Cross section of a Shvetsov AS-21 radial engine

Number of cylinders:7
Engine capacity:20.605 l
Bore:155.5 mm
Maximum power output:570 HP
Dry weight:486 kg
The development of the single-row, 7-cylinder air-cooled radial engine began in 1945 and was led by Arkadiy Shvetsov. The prototype was completed by 1946. It was produced between 1947 and 1955: during this period 7,636 engines were manufactured. It was mainly installed in the Yakovlev Yak-11 trainer aircraft. It was introduced to Hungary as part of that model. The Hungarian Air Force started using it in 1949 and retired the model in 1960.