T-26
The T-26 tank was a Soviet light tank used during many conflicts of the Interwar period and in World War II. It was a development of the British Vickers 6-Ton tank and was one of the most successful tank designs of the 1930s until its light armour became vulnerable to newer anti-tank guns. It was produced in greater numbers than any other tank of the period, with more than 11,000 units manufactured, giving it the title of the most produced tank during the interwar period. During the 1930s, the USSR developed 53 variants of the T-26, including flame-throwing tanks, combat engineer vehicles, remotely controlled tanks, self-propelled guns, artillery tractors, and armoured carriers. Twenty-three of these were series-produced; others were experimental models.
The T-26 and BT were the main tanks of the Red Army's armoured forces during the interwar period. The T-26 was the most important tank of the Spanish Civil War and played a significant role during the Battle of Lake Khasan in 1938, as well as in the Winter War in 1939–40. Though nearly obsolete by the beginning of World War II, the T-26 was the most numerous tank in the Red Army's armoured force during the German invasion of the Soviet Union in June 1941. The T-26 fought the Germans and their allies during the Battle of Moscow in 1941–42, the Battle of Stalingrad and the Battle of the Caucasus in 1942–1943; some tank units of the Leningrad Front used their T-26s until 1944. Soviet T-26 light tanks last saw use in August 1945, during the defeat of the Japanese Kwantung Army in Manchuria.
The T-26 was exported and used extensively by Spain, China and Turkey. Captured T-26s were used by the Finnish, German, Romanian and Hungarian armies. The tank was reliable and simple to maintain, and its design was continually modernised between 1931 and 1941. No new models of the T-26 were developed after 1940.
British origin
The T-26 was a development of the British Vickers 6-Ton tank, which was designed by the Vickers-Armstrongs company in 1928–29. The simple and easy-to-maintain Vickers 6-Ton was intended for export to less technically advanced countries: the Soviet Union, Poland, Brazil, Argentina, Japan, Thailand, China, and many others. Vickers advertised the tank in military publications, and both the Soviet Union and Poland expressed interest in the Vickers design.In early 1930, the Soviet buying committee, under the direction of Semyon Ginzburg, arrived in the UK to select tanks, tractors, and cars for use in the Red Army. The Vickers 6-Ton was among four tank models selected by Soviet representatives during their visit to Vickers-Armstrongs. Under the contract signed on 28 May 1930, the company delivered to the USSR 15 twin-turreted Vickers Mk.E tanks together with full technical documentation to enable series production of the tank in the USSR. The ability of the two turrets of the Type A to turn independently made it possible to fire to both the left and right at once, which was considered advantageous for breakthroughs of field entrenchments. Several Soviet engineers participated in assembly of the tanks at the Vickers factory in 1930.
The first four Vickers 6-Ton tanks arrived in the USSR at the end of 1930. The last tanks arrived in 1932, when series production of the T-26 was already in progress. The British tanks were sent to Soviet factories for study in preparation for series production and to military educational institutions and training units. Later, some tanks were given to military supply depots and proving grounds. The Vickers-built 6-Ton tanks were called V-26 in the USSR. Three British tanks were tested for cross-country ability at the small proving ground near Moscow on Poklonnaya Hill in January 1931. Kliment Voroshilov ordered the creation of the "Special Commission for the Red Army new tanks" under the direction of S. Ginzburg to define the tank type suitable for the Red Army. The T-19 8-ton light infantry tank, developed by S. Ginzburg under that programme at the Bolshevik Plant in Leningrad, was a competitor to the British Vickers 6-Ton. The first prototype of the complex and expensive T-19 was finished in August 1931. Because both tanks had advantages and disadvantages, S. Ginzburg suggested developing a more powerful, hybrid tank with the hull, home-developed engine and armament from the native T-19, and the transmission and chassis from the British Vickers 6-Ton.
On 26 January 1931, I. Khalepsky, Head of the Department of Mechanisation and Motorisation of the RKKA, wrote a letter to S. Ginzburg with information obtained via the intelligence service that the Polish government had decided to purchase Vickers 6-Ton light infantry tanks as well as Christie M1931 cavalry tanks and to mass-produce them with the assistance of both the British and French. Because Poland was then considered, in Soviet military doctrine, to be the USSR's main enemy, the Soviet Revolutionary Military Council decided to pass the foreign tanks into Red Army service, starting their production immediately without waiting for the completion of development works, in order to counter possible aggression. At that time, the RKKA had only several dozen outdated Mark V heavy tanks and Medium Mk.A and Renault FT tanks, captured during the Russian Civil War, together with various armoured cars and obsolescent domestic MS-1 light infantry tanks. On 13 February 1931, the Vickers 6-Ton light infantry tank, under the designator T-26, officially entered service in the Red Army as the "main tank for close support of combined arms units and tank units of High Command Reserve".
One of the Vickers 6-Ton tanks was tested for gunfire resistance in August 1931. The hull was subjected to rifle and Maxim machine gun fire with the use of normal and armour-piercing bullets at a range of. It was found that the armour withstood gunfire with minimal damage. Chemical analysis showed that the front armour plates were made from high-quality cemented armour, whereas the homogenous roof and bottom armour plates were made from mediocre steel. Even so, the British armour was better than armour produced by Izhora Factory for the first T-26s because of a shortage of modern metallurgical equipment in the USSR at that time.
At the same time, the Faculty of Mechanisation and Motorisation of the Military Technical Academy named after F.E. Dzerzhinsky developed two tank models based on the Vickers 6-Ton tank design but with an American Hercules six-cylinder water-cooled engine, improved front armour, and a driver's position on the left side. TMM stands for tank maloy moshchnosti or "tank of low power". The TMM-1 was equipped with transmission details from the native and a ball mount for the DT tank machine gun in front of the hull, whereas the TMM-2 was equipped with an improved gearbox, a clutchless steering device and a 37 mm Hotchkiss gun in the right turret. Representatives from the main Soviet tank manufacturers together with officials from the RKKA Mobilization Department considered the Hercules engine to be too difficult to produce, and the engine tended to overheat inside the engine compartment. Tests of TMM-1 and TMM-2 prototypes performed in the beginning of 1932 demonstrated no advantage over the Vickers 6-Ton and the T-26.
Design
The Soviets did not simply replicate the Vickers 6-Ton. However, like its British counterpart, the T-26 mod. 1931 had a twin-turreted configuration and was designed to carry two machine guns, mounting one in each turret. A major difference was that the Soviet T-26 mod. 1931 had higher turrets than the British 6-Ton. Soviet turrets had a round firing port for the Degtyarev light machine gun, as opposed to the rectangular ports used by the original British design for the Vickers machine gun. The front part of the hull was also slightly modified.Hulls of twin-turreted T-26s were assembled using armoured plates riveted to a frame from metal angles. Some tanks, produced in 1931, had sealing zinc shims at the hull bottom between armoured plates for fording water obstacles. After problems with rain entering the engine compartment, a special cover was installed over an air outlet window after March 1932. Some T-26s produced at the end of 1932–1933 had a riveted and welded hull. The T-26 mod. 1931 had two cylindrical turrets mounted on ball bearings; each turret turned independently through 240°. Both turrets could provide common fire in front and rear arcs of fire. The disadvantage of such a configuration was that not all of the tank's firepower could be used at once on the same side. Four turret modifications existed, and they were mounted on tanks in different combinations.
The hull and turrets of the T-26 mod. 1931 had a maximum armour thickness of 13–15 mm, which was sufficient to withstand light machine gun fire. Many twin-turreted tanks of the first series had 10 mm armour plates of low quality, which could be penetrated by 7.62 mm armour-piercing bullets from
In 1933, the Soviets unveiled the T-26 mod. 1933. This model, which had a new single cylindrical turret carrying one 45-mm cannon L/46 and one 7.62 mm machine gun, became the most common T-26 variant. The 45 mm 20K tank gun was based on the Soviet 45 mm anti-tank gun M1932 and it was one of the most powerful anti-tank guns of its time. The T-26 could carry up to three secondary DT 7.62 mm machine guns in coaxial, rear, and anti-aircraft mounts. This increased firepower was intended to aid crews in defeating dedicated anti-tank teams, as the original machine gun armament had been found insufficient. The turret rear ball mounting for the additional DT tank machine gun was installed on the T-26 tanks from the end of 1935 until 1939.
The T-26 Model 1933 carried 122 rounds of 45 mm ammunition, firing armour-piercing 45 mm rounds with a muzzle velocity of, or lower-velocity high-explosive munitions. Tanks intended for company commanders were equipped with a radio set and a hand-rail radio antenna on the turret. Later the hand-rail antenna was replaced with a whip antenna, because experience in the Spanish Civil War and Battle of Lake Khasan showed that the hand-rail antenna drew fire onto commander tanks.
The tank was powered by a GAZ T-26 straight 4-cylinder air-cooled petrol engine, which was a complete Soviet copy of the Armstrong Siddeley engine used in the Vickers 6-Ton. The engine was located in the rear part of the hull. Early Soviet-made tank engines were of bad quality but they became better beginning in 1934. The engine did not have an over-speed limiter, which often resulted in overheating and engine valve breakage, especially in summer. A fuel tank for and an oil box for were placed alongside the engine. The engine required top-grade petrol; the use of second-rate petrol could cause damage to the valve units because of engine detonation. From mid-1932, a more capacious fuel tank – instead of – and a simplified oil box were introduced. An engine cooling fan was mounted over the engine in a special shroud. From early 1932, the exhaust silencer was affixed by three clamps instead of two.
The transmission of the T-26 consisted of single-disc main dry clutch connected to a gearbox, with five gears, in the front part of the vehicle by drive shaft passing through the vehicle. Steering was through steering clutches and band brakes. The gear change lever was mounted directly on the gearbox.
Suspension consisted of two bogies, four rubber-covered return rollers, a track driving wheel and a track idler. Each bogie consisted of a cast box with four twin rubber-covered road wheels connected by balancing levers and two one-quarter elliptic leaf springs. The cast track driving wheel with removable sprocket ring was located in front, and the track idler with a crank lever tightener was located at the rear of the vehicle. The track was made from chrome-nickel steel wide and consisted of 108–109 links.
The T-26 mod. 1931 did not have a radio set. The tank commander communicated with the driver by speaking tube, which was replaced with a signalling lamp in 1932. The T-26 was equipped with a fire extinguisher, a kit of spare parts tools and accessories, canvas stowage, and a tow chain fixed on the rear of the hull.
The T-26 could cross -high vertical obstacles and -wide trenches, ford -deep water, cut -thick trees, and climb 40° gradients. Needless to say, it was easy to drive.
Beginning in 1937, there was an effort to equip many tanks with a second machine gun in the rear of the turret and an anti-aircraft machine gun on top of it, as well as the addition of two searchlights above the gun for night gunnery, a new VKU-3 command system, and a TPU-3 intercom. Some tanks had a vertically stabilised TOP-1 gun telescopic sight. Ammunition stowage for the main gun was increased from 122 rounds to 147. In 1938, the cylindrical turret was replaced with a conical turret, with the same 45 mm model 1934 gun. Some T-26s mod. 1938/1939, equipped with radio set, had a PTK commander's panoramic sight.
In 1938, the T-26 was upgraded to the model 1938 version, which had a new conical turret with better anti-bullet resistance but the same welded hull as the T-26 mod. 1933 produced in 1935–1936. This proved insufficient in the Battle of Lake Khasan in 1938, so the tank was upgraded once more in February 1939 to have an underturret box with sloped 20 mm side armoured plates. The turret featured an increase to 20 mm at 18 degrees sloping. This time it was designated T-26-1. There were subsequent attempts to thicken the front plate, but T-26 production soon ended in favour of other designs, such as the T-34.