The Leichttraktor VK-31 was an experimental light tank used by Germany in the early 1930s. The Leichttraktor was later used as a training vehicle during the early years of World War II.
The Leichttraktor had a 100 hp, gasoline powered, six-cylinder Daimler-Benz M36 engine, which was capable of propelling it at speeds of up to 30 km/h. The hull and turret armor of the Leichttraktor was of riveted and welded construct, and by 1939, this armor design was obsolete. The crew requirement for the Leichttraktor was four, a driver, gunner, loader and commander. The armament of the Leichttraktor comprised of one 37 mm KwK L/45 gun and one coaxial 7.92 mm MG 13. The maximum operational range of the Leichttraktor was 137 kilometers.
Because the Leichttraktor had two manufacturers, the weight and dimensions varied. The models built by the Krupp steel works weighed 8.7 tonnes and measured 4.35 meters long, 2.37 meters wide and 2.35 meters high. The models built by Rheinmetall weighed 8.96 tonnes and measured 4.21 meters long, 2.26 meters wide and 2.27 meters high. The Krupp models were built on coil spring suspensions while the Rheinmetall models were built on leaf spring suspensions. No variants of the Leichttraktor were ever designed.
The Treaty of Versailles of 1919 prevented Germany from developing, producing or operating tanks, but in the mid 1920s the German government ordered the development of a series of armored fighting vehicles. These vehicles were primarily the heavier Panzer Neubaufahrzeug tanks, but a design for a lighter tank also emerged later in 1929. By 1930 three prototypes of these had been built, and codenamed the "Leichttraktor", or "Light Tractor". These vehicles were tested by the Germans in the Soviet Union under the Treaty of Rapallo of 1922, at the Kama Testing Grounds, which was currently a joint testing ground for the Red Army and the Reichswehr, and were designated the VK-31 prototypes. In 1933, a fourth Leichttraktor was produced. This was the last of the Leichttraktor VK-31s, which went on to influence the designs of later vehicles such as the Panzer I and Panzer II. The Leichttraktors were later used as training vehicles by the Wehrmacht.