KV-122 Heavy Tank
It is often the case in many nations that instead of new tanks, industry preferred improved versions of tanks that were already in production. The Soviet tank industry was no exception in this regard. The main reason for putting improved tanks in front of brand new ones was ease of production.
After the Battle of Kursk, an order was given to develop a 122 mm tank and SPG gun with 1000 m/s muzzle velocity. Experience at the Battle of Kursk showed that a heavy tank needs a more powerful weapon than a D-5T gun. Such a gun, indexed D-25, was being developed by factory #9's design bureau. Calculations showed that the mass of the IS-85 with the D-25 gun grew to an acceptable 45-46 tons. The KV-85 and its potential modernization were a different story. The weight reached 47-48 tons, which was too much for the chassis.
The idea to improve the armament of the KV-85 was born at the Central Artillery Design Bureau (TsAKB), which was working on the S-34 family of guns. Like factory #9, the TsAKB was working on a triplex: three different barrels on one cradle. The number 34 was not used by accident, as the gun was based on the 100 mm B-34 naval gun. The KV-122 (1943), KV-100 (1944) and KV-122 (Object 239) (1944) were all prototype derivatives armed with a short 122 mm (4.8 in) howitzer (for indirect fire support), a long 100 mm (3.94 in), and a 122 mm (4.8 in) built and tested in 1943-44. The prototype KV-122 was created in the spring of 1944 by the Construction Bureau of the Chelyabinsk Kirov Plant on the basis of the KV-85 and differed from the latter in a turret with a 122-mm gun. The turret was copied from the IS-2 designed in 1944.
The last attempt to boost the firepower of the KV-85 was undertaken in the spring of 1944. This work was also done on personal initiative, but the initiator remains unknown. Documents on this topic are few. The resulting vehicle is often called KV-122, but it is not known if this index was really used. Based on existing information, the lead engineer of this project was A.S. Schneidmann. The recipe for this project was simple: the experimental Object 239 chassis was equipped with a production IS-2 turret with a sliding breech D-25 gun. These turrets were not installed on IS-2 tanks before February of 1944.
There is some doubt about the mass of the rearmed KV-85, which allegedly was only half a ton greater than the Object 239. Based on the difference between the IS-1 and IS-2, the real mass of the KV-122 would have been around 47 tons.
The engine was not as powerful as originally planned, but more reliable. Thereby it was necessary to sacrifice dynamic qualities for the sake of good work of the machine. The transmission was taken from the KV-85 tank, and in general a lot was taken from this tank, as well as from the IS-2. First of all, this is the tower, where the 122-mm caliber gun was placed, and despite the fact that the firing rate fell slightly, the firepower of the machine increased. It must be remembered that the IS-2 tank also had a low rate of fire, no higher than 2-3 rounds per minute.
It took several months to implement the design of the tank in metal, and the modification of the tank became known as the KV-122. The resulting heavy tank turned out to be very cheap in production due to the fact that it did not need to be created from scratch, but it was enough just to retool at the KV-85 plant.
The initiative was doomed from the start. After the conversion, the tank's mass rose, which reduced its mobility and reliability. In addition, there was no sense in performing this conversion. By the spring of 1944 at least half of all KV-85s have already been lost in battle. A rearmament program for such a small number of tanks made no sense. The idea of the KV-122 never reached the Main Directorate of Tank Repairs of the Red Army, which would have been its chief customer.
After the production of the IS heavy tanks started, all work on the project was discontinued. Only a few photos and pieces of information have survived. And, oddly enough, the KV-122 itself. The lower part of it in the form of the chassis of the Object 239 stands in the Avtovo area. And the upper part, that is, a turret with weapons, is displayed on the territory of the Kirov factory. It was placed on the chassis of an Object 237.
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