The Northrop XP-79 originated in 1942 as an idea by John K. Northrop for a high-speed flying wing fighter aircraft powered by a rocket engine. Near-sonic speeds were envisaged. The idea was somewhat similar to that which eventually produced the Messerschmitt Me 163 rocket-powered interceptor in Germany.
The Northrop fighter project was to be powered by a 2000 pound thrust Aerojet rocket engine, with takeoff being assisted by a pair of 1000 pound thrust rocket boosters which would be dropped after takeoff. The Aerojet rocket engine was to be powered by hypergolic fuels which combust simply by mixing. Northrop proposed that this airplane be flown by a pilot lying prone in the cockpit, since it was hoped that this would reduce strain on the pilot during violent maneuver and would present a minimum silhouette to enemy gunners.
In January of 1943, the USAAF issued a contract for three prototypes under the designation XP-79. The availability of jet engines led to a decision in March to replace the rocket engine by two Westinghouse 19-B turbojets in the third prototype, which was redesignated XP-79B.
Since the layout of the fighter was so radical, it was thought that test glider prototypes should be built to verify the validity of the concept. One of these was designated MX-324, and was fitted with a fixed tricycle landing gear. The MX-324 was towed into the air by a P-38 on July 5, 1944, and became the first American-built rocket-powered aircraft to fly.
Delays in the development of the Aerojet rocket engine caused the USAAF to cancel the two XP-79s, leaving only the XP-79B. The serial number of the XP-79B was 43-52437. The XP-79B was finally ready for flight testing in the summer of 1945. The pilot lay prone in an unpressurized cockpit situated between the two turbojets. The flying wing was of semimonocoque construction and was built largely of magnesium in order to save weight. Instead of conventional ailerons, the wing had air intakes at the tips for lateral control, in much the same manner as the XP-56. The aircraft was equipped with a pair of vertical tails, presaging the MiG-25 and the F-15. The retractable landing gear consisted of four wheels, two each in tandem.
Supposedly, the XP-79B was to use a rather unusual technique for destroying enemy aircraft. The wing leading edge was reinforced so that it could slice off the wings or tails of enemy aircraft by ramming them! It turns out that this was never true, the ramming claim being a PR gimmick that got out of hand. But it eventually became part of the historical lore, being accepted as truth by numerous aviation historians. Actually, the XP-79B planned to destroy enemy aircraft strictly by conventional means, being equipped with an armament of four 0.50-inch machine guns in the wing leading edge. It was true that there was indeed an armored wing leading edge, but this was intended to protect the aircraft from head-on gunfire.
The XP-79B was transferred to Muroc Dry Lake in June of 1945. Flight testing was delayed by problems with bursting tires during ground taxiing trials. On September 12, 1945, test pilot Harry Crosby finally took the XP-79B up in the air for the first time. It flew all right for about fifteen minutes, but the plane then suddenly went into a spin from which it proved impossible to recover. Crosby attempted to parachute to safety, but his chute failed to open and he was killed. The XP-79B impacted in the desert and was destroyed in the resulting fire. Magnesium burns very nicely. :-).
Although the mishap that cost Harry Crosby his life could have been corrected, the USAAF decided to abandon the project.
Specification of the XP-79B:
Powered by a pair of 1365 lb. st. Westinghouse 19B turbojets. Wingspan was 28 feet, length 14 feet, and height was 7 feet. Wing area was 278 square feet. Gross weight was 8669 pounds. Estimated performance included a maximum speed of 547 mph at 20,000 feet, an initial climb rate of 4000 feet, a service ceiling of 40,000 feet, and a range of 993 miles. The proposed armament of four 0.50-in machine guns was never fitted.
Sources:
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American Combat Planes, Ray Wagner, Third Enlarged Edition, Doubleday,
1982.
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The American Fighter, Enzo Angelucci and Peter Bowers, Orion Books, 1987
- E-mail from Gerald Balzer on myth of the XP-79B being intended to ram enemy aircraft.
