The Brazilian EE-T1/T2 Osório Main Battle Tank was Brazils attempt at indigenous and self-reliant MBT production by the Brazilian company, Engesa who had had some success in production since it’s entrance into the arms industry in 1963. It had completed various projects, mostly working on retrofitting old military Brazilian equipment and eventually moving on to developing armoured vehicles for both indigenous use and importantly export to the Middle East and North Africa.
In 1982 development began in a new venture by Engesa into MBT production for its current export clients, who were having trouble purchasing newer MBT’s built in member country’s of NATO (The Leopard 2) as they were non NATO members.
Original requirements by the Brazilian Army were that the tank could not exceed 36 tons and could not be wider than 3.20m due to limitations of the Brazilian public transportation network. Engesa stuck with the width limitations but not the weight, fearing it would not be in the same class as NATO MBT’s at the time. Wanting to maximise on variants they could sell, Engesa wanted more than one type of turret, to reflect on the current change at the time, moving from the traditional highly successful L7 series 105mm rifled Royal Ordnance , to the newer 120mm smoothbore cannons. So two turrets were to be built, one housing the 105 mm L/52 L7 cannon and storage for 45 rounds, and another housing the 120 mm GIAT G1 French smoothbore cannon and storage for 40 rounds.
There had been some interest by other arms manufacturers in Europe to help in its development, but were restricted by agreements with Germany. So Engesa concentrated on the development of the hull, whilst British firm Vickers Defence Systems concentrated on the development of both turrets and by 1985, the first prototype was completed.
It was fitted with a modern Marconi fire control computer & laser range finder. The power pack was a MWM TBD 234 turbo charged diesel engine producing 1000 hp. It also had a ZF produced LSG 3000 transmission and Dunlop produced hydro pneumatic suspension, giving the vehicle a top road speed of 70 km/h, an operational range of 550 km and a fuel capacity of 1354 litres.
The Osório’s survivability concentrated on firepower & speed. Its armour was composite and developed by Engesa and included aluminium/steel, carbon fibres, and ceramics, keeping the tanks weight down to 39000kg (39 tons).
In order to keep production costs down for Osório’s manufactured for the Brazilian Army, Engesa looked at exporting it first, as the Brazilian Army had a small budget and could not financial contribute to the development costs. A number of Middle-East countries were interested in the Osório, especially Saudi-Arabia who had completed successful field trials prior to the Gulf War and had given the go ahead saying they were going to buy over 300 of them. But the Gulf War broke out in 1991 and after not signing the contract in the mid-80’s, Saudi-Arabia went with the M1-A1 Abram’s.
Foolishly Engesa had spent over $100 million in the Osório’s development after it passing field testing with Saudi-Arabia, but not getting the signature on the order sheet. In 1993 Engesa filed for bankruptcy and sadly the Osório never saw production. The Brazilian Army still uses 132 of its original 334 Leopard 1 A5’s and also 91 US M60-A3’s.