KV-1The Soviet operational concept of 'Deep Battle', developed in the 1930's by, among others, Marshall Tuchachevsky, demanded for a heavy breakthrough tank. Such a tank should be heavily armed to withstand machinegun and artillery fire, had to be able to return heavy fire and had to posess excellent cross-country ability. The huge five turreted T35 tank, specially designed for this task, turned out not to be a succes. Armour and cross-country capabilty were seriously insufficient.
T35. Landschip
Experiences from the Spanish Civil War pointed to the importance of heavy armour. Based on these experiences, three new prototypes were developed, which were tested in the Finnish Winter War (1939-1940). The only single turreted type came out best and was further elaborated and taken into production. During 1940 it became operational under the name Kliment Viroshilov, abbreviated to KV.
KV model 1940, the first operational version.
The KV was a giant monster for its time, comparable in size and weight to the later German Panther and Tiger tanks. Its heavy armour was immune to all operational anti-tank guns, its 76mm gun could defeat all existing tanks on normal combat distances, and with its wide tracks this heavy tank could easily operate in deep snow, thick mud or marshy grounds. The firts German encounters with the KV were disconcerting. The German standard 37mm tank and anti-tank guns hardly scratched the KV tank. Only the 88mm anti-aircraft gun and daring infantrymen with magnetic hollow charges could destroy a KV tank.
Luckily for the Germans the early KV tanks were mechanically unreliable, difficult to operate and badly led. More tanks failed through mechanical trouble than by enemy fire. The Germans urgently started to re-equip their tanks with 50mm guns and replace their anti-tank guns by 50mm ones. The Soviets simply countered this by adding extra armour to the KV.
KV model 1941 with bolted on extra armour.
During 1942 it became clear to the Soviet high command that the KV tank had not much more to offer than the much cheaper and faster T34 tank. So after a last upgrade production of the KV was stopped in 1943 while development of a much heavier tank was started, resulting in the Josif Stalin series of heavy tanks.
KV model 1942, the last production model, hit in the turret, probably by an 88mm gun. This example has a cast turret. Other variants had welded turrets.