The BT-5 is a Light Tank and an early production variant of the Soviet BT (Bystrokhodny Tank) series, which used Christie suspension for high road speed. The BT-5 entered service in 1933 and saw combat in Spain, at Khalkhin Gol, and in the early phase of the Second World War. The 11.5 t tracked vehicle is crewed by three — driver, gunner, and loader — and reaches 51 km/h forward. The M-5-400 gasoline engine produces 400 hp for a 34.8 hp/t power-to-weight ratio.
Main armament is the 45mm 20-K with BR-240SP and BR-240, with a 3.77 s reload; a coaxial 7.62mm DT-28 is fitted. The gunner has 2.5x telescope and periscope sights and no stabilizer or rangefinder. The BT-5 was fast and mobile but lightly armored and later replaced by the T-34.
