The Kliment Voroshilov (KV) tanks were a series of Soviet heavy tanks, named after the Soviet military commander and politician Kliment Voroshilov. At the time of the German invasion of the Soviet Union in World War II these were amongst the large number of Soviet tanks that were superior to German tanks.
| KV1 model 1941 | |
|---|---|
KV1 model 1940 s ekranami ("with appliqué"), or KV1-E | |
| Specifications | |
| Mass | 45 |
| Length | 6.75 |
| Width | 3.32 |
| Height | 2.71 |
| Crew | 5 |
History
After disappointing results with the multi-turreted T-35 heavy tank, Soviet tank designers started drawing up replacements.
One of the main competing designs was the SMK, which lowered the number of turrets from five to two. When two prototypes were ordered though, it was decided to create one with only a single turret, but more armour. This new single-turret tank was the KV.
When the Soviets entered the Winter War, the SMK, KV and a third design, the T-100, were sent to be tested in combat conditions. The heavy armour of the KV proved highly resilient to Finnish anti-tank weapons, making it more effective than the other designs. It was soon put into production, both as the original 76-mm-armed KV-1 Heavy Tank and the howitzer-mounting assault gun, the KV-2 Heavy Artillery Tank.
While the KV was virtually unstoppable by conventional attack, it had serious flaws in nearly every other aspect. It was slow and unmaneuverable, and used the same gun as smaller medium tanks. Most damaging was its terrible reliability, as many more KVs were taken out of operation due to mechanical problems than due to enemy action. As an example, its transmission gears were so poor that many drivers had to use hammers to shift.
When Operation Barbarossa began, the Red Army was equipped with 639 KV-1s. So effective was its armour that the Germans were incapable of destroying it with their tanks or anti-tank weapons and had to rely on air support and artillery to knock them out. At one point, a large German armoured group was delayed for 2 days by a single KV-1 near Ostrov.
Because of its superior performance, the KV-1 was chosen as one the few tanks to continue production following the Soviet reorganization. Due to the new standardization, it shared the same engine, gun and transmission as the T-34, was built in large quantities, and received frequent upgrades.
As the war continued, the KV-1 continued to get more armour to compensate for the increasing effectiveness of German weapons. This culminated in the KV-1 model 1942 (KV-1C), which was protected by very heavy armour, but lacked a corresponding improvement to the engine. Tankers complained that although they were well-protected, their mobility was poor and they had no firepower advantage over the T-34 medium tank. The Soviet heavy tank program was in jeopardy, and Stalin nearly cancelled heavy tank production in the summer of 1943.
In response to criticisms, the lighter KV-1S (Russian language: КВ-1С) was released, with a few technical improvements and the shedding of armour in order to reclaim some speed. Ironically, this reduced the only advantage the tank ever really had, and it was now clearly overshadowed by the cheaper and more versatile T-34.
The Soviet heavy tank designers also embarked on an ambitious "KV-13" program, to fix the heavy tanks' deficiencies. An advanced overall redesign was undertaken, armed with an 85mm gun.
A stopgap upgrade to the KV series was the short-lived KV-85. This was a KV-1S with a new turret designed for the KV-13, mounting the same 85 mm D-5T gun as the T-34/85. Already high demand for the gun slowed production of the KV-85 tremendously, and only 130 were built before the series was cancelled in 1944.
Because Kliment Voroshilov had fallen out of political favour, the KV series was renamed IS, after Iosif Stalin. The KV-13 program's IS-85 prototype was accepted for production as the IS-1 heavy tank, but in the mean time, field tests showed that the larger A-19 122mm gun could defeat the armour of the German Panther tank. The IS-122 design replaced the IS-85, and began mass production as the IS-2. 85mm guns could be reserved for the T-34/85 medium tank, and the few IS-1s were upgunned before being issued.
Models
Note: the Soviets did not recognize production models of KV-1 during the war, therefore designations like model 1939 (or M1939, Russian: Obr. 1939) were introduced later in military publications. These designations however are not strict and describe leading changes, while other changes might be adapted earlier or later in specific production batches. Designations like KV-1A were applied by the Germans during the war.
- KV-1
- Model 1939 – First production models, these tanks were prone to frequent breakdowns, but were highly resilient to anti-tank weapons during the Winter War. These tanks were armed with the 76 mm L-11 tank gun, recognizable due to a recuperator above a barrel. Most tanks were lacking the hull machine gun. 141 were built.
- Model 1940 (German designation: KV-1A) – Used the F-32 76 mm gun and a new mantlet. The main production model by the time of the German invasion.
- Model 1940 s ekranami ("with screens") or KV1-E – with additional bolted-on appliqué armour.
- Model 1941 (KV-1B) – Up-armoured with 25 to 35 mm added to the turret, hull front and sides. Turret was now cast instead of welded. Later versions of this tank used the 76 mm ZiS-5 tank gun with longer barrel.
- Model 1942 (KV-1C) – Fully cast turret with thicker armour or welded turret with thicker armour, again up-armoured and used an improved engine and the 76 mm ZiS-5 tank gun.
- KV-1S – A lighter variant of late 1942 with higher speed, but lowered armour. There were also numerous technical improvements and a redesign of the rear hull. 1370 were built
- KV-85 – A KV-1S with the 85 mm D-5T gun in an IS-1's turret, 130 of these tanks were produced in September-October 1943 as a stopgap until the IS tank series entered production.
- KV-13 - Prototype designation for an advanced redesign of the KV series, which was renamed and resulted in the production of the IS-2.
Variants
- KV-2 (334) – A heavy assault tank with the M-10 152 mm howitzer, the KV-2 was produced at the same time as the KV-1. Due to the size of its heavy turret and gun, the KV-2 was slower and had a much higher profile then the KV-1. The extra weight also increased the breakdown rate of the vehicle and production was soon halted. The original KV-2 was built on the chassis of the KV-1, while the improved KV-2B was built on that of the KV-1 M1940.
- KV-8 (42) – A KV-1 fitted with the ATO-41 flame-thrower in the turret, beside a machine gun. In order to accommodate the new weapon, the main gun was restricted to a smaller 45 mm Gun M1932, though it was disguised to look like the standard 76 mm.
- KV-8S (25) – A KV-1S with the coaxial turret machine gun replaced by an ATO-41 flame-thrower, and the main gun restricted to a 45mm.
- KV-14 – Prototype designation for a 152mm self-propelled gun, accepted for service as the SU-152.
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