T-34 - Development

Development

In 1939 the most numerous Soviet tank models were the T-26 light tank, and the BT series of fast tanks. The T-26 was a slow-moving infantry tank, designed to keep pace with soldiers on the ground. The BT tanks were cavalry tanks, very fast-moving light tanks, designed for manoeuvre warfare. Both were lightly armoured, proof against small arms but not anti-tank rifles and 37 mm anti-tank guns. During the Battles of Khalkhin Gol, a border war against Japan in 1939, General Zhukov deployed nearly 500 BT-5 and BT-7 tanks against the Imperial Japanese Army (IJA). Although the IJA Type 95 light tanks had diesel engines, the BT tanks did not. Their gasoline engines, commonly used in tank designs by most nations at the time, often burst into flames when hit by IJA tank-killer teams using Molotov cocktails, tank gunfire or "at any other slightest provocation." Both were Soviet developments of foreign designs from the early 1930s; the T-26 was based on the British Vickers 6-Ton, and the BT tanks were based on a design from American engineer Walter Christie.

In 1937, the Red Army assigned engineer Mikhail Koshkin to lead a new team to design a replacement for the BT tanks at the Kharkiv Komintern Locomotive Plant (KhPZ). The prototype tank, designated A-20, was specified with 20 mm (0.8 in) of armour, a 45 mm (1.8 in) gun, and the new Model V-2 engine, using less-flammable diesel fuel in a V12 configuration designed by Konstantin Chelpan. It also had an 8×6-wheel convertible drive similar to the BT tank's 8×2, which allowed it to run on wheels without caterpillar tracks. This feature had greatly saved on maintenance and repair of the unreliable tank track of the early 1930s, and allowed tanks to exceed 85 kilometres per hour (53 mph) on roads, but gave no advantage in combat. By then, the designers considered it a waste of space and weight. The A-20 also incorporated previous research (BT-IS and BT-SW-2 projects) into sloped armour: its all-round sloped armour plates were more likely to deflect anti-armour rounds than perpendicular armour.

Koshkin convinced Soviet leader Joseph Stalin to let him develop a second prototype, a more heavily armed and armoured "universal tank" which could replace both the T-26 and the BT tanks. The second prototype Koshkin named A-32, after its 32 mm (1.3 in) of frontal armour. It also had a 76.2 mm (3 in) gun, and the same V-2 diesel. Both were tested in field trials at Kubinka in 1939, with the heavier A-32 proving to be as mobile as the A-20. A still heavier version of the A-32 with 45 mm (1.8 in) of front armour and wider tracks was approved for production as the T-34. Koshkin chose the name after the year 1934 when he began to formulate his ideas about the new tank, and to commemorate the decree expanding the armoured force and the appointment of Sergo Ordzhonikidze to head tank production.

Lessons from Khalkhin Gol regarding armour protection, mobility, welding and main guns were incorporated into the new T-34 tank, and Koshkin's team completed two prototype T-34s in January 1940. In April and May, they underwent a grueling 2,000-kilometre (1,200 mi) drive from Kharkiv to Moscow for a demonstration for the Kremlin leaders, to the Mannerheim Line in Finland, and back to Kharkiv via Minsk and Kiev. Some drivetrain shortcomings were identified and corrected.