The Russian KV-3 Heavy Tank

The Russian KV-3 Heavy Tank

The Russian KV-3 Heavy Tank was intended to be the replacement of the KV-1. Development had started during 1940 (prior to Operation Barbarossa) of an up armoured and up gunned heavy tank by the Kirov tank factory.

Two prototypes were built and trialled:

Prototype 1. Designated the T-150, it was an up armoured KV-1 with 90mm thick frontal steel and a 76mm main gun. It had an improved cupola and a new 700hp engine.

Prototype 2. Designated the T-220, it was fitted with a new turret mounting the 85mm F-30 main gun and had 100mm of thick frontal steel. It had a longer hull with an additional road wheel.

Trials of both vehicle in early 1941 high-lighted a number of issues with the 700hp engine of the T-220 not being able to cope with the vehicles 62 tonnes weight. The army went with the T-150 design and was designated the KV-3 in March 1941.

However on the 7th of April 1941 the army set new requirements for the KV-3, which included the front-slope armour was to be thickened to 115mm(+), the turret armour was to be 115mm thick and it was to be armed with the ZIS-6 107mm main gun which had a muzzle velocity of 800 m/s.

This revised KV-3 design resulted in a heavier tank of roughly 70 tonnes. So the T-220 prototype aka the KV-220 was fitted with a 800hp engine and used for testing the new assemblies and aggregates of the revised design. By the end of May 1941 it had completed over 1000km’s of trials, with limited success. The vehicle was then repaired and fitted with a 850hp V-2SN diesel engine. This prototype was recorded as KV-220-1.

A second prototype was built at some stage and recorded as KV-220-2.

It is not clear which of the two prototypes was fitted with the new turret developed to mount the 107mm main gun and pictured at the top of the page as a completed tank, but it is most likely to be KV-220-2, as this is recorded as the incomplete KV-3 tank at the plant.

Neither the earlier KV-3 design which was the T-150, nor the revised KV-3 design entered production. However all three prototypes were later fitted with the KV-1 production turret mounting the 76mm main gun and were issued to the army in late 1941 and were used in active service.

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