Boeing XC-97 Sets a Speed Record

In 1945 the Boeing XC-97, an experimental military transport derived from the B-29 Superfortress, set a notable transcontinental speed record. On one demonstration flight the prototype flew from Seattle, Washington, to the Washington, D.C., area in about six hours, underscoring the performance gains possible by adapting heavy-bomber technology to cargo and passenger carriage.

The XC-97 mated the wings, engines, and tail of the B-29 to a new, capacious double-deck fuselage. Fully pressurized for high-altitude flight, the aircraft was capable of cruising speeds in the neighborhood of 380 miles per hour, exceptional for a large transport of its day.

The design matured into the C-97 Stratofreighter and the KC-97 aerial tanker, which served the U.S. Air Force for years, while its commercial sibling, the Boeing 377 Stratocruiser, carried airline passengers in luxury. The XC-97 thus bridged the wartime bomber and the postwar era of large pressurized transports.