The Kliment Voroshilov (KV) tanks are a series of Soviet heavy tanks named after the Soviet defence commissar and politician Kliment Voroshilov who operated with the Red Army during World War II. The KV tanks were known for their heavy armour protection during the early stages of the war, especially during the first year of the German invasion of the Soviet Union. In certain situations, even a single KV-1 or KV-2 supported by infantry could halt German formations. The German Wehrmacht at that time rarely deployed its tanks against KVs, as their own armament was too poor to deal with the "Russischer Koloss" – "Russian Colossus".
The KV tanks were practically immune to the 3.7 cm KwK 36 and howitzer-like, short-barreled 7.5 cm KwK 37 guns mounted, respectively, on the early Panzer III and Panzer IV tanks fielded by the invading German forces. Until the Germans developed more effective guns, the KV-1 was invulnerable to almost any German weapon except the 8.8 cm Flak gun.
Prior to the start of Operation Barbarossa in June 1941, about 500 of the over 22,000 tanks then in Soviet service were of the KV-1 type. As the war progressed, it became evident that there was little sense in producing the expensive KV tanks, as the T-34 medium tank performed better (or at least equally well) in all practical respects. In fact the only advantage the KV had over the T-34/76 was its larger and roomier three-man turret. Later in the war, the KV series became a base for the development of the IS (Iosif Stalin) series of tanks and self-propelled guns.
Development history
After disappointing results with the multi-turreted T-35 heavy tank, Soviet tank designers started drawing up replacements. The T-35 conformed to the 1920s notion of a "breakthrough tank" with very heavy firepower though its armour protection was lacking and it suffered from poor mobility. The Spanish Civil War demonstrated the need for much heavier armour on tanks, and was the main influence on Soviet tank design just prior to World War II.
Several competing designs were offered, and even more were drawn up prior to reaching prototype stage. All had heavy armour, torsion-bar suspension, wide tracks, and were of welded and cast construction. One of the main competing designs was the SMK, which in its final form had two turrets, mounting one 76.2 mm and one 45 mm weapon. The designers of the SMK independently drew up a single-turreted variant and this received approval at the highest level. Two of these, named after the People's Commissar for Defence, were ordered alongside a single SMK. The smaller hull and single turret enabled the designer to install heavy frontal and turret armour while keeping the weight within manageable limits.
The KV was ordered right off the drawing board. When the Soviets entered the Winter War, the SMK, KV and a third design, the T-100, were sent to be tested in combat conditions. The KV outperformed the SMK and T-100 designs. The KV's heavy armour proved highly resistant to Finnish anti-tank weapons, making it more difficult to stop. In 1939, the production of 50 KVs was ordered. During the war, the Soviets found it difficult to deal with the concrete bunkers used by the Finns and a request was made for a tank with a large howitzer. One of the rush projects to meet the request was to put the howitzer in a new turret on one of the KV tanks. Initially known as 'Malen'kaya Bashenka' (little turret kv) and 'Bol'shaya Bashnya',(big turret kv) the 76-mm-armed tank was redesignated as the KV-1 Heavy Tank and the 152 mm howitzer one as KV-2 Heavy Artillery Tank.
KV tanks first faced the Germans in the Battle of Raseiniai, just after the start of Operation Barbarossa. On 23 June, over 200 German tanks advancing through Lithuania encountered Soviet armor, including KV-1 and KV-2 tanks. While their frontal armor was sufficient to deflect anti-tank fire, German troops were able to outflank them and destroy them with explosive charges or lure them to within point-blank range of direct-fire artillery. Of the more than 200 Soviet tanks lost at Raseiniai, 29 were KVs.