At the end of 1941, SKB-2 developed the KV-8 flamethrower tank and the KV-12 chemical tank based on the KV-1 tank, as well as the KV-7 self-propelled artillery gun and the KV-9 tank together with the UZTM design bureau. The KV-8 tank was mass-produced, the KV-12 chemical tank and the KV-7 self-propelled gun remained in prototypes.
The KV-9 tank, armed with a U-11 122-mm howitzer, was created as a powerful universal means for breaking through enemy fortified zones, destroying defensive structures and destroying tanks. The design of the installation of a howitzer in the tower of the KV-1 tank at the UZTM design bureau showed that, along with minor changes in the design of the tower, for the rational placement of the artillery system itself, a radical alteration of many of its components was required. In January 1942, a prototype machine was manufactured at ChKZ. In April, NKV plant No. 9 manufactured a small series of U-11 howitzers for the KV-9 tanks. The KV-9 tank was successfully tested, but the decline in the manufacturing quality of the KV-1 transmission and the increase in its mass led to a catastrophic number of accidents at the front. The fear of further deteriorating the operating conditions of the transmission if a 122-mm howitzer was installed on the tank led to the refusal to accept the KV-9 into service.
The mass of the tank was 47 tons, the crew consisted of only 4 people: two were located in the tower, two in the hull.
The tank had a slightly modified cast turret from the KV-1. To protect the tank from anti-tank artillery fire, its frontal armor reached a thickness of 135 mm, the thickness of the turret roof - 40 mm. The tank was equipped with a telescopic sight TMFD. Vertical guidance angle -4 ° +19.5 °. For firing, ammunition from the M-30 howitzer was used. The ammunition capacity of the tank was 48 rounds for the gun and 2646 rounds for three 7.62 mm DT machine guns.
There were a lot of experienced KVs.
For example, the KV-220 with an 85 mm anti-aircraft gun, he even managed to fight in August 1941 during the defense of the Kirovsky district of Leningrad, or the lightweight KV-13 with a 76 mm cannon, 120 mm frontal armor and a five-roll chassis (the IS-1 was created on its basis), as an intermediate link between medium and heavy tanks, a sort of station wagon - as average in weight and as heavy in protection.
KV-220
There was also an experimental version of the KV-1S with the Grabin S-41 (in fact, a short tank gun with a caliber of 122 mm, the ammunition and ballistics were similar to the M-30 divisional howitzer). Appearance - similar to the KV-9, but the gun has a two-chamber muzzle brake. Mentioned (and is in the photo) in the books of M. Svirin "Stalin's steel fist" and "Stalin's self-propelled guns".
Soviet tank crews mastering new KV-1S tanks
There are several reasons for not adopting heavy tanks armed with howitzers (and in fact shortened guns with deteriorated ballistics), but in particular, their low suitability for fighting enemy tanks.
The bottom line is the following: for the gun, a "armor-burning" (in the terminology of that time) is being developed, which should, from 500 m, ensure the penetration of a cumulative jet of more than 100 mm. normal armor. But during tests from a given distance from this gun it is not possible to hit the enemy tank! More or less accurate shooting began at distances of 200 m and less. So I had to use 85 mm first. guns on the KV-85, and then on the IS tanks to switch to 122 mm. guns with ballistics similar to the hull A-19.
And in terms of artillery support for troops, self-propelled guns on the chassis of medium tanks became a cheaper and more affordable means.
