Staff Writer (Updated: 10/2/2015):
With this in mind, the United States Navy (USN) looked to grow its stable of fighters beyond its conventionally-arranged, piston-powered types. As many of the major defense industry players were tied to the production of much-needed aircraft for immediate service, the U.S. Navy Bureau of Aeronautics approached McDonnell in January of 1943 to partner on a new single-seat, jet-powered monoplane fighter project. The engine of choice was an equally-new turbojet development offered from Westinghouse. The aircraft was given the designation of "FD-1".
McDonnell had revealed itself to be a rather forward-thinking company with its previous XP-67 "Moonbat" heavy fighter / interceptor development. While not adopted into service form - and only one flyable prototype completed - the Moonbat made McDonnell stand out as an aircraft builder. Additionally it did not hold the production commitment to the ongoing war as its competitors did.
In the short span of two years, McDonnell engineers had readied the "XFD-1" prototype which first took to the air on January 26th, 1945. The aircraft proved a sleek design featuring a well-streamlined fuselage, straight wing appendages (with clipped tips) and a single-finned tail unit. A wholly-retractable tricycle undercarriage was fitted and the airframe was powered by two of the aforementioned jets buried in the wingroots, exhausting through rounded ports at the wingroot aft. Because the engines could be mounted at any point behind the pilot, vision out-of-the-cockpit was vastly improved for navy aviators (no forward-mounted engine or spinning propellers to contend with and therefore a shorter distance between the cockpit and nose of the aircraft). Standard, fixed armament centered on 4 x 0.50 caliber heavy machine guns, all fitted to the nose. There was also support for 8 x 5" (127mm) High Velocity Aircraft Rockets (HVARs) underwing intended to help bring down large, slow-moving targets like bombers.