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The EE- T1 Osorio is a battle tank developed in 1980's the company Brazilian Engesa. Designed to compete with other prototypes built by the newly Bernardini the Tamoyo battle tank who excelled in everything.

that only two differences with the Tamoyo designed to operate in the Brazilian jungle and made especially for the financial and operational conditions Brazilian Army while Osorio was designed to be the first genuinely Brazilian MBT .

Shortly thereafter participated in a competition to equip Armed Forces of Saudi Arabia, The option for M1 Abrams prevented its production. Only prototypes were built.

Reasons for making

in the 80's the army of Saudi Arabia begun to study proposals for a new battle tank, to complement its arsenal, and in the futur

The sessions prototype Osorio painted with a camouflage scheme tested by the Brazilian army.

e replace the cars AMX -30, France. As the balance of forces in Middle East was always very gentle, the armies of those countries tend to be naturally militarily significant. In the case of Saudi Arabia, helped by its large exports of Oil, were able to buy good equipment.

The Saudi Arabia probably would buy Leopard 2, who were going into production for the army of the West Germany. This vehicle was considered reliable, and a generation ahead of Leopard currently used by the Brazilian Army .

However, the government of West Germany refused to sell the Leopard 2, claiming that he could not sell advanced weapons to countries outside the NATO. The Arabs did not know then how to get a vehicle considered last generation that could be delivered to them in large quantities. This sales opportunity was perceived by Engesa in Brazil.

Engesa ( Engineers Specialized S / A) was the largest maker of armored Latin America and was successful with two of its products, cars Rattlesnake and Urutu, Used by the Brazilian Army and exported, mainly to the Middle East, where he took part in the Iran-Iraq war . At that time the company experienced its best period . Given the opportunity, Engesa thought to provide the Saudis with a tank of Brazil.

However, and Engesa not yet developed any armored vehicle on tracks, and if the project, a MBT (Main Batlle Tank), They lacked experience. On top of his staff was busy with other projects, which would make it difficult to develop such a project, which would require almost all the company staff . So they decided to buy a project developed at another company and build it there, to show them to the Saudis . Then came a proposal from the German company Henschel - Tyssen, who had a project called Leopard 3 and who would be willing to trade it for the Brazilians. But the project was an infantry combat vehicle much like the Argentine TAM, away from the MBT concept . The Germans refused to sell anything other than Leopard 3, which became impossible to negotiate because the vehicle belonged to another niche, unable to compete with real MBTs as M1A1 Abrams American.

A second chance came again in Germany, as Porsche was interested in developing an MBT with the Brazilian company. Porsche possessed experience in this type of armor, and would be a form of Engesa acquire more experience in this matter. But again the partnership failed, this time by determination of the German government, which ordered that Porsche cancel the project.

Faced with the impasse of the major manufacturers of MBT, Engesa took decided to search directly from these manufacturers and suppliers, based on technology acquired there, develop the design itself MBT. That decision would cost the company's survival in the future.

Initial obstacles

One of the prototypes of EE-T1 Osório with the oficial Brazilian camouflages, only two prototypes were made, one with a 105mm cannon and one with a 120mm cannon

Develop projects independently would be more difficult than in the case of a partnership, as several obstacles would have to be implemented within and outside Brazil. The world was in Cold War and Bipolar, Representing antagonism of military equipment on the market : At the same time increasing sales of military equipment, also hindered the same trade, due to mistrust between countries.

Engesa still had to " please " the Brazilian Army. Interested in the project, it issued an BOO ( Basic Operational Objectives ), which would dictate the design of Osorio. A major problem was the limitation of this BOO weight of 36 tons in the house, unreal to the desired setting by Engesa for this project because other vehicles, potential bidders had weights between 44 and 65 tonnes. The weight given by the Army was not a MBT but a light tank . The Tamoyo III vehicle developed by Bernardini in parallel to Osorio stuck to BOO, and became a medium tank, not an MBT.

The Brazilian army does not actually looking for a MBT for two reasons: The first is the attribution of the Brazilian forces were essentially defensive, aimed at protecting the national territory. Brazil has practicing non-intervention and neutrality. In this kind of assignment, according to the generals of that time, it was not for an MBT, primarily offensive weapon . The other reason was simply the high cost of these machines. This applies to the cost per unit, and also the maintenance costs. A vehicle like Osorio, would obviously be expensive by the standards of the Army.

Yet Engesa managed to reduce the limitations that the Army gave to the project. Was set as the target for the number of weight 42 tons. The limitation would be kept wide (3.20 m). These limitations gave on behalf of the Brazilian railroads, used in transport tanks . Locked parameters, began developing the project.

At that time also set the name of the vehicle: Osorio. In tribute to General Osorio, patron of cavalry weapon of the Brazilian Army, who led the side Duque de Caxias the advancement of the Assumption, and the victory in Paraguayan War. In Saudi Arabia, would receive the name of Al Fahd, named after the then monarch of that country.

After that, Engesa sent engineers around the world to do research on what could be used in the design of EE-T1. They looked for equipment that would be used as engine, transmission (and etc. ].) . There were still other challenges, but the Brazilian Army was beginning to " get excited "with the project, and moved to support the company.

The project

The project that used high technology, was made with funds from Engesa own , without government assistance, although it would ruin the future. The engineers in their research trips found good equipment available. Most Europeans ( Americans did not sell military equipment "cutting edge "). So the engineers went to the Defence Components Exhibition in England. There he became interested in hydropneumatic Dunlop, who was being employed in MBT English Challenger 1. To use it, the original design would have to be changed, but the advantage was such that this suspension was chosen.

For transmission, we chose to ZF, LSG3000, because this company has facilities in Brazil, and that this transfer would be produced here, resulting in a reduction of costs. For the engine, was originally chosen the German MTU, used in Leopard 1 and 2, and the company wanting its manufacture in Brazil, but the cost was very high, so the company decided to use the TBD 234, 1000 Horses, also of German MWM. This engine had not yet been used in armor.

In the project design was used CAD technology to design the project with the aid of computers. This showed that the Engesa wanted to provide a vehicle of absolute quality, currently, these methods come to be considered banal.

In the requirement arms, the project was diverse: It was decided by two versions: The first, more sophisticated, it would take a 120 mm cannon GIAT (French), smooth soul . This would be exported to Saudi Arabia. A second, would use up to 105 mm cannon soul L7/M68 rayed . This would be the version of the Brazilian Army ( Cannon 105mm is standard in the West, so many countries produce ammunition, and its maintenance cost is lower). The chassis was the same for both versions, the differences

In this picture we can see the Osorio opening fire with his cannon of English L-7 105mm. Only the second prototype, is that it was armed with more powerful 120 mm cannon GIAT

were in the Tower (the 120mm had the best electronic equipment ). As secondary armament, a 7.62 mm machine gun Hughes, coaxial with the gun and the famous .50, serving as defense Antiaris . The Osorio had yet, at the top of the tower launchers, smoke grenades, which would form a smoke screen around the tank, preventing it from being seen.

For the shield, through tests, it was concluded that Osorio should make use of composite armor . used today. This was decided because it was expected that a bear shot straight Osorio 120mm ( because with this gun, it is assumed that his enemies would also ). So they went to Chobham, England get the technology of composite armor . They ended up hiring two engineers, who developed the composite armor in Brazil, together with a steel created by Usiminas. It has been speculated to use reactive armor ( reactive armor ) in Osorio, and despite never having been placed, it could be used. The Osorio had also angled forward enough, increasing the effect of shielding (at the top, the angle of the shield with the ground is nearly 0 ° ).

The Osorio tell even with the NBC protection (Nuclear, Biological, Chemical) Capable of giving protection to the garrison for many weapons. Such protection consisted of a total isolation of the cabin, creating an internal control. Among these devices, citing as an example the manual opening of the canyon, keeping had ammunition out of touch with the outside atmosphere.

The electronics was very advanced and the tank had a rangefinder laser (which measures the distance from the tank to the target, calculating the elevation of the cannon). An onboard computer of 16 bits was powered by such information, providing better conditions for shooting. Also had sensors for speed and intensity of wind, weather conditions, projectile velocity, among others. The gunner and commander displays had day and night, varying according to the version of the tower (105mm or 120mm) . The Osorio had stabilized the tower, and pay the gap, keeping the gun in the right direction of the target independent of the change of terrain. Associated with its "window of coincidence " for accuracy in the first shot was amazing 95%. The margin of error was just a circle with 50 cm radius.

Prototypes, testing and initial tests

Engesa stated the preparation of the first prototype for a year after the project began. To save time, they handed over the development of the towers Vickers, English, under the supervision of Brazilian engineers, while the chassis was developed on the premises of a subsidiary in Engesa Sao Jose dos Campos, São Paulo.

Simultaneously, tests were performed at screening CTA Technological Center ( Aerospace ), using a 25 mm cannon Swiss Engesa purchased by itself, tunnel reduced models of ballistic armor and increased speed of the missiles, thus mimicking the firing of guns of 105mm and 120mm.

The first chassis was completed before the tower in September 1984. Engesa then engaged him a false tower and submitted to tests of endurance, shooting and dynamic tests in order to repair defects in the set. Those that were discovered have been resolved, and the parameters of the hydropneumatic, agreed.

In May 1985 came the " standard tower " equipped with a 105mm rifled gun . She was immediately attached to the chassis and tested. In July of that year, Osorio went to Saudi Arabia aboard a 747 to its first tests in the desert. The intention was to send the prototype tower with 120mm (not yet finished) but the other competitors were already presenting their models and Engesa decided on taking the prototype had to analyze the performance of the chassis in the desert. There he met with the British Challenger who was also undergoing tests . The performance of the Osorio was positive, revealing weaknesses in particular engine, but failures were remedied. The team returned to Brazil happy with these tests.

The Army contributed, and CTEx (Technological Center of the Army) maintained a link with the team, keeping close to Engesa engineers, who instructed them mainly on maintenance. The factory has made changes to the engine driver who solved the problems presented in the desert. In this, the Brazilian Army initiated several tests with the prototype equipped with the Tower Pattern.

The tests were for elaboration of RTEx ( technical reports experimental ) and RTOPO ( Technical reports operational ) tests designed to assess what they needed in a vehicle. The prototypes were approved by the Brazilian Army after these tests, which were:

  • Shooting of 3269 km, 750 the arena Marambaia - RJ ( terrain ), and shot 50 rounds in total. The results thrilled the Brazilian military .

Early in 1986, Vickers delivered the second tower, with a 120mm cannon . He was immediately incorporated into the chassis and tested in RTEx and RTOPO . Like his predecessor had been approved with praise. It was now examining its performance in relation to its competitors.

Performance in the desert and initial success

In July 1987, the prototype with 120mm gun went to Saudi Arabia for the next phase of the competition. Now, the four vehicles would face in various tests. Vehicles were : The British Challenger, The American M1 Abrams, The French AMX-40 and the Brazilian EE-T1 Osorio.

The tests were to:

  • 2350 km of carriageway, being 1750 km in the desert. The garrison that would operate the tank was Army Arabia, chosen by lot. In this test also examine the fuel consumption should be limited to 2.1 km / l in desert and 3.4 km / l on the road.
  • Ramps : Overcome trench 3m wide, pulled out, leaving home at 65% ramp slope, turn on the ramp side slope 30%, acceleration and braking on the plane and on ramps .
  • Resistance and maintenance: Removing and putting caterpillars in 40 minutes (10 for removal, 30 for placement ), 6 hours with engine running constantly and stopped vehicle, 6 km from the march - and - aft towing a tank 35 ton per 15 km

    The first prototype of Osorio during a demonstration in the deserts of the Middle East. The Osorio is able to overcome obstacles up to 1.15 m high.

    Osorio The towed the Abrams, much heavier than 35 tons .
  • Shooting : 149 shots. 82 with the target vehicle and parked 4000m away, the other with vehicle stationary and moving target and moving target vehicle and the 1500m distance.

Disapproved the two European vehicles in the dispute (the Challenger and the AMX -40), and Osorio, along with Abrams were declared liable to purchase. Since, apparently what most impressed in testing out Osorio, being higher than the Abrams, and cheaper.

The Brazilian euphoria was enormous. The contract came to be prepared and is expected to be built including an assembly line in Saudi Arabia. Military Saudis came to Brazil to receive training in armored technology . The Brazilian Army was elated because the contract contained in the final price a 10% increase in the Brazilian Army (thus, the ten units sold to the Saudis would be delivered to a Brazilian army, paid by the Arabs ). The deal was the order of billions of dollars. Each unit 's serial Osorio would cost 1.2 million dollars.

In 1988 Abu Dhabi, the Osorio has made defeating the same opponents three plus the C-1 Ariete Italian, showing his skills . The only vehicle in its class against which the Osorio was not competed against the Russian tanks . As the cold war revenge, there were many Russian tanks to make comparisons.

To meet this future demand, Engesa planning to expand its fleet by about 1,200 square meters, increasing its machinery, to expand its staff by 500 or more employees, bringing jobs and technology exchange . The victory and sales to the Saudis were taken for granted, and a pre- series began to be built for export . Other markets were also probed : Iraq was interested in the vehicle, and even the Iraqi defense minister came to the country to know the car.

Political Intervention of the USA

Finally, United States acted, claiming that Brazil did not comply with international agreements and, above all, negotiating with nations regarded as enemies, have made Saudi Arabia hesitate to close the deal with Engesa . Hesitation that became declines with the onset of the Operation Desert Storm against Iraq in 1991, making the ties between the United States and Saudi Arabia is narrowed so that the Saudis decided to ignore the military capabilities demonstrated by EE T1 Osorio and sign the agreement with his main ally, the United States itself.

Given the nature of the work, obstacles encountered, and especially the risk of investing almost all its resources in a project aimed at foreign buyers, Engesa accumulated many debts. But this time, it was shown the true risks of the contract : the Brazilian government's unwillingness to invest in this business and the consequent lack of buyers for the EE T1 Osorio.

The unwillingness of the Brazilian government has shown itself mainly by small fields, both in policy in favor of the product, as much in financial aid on the plight of Engesa . The lack of money to acquire the Brazilian Army in the EE T1 Osorio was interpreted by the market as being, in fact, a lack of interest in the same product. Leading to the conclusion that not even the Brazilian Army buys the tank, then certainly other buyers would not buy it. Osorio 's first pre -series was sold as scrap metal, discarded their equipment ( guns, optronics, engine, transmission ...) for manufacturers to relieve the debts. Heritage was sold and went bankrupt in 1993 Engesa . It was the end of the line.

The prototypes built and survivors (Torre pattern and 120mm ) were in the custody of the Army, 13 RC Mec in Pirasssungua -SP but without belonging to it, so almost abandoned. These vehicles would be auctioned on November 20, 2002, however, prosecutors filed an action in São Paulo, preventing the sale of these vehicles. They would be sold for U.S. $300,000.00 the two units to a particular buyer, an amount irrelevant compared to the $50 million spent on its development.

Finally on March 22, 2003 There was an enthronement ceremony at the barracks of the 2nd CCR Pirassununga(Subsequently transformed into 13 RC Mec ), São Paulo, where the second prototype (P2 ) equipped with 120mm cannon paraded before the authorities, escorted by other vehicles of the regiment of cavalry . It was the " rebirth of Osorio . " The second prototype ( P1) with 105mm cannon is being restored, because the weather brought some defects to be repaired and it will also be incorporated into this regiment.

Today, both vehicles are owned by the Brazilian Army, being regarded as monuments to the memory and technology in Brazil. Until today, Osorio is the most advanced battle tank inventory of the Brazilian Army ( with single 120mm cannon ), and two generations ahead of the Leopard main battle tank currently in use in Brazil. In April 2003, he was exposed in 2003 LAD ( fair defense material ) in Rio de Janeiro. Struck several foreign delegations, even having been manufactured in the 80s . In 2003, approved a plan to reform the Brazilian Army Osorio, and is under review and a reformulation and possible production of MBT Osorio. The means of production are held by the Army, so the possibility exists.


  • Maximum speed: 70 km / h.
  • Maximum range: 550 km .
  • Engine: A motor MWM TBD 234 V - 12 with 1040 hp diesel-powered .
  • Weight: 42 tons.
  • Length: 10.1 m.
  • Width: 3.20 m
  • Height: 237 m.
  • Crew: 4I
  • Front tilt : 60
  • Lateral tilt : 40 º
  • Passing ford : 1.2 m
  • vertical obstacle: 1.15 m
  • Armament: GIAT cannon of 120 mm smooth-bore, a 7.62 mm coaxial machine gun and an M-2 machine gun of 12.7 mm anti -aircraft . 12 smoke launchers, 66 mm.

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