KV-3 heavy tank

The KV-3 experimental tanks were based on the KV-1 with a longer chassis (7 rollers per side vs 6). The first design (Object 221) was never built, but it was supposed to have a 85mm gun. The same thing happened to Object 222, which was supposed to have a F-32 76.2mm gun. The Objects 221 and 222 both used a new modified KV-1 turret. Object 223's hull was built and was tested with weights to simulated the new conical turret (housing a 107mm ZiS-6 cannon) that was designed for it. Object 223 had up to 120mm of sloped armor. Series production was intended to start in late 1941, but the German invasion of Russia halted these plans and the only prototype hull was destroyed.

After adopting the KV-1, it seemed that the unrestrained growth of the fighting mass of Soviet tanks had stopped. Instead of almost 60-ton QMS and T-100, the Red Army adopted a combat vehicle, which was almost a third lighter, although it had similar weapons and thicker armor. However, in the summer of 1940, work began on the creation of larger and heavier tanks of the KV family. In January 1941, the T-220 came out on trial, which exceeded the SMK and T-100 in combat weight. This tank became the harbinger of even heavier vehicles, which were to replace the KV-1 in production.

On March 15, 1941, a resolution was issued by the Council of People's Commissars of the USSR and the Central Committee of the CPSU (B.) No. 548-232, according to which the Kirov Plant began preparations for the production of a modified heavy T-150 tank. In the series, the modified tank, which bore the factory designation “Object 222”, had to carry the KV-3 index. In general, it was the same KV-1, but with an F-34 cannon, a slightly reworked turret with a commander's turret, a more powerful B-5 engine and an armor raised to 90 mm.

This activity, however, did not last long. Already at the end of March, foreign intelligence reported on the appearance of heavy tanks in Germany. What exactly the scouts had in mind is not completely clear. Nevertheless, the information received was taken very seriously. The development of more powerful anti-tank guns began, and in the tanks of the KV and T-34 family, work began on strengthening the booking and screening of existing tanks. Of course, serious changes have undergone and work on promising tanks. Already in the second decade of April 1941, work began on a new car, heavier than the T-150 and even the T-220.

On April 7, 1941, the Decree of the Council of People's Commissars of the USSR and the Central Committee of the CPSU (b) No. 827-345ss was issued, which established the technical characteristics of the new tank, which also received the KV-3 index. L. Ye. Sychev, who was later replaced by B. P. Pavlov, was appointed first as a machine engineer. The tank received a drawing cipher 223, and from time to time it was also called “Object 223”. Its combat weight was estimated at 67–68 tons, the turret’s armor thickness was 115 mm, the body’s forehead was 155–120 mm, and the sides were 90 mm. A 107-mm cannon was indicated as a weapon, as well as three DT machine guns. As the power plant was planned to establish 850-strong V-2SN. Prior to the development of a new engine in production, installation was allowed, with subsequent replacement by a B-2CH, 700-strong B-5.

The Kirov Plant was freed from the production of spare parts for the KV-1: this task was transferred to ChTZ. The task of producing the “former” KV-3 on the basis of the T-150, which received the designation KV-6, should gradually go there. It is worth noting that the Main Automobile Armored Directorate (GABTU) was against such a decision, suggesting instead of the 223rd to do the T-150 with a 76-mm cannon, having 3-K anti-aircraft cannon ballistics.

A new tank was not created from scratch. The KV-3 was a T-150 with an extended case, like the T-220, on which it was supposed to install a turret, also made on the model of the T-220 turret, with an 85-mm F-30 gun. From the very beginning it was stipulated that the turret would be produced by stamping. Even the construction of the hull for the prototype KV-3 was not made from scratch. The fact is that on February 10, 1941, a set of parts for the hull of an experienced T-221 tank (Object 221) arrived at the Kirov Plant. It was a T-150 with an elongated body, on which it was planned to install a KV-1 type turret with a 76-mm cannon. The tank was supposed to be assembled as early as December 1, 1940, but the Izhora Works delayed the shipment of parts for a number of reasons, and it was not up to it at the Kirov Plant.

In the aforementioned letter of Marshal Kulik, it was planned to install a 76 mm F-27 cannon with a 3-K anti-aircraft cannon ballistic into the T-221 turret. It was about the second model of the system, assembled in the autumn of 1940 - by the spring of 1941, it began to be called ZIS-5. These plans did not come true, since neither in February nor in March 1941 did anyone touch the T-221. The same thing happened with the case of SAU 212A. And in April, it was finally decided to use the T-221 case as the basis for the manufacture of the KV-3 case. The task was facilitated by the fact that the T-221 and KV-3 had the same thickness. It was necessary to strengthen only the front sheet.

The design work on a new tank, the Kirovsky Plant, began immediately after receiving the assignment from the NKTM (People's Commissariat of Heavy Machinery). In parallel with the design work, tests of the T-220 equipped with a B-5 engine were under way. It was this motor that was supposed to be installed in the KV-3 before mastering the production of V-2SN. The machine, loaded up to 70 tons, with torsions sagging 2–3 cm from such a load, traveled 150 kilometers from 12 to 15 April. Of course, the difference in 150 horsepower was felt, but on the whole the tank could drive with such a mass, so the B-5 was suitable as a temporary measure.

For the new tank, designer N. F. Shashmurin developed the gearbox, which was a development of the gearbox for the T-220. It should be noted that in parallel with it, the Military Academy of Mechanization and Motorization (VAMM) was entrusted with the development of an electric transmission. Transmission of this type, under the guidance of Professor N. I. Gruzdeva, was developed in WAMM earlier on its own initiative. The corresponding tactical and technical requirements were approved on April 29, 1941. At the same time approved and requirements for hydraulic transmissions. Employees of the All-Union Institute of Hydraulic Engineering took up its design.

By April 26, a full-size model of the KV-3 was prepared, which passed a preliminary inspection. According to his results, they decided to remove the aft machine gun DT, replacing it with a port for firing from the PCA. It was also recommended to install for the ZIS-6 cannon (the so-called F-42) a projectile rammer, a device in the stern for fastening the cannon in a marching way and somewhat to change the design of the turret. Adjustments were also made by the railroad workers, who demanded to reduce the width of the tank to 3410 mm. It was proposed to make a shot for the ZIS-6 unitary, and increase the ammunition to 60 shots.

The second time the commission examined the revised layout of the KV-3 on May 7, 1941. Together with the model, the commission got acquainted with a large amount of technical documentation. In addition to improvements, in the design of the tank appeared one important innovation. Instead of a course gun, a flamethrower of the construction of the plant #174 could now be installed on it. In general, the tank was approved, although a list of several dozen points for completion was compiled.

It should be noted that by that time the KV-3 was already considered as a temporary phenomenon. The thickness of armor chosen for him was based on the results of the shelling of armor plates by the German 88-mm anti-aircraft gun Flak 18. As for the outlook, even a 120 mm armor was now considered insufficient.

According to the results of the shelling of armor plates with a 105 mm Flak 39 anti-aircraft gun, purchased in Germany, it turned out that armor with a thickness of about 130 mm is needed to protect against this weapon. Since April 1941, the design of an even heavier KV-4 began, and then the KV-5. At the same time, everyone was well aware that work on the KV-4 and KV-5 would continue for a long time. Therefore, for 1941, the KV-3 definitely remained a priority.

According to the supplementary agreement to contract No. B1-081, signed on June 5, 1941, the Kirovsky plant undertook to produce for 1941, as many as 500 KV-3. The first 55 tanks were planned to receive as early as August 1941, 105 - in September, 110 each in October and November, and 120 - in December. The price for one tank was 740 thousand rubles. For comparison, the KV-1 cost 523 thousand, and the KV-2 - 558 thousand rubles. German Pz.Kpfw. Tiger Ausf.E cost 400 thousand Reichsmarks (at the rate of 1940 it is 840 thousand rubles), and Pz.Kpfw. Tiger II - 321,500 Reichsmarks, (675,150 rubles).

As of May 13, 1941, the equipment for its manufacture was only partially ready, in fact, it was only possible to start stamping prototypes by mid-June. Work was also delayed on the manufacture of the hull: it was also begun only in June. The second sample of the ZIS-6 cannon arrived at the Kirov Plant in May, but the ground tests of this system began only at the end of June 1941. In this form, the KV-3 met the beginning of the Great Patriotic War.

The beginning of the war very quickly changed the course of work on prospective projects. On June 26, 1941, Order No. 255CC was issued for the People's Commissariat of Heavy Machinery, according to which the task of mastering the new heavy tank was shifted to CTZ. The same order was duplicated on June 30, 1941 at the Kirov Plant. At the same time, the order stopped work on the KV-4 and KV-5, although in practice the design of the KV-5 proceeded until the evacuation of the Kirov factory. According to the factory order, 18 design engineers were transferred to Chelyabinsk, including Dukhov, Pavlova and Shashmurin. As for the prototype, it was decided to assemble the case, equipping it with a serial chassis and an engine from the T-220. Together with the chassis, the stamped billets of the turrets, as well as all the equipment involved in the manufacture, were sent to Chelyabinsk.

At the beginning of July 1941 the half-assembled KV-3 and its turret were loaded onto two platforms and sent to Chelyabinsk. It is believed that the story of this tank is actually over, since mass production was never established. Moreover, even the assembly of the prototype was not finished.

In fact, this is not the case, as archival documents eloquently indicate. As already mentioned, the test sites of the ZIS-6 began only in the month of June, namely, on the 25th, after the start of the war. During the tests, which took place before July 5, 618 shots were fired. On the one hand, tests showed good armor penetration, amounting to 120 mm at a distance of 1600 meters. On the other hand, claims were made to the system related to the insufficient strength of a number of nodes. After eliminating these shortcomings, the mass production of the ZIS-6 was given a green light.

The design bureau of the plant #92 did not stop at this. On the initiative, a revised version of the gun was developed, which received the ZIS-6A index. This installation, some authors mistakenly considered the development of an assault tank KV-7, which is not true. The deadline for completion of the work was 1 May 1942. By July 1942, completion of work on the electric transmission for the KV-3 was expected, and by December 1942, the production of a two-stroke diesel engine based on B-2 was to be completed. The engine had to have 1200 horsepower.

The grave-digger of the KV-3 was his older brother, the KV-1, or rather, the low reliability of the transmission of this tank. Due to the constant increase in the thickness of the armor and with it the growth of mass, the KV-1 began to pursue permanent damage. Particularly suffered transmission. Since the spring of 1942, work began to reduce the mass of the tank, and this was done as directed from above. In such conditions, the almost 70-tonne KV-3 was definitely out of work.

It remains only to regret that the KV-3 was never assembled and tested. And not because these almost 70-ton tanks, superior in all basic characteristics to their foreign counterparts, could change something during the war. Although at the expense of a much more powerful booking, the KV-3 would have been a really tough nut to the Germans, the matter is quite different.