Kliment Voroshilov tank

The Kliment Voroshilov (KV) tanks were a series of Soviet heavy tanks, named after the Soviet defense commissar and politician Kliment Voroshilov and used by the Red Army during World War II. The KV series were known for their extremely heavy armour protection during the early part of the war, especially during the first year of the German invasion of the Soviet Union.

They were almost completely 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 better guns were developed by the Germans it was often the case that the only way to defeat a KV was with a point-blank shot to the rear.

Prior to Operation Barbarossa (the German invasion of the USSR), about 500 of the over 22,000 tanks then in Soviet service were of the KV-1 type. When the KV-1 appeared, it outclassed the French Char B1, the only other heavy tank in operational service in the world at that time. Yet in the end it turned out 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. Later in the war, the KV series became a base for development of the IS (IS - Iosif Stalin) series of tanks.

Development history
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 armor on tanks, and was the main influence on Soviet tank design just prior to World War II.

The doctrine of Soviet deep battle called for the existence of relatively immobile, but heavily fortified, siege tanks that were supposed to keep pressure on enemy troops during the siege phase. Thus, the requirements for KV-1 were heavily skewed towards a potentially not-so agile, but heavy tank that was supposed to dominate the field.

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 the same combination of 76.2 mm and 45 mm weapons. 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 People's 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.

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 KV's heavy armour proved highly resistant to Finnish anti-tank weapons, making it more difficult to stop. In 1939 production of 50 KV 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 and Big turret, the 76-mm-armed tank was designated as the KV-1 Heavy Tank and the 152 mm howitzer one as KV-2 Heavy Artillery Tank.

The KV's strengths included armor 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 traction on soft ground. It also had serious flaws: it was difficult to steer, the transmission (which was a twenty year old Caterpillar design) was unreliable (and was known to have to be shifted with a hammer), and the ergonomics were poor, with limited visibility and no turret basket. 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 contemporary German tank. KVs were never equipped with a snorkeling system to ford shallow rivers, so they had to be left to travel to an adequate bridge. As applique armor 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 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."

While initially the Soviets made a lot of poor defense decisions, worsened by recent "cleansings" of Soviet military command, the KV-1 was unlike anything the German army had expected to encounter, and some of the battles against numerically superior Axis forces became legendary. Even though the operations of the KV family of tanks were severely hampered by restrictions due to its weight, it was a fearsome and formidable weapon through most of the Second World War.

Further development
By 1942, when the Germans were fielding large numbers of long-barrelled 50 mm and 75 mm guns, the KV's armor was no longer invincible. The KV-1's side, top, and turret armor could also be penetrated by the high-velocity MK 101 carried by German ground attack aircraft such as the Henschel Hs 129, requiring the installation of additional field-expedient appliqué armour. The KV-1's 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 penetrate the frontal armour of the new Tiger, the first German heavy tank, fortuitously 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 the similar engine (the KV used a 600 hp V-2K modification of the T-34's V-2 diesel engine) and gun (the KV had a ZiS-5 main gun, while the T-34 had a similar F-34 main gun) as the T-34, 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 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 rarer 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 released, with thinner armour and a smaller, lower turret in order to reclaim some speed. Importantly, the KV-1S also had a commander's cupola with all-around vision blocks, a first for a Soviet heavy tank. However, the thinning-out of the armor 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 a new turret designed for the IS-85, mounting the same 85 mm D-5T gun as the SU-85 and early versions of the T-34-85; demand for the gun slowed production of the KV-85 tremendously and only 148 were built before the KV design was replaced. The KV-85 was produced in the autumn and winter of 1943-44; they were sent to the front as of September 1943 and production of the KV-85 was stopped by the spring of 1944 once the IS-2 entered full scale production.

Successor
A new heavy tank design entered production late in 1943 based on the work done on the KV-13. Because Kliment Voroshilov had fallen out of political favour, the new heavy tank series was named the Iosif Stalin tank, after Iosif (Joseph) Stalin. The KV-13 program's IS-85 prototype was accepted for production as the IS-1 (or IS-85, Object 237) heavy tank. After testing with both 100 mm 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 122mm D-25T used a separate shell and powder charge, resulting in a lower rate of fire and reduced ammunition capacity. While the 122mm armour piercing shell had a lower muzzle velocity than similar late German 7.5 cm and 8.8 cm guns, proving-ground tests showed that the 122mm AP shell could defeat the frontal armour of the German Panther tank, 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.

Models
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.


 * KV-1
 * Model 1939 – First production models, these tanks were prone to frequent breakdowns, but were highly resistant 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 and F-32 gun.
 * 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. This tank was armed with the longer-barrelled F-34, and later ZiS-5 76.2 mm tank guns.
 * 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 thinner armour. A new, smaller, cast turret and redesigned rear hull were used. 1370 were built.
 * Panzerkampfwagen KV-IA 753(r) and Panzerkampfwagen KV-IB 755(r) - The KV-1 in German service. Some were fitted with a high-velocity KwK 40 L/43 75-mm gun, the same gun used in a Panzer IV Ausf F2.

All tanks in the series were heavily based on the KV-1 technology.


 * 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 than the KV-1. Those captured and used by the German Army were known as (Sturm)Panzer kampfwagen KV-II 754(r) and often used for artillery observation due to its height.
 * KV-3 (Object 223) - Experimental tank based on KV-1. Longer chassis (7 rollers per side). New 850 hp V-2SN engine. 120 mm armor. New conic turret. 107mm ZiS-6 cannon. One prototype was constructed and proved in 1941, and mass production was planned to begin the same year. The German invasion halted these plans.  Subsequently, the sole prototype was destroyed in battle against German heavy guns.
 * KV-4 (Object 224) - A project for a Super-heavy tank. About 20 different designs were proposed, but it was cancelled in favour of the IS series tanks. Different versions would have been between about 85 and 110 tonnes. Armour from about 120 to 150 mm. Armament 107mm ZiS-6 cannon. Different variants had various auxiliary weapons: 45mm, 76mm cannons, machineguns and flamethrowers in addition to their main gun.
 * KV-5 (Object 225) - A cancelled project for a heavy tank. Armament was to be a 107 mm ZiS-6 gun in a large turret and machine-gun in a small secondary turret. Project development began in June 1941, however was cancelled due to the Siege of Leningrad, when all developmental operations at the Kirov Plant were halted. The project fell out of favour from the more advanced heavy tank designs, and no prototype was built.
 * KV-6 (Object 226) - Experimental tank armed with a flamethrower next to the hull MG
 * KV-7 (Object 227) - Experimental selfpropelled gun armed with 3 cannons: two 45mm and one 76mm. One unit was produced and tested in 1941. KV-7-2 (improved variant) had two 76mm cannons. Vehicle was not taken in service.
 * 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 76.2mm gun was replaced with a smaller 45 mm Gun M1932, though it was disguised to look like the standard 76 mm (The cannon was placed inside 76mm tube).
 * KV-8S (25) – The same as KV-8, but based on KV-1S. Was equipped with ATO-42 flamethrower (improved version of ATO-41).
 * KV-8M - Upgraded version of KV-8S. Was equipped with two flamethrowers. Two prototypes was constructed.
 * KV-9 (Object 229) - A KV-1 with short 122mm U-11 cannon. One prototype was constructed and proved in 1941.
 * KV-10 (Object 230) - Also known as KV-1K. A KV-1 with 4 rocket launchers on the sides of hull. Each launcher contained two 132mm M-13 rockets. Early variant of KV-1K had 2 launchers on the back of hull, each contained 6 rockets. One prototype was constructed and tested in 1942. Not taken in service.
 * KV-11 (Object 231) - KV-1 armed with 85mm F-30 cannon. Projected in 1942. Not built.
 * KV-12 (Object 232) - Experimental chemical tank. Was equipped with 4 external toxin tanks on the back of chassis. Tanks surrounded with 30mm armor. Not taken in service.
 * KV-13 (Object 233) - Prototype of a medium tank. Designation for an advanced redesign of the KV series, which was resulted in the production of the IS series.
 * IS Model 2 - A KV-13, with turret and armanent from KV-9. One prototype was construcred and proved in 1943. Tank had lost competition to IS Model 1 and was not taken in service.
 * KV-14 (Object 236) – Prototype designation for a 152 mm self-propelled gun, accepted for service as the SU-152.
 * KV-85 – A KV-1S with the 85mm D-5T cannon in a new turret, with the ball mounted hull machine gun removed and the hole welded shut, 148 of these tanks were produced in the second half of 1943 until the spring of 1944 as a stopgap until the IS tank series entered production. This tank had its original turret, but later models were equipped with IS-1 turret.
 * KV-85G - KV-1S with 85mm S-31 cannon. Turret and mantlet remained from conventional KV-1S. This variant was a competitor of KV-85 during proving. It lost competition and was not taken in service.
 * KV-152 - A KV-1S with short 152mm S-41 cannon. One prototype was made in 1943. Not taken in service.
 * KV-100 - A KV-85 with the 100mm D-10T cannon. One prototype was made in 1944. Not taken in service.
 * KV-122 - A KV-85 with the 122mm D-25T cannon. One prototype was made in 1944. Not taken in service.
 * Т-150 (Object 150) - Experimental tank based on KV-1. Armor - 90mm. New 700 hp engine. Turret design and armament remained from KV-1. One prototype was constructed in 1941. Originally called the KV-3 but was renamed T-150 as to not be confused with the later KV-3.
 * KV-220 (Object 220) - Experimental tank based on KV-1. Longer chassis (7 rollers per side). Armor - 100mm. New 850 hp V-2SN engine with turbocharging. New diamond-shaped turret. 85mm F-30 cannon. One prototype was constructed in 1941, and was destroyed.
 * KV-222 (Object 222) - Experimental tank based on KV-1. Longer chassis (7 rollers per side). Armor - 90mm. New 850 hp V-2SN engine. Armament - 76mm F-32 cannon. One prototype was constructed in 1941, but wasn't destroyed.
 * U-18 - Experimental selfpropelled gun. KV-7 armed with 152 mm M-10 howitzer. Vehicle was projected in 1941. Wooden mockup was constructed. Project was cancelled, but this vehicle was a first step towards SU-152 design.
 * U-19 - Experimental selfpropelled gun armed with 203mm B-4 cannon. Not built.

Raseiniai


When Operation Barbarossa began, the Red Army was equipped with 508 new KV tanks. 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 88 mm anti-aircraft guns (flak) or 105 mm guns to knock them out. Only a few of these tanks were used to good effect, but one event of the Battle of Raseiniai was a notable example. On 23–24 June, a single KV-2 effectively pinned down elements of the 6th Panzer Division – the spearhead of Panzergruppe 4 – for a full day at the bridgeheads of the Dubysa river near Raseiniai, Lithuania, playing a prominent role in delaying the German advance on Leningrad and destroying around two dozen German tanks.

Krasnogvardeysk
On August 14, 1941, the vanguard of the German 8th Panzer Division approached Krasnogvardeysk (Gatchina) near Leningrad (now known again as Saint Petersburg), and the only Soviet force available at the time to attempt to stop the German advance consisted of five well-hidden KV-1 tanks, dug in within a grove at the edge of a swamp. KV-1 tank No. 864 was commanded by the leader of this small force, Lieutenant Zinoviy Kolobanov.

German forces attacked Krasnogvardeysk from three directions. Near Noviy Uchkhoz settlement the geography favoured the Soviet defenders as the only road in the region passed the swamp, and the defenders commanded this choke point from their hidden position. Lieutenant Kolobanov had carefully studied the situation and readied his detachment the day before. Each KV-1 tank carried twice the normal amount of ammunition, two-thirds of which were armour-piercing rounds. Kolobanov ordered his other commanders to hold their fire and await orders. He did not want to reveal the total force, so only one tank would expose itself at a time and engage the enemy.

On August 14, the German 8th Panzer Division's vanguard ventured directly into the well-prepared Soviet ambush. Kolobanov's tank knocked out the lead German tank with its first shot. The Germans falsely assumed that their lead tank had hit an anti-tank mine, and failed to realize that they had been ambushed. The German column stopped, giving Kolobanov the opportunity to destroy the second tank. Only then did the Germans realize they were under attack, but they failed to find the source of the shots. While the German tanks were firing blindly, Kolobanov knocked out the trailing German tank, thus boxing in the entire column.

Although the Germans correctly guessed the direction of fire, they could only spot Lieutenant Kolobanov's tank, and now attempted to engage an unseen enemy. German tanks moving off the road bogged down in the surrounding soft ground, becoming easy targets. Twenty-two German tanks and 2 towed artillery pieces fell victim to Kolobanov's tank before it ran out of ammunition. Kolobanov ordered in another KV-1, and 21 more German tanks were destroyed before the half-hour battle ended. A total of 43 German tanks were destroyed by just five Soviet KV-1s (two more remained in reserve).

After the battle, the crew of No. 865 counted a total of 135 hits on their tank, none of which had penetrated the armour. Lieutenant Kolobanov was awarded the Order of Lenin, while his driver Usov was awarded the Order of the Red Banner. Later on, former Captain Zinoviy Kolobanov was again decorated by Soviet authorities, despite having been convicted and downgraded after the Winter War for "fraternizing with the enemy." After the end of World War II, Lieutenant Kolobanov served in the Soviet occupation zone in East Germany, where he was convicted again when a subordinate escaped to the British occupation zone, and was transferred to the reserves.

The battle for Krasnogvardeysk was covered up by Soviet propaganda. A monument dedicated to this battle was installed in the village of Noviy Uchkhoz in 1980, at the place where Kolobanov's KV-1 was dug in, due solely to the demands of the villagers. Unfortunately it was impossible to find a KV-1 tank, so an IS-2 heavy tank was installed there instead.

The Soviet victory was the result of a well-planned ambush in advantageous ground and of technical superiority. Most of the German tanks in this battle were Panzer IIs, armed with 20 mm guns, and a few Panzer IIIs armed with 37 mm KwK 36 L/46.5 guns. The German tank guns had neither the range nor the power of the 76 mm main gun of a KV-1, and the narrower track width of the German tanks caused them to become trapped in the swampy ground.

Some KVs remained in service right up to the end of the war, although in greatly diminishing numbers as they wore out or were knocked out. The 260th Guards Heavy Breakthrough Tank Regiment, based on the Leningrad front, operated a number of 1941-vintage KV-1s at least as late as the summer of 1944 before re-equipping with IS-2s. A regiment of KVs saw service in Manchuria in August 1945, and a few KV-85s were used in the Crimea in the summer of 1944. The Finnish forces had two KVs, nicknamed Klimi, a Model 1940 and Model 1941, both of which received minor upgrades in their service, and both of which survived the war.