Douglas F4D Skyray

The Douglas F4D Skyray (later redesignated F-6 Skyray) is an American carrier-based supersonic fighter/interceptor designed and produced by the Douglas Aircraft Company. It was the last fighter produced by the Douglas Aircraft Company before the company merged with McDonnell Aircraft to become McDonnell Douglas.

In the late 1940s, Douglas and the U.S. Navy launched the D-571-1 design study, which called for delta wing interceptor that could climb quickly enough to intercept approaching bombers. Chosen by the Navy to fulfill a formal requirement issued in 1948, the plane was initially designed around the Westinghouse J40 turbojet engine, but required a redesign for the Pratt & Whitney J57 after the J40 was cancelled. Aerodynamic problems prolonged development; considerable design changes were made after the maiden flight of the first production-standard Skyray in June 1954. The Skyray was declared ready for fleet introduction in April 1956 and entered service with both the United States Navy (USN) and United States Marine Corps (USMC) shortly thereafter.

The Skyray had a relatively brief service life and never saw combat. It was the first carrier-launched aircraft to hold the world's absolute speed record: 752.943 mph, (1,211.487 km/h). It is widely reported as the first naval fighter to break the speed of sound in level flight rather than in a dive. The Skyray also set a new time-to-altitude record, flying from a standing start to 49,221 feet (15,003 m) in two minutes and 36 seconds at a 70° pitch angle. The last Skyrays were withdrawn from service in February 1964, although a handful were flown for experimental purposes by National Advisory Committee for Aeronautics (NACA) up to the end of the decade. The F5D Skylancer was an advanced development of the F4D Skyray that did not enter service.