Envisioned by Engesa (a brazilian company known for it's military, civil veichles and also the initial widespread aplication of 4×4 chassis in Brazil and the invention of the boomerang suspension), it was a tank whose main purpose was to be a cost effective MBT while using domestically manufactured parts, with the intention of it being sold for the foreing market.
It was initially developed in 1982, with the first prototype complete in 1985, however, it caused a significant economical impact on the company, leading to heavier use of foreing parts on the construction of the tank, and higher loans given by the Brazilian government (wich at that time was an US-backed military dictatorship under operations Condor and Brother Sam)
Despite it's initial issues, it later participated in the saudi trials against the AMX, Challenger and M1 Abrams in 1987 and 1988, where it was nicknamed "Al-Fahd", managing to score very good performances, such as mobility & reliability, gunnery performance, fuel efficiency and transportability. However, armor was not part of their tests, but given Osório's lower weight and armor being able to sustain 105mm APFSDS, it may have been less armored than the M1 Abrams (wich was able to sustain 120mm APFDS and HEAT rounds at that time).
It's non adoption by either the Brazilian Army, Saudi Arabia and other countries who initially demonstrated interest led to the bankrupcy of Engesa in 1993, with the main reasons being political (Iraq invasion of Kwait in 1990 and the process of redemocratization in Brazil, with the second loosing some of it's interest on military projects on the country) and the widespread use of foreing parts.
Despite this, the EE-T1 and the EE-T2 MBTs are still consideried a hallmark in Latin America for it's performance and reliability, and also for it's computatorized aiming system developed by by then Marconi. There are currently 2 prototypes still in existence, with one being at display in the Military Museum Conde de Linhares (EE-T1), and the other resided at the Armored Instruction Center (EE-T2), both at Rio de Janeiro.
If I missed something or said something wrong, feel free to say.
by Afraid_Membership118