that simulated the proportions of weight on the joints of the human body, that were properly dressed and equipped with helmets and ballistic vests, simulating a combat situation as realistically as possible.
At the end of the tests, it was concluded that the vehicle had a high capacity to guarantee the protection of the onboard troops against threats from mines and improvised explosives.
In the same year, 2011, tests were started with the vehicle to be accepted into service at the CAEx (Centro de Avaliações do Exército, Army Evaluation Center) in Rio de Janeiro. It was later exhibited at the LAAD of 2011 and paraded in the civic parade of September 7th in Brasilia, in celebration of Brazilian Independence Day.
In October 2012, five vehicles were built in Italy and assembled in Brazil. One was a prototype and 4 were pre-production vehicles. The steel of the hulls was produced by Thyssen-Krupp. Three had the UT30BR turret and the other two versions had the REMAX and Allan Platt turrets. It was found that the vehicle with the UT-30BR turret maintained its amphibious capacity, however, it needed additional flotation blocks to maintain stability in adverse conditions. One of these vehicles was presented at the Iveco stand at Eurosatory 2012 and, in October, a concept drawing of the 8×8 version of the VBTP, named VBR-MR 8×8, was released on the Brazilian Army portal.
The contract with Iveco was signed, providing for the delivery of 2,044 units in different versions by the year 2030. Due to the constitutional limit of Army spending in Brazil and the number of modernization projects, the delivery schedule was extended until 2040, with 60 Guarani’s being delivered each year. The first batch was delivered in March 2014 to the mechanized infantry brigade in the state of Paraná. Brazil received another 100 vehicles in September, which ended the delivery of 128 VBTP-MR Guaranis. The vehicles are manufactured in Iveco’s factory located in Sete Lagoas in the state of Minas Gerais. The engines and suspensions are manufactured in Iveco’s plant located in Córdoba, Argentina.
By June 2019, 400 vehicles were delivered, and 500 in November 23rd 2021. These vehicles consist of multiple variants, including some armed with 30 mm automatic turrets (VBCI) and also versions with remote and manual 12.7 mm armed turrets (VBTP). The mortar carrier unit is planned to be built, and the 90 mm and 105 mm versions are being studied for the 6×6 platform and for the future 8×8 chassis, with several companies offering armaments for the Guarani, as seen in the LAADs of the years 2015, 2016, 2017, 2018, and 2019.
Around 2010, the Brazilian company Usiminas and the Brazilian Army started developing a new ballistic steel material to armor the Guarani. This newly developed steel is called USI-PROT-500 and is meant to replace the currently imported steel from Thyssen-Krupp. The goal is to have a 100% nationally produced hull for the Guarani. Development was finished in late 2016 and the newly developed steel passed tests in January 2017. As of this moment (November 2020), the hulls have yet to be produced with the new Brazilian steel, and so far, not a single prototype is known to have been made with USI-PROT-500 steel. Usiminas is heavily advertising USI-PROT-500 together with the Guarani, so it is unclear if production is near. If the steel for the hulls is manufactured in Brazil, it is estimated that 70% of the Guarani is made locally, although an expert in Brazilian vehicles has stated that this number refers more to 70% assembled and not actually produced. The eventual goal of Brazil is to produce 90% of the Guarani nationally to achieve one of its National Defence Policy goals: national sovereignty through national production.
The vehicle’s weight can vary from 14 to 25 tonnes (15.4 to 27.5 US tons), and the turrets are easily removed. This way, the vehicle can be transported by cargo planes operated by the Army, such as the Lockheed C-130 Hercules or Embraer C-390 Millennium.
In February 2020, a modernization plan was announced as a result of the delay of the final deliveries from 2030 to 2040. Unfortunately, the Brazilian Army did not go into detail about the technical specifications of the project. Four months later, in June, another ordinance was published announcing the reproof of the UT30BR turret. As a result of this, the Brazilian Army began its studies looking for a new 30 mm turret to equip the VBCI. The main options of the Army are the UT30Mk2 and TORC30 turrets.
On November 17th 2020, the Federation of Industries of the State of Rio de Janeiro and the Brazilian Army signed a contract for the development of four ‘Driver Procedure Simulators’ for the VBTP Guarani. The simulators have a term of 80 months for construction and development. The simulators will be further supported with ‘Auxiliary Instruction Mediums’ developed by Iveco. The simulator will enable the Brazilian Army to train its crews without using the Guaranis, and thus saving money.
The Army still aims to produce an 8×8 version with a 105 mm cannon, although this will be a new vehicle. As it is still an ongoing project, there is still much to be developed and improved. The VBTP-MR Guarani comes with the proposal to modernize the Brazilian Army and replace the EE-11 Urutu, already very outdated, with more than 45 years of service.
Name
The initials before the vehicle name designate its function according to the Brazilian Army, VBTP-MR (Viatura Blindada de Transporte Pessoal – Médio Sobre Rodas, ‘Armored Car for Personal Transport – Medium on Wheels’) or VBR-MR (Viatura Blindada de Reconhecimento – Médio Sobre Rodas, ‘Armored Car for reconnaissance – Medium on Wheels’). The suffix ‘Guarani’ is a word that derives from the indigenous languages of the Guarani tribe that lived in Brazilian territory before the Portuguese colonization in 1500, which means ‘Guerreiro’ in Portuguese and ‘Warrior’ in English. Besides being an imposing name, it pays tribute to the predecessors that lived on Brazilian lands.
Design
The VBTP is a vehicle that was designed to be adapted to multiple theaters and terrains, such as urban combat, with several versions existing for both low and high-intensity theaters. This was done to standardize the Brazilian mechanized cavalry, serving as a single platform for several different versions that will replace the old Engesa vehicles in all their functions, from troop transport to reconnaissance units.
Since it was designed to be a family of vehicles and, like in the previous Engesa projects, using a larger number of pre-existing automotive components, it is relatively cheap. The Guarani uses mechanical elements from the TRAKKER series, which is a line of civilian trucks produced by Iveco in Brazil.
Hull
The Guarani is 6.91 meters (22.6 feet) long, 2.7 meters (8.8 feet) wide, and 2.34 (7.6 feet) meters tall. The Guarani has a hull composed of German steel supplied by the company Thyssen-Krupp with a V-shaped hull floor. The engine is positioned in the front right of the vehicle. The armor on the lower hull is placed at an angle of approximately 50º. The upper hull plate is at an angle of 15º from the horizontal. It has 4 headlights which are located on both sides of the frontal upper hull plate. The rear-view mirrors are positioned between the headlights. The driver’s hatch has 3 vision blocks in addition to a windshield that can be folded down. The air outlet of the radiator is located right next to the driver’s hatch, and the toolbox (axe and shovel) is located above the engine in front of the radiator outlet. The vehicle has a frontal trim vane. Two small hatches for engine maintenance are located just above the trim vane.
Behind the driver’s hatch, there is the commander’s hatch, which also has 3 vision blocks. A turret ring is located behind the commander’s hatch, which can be enlarged depending on the vehicle’s armament. The gunner is located in a completely protected compartment inside the VBTP, positioned just behind the engine. Finally, two rectangular hatches are located above the troop compartment at the rear of the vehicle. These hatches enable the transported troops to escape, but also lay down fire if needed. On the troop transport version without a weapon system, there are 4 of these hatches.
The vehicle is covered with numerous fixing points which allow the mounting of upgrade packages and flotation blocks, but also for baggage racks. The exhaust is located on the right side of the vehicle, together with the NBC filter cover. At its rear, the Guarani has a ramp for disembarking, and an emergency hatch, and a telephone to contact the onboard crew. The rear headlights are positioned in the center of the vehicle, just below the phone. The Guarani has a rear camera and can install two additional cameras on the sides to give a 360° view. It can mount two Bosch Rexroth A2FM80 propellers for amphibious propulsion and there are two antenna couplings at the top rear of the vehicle. All the hatches of the vehicle are sealed, thus providing chemical and biological defense. The Guarani can weigh up to 25 tonnes (27.5 US tons) when fully equipped.
The Guarani has numerous electronic components for internal monitoring of the crew, a digital panel for the driver, and a 24V CANBUS electrical system. Orlaco Products driver cameras are mounted at the rear, but some can be mounted on the sides as well. The command and control system consists of two Harris Falcon III radios with integrated GPS, a Thales SOTAS intercom, and a Geocontrol CTM1-EB computer.
The troop compartment is located at the rear of the vehicle. Up to 8 fully equipped soldiers can be transported, depending on the variant. Depending on the theater, the benches and floor plate of the troop compartment are heightened and have no contact with the lower hull plate in order to increase crew survivability against IEDs and mines. The troop compartment is cooled with an air-conditioning system.
Crew
The base crew of the vehicle is composed of 3 crew members, the driver, the gunner, and the commander. In its troop transport version, the vehicle can carry 8 fully equipped soldiers, totaling 11 crew members. Future versions of the Guarani, not yet produced, will allow for 3 to 6 crew members, depending on the variant.
Turret
The VBTP Guarani can be seen in multiple versions. The most basic version is the unarmed version. The second version is the VBTP armed with a REMAX RCWS turret (Remote Controlled Weapon System). This is a general-purpose turret, which is mounted on various Guaranis. The machine guns are removed when the Guarani with a REMAX turret is used during humanitarian missions. The third version is the ALLAN PLATT MR-550 turret, meant for low-intensity and peacekeeping missions.
REMAX
Developed through a partnership between ARES and CTEx, the REMAX is a light turret operated remotely by the gunner inside of the vehicle with a joystick. Its standard armament is a 12.7 mm M2HB machine gun and a secondary FN MAG 7.62 mm machine gun. It has four 76 mm smoke grenade launchers, laser rangefinders, night-day and thermal sensors. Multiple Guaranis are armed with this turret.
ALLAN PLATT MR-550
This is an Australian-made manned turret with the operator being protected by an armored dome. It can be equipped with a 12.7 mm M2HB machine gun or a 7.62×51 mm FN MAG, ideal for low-intensity theaters such as Pacific Operations and UN Peacekeeping Missions.
REMAN
In June 2020, ARES offered 2 REMAN turrets to the (AGR) Rio Arsenal of War to be mounted on the Guarani and to be added to the tests. This turret might replace the Australian ALLAN PLATT. It appeared for the first time at the 4th BID Brazil (Base Industrial de Defesa, Industrial Defense Base) in 2016 as a concept version, and its final version was presented at LAAD 2017. The turret offers great possibility to further increase the vehicle’s degree of local production. Just like the ALLAN PLATT, the REMAN is a manually operated turret, having a STANAG 4569 Level 2 ballistic protection and is capable of receiving the same weapons (FN MAG and M2HB). The REMAN turret has undergone testing by the Brazilian Army in mid-September 2021, but no further details have been released as of yet.
Armor and Protection
The Guarani’s hull is made of homogenous High Hardness Steel with a Brinell hardness value of 500. This type of high hardness steel is used for many vehicles of its class. Brazil is planning on constructing the vehicle from nationally developed USI-PROT-500 steel, but so far, it is unknown if this has entered production.
Based on Stanag levels, an estimation of the Guarani’s armor can be made by referencing manufacturers of 500 Brinell armor plates (plates used: Armox 500T, Miilux Protection 500, and Swebor 500). Through cross-referencing multiple types of plates and the needed plate thicknesses to comply with the corresponding Stanag level, a reasonably accurate minimum plate thickness estimate can be made. The recommended thicknesses of the steel plates used for this estimation are identical or nearly identical between the manufacturers. USI-PROT-500 is not used for this estimation as details of STANAG tests are yet to be released by Usiminas.
The base Guarani, without any additional armor, complies with Stanag 4569 level 3 against gunfire from all sides. This means that the Guarani is impervious to 7.62 x 51 mm AP rounds fired from 30 meters (100 feet) at the vehicle. The armor is therefore estimated to be at least 20 to 24 mm thick from all sides. The frontal armor of the base Guarani is said to be impervious to 12.7 x 99 mm AP fired from 100 meters (330 feet), which gives it a Stanag level of 3+, equal to an approximate thickness of between 24 to 35 mm of steel. The Guarani has a Stanag level 2 rating against artillery shrapnel. This means that it is impervious to 155 mm artillery shrapnel from a distance of 80 meters (263 feet).
For both intensive conflicts and asymmetrical warfare, the Guarani can be upgraded with 3 packages. The first of these packages is the AMAP-L spall liner, which reduces the potential spalling cone angle from 87 to 17 degrees. This significantly increases the survivability of the crew in the troop compartment when spalling occurs, which can be caused by projectiles, missiles, penetration by a HEAT-type weapon, mines, or IEDs. It is unclear if this upgrade is standard or optional, as multiple sources are contradictory. A source based on the Army Manual is worded in such a way that it claims the AMAP-L upgrade is standard for the Guaranis.
The second package is the modular composite armor plate system developed by ALLTEC Materiais Compostos. A study of the development of this armor package was released in 2018. The package was developed in multiple stages through simulations and live-fire tests, of which the latter were carried out by CAEx (Centro de Avaliação do Exército, Army Assessment Centre).
The additional armor plate is capable of stopping 12.7×99 mm AP rounds fired from 100 meters (330 feet). This means that the ALLTEC armor package complies with Stanag level 3+, which roughly translates to an equivalent plate thickness of between 24 to 35 mm. The frontal armor with the ALLTEC package is said to be able to stop 25×137 mm APDS-T rounds at 1,000 meters (1094 yards). No estimated thickness can be given. The frontal armor of the upgraded Guarani does not correspond with Stanag level 5, because the armor has to be able to stop a 25 x 137 mm APDS-T round at 500 meters (547 yards). The ALLTEC package raises the Stanag level to 3 against 155 mm shrapnel from 60 meters (197 feet), and gives the vehicle Stanag level 2a protection against 6 kg (13 lbs.) of explosives under any wheel. To further protect the soldiers inside, anti-mine seats are installed and the troop compartment is heightened.
The ALLTEC upgrade package weighs 1.2 tonnes (1.32 US tons) and can be easily mounted on the mounting points which are located all over the vehicle. The armor is mounted with bolts.
Stanag Base Guarani
Location
Protection
Stanag Level 3+
Front
Impervious to 12.7 x99 mm AP fired from 100 meters (330 feet).
Stanag Level 3
All Sides
Impervious to 7.62×51 mm AP rounds fired from 30 meters (100 feet) at the vehicle.
Stanag Level 2
All Sides
Impervious to 155 mm artillery shrapnel from a distance of 80 meters (263 feet).
Stanag Level 2a
Under any wheel
6 kg (13 lbs) of explosives.
Stanag Guarani ALLTEC
Location
Protection
Stanag Level 4+
Front
Impervious to 25×137 mm APDS-T rounds at 1000 meters (1094 yards).
Stanag Level 3+
All Sides
Impervious to 12.7×99 mm AP fired from 100 meters (330 feet).
Stanag Level 3
All Sides
Impervious to 155 mm artillery shrapnel from a distance of 60 meters (197 feet).
Stanag Level 2a
Under any wheel
6 kg (13 lbs) of explosives.
The final upgrade packages that can be mounted on the Guarani are the UFF, or Ultra Flex Fence, and HSF, or Hybrid Slat Fence, manufactured by Plasan. The UFF and HSF are designed to offer protection against RPG-7, SPG-9, and similar types of rocket-propelled grenades. The add-on armor can be attached to all the mounting points of the ALLTEC armor package and both upgrade packages can be used at the same time. Both the ALLTEC and the UFF upgrade packages will be used by the Brazilian Army, especially during UN Peacekeeping missions, but are also offered for export.
Mobility
The vehicle has an Iveco FPt Cursor 9 – 6 cylinder 383 hp (280 kW) diesel bi-fuel engine (it can run on kerosine). This allows the 18.5-tonne vehicle (20.4 US tons) to reach 100 km/h (62 mph) on roads. On rough terrain, an average of 70 km/h (43 mph) can be reached, and an operational range of 600 km (372 miles) on roads. The engine can produce a torque of 1,500 Nm at 1,400 rpm, and 280 kW (383 hp) of power at 1,600 to 2,100 rpm, which gives the vehicle a power to weight ratio of 22 hp/t for its base amphibious version.
The Guarani uses a ZF Friedrichshafen 6HP602S automatic transmission, which has 6 forward gears and 1 reverse. The driving axles are made from aluminum and the tires have a Run-Flat Hutchinson (run-flat tire insert) system, which allows the Guarani to continue driving for 60 kilometers (37 miles) after the tires have been punctured.
The Guarani uses a 6×6 CTIS suspension system. The CTIS, or Central Tire Inflation System, allows the Guarani to control the pressure in the tires. This is done to achieve greater grip and safety in certain situations. If needed, the vehicle can drive in a 6×4 configuration as well. The Guarani has two differentials. The first is located on the front axle and the second on the rear axle. The middle axle is driven by a transfer box differential which makes it a 6×6 vehicle. The individual axles have hydropneumatic dampeners.
The Guarani has a ground clearance of 0.45 meters (1.5 feet), can climb a slope 60%, and can cross a 1.3 meters (4 feet) trench. It can cross obstacles of 0.5 meters (1.6 feet) high, and has a turning radius of 9 meters (30 feet). Without preparations, it has a fording depth of 0.43 meters (1.4 feet).
The vehicle is able to cross rivers at 9 km/h (5.6 mph) when prepared with stabilizers, bilge pumps, and two Bosch Rexroth A2FM80 propellers. The bilge pumps are located in the engine and troop compartments, which are meant to pump out water entering the vehicle. In order to stay stable in the river, it uses a front stabilizing system. Additionally, extra flotation devices can be installed to maintain its capability of firing 30 mm weapon systems while crossing the river.
Variants
One of the main requirements was that the Guarani was supposed to be a family of vehicles. There are various types of vehicles planned for the Guarani platform, from Fire Support vehicles to ambulance vehicles. If all these planned vehicles will actually be designed, built and used, remains to be seen. Currently, Brazil has plans to put 5 variants in service. The VBTP Guarani is the only variant that has more or less finished its development phase. The other 5 variants are still in active development.
Planned Variants for Brazilian Service
VBCI Guarani
The VBCI Guarani (Viatura Blindada de Combate a Infantaria, Wheeled Armored Infantry Fighting Vehicle) is the Infantry Fighting Vehicle variant of the Guarani. The VBCI Guaranis are armed with 30 mm autocannons, which distinguishes them from the VBTP, which are either unarmed or armed with 12.7 and 7.62 mm machine guns. Every VBCI turret that has been considered has been an RCWS one.
The current (2021) VBCI’s are armed with the UT-30BR RCWS turret and it is yet unclear if the Brazilian Army will definitively acquire the UT-30BR turret or the VBCI at all. What is known is that between the 13th and 17th of December, the PqRmnt/5 has been instructed in the maintenance of the UT-30BR. This might suggest that there are still plans to acquire the VBCI Guarani and most likely the UT-30BR.
VBC-MRT
A mortar carrier version is planned, for which several companies have offered their armaments to equip the VBC-MRT. Among them are the following weapon systems: the Ares/Elbit Spear (an evolution of the Cardom 120 mm), Ruag Cobra 120 mm, Thales 2R2M, and the Norinco SM5.
Other Planned Variants
The other 3 planned variants are the VBE PC, VBTE AMB, and the VBC Eng, which are Command Post, Ambulance and Engineering vehicles respectively. These three variants are still in development, and little is known about them except for the engineering vehicle.
VBE PC
Based on other command vehicles in Brazilian service, like the VBE PC M577, it is likely that the VBE PC will receive a tent, which functions as extra workspace for the command team. The Guarani is likely to be supplied with map frames, folding tables, radios, and other command and control equipment. The VBE PC M577 also has an external diesel generator that can supply enough power for all electronic systems of two M577’s when the main engines are not running. It is not improbable for the VBE PC Guarani to also receive an external generator.
VBTE AMB
The VBTE Ambulance, like other Brazilian Ambulance vehicles, will probably receive red cross insignia’s on the front and sides of the vehicle. The VBE AMB M577 in Brazilian service is equipped with transformers that allow power supply to medical equipment, defibrillator, cardioverter, vital data monitors, oxygen and vacuum systems, and a stretcher. The M577 Ambulance is, like the Command Post variant, equipped with an external generator to power its systems. The VBTE AMB Guarani will most likely receive these systems as well.
VBC Eng
The VBE Eng (Viatura Blindada Combate de Engenharia, Combat Engineering Armored Vehicle) is meant as an armored engineering vehicle, like the Pionierpanzer 2 Dachs, which is also in Brazilian Service. These vehicles have a boom or excavator arm installed on the vehicle, and in addition, might be installed with a bulldozer blade. The goal of the Guarani Engineering vehicle is to have an engineering vehicle that can keep up with the other Guaranis in combat.
The Engineering Guarani has two proposed versions: a Guarani with an excavator and a Guarani with a bulldozer. The construction of prototypes has been accepted, but so far, it is unknown if any progress has been made. The system for the Guarani will be delivered by Pearson, which already mounted its system on Piranha vehicles of the Brazilian Marine Corps. The so-called ‘Jettison Fitting Kit’ is a plug-and-play style mounting system that enables easy mounting of the bulldozer and excavator arm without structurally changing the vehicle.
Initial tests were expected to have taken place in the first quarter of 2019 but were eventually carried out in September 2021. An excavator arm, a bulldozer, and loader ladle were tested, but no further noteworthy details have been released regarding the potential or the potential acquisition of the engineering Guarani’s.
Possible Variants
Not much is known about the potential variants of the Guarani. The information on their purpose is based on current vehicles in Brazilian Service, or information revealed by the Brazilian Army. These variants have been seen in multiple sources, but have not yet been realized or have not much more information than their initial release.
VBR-MR Guarani
The VBR-MR is the reconnaissance version of the Guarani. It might be built on either the 6×6 or the 8×8 version depending on the armament that will be selected. The 8×8 version will receive a more powerful engine than the 6×6 Guarani, as the combat weight is estimated to be more than 25 tonnes. Amphibian capabilities with the 8×8 version is a desired requirement by the Army. The most likely 8×8 Guarani candidate is speculated to be the Iveco Super AV. In 2017, the Brazilian Army stated that it did not have the money at the time for the VBR-MR, and the project was subsequently put on hold.
In February 2020, the Brazilian Army released new requirements for a new 8×8 wheeled fire support vehicle. These new requirements call for an 8×8 vehicle, armed with a 105 mm NATO-compatible smoothbore gun. In March 2021, the Brazilian government confirmed that it plans to acquire 221 vehicles until 2026, with shared systems of the Cascavel, Leopard and Guarani. It is confirmed that the 8×8 will be bought from a foreign country and will not be built on either a Guarani or SuperAV hull, but a more or less dedicated vehicle instead.
The vehicles which are currently considered are the Centauro 2, Piranha, AMVxp, ST1, and Tigon. Of these vehicles, only the Centauro 2 fits the requirements of the Brazilian Army, asking for a dedicated FSV. In addition, the Centauro 2 is built by Iveco, which means that in accordance with the Guarani programs, certain components might be produced in Brazil and could share commonality between the two vehicles.
VBE SOC
The VBE SOC (Viatura Blindada Especial Socorro, Recovery Special Armored Vehicle) is the armored recovery version of the Guarani. This vehicle is supposed to tow and potentially carry out basic repairs on other vehicles. Based on the EE-11 Urutu recovery vehicle, it is speculated that the VBE SOC Guarani will receive a crane, winch, and a wide range of tools and spares, to fulfill its role.
VBE Dsmn
The VBE Desminagem (Viatura Blindada Especial de Desminagem, Special Mine-Clearing Armored Vehicle) is supposed to be the mine detecting and clearing variant of the Guarani. Nothing is known about it.
VBE OFN
The exact purpose of this variant is unknown. So far, no Brazilian vehicle of this type is in service. The potential equipment of the VBE OFN (Viatura Blindada Especial Oficina, Workshop Special Armored Vehicle) remains shrouded in mystery. What can be deduced from the name, is that this is potentially a more static mobile workshop compared to the VBE SOC. Where the VBE SOC will carry out small repairs, it might be that the VBE OFN will provide a more sophisticated workshop, with the ability to repair more sophisticated components although this is purely speculative at this time.
VBE COM
Like the VBE OFN, the actual purpose of this vehicle is unknown. The VBE COM (Viatura Blindada Especial Comunicação, Communications Special Armored Vehicle) might provide a more capable vehicle for in battle communications, with more radios and better radio range. The author speculates that this vehicle might be used in combination with the Command Post vehicle, relaying and receiving messages for the Command Post to vehicles and other command posts.
VBE CDT
The purpose of the VBE CDT is, like the previous two variants, unknown. The VBE CDT (Viatura Blindada Especial de Central de Diretoria de Tiro, Fire Control Center Special Armored Vehicle) suggests being a hub for possibly the mortar version of the Guarani, directing fire and receiving data on targets and so on. This is speculation based on the designation of the vehicle.
VBE DQBRN-MSR
The VBE DQBRN-MSR (Viatura Blindada Especial de Defesa Química, Biológica, Radiológica e Nuclear – Média Sobre Rodas, Special Armored Vehicle for Chemical, Biological, Radiological, and Nuclear Defense – Medium on Wheels) is a specialised Guarani, meant for the detection and identification of CBRN agents. The IDQBRN (Instituto de Defesa Química, Biológica, Radiológica e Nuclear, Institute of Chemical, Biological, Radiological and Nuclear Defense) gave a presentation to Army delegations about the available equipment for CBRN detection. As a result, the Rio Arsenal of War has allowed the IDQBRN to conduct on-site visits to research the integration of CBRN detection equipment on the Guarani.
Questionable variants
The following vehicles have been mentioned by a single Brazilian defense journalism source and have been subsequently rehashed by multiple defence websites, like Army Recognition. In contrast with the VBE CDT, VBE COM, and the VBE OFN, of which the purposes are unknown, the following listed variants are not confirmed by any Brazilian Army source. No confirmation on other Brazilian news sites, Brazilian experts, or the Brazilian Army has been found, so the validity of these vehicles should be questioned. These variants should not be seen as real vehicles until more reliable sources start reporting on them.
VBE Lança-Ponte
The VBE Lança-Ponte (Viatura Blindada Especial Lança-Ponte, Special Armored Bridge Laying Vehicle) is supposedly a bridge laying variant of the Guarani.
VBE Antiaérea
Like the name suggests, the VBE Antiaérea (Viatura Blindada de Combate Antiaérea, Special Armored Anti-Air Vehicle) is supposedly the AA version of the Guarani. If the TORC 30 turret is selected for the VBCI Guarani, it could provide AA capabilities.
VBE Escola
The VBE Escola (Viatura Blindada Especial Escola – Média Sobre Rodas; Special Armored Driver Training Vehicle) is supposedly meant to teach the crews how to operate the vehicles. As far as is known, the current crews are trained on the normal VBTP Guaranis, and no specialized vehicle is used for this purpose. The VBE Escola is maybe more of an unofficial term for VBTP’s that are reserved for training purposes, but nothing has been found if VBTP’s are actually reserved for training and carry the VBE Escola designation.
The use of VBTP in the Brazilian Armed Forces
The Guarani is one of Brazil’s most important military projects, replacing the Urutu by offering greater mobility, firepower, and armor. Currently, 6 of the possible variants are planned to be in Brazilian Service. 1580 vehicles are currently ordered. These are the VBTP, VBCI, VBE PC, VBTE AMB, VBC Eng and VBC MRT (APC, IFV, Command Post, Ambulance, Engineering, and Mortar Carrier), of which the VBTP is currently in service and the VBCI is in service but seems to still be in a test phase. It is meant to be capable, efficient, and operable in the wide range of environments in Brazil.
In the northeastern part of the country, it is expected that the Guarani will be most effective in the Caatinga desert. But the Borborema Plateau and mountains to the east of the desert are expected to be more challenging for the Guarani. When in service in the Caatinga desert, it is advised to repaint the vehicles in a desert tone.
In the northern region of Brazil, it is expected to perform very well in the less vegetated areas of the Amazon province. There, it can utilize its amphibious capability, but the forested areas of the Amazon province are challenging for the Guarani. In addition, the HVAC system must always be able to operate, as the high temperatures and humidity are dangerous for the crew inside.
In the mid-western region of Brazil, bordering Bolivia and Paraguay, is the Pantanal region. The Pantanal is the largest flooded grassland region in the world. Although this terrain does bring some challenges, the Guaranis that operate there have not presented any problems, and showed that they were able to respond rapidly for the defense of the Brazilian border.
The largest concentration of Guaranis will be in the so-called Pampas region, which covers the very south of Brazil. Pampa is translated as plain, which means that the Pampas region is a very large and quite flat grassland region, ideal terrain for armored vehicles. This region allows the Guarani to perform very efficiently and allows it to make use of all its planned armaments. It is used as border defense and as deterrence against Uruguay and Argentina, as the Guarani is expected to perform as well in Uruguay and the Pampas part of Argentina.
In the southeast of Brazil, the Guarani is mainly used in law and order operations, like in the favela of Rocinha. It serves as an armored rapid response troop transport and patrol vehicle. In a way, it is tried for urban warfare. Mountainous regions do severely limit the Guarani’s capability.
The Guarani has also been used to support police checkpoints meant to stop drug trafficking and other criminal activities.
Overall, the Guarani’s capabilities seem to be effective for the Brazilian Army in the regions where they plan to use it. Although it faces challenges when operating in mountainous or forested regions, it performs well in the regions where the amphibious capability of the Guarani are used. This amphibious capability, upgraded armor, and wide range of potential armaments are what sets the Guarani apart from the EE-11 Urutu.
Combat Baptism
In February 2018, President Michel Temer approved the federal intervention in the state of Rio de Janeiro, with the aim of alleviating the internal security situation. Thus, the command of the state’s police forces, as well as of the fire department, was passed to General Braga Netto, who two years earlier had commanded the operations to guarantee security in the 2016 Olympics, and gave him autonomy to organize coordinated operations with both police forces and the Brazilian Army.
Several operations were mounted aimed at pacifying the slums of the state. The Army operated several armored units in the pacification of the slums, such as Urutus and Agrale Marrua, in addition to having the assistance of the Marines that operated Mowag Piranha and CLANFs. In the midst of the operations, the VBTP-MR Guarani made its first debut in a low intensity theater, being used in GLO actions (Guarantee of Law and Order), both in the transportation of military personnel to operate inside the slums, and in the escorting convoys of smaller, more vulnerable vehicles, such as Agrale Marruas.
Due to the low intensity of the theater, only the troop transport versions without turrets, and the ALLAN PLATT and REMAX versions were used. The intervention ended in January 2019, with the results being questionable due to the increase of deaths in the state, but with a reduction in robberies and assaults.
Bad Experiences
Due to the distance between the hull of the vehicle and the ground, the Guarani suffers from a possibly chronic problem. Even though it was not used in a large-scale theater, several vehicles have tipped over during operations and exercises. The first recorded accident was on June 8th 2015, when one of the vehicles of the 33rd Battalion of Mechanized Infantry tipped over on a highway. Other incidents were reported, such as at the Cascavel Autodrome, where another vehicle of the 33rd Battalion of Mechanized Infantry tipped over in the middle of the track. As well, a vehicle of the 30th Mechanized Infantry Battalion tipped over on a rural road in Apucarana.
A more serious accident occurred in the city of Condor in the state of Rio Grande do Sul, when one of the vehicles of the 34th Mechanized Infantry Battalion lost control due to a road unevenness and overturned off the road.
Fortunately, none of these accidents caused any serious or fatal injuries, with everyone involved only leaving with light injuries. Although the center of mass of the Guarani is relatively high due to it needing to resist IEDs when compared to the EE-11 Urutu, these incidents can not completely be blamed on as errors of the Guarani. Most of the instances which caused the Guarani to flip were quite extreme in which no vehicle could be expected to not flip over. Usually, the incidents included the Guarani driving at a fairly quick speed when the driver suddenly needed to react when incoming traffic was on a collision course. The Guarani was steered into a ditch or upon a heavily sloped hill which, combined with the speed of the Guarani, would cause the vehicle to flip over. Although an automatic suspension system might help alleviate this issue, it is doubtful if it would have helped in most of the accidents.
Another accident with a UT-30BR Guarani happened on the September 4th 2021. During testing, the engine stopped working, after which water started to enter the vehicle. The bilge pumps meant to pump out the water, most likely only work when the main engine is running and could not pump out the water as a result. No one was injured.
Organization
In their respective brigades, the Guaranis are being used in training for adaptation to the use of the vehicle and familiarization of the troops, as well as in GLO operations (Guarantee of Law and Order). The future versions of the Guarani, with different turrets, will equip most of the mechanized cavalry battalions, and, in this way, retire the EE-9 vehicles that these regiments operate as reconnaissance vehicles. Most units of the standard troop transport version will be for mechanized infantry battalions, as well as the infantry combat version with the new future 30 mm turret, enabling the retirement of the EE-11. The special versions of the armored vehicle will probably be equally divided, leaving the entire mechanized part of the Army standardized on basically a single platform.
In Brazil, an Army division is composed of Brigades, which is a basic unit of tactical organization with a staff of approximately 5000 men. There are two types of Brigades: Infantry and Cavalry, which are composed of the following subunits:
Infantry Brigade
Motorized – Infantry units that are usually carried by trucks and wheeled light vehicles;
Mechanized – Infantry units that are transported by wheeled armored vehicles
Armored – Infantry units that are transported by tracked armored vehicles
Jungle – Infantry units that are specialized in jungle area
Parachutist – Airborne units
Light – Landing units by helicopters
The current use of the VBTP-MR in mechanized cavalry platoons consists of its operation in Combat Groups (GC) operating a REMAX and two AT-4 launchers and units with Support Parts (Pç Ap) equipped with the PLATT turrets.
The current versions of the VBTP-MR Guarani that Brazil operates are used for the transport of troops, being used by the regiments of mechanized infantry.
Most of the Guaranis are under the operation of the Mechanized Cavalry Brigades, where each Brigade has 2 mechanized cavalry regiments. Some units of the Guarani VBTP-MR are operated by the Armored Cavalry Brigades, where there is an armored cavalry squad.
Operators
The main regions that Iveco hopes to sell the Guarani to are South America and Africa. Since the Guarani is relatively cheap, they hope to appease the needs of these continents. These continents are not new to Brazilian equipment, having used and still use Brazilian EE-11 Urutu’s and EE-9 Cascavels.
Lebanon
Lebanon was the first customer for the Guarani, buying 10 Guarani APCs for the Lebanese Army in 2015, which were delivered in 2017. The units sold were separated into two lots, some of which were delivered to the Internal Security Forces of the elite Panthers unit (Al Fouhoud). These received a navy blue color. The others were delivered to the Lebanese Army, which operates the vehicles with the standard sand color of Lebanon. Along with the Guarani, a number of Embraer EMB-314 turboprop attack aircraft have been sold to Lebanon to be used for anti-terrorism and counter-insurgency reasons.
Potential Operators
Argentina
Since 2008, Argentina made plans to incorporate wheeled vehicles in their Army, with the goal of equipping two brigades with wheeled 8×8 vehicles. The vehicles that were required consisted of IFV, APC, and FSV versions. But, like many South American nations, the plans were shelved due to budgetary constraints.
In 2011, interest resurfaced and Army specialists traveled to Europe to see the various wheeled vehicles that were available. There, they came in contact with Iveco and, as such, with the Guarani. The Guarani was evaluated in 2012 and well received by the Argentinian Army. One of the advantages of the Guarani over its competitors was that spare parts could be manufactured at the IVECO factory in Córdoba, Argentina. Although negotiations were made between Iveco and Argentina for the possible acquisition of 14 Guaranis, it did not result in procurement.
In 2015, the Argentinians made an agreement with China to acquire 110 VN-1 8×8 wheeled vehicles, but this was subsequently also frozen because of budgetary reasons. Additionally, concerns regarding the quality of these Chinese vehicles were made by Army officials and specialists and released in October 2020, partially based on bad experiences with the 6×6 WZ-551B1, which was proposed and tested in 2008. Currently (October 2020), three wheeled vehicles are being studied by the Argentinian Army for adoption: the Chinese 8×8 VN-1, the Stryker, and the Guarani. The sale of 27 Stryker ICV’s was previously cleared by the US State Department in July 2020, but did not result in acquisition.
On October 26th 2020, the Argentinian Minister of Defence visited the Iveco factory in Brazil. The Guarani was again presented during a practical demonstration, and, like in 2012, impressed the Argentine officials. The Argentine Minister of Defence added that the engines were already made in the Argentinian Iveco plant. Besides the possible acquisition of the Guarani, the Argentine government is also negotiating with Brazil and Iveco for the possible acquisition of around 1,000 trucks and helicopters produced by Helibrás.
The Guarani was invited by the Argentinian Army to perform trials as one of the finalists of Argentina’s wheeled vehicle project. A test vehicle was requested in April 2021, and from May 25th to June 24th 2021, a Guarani from the 5th RCMec was sent for testing. The tests were performed by both the Brazilians and the Argentinians, with the Argentinians receiving crash courses for the more simple tests to give the Argentinian testers a better idea of the vehicle. The Brazilian soldiers would perform the more difficult tests due to their experience.
The Guarani was first tested for its general mobility capabilities, which included crossing and braking for 5 minutes on a 60% inclined obstacle. The Guarani is said to have passed all the tests of the first testing stage. The Guarani was then tested by performing various day and night exercises and performing an off-road mobility test. The vehicle managed to pass all the tests of the second stage. Finally, the Guarani was tested on sandy terrain and performed shooting trials with the REMAX remote-controlled turret. The shooting tests consisted of day and night shooting and firing on the move. The Guarani was said to have again passed all the tests and the trials in Argentina were an overall success. No orders have yet been made despite the excellent trials in Argentina.
The Guarani would deliver some advantages over its competitors in the form of national spare part production. The Argentinian officials seem to like the vehicle and recognize the advantages, indicated by statements from the Argentine Minister of Defence, but acquisition remains to be seen as budgetary restraints have been haunting the wheeled vehicle project of Argentina for years.
The Philippines
The Philippines have ordered 28 Guarani vehicles through Elbit Systems, as part of a modernization program of the Philippine Army. This deal also includes Sabrah light tanks and 8×8 Pandur fire support vehicles. The original modernization plans called for 114 wheeled APCs, so it is possible that the Philippines will order an additional 86 Guaranis after delivery of the first 28.
According to Brazilian sources, the Guaranis are supposed to be armed with a RCWS armed with a 12.7 mm HMG or a 40 mm automatic grenade launcher. According to Max Defense, the first website to come forth with the orders, the Guaranis are actually to be armed with a 12.7 mm HMG and a 40 mm automatic grenade launcher in a manned turret, which might be replaced with an RCWS 12.7 mm HMG. The Guaranis are to receive Torch-X, Combat NG, and E-LynX systems from Elbit Systems for network connectivity between all the ordered vehicles. These Israeli systems are already in use within the Philippine Army.
The main selling point of the Guarani was that it was cheap, as it is built in Brazil, which has relatively cheaper labor and materials than its Czech-made 6×6 Pandur counterpart. The 8×8 SuperAV was also considered as an 8×8 fire support vehicle, but was not selected as the SuperAV is built in Italy and more expensive.
Ghana
In early July 2021, Elbit Systems announced the signing of a contract with Ghana, for the initial order of 11 Guarani’s. The vehicle is to be armed with a Remote controlled Weapon Station to be provided by ARES, the manufacturer of the REMAX RCWS. It is unknown if the REMAX RCWS will be mounted on the future Ghanese Guarani’s.
Conclusion
After 50 years, it seems that the Brazilian Army has managed to find its successor to the EE-11 Urutu. The Guarani is a modular vehicle, and overall a much more modern one that fits in the current battlefield, and the geopolitical ambitions of Brazil. The Guarani seems to be the new pride of the Brazilian Army, partially because it is nationally produced. But this comes with some problems. Although the Guarani is said to be 60% nationally produced (experts challenge this claim), it was not nationally designed. The Guarani project achieved its goal in bringing the technology to build modern vehicles, but in a way, Brazil is once again dependent on a foreign nation for their armored vehicles.
The biggest threat to the Guarani armored vehicle is Brazil itself though. Military spending has always been an issue for the Brazilian Army and defense industry. It is also one of the many reasons why the Brazilian defense industry collapsed. With the budgetary delays of the Guarani deliveries from 2030 to 2040, it can also be questioned if all the planned variants will be built as well. In addition, upgrade programs to improve the Guarani’s service are already being researched. In combination with the claims of some experts, this might suggest that the Guarani could have issues that need fixing.
Overall, the Guarani is the vehicle that the Brazilian Army wanted and a worthy successor to the successful EE-11 Urutu. It is a modular vehicle, which is, for wheeled vehicles of this weight, well armored, and can be armed and rebuilt in a whole range of vehicles. It seems to perform adequately in the theatres of Brazil where it is used, and there is reasonable foreign interest in the vehicle. If it will become as successful as the Cascavel is doubtful, but it is an important step for Brazil to one day reform a new national defense industry that matches the glory days of Engesa.
Illustrations
Specifications VBTP Guarani
Dimensions (L-W-H)
6.91 meters (22.6 feet), 2.7 meters (8.8 feet), and 2.34 (7.6 feet) meters, 3.33 meters tall with the REMAX maximum(
Total weight, battle-ready
14 to 25 tonnes (15.4 to 27.5 US tons)
Crew
3+8 (Driver, commander, gunner, eight passengers)
Propulsion
Iveco FPt Cursor 9 – 6 cylinder 383 hp
Speed (road)
100 km/h (62 mph)
Armament
REMAX: 12.7 M2 HB and 7.62 MAG machine guns
Allan Platt MR-550: 12.7 M2 HB or 7.62 MAG machine guns
Armor
Capable of receiving shots on the sides of 7.62 mm piercing ammunition and 12.7 mm on the front (It can receive extra armor kit, capable of protecting the vehicle from 12.7 mm fire on the sides, and 25 mm x 137 APDS on the front).
Radio
Falcon III
Range
600 km (372 miles)
Production
500+
Sources
Blindados No Brasil – Expedito Carlos Stephani Bastos
A INDÚSTRIA DE DEFESA NACIONAL COM O EMPREGO DO GUARANI NO EXÉRCITO BRASILEIRO – Academia Militar das Agulhas Negras, Resende-RJ
MT 2355-005-12 – Manual Técnico, DESCRIÇÃO E OPERAÇÃO, Viatura Blindada de Transporte de Pessoal 6X6 – Guarani – Média Sobre Rodas, CHASSI
DEVELOPMENT OF A NEW TECHNOLOGY TO MANUFACTURE AN ADDITIONAL BALLISTIC PROTECTION PANEL (ADD-ON) FOR THE NEW BRAZILIAN ARMORED PERSONNEL CARRIER (GUARANI)
AMAP-L brochure
Vehículos Blindados De America Latina – Resumen De Mercado 2015-2016
Desafios ao Desenvolvimento da Base Industrial de Defesa: A Busca Pela Soberania Nacional
Apresentação VBTP-MSR Guarani
A ÁREA DE ENSINO, PESQUISA, DESENVOLVIMENTO E INOVAÇÃO DO DEPARTAMENTO DE CIÊNCIA E TECNOLOGIA(IME, CTEx, CAEx, DF e AGITEC)
A NOVA ESTRATÉGIA NACIONAL DE DEFESA E O ALINHAMENtO DO PROGRAMA EStRAtÉGICO GUARANI DO EXÉRCItO BRASILEIRO
AÇÃO DE CHOQUE – A FORJA DA TROPA BLINDADA DO BRASIL – N18 2020
A gestão do Programa Estratégico do Exército Guarani dentro uma perspectiva inovadora
United States of Brazil/Federative Republic of Brazil (1944-1972)
Armored Reconnaissance Vehicle – 54 Purchased
With World War 2 in full swing and the United States at war with the Axis, the United States sought to secure its position on the American continent. Through multiple ways, the United States would successfully influence all the American countries to either side with the Allies or stay neutral throughout the conflict. Brazil was one of these American countries which joined the side of the Allies in August 1942, partially because German submarines sank multiple Brazilian ships close to the Brazilian coast and due to Getúlio Vargas’ pragmatic rule of Brazil.
One of the realisations of the United States in their attempt to secure the American continent was that most of the equipment of the armies and infrastructure of the American countries were seriously outdated. Brazil was no exception, as it still operated five Renault FTs and 23 L3/35 in a mixed squadron. During World War 2, Brazil would acquire aid in industry, logistics, army modernisation, and equipment through Lend-Lease. The latter was also done to help deter any neutral American nation from siding with the Axis.
Among the equipment Brazil received were 54 T17 Deerhounds, making Brazil the only country to operate the T17 in regular Army units. In fact, the T17 would be Brazil’s first 6 x 6 wheeled armored fighting vehicle and began the story of 6 x 6 wheeled vehicles in Brazil which still continues to this day with the EE-9 Cascavel and the Guarani APC. Sadly, the Deerhound has become a forgotten vehicle in the United States and it would meet an equal fate in Brazil, being overshadowed by the successful and beloved M8 Greyhound.
The T17 Deerhound
The development of the T17 Deerhound was initiated after Spring 1941, when the British Purchasing Commission submitted their requirements for both medium and heavy armored cars which they wanted to receive as soon as possible. At the same time, the American Armored Force Board came forward with their specifications for a wheeled vehicle based on the British experience in Africa. The medium armored car was designated as T17, and both Ford and Chevorolet came forward with a design.
The Ford design is what is known as the T17 Deerhound today, with a 6 x 6 suspension system. The Chevrolet design was a 4 x 4 driven vehicle that was redesignated as T17E1 and would later be known as the Staghound. Ford’s design initially used two 90 hp Ford engines, but these were replaced with two Hercules JXD 110 HP petrol engines. Both engines used an individual transmission and linked up to a single transfer case. The T17 had, as a result, 8 forward and 2 reverse gears.
The first pilot was delivered in March 1942 but was rejected due to numerous mechanical defects and extensive failures in the axles and transmission. The second prototype would attempt to solve these issues, but would cause the vehicle’s dimensions and weight to become too excessive and it was rejected again. As a result, the contract of the T17 Deerhound was reduced to 250 vehicles. Originally meant for the British, which had named it T17 Deerhound, they rejected it as well. As a result, the 196 T17 Deerhounds were delivered to the Military Police units in the US with their guns removed, while, unknown to many, 54 T17s were delivered to Brazil through Lend-Lease.
The T17 in Brazil
The story of how Brazil ended up being the only country to receive and operate the T17 Deerhound in combat units is an interesting one. It seems odd that Brazil would order a rejected platform of vehicles, regardless of any lack of materiel or perceived urgency of acquisition. It seems even more odd as the M8 Greyhound was already in service and in use. The answer to this question is that Brazil did not order the T17 Deerhound to begin with. Brazil had ordered 54 M8 Greyhounds, which supposedly arrived in Brazil with the order number of the M8 and the needed documentation. But when the Brazilians started unloading the shipment, it turned out that the ordered M8’s were T17 Deerhounds instead. This was not the only instance either, as a Brazilian archive document requesting clarification from the United States about this issue, also talked about 105 mm M3 howitzers being replaced with 75 mm M1A1’s instead.
Considering the context of the T17 Deerhound project and it being rejected, it seems to suggest that the United States deemed the allocation of M8 Greyhounds to Europe of a higher priority than supplying them to Brazil. The T17 Deerhound was then the perfect vehicle to send instead, as it was still a 6 x 6, they had 250 rejected vehicles standing around, and it was a fairly similar but overall bad vehicle compared to the M8 Greyhound. It thus seems that the United States intentionally dumped the T17 Deerhounds in Brazil.
Brazilian sources are unclear as to when Brazil received the T17 Deerhounds, as they estimate the delivery of the T17 from 1943 to 1944. What is known is that 18 T17 Deerhounds were put into service in September 1944. It would receive the local classification of Carro Blindado de Reconhecimento or CBR (English: Armored Reconnaissance vehicle). The Deerhounds would serve as both reconnaissance and command vehicles.
The T17 was delivered to 3 units, 2 were Regimento Motomecanizado’s (RMM) (English: Motomechanized Regiments) and the other was a Batalhão de Polícia do Exército (BPE) (English: Police Battalion of the Brazilian Army). The Regimento Motomecanizado’s would later be renamed and reorganized on May 17th 1946 as Regimento de Cavalaria Mecanizado (RCMec) (English: Mechanized Cavalry Regiment).
Markings would also start to be standardized around this time. From pre-1946, when they used a star in the colors of Brazil, it was replaced from 1946 to 1983 with the Cruzeiro de Sul, translated as Southern Cross. In addition, the registration of the vehicles was also standardized, with the EB10-XXX format. EB referred to Exército Brasileiro, the 10 to the type of vehicle, in this case, a reconnaissance vehicle, and the XXX (for example, 084) to which vehicle.
From November 1953, the units would be redesignated as Regimento de Reconhecimento Mecanizado (RRecMec) (English: Mechanized Reconnaissance Regiment) until about 1968-1969, after which they would be designated as RCMec again, which they maintain to this day. Since sourcing mostly refers to the RRecMec and this was the longest period in which the T17 served under this regiment designation, the RRecMec designation will be used for future chapters.
2º RRecMec
One of the regiments to receive 18 Deerhounds was the 2º RMM, stationed in the Rio Grande do Sul state, at Porto Alegre. There, they would be operated along with M3A1 Stuarts, but also with M3A1 Scout Cars and Willys Jeeps. Practically, nothing is known about the T17s which served in the 2º RRecMec, except for a single one. EB 10-084, nicknamed ‘Tuiuti’, was retired in 1970, and turned into a monument in Jaguarão in Rio Grande do Sul state. If this particular T17 still exists is unknown. This is because none of the known surviving T17s have the same registration numbers or markings. There are three Deerhounds without any markings at all, so there might be a slim chance that one of these is the ‘Tuiuti’.
3º RRecMec
The 3º RRecMec is, relatively speaking, a more documented regiment regarding the T17. 18 T17 Deerhounds were delivered to the then 3º Regimento Motomecanizado’s on September 4th 1944, stationed in Bagé in Rio Grande so Sul. There, they equipped the 3rd and 4th Esquadrão de Carros Leve (English: Light Vehicle Squadron) and served alongside 34 M3A1 Stuarts which were delivered around the same time.
With the switch to the RCMEC, the Deerhound would serve under a new composition of two reconnaissance squadrons consisting of T17s, M3A1 Scout Cars, and Willys Jeeps, a Light Tank Squadron of M3A1 Stuarts, a command squadron, and a service squadron. The 18 T17s would receive the registrations from EB10-126 to 136, and from 138 to 141. A single Deerhound, thought to be used as a command Deerhound, was designated EB10-123. Interestingly, this Deerhound is thought to have been one of the final T17s in service, as it was retired in 1972.
1º BPE
Like with the 2º RRecMec, practically nothing is known about the service of the T17 within the BPE, which was located in Rio de Janeiro. The only thing that is known is that at least 3 T17s were delivered to the Military Police. If the BPE received 18 Deerhounds is unknown. What is known is that they used them in parades and that they were supposedly retired around the 1970s. The BPE might have been the last operator of the T17 Deerhound.
The Brazilian response to the T17?
Although the T17 was certainly an upgrade compared to the Renault FT or the FIAT-Ansaldo L-3, the Deerhound was not popular among the crews. The two Hercules JXD engines had to be synchronized, which was supposedly quite challenging. Because of this, the Deerhounds were usually not really usable. To make matters worse, driving the vehicle on a single-engine in order to get around the synchronization issue would damage the drive shafts. All in all, it seems that the errors which the first T17 prototype had were not really resolved or were simply unfixable because of the T17’s fundamental conception of two engines.
Fate
The exact fate of the T17 Deerhounds is unknown. At least 4 vehicles have survived, while the fate of the rest is uncertain. According to Brazilian sources, some of the 37 mm guns were used to arm the 37 mm VBB-1 project. But this is not necessarily presented as a fact. It would not be surprising if the Brazilian engineers used these guns, considering it would have been cheaper to repurpose the guns, and the T17 was practically retired when these projects started in 1970. It is thought that the other 50 T17s have either been scrapped or used as range targets.
The remaining Deerhounds
As far as known, only four T17 Deerhounds still exist in the world. All of these Deerhounds are in possession of Brazil, being retired vehicles from the previous three regiments. The T17s are in mixed condition, with a single vehicle being the most complete, still having both engines, but missing a turret basket. One of the four vehicles is currently being restored by the Centro de Instrução de Blindados (CIBld) (English: Armored Personnel Training Centre).
The most complete T17 is located at the Museu Militar do Comando Militar Sul in Porto Alegre Rio Grande do Sul. This T17 has the registration EB10-170. Considering the 2º RRecMec was located in Porto Alegre, and the EB10-170 is not one of the 3º RRecMec designations, it is quite likely that this Deerhound came from the 2º RRecMec. What is interesting is that the EB10-170 registration is not on all pictures of this T17, suggesting that it might have been painted on at a later date and that the registration might not have been its original registration, or of any other T17 Deerhound at all.
Another T17 was functioning as gate guardian at the 4º Batalahão de Logistica (English: 4th Logistics battalion) at Santa Maria, Rio Grande do Sul. This gate guardian has since been renovated by the CIBld, and is now presented at the Museu de Blindados do Centro de Instrução de Blindados in Santa Maria, Rio Grande do Sul. It has no registration. The hatches of this vehicle are supposedly welded shut, and as such, this vehicle has probably just received an exterior overhaul and is not in running condition.
The third T17 is located at the 1º Parque Regional Manutenção in Rio de Janeiro. Not much is known except that, between 2005 and now, it seems that either the 37 mm gun has been removed or cut off. Considering that this Deerhound is located in Rio de Janeiro, it is quite likely that this vehicle originated from the BPE.
The fourth Deerhound is located at the Parque Histórico Marechal Manuel Luís Osório in Tramandaí, Rio Grande do Sul. This vehicle also does not have any registration, but considering it is located close to Porto Alegre, it is quite likely that this Deerhound came from the 2º RRecMec.
Conclusion
The Brazilians needed to modernize their Army and the US needed to supply the Brazilian Army with new equipment to strengthen their resolve on the Allied side. The T17 Deerhound seems to have been more of an equipment dump by the US, than military-aid. It is possible that the Brazilian Army may have ordered the T17 themselves, but either way, it was not much of an improvement. The T17 was not loved by its crews, and the mistakes which had made the US reject it were not fixed or were unfixable.
This was Brazil’s first 6 x 6 and it had made Brazil practically the only country in the world to have operated the T17 in regular Army units. Sadly, the T17 Deerhound ended up with an almost equally tragic story within the Brazilian Army, as it had with the US Army. A rejected vehicle, plagued with significant issues, and most of all, overshadowed by the successful M8 Greyhound.
Illustrations
Specifications (T17 Deerhound)
Dimensions (L-W-H)
5.5 meters x 2.6 meters x 2.3 meters (16.4 feet x 7.5 feet x 7.5 feet)
Total weight, combat loaded
14.5 tonnes (16 US tons)
Crew
5 (Driver, Co-driver, Commander, Gunner, Loader)
Propulsion
Two Hercules JXD 6-cylinder in-line 110 hp gasoline engine
Front upper 19 mm (0.75 inch)
Front middle 19 mm (0.75 inch)
Front lower 19 mm (0.75 inch)
Side 19 mm (0.75 inch)
Rear 12.7 mm (0.5 inch)
Top 16 to 9.5 mm (0.625-0.375 inch)
Floor 6,5 mm (0.25 inch)
Turret
Front 32 mm (1.25 inch)
Gun mantlet 25 mm (1 inch)
Sides 32 mm (1.25 inch)
Rear 32 mm (1.25 inch)
Top 19 mm (0.75 inch)
Acquired
54
Sources
Ford M-8 Greyhound Exército Brasileiro – Surge o conceito de blindado 6×6 – Expedito Carlos Stephani Bastos
Fiat-Ansaldo CV-3 35 II no Exército Brasileiro – Expedito Carlos Stephani Bastos
Extermine o Inimigo – Dennison De Oliviera
Deerhound – Paulo Roberto Bastos and Hélio Higuchi Armored Car: A history of American Wheeled Combat Vehicles – R.P. Hunnicutt
In Hiromu Arakawa’s Fullmetal Alchemist, the fictional country of Amestris, based on early 20th-century European countries, with Prussia and the German Empire being the most noticeable influences, is beset by enemies from almost all sides. Amestris is in constant and intentional war with neighbouring countries. To be able to fight these wars, Amestris is developing new technologies and war machines. One of these war machines is the tank.
As the Fullmetal Alchemist story has been adapted in three different series, these tanks and their origins differ as well. In the Manga and the Fullmetal Alchemist: Brotherhood Anime, the tanks were developed to help defend the country against its northern rival, where every technological edge is of vital importance to Amestris. These tanks are still prototypes and produced in very small numbers, but their first combat experience has shown promising results. The design of the tanks of these two adaptations are quite different: where the Manga tank resembles a fusion of the British WWI Tank Mark 1 and the Ferdinand, the Fullmetal Alchemist: Brotherhood tank resembles a fusion of a Panzer IV, Tiger 1, and VK 30.01 (H).
The third adaptation is from the Fullmetal Alchemist Anime. The origin of this tank is unknown, but it is likely to be a technological culmination resulting from decades of war. These tanks seem to be more common than the tanks of the previously mentioned adaptations, as it is suggested in the Anime that Amestris has experience in tank warfare. The tank from this Anime adaptation resembles a Renault FT tank.
The Amestrian need for tanks is clear, and their first steps in designing tanks seem to be very promising, albeit unrealistic in technology, the time frame of the setting, experience, and potential specifications. By using real tanks, the illustrators managed to come up with some viable tank designs for Amestris.
Fullmetal Alchemist
Fullmetal Alchemist is a manga series written and illustrated by Mangaka Hiromu Arakawa (the male pseudonym of Hiromi Arakawa), of which two animated adaptations were made by studio Bones. The story of Fullmetal Alchemist, abbreviated to FMA, takes place in the fictional country of Amestris. Amestris is in a state of constant and total war with almost all of its neighbouring countries. In the north, the mighty Drachma (similar to Russia) always threatens Amestris, waiting for its opportunity to break its shaky non-aggression pact with Amestris by besieging the fortress of Briggs and invading. In the east, the Amestrians are embroiled in centuries-long and multiple very bloody border conflicts with Creta, a highly diverse federation consisting of various tribes which were unified by the leader of the most influential tribe around the year 900. The Principality of Aerugo (similar to Italy) lies on the south side of Amestris. Aerugo and Amestris are, like Amestris and Creta, entrenched in a bloody border conflict after Amestris invaded Aerugo by taking the town of Fotset and some territory as well. A desert on the east side of Amestris splits Amestris apart from Xing (similar to China, with some Japanese inspirations as well), with the countries having had no conflicts.
The reason why Amestris can fight these three countries and still remain in a status quo (the status quo is intentional from the Amestrian side) is because of the highly militaristic and authoritarian regime of Amestris. The State Military of Amestris effectively controls the entire state of Amestris under the command of Führer King Bradley (Generalissimo King Bradley if translated directly from Japanese).
The series mostly takes place between 1911 and 1915 and the technology available to Amestris is comparable to that of the European powers during World War 1, albeit with some stark differences. Weapons shown in the series seem to be based on real-world weapons, such as the Mauser C96, Mosin-Nagant rifle and the 7.5 cm Pak 40. Another comparison that can be made is the development of the first tank in the region and possibly the entire FMA world at that time. An important difference between the technology of our world in between 1911 and 1915 compared to that of FMA is that Amestris does not seem to have any airfaring capabilities at its disposal. Another difference is the widespread use of so-called automails, short for automotive armored prostheses. These highly advanced prostheses are linked to the nervous system and function almost identically as a human limb.
In this universe, Alchemy is one of the most important sciences of the country. Alchemy uses transmutation circles with which an alchemist can create an object or change the structure of an object by presenting a material of equal value according to the Law of Equivalent Exchange. Skilled Alchemists can undergo an examination to become State Alchemists. When an Alchemist becomes a State Alchemist, he or she is employed by the Amestrian State Military and can be called upon to fight as human weapons in times of war. A State Alchemist is also employed to do research in Alchemy for the Amestrian Army for various purposes or perform other tasks involving state matters.
Amestris is a parliamentary republic, although the parliament is a facade of a stratocracy which rules Amestris. It is led by Führer King Bradley together with an advisory staff consisting of the highest-ranking officials in the country. The government is almost completely centralized by the military and the military is present in all forms of public life. From regional governors to mine owners and from scientists to detectives, the State Military of Amestris holds a relatively strong grip on its country and inhabitants, except for some more or less intended conflicts and civil wars.
Amestris put down a very bloody revolt between 1901 and 1908 in the province of Ishval, in the Eastern sector of the country. The revolt eventually spread across the Eastern sector, but was violently crushed in 1908 when the State Military called upon the State Alchemists. The Ishvallan people were massacred and the area was devastated. Border conflicts with Aerugo and Creta intensified after the Ishval Civil War. In 1914, the State military crushed a religious revolt in Liore and defeated a large Drachman Army, which attempted to breach the Northern Fortress of Briggs. It is important to note that these conflicts were all intentionally caused by forces within the upper echelons of the Amestrian State Military in order to provide enough bloodshed for their masterplan. All these years of warfare eventually led to the first tank of the Amestrian Army.
Designation of the Tanks
There are three different takes on the tank in the FMA universe. These can be divided into FMA manga, FMA Anime (2003), and FMA: Brotherhood Anime (2009). The FMA: Brotherhood anime adaptation follows the story of the manga as faithfully as possible, while the FMA anime adaptation follows the first seven volumes of the manga, but on the request of Hiromu Arakawa, the 2003 adaptation would have its own original ending.
As such, the FMA manga and the FMA: Brotherhood vehicles are, by place of origin, the same. The Tank never got an official designation in either the manga or its Brotherhood anime adaptation. For this reason, the tank will be designated after the location it was designed and built, and receive the designation Briggs Tank. Additionally, this designation is the most widely known and accepted designation for the vehicle other than Tank by the FMA community.
The designation and development location of the tank from the 2003 FMA anime are both unknown. In the Fullmetal Alchemist Collectible Card Game, in the Seven Deadly Sins set, the tank is designated as Battle Tank. This also seems to be the designation used by some members in the FMA community, although it is good to mention that the Battle Tank from the 2003 anime is more obscure than its Briggs Tank counterpart.
Briggs Tank FMA Manga
The first appearance of tanks in the FMA Manga is in Chapter 65, which shows the construction facility, including a few tanks under construction. The first encounter and usage of the Briggs tank is in Chapter 66.
Development
The development of the Briggs tank started at an unknown date at the research and development level of Fort Briggs. Fort Briggs is a military base situated at the Northern border, between Amestris and Drachma. The base is a massive wall that closes off the supposedly only passageway through the mountains. Major General Olivier Mira Armstrong, the commander of Fort Briggs, wanted as many techniques in her arsenal as possible to combat Drachma, possibly the only bordering country which can rival the military power of Amestris. As such, Major General Armstrong has a great interest in the development of the tank.
Additionally, because Fort Briggs is located in the most northern part of Amestris, the researchers and engineers are probably some of the most knowledgeable experts in Amestris, likely second to only the State Alchemists, when it comes to mechanics of materials. In order to keep automails running and to prevent their users from dying from frostbite, the materials used for the automails had to comply with various specifications. Through trial and error, the engineers at Briggs have managed to create a material consisting of duralumin, carbon fiber, and nickel-copper alloys. It can be expected that the engineers at Briggs have developed various materials which could be used for tanks in their effort to find usable materials for automails. It can also be expected that the specifications of the Briggs tanks demand for a vehicle which can be used in extremely cold and snowy mountain environments. The soldiers of Fort Briggs use special oil for their automails and they also have a special composite fuel at their disposal.
The Briggs Tank in Detail
The actual specifications of the Briggs Tank are unknown. The following specifications are based on estimations, speculations, and assumptions. By comparing the Briggs Tanks’ dimensions to those of characters, the Briggs Tank is about 5 meters (16.4 Feet) long, 4 meters (13.1 feet) wide, and 2 meters (6.6 feet) tall. The tank is operated by 4 or 5 crew members, consisting of the Commander (left turret rear), Gunner (in front of the commander in the turret), Loader (right of the gunner in the turret), Driver (left front hull) and Co-driver/Hull Machinegunner (right front hull). The Briggs tank has been operated without a commander in one instance, where the gunner acted as the commander, but this was most likely a single occurrence. The tank has a rear turret configuration.
Hull
The hull of the Briggs Tank seems to be inspired from the British World War 1 Mark I to Mark IV tanks. Interestingly, the rear part of the suspension is shaped differently from the Mark I. The Briggs tank’s suspension has a trapezoidal shape as seen from the side, as opposed to the iconic rhomboid shape of World War I British heavy tanks. The sides of the hull, which cover the suspension, are riveted in a very similar way to the Mark I tanks. Additionally, the driver’s sight and hull machine gun port are also riveted to the hull. The upper hull is loosely based on the Ferdinand’s upper hull.
How the armor plates of the front hull are connected to each other is unclear, as there is no sign of welding or riveting. Rivets can be seen on the top hull plate parallel to the upper front hull plate and the side hull plates. Most likely, the frontal hull plates are welded together. The upper front plate would then be riveted to the top plate of the hull. Drawings from the inside of the front hull support this theory, as the top hull plate seems to rest on an additional bend in the upper front hull armor, but no rivets are shown to connect this supposed connection plate to the upper hull. The side armor is likely to be riveted in the same way as the front hull. A single drawing shows that the rear armor plate might also be a single plate that was welded or riveted to form an upper and flat rear armor plate. The flat rear plate shows a hatch, but it is unknown where the hatch leads.
The bottom of the flat rear armor plate seems to be riveted to a connecting profile, which connects the rear hull plate to the floor hull plate. Since there is no similar type of connection profile between the lower front plate and the floor hull plate, it can be suggested that the floor plate is welded to the front plate.
The armor angling and armor values of the Briggs tank are unknown but based on drawing, the armor does not seem to be exceptionally thick, but not very thin either. Based on the usage of the tank during Colonel Roy Mustangs’ coup d’etat and the subsequent defense of the captured Central Command, it can be expected that the tank is at least impervious to small arms fire from the front.
The Briggs tank has a bow-mounted machine gun operated by the co-driver. The way the machine gun is mounted might severely limit the angles at which it can fire. Additionally, the co-driver seems to have no means of vision of his own. The driver has access to a direct sight vision port. The vision port is made of glass which can be covered by a metal plate. If this plate can be opened or closed from the inside, is not clear. The Tank has a towing hook on the front and provides space for pioneering tools on the fenders. On the left fender, the Briggs tank has a box. If this box is meant for storage or served another purpose is unclear. Interestingly, the Briggs tank has some sort of exhausts on the front top plate of the hull, but no engine is shown and it is not positioned in between the driver’s compartment and the turret, as the drawings show both the driver and the turret basket behind him.
Two doors have been placed on both sides of the hull. The purpose of these doors is unclear. Since the location of the engine is unclear, the doors could function as access points to the engine. The doors could also be used as entrances and escape hatches for the driver and co-driver, as they do not have any other hatches near their seats. The doors could also serve as a way to reach and close off side sponsons which could be mounted on the side of the tank, like the Mark I tanks (although this is quite unlikely and far-fetched, it is still good to mention the possibility). The side sponson system on the Briggs tank would then bear some similarity in function with the TOG 2. The doors could be remnants of an early stage of the Briggs Tank which might not have had a turret and used side sponsons instead. The turret might later have been added and the side sponsons removed. The engineers would then probably have closed the holes in the armor with these doors, as to not have to build entirely new hulls, but still keep the option for mounting side sponsons.
The driver uses two traditional tiller bars to steer the vehicle and most likely a gear stick on the driver’s right side. The driver is shown to have two pedals, which can be assumed to either be an accelerator and brake pedal combination, or brake and clutch pedal combination. The latter would be the most logical. This suggests that the speed of the tank is controlled by the tiller bars. The clutch is released with one of the pedals, the tank is halted with the other pedal, and the possible gear stick on the right side of the driver for shifting gears.
Mobility
The engine of the Briggs Tank is unknown and its location within the vehicle is also unknown. The problem with the Briggs Tank is that its layout and interior do not line up with a realistic engine placement. A rear-turreted vehicle normally has the engine either at the front of the vehicle, possibly at either the right or left front of the vehicle, or between the driver’s compartment and the turret fighting compartment. The Briggs Tank has neither of these possibilities. The Briggs Tank has both a driver and a co-driver/machine-gunner. This configuration makes the front engine placement impossible. Additionally, drawings showing the inside of the vehicle depict a compartment where nothing is in between the driver and the turret.
A possibility is that the engine is located under the turret. The turret has a turret basket which is suspended into the hull up to the heads of the driver. This means that there is about 0.8 m (2.6 feet) of height left for an engine. This is quite small, as a Ford GAA engine, used in the M4 Sherman, is about 1.5 meters (4.9 feet) tall. A boxer or flat engine could be used instead to solve this problem. The location of the door on the rear would support a possible engine in the rear of the vehicle, as it could be used for maintenance of the engine. The doors on the sides of the vehicle could provide an easy way to maintain the engine as well.
The Briggs Tank uses a running gear similar to that of the Mark I tank. The Mark 1 running gear had a drive sprocket in the lower rear and an idler wheel at the upper front. The lower rear drive sprocket on the Mark 1 was a complicated drive system. The driveshaft had a sprocket which drove a larger sprocket with a chain, which was connected to the central pivoting axle. The larger sprocket would turn the central pivoting axle, which would drive another sprocket connected to the central pivoting axle, inside the rhomboid-shaped suspension. This sprocket would, in turn, drive a lantern pinion through a chain, and the lantern pinion drove the drive sprocket of the tracks. The advantage of this complicated chain system is that the chains would not transfer external shocks to the differential components.
The top part has no wheels whatsoever and the lower part consists of unsprung rollers. The Briggs Tank has an estimated 16 rollers on each side of the vehicle. This is quite a bit less compared to the Mark I, which had 26 rollers on each side. This can be explained through the shape of the suspensions. The Mark I has a rhomboid-shaped suspension, while the Briggs Tanks’ suspension is shaped like a trapezium. This effectively means that the Briggs Tank misses 8 rollers. If a Mark I tank would have a similar shape as the Briggs Tank, it would have had 18 rollers. Like the Mark I, the Briggs Tank has a track tension adjuster at the front of the suspension, located at the idler wheel.
The Briggs Tank has proven itself to be able to drive up quite a steep slope, but the angle of the slope is unknown. It is estimated between 30 and 45 degrees although it varies per drawing. Based on the preferred design angle of stairs in the real world, the slope is estimated between 30 and 37 degrees.
Turret
The turret of the Briggs Tank is very heavily inspired by the casemate of the Ferdinand tank destroyer. Although the front and the upper parts of the turret armor are either rounded or angled, the hatches and their locations are identical. Also identical is the gunner’s periscopic sight and its semicircular slot in the top of the turret. On the Ferdinand, this allowed the sight to follow the gun as it traversed in the superstructure. It is useless on the turreted Briggs tank.
The gunner is located on the front left of the turret and has access to his own hatch. The gunners’ hatch is the same as on the Ferdinand, a sliding hatch for the aiming telescope, combined with an escape hatch. The loader is located on the front right of the turret and has his own escape hatch. The commander is located on the bottom left, as demonstrated by Major General Olivier Mira Armstrong. Interestingly, these positions are swapped when compared to the Ferdinand. On the Ferdinand, the commander is located on the front right, while the gunner is located on the left rear. The two small hatches on both sides of the rear turret are periscopes for the loader. It could be argued that these would still be loader periscopes on the Briggs Tank, but during its usage, the left rear position is clearly used by the tank commander.
The rear hatch is both an escape hatch and used to eject shell cases. It consists of a large hatch and a smaller hatch in the middle. The middle hatch is used to eject shell cases during, for example, combat conditions. As the turret is based on the Ferdinand, it can be suggested that the ammunition of the vehicle is stored in the back and the middle of the turret.
Armament
The armament of the Briggs Tank is unknown. In the drawings, the armament seems to be of a very high calibre. Two types of armaments can be suggested based on the equipment of the Amestrian State Military and the inspiration of the Briggs Tank. The first armament is the artillery gun used to defend Fort Briggs. It seems to have a caliber that could be high enough for the Briggs Tank. Additionally, the gun is used in Fort Briggs, and thus is a proven and familiar weapon to the engineers of Fort Briggs.
The only reason why this gun could be used in the Briggs Tank is because of the similarity in the turret design between the Ferdinand and the Briggs Tank.
The first possibility is most likely the gun which was used on the Briggs Tank, although, most likely, converted into a tank gun. The gun of the Briggs Tank is a rifled gun and an estimated 3 to 4 meters (9.8 to 13.1 feet) long from the outside of the turret, the barrel length would be larger in total, as a decent part of the barrel would be located in the turret itself. Based on the drawing of the artillery piece stationed on the Briggs wall, the total barrel length is estimated to be in between 5 to 6 meters (16.4 to 19.7 feet), of which 1 to 2 meters would be located in the turret. The diameter of the gun is very hard to give a reasonable estimation to, as the size differs in every drawing and as such, no reliable estimation can be made.
The Briggs Tank has two to three different types of ammunition at its disposal. It has a solid shot armor-piercing round, which was used during its first test drive. When the ammunition was fired, the projectile did not detonate on impact, meaning it was not an armor-piercing high explosive round. The rounds used during the first test drive could also have been training rounds, but with the situation surrounding the first test run, this seems highly unlikely. The second or third round is a high explosive round, which was used during Colonel Mustangs’ coup d’etat of central command. The projectile was fired at the wall of central command.
In addition to the main gun, the tank uses a machine gun as secondary armament, located at the hull’s front.
Service
The Briggs Tank was first used and tested during the winter of 1914 when the homunculus named Sloth accidentally breached Fort Briggs from the underground. The soldiers had never encountered a homunculus before and had no idea what a homunculus even was. Sloth is sometimes referred to as the unknown intruder. The homunculus was thought to be a spy from the neighbouring country of Drachma.
Homunculi are artificial humans made with the help of philosopher stones, in essence they can not be classified as humans, as their life is bound to their philosopher stone. When a homunculus ‘dies’ enough times, the energy of the stone will be depleted and the homunculus will die indefinitely. Because the homunculi’s life is bound to their philosopher’s stone, they are essentially superhumans which can have special abilities like shape-shifting or superhuman strength. In addition, the stone will regenerate damaged body parts of the homunculus until the stone is depleted of energy. Sloth was a massive homunculus, with near-impenetrable skin, extreme strength and could be extremely fast.
When Sloth breached Fort Briggs, he was almost immediately shot by soldiers of Fort Briggs. The soldiers quickly discovered that their weapons could not penetrate the skin of the homunculus. The alarm was raised and the military base was put on high alert. The Homunculus accidentally activated an elevator which brought him to the production floor of the Briggs Tank. Upon his arrival, the homunculus was shot by Major General Olivier Mira Armstrong with a large caliber recoilless rifle, but this had no effect. Major General Armstrong took command and the defenders of Briggs decided to use their newly built tanks to defeat the homunculus as fast as possible, in an attempt to not alert the army of Drachma of their situation.
The Major General assumed command of one of the three available tanks. These vehicles were not yet tested and the encounter with the homunculus was their first test run. The guns were loaded and promptly fired at the homunculus. They managed to hit the homunculus and wound him, but the homunculus simply healed his wound with the help of his philosopher stone. In response, the Briggs defenders continuously fired rounds at the homunculus to no avail. Thinking quickly, the Major General decided that they could not defeat the creature with firepower and decided to defeat the homunculus by freezing him. She used her tank to ram the homunculus into an elevator. One tank was not enough and she ordered the other two Briggs Tanks to help push the homunculus in the elevator. Once in the elevator, the homunculus was sent to one of the openings in the wall. Major General Armstrongs’ tank soon entered the elevator as well and upon arriving at the same floor, they shot the homunculus with the main gun over the edge of the wall. The homunculus, doused with fuel, froze almost immediately in a blizzard.
The first test run can be hailed as a success. Even though the Briggs Tank was not able to reliably penetrate the thick skin of the homunculus, the tank did not break down and managed to perform its mission by defeating the unknown intruder.
The second usage is during Colonel Mustang’s coup d’etat during the spring of 1915 in Central City, the capital of Amestris. The soldiers of Briggs and the soldiers of the Eastern sector of Amestris supported Colonel Roy Mustang in his endeavor to take control of the country and overthrow Führer King Bradley. The armies of the Northern and Eastern Sector were conducting joint exercises on the day of the coup, overseen by King Bradley himself. King Bradley was convinced by his general staff to return to Central, due to suspicions of a potential coup by the Eastern sector led by their commander, General Grumman. The train carriage that took King Bradley to Central was bombed by soldiers of the Eastern Sector.
Colonel Mustang started his coup around the same time in central itself, with the aid of the Briggs soldiers and their tank.
The tank was transported in pieces to the large family estate of Major General Armstrong. The tank was assembled on the estate and then used to spearhead the advance to Central Command, the headquarters of the Central Army of Amestris and the seat of Führer King Bradley. The Central Command did know about the existence of the Briggs Tank, as did the Central Commandos tasked with stopping the Briggs advance on Central Command, but they did not expect the Briggs Soldier to have a tank at their disposal during the coup. As such, the central soldiers, already taken by surprise by the Briggsian revolt, were now also taken by surprise by the appearance of the Briggs Tank. The Tank reached Central Command and fired an HE projectile on its walls. Not long after, the Briggsian soldiers took over Central Command.
The Briggs Tank was positioned on top of the stairway to the Central Command main gate, in order to hold back the Central Soldiers who might try to recapture Central Command. Not long after the Briggsian soldiers celebrated the success of their coup, they were abruptly interrupted by Führer King Bradley over the radio, announcing his survival of the bombing and his return to Central to personally assume command and to squash the coup. King Bradley arrived at the main gate of Central Command stating:
‘Why should I enter my own palace from the back entrance’.
King Bradley was the homunculus Wrath, an extremely skilled leader and a one-man army, raised from birth to lead the country. Realising the danger of King Bradley, Captain Buccaneer ordered his tank squad to pull back, but King Bradley, being a very powerful homunculus, charged immediately at the tank squad on his own.
The Briggs Tank tried to gun down King Bradley on his approach, but missed all their machine gun fire. One main gun round was fired but missed as well. At this point, King Bradley reached the tank, and stabbed the driver by breaking the glass of the vision port with his sword. The Co-driver tried to run King Bradley over, but King Bradley cut the tracks apart and subsequently, threw a grenade through the broken vision port of the driver. The grenade detonated and the Briggs Tank was taken out by the homunculus.
No further usage is known of the Briggs Tank.
Realism
The Briggs Tank is, for the time period it was developed and used (around 1914), not a realistic vehicle. The hull stays true to its era and is based on the British Mark I tank. The turret is mostly based on a Ferdinand casemate, a vehicle that was built almost 30 years later. Its turret and armament are too large and heavy for its time, especially when considering this is seemingly the very first tank of the Amestrian State Army and possibly the world. At the same time, Amestris was a very advanced country technology and productionwise. It would not be impossible for them to actually pull this design off. So compared to the development of tanks in our timeline, it would be unrealistic, considering the potential of Amestris, it might be possible.
The Briggs Tank of the FMA Manga might be unrealistic when considering the era it was built in, but, overall, it is not a bad design for a fantasy tank. By basing it on actual vehicles, the author managed to draw a reasonable design. The main issues with the tank are the gun, and the bow machine gun. The gun seems to be a very high calibre when looking at the drawing, but the actual calibre is unknown. Lastly, the bow machine gun can easily be fixed by not mounting it in a tube but by using a ball mount for example.
Other Tanks
In the FMA manga, another drawing is seen when the protagonists get a tour around Fort Briggs. The drawing is a bit confusing, as it suggests that the casemate is mounted more towards the front of the hull. But considering the size of the humans, compared with the suspension in the front of the drawing, the casemate/turret and the hull are presumed to be separated.
The hull and suspension at the front of the drawing are identical to the German Minenräumpanzer 3. The hull in the manga is nearly identical to the actual vehicle, except for a few very minor details at the front hull.
The casemate/turret has a very Maus-like gunshield, but the rest of the turret bears more resemblance to the Maus II turret. The Maus II turret came into existence after concerns about the curved Maus turret, which might deflect projectiles into the hull top. As such, the frontal turret would be an angled plate instead of a curved plate, and the gun mount was altered as well among other things. The FMA Manga turret seems to have incorporated the main features of the Maus II turret regarding the armor profile and the gun mount. The gun shield seems to have more resemblance to the original Maus turret.
Briggs Tank FMA: Brotherhood (2009)
The first appearance of the Briggs Tank in the FMA: Brotherhood anime is in episode 34, which shows the construction facility, including a few Briggs tanks under construction. No other type of tank is shown in the anime.
The development of the Briggs Tank in FMA: Brotherhood is the same as the development of the Briggs Tank in the Manga.
The Briggs Tank in Detail
Like the manga, the actual specifications of the Briggs Tank are unknown, and are analysed in the same way. The Briggs Tank is about 7 meters (23 feet) long, 4 meters (13.1 feet) wide, and 2.5 meters (8.2 feet) tall. As the Briggs tank is very reminiscent of the Panzer IV, it is estimated to weigh in between 18 to 25 tonnes (18.8 to 27.5 US-tons) combat-ready. The tank is operated by 5 crew members, consisting of the Commander (left turret rear), Gunner (in front of the commander in the turret), Loader (right of the gunner in the turret), Driver (left front hull), Co-driver/Hull Machinegunner (right front hull).
Hull
The hull of the Briggs Tank seems to have multiple inspirations. The most obvious inspiration is the Panzer IV, but the VK 30.01 (H) might also have been an inspiration. For the hull, the Panzer IV seems to be more likely, as the frontal hull angling, the driver’s vision slit and the hull machine gun, the engine bay, and the vision slits on the side of the hull for the co-driver and driver correspond to it. The KV-1 is also recognised in the Briggs tank, mainly because of the frontal armor profile. The exhausts on the rear sides of the hull are somewhat reminiscent of the exhaust on the Centurion. The sides of the hull are protected with side skirts, just like the Panzer IV.
The armor is most likely, just like the Panzer IV, welded together from multiple large steel plates. No riveting is shown at all, which supports this theory. As with the Manga Briggs tank, the armor and the exact angling are unknown. Since this is the first armored vehicle of Amestris, the armor values might be close to the very first Panzer IV version, the Panzer IV Ausf. A. This would mean that the Briggs Tank has a frontal hull armor of 10 to 14.5 mm (0.4 to 0.57 inch), 10 to 14.5 mm (0.4 to 0.57 inch) on the sides, 14.5 mm (0.57 inch) on the rear, and 8 to 10 mm (0.3 to 0.4 inch) armor on the top and bottom of the hull. The frontal armor thickness is somewhat supported by a shot close up on the hull machine gun. In this close-up, the armor does not look too thick. By measuring the length of the hull machine gun of the Panzer 4 and the Briggs Tank, and through the use of ratios, the frontal hull thickness is very roughly estimated to be around 20 mm (0.8 inch) thick.
The Briggs tank has a bow machine gun on the front right of the vehicle, fired by the co-driver. The driver is located on the front left side of the vehicle. The Briggs tank has towing hooks on the front side of the vehicle and two headlights.
The engine is located in the rear of the hull and two exhausts are located on both sides of the rear hull. Interestingly, another muffler is located on the rear of the vehicle, very much reminiscent of the Panzer IV muffler.
Mobility
The engine of the Briggs Tank is unknown, but since the vehicle seems to be based on the Panzer IV, an estimation can be made on the specifications. The Panzer IV Ausf. A had a Maybach HL 108TR 230 hp engine, while the Panzer IV Ausf. J had a Maybach HL 120 TRM 320 hp engine. It is more likely for the Briggs Tank to have an engine of around 230 hp, as this is Amestris’ first tank but it potentially has an engine with around 230 to 320 hp. The engine is mounted in the rear of the vehicle, and the transmission is located in the front of the vehicle.
The suspension of the Briggs Tank does not bear resemblance to either the Panzer IV’s suspension or the interleaved roadwheel suspension found on other German tanks. It seems to resemble a torsion bar suspension instead. The road wheels do seem to bear some overal resemblance with KV-1 road wheels. It has 5 road wheels on each side and the drive sprocket is located in the front of the vehicle.
The vehicle is shown to be very mobile, being able to climb a slope of in between 30 and 37 degrees at high speeds.
Turret
The turret of the Briggs tank seems to share multiple inspirations. Its main inspiration seems to be the VK 30.01(H) and Panzer IV turrets. This is mainly because of the general shape of the turret, and the vision ports located on the sides of the vehicle. The vision ports of the VK30.01 (H) seem to be integrated with the side turret hatches of the Panzer IV. Its turret hatch configuration resembles the layout of a Tiger 1. The commander’s cupola looks more or less like a generic cupola, but with the Tiger 1 layout, could be identified as a late Tiger 1 cupola. Another hatch is located on the rear of the turret, which might be used to load and eject shells.
Armament
Like the rest of the specific components, the armament of the Briggs Tank is unknown, but a reasonable origin of the Briggs Tank’s main gun can be found in the anime. The 7.5 cm Pak 40 anti-tank gun is shown at multiple points throughout the series. They are used during the Ishvalan War of Extermination, but also in the defence of Fort Briggs. As such, it can be speculated that the armament of the Briggs Tank is a 7.5 cm which was converted from the 7.5 cm Pak 40, just like the Panzer IV’s main gun. The gun is about 3.5 meters (11.5 feet) long excluding the barrel length in the turret, which is about the same length as the Panzer IV’s 7.5 cm KwK 40 L/48 gun.
The available ammunition of the cannon is unclear. In a scene, the commander of Fort Briggs orders her soldiers to remove the fuses from the shells. This could suggest that the only type of ammunition is APHE, as the explosions during the coup détat of Colonel Mustang are relatively small.
The hull machine gun is most likely an M1919 Browning HMG. This is because the soldiers of Fort Briggs are shown to use this type of machine gun during the coup d’état. It would be logical for the Briggs Tank to use this machine gun as well.
Service
The service of the FMA: Brotherhood Briggs Tank is nearly identical to the service of the Manga Briggs Tank. The only real difference is how the events occur during the battle between King Bradley and the Briggs Tank. While the Briggs Tank is on top of a large staircase in the manga, the Briggs tank in the anime is stationed right in front of the stairs and the lift to the top of Central Headquarters.
When King Bradley engages the tank in battle, he manages to cut a tank shell in half with his sword after it was fired upon him (an obviously impossible feat in the real world) and proceeds to advance on the tank, while deflecting hull machine gun fire with his sword. As a panic reaction, the crew of the tank starts reversing at high speed to the staircase, nearly driving over two fellow Briggs soldiers. Still reversing on the ramp to Central Headquarters, King Bradley still manages to evade the tank fire upon him. By using the blast of a shell, King Bradley launches himself to the tank and stabs the driver through the driver’s vision port. While the co-driver is ordered to take over, King Bradley cuts through both tracks of the Briggs tank. The tank slides to the side as a result, smashing the main gun into a wall. The commander of the tank opens his hatch in an attempt to shoot King Bradley with his pistol but is killed in the attempt by King Bradley. King Bradley subsequently throws a grenade in the tank and destroys it.
Realism
As with the manga Briggs Tank, this version is also unrealistic for its time period, around 1914. The vehicle is almost completely based on a tank developed in 1935, and some specific features, like the main gun and side skirts, appeared a lot later as well. Considering this is seemingly the first tank of Amestris, and possibly the world, the advancements in this tank are too great. From utilising a torsion bar suspension, its weight, its main gun, and side skirts, the Briggs Tank in the anime is overal too modern. But this is when one compares the tank to our time and development. Amestris in the Brotherhood anime is shown to have technologies like panzershrecks and 7.5 cm Pak 40 guns, eventhough their enemies don’t seem to own any tanks. At the same time, some of the manufacturing processes which would have been used for the guns of Amestris are well into 1940s to 1950s technology. Overal, when one takes the technology of Amestris into account, it would definately be possible, allthough some design steps maybe a bit too much for a first attempt. Compared to the progression of tank development in our timeline, it would not be realistic.
Apart from its era, the anime Briggs tank is a realistic vehicle. This is not surprising since it is practically a redesigned copy of a Panzer IV, but integrates various other German tank features. The Anime Briggs Tank is a good fantasy tank, maybe not very original, but also not residing in the realms of absurdity. The artists can be commended for their research and integration of German vehicles, which helps to further strengthen the link between Amestris and Nazi Germany, which is a much more important theme in the Anime than in the original Manga.
Battle Tank FMA (2003)
The first appearance of the Battle Tank in the FMA anime is in episode 39. In a brief moment, a crew is seen performing maintenance on a Battle Tank. No other type of tank is shown in the anime.
Nothing is known about the development of the Battle Tank.
The Battle Tank in Detail
The specifications of the battle Tank are unknown and are analyzed in the same manner as the previous vehicles. The Battle Tank is around 3.6 meters (11.8 feet) long, 2.5 meters (8.2 feet) wide, and 2.5 (8.2 feet) meters tall. The Battle Tank is almost identical to the Renault FT, as such, it is estimated to weigh 6.7 tonnes (7.4 US-tons) combat-ready. The tank is most likely crewed by 2 crew members, like the Renault FT, consisting of a Commander/Gunner (turret) and Driver (front hull).
Hull
The hull of the Battle Tank is pretty much a copy of the Renault FT. For this reason, it is estimated to have the same armor as the Renault FT. As such, it is estimated to have 16 mm (0.6 inch) on the front, sides, and rear of the hull, and between 6 to 8 mm (0.2 to 0.3 inch) on the top and bottom of the hull. The armor is most likely riveted together, like on the Renault FT. Some scenes show a few rivets on several places on the hull to support this theory.
The driver is located in the front of the vehicle. In contrast to the Renault FT, it looks like the driver cannot enter the vehicle through a front hull hatch, but only through the turret. An exhaust is located on both sides of the tank, and the engine is located in the rear of the vehicle.
Mobility
The engine of the Battle Tank is unknown, but based on the Renault FT, it probably has a 4 cylinder 35 hp engine. In the Anime, the vehicle is seen to move roughly at the same pace as infantry, but if this is its maximum speed is unclear.
The suspension is similar to the Renault FT’s coil and leaf spring combination suspension. The tank uses multiple road wheels on the bottom.
Turret
The turret is, together with the armament, the only part that differs more from the Renault FT. The turret is quite tall, an estimated 1 meter tall, but retains the overall shape of the Renault. It seems to have a small hatch on the rear, potentially for ejecting shell cases. It has a single pericope in some depictions, located at the front of the commander’s cupola. The Battle Tank’s turret also seems to have a plate on the side of the turret in some depictions. Its purpose is unknown. The armor is estimated, based on the Renault FT, to be 22 mm (0.9 inch) all-round, and 8 mm (0.3 inch) on the top of the turret.
Armament
The armament of the Battle tank is unknown. Based on different measurements and ratios, it seems to mount a 100 mm cannon. This cannon would probably be a howitzer-type cannon. The ammunition could potentially consist of HE and Canister rounds.
Alternatively, it could be armed with the Puteaux 37 mm cannon of the Renault FT. This would be a more realistic gun. The Battle Tank could then have APHE, HE, and Canister rounds at its disposal.
No other armaments are shown in the anime to give any leads on possible sources for the Battle Tank’s gun.
Service
As the Battle Tank is available in reasonable numbers and the Amestrian Army operates it as a separate division, it can be concluded that the Battle Tank is already in service for an extended period of time and that the Amestrian Army has gained some experience in using tanks. Furthermore, the Battle Tank is shown to be used with motorized infantry support, which suggests that at least early steps are taken in combined arms warfare.
In the Anime, the Battle Tank is first shown in the preparations to assault the city of Lior (Liore in the FMA: Brotherhood Mange, originally Reole). The assault had multiple reasons. The Amestrian Army had gained intelligence that a large transmutation circle was being made, and they sent the State Alchemist, and protagonist, Edward Elric to investigate the circle.
In addition, a murderer named Scar (because of a cross-shaped scar on his forehead) was sighted in the city. Scar was a serial killer who specifically murdered State Alchemists to exact revenge for his deceased brother and near-exterminated race called the Ishbalans (Ishval in FMA: Brotherhood), and was one of the most wanted criminals in Amestris.
A third reason was a brief conflict incited by Lior under control of a theocratic government ruled by Father Cornello. It was a brief but bloody civil war which resulted in the defeat of Lior and its rebelling allies. There was still unrest in Lior as the civil war ended quite recently, and as a result, the commander of the assault, Colonel Frank Archer, was planning to invade Lior with the hope of Lior retaliation, so that he had a justification to exterminate the Lior people and race.
Around 7000 troops were gathered near Lior, which were supported by at least 18 Battle Tanks. At the arrival of Lior, the Amestrian Army spots Scar, and Colonel Archer subsequently orders his Battle Tank Division to surround Lior, and his troops to enter the city. This could mean that the Amestrian Army has experience with tanks in urban warfare, and have concluded that their Battle Tanks are not suited to fight in urban terrain.
Not long after the assault of Lior has begun, State Alchemist Edward Elric reaches the Amestrian Army near Lior and has a brief argument with Colonel Archer about not accepting Lior’s surrender. Edward Elric identified the large transmutation circle to be one to create a philosopher’s stone. The activation of such a transmutation circle would result in the death of all persons within the circle and the creation of a philosopher’s stone consisting of human souls. This stone is an all-powerful Alchemy enhancing stone, giving the Alchemist the ability to ‘’circumvent’’ the laws of Alchemy and giving him immense power.
When the troops entered Lior, the Lior inhabitants had already fled the city as part of Scar’s plan. Not long after, Scar activates the transmutation circle, and, as a result, it is suggested that almost all of the 7000 soldiers participating in the assault were killed and turned into a philosopher’s stone. If any tank crews were killed in the assault is unknown, but highly unlikely, as they were ordered to surround the city, and thus were not within the transmutation circle.
Later, in the Fullmetal Alchemist: The Conqueror of Shamballa movie, set immediately after the events of the Anime, tanks are used in the defence of Central City from Thule forces.
The FMA Thule Society is based on the real-life Thule Society, which operated during and after World War 1 until around the late 1920’s. They were a society who supported the DAP (Deutsche Arbeiterpartei, German Workers’ Party), which would later become the Nazi party.
In the 2003 FMA universe, our reality is a counter reality to the FMA reality. Where our main science is physics, FMA’s main science is Alchemy. Due to certain events in the Anime, the story starts to overlap both realities. The Thule Society, led by Dietliende Eckhart, wanted to return power to Germany after the defeat of World War 1. They hoped to conquer the FMA reality and, as a result, gain valuable resources and heighten the political power of Germany.
Dietlinde Eckhart invaded the FMA Reality and wreaked havoc on the Amestrian soldiers stationed in Central City. With the help of her airship and her soldiers, they try to take Central Command. The Thule forces are met by soldiers under command of Colonel Mustang, and they manage to defeat the Thule Forces. In a very brief scene, 5 Battle Tanks are seen firing at the Thule Soldiers.
Not long after, Edward Elric, Alphonse Elric, and Colonel Mustang defeat Dietline Eckhart and her soldiers with the help of the Amestrian soldiers guarding Central Command.
No further usage of the Battle Tank is known.
Realism
The Battle Tank is the most realistic vehicle of the three adaptations. It is more or less identical to the Renault FT, and as such, is realistic in the setting of FMA. The only questionable components are the tall turret, and its potentially high caliber gun. Apart from those two somewhat minor issues, the Battle Tank is a realistic vehicle that fits the time and the setting of the FMA Universe.
Although not particularly original, the artists made a good decision by using the Renault FT as a base template for the vehicle. For the viewers who know more about tanks, and as a result recognise the Renault FT design, it added more immersion to the overall FMA setting. In this aspect, it is a very well done tank in an Anime. Where the Briggs Tank of the FMA: Brotherhood Anime strengthens the linkage between Germany and Amestris, the Battle tank strengthens the linkage with the setting.
Conclusion
Of the three adaptations, the FMA Anime 2003 is the most realistic. By using a more or less identical Renault FT, the artists of the Anime have used a realistic tank that fits in the setting of FMA, and for the tank enthusiasts, adds to the overall immersion.
The FMA: Brotherhood Briggs Tank is the next most realistic tank in terms of practicality. Certain design aspects would be unrealistic, since it is suggested to be the first tank of the FMA: Brotherhood universe. By combining multiple aspects of German tanks and staying with these designs, the artists have managed to design a tank that looks realistic and serves to intensify the connection between Amestris and Germany.
The Manga tank is the least realistic, with its huge cannon, turret, and questionable lay-out. Aside from its realism, Hiromu Arakawa, the artist and writer of the manga, did a good job in incorporating real designs into a tank.
Overall, all the adaptations artists can be commended for their usage of design aspects of real vehicles. This shows that they put thought in how a tank is supposed to look, instead of just drawing something that resembles a tank, but is completely ridiculous. The attention in something like a tank for the adaptations adds to the quality of the series. It adds to the immersion, and in the instances of the animes, it helps strengthen certain aspects of the overall setting. As such, the tanks have a real contribution to the adaptations, albeit only for tank enthusiasts.
Illustrations
Sources
Fullmetal Alchemist 2003 Anime
Fullmetal Alchemist: The Conqueror of Shamballa
Fullmetal Alchemist: Brotherhood
Fullmetal Alchemist Manga https://fma.fandom.com/wiki/Main_Page
Federative Republic of Brazil (1976)
Tracked Self-Propelled Multiple Rocket Launcher – 1 Prototype Built
In 1973, Brazil began developing the X1 light tank, which was completed later that year. From there, the vehicle would spawn multiple variants, from bridge-laying vehicles to anti-aircraft vehicles. Another variant of the X1 combined the Brazilian research in rocket development, which had started in 1949, with the Brazilian advancements in the X1 project into a tracked self-propelled multiple rocket launcher vehicle, also known as the XLF-40. With this project, Avibras would gain a more prominent role within the defence industry and it would eventually lead to the renowned ASTROS 2 Artillery Saturation Rocket System.
Brazilian rocket development
In 1949, the Escola Técnica do Exército (ETE) (English: Army Technical School) initiated the Brazilian research of rockets, in line with developments from other major countries of the time. The first project was the 114 mm F-114-R/E rocket, which showed promising results. The F-108-R rocket system was then developed in 1956, which could fire multiple rockets and was mounted on a ¾ ton Willys Overland Jeep designated Fv-108-R.
In 1961, the company Avibras Aerospacial SA was founded in São José dos Campos (SP) by engineers of the Centro Técnico da Aeronáutica (CTA) (English: Aeronautical Technical Center). Avibras would develop Brazil’s first solid synthetic propellant, which would propel them into the rocket and missile industry.
The first major step for Avibras and the CTA was their participation in the Experimental Inter-American Meteorological Rocket Network project or EXAMETNET. This was a project led by the United States to acquire meteorological data for the entire American continent. The US started working together with countries like Argentina and Brazil by providing them with the Arcas rocket to carry out measurements at heights between 20 to 80 km. With Brazil’s participation in the project, the CTA acquired the technology and design of the Arcas rocket and went on to start developing the Sonda 1. The Sonda 1 was a two-stage rocket for which the general idea and technology were copied from the Arcas, but were redesigned for a larger rocket. Although the Sonda 1 itself would not be a success, its design proved fundamental.
In 1965, the CTA transferred the technology of the Sonda rocket to Avibras. With this transfer, Avibras effectively became the most important manufacturer of rockets and missiles in Brazil, as Avibras was responsible for the manufacture of the Sonda 1. After the Sonda 1 project, the CTA started developing the Sonda 2, which was again manufactured by Avibras in the late 1970s. From this point onward, Avibras would, together with the CTA, Instituto de Pesquisas e Desenvolvimento (IPD) (English: Research and Development Institute), and the new Instituto Militar de Engenharia (IME) (English: Military Institute of Engineering), renamed after a merger between the ETE and IMT in 1959, started developing ground-to-ground and air-to-ground rocket systems. One of these rockets was the X-40, which was developed in 1972.
The X-40 was a 300 mm rocket (rockets are unguided, missiles are guided) with a length of 4.45 meters (14.6 feet), weighing 550 kg (1,213 lb), of which a payload of 150 kg (331 lb), and a range of 65 km (40.4 miles). It used a solid propellant as fuel and was manufactured by Avibras. An interesting fact was that this was the first time the Brazilian engineers had used computers to make the calculations for rocket development.
With the development of the X1 family, the promising results of the X-40 rocket, and seeing this as a way to provide more firepower and mobility to the Brazilian artillery units, the IPD initiated the design of a tracked self-propelled multiple rocket launcher, which received the designation Carro de Combate Lançador de Foguetes X-40 (English: Combat Car X-40 Rocket Launcher).
The X1 project
The first X1 vehicle was developed and presented at the Brazilian Independence Day Parade on September 7th of 1973. The X1 was a modernization project of the M3 Stuart, carried out by the Parque Regional de Motomecanização da 2a Região Militar (PqRMM/2) (English: Regional Motomecanization Park of the 2nd Military Region), together with Bernardini and Biselli, two Brazilian private companies. The PqRMM/2 was responsible for the development of the wheeled vehicles, but also for the tracked vehicles of the Brazilian Army at the time, and was under the supervision of the Diretoria de Pesquisa e Ensino Técnico (DPET) (English: Army Research and Technical Educational Board), which coordinated the projects.
The tracked vehicles were researched and developed by a team of engineers within the Army and PqRMM/2, which were part of the Centro de Pesquisa e Desenvolvimento de Blindados (CPDB) (English: Centre for the Research and Development of Tanks). The CPDB was a study group of Army engineers which analyzed the possibilities of producing tanks domestically. The first goal was to develop a new family of light tanks using the M3 Stuart as its basis. One of the vehicles which would form part of what we now know as the X1 family, was the XLF-40.
The XLF-40
With the success of the X1 project and the completion of the X-40 rocket, the Brazilian Army decided to initiate the development of a rocket system for the X1. The IPD made the first sketches of the Carro de Combate Lançador de Foguetes X-40 (English: Combat Car X-40 Rocket Launcher), which were presented on July 20th, 1976. Further design and construction were immediately initiated in an attempt to build the new vehicle before September 7th of the same year, so it could make an appearance on the yearly Independence Day parade, together with the X1A1 and the XLP-10.
The XLF-40 would receive three different designations during its development, with its proposal calling it Carro de Combate Lançador de Foguetes X-40, which would be simplified to Carro Lançador Múltiplo de Foguetes (Multiple Rocket Launcher Vehicle). Finally, it received the designation XLF-40. The X referred to it being a prototype, the L to Lançador (English: Launcher), the F to Foguetes (English: Rockets), and the 40 to the X-40 rockets used. Eventually, the full name would be Viatura Blindada Especial, Lancador de Foguetes, XLF-40 (VBE LF XLF-40) (English: Special Armored Vehicle, Rocket Launcher, XLF-40).
The development of the XLF-40 would be carried out by multiple companies, of which Avibras, Bernardini, and Biselli were the most important. Bernardini and Biselli were responsible for the conversion of the hull and installation of the suspension, while Avibras manufactured the rockets.
One of the requirements was that all the systems were completely operable from within the vehicle. The aiming and the launching of the rockets were controlled through radio systems. The rockets could be fired independently or in a volley. To provide a better surface to fire from, the XLF-40 had four outriggers, two on each side, which were operated by hydraulic pistons on each leveling system. These outriggers made the XLF-40 a more stable platform to fire from, increasing its accuracy. Another interesting development was the installation of the TRANSIT global positioning system to better locate the vehicle. This GPS system would help the crews to better estimate the firing arcs of their rockets and be more accurate. An M3A1 Stuart hull was selected to be converted to the XLF-40.
The XLF-40 would only be armed with its rockets and personal weapons for the crew, as the machine gun for the co-driver from the M3 Stuart was removed to provide the same dual hatch as for the driver. This meant that the co-driver had a larger space to enter or exit the vehicle. This style of hatches was first used on the X1 prototype vehicle, but would only be carried out on the XLF-40 and the XLP-10 vehicles. The construction of the XLF-40 prototype was completed in less than 2 months and was able to be presented during the September 7th, 1976 Independence Day Parade.
XLF-40 hull origin theory
In the X1 article, the writer proposed a theory to what may have happened with the X1 prototype after it was completed. This theory suggests that the hull might have been repurposed. Besides the X1, a bridge-laying vehicle designated XLP-10 and a rocket launching vehicle designated XLF-40 were built. Both these variants would use the two hatch opening for the co-driver instead of a hull machine gun. What is interesting is that the XLP-10’s and all production X1’s used a single front side plate and the XLP-10’s missed a characteristic hook on these plates. The XLF-40, though, used the exact same double front side plates design as the X1 prototype and also offered the hook. Additionally, both the X1 prototype and the XLF-40 were converted from an M3A1 Stuart, identifiable from the rear. Considering the X1 prototype was trialled in 1974, the XLF-40 was built in 1976 and the original Engesa turret of the X1 prototype was repurposed for the EE-9 project, it is very likely they repurposed the X1 prototype hull for the XLF-40 prototype. Just like the prototype turret, this makes perfect sense to not waste an otherwise perfectly fine hull and to cut costs in what was effectively a technology test bed.
With these arguments, the writer hopes to have sufficiently proved his theory that the X1 prototype hull was repurposed for the XLF-40, but would like to reiterate that this is just a theory and only indirect evidence and photographs point towards this possibility. No direct evidence has been found to verify this theory.
XLF-40 in Detail
The XLF-40 weighed 16.6 tonnes combat-loaded (18.3 US tons) and 15 tonnes (16.5 US tons) without rockets. It was 5.98 meters (19.6 feet) long, 2.74 meters (9 feet) wide, and 2.54 meters (8.3 feet) tall. It had a crew of three, with the driver located on the front left of the hull, the co-driver on the front right of the hull, and the commander probably positioned somewhere under where the turret originally was positioned, although there is no confirmation of this.
Hull
The hull of the XLF-40 was a slightly lengthened and modified M3A1 Stuart hull. As such, the overall protection for the XLF-40 hull remained the same as that of the M3. The thickness of the plates which were used to lengthen the hull is unknown. The upper front plate of the XLF-40 had an armor thickness of 38 mm (1.5 inch) at 17 degrees vertical, a middle front plate of 16 mm (0.6 inch) at 69 degrees, and a lower front plate of 44 mm (1.7 inch) at 23 degrees. The frontal cheek plates transitioning to the side plates were 28 mm (1.1 inch) thick. Its sides were 25 mm (1 inch) thick and angled at 10 degrees from vertical, while at the engine bay the sides consisted of two plates of 25 mm spaced from each other. This is because in the crew compartment, a hole was grinded out of the original plates for use as stowage, while this did not happen at the rear. The rear armor was the same as the M3 Stuart, being 25 mm (1 inch). The top plate was 15 mm (0.6 inch) thick and the floor plate gradually decreased in thickness from 13 mm at the front to 10 mm (0.5 to 0.4 inch) in the rear.
The rest of the XLF-40 had a very similar layout as the Stuart. It had two headlights, one on each side of the front mudguards, two towing hooks on the front hull, two driver style double hatches and, as a result, no hull machine gun.
The XLF-40 had two hydraulic pistons on the front hull, one on each side. These pistons were fixed on a pivot, which allowed them to turn facing the ground when the pistons were utilized. The feet on which the XLF-40 was stabilized had a rotating bar attached to them and to the hull, which caused the pistons to face the ground as the rod of the piston made a complete stroke.
The rear curved plate was altered to make room for the rear hydraulic cylinders. The hydraulic cylinder was mounted to the rear by cutting a hole in the curved M3A1 rear plate and sticking the cylinder through it. All the hydraulics of the XLF-40 were powered by the original M3A1 Stuart hydraulic system.
Mobility
The XLF-40 was powered by a Scania-Vabis DS-11 A05 CC1 6-cylinder in-line diesel engine. This engine produced 256 hp at 2,200 rpm, giving the vehicle a horsepower per tonne ratio of 15.4. It used the same, but revised and locally produced, 5 forward and 1 reverse gearbox, transmission, and differential as the original Stuarts. The XLF-40 would have a top speed of about 55 km/h (34 mph) on roads, but would most likely be much lower when it was armed with the X-40 rockets. The vehicle had an operational range of 520 kilometers (323 miles).
The XLF-40 used a copied and slightly altered VVS suspension system from the 18-ton M4 artillery tractor. It had 4 road wheels divided over two bogies, with 2 bogies per track, two return rollers on each side, a drive sprocket in the front, and an idler wheel on the rear. The 18-ton M4 suspension gave the vehicle a ground pressure of around 0.59 kg/cm2 (8.4 psi). It had an on-ground track length of about 3.22 meters (10.6 feet) and could cross a trench of 1.2 meters (3.9 feet).
Turret and Armament
The turret was replaced by a single plate on which the rocket frame and the needed hydraulics were mounted. This single round plate used the same 1.6 meters (5.25 feet) turret ring diameter as the rest of the X1 family. On the rear of the plate were two hatches for the crew, located in between the rocket rails.
A frame was built on top of the plate, on which the hydraulic cylinders were located. The rods of these cylinders were fixed to the launching platform so that the rockets could be fired at the needed angle. The launching platform would rest on the frame during travel. Over the years, there seems to have been some development regarding the location of the hydraulic cylinders for the launching platform. The cylinders seem to have been placed much more forward from the launching platform in the early development stages. In later stages, the cylinders seem to have been placed much closer to the hinge point of the launching platform, potentially enabling the rockets to be fired from much steeper angles.
Resting on top of the frame was the launching platform, from which the rockets would be aimed and fired. The frame seems to have been constructed from heavily perforated steel profiles. The holes in the frame were probably meant to save weight, so that smaller hydraulics could be used. The launching platform was 5.5 meters (18 feet) long and between 1.8 to 2.4 meters (5.9 to 7.9 feet) wide. It had three rails from which a rocket could be fired. Each rail had two clamps attached to them in order to clamp the rocket to the rails during travel.
Initially, the mounting point of the hydraulic cylinder was located in the middle of the launching rails but later seems to have been repositioned towards the rear of the platform due to the relocation of the hydraulic cylinder. The hydraulic cylinders enabled the launching platform to be angled and give the rockets the trajectory to hit their target. The rockets were fired perpendicular from the hull. This was done to provide the launching platform with the needed space to angle the rockets, which is seen to be done at a near 90-degree angle with the rockets aiming almost straight up the sky.
The XLF-40 was armed with 3 X-40 rockets. These rockets had a range of 65 km and used solid propellant as their fuel. The rockets were about 4.45 meters (14.6 feet) long and had a diameter of 300 mm. The rockets weighed 550 kg (1213 lb) each with a 150 kg (331 lb) payload. The rockets could be fired both simultaneously and independently from each other. The XLF-40 had no further armament.
Fate
After the XLF-40 was presented in the Independence Day Parade in 1976, Brazilians would continue testing and improving the vehicle until the early 1980s. It would be tested at the Marambaia Proving Ground in Rio de Janeiro, where it would fire its rockets towards the sea.
The XLF-40 would mostly end up as a testbed more than anything else. It would have a few issues, some of them with the launching platform, but these were said to never have been fully resolved. These issues were part of the reason why the project would not be progressed upon further. In 1981, with the knowledge acquired from the XLF-40 project, Avibras developed the ASTROS 1 rocket system for Iraq, which would eventually lead to the successful ASTROS 2 rocket system that is operated by the Brazilian Army, among others. The development of the ASTROS rocket systems probably contributed to the eventual cancellation of the XLF-40 as well.
With the cancellation, the XLF-40 was added to the Conde Linhares Military Museum collection in Rio de Janeiro at an unknown date.
Conclusion
In the end, the XLF-40 can be described as a testbed for rocket systems for which potential military service would have been a bonus. It incorporated some relatively advanced technologies, such as the TRANSIT GPS, which would go on to enable Avibras to develop a much more advanced rocket system. The Brazilian Army did not seem initially convinced by the potential of rocket systems after the XLF-40. It would take Brazil until the 1990s to buy the ASTROS system, 10 years after its first conception. This might also have been because the need and money were not there for the expensive system.
The XLF-40 was fundamental for Avibras as a company, and paved the way for the successful ASTROS rocket systems, which were sold by Avibras to countries such as Saudi Arabia, Iraq, Brazil and Indonesia, among others. The ASTROS would become one of Brazil’s most successful and lucrative weapon systems, still being ordered to this day.
Illustrations
Specifications XLF-40
Dimensions (L-W-H)
5.98 (19.68 feet) x 2.74 (9 feet) x 2.54 meters (8.33 feet)
Total weight
16.65 tonnes (18.35 US tons)
Crew
3 (Driver, Co-driver, Commander)
Propulsion
Scania-Vabis DS-11 A05 CC1 6-cylinder in-line 256 hp diesel engine
Suspension
Bogie suspension
Speed (road)
55 kph (34 mph)
Operational range
520 km (323 miles)
Armament
3 X-40 Rockets
Armor
Hull
Front (Upper Glacis) 38 mm (1.5 inch) at 17 degrees
Front (Middle Glacis) 16 mm (0.6 inch) at 69 degrees
Front (Lower Glacis) 44 mm (1.7 inch) at 23 degrees
Sides 25 mm (1 inch)
Rear 25 mm (1 inch)
Top 15 mm (0.6 inch)
Floor 13 to 10 mm (0.5 to 0.4 inch)
Turret
25 mm (1 inch) allround
Production
1 Prototype
Special thanks to Expedito Carlos Stephani Bastos, the leading expert of Brazilian armored vehicles https://ecsbdefesa.com.br/, Jose Antonio Valls, an Ex-Engesa employee and expert in Engesa vehicles, Paulo Bastos, another leading expert of Brazilian Armored vehicles and the author of the book on Brazilian Stuarts, and Guilherme Travassus Silva, a Brazilian with whom I was able to endlessly discuss Brazilian Vehicles and who was always willing to listen to my near-endless ability to talk about them.
Sources
Brazilian Stuart – M3, M3A1, X1, X1A2 and their Derivatives – Hélio Higuchi, Paulo Roberto Bastos Jr., Reginaldo Bacchi
Blindados no Brasil – Expedito Carlos Stephani Bastos
Lançador de Foguetes XLF-40 – A Artilharia Sobre Lagartas – Expedito Carlos Stephani Bastos
Uma realidade brasileira: Foguetes e mísseis no Exército Brasileiro 1949-2012 – Expedito Carlos Stephani Bastos http://www.lexicarbrasil.com.br/
Personal correspondence with Expedito Carlos Stephani Bastos
Personal correspondence with Paulo Roberto Bastos Jr.
TM 9-785 18-Ton High Speed Tractors M4, M4A1, M4C, and M4A1C – US Army April 1952. Stuart: A history of the American Light Tank, Volume 1 – R.P. Hunnicutt
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