During the 1920s and 1930s the tankette was a continuing attraction for the military mind and the tank designer, and the Soviet Union was no exception in this trend. By the late 1930s the Red Army had progressed through the stages where the one-man tankette had been tested and dropped and was in the usual stage where the tankette had developed into the two-man light tank. By the time the Germans attacked in 1940 the Red Army had invested fairly heavily in the light tank, and the models in service were the result of many years of development. One of the main types in 1940 was the T-40 amphibious light tank, armed with a 12.7-mm (0.5-in) machine-gun. It was the latest in a long line of models that could be traced back to the T-27 of the early 1930s.
This had progressed through the T-33, the T-34 (not to be confused with the T-34 medium tank), the T-36, the T-37 and finally the T-38. Most of these lacked the amphibious capabilities of the T-40 which was placed in production in about 1940, so that by the time the invasion of 1941 started only a few (about 230) were ever completed. Many of the lateproduction T-40 models (with streamlined nose and foldable trim vane) were converted into Katyusha rocketlauncher carriers and were never used as turreted tanks, whose normal armament was one 12.7-mm (0.5-in) and one 7.62-mm (0,3-m) machine-gun. Armour ranged from 6 to 13 mm (0.24 to 0.51 in) in thickness.
While the amphibious T-40 was being developed a non-amphibious version, known as the T-40S, was proposed. When the Germans invaded, the call was for many more tanks delivered as rapidly as possible, so the simpler T-40S was rushed into production and redesignated the T-60 light tank, Unfortunately it was a bit of a horror in service and carried over the primary bad points of the T-40: it was too lightly armoured and, having only a 20-mm cannon plus a co-axial 7.62-mm (0.3-in) machine-gun as armament, was useless against other tanks. Also it was so underpowered that it could not keep up with the heavier T-34 tanks across country. T-60s were kept in production simply because they could be churned out quickly from relatively small and simple factories. They were powered by truck engines, many components being taken from the same source, and the slightly improved T60A appeared in 1942 with slightly thicker frontal armour (35 mm/1.38 in instead of 25 mm/0.98 in) and solid instead of spoked wheels.
By late 1941 work was already under way on the T-60's successor. This was the T-70, whose first version used a twin-engine power train that could never have worked successfully in action and which was soon replaced by a revised arrangement. The T-70 was otherwise a considerable improvement over the T-40 and T-60. It had heavier armour (proof against 37-mnV 1.46-in anti-tank guns) and the turret mounted a 45-mm (1.77-m) gun and 7.62-mm (0.3-in) machine-gun. This was still only of limited use against heavier tanks but was better than a mere machine-gun, The crew remained at two men, the commander having to act as his own gunner and loader in a fashion hardly conducive to effective operation of tank or units.
Production of the T-70 and thickerarmour T-70A ceased in October 1943, by which time 8,226 had been produced. In service the type proved remarkably unremarkable, and the vehicles appear to have been confined to the close support of infantry units and some limited reconnaissance tasks. By 1943 the light tank was an anachronism, but the Soviets nonetheless went ahead with a replacement known as the T-80. Almost as soon as it went into production its true lack of value was finally realized and the production line was switched to manufacturing components for the SU-76 self-propelled gun.
Specification T-40 Crew: 2 Weight: 5.9 tonnes Powerplant: one GAZ-202 petrol engine delivering 52 kW (70 hp) Dimensions: length 4.11 m (13 ft 5.9 in); width 2.33 m (7 ft 7.7 in); height 1.95 m (6 ft 4.8 in) Performance: maximum road speed 44 km/h (27.3 mph); road range 360 km (223.7 miles); fording amphibious; gradient 34°; vertical obstacle 0.70 m (2 ft 3.75 in); trench 1.85 m (6 ft 1 in)
Specification T-60 Crew: 2 Weight: 6.4 tonnes Powerplant: one GAZ-203 petrol engine delivering 63 kW (85 hp) Dimensions:Iength4.11 m(13 ft 5.9 in); width 2.3 m (7 ft 6.5 in); height 1.74 m (5 ft 8.5 in) Performance: maximum road speed 45 km/h (28 mph); road range 450 km (280 miles); fording not known; gradient 29°; vertical obstacle 0.54 m (1 ft 9.3 in); trench 1.85 m (6 ft 1 in)
Specification T-70 Crew: 2 Weight: 9.2 tonnes Powerplant: two GAZ-202 petrol engines delivering a total of 104 k W (140hp) Dimensions: length 4.29 m (14 ft 0.9 in); width 2.32 m (7 ft 7.3 in); height 2.04 m (6 ft 8.3 in) Performance: maximum road speed 45 km/h (28 mph); road range 360 km (223.7 miles); fording not known; gradient 34°; vertical obstacle 0.70 m (2 ft3,6 in); trenchS. 12 m(10 ft2.8 in)