Northrop XP-56 Black Bullet

The XP-56 Black Bullet was a unique prototype fighter interceptor built by Northrop. It was one of the most radical of the experimental aircraft built during World War II. The idea for this single-seat, initially tail-less, airplane originated in 1939 as the Northrop N2B model. It was designed around the Pratt & Whitney liquid-cooled X-1800 engine in a pusher configuration driving contra-rotating propellers. Design was ordered on June 22, 1940, and a prototype aircraft was ordered on September 26, 1940. Shortly after work had begun, Pratt & Whitney, however, stopped development of the X-1800. The Pratt & Whitney R-2800 engine was substituted, although it was considered not entirely suitable. In parallel, flight trials of the configuration were conducted on the Model N1M airframe with a wing similar to that planned for the XP-56. Two small Lycoming engines powered this aircraft. These trials confirmed the stability of the radical design and the need for a second prototype, which was ordered on February 13, 1942. Taxi tests of the XP-56 began in April 1943 during which a serious yaw problem was discovered that was thought to be caused by the wheel brakes. Manual hydraulic brakes were installed and the aircraft flew on September 30, 1943 at Muroc Air Base in southern California. After a number of flights, the first XP-56 was destroyed when the tire on the left gear blew out. A number of changes were made to the second prototype, including re-ballasting to move the center-of-gravity forward and increasing the size of the upper vertical tail, and the plane flew on March 23, 1944. The pilot had difficulty lifting the nose wheel below 160 mph. This flight lasted less than eight minutes but subsequent flights were longer, and the nose heaviness disappeared when the landing gear was retracted. Only relatively low speeds were attained, however. While urging NACA to investigate the inability to attain designed speeds, further flight tests were made. On the tenth flight the pilot noted extreme tail heaviness, lack of power, and excessive fuel consumption. Flight testing, then, was ceased as too hazardous, and the project was abandoned after a year of inactivity.