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date of publication: 09-02-2013

Heavy Tank IS-2 IS-3


Heavy Soviet Tank IS-2

The need for a larger gun for the had in fa ct been identified by Kotin's team and designers at Zavod Nr 9 in the wake of the Battle of Kursk in July 1943. This realization had two effects. First, production of the IS-1 with an 85mm (3.34 in) gun was restricted until it could be equipped with a more powerful gun. Second, the 100mm (3.93 in) BS-3 and 122mm (4.8 in) A-19 guns were adapted for the IS-1 and put through firing tests during November 1943.

The smaller gun proved to have the more effective armour penetration, although the larger one showed its potency by ripping the frontal armour off a captured Panther. Ultimately the 122mm (4.8 in) gun was selected because there was a surplus of manufacturing resources for the gun and its ammunition, whilst the 100mm (3.93 in) was in short supply. The barrel was initially fitted with a single chamber muzzle brake, but th is was changed to two chambers after one of the guns exploded during testing and narrowly avoided fatally wounding Marshal K. E.Voroshilov.

Not content with up-gunning the IS-1 design, Kotin developed the IS-2 with improved armour and mobility. The stepped armour glacis plate of the earlier design was replaced by a flat sloping type, giving better protection, bur avoiding the need for thicker armour that would increase the vehicle's weight. The new hull could withstand a direct shot from a German 8.8 cm (3.46 in) armour-piercing round at over 1000m (9144 yd), whilst its own gun could penetrate 160mm (6.29 in) of armour at the same range, if its gunners could hit the target. Attempts to improve the turret's protection had to be cancelled because the weight of the 122mm (4.8 in) gun would have made it unbalanced. The possibil ity of re-designing the turret was turned down because of the cost and a lack of time.

Soviet Heavy Tank IS-2M - Model 1944

In reality, the IS-2 had several major shortcomings. The designers were aware that the IS-2's effectiveness in combat was restricted by a slow rate of fire (just 2 or 3 rounds per minute) and stowage room for only 28 rounds. The former factor was partially solved in 1944, when an improved D-25T gun was introduced with a more efficient breech. Combat experience also revealed that the 122mm (4.8 in) gun could not penetrate the Panther's sloped armour above 600m (656 yd), whilst splintering remained a problem for the IS-2's own armour. Tempering the frontal armour to very strong hardness proved too complex and costly to in troduce, and the deficiency was allowed to remain. Ironically, in late 1944 the difficulty in dealing with the Panther was partially, though unintentionally, solved by the Germans. Shortage of manganese led to a switch to using high-carbon steel alloyed with nickel for armour plate, which made it more brittle, in particular along weld seams.


Heavy Tank IS-2

The IS-2 was issued to Guards Heavy Tank Regiments from the start of 1944. The first unit equipped wirh them to see action was the 11th Guards Independent Brigade in April in operations in the southern Ukraine, following the successful encirclement and destruction of German forces in the Korsun-Shevchenkiovsky area. In 20 days of fighting, the 72nd Independent Guards Tank Regiment lost only eight IS-2s, whilst inflicting great loss on the enemy, although claims of 41 Tigers and Elephants is excessive and probably the result of mistaken identity. During this period of action, one IS-2 tank withstood five direct hits from the 8.8 cm (3.46 in) gun of an Elephant fired from 1500-2000mm (1640-2187 yd). The vehicle was eventually knocked out by another of these vehicles at 700m (765 yd). The loss of other vehicles to fire and engine damage serves to highlight the point that even the most heavily armoured tank still has areas of vulnerability.

One of the IS-2's most notable engagements took place during the fighting in August 1944 to establish a bridgehead across the river Vistula around the town of Sandomierz. This was the first rime that the IS-2 had come up against the fearsome' Royal Tiger. During the engagement on 13 August, the 71st Independent Heavy Tank Regiment's 11 IS-2 blocked an attack by 14 Royal Tigers of the 501st Heavy Panzer Regiment. Engaging at 600m (656 yd) coupled with skilled tactical handling saw four Royal Tigers destroyed and seven damaged, for the loss of three IS-2s and seven damaged. This was a very creditable performance, although post-barth analysis again revealed that the IS-2's armour was vulnerable up to 1000m (9144 yd) because of faulty casting.


Soviet Heavy Tank IS-3

Continued analysis of the combat performance of tanks, in particular the location and type of damage inflicted on them, led to the development of the IS-3 tank. This was to be the last Soviet produced during the war. The vehicle's design was drawn from ideas which were developed by two separate teams.

One under Katin developed an unusual frontal armour glacis. This consisted of two plates welded together at an angle, sloping down to the vehicle's from, termed a Pike nose by its creators. The design reduced the tank's weight but, it was hoped, increased the strength of the hull and its resistance to enemy fire. The other team under N. L. Dukhov developed a radical rounded-bowl shaped turret, housing a 122mm (4.8 in) gun. This radical shape increased protection by deflecting the kinetic energy of incoming shells, whilst improving the internal layout of the turret and consequently the tank's fighting efficiency.

Soviet Heavy Tank IS-3 1944

The decision to combine the two teams novel ideas into a single model was taken by the Minister of Tank Industry, V. A. Malyshev. The first prototype was shown to Marshals S. K. Zhukov and A. M. Vasilevsky in October 1944, and received a strong recommendation for production. The first production models appeared in the early months of 1945, and it is reported that some saw action towards the end of the fighting in Berlin. Production of the vehicle was continued until mid-1946, by which time a tOtal of 2311 tanks had been produced.

The IS-3 continued in service with Red Army front-line forces until as late as the 1960s. During this time it underwent a series of modifications in order to remedy serious design faults; unreliable engine and gearbox, and a defective hull in areas. However, these modifications proved only a partial success, and by this stage, Soviet tank design and doctrine was focusing on the medium tank as the main armoured vehicle which would be the most effective during every stage of the deep battle and deep operation.


Heavy Tank IS-3

Throughout World War II, Soviet tank designers repeatedly demonstrated their creativity and pragmatism. Consistently they made maximum use of their limited resources by asking if a specific design was adequate for the task required, rather than squandering extra time and resources - as their German counterparts did - on creating totally new components, or striving for total perfection and accepting only the best. This meant that Soviet tanks lacked the exterior and interior refinements of German and western vehicles, but as the bottom line was how the vehicle performed during operations, these shortcomings were acceptable. As a result, the British and American designs lagged behind those of throughout the war in what they could achieve on the battlefield. The whole Soviet approach to war was Slimmed up by a British Army platoon sergeant called John Erickson (later a Professor of Modern History and one of the leading pioneers in research on the history of the ) who commenced on a Red Army parade in Berlin after the war was finally over:

an army of unwashed, uncouth little Ukrainians, squat riflemen from the Central Asian Republics, combat medals a-jingle, cradling superb self-loading rifles - but above all, the tanks in their fungal green colouring, the paint just slapped over those powerful turreted guns. It was also an army that won.