Pratt & Whitney R-4360 Wasp Major

The Pratt & Whitney R-4360 Wasp Major is an American 28-cylinder four-row radial piston aircraft engine designed and built during World War II. At 4,362.5 cu in (71.5 L), it is the largest-displacement aviation piston engine to be mass-produced in the United States, and at 4,300 hp (3,200 kW) the most powerful. The prototype first ran on 28 April 1941, with production-standard engines running in 1944.

Source: Wikipedia — Pratt & Whitney R-4360 Wasp Major (CC BY-SA 4.0)