The Wasp Major was Pratt & Whitney Aircraft's last and largest piston engine. Its cylinders were in four rows, arranged in a spiral for better cooling. Initially producing 2,237 kW (3,000 shp), later models developed 3,207 kW (4,300 shp). It was reliable in flight, but required extensive and time consuming checks at startup and shutdown.
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 was used on the Boeing B-50 "Lucky Lady" when it made the first non-stop around the world flight in 1949.
This artifact powered a Boeing Model 377 Stratocruiser, one of the last generation of large propeller-driven commercial airliners. It is a Q.E.C. (Quick Engine Change) unit, complete with engine cowling, designed for rapid engine changes to minimize aircraft out-of-service time.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.