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EE-T1 Osório: The Lost MBT


The history of this tank is mixed up with the historical events going on in Brazil during the mid 1980´s. Brazil was experiencing a time of deep political changes, which marked the end of the dictatorship period and the beginning of the establishment of democracy by popular vote. In the military arena, Brazil already represented a great power in military equipment sales, mainly for Arabian countries. That equipment was, for the most part, armored fighting vehicles like the EE-9 Cascavel and personnel transport vehicles like the Urutu. Now at that time, the Saudi government was studying the possibility of replacing all its MBTs (main battle tanks). But they weren't entirely satisfied with what was available on the market. So, the ENGESA – (Engenheiros Especializados S/A), who was the maker of the Cascavel and Urutu (sold to mostly Arab countries) decided to invest in the development of an MBT that could satisfy both the demands of the Saudi government, and also offer the Brazilian government an MBT suitable to the unique conditions of the many environments found in Brazil. First, they decided to buy an existing foreign project. They discovered that Thyssen-Henschel of Germany, had a project designated Leopard 3, which was in reality an updated version of the TAM – Tanque Argentino Médio (Argentinean Medium Tank), which is a derivation of the Infantry Combat Vehicle (ICV) Marder. This vehicle would have little survivability against others vehicles like the Leopard 2, M1 Abrams, Challenger and others.

With the project launched, some basic requirements were addressed: The maximum width of 3,20m, maximum of 42 Ton, two main cannons (one version with the 120mm cannon and other with the 105mm (L7/M68)). It was named after Osório, in honor of the Brazilian Army Cavalry Patron. It was decided to have the hidropneumatic suspension of the Dunlop ( the same used on the Challenger), the transmission would be the ZF LSG3000 since the ZF has plants in Brazil. For the engine power, it was decided to use the diesel TBD 234 of 1000cv from MWM (Germany), even if that motor never been used in combat vehicles. The development started on the second half of the 1983 and the first prototype was ready in September, 1984. In May of 1985 it received the “Standard Turret” and the prototype was sent to Saudi Arabia. The vehicle wasn't entirely representative of the original plans, but against all advice the vehicle was shipped via airplane to Ryad on July 20, 1985, just after landing it already found one of its competitors in the trials, the British-made Challenger.

In this first test of the Osório, problems were found in the engine and they were rapidly solved by MWM when they returned to Brazil. Also at this time the Brazilian Army used one of the prototypes equipped with the 105mm cannon to do a complete process of RTEx (Experimental Technical Reports) and RTOp (Operational Technical Reports). In the beginning of the 1986 the Vickers delivered the second turret (with a 120mm cannon), it was incorporated right away to the chassis, as were all important lessons learned during the first tests in the desert sands and according with the RTEx and RTOp, in Brazil. Finally, in July of 1987, the final Osório Prototype, along with the best wishes and hopes of the ENGESA, went to a new phase of tests in Saudi Arabia. There its competitors were the Challenger, the AMX-40 and the M1 Abrams. All would be driven by Saudi military crews.

The test involved traversing 2350 km of road (1750 km in the desert), surpassing 3 meters width trenches, getting-away in a 65% slope, rolling over a 30% side slope, speeding, breaking, pivoting (180 degrees), fuel consumption (2.1 km per liter on desert and 3.4 km per liter in paved roads), track removal and installation (10 min. to remove and 20 min. to install), 6 hours with a running engine and stopped vehicle, 6 km in reverse gear and towing a combat vehicle of 35 Ton for 10 km, tests. During the shooting tests 149 shells were fired, 82 with vehicle and target parked (maximum range = 4000 meters); vehicle parked and moving target; moving vehicle and parked target; and moving vehicle and target (maximum range = 1500 meters). The engineering, technical and operational parts of Osório matched fully what was expected for it, and along with the M1 Abrams, it was declared passive to be bought by the Saudis. When the monumental billion-dollar business deal was about to happen, the real face of this situation was revealed. The political and economic power of the USA had determined the winner. The Saudi dynasty has always factored its survival in securing the continued support of Washington. This was clearly seen in 1991, with the Kuwait invasion by Saddam Hussein of Iraq. This marked the end of the ENGESA, and the Brazilian Army lost the opportunity to have a national vehicle comparable to the best in the world. Brazil is now an importer of used combat vehicles.

Project Photos

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About Paulo R Castro (ArmouredSprue)

I'm a 43 years old modeller originally from Brazil but now living in the beautiful Adelaide South Australia, and I like to build 1/35th military vehicles, both tanks and AFV and jeeps and trucks. I also enjoy building planes in 1/72, most WWII. Feel free to contact me by e-mail: armouredsprue@gmai...