Douglas X-3 Stiletto High-Speed Research Aircraft Family

The Douglas X-3 Stiletto was a single-seat research aircraft intended to take off under its own power and sustain Mach 2 flight while testing low-aspect-ratio wings and extensive titanium construction. Its substitute Westinghouse J34 engines left it severely underpowered: it exceeded Mach 1 only in a dive. An initial hop on October 15, 1952 preceded the official first flight on October 20. During abrupt-roll tests on October 27, 1954, Joseph Walker encountered severe coupled pitch and yaw motions and recovered the aircraft. Those flights became important evidence for understanding inertial roll coupling in slender, high-speed aircraft. The X-3’s final flight was May 23, 1956; its research value lay in stability, structural loads, materials, and tire technology despite the unrealized Mach 2 objective.