Pratt & Whitney R-985 Wasp Junior

The Pratt & Whitney R-985 Wasp Junior is a nine-cylinder supercharged air-cooled radial engine.   Over 39,000 of these engines were built from the 1930s to the 1950s.  They powered numerous civil and military aircraft, small transports, utility aircraft, trainers, crop dusters and helicopters.  It is one of the most reliable engines ever built.  Major Applications: Beechcraft M17 and M18, de Havilland DHC-2 Beaver, Grunman G-21 Goose, Sikorsky H-5, Vought OS2U Kingfisher, Vultee BT-13 Valiant, Boeing Stearman M75.

Engine NamePratt & Whitney R-985
Manufactured byPratt & Whitney
Cylinder ConfigurationRadial
Number of Cylinders9
Displacement (cubic inches)985
Bore (inches)5.187
Stroke (inches)5.187
Horsepower300-450
Dry Weight (lb)640