Pratt & Whitney R-985 Wasp Junior
Here seen on a Twin Beech. 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 cu in (16.14 L); initial versions produced 300 hp (224 kW), while the most widely used versions produce 450 hp (336 kW). Wasp Juniors have powered numerous smaller civil and military aircraft, including small transports, utility aircraft, trainers, agricultural aircraft, and helicopters. Over 39,000 of these engines were built, and many are still in service today.