P-79 to P-81 Air Force Fighters
The end of the Second World War also ended production of propeller-driven single-seaters for the Army Air Force. Development of jet propulsion made most existing fighters obsolescent, and the postwar period saw production of new jet types to re-equip the world fighter units.
Nuclear bombs, and strategic elements of the growing cold war between America and Russia tended to center Air Force attention on bombers rather than fighters, and not until the unexpected appearance of Soviet atomic weapons in 1949 did jet fighter production reach really large numbers. The terrible destructive capability of bombardment now lent a new urgency to development of defensive weapons. Only the ability to clear skies of enemy intruders seemed to offer any shield against annihilation.
Although the United States had no jets ready in time for combat during the big war, wartime development had begun projects from the XP-79 to the XP-86, and had gotten the P-80 Shooting Star into successful production. At the opening of the Korean War in 1950, Air Force fighters in actual service still consisted almost entirely of types begun before the end of World War II.
Even before the first American jet, the Bell XP-59, flew, Jack Northrop proposed on September 15, 1942, a tailless flying wing “jet-driven interceptor”. By December 1942 that design became his NS-14, to be operated by a pilot lying prone in the cockpit. It was hoped that this prone position would reduce strain on the pilot during violent maneuvers and sudden pullouts, and present a minimum target to enemy gunners.
On January 12, 1943, the Air Force authorized purchase of three XP-79 prototypes to be built under Northrop subcontract by Avion, Inc., since Northrop’s factory was too busy to undertake more work. They were designed for 2,000-pound static thrust Aerojet rockets, but in March the more certain availability of the Navy’s Westinghouse l9-B axial-flow jet engines led to a decision to use two jets in the third ship, designated XP-79B.
The radical layout required tryouts in the form of towed gliders with fixed tricycle gear. One, the MX-324, was towed into the air by a P-38 and became the first rocket-powered U.S. aircraft to fly on July 5, 1944. Aerojet was unable, however, to perfect a rocket motor suitable for the XP-79, so both prototypes were canceled in September.
This left only the XP-79B, which was trucked to the Dry Lake near Muroc for testing in June 1945. Sitting low on the ground, it had four retractable wheels and twin vertical fins atop the jet exhaust. The welded magnesium flying wing had air bellows-operated split-flap wingtip rudders outboard of elevons, as on the XP-56, and was armed with four .50 caliber guns.
The wing itself was constructed of a heavy gauge to provide some protection for the fuel tanks and prevent a dangerous mix of the two rocket fuels originally planned. On its first test flight at Muroc Army Airfield, delayed to September 12, 1945, the XP-79B crashed, test pilot Harry Crosby was killed, and the project ended.
Given nearly complete authority and independence from the rest of the Burbank company, that organization became known as the “Skunk Works” and was so successful that this system was used for the most important future Lockheed projects begun in secret, such as the XF-104, U-2, and A-12/YF-12.
In 143 days a neat dark green prototype was finished and the engine installed. But an accident during the run-up damaged that engine, and another had to be imported so that Milo Burcham could make the first XP-80 flight on January 8,1944, from Muroc (Edwards AFB since 1949). Although the engine developed only 2,460-pound static thrust, instead of the 3,000-pounds expected, the Lockheed XP-80 did 502 mph, and became the first American plane that fast.
Propelled by the jet exhaust from the tail, the fighter had the engine behind the pilot fed by twin air intakes ahead of the wing roots. There was a clear plastic canopy, and six .50-caliber guns with 1,200 rounds low in the nose. Like all future jet fighters, the XP-80 sat low on retractable tricycle landing gear.
General Electric had prepared a larger jet engine, the I-40 (became J33 in April 1945), so two more prototypes were ordered on February 16, to be followed by 13 service examples ordered March 10, and the first production letter contract was made on April 2, 1944. First flown June 1, 1944, by Tony LeVier, the GE-powered XP-80A introduced the similar, but heavier, airframe followed on production models. While the first American jets, the Bell P-59s, had been less agile than regular fighters, the Air Force now had a fighter worthy to meet Germany’s Me 262.