Pratt & Whitney R-985 Wasp Junior
The Pratt & Whitney R-985 Wasp Junior is a series of nine-cylinder, air-cooled, radial aircraft engines built by the Pratt & Whitney Aircraft Company from the 1930s to the 1950s. These engines have a displacement of 985 in3 (16 L); initial versions produced 300 hp (220 kW), while the most widely used versions produce 450 hp (340 kW).
Source: Wikipedia — Pratt & Whitney R-985 Wasp Junior (CC BY-SA 4.0)