When it comes to the most successful tanks of the Second World War, the first thing to remember is the Soviet T-34 and the German Tiger. A little less often people remember the domestic IS tank and the German Panther. But the KV tank is traditionally overlooked even by some history buffs. But it was the KV-1 that became an unpleasant surprise for the Wehrmacht in 1941. On the account of KV feats there are no less than on the account of 34. Much more important is the fact that most of them fell precisely at the beginning of the war.
It is after the Second World War that mankind will finally come to the idea of creating a "single tank" for its armies. And before the start of the worst war in history, designers of all countries worked and created under the strongest influence of the experience of the First World War. That is why the assortment of various tanks was truly wide: light, medium, heavy with large-caliber cannons or with machine guns alone … In all this "zoo" the KV tank was developed precisely as a heavy vehicle with a representative weapon and solid armor.
The development of the KV began back in 1938, along with other heavy tanks such as the T-100 and SMK. The Baptism of Fire was already adopted by the KV during the Finnish War of 1939-1940. Although the new heavy tanks, in fact, took part only in the final stage of the military campaign, they were able to fully reveal their potential. It became clear to the army leadership that the KV was the only viable model of a heavy tank. The QMS and T-100 concepts were finally rejected. However, the KV itself underwent changes: they added more armor and removed the second smaller-caliber cannon, leaving only the 76-mm, like in the first T-34s.
Although the KV-1 performed well in the Winter War, the tank turned out to be frankly raw. A solid booking, in fact, was the only trump card of the car. The already mentioned 76-mm gun was not bad for the late 1930s, but it still did not give the tank a decisive superiority, just as it did not allow it to be used against enemy fortifications. But the most important thing was that the KV-1 had a whole lot of various technical problems with the electrics, engine and transmission. By 1941, the designers managed to eliminate a significant part of the shortcomings, but the car was still "raw". The tank also suffered from a frankly weak engine, which, coupled with heavy armor, made the KV-1 very clumsy.
However, the KV-1 crews were able to make their contribution to the victory (and not a small one) already at the beginning of the Great Patriotic War. This became possible thanks to the solid armor of the tank. "Kliment Voroshilov" became that beast on the battlefield, which was virtually invulnerable to most German tanks at the beginning of the war. Light tanks Pz. Kpfw. 38 and even medium Pz. Kpfw. IVs could not cope with the KV-1 armor at the initial stage of the war. It is also important that the German anti-tank field artillery in the person of Pak 36 and PaK 41 guns turned out to be practically useless against Soviet heavy tanks in 1941. To destroy the KV-1, the Wehrmacht had to use 88-mm anti-aircraft guns and 150-mm divisional artillery. At the same time, even the 76-mm KV-1 cannon quite effectively coped with the Wehrmacht medium tanks.
There were frequent cases when KV-1 units, and sometimes individual single tanks, turned into real mobile fortresses, stopping for hours and even days the advances of superior enemy forces in certain directions. So in 1941, near Raseiniai, a lone KV gave battle and for several hours held back a superior enemy. In 1942, a similar episode took place near the Nizhnemityakin farm in the Rostov region, where a lone KV also detained a superior enemy. Separate tank platoons of the KV-1 in 1941 managed to stop entire tank columns of the Wehrmacht, operating from an ambush. In the end, heavy Soviet tanks made an indelible impression on German tankmen and artillerymen.
However, 1942 came. New heavy tanks of the Wehrmacht appeared at the front. The Reich menagerie was replenished with "Tigers" and "Panthers", which possessed representative armor and powerful cannons. More importantly, the Germans were able to improve the armor of all tanks, and also developed new types of shells with better armor penetration. The KV-1 tank, which in addition to armor did not have any decisive advantages in comparison with the T-34-76 medium tank, gradually began to leave the battlefields. Moreover, the legendary 34 came out cheaper and, most importantly, more reliable. The KV-1 was produced until 1942, when it was finally replaced by more advanced domestic machines.
If you want to know even more interesting things about Soviet technology, then you should read about what is "Mass grave": why did the Red Army men so nicknamed the SU-76.