Northrop Gamma 2L
Single-engine two-crew low-wing flying-test-bed monoplane

Archive Photos

Northrop Gamma 2L, (G-AFBT, c/n 347) (Northrop/Douglas photo via the John Shupek Collection)

Overview — Northrop Gamma Series

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 a light bomber.

Design and Development — The Northrop 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 Northrop Alphas, the fixed landing gear was covered in distinctive aerodynamic spats, and the aircraft introduced a fully enclosed cockpit.

Operational History — The Northrop Gamma saw fairly limited civilian service as mail planes with Trans World Airlines, but had an illustrious career as 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 Nomad light attack aircraft. Military versions of the Northrop Gamma saw combat with Chinese and Spanish Republican air forces. Twenty Five Northrop Gamma 2Es were assembled in China from components provided by Northrop.

On June 2, 1933 Frank Hawks flew his Northrop Gamma 2A Texaco 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 Northrop Gamma 2G making the west-east transcontinental run in 9 hours, 26 minutes, and 10 seconds.

The most famous Northrop Gamma was the Northrop Gamma 2B Polar Star. The aircraft was carried via ship and off-loaded onto the pack ice in the Ross Sea during Lincoln Ellsworth’s 1934 expedition to Antarctica. The Northrop Gamma 2B was almost lost when the ice underneath it broke and it had to be returned to United States for repairs. The Northrop Gamma 2B Polar Star’s second return 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. The Northrop Gamma 2B Polar Star was later recovered and donated to the Smithsonian National Air and Space Museum where it resides to this day.

Overview — Northrop Gamma 2L

The last Northrop Gamma was specialty built for the Bristol Aeroplane Company in the UK, for use as a flying test-bed for the new fourteen-cylinder sleeve-valve Hercules engine. The aircraft was delivered without engine on 4 June 1937, and a registered G-AFBT to the British Air Ministry, London, England on 6/4/1937 under export certificate #E-2802 of 6/2/1937. The Northrop Gamma 2L (c/n 347) was initially fitted with a 1,290-hp Bristol Hercules Mk.1SM driving a three-blade propeller and tested at Filton, Bristol, England. With this engine, the aircraft made its first flight at Filton, Bristol, during September 1937. Later, the Northrop Gamma 2L was used to test the Hercules Mk.1M(a), Mk.3SM, and Mk.6SM engines. Externally, the Northrop Gamma 2L was easily recognizable because of the characteristic Bristol exhaust collector ring in the forward portion of the cowling and the fixed undercarriage and vertical tail services similar to those of the Northrop A-17 Nomad. The pilot and flight engineer sat in tandem, with the pilot above the wing, under a canopy fairing into the rear fuselage. The aircraft was dismantled at Filton during World War II and scrapped in January 1946.

Northrop Gamma Variants

Civil Variants

• Northrop Gamma 1E: Single-engine (Pratt & Whitney Hornet) two-seat closed-cabin low-wing land monoplane, 1 built, Sweden A.B Aerotransport, c/n 29.
• Northrop Gamma 2A: Single-engine (Wright Whirlwind) single-seat closed-cabin low-wing land monoplane, 1 built, Texaco Sky Chief, c/n 1.
• Northrop Gamma 2B: Single-engine (Pratt & Whitney Wasp) two-seat closed-cabin low-wing land monoplane, 1 built, Ellsworth Polar Star, c/n 2.
• Northrop Gamma 2C: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, 1 built, USAAC light attack aircraft YA-13, c/n 5.
• Northrop Gamma 2D: Single-engine (Wright Cyclone) single-seat closed-cabin low-wing land monoplane, 3 built, TWA cargo aircraft, c/n 8-10.
• Northrop Gamma 2E: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, light attack bomber, Chinese Military, c/n 14, c/n 46, c/n 48-72.
• Northrop Gamma 2EC: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, light attack bomber, Chinese Military, c/n 17-22, c/n 45.
• Northrop Gamma 2ED: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, light attack bomber, Chinese Military, c/n 15-16, c/n 23-27, c/n 30-37.
• Northrop Gamma 2ED-C: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, shipped to USSR, c/n 47.
• Northrop Gamma 2F: Single-engine (Pratt & Whitney R-1870-7) two-seat closed-cabin low-wing land monoplane, 1 built, USAAC light attack aircraft XA-16, c/n 5.
• Northrop Gamma 2G: Single-engine (Curtiss Conqueror) two-seat closed-cabin low-wing racing land monoplane, 1 built, Jacqueline Cochran, c/n 11.
• Northrop Gamma 2H: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing racing land monoplane, 1 built for Marron Price Guggengeim, flown by Russell W. Thaw, c/n 12.
• Northrop Gamma 2J: Single-engine (Pratt & Whitney Wasp) three-seat closed-cabin low-wing land monoplane advanced trainer, 1 prototype built, USAAC advanced trainer competition, version of Army A-17 Nomad, c/n 186
• Northrop Gamma 2L: Single-engine (delivered without engine) two-seat closed-cabin low-wing land monoplane, 1 built, sold to Bristol Aeroplane Company for Hercules engine testing, c/n 347.
• Northrop Gamma 3A: Single-engine (Pratt & Whitney Wasp) single-seat closed-cabin low-wing land monoplane fighter, 1 built, USAAC XP-948, c/n 44.
• Northrop Gamma 5A: Single-engine (Pratt & Whitney Wasp) two-seat closed-cabin low-wing land monoplane, 1 built, exported to Japanese Navy 1935, c/n 187.
• Northrop Gamma 5B: Single-engine (Pratt & Whitney Twin Wasp, Jr.) two-seat closed-cabin low-wing land monoplane, 1 built, Spanish Republican Air Force, c/n 188.
• Northrop Gamma 5D: Single-engine (Pratt & Whitney S3H-1) two-seat closed-cabin low-wing land monoplane, 1 built, exported to Japanese Navy, c/n 291.

Military Variants

• Northrop YA-13: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, 1 built, USAAC light attack aircraft, Gamma 2C (A.C. 34-027, c/n 5).
• Northrop XA-16: Single-engine (Pratt & Whitney R-1870-7) two-seat closed-cabin low-wing land monoplane, USAAC light attack aircraft, redesigned & re-engine YA-13 (A.C. 34-027, c/n 5).
• Northrop XP-948: Single-engine (Pratt & Whitney R-1870-7) single-seat closed-cabin low-wing land monoplane, 1 built, aka Northrop 3A, USAAC pursuit adaptation of Navy XBT-1 (c/n 44).
• Northrop XFT-1: Single-engine (Wright XR-1510-8) single-seat closed-cabin low-wing land monoplane, 1 built, USN experimental fighter (BuNo 9400, c/n 6).
• Northrop XFT-2: Single-engine (Wright R-1535-72 single-seat closed-cabin low-wing land monoplane, re-designed and re-engine XFT-1, 1 converted, USN experimental fighter (BuNo 9400, c/n 6).
• Northrop A-17: Single-engine (Pratt & Whitney R-1535-11 Twin Wasp, Jr.) two-seat closed-cabin low-wing land monoplane with fixed landing gear, 109 built, USAAC light attack bomber (A.C. 35-051 to 35-160, c/n 75-184).
• Northrop A-17A: Single-engine (Pratt & Whitney Twin Wasp, Jr.) two-seat closed-cabin low-wing land monoplane with retractable gear, 129 built, USAAC light attack aircraft (A.C 36-162 to 36-261, 38-327 to 38-377).
• Northrop A-17AS: Single-engine (Pratt & Whitney R-130-41 Wasp) three-seat closed-cabin low-wing land monoplane with retractable gear, 2 built, USAAC staff transport (A.C 36-349 and A.C. 36-360, c/n 289-290).
• Northrop XBT-1: Single-engine (Pratt & Whitney R-1535-66) two-seat closed-cabin low-wing land monoplane, 1 built, USN experimental dive-bomber (BuNo 9745, c/n 43).
• Northrop BT-1: Single-engine (Pratt & Whitney R-1534-94) two-seat closed-cabin low-wing land monoplane, 54 built, USN dive-bomber (BuNo 0590 to 0626, 0628 to 0643, c/n 293 to 329, 331 to 346).

Northrop Gamma Operators ²

Military Operators

• China
• Japan: as BXN
• Spain: Spanish Republican Air Force - Northrop 2D and 5B Gamma
• United States: United States Army Air Corps

Civil Operators

• Manchuria: Manchukuo Manchurian Air Lines
• United States: Trans World Airlines

Northrop Gamma 2L Specifications and Performance Data

Type

• Single-engine two-crew low-wing flying-test-bed monoplane

Power Plant

• 1,290-hp Bristol Hercules Mk.1SM driving a three-blade propeller

Dimensions

• Wingspan: no data inches
• Length: no data
• Height: no data
• Wing area: no data

Weights and Loadings

• Weight empty: no data
• Weight loaded: no data

Performance

• Maximum speed: no data
• Cruising speed: no data
• Landing speed: no data
• Initial rate of climb: no data
• Service ceiling: no data
• Cruising range: no data

References

• Photo: Northrop Gamma 2H via the John Shupek Collection
• Wikipedia: Northrop Gamma
• Allen, Richard Sanders, The Northrop Story 1929-1939, Orion Books, New York, 1990, ISBN 0-517-56677-X, pp. 138, 150-155.
• Francillon, René J., McDonnell Douglas Aircraft since 1920: Volume I, Putnam Aeronautical Books, London, 1995, ISBN 0-85177-827-5, pp. 127-138.