On June 27th, 1931, the USSR started trials of an experimental medium tank designed by the German engineer Eduard Grotte.
E. Grotte was the head of a group of engineers from Germany that arrived in the USSR in March of 1930. The group was tasked with the development of a 20-ton tank armed with a 76 mm gun and a 37 mm gun, as well as machineguns. A special design bureau was created at the Bolshevik factory for this project, composed of the Germans and young Soviet engineers.
The result was the two-turreted medium TG-1 tank (Tank Grotte). For its time, the vehicle was very novel. It was the first domestic vehicle to have a fully welded turret and hull. The armour was sloped. The gearbox allowed same speed for moving forward and backward. The tank was controlled not with levers, but with a joystick, like a plane. Due to the pneumatic power steering, the driver's job was easier. The suspension was composed of five road wheels per side, 4 return rollers, an idler, and a rear drive wheel, and had a three layer shock absorber system for smooth driving.
The TG-1 has the most powerful tank gun for its time, the A-19 76.2 mm gun designed by Pavel Syachintov. A 37 mm PS-1 gun and five machineguns were used as auxiliary weapons. The armament was placed in three layers to ensure massed five in all directions.
With all its advantages, the Grotte tank never made it to production. All the novelties put into the design led to an unpalatable cost of production, and Soviet industry in the 1930s could not produce components of needed quality. As a result, the tank was unreliable.
Grotte left the USSR in 1933.
Thanks to the TG-1 project, valuable experience was gained, which was later used when designing domestic tanks. The famous Soviet tank engineer Nikolai Vsevolodovich Barykov started his career under Grotte's leadership.
Original article available here.