World Library  
Flag as Inappropriate
Email this Article

Northrop Gamma

Article Id: WHEBN0003564180
Reproduction Date:

Title: Northrop Gamma  
Author: World Heritage Encyclopedia
Language: English
Subject: Northrop Delta, Northrop Alpha, Northrop Corporation, Northrop aircraft, Northrop XFT
Collection: Northrop Aircraft, United States Civil Utility Aircraft 1930–1939
Publisher: World Heritage Encyclopedia

Northrop Gamma

Northrop Gamma
Northrop 2B Gamma "Polar Star"
Role Civil/Attack
Manufacturer Northrop Corporation
Designer Jack Northrop
Introduction 1932
Number built 60
Developed from Northrop Alpha
Variants Northrop YA-13

The Northrop Gamma was a single-engine all-metal monoplane cargo aircraft used in the 1930s. Towards the end of its service life, it was developed into the A-17 light bomber.


  • Design and development 1
  • Operational history 2
  • Variants 3
  • Operators 4
    • Military Operators 4.1
    • Civil Operators 4.2
  • Specifications (Gamma 2D) 5
  • Gallery 6
  • See also 7
  • References 8
  • External links 9

Design and development

The Gamma was a further development of the successful Northrop Alpha and shared its predecessor's aerodynamic innovations with wing fillets and multicellular stressed-skin wing construction. Like late Alphas, the fixed landing gear was covered in distinctive aerodynamic spats, and the aircraft introduced a fully enclosed cockpit.

Operational history

The Polar Star on display at the National Air and Space Museum

The Gamma saw fairly limited civilian service as mail planes with Trans World Airlines but had an illustrious career as a flying laboratory and record-breaking aircraft. The US military found the design sufficiently interesting to encourage Northrop to develop it into what eventually became the Northrop A-17 light attack aircraft. Military versions of the Gamma saw combat with Chinese and Spanish Republican air forces.[1] Twenty Five Gamma 2Es were assembled in China from components provided by Northrop.[2]

On June 2, 1933 Frank Hawks flew his Gamma 2A "Sky Chief" from Los Angeles to New York in a record 13 hours, 26 minutes, and 15 seconds. In 1935, Howard Hughes improved on this time in his modified Gamma 2G making the west-east transcontinental run in 9 hours, 26 minutes, and 10 seconds.[1]

The most famous Gamma was the "Polar Star." The aircraft was carried via ship and offloaded onto the pack ice in the Ross Sea during Lincoln Ellsworth's 1934 expedition to Antarctica. The Gamma was almost lost when the ice underneath it broke, and had to be returned to the United States for repairs. Polar Star's second assignment to Antarctica in September 1934 was also futile — a connecting rod broke and the aircraft had to be returned yet again for repairs. On January 3, 1935, Ellsworth and pilot Bernt Balchen finally flew over Antarctica.

On November 23, 1935, Ellsworth and Canadian pilot Herbert Hollick-Kenyon attempted the world's first trans-Antarctic flight from Dundee Island in the Weddell Sea to Little America. The crew made four stops during their journey, in the process becoming the first people ever to visit Western Antarctica. During one stop, a blizzard completely packed the fuselage with snow which took a day to clear out. On December 5, after traveling over 2,400 miles (3,865 km) the aircraft ran out of fuel just 25 miles (40 km) short of the goal. The intrepid crew took six days to travel the remainder of the journey and stayed in the abandoned Richard E. Byrd camp until being found by the Discovery II research vessel on January 15, 1936. "Polar Star" was later recovered and donated to the Smithsonian National Air and Space Museum where it resides to this day.[3]


Gamma 2A
First production aircraft, sold to Texaco and flown by Frank Hawks as "Sky Chief", 785 hp (585 kW) Wright radial engine.[2][4]
Gamma 2B
Two-seat version with tandem controls, flown across Antarctica as the "Polar Star", 500 hp (373 kW) Pratt & Whitney Wasp radial engine.[2]
Gamma 2C (YA-13)
Northrop-proposed attack version to compete with Curtiss A-12 Shrike armed with 4x 0.30 cal machine guns in the wings, 1x 0.30 cal machine gun on a flexible mount for rear defence, and up to 1,100 lb (500 kg) of bombs under the wings, evaluated by USAAC in 1933
YA-13 prototype redesignated after being fitted with a Pratt & Whitney R-1830-9 engine
Gamma 2D
Cargo version used by TWA, three built, 710 hp (529 kW) Wright Cyclone engine.[2] One aircraft was converted into an "Experimental Overweather Laboratory" studying icing, superchargers, radios, and turbulence at 20,000-35,000 ft (6,100–10,670 m), then used by USAAC under the designation UC-100. Another retired TWA aircraft was used by Spanish Republican air force for coastal patrol.
Gamma 2E
Similar to Gamma 2C in armament except for a 1,600 lb (727 kg) bomb load, used by the Republic of China Air Force as a light bomber until 1938 with a number of aircraft built in China, one, as K5053, used by the British Aeroplane & Armament Experimental Establishment, and two supplied to the Imperial Japanese Navy Air Service, as the Northrop BXN, for evaluation in 1933.
Gamma 2F
Another attack version developed in parallel with Gamma 2C, entered service as Northrop A-17 .
Gamma 2G
Two-seat race version, originally with a Curtiss Conqueror engine, later changed to Pratt & Whitney Twin Wasp Jr., then to Wright Cyclone SGR-1820-G-5. Flown by Jacqueline Cochran and Howard Hughes.
Gamma 2H
Testbed for Sperry automatic pilot, also flown by Russell Thaw to a third-place finish in the 1935 Bendix Trophy race.
Gamma 2J
Two-seat trainer powered by 600 hp (448 kW) Pratt & Whitney Wasp with retractable undercarriage intended for USAAC. North American BC-1 preferred. Only one built.[5]
Gamma 2L
Used by Bristol for Bristol Hercules engine testing.
Gamma 5A
One aircraft exported to Imperial Japanese Navy (designation BXN1) as a study in modern engineering.
Gamma 5B
Two-seat version with the cockpits moved forward, used by the Spanish Republican air force for coastal patrol.
Gamma 5D
One aircraft exported to Japan with "Army-type" equipment (designation BXN2), studied by Nakajima, then passed to Manchukuo National Airways which used it for aerial reconnaissance over China and USSR.


Military Operators

 Japan as BXN
 United States

Civil Operators

 United States

Specifications (Gamma 2D)

Data from McDonnell Douglas Aircraft since 1920 [6]

General characteristics
  • Crew: one
  • Length: 31 ft 2 in (9.5 m)
  • Wingspan: 47 ft 9½ in (14.57 m)
  • Height: 9 ft 0 in (2.74 m)
  • Wing area: 363 ft² (33.7 m²)
  • Empty weight: 4,119 lb (1,868 kg)
  • Loaded weight: 7,350 lb (3,334 kg)
  • Powerplant: 1 × Wright R-1820 Cylone 9-cylinder Radial, 710 hp (530 kW)



See also

Related development
Aircraft of comparable role, configuration and era


  1. ^ a b Smith 1986
  2. ^ a b c d Eden and Moeng 2002, pp. 74–77.
  3. ^ "The story of the 'Polar Star'." National Air and Space Museum. Retrieved: June 27, 2013.
  4. ^ "Fourteen Cylinder Motor In Hawke's New Plane", February 1933, Popular Science
  5. ^ Francillon 1979, p.153.
  6. ^ Francillon 1979, p. 154.
  • Eden, Paul and Soph Moeng. The Complete Encyclopedia of World Aircraft. London: Amber Books Ltd., 2002. ISBN 0-7607-3432-1.
  • Francillon, René J. McDonnell Douglas Aircraft since 1920. London:Putnam, 1979. ISBN 0-370-00050-1.
  • Smith, M.J. Jr. Passenger Airliners of the United States, 1926-1991. Missoula, Montana: Pictorial Histories Publishing Company, 1986. ISBN 0-933126-72-7.

External links

  • Northrop Gamma photographs/history
  • Northrop Gamma 2A, Sky Chief
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.