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MB-3 Tamoyo

Prototype main battle tank

MB-3 Tamoyo

The Brazilian MB-3 Tamoyo was an interesting MBT project, however it received no production orders

Tamoyo II
Entered service -
Crew 4 men
Dimensions and weight
Weight 30 t
Length (gun forward) 8.76 m
Hull length 6.5 m
Width 3.22 m
Height 2.48 m
Main gun 90-mm rifled
Machine guns 1 x 12.7-mm, 1 x 7.62-mm
Elevation range - 6 to + 18 degrees
Traverse range 360 degrees
Ammunition load
Main gun 68 rounds
Machine guns 600 x 12.7, 3 000 x 7.62
Engine Saab-Scania DSI-14 diesel
Engine power 500 hp
Maximum road speed 70 km/h
Range 550 km
Gradient 60%
Side slope 30%
Vertical step 0.7 m
Trench 2.4 m
Fording 1.3 m
Fording (with preparation) ?


   The Bernardini MB-3 Tamoyo was the product of one of the most unlikely tank projects in history - an attempt to develop a main battle tank out of the chassis of a light tank. It was essentially an offshoot of Bernardini's earlier 1970s modernization of Brazil's M41 Walker Bulldog light tank fleet to the M41C Caxias standard. Apparently, Bernardini felt that they could take the project much further than the upgrades specified by the Brazilian government, and decided to develop an M41-based tank that was much better-suited to a 1980s battlefield.

   First designated "X-30", the program was established in 1978. The first MB-3 Tamoyo prototype was completed in 1982, and was armed only with a 76-mm gun, but the following 9 prototypes built in 1983 through 1985 had 90-mm guns (the 11th and last prototype had a 105-mm gun). The hull was significantly redesigned over the M41, and the turret was essentially all-new, resulting in a tank that looked almost nothing like what it was derived from.

   Though the Brazilian government was highly impressed by the Tamoyo, and performed trials of it throughout the 1980s, as did Paraguay and Peru. It is worth mentioning that soon after another Brazilian MBT - the EE-T1 Osorio, developed by Engesa, has been introduced. However, the sudden onrush of cheap, second-hand tanks starting in the late 1980s (some of which were literally given away, at shipment cost only) ultimately doomed this venture. With the option to purchase hundreds of M60A3 TTS main battle tanks (and Leopard 1A5s soon after), the Tamoyo didn't stand a chance. Bernardini continued its marketing campaign for M41 conversions into MB-3 Tamoyo into at least 1993, but ultimately no buyers came forward, and the project was abandoned.

   Compared to the M41 it was derived from, the chassis of the Tamoyo is unrecognizable without a close inspection. It has been stretched by several feet, a additional roadwheel has been added, different armor arrays, a cluster of smoke mortars, a new wedge-shaped gun shield, a track skirt (from the aforementioned M41C Caxias), a new and longer gun, and a longer, raised rear engine deck. The turret was completely original, and significantly lower, more angular, and more shallowly-sloped than the original example from the M41.

   The Tamoyo is 8.76 m long, 3.22 m wide, 2.48 m high, and has 0.5 m of ground clearance. It can surmount a 0.7 m vertical step, ford a 1.3 m deep water obstacle, and tackle a 60% gradient and 30% side slope.

   The suspension utilizes the standard torsion bars of the M41 light tank, but has 12 instead of the usual 10 (due to the added 6th pair of roadwheels). The 6 roadwheels, 3 return rollers, drive sprocket, and idler are the same as used in the M41 Walker Bulldog, and the track seems to be the same T91E3 from the M41 as well. The first, second, and sixth roadwheels are fitted with hydraulic shock absorbers. The ground pressure is approximately 0.72 kg/cm2.

   Propulsion is provided by either of two different V8 diesel engines; a 500 hp Saab-Scandia DSI-14, or a 730 hp Detroit Diesel 8V-92TA. The available gearboxes are a General Dynamics HMPT-500 automatic transmission, with 3 forward and 1 reverse speed (for the DSI-14), and an Allison CD-500-3 automatic transmission, with 1 forward and 1 reverse gear (for the 8V-92TA). With the Saab-Scandia engine, the Tamoyo has a power/weight ratio of 17.18 hp/t; with the Detroit Diesel engine, itís power/weight ratio is 25 hp/t. Both transmissions allow a pivot-steer capability, which the original M41 Walker lacked.

   At least 4 different main guns are available for the Tamoyo - the original M32 rifled 76-mm gun of the M41; Bernardiniís own 76/40 M32 BR3, a rifled 76-mm gun with a tube 40 calibers long; the Bernardini rifled 90-mm gun, 40 calibers long (with 68 rounds); and the L7A3 rifled 105-mm gun (with 40 rounds), with a tube 52 calibers long. The Tamoyo also has a coaxial machine gun and an anti-aircraft machine gun on the roof, either or both of which may be a 12.7mm M2HB, or a 7.62mm MAG. Both the main gun and coaxial gun are fully stabilized on 2 planes, allowing the Tamoyo to accurately fire on-the-move, even at high speeds.

   The Tamoyo has vision blocks and/or periscopes for all 4 crewmen, day/night sights for both the tank commander and gunner, and both GPS (Gunner's Primary Sights) and GAS (Gunner's Auxiliary Sights) for the gunner. The definitive fire control system of the MB-3 Tamoyo is the Ferranti Falcon, which includes a digital ballistics computer, and a laser rangefinder.

   As with most AFVs of its era, the exact qualities of the Tamoyo's protection are classified, but it is known that it has composite and spaced armor, and generous track skirts. Known crew protection features include an automatic carbon dioxide fire suppression system, a belly escape hatch, and a sealed ammunition compartment, and an optional collective NBC protection system.

   The offered price for an MB-3 Tamoyo varied, depending on the customer's preferred configuration, and could cost up to $2.8 Million.




   First prototype; armed with a 76-mm gun;

   MB-3 Tamoyo; the second prototype, armed with a 90-mm gun;

   MB-3 Tamoyo II; a later variation of the second prototype, also armed with a 90-mm gun;

   MB-3 Tamoyo III; the 11th and final prototype, armed with an L7A3 105-mm gun;

   Self-Propelled AA Gun; proposed variant armed with twin Bofors 40mm L/70 autocannons.



   Article by BLACKTAIL

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Video of the MB-3 Tamoyo prototype main battle tank

MB-3 Tamoyo

MB-3 Tamoyo

MB-3 Tamoyo

MB-3 Tamoyo

MB-3 Tamoyo

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