The Northrop XP-79, USAAF project number MX-365, was an ambitious design for a

flying wing A flying wing is a tailless fixed-wing aircraft that has no definite fuselage, with its crew, payload, fuel, and equipment housed inside the main wing structure. A flying wing may have various small protuberances such as pods, nacelles, blis ...

fighter aircraft Fighter aircraft are fixed-wing military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air superiority of the battlespace. Domination of the airspace above a battlefield ...

, designed by Northrop. It had several notable design features; among these, the pilot would operate the

aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...

from a lying position, permitting the pilot to withstand much greater ''g''-forces in the upward and downward direction with respect to the plane – and welded magnesium monocoque structure instead of riveted aluminum.

Design and development

In 1942, John K. (Jack) Northrop conceived the XP-79 as a high-speed rocket-powered flying-wing fighter aircraft. In January 1943, a contract for two prototypes (s/n 43-52437 & 43-52438) with designation XP-79 was issued by the

United States Army Air Forces The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...

(USAAF). Originally, it was planned to use a thrust XCALR-2000A-1 "rotojet" rocket motor from

Aerojet Aerojet was an American rocket and missile propulsion manufacturer based primarily in Rancho Cordova, California, with divisions in Redmond, Washington, Orange and Gainesville in Virginia, and Camden, Arkansas. Aerojet was owned by GenCorp. ...

that used mono-ethylaniline fuel and

red fuming nitric acid Red fuming nitric acid (RFNA) is a storable oxidizer used as a rocket propellant. It consists of 84% nitric acid (), 13% dinitrogen tetroxide and 1–2% water. The color of red fuming nitric acid is due to the dinitrogen tetroxide, which breaks ...

(RFNA) oxidiser. However, the rocket motor configuration using canted rockets to drive the turbo-pumps was unsatisfactory and the aircraft was subsequently fitted with two

Westinghouse 19B The Westinghouse J30, initially known as the Westinghouse 19XB, was a turbojet engine developed by Westinghouse Aviation Gas Turbine Division, Westinghouse Electric Corporation. It was the first American-designed turbojet to run, and only the seco ...

turbojets and re-designated XP-79B. After the failure of the rocket motor, further development of the first two prototypes ended. To protect the pilot if the aircraft was damaged in combat the XP-79 was built using a welded magnesium alloy monocoque structure with a skin thickness at the trailing edge and a thickness at the leading edge. The pilot controlled the XP-79 through a tiller bar and rudders mounted below; intakes mounted at the wingtips supplied air for the unusual bellows-boosted split ailerons.

MX-324 and MX-334

To test the radical design, Northrop was given a contract to build three glider demonstrators, to designs from the Engineering Division of the USAAF Materiel Division. Given the Northrop designation NS-12, the three gliders were also given project numbers from the USAAF. Confusingly, two project numbers were used, one MX-324 when discussing secret aspects of the powered gliders, and another, MX-334, relating to the aircraft when being built and flown as pure gliders. The MX-334 emerged as a flying wing glider with no tail surfaces, similar in layout and construction to the Northrop N-9M. Completed in late Spring 1943 the no.1 MX-334 was tested in NACA Langley's wind tunnel, after which a large wire-braced fin was added to ensure directional stability at high speeds. The first flight attempts was carried out by the no.2 aircraft towed behind a Cadillac car for low level take-off and landing tests, with no success. After modifications the first launch was carried out on 4 September 1943, towed behind a large truck. For more comprehensive testing, a

Lockheed P-38 Lightning The Lockheed P-38 Lightning is an American single-seat, twin piston-engined fighter aircraft that was used during World War II. Developed for the United States Army Air Corps by the Lockheed Corporation, the P-38 incorporated a distinctive twi ...

was used to tow the aircraft on its first proper flight on 2 October 1943. In early 1944 the no.2 aircraft was modified to take the Aerojet XCAL-200 rocket motor, reverting to the "secret" MX-324 designation. The aircraft was also fitted with combined rudder and airbrakes outboard of the elevons. Testing with the rocket motor commenced on 22 June 1944, with the first aerotow launch for a powered flight on 5 July 1944, making it the first US-built rocket-powered aircraft to fly. Flight testing was concluded by 1 August 1944 and the two remaining aircraft were disposed of. The no.3 MX-334 was written off on its second flight, on 10 November 1943, after Harry Crosby lost control in the prop-wash of the P-38 tug.

Testing

The XP-79B was lost during its first flight on 12 September 1945, following delays due to bursting tires and brake problems on taxiing trials on the

Muroc dry lake Rogers Dry Lake is an endorheic desert salt pan in the Mojave Desert of Kern County, California. The lake derives its name from the Anglicization from the Spanish name, Rodriguez Dry Lake. It is the central part of Edwards Air Force Base as its ...

. While performing a slow roll 15 minutes into the flight, control was lost for unknown reasons. The nose dropped and the roll continued with the aircraft impacting in a vertical spin. Test pilot Harry Crosby attempted to bail out but was struck by the aircraft and fell to his death. Shortly thereafter, the second prototype (43-52438) and the overall project was canceled.

Variants

''Data from:'' Northrop Flying Wings : a history of Jack Northrop's visionary aircraft ;NS-12: Northrop company designation for the MX-324 programme. ;NS-14: Northrop designation for the XP-79 programme. ;MX-324: The "secret" designation for the powered version of the MX-334 glider. Only used for the no.2 glider, when powered by a single Aerojet XCAL-200 liquid-fuelled rocket engine. ;MX-334: The designation used to describe the pure glider version ( including the no.2 aircraft before it was fitted with the rocket engine). ;MX-365: The USAAC project number for the XP-79 programme ;XP-79: The initial design for a rocket powered fighter, to have been powered by 2 x Aerojet XCAL-2000 liquid-fuelled rocket engine. ;XP-79B: Three aircraft were ordered but only one was completed, crashing on its first flight on 12 September 1945.

Specifications (XP-79B)

References

Bibliography

* * Pelletier, Alain J. "Towards the Ideal Aircraft: The Life and Times of the Flying Wing, Part Two". '' Air Enthusiast'', No. 65, September–October 1996, pp. 8–19. .

External links

National Museum of the USAF Fact Sheet: Northrop XP-79B

{{USAF fighters P-79 Northrop P-79 Flying wings Twinjets Prone pilot aircraft Cancelled military aircraft projects of the United States Aircraft first flown in 1945