The Wasp Jr. R-985 was the third engine type designed by Pratt & Whitney Aircraft, following the Wasp R-1340 and Hornet R-1690, all of which were nine-cylinder engines. The Wasp Jr. was designed to compete at lower power and was virtually a Wasp of reduced dimensions, as the details of construction were followed closely throughout. First certificated in January 1930 at 224 kW (300 hp), the R-985 was designed for light transports, trainers, sport aircraft, and helicopters. A number of models were made, most at 298 kW (400 hp) or higher power.

Powering a wide variety and large number of well known military and commercial aircraft such as the de Havilland Beaver and Lockheed Electra, the Wasp Jr. was one of the most successful reciprocating engines ever built in its power class. The R-985-39A powered the Beech C-45G and C-45H aircraft.

 Display Status

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Object Details
Date Circa World War II Country of Origin United States of America Type PROPULSION-Reciprocating & Rotary Manufacturer Pratt & Whitney
 Physical Description Type: Radial, 9 cylinders, supercharged, air-cooled Power rating: 336 kW (450 hp) at 2,300 rpm Displacement: 16.1 L (985 cu in) Bore and Stroke: 132 mm (5.2 in.) x 132 mm (5.2 in.) Weight: 292.8 kg (645 lb) Dimensions Overall: 645lb. (292.6kg)
Other (R-985-29): 3 ft. 9 3/4 in. × 3 ft. 5 9/16 in. (116.2 × 105.6cm)
Storage: 147.3 × 147.3 × 135.9cm (4 ft. 10 in. × 4 ft. 10 in. × 4 ft. 5 1/2 in.)
 Inventory Number A19840864000 Credit Line Transferred from the U.S. Army, Defense Property Disposal Office, Fort Campbell, Kentucky Data Source National Air and Space Museum Restrictions & Rights Usage conditions apply
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