Tank T-17 (1929)
Weight: 2.4 Tons Crew: 1 man. Armament: 1 machine gun, 7.62mm. Armor: 14-10mm Speed: 16 km/h.
Production of the T-18 was bottlenecked because of a severe lack of engines. I theorise that the T-17 was an attempt at making a tank that could be produced en masse much easier than the T-18, using a much more available engine, eliminating the turret, etc. By choosing the 2 Cylinder air-cooled engine, performance would have been greatly reduced if the vehicle weighed the same as the T-18.
Presumably, they wanted the T-17 to be able to operate in unison with the T-18. To do so with an inferior engine, weight was dropped from 5.4 Tons to 2.4 Tons, the drastic decrease in size necessitating it being only a one-man tank. In this way, the far less powerful engine could get the T-17 up to within 1 km/h of the T-18. (17kmh Vs. 16kmh for the T-17).
As with all Tankette development, the reason was not sound combat logic, it was pure economic logic.
Some information sources tells that only one T-17 was ever built. Others say around 3 were built, that the first one had metal tracks, but the second two had rubber & metal tracks.