Brazil’s wheeled viper
The Urutu, meaning “crossed pit viper” was a bit like the softer cousin of the Cascavel “Rattlesnake”. The Brazilian Engesa Company in 1970 was confident in its conversion/modernization program and launched a study for a combat wheeled APC, largely based on mechanical elements from the contemporary EE-9 Cascavel. One of its main feature was Engesa’s Boomerang double-axle rear drive suspension system. The base version was not protected NBC to cut costs down for exports, but the Brazilian Army adopted it, and the Brazilian Marines use to this day a tailored amphibious variant. Production stopped in 1987, details are not known, but over 1,500 appear to have produced.
At least some 800 Urutus have been exported to 20 countries, most prolific users being Iraq (200), and Libya (180) and the vehicle saw action in many theatres of operation for the past 40 years. The Urutu also has been developed into 9 variants so far. Although the Brazilian Army is known to operate 226 vehicles (as of 2010), many have been in storage for years before a modernization program came out.
Externally the Urutu shows an immediate link with the EE-9, with its 6×6 chassis. Indeed, the chassis is almost the same, but for modifications to carry a larger sloped hull. It’s not the prettiest vehicle around, but it is amazing to think the vehicle roots are in the American 1942 M8 Greyhound through the Cascavel. Development started in January 1970, at Engesa, S. José dos Campos (São Paulo) and the first prototype rolled out in July 1970. The idea was partly to “decline” the chassis into an AFV to ease export. Indeed, some customers that purchased the Cascavel, also had a go on the Urutu, having their maintenance costs down thanks to standardization.
Urutu’s double wishbone suspension being tested off-road
The same idea was behind the French Panhard AML/ M3 APC. Production officially started in 1974 and lasted for 13 years, the bulk of deliveries been exports (the last being to Colombia in 1992). The prototype was refined and made amphibious until eventually a production order was placed by the Brazilian Army which designated it vehicle “Carro de Transporte Sobre Rodas Anfibio” (CTRA), entering service in 1974.
First production vehicle in 1974.
This welded steel hull is wrapped around a 6×6 chassis, with a front right engine compartment. The latter had a distinctive front drive and rear Engesa Double Axle Boomerang Drive. The vehicle looks relatively stubby with a shot nose, barely sloped unlike many wheeled APCs seen today. However the upper nose part is well-sloped, with the added protection of the folded trim vane. As is, the vehicle is amphibious, but propulsion is assured by the means of wheels when swimming. This was seen as a vital asset for export, as well as the choice of a proven and available engine (see below). The driver’s front-left compartment was given three vision blocks with the optional swapping central IR block, and single-piece hatch. Behind is located the gunner, also given peripheral vision blocks (turret version). Access is allowed by a left side door, and a large rear hatch door for the exiting troops (operated by the driver), of which 11 are carried (plus the commander/gunner) seating on benches. They are given ten gun ports. Fuel jerrycans can be stored each side of the rear door on the back plate.
EE-11 ambulance version (credits Military today)
The slopped hull is made of 6 mm (0.28 in) overall and 12 mm (0.5 in) frontal arc, two-layer steel plating. The external layer is made of hard steel, while the internal armor features increased viscosity. Overall protection is assured small arms bullets, mine splinters and artillery fragments. The EE-11 Urutu was fitted with an automatic fire suppression system, but NBC protection system was optional. Many vehicles are also given smoke dischargers. It should be noted also a windscreen can be erected over the driver’s position.
The Urutu in a standard configuration possessed a single cal.50 (12.7 mm) machine gun, mounted on top of the roof. Variants are also fitted with various tailored turret-mounted armament (see options). The cal.50 can be protected either by a simple frontal shield, or an open turret (complete shielding).
Brazilian EE-11 with a cal.50 turret, modernized version.
As designed, the Urutu was given a Detroit diesel producing 158 hp, and the prototype was able to reach a top speed of 110 km/h on good terrain, even 80 km/h on off-road conditions. It also originally had a range of 750 kilometers before the upgrade (now 950 km). The Urutu is equipped with disc brakes and an automatic tyre inflation system. For amphibious operations, it is propelled at 8 km/h by two propellers with kort-nozzles and steered by two rudders at the rear. The diesel has a cooling system, comprising a water-to-air radiator for the engine water, oil coolers for the engine and transmission and transfer case oils. When swimming there is a keel cooler, while the air inlet and outlet louvres are closed (top, right of the driver).
Blueprint of the Urutu.
The Detroit 6V-53T is a 6-cylinder water-cooled diesel developing 260 hp at 2,800 rpm. It is coupled to an Allison automatic transmission with 4 forward and 1 reverse gears. The independent front suspension consists in a double-wishbone arms, coil springs and double-action hydraulic shock-absorbers. They are driven by hypoid angular transmission, plus bevel differential gears, and the axles can be pressurized for amphibious use. The rear suspension consists of semi-elliptical springs and double-action telescopic shock-absorbers, a trademark of Engesa. The EE-11 Urutu can negotiate gradient up to 60% and side slopes up to 30% and climb a vertical obstacle of 0.6m.
Tunisian EE-11 urutu Fire support variant.
Variants of the EE-11
Mortar Carrier: Armed with a M936 81mm/120 mm mortar, and also the crew of four.
Infantry Fighting Vehicle: This version is given a 25 mm cannon, coupled with an ATGM launcher.
Fire support variant: Large turret fitted with the Cockerill Mk.III 90 mm cannon, or in option the EC-90 (EE-9 Cascavel). 12 of these had been purchased by Tunisia according to photos and most sources.
Anti-aircraft Variant: Equipped with 20/25 mm autocannon.
Recovery Vehicle: Unarmed version given an hydraulic crane, and full maintenance kit/gear.
Anti-riot Variant: This version is given fences on all windows and smoke launchers.
Ambulance: Modified to carry four stretchers, full medical kit and personal.
Command Vehicle: This command vehicle is modified to monitor the battlefield, with two map tables, document storage, and full communications set.
Exports: Urutu around the world
Brazil alone is allegedly having 226 in service today. The list of registered operators includes Angola, Bolivia (24), Chile (37, no longer in service), Colombia (76), Cyprus (10), Dubai (60), Ecuador (18), Gabon (12), Guyana, Iraq (Formerly 200), Jordan (28), Libya (180), Nigeria, Paraguay (12), Suriname (15), Tunisia (18 12x 90 mm and 6 of the APC type), Uruguay (18), Venezuela (38), Zimbabwe (7).
Urutu of the Jordanian police, as of today
The EE-11 in action
Brazilian Urutus have been placed into storage with the end of the cold war, and according to Spanish sources, the Exército do Brasíl (army) operate(ed) 515 vehicles while the Infanteria de marinha do Brasíl (Marines) had 219 in service, and 226 has been modernized in the 1990s (engine and greabox in particular). This upgrade program was led by the Army’s São Paulo War Arsenal branch, as a stopgap until the arrival of the new VBTP-MR in 2012. Brazilian vehicles had been deployed with United Nations Stabilization Mission in Haiti (Brazil-UN).
Brazilian Urutu in UN colors, peacekeeping operation called United Nations Stabilisation Mission in Haiti from 2004.
The vehicle was well-proven in combat, and it’s certainly not over yet. It was bloodied in the Colombian civil war (1964–present) (Colombia), Chadian–Libyan conflict (Libya), Iran–Iraq War (Iraq), Invasion of Kuwait (Iraq), 1990-1991 Gulf War (Iraq), 2011 Libyan civil war (Pro-Gaddafi forces and Anti-Gaddafi forces) and Iraq Civil War (2014–present).
EE-11 Urutu specifications (1974)
|Dimensions||6.1 x 2.6 x 2.9 m (20′ x 8’5” x 9’5” ft)|
|Total weight, battle ready||14 tons|
|Crew||1+12 (driver, 12-14 soldiers)|
|Propulsion||Detroit Diesel 6V-53T 260 hp|
|Suspension||6×6 independent coil springs|
|Speed (road)||105 km/h (61 mph) 8 kph swimming|
|Range||320 km (200 mi)|
|Armament||APC: Cal.50 12.7 mm browning M1920 HMG. See notes|
|Armor||8 mm sides to 14 mm front (0.3-0.4 in)|
|Total production||1,500 in 1974-1985|
Early Brazilian Engesa EE-11 Urutu APC, 1970s
EE-11 late APC, Brazilian Marines
Urutu (late) of the Brazilian Army
Urutu in UN livery, United Nations Stabilisation Mission in Haiti
EE-11 Cockerill MkIII 90 mm
EE-11 Urutu Armored Recovery Vehicle
Export livery Engesa EE-11 APC
Tunisian fire support vehicle Cockerill 90mm turret
Urutu used by the Peshmergas, Northern Iraq
Bolivian EE-11 IFV, with a 20mm autocannon
Bolivian EE-11 IFV
EE-17 Sucuri Tank Hunter, based on a modified, elongated chassis.