Specification Crew : 3 Engine power : 500 hp Combat weight :approx 14,000 kg (30,870 lb) Max speed : road 86 km/h (53.41 mph) Range : 250 km (155.25 miles) Length : 5.66 m (18.57 ft) Width : 2.29 M (7.51 ft) Height : 2.42 m (7.94 ft) Main gun : 45 mm (1.78 in) Armour : 6 mm (0.24 in) to 13 mm (0.51 in)

The BT-7 was a development of the BT-5 incorporating lessons learnt in the Khalin Gol battles against the Japanese.It retained the same automotive features but had an all-welded hull with sloping front plates to enhance protection a welded turret with sloping sides and a new track.The BT-5's limited used capability to travel on the road wheels rather then the tracks war removed. The BT-7 had several variants , including command tanks which by 1941 often had whip aerials in place of frame antennae.The OP-7 was a flame-thrower tank while the BT-7A was an artillery support variant with a short-barrelled 76.2 mm (3 in) howitzer in an enlarged turret.The final BT-8 (or BT-7M) version had a diesel engine and a machine gun to the back of the turret.Olny 706 BT-8s were produced compared to the 7,000 or so of all other BT models. BT-7s featured in the Red Army's advances into Poland in the wake of 1939 Germans invasion , and in Finland during the Winter War.But it was the German invasion of Russia in 1941 that saw the end of the BT series combat career.Shown to be under-gunned and under-armored especially against the Panzer III and Panzer IV it was phased out during 1942.