IS-2 Tank (Soviet Union)

The IS-1 and IS-2 heavy tank designs were based on the KV-1 and KV-13 medium to heavy tanks. They were the first major project for the Experimental Tank Factory in Chelyabinsk that was constructed by March, 1942. The experimental KV-13, armed with a 76 mm cannon, was already considered insufficient, so the design was abondoned and work began on designing a new tank on that base with an 85 mm main gun. They decided to name the tank the IS, after Ioseph Stalin (Russian pronunciation).

The new design was much smaller than the KV, which let the Soviets add additional armor and heavier weaponry without adding more weight. When the Germans began using Heavy Tiger tanks in late '42, the design process significantly sped up, but by that time they also realized that even the 85 mm cannon would be insufficient.

Kotin, the chief designer of Factory #100, was the first to suggest that the IS should be armed with a more powerful gun. In August of '43, after analyzing the results of the Battle of Kursk, he noticed that the 122 mm A-19 cannon had been more successful countering the Tiger than any other artillery system. Mounting a cannon that large on the IS would require redesigning it to allow for a barrel brake. The new tank armed with this gun was called the IS-122, and after preliminary testing, it was sent to Moscow for inspection. There its cannon was tested against a captured Tiger tank and it managed to blow it apart at 1,500 meters. During this test the A-19 cannon's barrel brake blew up, and Marshall Voroshilov, who was in attendance, was nearly killed, leading to the installation of a different model of the barrel brake.

The final design was named the IS-2. The strong armor and powerful main gun allowed it to go up against the latest German tanks and destroy them even from a mile away, as well as take out bunkers and other defensive positions. Although it had a small ammunition reserve and a low rate of fire, the IS tanks were vital when going against the German's strongest defenses and The IS-2's were instrumental in breaking through into the suburbs of Berlin

IS-2 Main Properties: Weight - 46.5 tons; Armour - up to 120 mm; Weapons - long-barrel 122 mm cannon and two 7.62 machine-guns; Engine - 520 hp; Speed - 37 kp/h (23 mph).