T-34-76
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modified: Nov 10, 2012
The T-34-76 (not to be confused with the light tank) was a Soviet medium tank that is considered to be the most successful Soviet tank from the Second World War. It is the second most-produced tank in history following the T-54/T-55 series. It was first produced at the KhPZ factory based on the BT series of tanks.

The performance of Soviet tanks during the Spanish Civil War demonstrated that their armor was inadequate. The T-26 infantry tank and BT-5 cavalry tank were easily penetrated by German 37mm anti-tank guns. Furthermore, during the Soviet engagement with the Japanese Army at Lake Khasan in 1938 and Khalkin Gol in 1939, the BT tanks were vulnerable to fires when their gasoline engines were ignited by artillery, mines, or infantry weapons.

By the end of 1937, there were three projects underway. Izdeliye 115 was started by the OKMO design bureau in Leningrad as a replacement for the T-28. The project called for a 32-tonne tank with up to 50mm of armor, a turreted 76mm gun and two sub-turrets with machine guns. The concept was outdated and the project was abandoned.

The second project was the T-46-5, also known as Izdeliye 111. Although a prototype was completed, it was not approved for mass production.


The third project was the A-20, a prototype intended to replace the BT tanks. It was developed by M. Koshkin's team at KhPZ. In addition to the A-20, a heavier version suggested by M. Koshkin, the A-32 (later designated T-32) was built. The A-32 had a frontal armor of 32mm and mounted a 76.2mm gun. Both prototypes were completed in July 1939 and sent to NIIBT for trials. The T-32 was accepted at meeting of the Defense Committee of the SNK held on December 19, 1939. It was decided that an up-armored version would replace the BT fast tank and T-28 medium tank. The new version was designated the T-34 (later also called the T-34-76 to differentiate it from the T-34-85). The name was chosen to commemorate the 1934 state decree expanding the Soviet armored force, the start of Sergei Ordhonikidze's leadership of tank production, and the year Koshkin began formulating his ideas about the new tank.

Two prototypes were built in January 1940. These tanks were driven from Kharkov to Moscow for a demonstration and then to Finland for trials along the Mannerheim Line. Although the prototypes arrived after the Russo-Finnish war ended, their firepower was tested on captured Finnish bunkers. Finally, the tanks were driven back to Kharkov through Minsk and Kiev.

As a result of the German-Soviet alliance of 1939, the Red Army received several PzKpfw III tanks. These tanks were sent to Kubinka for evaluation where the T-34 proved to be superior in armor, firepower, and mobility.

Although originally production was set at 200 tanks, this amount was increased to 600 tanks due to German advances in France and Soviet's poor conduct in Finland. 500 tanks were scheduled to be produced at KhPZ in Kharkov beginning in June 1940 and the rest at the Barrikady Tractor Plant in Stalingrad beginning in October. However, Marshal K. Kulik, the Deputy Peoples Commissar for Defense, insisted that changes be introduced on the T-34 citing reports from a special test-range that was set up and operated by his own personnel. As a result, only three T-34 Model 1940 tanks had been delivered to Red Army units by September 15, 1940. Later that month on September 26, M. Koshkin died of pneumonia after his health deteriorated due to the winter demonstration drive. His position was taken by the head of the conceptual design department, Aleksandr Morozov. In 1940, only 115 tanks were built some of which used the M-17T engine and the BT tank clutch because of V-2 engine shortages.


In 1941, a total of 2,800 T-34 tanks were scheduled for production with 1,800 coming from Kharkov and the rest from Stalingrad. In May of 1941, the Council of People's Commissars ordered an improvement program with the intent of building 500 of the improved type out of the 2,800 planned for production during 1941. The directive required replacing the Christie suspension, which used bulky springs that took up internal space, with the torsion bar suspension system which was used on the KV heavy tank and T-50 infantry tank. In addition, it called for an increase in the frontal armor from 45mm to 60mm, the side armor to 40mm, and the turret diameter to 1600mm. Furthermore, the program would also introduce a commander's cupola to the turret. This new version was designated T-34M by Morozov's design bureau. However, the T-34M project was later cancelled as tank factories shifted from improving the T-34 to simply maintaining production in the face of German advances in 1941.

Several small scale modification programs were already underway to improve the T-34. Morozov's design bureau focused on simplifying the T-34 so that it would be cheaper and easily manufactured by unskilled workers. In spring of 1941, V. Buslov and V. Nitsenko made a simplified 52mm cast turret as an alternative to the cold-rolled welded turret. The new turret entered production on a limited scale in the late spring of 1941. It was used on both T-34 Model 1940 and Model 1941 tanks. T-34s of STZ mainly had welded turrets while those built at Krasnoye Sormovo had cast turrets.

At this point, the designers were generally dissatisfied with the 76.2mm L-11 gun mounted on the T-34 Model 1940. Various armaments were considered as alternatives including the 57mm ZiS-4 anti-tank gun, and the old 45mm tank gun. The KV heavy tank was being equipped with the new 76.2mm F-32 gun which had better anti-armor performance due to its longer barrel. During the spring of 1940, P. Muraviev of Grabin's design team at Zavod Nr. 92 began work on adapting the F-32 to the T-34 turret. By the end of the year, the F-34 had been developed. However, neither the Main Artillery Directorate (GAU) under Kulik nor the GABTU would authorize the production of the new gun without official approval. Acting on their own initiative, Grabin and the plant director, A. Elyan, produced the F-34 alongside the L-11. The first F-34 guns were completed in January 1941, and unofficial T-34 Model 1941 tanks with the new gun began to appear in February 1941. This variant was primarily used by platoon and company commanders. The feedback received from these tank units was positive and encouraging. The GKO authorized the F-34 in the summer of 1941 and it was the standard main gun of the T-34 until 1944.

The T-34 was superior in firepower and mobility compared to the German PzKpfw III and PzKpfw IV tanks. Therefore, the Germans were forced to develop the new Panther tank and the 75mm PAK 40 anti-tank gun. The Panther didn't emerge on the battlefield until the summer of 1943.

When KhPZ No. 183 was evacuated to Nizhni Tagil, the GKB-T-34 (T-34 Main Design Bureau) was also moved. The first tank from the new plant, now called Uralvagon Plant No. 183, was not ready until December 20, 1941. To compensate for the delay caused by the evacuation of the Kharkov plant, the Krasnoye Sormovo Zavod No. 112 in Gorkii was ordered to begin preparing for T-34 production in July 1941. The first tanks were delivered to the Moscow Front in November 1941. Plant No. 174 in Omsk was also switched to the manufacture of T-34 components.

A total of 1,121 T-34s were built in the third quarter of 1941 while the figure for the fourth quarter was 765. Shortages of V-2 diesel engines led to some tanks being manufactured with the M-17 gasoline engine, and others received the shorter 76.2mm F-32 gun due to the lack of the standard F-34 gun.

T-34 Model 1942
There were several disadvantages that affected the T-34's combat performance including the lack of radios and a cramped two-man turret. Issues that were frequently cited in after-action reports were the unreliability of the clutch/gearbox, the vulnerability of the driver's front hatch to enemy fire, and the vulnerability of the hull side armor. The smooth plate tracks provided poor traction in muddy conditions, and they were prone to breaking under enemy fire.

At the end of 1941, the design bureau developed the new T-34 Model 1942. Although it is similar to the earlier version in appearance, many simplifications were made. For instance, the F-34 Model 1941 gun had 861 parts while Model 1942 had 614. In addition, the cost of a T-34 was lowered from 269,500 rubles in 1941 to 193,000 rubles in 1942. The production time was also cut in half but at the expense of the quality of craftsmanship. Many of the hull fittings were simplified and some features, such as a second roof periscope for the loader, were removed.

Additional improvements were also made as a result of combat experience. The hull side armor was increased from 40mm to 45mm. The driver's hatch was redesigned. The rectangular transmission access hatch on the rear plate was replaced by a circular hatch. The engine grill-work was simplified. A new, wider 500mm track with a waffle pattern cast on the front improved traction.

There were variations in the detail of the T-34 produced at different plants. For example, the T-34 Model 1941 built at the STZ plant in Stalingrad featured a glacis plate which interlocked with the side hull plates, and the rear turret panel was a larger, separate item. The STZ plant did not immediately adopt all the changes of the T-34 Model 1942, producing tanks with some features of the earlier Model 1941 such as the rear access hatch. This intermediate version is called T-34 Model 41/42. The Barrikady Plant in Stalingrad which manufactured the guns for the STZ simplified the gun housing, giving it a chisel-nosed appearance. The Stalingrad Ship Plant, which built the turrets, modified the cold-rolled, welded turret in 1942 by chopping off the lower corner of the turret front, another distinctive feature of the later STZ-produced tanks. The cold rolling presses used at Kharkov were temporarily lost when the plant was moved to Nizhni Tagil. Therefore, the first Uralvagon T-34s used a new cast turret developed by M. Nabutovskiy. The Krasnoye Sormovo plant used a cast turret with a slightly different shape and thicker armor, about 60mm vs 52mm compared to the Uralvagon plant.

In 1942, there was a lack of rubber at Soviet tank plants. Therefore, all factories switched to all-steel roadwheels for the T-34. However, when the tanks were traveling at high speeds, a harmonic vibration was created which was unpleasant for the crew and loosened parts. To mitigate this problem, rubber-rimmed wheels were used for the first and fifth road wheel positions. By 1943, the all-steel wheel had disappeared completely.


In August 1942, production of the T-34 was spread to Tankograd and it continued until April 1944. The Stalingrad plant continued tank production until September 1942 as fighting was taking place in the outskirts of the city. Up to that point, the Stalingrad Tractor Plant accounted for about 42% of all T-34s built. Furthermore, the Ural Heavy Machine Tool Factory (UZTM, Uralmash) in Sverdlovsk which had been producing T-34 hulls and turrets, focused solely on assembly of the T-34 from October 1942.

T-34 Model 1943
A new version, the T-34 Model 1943 was manufactured at Nizhni Tagil starting in early 1942. It had a larger hexagonal cast turret, an offshoot of the T-34 program. This turret was larger and more spacious than the early type, with 70mm frontal armor and 52mm side armor. Ammunition stowage was increased from 77 rounds to 100 rounds.

The new turrets were generally manufactured by casting, with a rolled-plate roof. However, those produced at Uralmash with a special 5,000 ton forge had a distinctly rounder appearance. A total of 2,670 drop-forged turrets were manufactured, and they were used on tanks assembled at Tankograd in Chelyabinsk and at Uralmash in Sverdlovsk. Not all turret producers switched to the new hexagonal turret. One of the plants supplying Krasnoye Sormovo continued to manufacture the smaller Model 1942 type until the end of 1942, and both turret types were mounted on hulls concurrently. The T-34 Model 1943 was first seen in Karelia in April 1942 against Finland.

Additional improvements included a new 'Tsiklon' air filter, and a new five-speed gearbox. By the summer of 1942, a new style of 40 liter external fuel box was manufactured for the T-34 in at least two patterns, and mounted in pairs on the rear plate. In early 1943, a new style of external fuel stowage was adopted, using three circular drums on the hull side. These containers did not directly feed into the tank's fuel system. The crew used a small electrical pump or a hand pump to transfer fuel into the internal fuel cells. New tracks for muddy and snowy terrains were also developed.



Towards the end of 1943, the T-34 Model 1943 was redesigned to offer a circular commander's cupola on the turret roof with a 360° vision. Most new tanks were also equipped with radios.

The T-34 remained in service until the end of the Second World War but it was increasingly replaced with the T-34-85. Peak production for the T-34-76 occurred in 1943, with 15,712 manufactured. T-34-76 production in 1944 was only 3,723. Total T-34-76 production was 35,120. After the war, remaining T-34-76 tanks were scrapped or converted to recovery vehicles. No T-34-76 tank is known to have participated in combat after 1945.

Description
Like the KV, the T-34 did not have a turret basket and the crew was seated on stools suspended from the turret ring. Behind the engine firewall was the V-2 diesel engine with cooling radiators on either side, a cooling fan in the center, and the transmission at the rear. Fuel was stored in cells located in the angled portions of the hull side. Since the transmission was placed at the rear of the vehicle, the fighting compartment was not burdened by a drive train running to the front of the tank. This allowed the T-34 to have a low overall height.

The hull of the basic T-34 Model 1942 was constructed using homogenous rolled steel armor plate. The 45mm glacis plate has a Brinell hardness of 354 to 400. The early T-34 Model 1940 tanks were built to a standard on par with western European or American designs. However, in the middle of the Second World War, the workmanship had declined, though the plant inspectors ensured that combat performance was not sacrificed.

The glacis plate, although 45mm thick, had an effective thickness of 75mm because it was highly sloped. The turret front was also extremely sloped. Some Soviet units added appliqué armor to counter upgrades of German tanks and anti-tank guns. However, this was not adopted as a standard feature because it would have burdened the powerplant and suspension.

The T-34 had a crew of four: a driver/mechanic in the left front of the hull, a machine gun/radio operator in the right front hull, a commander/gun aimer in the left side of the turret, and a loader in the right side of the turret. The driver was provided with a large hatch in front of his station. Access to the turret was through a one piece hatch that hinged forward. There was a signle escape hatch in the floor of the vehicle, under the machine gunner's station. A set of conventional tractor-style brake levers were used to steer the tank. A pair of compressed air bottles were used to help start the engine in cold weather.

At the beginning of the Great Patriotic War, company commanders' tanks were almost always provided with a 71-TK-3 transmitter/receiver. Efforts were also made to equip platoon commanders' tanks with radios. In 1941 and 1942, the 71-TK-1 was sometimes used. Later in 1942, the 9-R radio was introduced. Communication inside the tank was by means of a TPU-3 intercom system. The crew's cloth helmet contained earphones and a throat mike.

Due to the lack of radios, Soviet tankers relied on a set of rehearsed flag signals. There was a special hatch in the main turret to allow commanders to signal.

The tank gun was aimed using a TOD-6 telescopic sight on the earlier tanks and TMFD on later production types. The telescope was 2.5x magnification and had illuminated graticules. For general viewing, the tank was equipped with a PT-6 panoramic periscopic sight on the early version, and a PT-4-7 or PT-5 on the later vehicles such as the T-34 Model 1942. Although both the commander and loader were initially provided with sights, many tanks had only a single periscopic sight due to wartime shortages. The sight could be linked to the gun as an alternative to the telescopic sight.

Both the commander and loader were provided with an armored glass viewing port. Pistol ports were located under the viewing ports, as well as one on the turret rear.

The Soviet commander did not have a 360° vision cupola like his German counterpart. Furthermore, it was dangerous for the commander to ride with his head outside of the tank because the large turret hatch pivoted forward, obstructing his view. When the large hatch was open, it exposed not only the commander, but the loader as well. The Germans exploited dead-zones where the T-34's crew could not see them to place satchel charges and other anti-tank devices.

While German tank turrets were manned with three men: gunner, loader, and commander, Soviet T-34 turrets only had a loader and commander. In addition to observing the terrain, searching for targets, directing his crew, and coordinating with other tanks, the commander also aimed the main gun. The two-man turret crew severely hampered the T-34's battlefield performance. Some Soviet units experimented with substituting the commander as the loader instead of the gunner, but this approach did not remedy the problem.

The hexagonal turret on the T-34 Model 1943 had split hatches, but both opened forward. A commander's cupola with a 360° vision was added to the T-34 Model 1943. A three-man turret did not appear until the T-34-85.

The loader is responsible for loadng the main gun and the DT coaxial machine gun. The T-34 Model 1942 carried 77 rounds of 76.2mm ammunition. This was increased to 100 rounds on the T-34 Model 1943. Three ready rounds were placed on the hull side near the loader's feet, and six more rounds on the opposite wall near the commander. The other 68 rounds were stowed in eight metal bins on the floor of the fighting compartment. The standard combat load was 19 rounds of BR-350A armor piercing, 53 rounds of F-354 or OF-350 high explosive and five rounds of shrapnel. By the spring of 1943, the new BR-350P APDS round was introduced. The ammunition bins were covered with a neoprene mat and the loader would have to pull the cover back to gain access to the ammunition. The floor of the turret becomes disorganized during battle when ammunition was removed.

The 7.62mm ammunition for the coaxial and bow machine guns was stowed in 35 drums with 65 rounds each. About half of the drums were stored in racks at the rear of the turret, while the remainder were located in various racks in the forward portion of the fighting compartment.

The T-34 was initially armed with the 7.62mm L-11 rifled gun with a length of 30.5 calibers. It was later replaced with the 42 caliber 76.2mm F-34 gun, the predominant type. Some tanks were fitted with the 39 caliber 76.2mm F-32 which operated in the same fashion as the F-34. The F-34 used a conventional semi-automatic drop breech. It was ballistically similar to the 76.2mm ZiS-3 divisional gun, but used a different recoil system with a hydraulic buffer and hydro-pneumatic recuperator under the gun tube.

The F-34 gun had an elevation of -3° to +30°. The earlier L-11 gun had greater depression, down to -5°, while the F-32 had restricted elevation of +28° when mounted. Turret traverse was provided on the commander's side of the turret, with both a manual handwheel or an electric traverse which turned the turret at 26° per second. There was considerable play and backlash in the traverse gearing which made precise aiming of the gun difficult at longer ranges. The commander could fire the main gun using a pedal.



References: OW, STCV, T34MT, TMT