One of two prototype Douglas XSB2D-1 Destroyer torpedo/dive bombers prepares to land during flight tests in 1943. (U.S. Navy Photograph.)
Tag - prototype
The sole prototype of the Grumman XF5F Skyrocket fighter/interceptor flies past the cameraman to show its unique design. (U.S. National Archives and Records Administration Photograph.)
Prototype Curtiss XF15C-1 photographed in flight in 1945. (U.S. Air Force Photograph.)
The Curtiss XP-40 Warhawk fighter undergoes drag-reduction testing in the full-scale wind tunnel at Langley Research Center in 1939. (NASA Photograph.)
The Chance Vought XF4U-1 Corsair prototype photographed during testing at the National Advisory Committee for Aeronautics (NACA) Langley Research Center in Hampton, Virginia in 1941. (NASA Photograph.)
The Northrop XBT-2 prototype which would be the basis of the later Douglas SBD Dauntless, July 1938. (U.S. Navy Photograph.)
Prototype of the North American XB-28 (NA-63) Dragon developed as a high-altitude medium bomber. (U.S. Air Force Photograph.)
A U.S. Navy Grumman XF4F-3 Wildcat prototype photographed during flight testing in 1939. (U.S. Navy Photograph.)
Experimental North American P-51D Mustang with pulsejets mounted under the wings. (U.S. Air Force Photograph.)
Convair XA-41 (also known as the Vultee XA-41) during an engine run. One prototype was completed primarily as an engine testbed for the Pratt & Whitney R-4360. (U.S. Air Force Photograph.)