Jacobs (Pratt & Whitney Wasp Jr.) R-985-AN5, Radial 9 Engine
date: label: Date
content: Circa 1940
name: label: Manufacturer
content: Jacobs Aircraft Engine Company (Pottstown, Pennsylvania)
label: Designer
content: Pratt & Whitney
notes: label: Physical Description
content: Type: Reciprocating, 9 cylinders, radial, air cooled
label: Physical Description
content: Power rating: 336 kW (450 hp) at 2,300 rpm
label: Physical Description
content: Displacement: 16.1 L (985 cu in.)
label: Physical Description
content: Bore and Stroke: 132 mm (5.2 in.) x 132 mm (5.2 in.)
label: Physical Description
content: Weight: 310.3 kg (684 lb)
label: Summary
content: 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. Virtually a Wasp of reduced dimensions, the Wasp Jr. followed closely the details of construction throughout. The Wasp Jr., originally rated at 224 kW (300 hp), was first type certificated in January 1930. Designed for light transports, trainers, sport aircraft, and helicopters, number of R-985 models were made, most at 298 kW (400 hp) or more power. The R-985 powered a wide variety and large number of military and commercial aircraft, making it one of the most successful reciprocating engines ever built in its power class.
label: Summary
content: The Jacobs Aircraft Engine Company of Pottstown, Pennsylvania built this Pratt & Whitney-designed R-985-AN5. Jacobs converted it for vertical helicopter installation. It powered the Sikorsky XH-5, YH-5A/D/E, H-5A/D/F/G and Kellett YH-10 helicopters.
place: label: Country of Origin
content: United States of America
setName: label: See more items in
content: National Air and Space Museum Collection
creditLine: label: Credit Line
content: Transferred from the U.S. Air Force Central Museum
dataSource: label: Data Source
content: National Air and Space Museum
identifier: label: Inventory Number
content: A19600112000
objectType: label: Type
content: PROPULSION-Reciprocating & Rotary
objectRights: label: Restrictions & Rights
content: CC0
physicalDescription: label: Materials
content: HAZMAT: Cadmium Plating
label: Materials
content: Steel, Aluminum, Paint, Preservative coating, Leather, Rubber, Copper
label: Dimensions
content: Other: 46 1/4 x 48 x 53 x 54 x 49 3/4in. (117.5 x 121.9 x 134.6 x 137.2 x 126.4cm)
label: Dimensions
content: Approximate (Weight on Stand): 430kg (948lb.)
label: Dimensions
content: Diameter 117.5 cm (46.25 in.), Length 121.9 cm (48 in.)