The Wasp Major was Pratt & Whitney’s last big piston engine. Reliable in flight, it required extensive and time consuming checks at startup and shutdown. But even though four rows in the radial configuration seems a cooling problem, staggering each of its rows of seven cylinders effectively cooled the Wasp Major.

Beginning in 1941, the gigantic Convair B-36 strategic bomber was likely planned around this engine, which used six R-4360s along with four turbojets. The Wasp Major saw service at the end of World War II in late Boeing B-29s that were actually early B-50s, and powered the Boeing B-50 "Lucky Lady" when it made the first non-stop around the world flight from Fort Worth, Texas, in 1949.

Other principal applications were in the Douglas C-124 Globemaster and the civilian Boeing Stratocruiser, a derivation of the B-50.

 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 1946 Country of Origin United States of America Type PROPULSION-Reciprocating & Rotary Manufacturer Pratt & Whitney
 Physical Description Type: Reciprocating, 28 cylinders, 4-rows, radial, air cooled Power rating: 3,207 kW (4,300 hp) at 2,800 rpm Displacement: 71.5 L (4,360 cu in.) Bore and Stroke: 146 mm (5.8 in.) x 152 mm (6.0 in.) Weight: 1,687.4 kg (3,720 lb) Dimensions Diameter 137.2 cm (54 in.), Length 259.1 cm (102.0 in.)
 Inventory Number A19600123000 Credit Line Transferred from the U.S. Air Force Central Museum Data Source National Air and Space Museum Restrictions & Rights Usage conditions apply
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