The T-100 was a twin-turreted Soviet heavy tank prototype, designed in 1938–39, which led to the development of the Kliment Voroshilov tank (KV-1). The T-100 was designed to be a super-heavy breakthrough tank by N. Barykov’s OKMO design team at S.M. Kirov Factory No. 185 in Leningrad.
The project was initiated by the Red Army’s need to replace the aging five-turreted T-35 tank based on combat experience in the Spanish Civil War. One of the lessons the Red Army drew from this conflict was the need for heavy ‘shell-proof’ armor on medium and heavy tanks. Although the T-35 was never used in Spain, its thin armor was vulnerable to the small towed antitank guns and gun-armed tanks encountered there by Soviet T-26 and BT tanks.
The T-100 was in direct competition against the very similar SMK heavy tank, by Lt-Col Zh. Kotin’s team at the Leningrad Kirovsky Factory. The original specification was for a five-turreted “anti-tank gun destroyer” which would resist 37mm guns at any range and 76.2mm guns at 1,200 m. Both design teams objected to the antiquated multi-turreted design, and the requirement was reduced to two turrets before serious design work began. Both tanks had some modern features, including thick, welded armor, radios, and torsion bar suspension.
The T-100 tank sported two turrets placed on a very long chassis. The front turret, mounting a 45mm antitank gun, was placed at a lower elevation than the other, thus giving the front turret a limited area of fire. The top turret, mounting a 76.2mm gun, was able to turn a full 360 degrees. The multi-turret design concept had been common in the 1930s, reaching its extreme with the British Vickers A1E1 Independent and the Soviets’ own derivative T-35.
Kotin received permission to enter a third design into the competition, the single-turreted KV tank, was much more modern, with a single large turret housing a dual-purpose gun.
The prototype T-100 tank was briefly tested in the Soviet invasion of Finland in 1939 without success. It was never put into production, due to the archaic design concept, poor mobility, and the availability of a far superior alternative, the KV series. It did lead to the SU-100Y self-propelled gun, which did not go into production, although the prototype was used in the defence of Moscow in 1941.