This twin-turbojet X-3 is the only one built. It was designed to test features of an aircraft suitable for sustained flights at supersonic speeds and high altitudes. A secondary mission was to investigate the use of new materials such as titanium and to explore new construction techniques. The X-3 was transferred to the National Museum of the United States Air Force in 1956.
Douglas
X-3 Stiletto
The Stiletto had the most highly refined supersonic
airframe of its day. It made contributions to titanium technology,
and features of its design were used later in Lockheed's
F-104 Starfighter and the
SR-71 Blackbird.