Cold War Belgian Prototypes Archives

ACEC Cobra Tank – Cobra 25 and 90

Kingdom of Belgium (1977-1990) Light Tank – 1 Built From AFV to tank Despite the lack of successful orders for the APC/AFV version of the Cobra, the ACEC Cobra’s powertrain was successful and compact enough to warrant a further attempt to enter the armoured vehicle market, this time in the light tank category. In order …

ACEC Cobra IFV

Kingdom of Belgium (1977-1990) Infantry Fighting Vehicle – 4 Built Belgium is not the first country to leap to mind for most people when they think of tanks or armored fighting vehicles, yet it has produced a few particularly interesting designs over the years. One of the these, which is virtually unknown, is the ACEC …

ACEC Cobra Tank – Cobra 25 and 90

From AFV to tank

Despite the lack of successful orders for the APC/AFV version of the Cobra, the ACEC Cobra’s powertrain was successful and compact enough to warrant a further attempt to enter the armoured vehicle market, this time in the light tank category.
In order to make a tank which was still as small as possible but capable of packing a big punch ACEC redesigned the Cobra hull. This was the final version of the hull produced and involved a complete rearrangement inside although the wheels, track and suspension arrangement remained the same. The single driver was now located centrally where the engine used to be and the engine and motors were moved to the back of the vehicle in a conventional arrangement for an unconventional tank. It still retained the electrical transmission meaning it was still very light and had excellent acceleration but now came in a light tank, and a reconnaissance version.
The reconnaissance version was known as the Cobra 25, with a crew of 3 men, 2 of whom were in the turret. The weight was still under 10 tons and mounted the 25mm Oerlikon KBB cannon (25 x 181) and a secondary 7.62mm machine gun in the turret along with an OIP/SCS-5 x 8 periscope each for the commander and gunner, a x8 night sight for the gunner and a x6 night sight for the commander. The cannon was able to be elevated to 60 degrees allowing this vehicle to double up in the air defence role as well. This very adaptable design too sadly received no orders.

tACEC Cobra 25 fitted with the Cockerill C25 turret
A final turret, the 2 man (gunner on the right and commander on the left) AK90E was designed by ACEC in around 1984 and was fitted with a 90mm MECAR/KENERGA main gun, capable of firing a full range of 90mm ammunition including APFSDS type rounds, and a secondary 7.62mm machine gun. It was also capable of fitting the Cockerill Mk.7 90mm gun.
The turret was intended to be available for other vehicles as it weighed just 2,600kg but never received any orders. Made from armour steel welded all around, the front could withstand armour piercing 7.62mm ammunition at 500 metres but the sides and rear were rated only for 7.62mm ball. The main armament could be elevated from -10 to +25 and the turret could complete a full rotation in about 28 seconds.
Marketed correctly as a ‘deadly threat to battle tanks’ ACEC had produced a very light, innovative and simple package ideally suited to the export market especially as it was under 10 tons in weight.

View of the ACEC Cobra 90 with rearranged hull and mounting 90mm Cockerill gun

ACEC AK90E electrical turret (smoke dischargers not fitted)
There were only a couple of other modifications to the ACEC Cobra 90 hull. The original driver’s hatch featured a single large front view port on the hatch which opened in a manner similar to the Soviet T-34 of WW2. This was modified later with additional side view ports on the hatch as can be seen on the surviving vehicle. This hull also had optional side skirts which could be removed too. The turret is sometimes seen with a large spot lamp which could be mounted on either side of the gun.

ACEC Cobra 90 showing early single viewport drivers hatch, the optional side skirts raised and no spot lamp on the turret.

ACEC Cobra 90, illustration by David Bocquelet

Photo credit: armyrecognition.com
Surviving ACEC Cobra 90, serial number 9601135 at the Depot of the Royal Museum of the Armed Forces, Kapellen, Belgium with gun removed.

Conclusion

The ACEC Cobra was a highly innovative vehicle, it just came at the wrong time. By the time it was ready for production there were already plenty of competitor designs for an AFV/APC and even light tank. The electrical drive system was probably off-putting for many mainly traditional buyers of arms unwilling to consider that it might be better than what they may have been used to. The Cold War ended not long afterwards too meaning a huge reduction in conventional forces in Western Europe and a glut of surplus equipment on the open market killed off what was a very promising line of development as the parent firm was sold off. With it died the prospect of a full range of variants based on this design such as the Cobra Command Post, Ambulance, Cobra Engineering vehicle, and Cobra Mortar Carrier fitted with a 120mm heavy mortar.
It is perhaps ironic that many of the features of the Cobra are once more being investigated to solve the same problems of reducing size and weight from rubber tracks to electric drive. Even the choice of the RCDU was ahead of its time with remote weapons stations common now.
The Cobra 90 tank is reported to have been shown at an international arms fair in Kuala Lumpur in about 1985 giving an indication as to the potential markets being sought but despite the advantages this design offered over its contemporaries it too failed to secure any orders. The Cobra tank prototype thankfully survives at the Belgian Tank Museum, Kapellen along with the APC versions, although the 90mm gun has been removed from the tank. The ACEC Cobra, be it the APC or the tank variant, might not originate from the most well known European tank making nation but the designs were well planned, well executed and well reviewed. Sometimes it doesn’t matter if you are better and cheaper than your competitors and the Cobra today is almost forgotten.

Sources

https://www.historyofwar.org/articles/weapons_acecCobra.html
https://cyberneticzoo.com/tag/belgian/
Janes Armour and Artillery 1985
Forges de Zeebrugge https://fz.be/
Cobra: der erste Schutzenpanzer der Welt mit elektrischer Kraftubertragungsanlage, P. Crevecoeur, 1980
Belgian Historical AFV Register V2.0, Michael van Loon, Neil Baumgardner, October 2012
Belgian Tank Museum https://www.belgian-tankmuseum.be
KBA/KBB 25 mm Cannon, Ordnance & Munitions Forecast, July 2002
International Defence Revue 4/88, 2/90

Cobra 25 specifications

Dimensions

4.77(hull), 5.30m(over gun) x 2.75m x 1.38m(hull), 1.95m(turret)

Total weight, battle ready

9,500kg

Crew

3 (driver, gunner, commander)

Propulsion

Cummins VT-190 V6 diesel 190hp

Suspension

Helical springs with hydraulic shock absorbers on wheel 1 and 5

Speed (road)

75-80 km/h (46.6 – 49.7 mph) / 5km/h (water)

Range

600 km (372.8 mi)

Armament

25mm Oerlikon KBB cannon with 250 rounds

Armor

All welded steel hull and turret providing protection 105mm HE shell bursts, small arms fire from NATO 7.62mm ball (at any angle or range) frontally proof against 7.62mm AP ammunition.

Total production

For information about abbreviations check the Lexical Index

Cobra 90 specifications

Dimensions

4.77(hull), 6.89m(over gun) x 2.75m x 1.38m(hull), 2.0m(turret)

Total weight, battle ready

9,500kg

Crew

3 (driver, gunner, commander)

Propulsion

Cummins VT-190 V6 diesel 190hp

Suspension

Helical springs with hydraulic shock absorbers on wheel 1 and 5

Speed (road)

75-80 km/h (46.6 – 49.7 mph) / 5km/h (water)

Range

600 km (372.8 mi)

Armament

90mm MECAR, 90mm Cockerill Mk.7 with 30 rounds

Armor

All welded steel hull and turret providing protection 105mm HE shell bursts, small arms fire from NATO 7.62mm ball (at any angle or range) frontally proof against 7.62mm AP ammunition.

Total production

For information about abbreviations check the Lexical Index

ACEC Cobra IFV

Kingdom of Belgium (1977-1990)
Infantry Fighting Vehicle – 4 Built

Belgium is not the first country to leap to mind for most people when they think of tanks or armored fighting vehicles, yet it has produced a few particularly interesting designs over the years. One of the these, which is virtually unknown, is the ACEC Cobra.
The Cobra is not a single vehicle but a platform, adaptable, lightweight and cost effective using diesel-electric drive to ensure the lowest possible weight and maximum space. The ACEC electric drive was one of the biggest selling points of the design allowing the Cobra into an exclusive club of diesel electric military vehicles.
The small and highly innovative Cobra was produced by the now defunct firm (acquired piece by piece by other companies until 1989) of Ateliers de Constructions Electriques de Charleroi ‘ACEC’. ACEC specialised in the manufacture of electrical motors including those for electric locomotives, and in 1970 ACEC did some work as part of the French Crotale surface to air missile program. As far back as 1967, ACEC had started work on electrical transmissions for tracked vehicles and, by 1970, had produced a version of the M24 Chaffee Light Tank fitted with an electrical transmission and an AMX 10P with one by 1978 too.

Direct Current motor reduction gear and brake assembly for the ACEC Cobra

The original Cummins diesel used on the ACEC Cobra producing 112 kW at 3300 rpm. Later versions increased output to 140 kW at 3300 rpm

After several years of study, ACEC determined that, rather than try and modify an existing vehicle to take an electrical transmission, it would be better to start from scratch with a whole new vehicle. As a result, in 1977, as a private venture, ACEC started working with the Belgian Army to create an APC with an electrical transmission, which would have allowed the new vehicle to be much lighter and more spacious than its contemporaries.
By the end of 1981, three prototypes had been completed by ACEC and finished their evaluation trials with the Belgian Army. A fourth vehicle with an improved engine was allegedly delivered for testing by 1985, but may simply be confused with the Cobra 90. Other trials were conducted in the USA by TACOM and the Department for Organization and Armament in Abu Dhabi, both of which found the handling and mobility to be very good.
The power from the engine in a conventional vehicle goes through a clutch and gearbox, through various reduction gearing and to the drive sprocket. For the Cobra, by using the power to drive just a generator, power could go directly to the gear reduction drives for each wheel instead, thus avoiding a lot of complex machinery, bulk, and more importantly, weight. Other advantages an electrical system offers over the traditional mechanical system are that it makes driving much simpler (no gear changes needed for example), steering is light and easy, thus reducing driver fatigue, and the maintenance of complex gear trains is eliminated.
Being lighter and using a generator system for power, the Cobra had a 600km range of action. Finally, the Cobra’s electrical transmission allowed it to accelerate faster than a mechanical transmission. The transmission also allowed the Cobra to accelerate and drive just as fast backwards as it did forwards.This is very useful for a reconnaissance vehicle, as it allows it to get out of trouble fast.

Early ACEC Cobra prototype hull, either P1 or P2, during fabrication. The spartan but rather spacious interior has two simple metal benches running lengthwise along each side. The driver’s stations can be seen at the front and are not closed off from the troop space. From inside, both front hull machine gun mounts can be seen and the arrangement of the drivers either side of the engine is clear. Two hatches (one circular and one rectangular) can be seen for the turret and additional crew egress respectively. Two smaller rectangular hatches are above the driver’s stations.

Dimensions

Weight was very important to the Cobra’s design. At only 7.5 tons (nominal), it was light enough to appeal as an export to many third world countries which lacked heavy infrastructure, as well as to Western forces, as a C-130 Hercules could carry three complete vehicles, making it easy to deploy. By the time of the fourth prototype, the combat weight was given as 8.5 tons, which still provided it with a power to weight ratio of over 20 hp per ton.

ACEC Cobra prototype number 3 during evaluation, note the full length track skirt and simple single machine gun mount on the central hatch. The tools are also stowed on a different location to later versions where they are on the sides.

Construction

The Cobra was manufactured as a welded all steel hull providing protection against all small arms fire including armor piercing ammunition.
Propulsion from the diesel engine was distributed by electrical motors to the rubber tracks driven by sprockets at the rear. The rubber belt track had steel links and rubber pads and the wheels were rubber tired meaning that the rolling noise of the Cobra was very low, due to the low engine noise, lack of transmission whine and lack of ‘squeaky’ track noise. The suspension consisted of helical springs with a hydraulic shock absorber on the first and last of the five wheel stations and four track return rollers.
The vehicle had a very large hatch in the back for the soldiers to enter/dismount with water-propulsion propellers either side of it. When entering water and engaging the propellers the front mounted trim vane automatically rose up on the front of the hull.

View of the rear of the Cobra showing rear door and the steerable propulsion propellers. Note the steering vanes not present on the earlier vehicles.
The APC version could seat up to 10 soldiers (5 each side). The crew (driver and co-driver) sat either side of the front mounted engine.

ACEC Cobra prototype number 4 with roof mounted heavy machine gun showing its trim vane in the raised position at the front and the large door and water propulsion propellers at the rear.

Engines

The first three prototypes (P1 to P3) were powered by a Cummins V-6 diesel engine producing 143 hp at 3300 rpm but P4 was fitted with a more powerful Cummins VT-190 supercharged diesel producing 190 hp at 3300 rpm. Another source states an 155 hp engine was used at one point. Water propulsion was supplied by means of two 3-blade propellers mounted at the back either side of the large rear door.

Various views of ACEC Cobra early prototype P1 or P2 lacking side skirts completely, no equipment on the sides, the folding trim vane and mounting twin anti-tank rockets. Note the 2nd visible machine gun port isn’t blanked off and that the mudflaps at the front appear to be simple rubber flaps rather than the hinged metal ones later.

ACEC Cobra prototype number 3 with a single machine-gun mounted on the cupola and initial set of sideskirts. Illustration by Tank Encyclopedia’s own David Bocquelet
Three surviving ACEC Cobra APC’s at the Depot of the Royal Museum of the Armed Forces, Kapellen, Belgium. Confusingly, the plain green painted vehicle appears to have another modification to the rear of the side, possibly connected to the hydrojet propulsion and removal of the propellers. The camouflage painted vehicle lacks this modification despite having a later registration number. 9601136 (plain green), 9601137 (sand), and 9601138 (camo) respectively. All vehicles display the later exhaust and muffler on the right hand side and the flat front ‘nose.’ This museum also holds serial number 9601135 which is the tank version. Photo credits:(left) armyrecognition.com, (center) Belgian Tank Museum, (right) army recognition.com.

Close up view of the ACEC lightweight (300kg) electric turret as fitted to the ACEC Cobra APC and mounting an FN 12.7mm M2HB heavy machine gun. Elevation range is -10 to +50. The searchlight moves with the gun as does the M20 x6 periscope. The turret is rated completely immune to 7.62mm ammunition at any angle or range as is the 10cm thick viewport. Space is provided in the back for a radio to be fitted.

ACEC Cobra APC during trials fitted with 12.7mm FN M2HB machine gun. It was at some point painted orange in perhaps a nod to the Dutch. Note the second machine gun hull mount is covered with spare track parts and that the ‘nose’ is the same profile as the rest of the glacis.

Armament

Standard fitting on the APC version was a single 12.7mm M2HB machine gun on the roof in a small turret fitted with vision blocks and two 3-barrel smoke dischargers (operated by one of the mounted soldiers) and a 7.62mm machine gun for the right hand side crew position fixed in a ball mount in the hull front. P4 was fitted with this weapon setup. A second hull machine gun mount in front of the other drivers station was also provided and is visible in some photos.
The RCDU ‘Remote Control Defence Unit’ was developed by Fabrique Nationale Herstal SA (FN) firm of Belgium and tested on one of the Cobra prototypes. It consisted of twin FN MAG 58 7.62mm machine guns (1500 rounds) weighing 258 kg or a single 12.7mm FN M2HB machine gun (600 rounds) weighing 300 kg in a remote station mounted on the roof capable of being operated by the crew who controlled it from below by means of a TV monitor. The RCDU could also be fitted with infra-red cameras and an additional compartment for more ammunition if required.

ACEC Cobra showing the twin 7.62mm RCDU in place and the second machine gun hull mounting position blanked off.
Other options for arming the Cobra APC was the use of the Oerlikon-Contraves GAD-AOA turret with model 204GK 20mm cannon, as well as the option for the Euromissile MILAN compact turret.

ACEC Cobra prototype hull with GAD-AOA turret and model 204GK 20mm cannon. Worthwhile noting here is the visible 2nd machine gun mounted in the hull front, the folding trim vane (as opposed to the automatic trim vane) and the raised ‘nose’ between the two drivers’ positions. For these reasons it is believed that this is one of the first prototype vehicles used as a demonstrator and these features are repeated on the vehicle used for the experimental RCDU and LAU-97.
A fire support version of the Cobra called LAU97 was tested in 1985 and was fitted with the FZ70 70mm rocket launcher with 40 rockets on a fully traversable mount on the roof of the vehicle. The FZ70 rocket was a product of Forges de Zeebrugge (FZ) now part of the Thales group and was an unguided rocket weighing approximately 4.3 kg and carrying 1 kg on high explosive intended for use against unarmored targets. The launcher however could also take a full range of 70mm rockets including anti-personnel, anti-tank, smoke, incendiary, illuminating, and flechette. It was able to fire them out to 8 km and designed for saturation of an area 200 x 300m.

Cobra LAU97 fitted with FZ 70 mm multiple rocket launcher, 1985. Note the precarious decision to have the rear hull top rectangular hatch open which, while ideal for reloading the launcher, would be suicidal to have open during launch.

Conclusion

The ACEC Cobra APC/IFV was small, maneuverable, and well designed. Cheap and simple to operate and train crews on it offered a capable platform for a wide variety of roles. For a relative newcomer to the military vehicle industry ACEC produced a remarkable vehicle which sadly did not receive any orders. With the end of the Cold War there was no market for a new vehicle, especially one challenges some of the preconceptions of the diesel-electric drive used and this the remaining vehicles. It wasn’t the end of the Cobra story, there was one final version of the vehicle, a light tank based on a redesigned hull.

Sources

Cobra AFV / APC specifications
Dimensions	4.52 x 2.75 x 1.76 m
Total weight, battle ready	8,600kg
Crew	2 + 10 (driver, co-driver, + up to 10 soldiers)
Propulsion	Cummins VT diesel 143hp (P1 to P3) / Cummins VT-190 V6 diesel 190hp
Suspension	Helical springs with hydraulic shock absorbers on wheel 1 and 5
Speed (road)	75-80 km/h (46.6 – 49.7 mph) / 5km/h (water)
Range	600 km (372.8 mi)
Armament	Single or double front hull 7.62mm FN MAG with; 7.62mm FN MAG on hatch ring / twin 7.62mm RCDU / single 12.7mm RCDU / 12.7mm ACEC turret / 20mm GAD-AOA turret / Euromissile MILAN compact turret (MCT) / FZ70 rocket launcher / 12.7mm with twin AT rocket launcher
Armor	All welded steel hull and turret providing protection 105mm HE shell bursts, small arms fire from NATO 7.62mm ball (at any angle or range) frontally proof against 7.62mm AP ammunition.
Total production	4
For information about abbreviations check the Lexical Index

ACEC Cobra Tank – Cobra 25 and 90

ACEC Cobra IFV

Kingdom of Belgium (1977-1990) Light Tank – 1 Built

From AFV to tank

Conclusion

Sources

Cobra 25 specifications

Cobra 90 specifications

Kingdom of Belgium (1977-1990) Infantry Fighting Vehicle – 4 Built

Dimensions

Construction

Engines

Armament

Conclusion

Sources

Cobra AFV / APC specifications

Kingdom of Belgium (1977-1990)
Light Tank – 1 Built

Kingdom of Belgium (1977-1990)
Infantry Fighting Vehicle – 4 Built