Kliment Voroshilov tank Information

The Kliment Voroshilov (KV) tanks, a series of Soviet heavy tanks named after the Soviet defence commissar and politician Kliment Voroshilov, operated with the Red Army during World War II. The KV tanks were known for their heavy armour protection during the early stages of the war, especially during the first year of the German invasion of the Soviet Union. In certain situations, even a single KV-1 or KV-2 supported by infantry could halt large German formations. The German Wehrmacht at that time rarely deployed its tanks against KVs, as their own armament was too poor to deal with the "Russischer Koloss" – "Russian Colossus".

The KV tanks were practically immune to the 3.7 cm KwK 36 and howitzer-like, short-barreled 7.5 cm KwK 37 guns mounted, respectively, on the early Panzer III and Panzer IV tanks fielded by the invading German forces. Until the Germans developed more effective guns, the KV-1 was invulnerable to almost any German weapon except the 8.8 cm Flak gun.

Prior to the start of Operation Barbarossa in June 1941, about 500 of the over 22,000 tanks then in Soviet service were of the KV-1 type. As the war progressed, it became evident that there was little sense in producing the expensive KV tanks, as the T-34 medium tank performed better (or at least equally well) in all practical respects. In fact the only advantage the KV had over the T-34/76 was its larger and roomier three-man turret. Later in the war, the KV series became a base for the development of the IS (Iosif Stalin) series of tanks and self-propelled guns.

After disappointing results with the multi-turreted T-35 heavy tank, Soviet tank designers started drawing up replacements. The T-35 conformed to the 1920s notion of a "breakthrough tank" with very heavy firepower and armour protection, but suffered from poor mobility. The Spanish Civil War demonstrated the need for much heavier armour on tanks, and was the main influence on Soviet tank design just prior to World War II.

Several competing designs were offered, and even more were drawn up prior to reaching prototype stage. All had heavy armour, torsion-bar suspension, wide tracks, and were of welded and cast construction. One of the main competing designs was the SMK, which in its final form had two turrets, mounting one 76.2 mm and one 45 mm weapon. The designers of the SMK independently drew up a single-turreted variant and this received approval at the highest level. Two of these, named after the Peoples Defence Commissioner, were ordered alongside a single SMK. The smaller hull and single turret enabled the designer to install heavy frontal and turret armour while keeping the weight within manageable limits.

The KV was ordered right off the drawing board. 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 KV outperformed the SMK and T-100 designs. The KVs heavy armour proved highly resistant to Finnish anti-tank weapons, making it more difficult to stop. In 1939, the production of 50 KVs was ordered. During the war, the Soviets found it difficult to deal with the concrete bunkers used by the Finns and a request was made for a tank with a large howitzer. One of the rush projects to meet the request put the howitzer in a new turret on one of the KV tanks. Initially known as Little turret KV and Big turret KV, the 76-mm-armed tank was redesignated as the KV-1 Heavy Tank and the 152 mm howitzer one as KV-2 Heavy Artillery Tank.

KV tanks first faced the Germans in the Battle of Raseiniai, just after the start of Operation Barbarossa. On 23 June, over 200 German tanks advancing through Lithuania encountered Soviet armor, including KV-1 and KV-2 tanks. While their frontal armor was sufficient to deflect anti-tank fire, German troops were able to outflank them and destroy them with explosive charges or lure them to within point-blank range of direct-fire artillery. Of the more than 200 Soviet tanks lost at Raseiniai, 29 were KVs.

The KVs strengths included armour that was impenetrable by any tank-mounted weapon then in service except at point-blank range, that it had good firepower, and that it had good flotation on soft ground. It also had serious flaws: it was difficult to steer; the transmission (which was a twenty-year-old Holt Caterpillar design) "was the main stumbling block of the KV-1, and there was some truth to rumors of Soviet drivers having to shift gears with a hand sledge"; and the ergonomics were poor, with limited visibility. Furthermore, at 45 tons, it was simply too heavy. This severely impacted the maneuverability, not so much in terms of maximum speed, as through inability to cross many bridges medium tanks could cross. The KV outweighed most other tanks of the era, being about twice as heavy as the heaviest German tank at that time (before the Tiger). As appliqué armour and other improvements were added without increasing engine power, later models were less capable of keeping up to speed with medium tanks and had more trouble with difficult terrain. In addition, its firepower was no better than that of the T-34. It took field reports from senior commanders "and certified heroes", who could be honest without risk of punishment, to reveal "what a dog the KV-1 really was".

By 1942, when the Germans were fielding large numbers of long-barrelled 50 mm and 75 mm guns, the KVs armour was no longer impenetrable, requiring the installation of additional appliqué armour. The KV-1s side (favorable approach: 30° degree at 300–500 m distance), top, and turret armour could also be penetrated by the high-velocity Mk 101 30 mm cannon carried by German ground attack aircraft, such as the Henschel Hs 129. The KV-1s 76.2 mm gun also came in for criticism. While adequate against all German tanks, it was the same gun as carried by smaller, faster, and cheaper T-34 medium tanks. In 1943, it was determined that this gun could not easily penetrate the frontal armour of the new Tiger, the first German heavy tank, one of which was captured near Leningrad. The KV-1 was also much more difficult to manufacture and thus more expensive than the T-34. In short, its advantages no longer outweighed its drawbacks.

Nonetheless, because of its initial superior performance, the KV-1 was chosen as one of the few tanks to continue being built following the Soviet reorganization of tank production. Due to the new standardization, it shared a similar engine and gun as the T-34 (the KV used a 600 hp V-2K modification of the T-34s V-2 diesel engine, and had a ZiS-5 main gun while the T-34 had a similar F-34 main gun), was built in large quantities, and received frequent upgrades.

When production shifted to the Ural Mountains "Tankograd" complex, the KV-2 was dropped. While impressive on paper, it had been designed as a slow-moving bunker-buster. It was less useful in the highly mobile, fluid warfare that developed in World War II. The turret was so heavy it was difficult to traverse on uneven terrain. Finally, it was expensive to produce. Only about 300 KV-2s were made, all in 1940-41, making it one of the rarest Soviet tanks.

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 (German designation KV-1C), which had 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.

In response to criticisms, the lighter KV-1S was developed, with thinner armour and a smaller, lower turret in order to reclaim some speed. Importantly, the KV-1S had a commanders cupola with all-around vision blocks. It also had a sophisticated planetary transmission that significantly increased the reliability, and allowed use of more efficient regenerative geared steering, unlike the solely clutch and brake steering systems used by the Panzer III, IV and T-34 (and previous KV tanks). Its reduced weight allowed it to achieve a top speed of 43.3 km/h. Over 1,300 were built before production ended in August 1943. Although the KV-1S was, according to some, the best of the KV tanks, overcoming its predecessors problems (at a cost of losing the heavy armor that made the earlier tanks so valuable, making it more of slow medium tank than a heavy tank), more modern tanks were already in sight. Up-arming the regular turret of the KV-1S with an 85 mm S-31 resulted in the KV-1S-85. This was rejected as it came with the unacceptable loss of a dedicated commander, reducing the turret crew to two (unlike the 3-man turret fitted to the T-34/85). However, the thinning-out of the armour called into question why the tank was being produced at all, when the T-34 could seemingly do everything the KV could do and much more cheaply. The Soviet heavy tank program was close to cancellation in mid-1943.

The appearance of the German Panther tank in the summer of 1943 convinced the Red Army to make a serious upgrade of its tank force for the first time since 1941. Soviet tanks needed bigger guns to take on the growing numbers of Panthers and the few Tigers.

A stopgap upgrade to the KV series was the short-lived KV-85 or Objekt 239. This was a KV-1S with the new turret from the Object 237 (IS-85) still in development, mounting the same 85 mm D-5T gun as the SU-85 and early versions of the T-34-85 (not yet in production at the time). The 85 mm proved capable of penetrating the Tiger I from 1000 m and the demand for it slowed production of the KV-85 tremendously (only 148 were built in the end). The KV-85 appeared on the front beginning in September 1943 and its production ended by December 1943. Soviet industry was therefore able to produce a heavy tank as well armed as the Tiger I before the end of 1943. Although the KV-85 was an excellent opponent to the Tigers and Panthers, it was a stopgap and thus was built in small numbers. The complete Object 237 was accepted into service as the IS-85 and was produced in the autumn and winter of 1943-44; they were sent to the front as of October 1943 and production of the IS-85/IS-1 was stopped by the spring of 1944 once the IS-122/IS-2 entered full-scale production.

A new heavy tank design entered production late in 1943 based on the work done on the KV-13. Because Voroshilov had fallen out of political favour, the new heavy tank series was named the Iosif Stalin tank, after the Soviet leader Stalin. The KV-13 programs IS-85 prototype was accepted for production as the IS-1 (or IS-85, Object 237) heavy tank. After testing with both the 100 mm D-10 and 122 mm guns, the D-25T 122 mm gun was selected as the main armament of the new tank, primarily because of its ready availability and the effect of its large high-explosive shell when attacking German fortifications. The 122 mm D-25T used a separate shell and powder charge, resulting in a lower rate of fire and reduced ammunition capacity. While the 122 mm armour-piercing shell had a lower muzzle velocity than similar late German 7.5 cm and 8.8 cm guns, proving-ground tests established that the 122 mm could penetrate the frontal armour of the German Panther tank at 2500 metres and the HE shell would easily blow off the drive sprocket and tread of the heaviest German tank or self-propelled gun. The IS-122 replaced the IS-85, and began mass production as the IS-2. The 85 mm gun saw service in the lighter SU-85 and T-34-85.

The Soviets did not recognize different production models of KV-1 during the war; designations like model 1939 (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. All tanks in the series were heavily based on the KV-1.

A KV-1 or KV-2 tank (accounts vary) advanced far behind the German lines after attacking a column of German trucks. The tank stopped on a road across soft ground and was engaged by four 50 mm anti-tank guns of the 6th Panzer Divisions anti-tank battalion. The tank was hit multiple times by it but fired back, disabling all four guns. A heavy 88 mm gun of the German divisions anti-aircraft battalion was moved about 730 metres (800 yd) behind the tank, but was knocked out by the tank before it could score a hit. During the night, German combat engineers attempted to destroy the tank with satchel charges, but were unable to, despite possibly damaging the tracks. Early on the morning of 25 June, German tanks fired on the KV from the woodland while an 88 mm targeted the tank from its rear. Of several shots fired, only two penetrated the tank. German infantry then advanced, with the KV opening machine-gun fire against them. The tanks resistance was finally ended by grenades thrown into the tanks hatches. According to some accounts, the crew was buried by the German soldiers with full military honours; in other accounts, the crew escaped during the night.

General Erhard Raus was Commander of the 6th Panzer Divisions Kampfgruppe,[f] the unit delayed by the lone vehicle. He described it as a KV-1, which was damaged by several 88mm anti-tank gun shots fired from behind the vehicle while it was distracted by Panzer 35(t) tanks from Panzer Battalion 65, and the KV-1 crew were killed by members of a pioneer unit who pushed grenades through two holes made by the gun while the turret began moving again, the other five or six shots having not fully penetrated. Apparently, the KV-1 crew had remarkably only been stunned by the shots which had entered the turret. Afterwards, they were buried nearby with military honours by the German unit.[a]

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