Northrop N-1M

N-1M
Northrop N-1M on display at the National Air and Space Museum's Steven F. Udvar-Hazy Center. Restored to its final flight configuration.
Role	Flying wing
Manufacturer	Northrop
Designer	Jack Northrop
First flight	3 July 1941
Retired	1945
Status	Experimental
Primary user	Northrop Corp.
Number built	1
Variants	Northrop N-9M

The Northrop N-1M, also known by the nickname "Jeep", was an American experimental aircraft, used in the development of the flying wing concept by Northrop Aircraft during the 1940s.

Design and development

Jack Northrop was involved in innovative all-wing designs in the late-1920s, with his first designs flying in the 1928–1930 period. The first prototype, the 1929 "Flying Wing (X-216H)", evolved from earlier design studies, had twin rudders with a single horizontal stabilizer between them that were connected by twin booms to a thick, all-wing fuselage. The aircraft had an open cockpit in the centre section, with a single, rear-facing, "pusher" type propeller connected to an engine blended into the all-wing shape. The aircraft had adequate performance and was noted for its unique all-metal, stressed skin, multi-cellular construction. First test flown in 1929 with Edward Bellande at the controls, at around the time Northrop became aware of Walter and Reimar Horten's pre-war record-setting "tailless" flying wing glider designs being tested in Germany.

The N-1M was one of a progression of experimental aircraft that further developed Northrop's all-wing concept. It was produced in the United States and was developed during 1939 and 1940 as a flying testbed for the purpose of proving Jack Northrop's vision of a practical Flying Wing. Built mostly of specially laminated layers of glued wood, the wing design allowed easy configuration changes, with a center skeleton made of tubular steel. The diminutive, twin engined test aircraft served its purpose well, first taking to the skies on 3 July 1941 at Baker Dry Lake in California.

Operational history

Northrop's Chief Test Pilot Vance Breese flew the N-1M on its maiden flight, unexpectedly bouncing into the air during a planned high speed taxi run. He reported that the aircraft could fly no higher than five feet off the ground. Flight could only be sustained by maintaining a precise angle of attack, but Theodore von Kármán solved the problem by making adjustments to the trailing edges of the elevons. Control of the aircraft was achieved through the use of a system of elevons and wing tip rudders. The elevons served in tailless type aircraft both as elevators and ailerons, while split flaps on the downward angled wingtips took the place of a conventional rudder; they were later straightened after that angle proved unnecessary during flight testing.

The flight test program continued with Moye W. Stephens, Northrop Test Pilot and Secretary to the Northrop Corporation, serving as a test pilot. Early tests showed the N-1M to be satisfactory in stability and control but overweight and underpowered. The aircraft's two 65 hp Lycoming 0-145 four-cylinder engines (buried in the wing to reduce drag) were replaced by two 120 hp six-cylinder 6AC264F2 air-cooled Franklin engines. By November 1941, after having made some 28 flights, Stephens reported that when attempting to move the N-1M about its vertical axis, the aircraft had a tendency to "Dutch roll." The oscillations proved to be manageable when adjustments were made to the aircraft's wing configuration.

The N-1M proved to be basically sound, paving the way for Northrop's later and much larger Flying Wing aircraft. The pioneering aircraft was then donated to the United States Army Air Forces in 1945 and was placed in the storage collection of the National Air Museum the following year. It sat there for nearly three decades but was finally brought back to static, non-flying status, in its final flight configuration, after several years of painstaking restoration during the 1980s; the N-1M is now on public display at the National Air and Space Museum's Steven F. Udvar-Hazy Center.

Specifications (N-1M)

Data from American X&Y Planes

General characteristics

• Crew: 1
• Length: 17 ft 11 in (5.46 m)
• Wingspan: 38 ft 8 in (11.79 m)
• Height: 4 ft 11 in (1.50 m)
• Wing area: 350 sq ft (33 m²) (approx)
• Gross weight: 3,900 lb (1,769 kg)
• Powerplant: 2 × Lycoming O-145 four-cylinder horizontally opposed air-cooled piston engines, 65 hp (48 kW) each (original engines)
• Powerplant: 2 × Franklin 6AC-264F2 six-cylinder air-cooled horizontally opposed piston engines, 117 hp (87 kW) each (after reengining)

Performance

• Maximum speed: 200 mph (320 km/h; 170 kn)
• Range: 300 mi (261 nmi; 483 km)
• Service ceiling: 4,000 ft (1,219 m)

See also

Related development

• Northrop N-9M
• Northrop YB-35
• Northrop YB-49
  

References

Notes

Citations

Bibliography

• Coleman, Ted. Jack Northrop and the Flying Wing: The Real Story Behind the Stealth Bomber. New York: Paragon House, 1988. ISBN 1-55778-079-X.
• Darling, Kev. American X&Y Planes: Volume 1: Experimental Aircraft to 1945. Marlborough, UK: The Crowood Press, 2010, First edition 2009. ISBN 978-1847971418.
• Donald, David, ed. "Northrop Flying Wings". Encyclopedia of World Aircraft. Etobicoke, Ontario: Prospero Books, 1997. ISBN 1-85605-375-X.
• Maloney, Edward T. Northrop Flying Wings. Corona del Mar, California: World War II Publications, 1988. ISBN 0-915464-00-4.
• O'Leary, Michael. "Wings of Northrop, Part One". Air Classics, Volume 43, Number 12, December 2007, Challenge Publications, Inc. ISSN 0002-2241.
• Pape, Garry and John Campbell. Northrop Flying Wings: A History of Jack Northrop's Visionary Aircraft. Atglen, PA: Schiffer Publishing, Ltd., 1995. ISBN 0-88740-689-0.

External links

• Northrop N-1M at the Smithsonian National Air and Space Museum
• Flying Wings Are Coming, March 1942