The Douglas X-3 Stiletto was the sleekest of the early experimental aircraft, but its research accomplishments were not those originally planned. It was originally intended for advanced Mach 2 turbojet propulsion testing, but it fell largely into the category of configuration explorers, as it never met its original performance goals due to inadequate engines. The goal of the aircraft was ambitious—it was to take off from the ground under its own power, climb to high altitude, maintain a sustained cruise speed of Mach 2, then land under its own power. The aircraft was also to test the feasibility of
low-aspect-ratio wings, and the large-scale use of titanium in aircraft structures. The design of the Douglas X-3 Stiletto is the subject of U.S. Design Patent #172,588 granted on July 13, 1954, to Frank N. Fleming and
Harold T. Luskin and assigned to the Douglas Aircraft Company, Inc. Construction of a pair of X-3s was approved on 30 June 1949. During development, the X-3's planned
Westinghouse J46 engines turned out to be too large to fit inside the fuselage, so lower-thrust
Westinghouse J34 turbojets were substituted, producing only of thrust with afterburner rather than the planned . The first aircraft was built and delivered to
Edwards Air Force Base,
California, on 11 September 1952. The X-3 had a slender streamlined fuselage with a very long, gently tapered nose and small
trapezoidal wings. The aim was to achieve the lowest possible drag at supersonic speeds. The extended nose was to accommodate test equipment, while the semi-buried cockpit and windscreen were designed to alleviate the effects of
Aerodynamic heating. The low aspect ratio unswept wings were designed for high speed, and later the
Lockheed design team used data from the X-3 tests for the similar
F-104 Starfighter wing. Due to both engine and airframe problems, the partially completed second aircraft was cancelled, and its components were used for spare parts. ==Operational history==