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23 Jan 12,, 12:25
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T-34-76 Medium Tank – Introduction and Overview
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The T-34 Medium Tank is by far the most famous Soviet weapon of the Second World War, and has become a symbol of the Red Army’s desperate struggle against the Germans. In 1941 it was the most advanced tank then in mass production, and nearly 1,000 were present on the front line at the start of Operation Barbarossa, but like every other Soviet tank the T-34 was swept aside in the first phase of German victories. After this inauspicious start, the T-34 began to appear in ever larger numbers on the Eastern Front, and during the crucial battles around Stalingrad and at Kursk was almost the only tank in use with the Red Army.

Development
The T-34 emerged from three years of often confused development work, and was a very different vehicle to the one originally required in 1937.

A-20

In 1937 a large part of the Soviet tank force was made up of obsolete BT fast tanks. The high command of the Armoured and Motorized forces of the Red Army (ABTV or Avto-Bronetankovye Voyska) wanted to replace the BT tanks with a new fast tank, and on 15 August 1937 issued Resolution No.94. This called for a tank with wheel-and-track suspension, as used on the BT series, 20-25mm of armour, a 45-75mm gun and a 400hp Diesel engine.

This specification reached the No.183 Factory at Kharkov just as its design team was being reorganised. A new design bureau KB-24 was created, with twenty one engineers from Kharkov and forty six moved in from Moscow. M.I. Koshkin soon became chief designer for this new bureau, and would play a major part in the design of the T-34.

In October 1937 the new design team received the official specifications for the new fast tank. These were similar to those of August 1937, but did add a requirement for sloped armour. A series of three-way arguments about the design of the new tank followed, between the designers at Kharkov, the military and the Communist Party. The exact details of these arguments are now difficult to reconstruct, but the main focus appears to have been on the suspension. The wheel-and-track system used on the BT tanks allowed the tracks to be removed, turning the vehicle into an armoured car. This allowed it to move much faster on roads, and without damaging the unreliable tracks, but made the suspension much more complex. While the military still wanted this system, the tank designers were starting to see it as obsolete.

In March 1938 the Kharkov designers submitted the first design for what was then designated the BT-20. This carried 20mm sloped armour, would use the V-2 diesel engine, and had 4 pairs of road wheels.

On 4 May 1939 the Defence Committee met at the Kremlin, and gave KB-24 permission to design two prototypes of the A-20 – one with the track-and-wheels suspension, and one without. The designs were ready by February 1939, and on 27 February the Defence Committee approved the construction of both prototypes.

A-32

The A-32 evolved from the A-20 after the Kremlin meeting of May 1938. The Kharkov design team received permission to built a second prototype of the A-20, without the wheel-and-track suspension. This was originally designated the A-20G (Gusyenichnyi or tracked), but eventually became the A-32, reflecting the increased thickness of armour allowed by the removal of the wheel-and-track system.

A-20 vs A-32

Both prototypes were ready in May-June 1939. The A-20 began state trials on 15 July, the A-32 two days later. Both performed well, with the A-20 reaching a top speed of 85km/hr and the A-32 managing 70km/hr.

A-34

The success of the A-32 encouraged the creation of an even heavier version. In September 1939 the Defence Commissar agreed to the production of ten prototype A-32s with 45mm frontal armour. On 19 December, after the production of a new set of factory drawing, the Defence Committee approved the new design, and ordered the production of two prototypes.

T-34

T-34 Model 1940 in camouflage This order was drawn up as Resolution 443 of the Defence Committee, in which the new tank was referred to as the T-34. The new name is said to have been chosen to commemorate a 1934 decree announcing a massive expansion of the tank force.

The first prototype was completed on 16 January 1940, the second at the start of February. These two machines were produced to a very high standard, with precise measurements of every part, something that would not be a feature of the production tank. They were built using a significant number of imported parts, especially in key parts of the transmission, and would prove to be rather more reliable than the mass produced version. Later in 1940 representative of the Red Army would officially criticise this practice.

The two prototypes underwent factory and state tests at Kharkov, ending on 3 March 1940. The new tank was as agile as its designers had hoped, and was more mobile than the BT fast tanks. However some of the problems that would plague the T-34 were already clear – the sloped sides of the turret and the presence of the suspension springs inside the already narrow hull meant that the interior was very cramped, and visibility was poor, again partly because of the limited room for movement inside the vehicle. One of the V-2 diesel engines failed after 25 hours of operations.

The next stage of the trial was a drive to Moscow. The tanks left Kharkov on the night of 5-6 March, with Koshkin onboard one tank, and the crews provided by the design teams. After a journey that lasted ten days both tanks arrived in Moscow, where they were inspected by Stalin and the Politburo. The tanks were then sent on to the Kubinka proving grounds. One of the tests carried out here saw the second prototype subjected to four short range hits from a British 37mm anti-tank gun and a Soviet 45mm gun, without taking any significant damage.

Several months of discussion followed, before on 7 June 1940 the Council of Peoples Commissars (SNK) ordered No.183 Factory to prepare for mass production of the T-34. The military was well aware of the flaws of the T-34, and expected an improved version to be produced as quickly as possible (this work produced the T-34M, a rather better tank that never entered production).

Description
Suspension

The T-34 used a variant on the standard Christie suspension. In a normal Christie suspension system each wheel was mounted on an L-shaped bell crank. The wheel would be attached to the long end of the L, the crank would be attacked to the tank hull at the bend, and the short leg would be attached to a horizontally mounted spring. This system had two advantages – the sideways mounted springs could be made longer than vertically mounted springs, and the different length of the two sides of the crank turned a large amount of vertical movement into a much smaller horizontal movement.

On the T-34 all five road wheels were individually mounted, but the springs were all vertically mounted. Photographic evidence shows that the first road wheel used a slight modification of the Christie system, with the shorter branch of the bell crank located inside the tank, running back parallel to the longer wheel mounting, connecting to a strong spring. Despite the vertical mounting of the spring, this system did still produce the leverage effect of the bell crank, allowing a stiffer strong spring inside the tank to resist quite large movements of the front road wheel. The remaining four wheels used a rather more simple system. Behind each wheel there was a curved slot in the side of hull, with the suspension spring directly behind it. The wheel was mounted on a suspension arm that was connected to the tank by a strong axle just to the front of the wheel, and was also connected directly to the spring. The suspension arm forced any vertical movement of the wheel to follow a curved path, matching the gap in the side of the hull. The only element retained from the standard Christie suspension was that this system allowed the suspension springs to be mounted inside the tank.

V-2 Engine

The T-34 was powered by a V-2 diesel engine. This had a theoretical output of 500hp, but was normally used at 1700-1750rpm, and provided 400-450hp. At this power level the T-34 could achieve a top speed of 48km/hr (30mph). When carrying 460 litres of diesel the T-34 had a range of 188 miles on paved roads or 114 miles on dirt roads. For most of the war the V-2 engine had a lifespan of around 100 hours, well below the 150 hours factory guarantee. The quality fell after the German invasion forced the diesel plants to be evacuated to the east, while the engine cooling was unsatisfactory until 1943.

Work on the V-2 had begun at the Diesel Engines Plant – (KhDZ or Kharkovskiy Dizelniy Zavod). The factory was already involved in the production under licence of German diesel engines (production of these engines would only end in 1939), but in 1931 team of recent graduates under the leadership of K.F. Chelpan began to develop their own engine, the BD-2 (High Speed Diesel). Although the first prototype was ready in 1933, progress was slow, and even by 1937 no engine had run for more than 80 hours.

In April 1937 a team of experts from Moscow were sent to Kharkov to speed up the work, and by the summer of 1938 had produced a more reliable DB-2. In the spring of 1939 six prototype V-2s were ready, and each ran for 250 hours in tests. As with the T-34 itself these engines were far better made than the later production engines, but they did demonstrate that the basic design was good. The engine was put into production at the No.75 Factory in June 1940, just in time to be used in the T-34.

L-11 Gun

The original gun used in the T-34 was the 7.62cm L-11, with a length of 25 calibres. This gun had a muzzle velocity of only 555m/s, and by the standards of 1940 was badly underpowered. It was also an unreliable design.

F-34 Gun

A better gun was already under development. The KV-1 was armed with a longer 76.2mm gun, with a better muzzle velocity and thus better armour piercing capability. The same design team were then ordered to produce another new gun, possibly based of the F-22 L/41.6 divisional anti-tank gun, with testing to begin in September 1940. The new gun was tested in a BT-7 in October 1940, then in the second A-34 prototype. The Defence Committee then decided to put the new gun into production from 1 January 1941. The F-34 officially entered the Red Army arsenal in June 1941, although it was already being used in tanks by that date.

The F-34 was a 76.2mm L/41.2 gun, with a barrel length of 3m 16.9cm and a muzzle velocity of 680m/s. It could penetrate 92mm of vertical steel armour at 500 metres or 60mm at 1,000 metres, making it the equivalent of the American M3 75mm gun, and a little less effective than the German 7.5cm KwK 40 L/43.

The Turret

The small turret ring was the main limiting factor on the T-34. A desire to give the tank as small a frontal profile as possible produced a turret with steeply sloped sides that further reduced the amount of space inside. The one good feature of the turret was its MB-20 electric motor, which allowed the turret to make a complete revolution in just over 10 seconds. The two man turret greatly reduced the usefulness of the T-34, forcing the commander to act as his own gunner, and would be abandoned in the later T-34-85.

Visibility from the turret was poor. German tanks were equipped with a cupola that carried a series of periscopes, giving the commander all-round vision, while many tank commanders went into combat with their heads out of the turret, trading protection for visibility. In contrast on the T-34 the commander had a single moveable periscope with a narrow field of vision, and a view slit to his left (visible on the outside of the turret). This poor visibility helps explain why the T-34 often performed so badly in combat – the tank commander simply couldn’t see what his opponents were doing.

Armour

The most impressive feature of the T-34 was its thick sloped armour. At 45mm this was 15mm thicker than the armour of the Panzer IV Ausf D even before the slope is taken into account. Most comparisons of gun penetration assume an impact at 30 degrees, which would produce an angle of impact of 18 degrees against the frontal armour of the Panzer IV or 30 degrees against the T-34.

At these angles the Panzer IV armour had an effective thickness of 31 degrees, while the T-34 armour was effectively 51mm thick, while the 50mm armour of the Panzer IV Ausf F2 was effectively 52mm thick. The lower the angle of impact of the incoming shell, the more effective the T-34 armour while the Panzer armour became less effective. If hit by a shell travelling level with the ground the 45mm armour of the T-34 was effectively doubled. Only after the appearance of the Panzer IV Ausf G with 80mm of frontal armour were the two tanks on an equal footing.

The T-34 had been designed to use a one piece glacis plate, bent into shape by a massive press. Only the prototype definitely used this system, which was quickly abandoned for the mass production tank in favour of a three-part glacis. This had separate upper and lower glacis plates welded or riveted to a linking girder at the very front of the tank.

Combat Record
For most of the war the combat record of the T-34 is essentially that of the Red Army. In 1942 half of all Soviet tanks produced were T-34s, and that proportion rose to nearly 80% in 1943 and 86% in 1944. Here we will focus on the fighting in 1941, when the T-34 made up a much smaller proportion of the tank force, and its performance can thus be disentangled from the overall picture.

By June 1941 967 T-34s had been delivered to the front, 627 of them to the six mechanized corps of the Special Western Military District. There they would fight alongside 313 KV heavy tanks and a vast number of older BT series and T-26 tanks. Both of the new Soviet tanks technically outclassed the best the Germans had to offer in the summer of 1941, but there were serious problems to overcome before the Red Army had an effective tank force. Stalin’s purges had removed the vast majority of senior army officers. At every level the Red Army suffered from inexperienced officers, and from the presence of Stalin’s cronies in key positions.

Not only was the T-34 new in 1941, its crews were also often very inexperienced. Many were new conscripts from the spring class of 1941, with at best three or four hours of experience in the T-34. Many more experienced commanders had to carry out training after the fighting began! The units also lacked armour piercing shells, while the poor visibility from the two man T-34 turret reduced the accuracy when shells were available. The mechanised corps themselves had only just been recreated after having been abolished after the occupation of Poland in 1939. Early T-34s proved to be no more mechanically reliable than the older T-26 or BT tanks – all had an engine life of around 100 hours, although the T-34s did at least have the advantage of having newer engines closer to the start of their lifespan.

When the fighting began the Germans very quickly destroyed the first Soviet armies they encountered. The armies of the Special Western Military District were gone by 8 July 1941, after suffering catastrophic defeats around Bialystok and Minsk. The slow moving Soviet tank forces were often simply bypassed by the Panzers as they cut deep into Soviet territory, leaving the German infantry to have many of the early encounters with the T-34 and KV tanks. It is not always possible to disentangle the performance of the two new Soviet tanks. German reports of the period often refer to Soviet heavy tanks – the T-34 was significantly larger than the Panzer III or Panzer IV – while post-war memoirs tend to lump all Soviet tanks together as the T-34, hardly surprising after four years of fighting little else.

What can be said is that the standard 37mm anti-tank gun of the German infantry could not penetrate the armour of the T-34, but that the inexperienced gunners of the T-34 often had trouble hitting the German guns, and so ran them over instead! The German 88mm guns could cope with the T-34, but were in short supply in 1941. Mechanical unreliability played a major part in the Soviet disaster, accounting for about half of the total losses of the T-34.

When German and Soviet tanks did clash the T-34 posed a real problem to the Panzer troops. A direct hit from the F-34 gun could penetrate the frontal armour of both the Panzer III and Panzer IV, and the commander’s cupola was also reported to be very vulnerable. In contrast the short 5cm gun of the Panzer III was little more effective than the 37mm infantry gun, while the 75mm gun of the Panzer IV was designed to fire low velocity high explosive shells. Only after the appearance of the long 5cm gun in the Panzer III Ausf J did the Germans get a weapon capable of fighting the T-34 on equal terms, and this gun was responsible for half of all losses where the cause is known up to September 1942.

The T-34 demonstrated better than just about any other tank how little technical superiority can matter in armoured warfare. In 1941 the T-34 was better than the German tanks, and present in equal numbers to the German’s main battle tank of the time, the Panzer III, but the Soviets suffered massive losses. In 1943, at the battle of Kursk, the T-34 was present in vast numbers, but was outclassed by the Tiger I and by later versions of the Panzer IV, which by then could match it in armour and had a more effective gun. Despite that at Kursk it was the Germans who suffered a massive defeat. The Red Army had learnt how to turn its numerical advantage into hard won but decisive victories.

Comparisons
The quality of the T-34-76 is often overstated. During 1941 it had a real edge over the German tanks then in use, but mechanical unreliability let it down badly, while many early German combat reports often said to refer to the T-34 actually involved the KV series of heavy tanks. The Germans achieved their greatest victories in Russia during the very year in which the T-34 had its greatest advantage.

At the start of Operation Barbarossa the most modern German tanks were the Panzer III Ausf J and the Panzer IV Ausf F. Both were 8 tons lighter than the T-34, as well as being shorter and narrower than either German tank. Both the Panzer III and IV had 50mm frontal armour, thicker than on the T-34, but hardly sloped at all. The Panzer III had a two metre long 5cm gun, the Panzer IV a 1.8m long 7.5cm gun normally used to fire high explosive shells. Even the early L-11 gun in the T-34 was longer than either of these, and the F-34 was over three metres long. During the fighting in 1941 the T-34 was undoubtedly a better tank than anything available to the Germans.

In the summer of 1941 the Red Army had nearly as many T-34s and KV heavy tanks as the Germans had Panzer IIIs and IVs. Just under 1,000 T-34s had been delivered to the front line units, almost exactly matching the 960 Panzer IIIs used in Operation Barbarossa. The Germans had another 428 Panzer IVs, but these were not designed to fight other tanks, while the Soviets had 500 KV-1s and KV-2s. The key difference between the two sides was that the German tank forces were experienced, confident and well organised, and the Soviet tank forces were none of those things.

After 1941 the picture changes in favour of the Germans. With the appearance of the long-gunned Panzer IV Ausf F2 and StuG III Ausf F in the summer of 1942 the Germans gained armoured vehicles with the capacity to penetrate the armour of the T-34 at long range, and with the accuracy to hit their targets at those ranges. The T-34 was further outclassed after the appearance of the Tiger I in 1942 and the Panther in 1943. While the Germans produced ever more powerful tanks, the T-34-76 remained essentially the same after the installation of the F-34 gun in 1941.

This German technical superiority is reflected in the figures for tank losses. Most books on Soviet tanks mention the vast number of obsolete pre-war tanks destroyed during the fighting in 1941 – at least 20,000 were lost in the first six months of the war. With these older tanks out of the way, the Red Army was reequipped with newly produced tanks, most of which were T-34s. Despite this the heavy losses continued in 1942, when the Red Army lost around 15,000 tanks – six times the German total. Even through nearly 25,000 tanks were produced in the Soviet Union during 1942 in November 1942 just under 5,000 were available to the Red Army.

Those vast production figures were the key to the success of the T-34-76. In every year of the Second World War it represented at least half of all Soviet tank and armoured assault gun production. The peak for the T-34-76 came in 1943, when over 15,500 were produced from a total of just under 20,000 tanks and 4,000 assault guns. In 1942 and 1943 Soviet industry produced nearly three T-34s for every German tank produced!

Despite this impressive achievement 1942 was the only year in which the Soviet tank industry produced more tanks than were lost (24,000 produced, 15,000 lost), a figure at least partly explained by the production of over 9,000 light tanks. This figure helps explain why the various tanks developed to replace the T-34 never entered production – despite the image of vast Soviet hordes massively outnumbering the Germans, the Red Army was always operating on the edge of disaster. The reduction in production while switching from the T-34 to the T-34M or the T-43 might have been disastrous. The T-34-76 was eventually phased out in favour of the up-gunned T-34-85, with the switch coming during 1944, a move that could be made without much disruption on the production lines.

Conclusion
Although the T-34 was not the wonder-weapon of Soviet propaganda, it still deserves its place as one of the most famous weapons on the Second World War. When introduced it was the best medium tank design in the world, heavier, better armoured and better armed than anything the Germans had. Very little about the design was particularly innovative – the Japanese can claim the first mass produced diesel powered tank. Sloped armour was not new – the French FCM-36 infantry tank had it, as did a number of pre-war American designs. The T-34 can claim to be the first important mass produced tank to feature sloped armour. The long F-34 gun was the first to overhang the front of the tank by quite such an impressive margin, and triggered the start of a tank gun arms race on the Eastern Front that would leave the British and Americans some way behind by 1944.

Perhaps the main virtue of the T-34 was the speed with which it could eventually be produced. It played the same role on the Eastern Front as the M4 Sherman did in the west, using numbers to overwhelm the technically superior German tanks of 1942-45. The credit in this case should go less to the designers of the T-34 and more to the factory workers who produced tens of thousands of T-34s in primitive conditions east of the Urals and the tank crews who fought and died in such large numbers in the T-34.