KV-1 Heavy Tank from the front right |
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The KV-1 Heavy Tank was almost invulnerable to German anti-tank guns in 1940, but was soon let down by its limited firepower and mobility, and was obsolete by 1943.
The KV-1 was one of several designs produced to replace the T-35 heavy tank, and the only one to have a single turret. It was designed by the Kirov design bureau at Leningrad, who believed that the multiple turrets used on the T-35 and the rival designs to replace it were too difficult to control in combat. The new design was similar in weight to the T-35, but was 10ft shorter in length and 2ft shorter in height. The initial version was armed with a short 76.2mm gun. It was named after Klimenti Voroshilov, who was then the Commissar for Defence.
Prototypes of three different designs were produced. The other two designs, the T-100 and the SMK both had two turrets.
In late 1939 all three prototypes were sent to Finland for combat trials with the 20th Armoured Brigade, which was commanded by Voroshilov’s son P. Voroshilov. They were used in an attack on the ‘Velikan’ bunkers near Summa. The SMK was immobilised when one of its tracks was blown off by a mine. The KV and T-100 were used to guard the tank, while T-28s attempted to rescue it. Of the three the KV performed the best, so on 19 December 1939 it was ordered into production. Two versions were ordered – the gun armed KV-1 and the 152mm howitzer armed KV-2.
A large number of designs based on the KV-1 were produced, although very few of them reached production. The KV-1S was an attempt to compensate restore performance by removing the extra armour added in later versions of the standard KV-1, but was unpopular because it still carried the same 76.2mm gun. The KV-85 was an interim design that matched the KV-1 chassis and hull with the new turret that would be used on the IS-1 heavy tank. The SU-152 was a self propelled gun that matched the chassis of the KV-1 with a new superstructure carrying a 152mm gun.
The KV family were eventually replaced by the Josef Stalin tanks, with the IS-2 being the main combat version. This combined the turret used on the KV-85 with a new hull and drive train and was armed with a powerful 122mm gun. However unlike the KV-1 it wasn’t meant for tank-vs-tank battles, but instead to lead attacks on German fortifications, while the T-34-85 and various tank hunters tackled the German tanks.
Design
The KV-1 was powered by a 600hp V-2K engine, the same engine used in the T-34. It used a dry multi-plate clutch and a sliding mesh gearbox. The sliding mesh gearbox was mechanically efficient when in gear, but made it more difficult to change gears. The biggest problem was that the transmission wasn’t strong enough to cope with the weight of the KV-1 and thus proved to be very fragile.
The driver sat at the centre-right of the hull, with the gunner/ radio operator on the left. Unlike the T-34, most KV-1s carried a radio, although this was normally a 71-TK-3 set which was somewhat temperamental.
The KV-1 had a three man turret, but with a rather unusual layout. Instead of containing a gunner, loader and commander, the turret contained the gunner, commander/ loader and assistant driver/ engineer. In combat the assistant driver’s only role was to man the rear facing machine gun carried in the back wall of the turret. The commander had to load both the main gun and the coaxial machine gun. The rear seat had no all round vision devices, making it impossible to simply move the commander to the rear. This had a major impact on the KV-1’s performance in combat, as the commander was often distracted from his main job by the need to reload the guns. Unsurprisingly it became common for the KV-1 to only carry a crew of four.
Production
The KV-1 and KV-2 entered production at the Kirovskiy Plant in Leningrad. The Soviets realised that the city was potentially vulnerable and in 1940 began work on a second KV production line at Chelyabinsk, in the Ural Mountains. This would eventually become known as Tankograd, but it would take some time to build up production there. As the Germans approached Leningrad the factory there was evacuated to Tankograd. The move was completed by October 1941, and of the 1,358 KV tanks built in 1941 an impressive 629 were built at Chelyabinsk.
Once the move was complete all KV tanks were assembled at Tankograd. However hulls were also built at the Uralmash Plant in Sverdlovsk.
Combat Record
When the Germans invaded in June 1941 the Soviets had about 500 KV-1 tanks in service. Like the T-34 they came as a nasty surprise to the Germans, with better armour and better guns than the newest German tanks. Neither the Panzer IIIs nor Panzer IVs of 1941 could cope with the KV-1. It was only really vulnerable to the famous German 88mm Flak gun. However in 1941 there weren’t enough KV-1s to have a significant impact on the fighting, and they suffered from the same problems as other Soviet tanks of 1941 – poor crew training, poor tactics and mechanical unreliability. More KV tanks were abandoned after breaking down than were destroyed by the Germans. Superior German tactics meant that they were normally able to find a way around the KV forces.
As the Germans introduced more powerful anti-tank weapons the thinner armour of the T-34 became vulnerable first, giving the KV-1 a valuable role as it remained difficult to damage for longer. However once the Germans had developed weapons that could cope with the KV-1’s armour it lost its purpose. The T-34 was armed with the same 76.2mm gun, was lighter and thus more mobile and could be produced in much larger orders. As a result the KV-1 was phased out in favour of the IS-2, armed with a much larger 122mm gun.
During the fighting in 1941 small numbers of KV-1s could inflict heavy damage on German units. Perhaps the most famous example of this came at Raseiniai in June 1941, when a single KV-1 (or KV-2) became isolated far behind German lines. The tank took up a position blocking the one road across an area of soft ground, and managed to hold off a kampfgruppe from the 6th Panzer Division on 24-25 June. During the battle it knocked out four 50mm anti-tank guns and an 88mm gun, survived an attack with satchel charges and was finally knocked out when grenades were either thrown through an open hatch or holes punched in the turret by German fire.
An even more successful engagement came in August 1941 at Krasnogvardeysk on the approaches to Leningrad. Here five well hidden KV-1s, commanded by the second most successful Soviet tanker ace of the war, Zinoviy Kolobanov, managed to know out 43 German tanks, mainly Panzer IIs and Panzer IIIs. Kolobanov’s career demonstrated many of the perils of service in the Red Army. He had been a captain during the Winter War, but was demoted to lieutenant for ‘fraternizing with the enemy’. He was awarded the Order of Lenin for his achievement at Krasnogvardeysk, but was badly wounded on 15 September 1941 in an accident behind the lines and missed the rest of the war. His status as the second highest scoring Soviet tank ace thus came from the first few months of the war. He remained in the army after the war, and served in the Soviet Occupation Zone in East Germany. However he was court-martialed and transferred to the reserves after a subordinate escaped to the British zone.
As the Germans introduced more powerful tank guns the KV-1 began to lose its advantage. The 75mm long guns used in later Panzer IVs could penetrate its armour. The 76.2mm gun was no better than the gun carried in the T-34, which was much cheaper to produce, faster and more mobile. In the summer of 1942 the KV-1s were removed from the mixed armoured regiments and concentrated in independent tank brigades, solving the problem of having two tanks with very different performance in the same unit. Tanks produced in 1941 and 1942 carried thicker armour, which further reduced their performance. In an attempt to restore some speed the lighter KV-1S was produced in 1942-43, but this was unpopular with the tank forces as it still carried the same gun. A small number of KV-85s were built 1943 as a stop-gap measure before the IS series entered production.
A number of KV tanks were still in use during the battle of Kursk. However they only represented 205 of the 3,400 Soviet tanks on the Central Front. The KV-1 had now gone from being dominant to being very vulnerable – its gun couldn’t penetrate the armour of the new Tiger I or Panther tanks at normal ranges, and its armour could easily be penetrated by the German tanks at the same range.
Main Variants
During the war the Soviets didn’t give the different versions of the KV-1 distinct designations. However in the post-war period four main sub-versions were identified, using key changes – in particular to the gun – using model years. During the war the Germans had produced their own designation system for the KV, in this case using letters. The post-war model year system tends to match the wartime German system. However because of the chaotic nature of tank production after the German invasion individual KV tanks could carry a mix of features of different ages. As a result it was possible to find tanks with many different combinations of guns, turrets and armour.
KV-1 Model 1939 (KV-1)
The KV-1 Model 1939 was the first production version of the tank and was armed with the short barrelled L-11 76.2mm gun. This type was used later in the Winter War against Finland where its thick armour made it difficult for the Finns to deal with. About 141 were built. It weighed 45 tons. On the Model 1939 the gun was located towards the bottom of the mantlet.
KV-1 Model 1940 (KV-1A)
The Model 1940 was armed with the improved F-32 76mm gun. This was the main version in production when the Germans invaded in 1941. The new gun was carried high in the mantlet, making it easy to tell the first two models apart.
Some examples of the Model 1940 were built with bolt-on appliqué armour as were known as the ‘s ekranami’ or ‘with shields’, or the KV-1E. It was three tons heavier than the standard Model 1940.
KV-1 Model 1941 (KV-1B)
The Model 1941 was armed with the long barrelled ZiS-5 76mm tank gun. It had extra armour on the turret and the front and sides of the hull. Some later tanks had cast turrets.
KV-1 Model 1942 (KV-1C)
The Model 1942 had a fully cast turret with thicker armour and carried extra hull armour. It was give an improved engine, but kept the ZiS 5 gun. This was the heaviest version, at 52 tons.
The KV-1S was produced in response to the drop in performance caused by added extra armour without extra engine power. The extra armour added on later versions was removed. It was given a new smaller cast turret. The rear of the hull was designed and a new planetary transmission used. Weight came down to 45 tons, the same as the original KV-1. Around 1,370 were built, but they had even less advantage over the T-34 than the normal KV-1.
The KV-2 had a massive turret carrying a 152mm howitzer. It was only produced in small numbers because the turret made it awkward to move and an easy target.
Two versions of the KV-8 flamethrower tank were produced, the first 102 armed with an ATO-41 flamethrower, the last 35 with an improved ATO-42 flamethrower.
The KV-85 was a stop-gap design which combined the chassis of the KV-1S with the new turret of the IS-1, armed with an 85mm gun. Only 130 were built.
SU-152
The SU-152 was a successful heavy assault gun and self propelled anti-tank gun that carried a 152mm gun howitzer in a fixed fighting compartment on the chassis of the KV-1S. A small number fought at Kursk in 1943 where they performed well. When production of the KV-1S ended, work moved onto the ISU-152 and ISU-122, the same basic design but using the IS chassis.
Minor Variants
The KV-3 was a more heavily armoured development of the KV-1, with an improved turret. It was accepted for production in 1941 but cancelled after the German invasion.
The KV-4 was a series of designs for an even heavier tank, to be armed with a 107mm tank gun. None entered production.
KV-5
The KV-5 was another
The KV-7 was an attempt to mount two or more assault guns on the chassis of a KV heavy tank. Two different designs reached the prototype stage but the idea was badly flawed and it never entered production.
The KV-9 was a design for a heavy tank armed with a 122mm howitzer. One prototype was built but the higher trajectory of the howitzer made it more difficult to aim than normal tank guns and the type didn’t enter production.
The KV-12 was a design for an assault gun armed with a 203mm howitzer. It was produced alongside the KV-14, which became the SU-152, and only reached the prototype stage.
The KV-13 was a design for a ‘universal tank’ which was to replace the T-34 and KV-1. It would have been lighter than the KV-1 but armed with the same 76mm gun. However it was abandoned after the appearance of the Tiger and Panther showed that heavier guns were needed. Some aspects of the KV-13 design were used on the IS-1 and later members of that family.
S-51
The S-51 was an experimental self propelled gun which had a 203mm howitzer mounted on a KV-1S hull. A prototype was built but it never entered production.
Stats (Model 1941)
Production:
Hull Length: 22ft 2in
Hull Width: 10ft 11in
Height: 8ft 11in
Crew: 5
Weight: 45 tonnes
Engine: 600hp V-2K diesel engine
Max Speed: 22mph
Max Range: 160 miles road, 93 miles cross country
Armament: 76.2mm M1941 ZiS-5 gun, three or four DT machine guns
Armour: 90mm front, 75mm sides, 70mm rear
KV-1 from the left 
KV-1 in the woods 
KV-1 Model 1941 Heavy Tank in Moscow