T-26

T-26 was one of the most numerous tanks in Soviet Union service in World War II.

Background
One of the most numerous tanks in Soviet service, the T-26 was an evolution of the British Vickers-Armstrong 6-Ton tank. While unsuccessful with the British Army, the design was purchased by numerous foreign countries, including the Soviet Union. Arriving in the USSR between 1930 and 1932, along with full technical documentation for manufacturing, the tanks was put in service as the T-26.

It was not a simple copy of the Vickers 6-Ton, as it received numerous modifications over the course of its service, including new turrets, armor increases, better armament, radio sets, better engines, and eventually a fully welded, rather than riveted hull. It remained as the primary tank of the Red Army's tank units and hundreds were provided to Spain, China, and Turkey before the outbreak of the war, although by the early forties its deficiencies became clear, especially its limited armor thickness and mobility.

Although its flaws were evident, the T-26 remained in service into 1941, with over ten thousand available on the eve of Fall Barbarossa. Most were lost in the first months of the campaign, and was gradually replaced in service by the much more capable T-34. However, captured units remained in service with Axis forces and their allies, while the last Soviet units to use the T-26 seized Manchuria in late 1945.

Model 1933 (T-26B)
The 1933 model of of the T-26, referred to as a T-26B, was fitted with a cylindrical turret and a large rear niche. By 1935, all models of this type were manufactured with welding, rather than riveting, and were mass produced to eventually become the most commong version of the T-26 encountered by the Union's foes.
 * T-26B (Fin): Finland designated captured Model 1933 T-26 as T-26B. These tanks were the most common variant of the T-26 used the the Panssariprikaati (Tank Brigade). 20 were captured during the Winter War while 65 T-26B were captured during the  Continuation War.
 * T-26 Komroti: A 1933 model used as a command vehicle.

Model 1938 (T-26C)
The 1938 model received a new, conical turret with a smaller cross-section, a slew of minor modifications to the hull design, and additional upgrades for the main gun and its optics.
 * Panzer T-26C(r): Captured T-26 tanks were pressed into service by the Nazis as Panzerkampfwagen 740(r).
 * T-26C (Kpääl): Finland designated captured Model 1938 T-26 as T-26C. These tanks used the the Panssariprikaati (Tank Brigade). 32 to 36 T-26C were used in Finnish service. These tanks were commonly issued to platoon and company leaders since the tanks were usually equipped with radios.

Screened
The Ekranirovanny (screened) version of the T-26 was developed specifically for the Winter War. By using additional plates mounted with bolts and welding, the tank was provided with up to 40mm of additional armor, giving it greatly increased protection against Finnish light anti-tank guns.
 * T-26E: The basic Soviet variant.
 * T-26E (Fin): After the Winter War, Finland replaced the Armaments and turret of their remaining 26 Vickers 6-ton tanks with captured soviet equipment. The 37 mm tank gun M/36 Bofors was replaced by Soviet 45-mm tank guns to simplify supply lines of the Panssaridivisioona. The more reliable DT replaced the original M/09-31 (tank) machinegun. Soviet optics replaced the original optics even thought the Soviet optics has poorer visibility, they were better for estimating range.

Chemical (flame) tank
T-26 based chemical tanks (Химический Танк, Khimicheskiy Tank) carried a powerful flamethrower instead of the 20-K 45mm gun in the turret and were used for urban warfare and clearing out fortified positions, as well as smoke screening and other duties. The name was a common term for these types of tanks, with the OT designation used post war.
 * KhT-130: The Soviet unit.

Artillery tank
The SU-76 was a T-26 with the turret removed and a modified superstructure designed to accommodate a rear-mounted 76.2mm regimental gun.
 * SU-76P