Main Battle Tank EE-T1 "Osorio" (Brazil)

Modification EE-T1 EE-T2
Entered service in 1988 -
Crew 4
Dimensions and weight
Total weight in combat order 41 t ~ 43 t
Overall length ? 10 100 mm
Chassis length 7 130 mm
Overall width 3 200 mm
Overall height 2 370 mm
Armament
Main gun 105-mm rifled gun L7A3 120-mm smoothbore gun
Machine guns 2 x 7.62-mm 1 x 7.62-mm, 1 x 12.7-mm
Traverse range 360 degrees
Combat load
Main gun 45 rounds 38 rounds
Machine guns 5 000 cartridges
Mobility
Engine power 1 040 h.p.
Maximum road speed 70 km/h
Autonomy on roads 500 km 550 km
Maneuverability
Slope 30°
Vertical step 1.15 m
Ditch 3 m
Ford (unprepared) 1.2 m



The EE-T1 "Osorio" Main Battle Tank was developed in the middle of 80-ties by "Engensa" - the largest Brazilian weapon developer. Companies technical politics is based on a wide usage of other companies providing military technologies scientific strides. Furthermore if some component production license price is too high, "Engensa" usually buys already produced and completes it's products with such, or offers job for specialists who took part designing one or another product. In this way "Engensa" resolves two main problems: it's production is at a high technology level and it's price is suitable even for a third world countries.

Hull and turret are differentially armored. Rear part is armored with a multi-layer armor which is made with included composite materials and is similar to British "Chobhem" armor. Frontal armor plates are placed with a high inclination level providing better defense.

"Osorio" armament is placed in three-seat turret. As well as EE-T1 is intended not only for Brazilian armored forces, but for export as well, it is produced with two armament variants. EE-T1 intended for Brazilian armored forces is armed with British L7A3 105-mm rifled gun, while export modification EE-T2 is fitted with French 120-mm smoothbore gun. It can be also completed with Soviet/Russian 2A46 125-mm smoothbore gun.

105-mm main gun combat load consists from 45 projectiles including armor-piercing and high-explosion with plastic explosives. Additional armament consists from 7.62-mm machine-gun, coaxially mounted with a main gun, one more 7.62-mm anti-aircraft machine gun is placed placed on the roof in front of gunner's hatch. "Osorio" can be completed with 12.7-mm anti-aircraft machine gun placed in front of the commander's hatch.

Main gun is stabilized in two planes. It's aiming and turret rotation devices are based on electricity. "Osorio" Main Battle Tank is fitted with Belgium commander's SCS-5 and gunner's LRS-5 sights. LRS-5 is combined periscope type sight. It combines optical sight with day and thermo vision night channels, also laser rangefinder and ballistic computer. Commander's sight differs from gunners in absence of laser rangefinder and ballistic computer. It is placed in commanders turret and connected with a main gun. Commander is able to aim and to fire independently from gunner. Tank's commander use 5 periscopes for 360 degree observation.

In 1987 "Engensa" finished EE-T1 export modification's - the EE-T2 Main Battle Tank's tests. The new main battle tank was intended only for export, mostly to the Near and Middle East countries. This modification was not used in Brazilian armored forces. The main difference is that the EE-T2 features 120-mm smoothbore gun instead of 105-mm placed on EE-T1 and improved fire control system.

EE-T2 "Osorio's" 120-mm gun ammunition load consists from 38 projectiles with two type rounds: armor-piercing and multifunction projectile (high-explosion fragmentation). It's fire controll system contains WS 580-10 commander panoramic sight and WS 580-19 gunners periscope sight. Sights are designed by French company "Sfim". Both sights are made with built-in laser rangefinders connected with ballistic computers. Sights viewing range has independent stabilization. One more "Philips" UA-9090 night vision panoramic thermal sight is mounted on the turret. It's view is projected on television screens, placed in front of gunner and commander. "Osorio" EE-T2 has a hit probability into moving target in 2 000 meter range from the first round in more than 80%. Such results were published by French specialists.

EE-T2 secondary armament consists from 7.62-mm coaxial and 12.7-mm anti-aircraft machine guns. Like the EE-T1 it is also fitted with a smoke grenade launchers, placed from both sides of the turret.

Both Main Battle Tanks have the same engine and transmission built in one module. Engines are German 12-cylinder MWM TBD 234 diesels with ZF LSG 3000 transmissions. Engine block is replaced in 30 minutes in field conditions.

Chassis includes 6 bearing and 3 supporting rolls from the each side. Tracks are similar to the "Leopard 2" Main Battle Tank's ones with removable rubber pads. Chassis suspension is hydro pneumatic. First, second and sixth bearing rolls are fitted with spring absorbers. Hull boards and chassis is covered with armored screens providing additional protection from cumulative rounds.

"Osorio" has a good speed and cross-country performance. It reaches 30 km/h in 10 seconds. Main Battle Tank manages 30º slopes, 3 meter wide trenches, 1.15 meter vertical step. It fords 1.2 meter depth water obstacles without preparation.

The Main battle tank is completed with an automatic fire-extinguishing system in combat and engine-transmission compartments. "Osorio" can be additionally fitted with Nuclear Biological Chemical protection system. This system includes air filter and individual masks for crew members, providing cleaned air. There is also ability to place special device signalizing when main battle tank is lightened by a laser beam. It is also fitted with all necessary radio equipment and crew communication devices.

Later on the "Osorio" Main Battle Tank chassis there were based such armored vehicles:

- Self-propelled howitzer fitted with GHN-45 155-mm howitzer;

- Anti-aircraft defense vehicle with coaxial "Oerlicon" automatic guns;

- Armored engineering vehicle;

- Tank - bridge-layer.

There is no information about the "Osorio" EE-T2 serial production, however countries such as Saudi Arabia showed interest to obtain it for their armored forces. Brazilian requirements in EE-T1 is approximately 300 main battle tanks.