Soviet Heavy Tank KV-1 (Klim Voroshilov - 1)

"A small column of hitler's tanks was seen ahead. There were seven of them. Grigorjev drove his tank to the advantageous position and after the Shabunin's order Stupin opened fire. He burned the enemy tank with the first hit. The second one was enveloped by smoke. It stopped. But the third one was closing fast. Suddenly the strong hit shattered the Grigorjev's machine. Tank was unable to shoot any longer. Through the watching hole Grigorjev saw, that the closing fascist tank began to turn gun barrel to the damaged KV. Two anti-tank guns were taking their positions to the right. Of course, there was a chance to flee. But that meant to open the way for the enemy.
- I'm going to taran! - shouted Grigorjev, as he throwed his tank forward.
- Do it, - Shabunin answered.
An enemy shell bounced off the tank's armour. Grigorjev's tank was charging forward. After a while, it collided by all its 50 tons with an enemy machine and overturned it." - 32nd tank brigade during Moscow counterattack, December of 1941 as it was described. During the war, driver Grigorjev became Hero of the Soviet Union. It was one of the first tarans (planned collisions made by own vehicle with an enemy one) made by a tank during the battle under Moscow.
During the Soviet-Finnish conflict, 2 KV tanks went to front straightly from the factories. 17th December they have proved their qualities in battle. Their main strengths were thick armour and strong firepower. The mass production of KV-1 began during the summer of 1940.
At the beginning of 1941 tank KV-1 was modernizated. It had more powerful 76.2mm/41.5 gun and increased its front hull armour to 105mm. The weight also increased a lot. It received a cast turret of 7 ton. The cast turret of such weight was a technological progress at these times. During the 1940 factories made 243 and during the first half of 1941 - 393 tanks KV-1 and KV-2. KV-1 was superior than T-34 in armour, had the same armament and was inferior in speed and mobility. Its superiority on German tanks was even higher than its of T-34. Soviet authors say that no one German tank or anti-tank gun was able to pierce armour of KV. The facts tell us, that German 88mm Flak cannon could.
At the beginning of Great Patriotic War (22th June, 1941) Kirovskij factory was transferred to Cheljabinsk and was renamed to Cheljabinskij Kirovskij zavod. Nevertheless during the second half of 1941 front received 933 KV tanks.
During the battles the need of better mobility and some better details was found. During the second half of 1942 tank was modernizated by N.F.Shashmurin. New model, called KV-1S ("S" meant "skorostnoj" - "speedy") had the weight of 42.5 ton. The lesser weight cost the decrease of armour and the length of hull. Motor section was also modernizated. Commander's cupol was installed. Speed increased up to 42km/h. KV-1S was producted for the one year. During the same time, KV-8 tank was produced. It had the flamethrower and a 45mm gun.

Soviet Heavy Tank KV-2 (Klim Voroshilov - 2)

During the summer of 1940 some of KV-2 tanks with the 152mm howitzer were made. The gun was installed in a quiet bulky turret, the height of the model increased up to 3.25m. Tanks KV-2 were self-propelled artillery after all. They could shoot while not moving only. Their weight was 52 ton, crew consisted of 6 men and its speed was lesser than of KV-1.

Soviet Heavy Tank KV-85 (Klim Voroshilov - 85mm)

The last mass modification of KV tank was the KV-85 model, produced during the autumn of 1943. On slightly changed hull of KV-1S the cast turret made for the later produced IS-1 was installed, armour of 100mm and 85mm gun. Weight was increased up to 46 ton, crew decreased to 4 members and machineguns to 2. Speed remains as it was.
At the end of 1943 tank KV was replaced by the new heavy tank IS-1. KV was the good construction of a heavy tank. Thanks to its superiority KV were seeking the encounters with the enemy tanks, while the German vehicles tried to avoid them. Soviet authors say that it always had the iniciative during the tank battles and that it was the mightiest tank of the world up to the end of 1942.