Boeing B-29D/XB-44 Superfortress

Last revised April 17, 2000

The Wright-powered B-29 had always been somewhat underpowered for its weight, and it became clear that the aircraft could take substantially more engine power if it were available. In pursuit of this objective, one B-29A (42-93845) was handed over to Pratt & Whitney for conversion as a testbed for the new four-row 28-cylinder Pratt & Whitney R-4360 Wasp Major air-cooled radial engine, which was rated at 3500 hp. The aircraft was later redesignated XB-44, and was readily recognizable by the new engine installation, with the oil cooler intake pulled further back on the lower part of the nacelle.

An order for 200 production examples under the designation B-29D was placed in July of 1945, but was reduced to only 50 after V-J Day. In December of 1945, the designation of the B-29D was changed to B-50A. This was a ruse to win appropriations for the procurement of an airplane that appeared by its designation to be merely a later version of an existing model that was already being cancelled wholesale, with many existing models being put into storage. Officially, the justification for the new B-50 designation was made on the basis that the changes introduced by the B-29D were so major that it was essentially a completely new aircraft. The ruse worked, and the B-50 survived to become an important component of the postwar Air Force.

Sources:


  1. Warbird History--B-29 Superfortress, Chester Marshall, Motorbooks International, 1993.

  2. The Boeing B-29 Superfortress, Mich Mayborn, Aircraft in Profile, Doubleday, 1969.

  3. B-29 Superfortress, John Pimlott, Gallery Books, 1980.

  4. Famous Bombers of the Second World War, William Green, Doubleday, 1960.

  5. Jane's Fighting Aircraft of World War II, Bill Gunston, Military Press, 1989.

  6. Boeing Aircraft Since 1916, Peter M. Bowers, Naval Institute Press, 1989.

  7. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian Institution Press, 1989.

  8. Jane's Fighting Aircraft of World War II, Bill Gunston, Military Press, 1989.

  9. American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday, 1982.