The Soviet army of World War II was not short of fast cavalry tanks. The BT-7 was built in the thousands and used in early battles against the Japanese and later the invading Germans. Capable of an impressive 44mph on roads and over 30mph across country, it weighed in at over thirteen tonnes and used its speed for protection rather than it's light 20mm thick armour. The BT-7 had a crew of three – the driver, loader, and commander, who also served as the gunner, were kept busy serving a 45mm…