ZSU-37

ZSU-37
Type	Self-propelled anti-aircraft gun
Place of origin	Soviet Union
Specifications
Weight	11.5 tonnes
Length	5.25 m (17 ft 3 in)
Width	2.75 m (9 ft)
Height	2.18 m (7 ft 2 in)
Crew	6 men
Armor	6-35 mm
Main armament	1 x 37 mm automatic air defence gun M1939 (61-K)
Engine	forced GAZ-203 (two tandem 6-cylinder row liquid-cooled gasoline engines GAZ-202) 160 hp (120 kW)
Suspension	torsion bar
Operational range	Road: 360 km (220 mi) Off-road: 230 km (140 mi)
Speed	Road: 45 km/h (28 mph) Off-road: 30 km/h (19 mph)

ZSU-37 was a Soviet-made, light, self-propelled anti-aircraft gun (SPAAG), developed by the end of 1943 and produced at Works No. 40 in Mytishchi. It was the first Soviet series-produced tracked SPAAG. ZSU stands for Zenitnaya Samokhodnaya Ustanovka (Russian: Зенитная Самоходная Установка), meaning "anti-aircraft self-propelled mount".

Soviet engineers carried out some early experiments with tracked SPAAGs before and during World War II, including a modification of the T-70 light tank, resulting in the experimental T-90 SPAAG which was armed with two 12.7 mm DShKT heavy machine guns (the prototype was built in November 1942 by GAZ). The T-70 light tank would eventually be further developed into the SU-76 light self-propelled gun chassis, which in turn was to become the base for the ZSU-37 SPAAG. It was decided to use the chassis of the SU-76M in order to speed up and cheapen the production of the much needed tracked and armoured SPAAGs.

The ZSU-37 was produced from March 1945 to 1948, and 75 vehicles were built in total (only a few vehicles were produced before the war ended, due to temporary manufacturing technology). As a result of its late production and the almost non-appearance of the few remaining Luftwaffe aircraft in the spring of 1945, the ZSU-37 saw no service in World War II. An experimental self-propelled anti-aircraft artillery battalion equipped with 12 ZSU-37 SPAAGs was formed by the end of 1945.

After World War II it became clear that the low rate of fire and firepower of a single 37 mm AA gun was not effective against high-speed low altitude targets. The anti-aircraft artillery crews found it difficult to manually track fast-moving targets. SPAAGs based on a light tank chassis also had quite low manœuvrability in difficult terrain and low off-road speed and range in comparison with medium tanks and self-propelled guns (SPG)s, which the ZSU-37 was meant to protect. The two tandem engines used on the SU-76M chassis required gasoline fuel, which was sometimes a problem in tank units equipped with diesel-engined tanks. The ZSU-37 was retired from service because of the aforementioned reasons soon after series production was stopped.