Northrop Gamma 2B Polar Star

Northrop Gamma 2B Polar Star
Single engine two-seat all-metal low-wing monoplane for Antarctic exploration

Archive Photos

Northrop Gamma 2A (3-view drawing by Skytamer.com)

Northrop Gamma 2B "Polar Star" on display at the National Air and Space Museum (Photos via Wikipedia)

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 2B — Polar Star

The Northrop Gamma 2B was under development and construction at the same time as the Northrop Gamma 2A — Texaco’s Sky Chief. It was a similar specially designed aircraft to fit the requirements of the Antarctic explorer Lincoln Ellsworth. The Northrop Gamma 2B (c/n 2) was a single-engine (500-hp Pratt & Whitney Wasp SD-1 #4810), two-place, tandem-seat, low-wing monoplane. The aircraft received its experimental X license (NX12269) on 22 August 1932 and was licensed to the Northrop Corporation, Inglewood, CA. The restricted R license (NR12269) was granted on 14 November 1932. The aircraft was restricted for polar explorations.

The Northrop Gamma 2B was the first Northrop Gamma to be test-flown. The delivery date was November 1932. It was sold on 14 February 1933 to Lincoln Ellsworth, New York City, New York. The price of the aircraft was $37,000. Lincoln Ellsworth named the aircraft the Polar Star.

The Polar Star was taken to the Antarctic in January of 1934 and test-flown on skis by Bernt Balchen. It was damaged in an unseasonal ice breakup and was returned to the Northrop factory for repairs and test flying on floats. The Polar Star returned to the Antarctic during the winter of 1934-35 and made one flight. The Polar Star returned again to the Antarctic in the fall of 1935. Ellsworth, piloted by Herbert Hollick-Kenyon, made a trans-Antarctic flight from Dundee Island to close to Little America between 23 November and December 9, 1935, with five stops in route. The Polar Star returned to the United States and was presented to the Smithsonian Institution in Washington DC on 25 April 1936. It is currently part of the National Air and Space Museum’s collection in Washington DC. It is the only Northrop Gamma in existence.

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

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

Specifications — Northrop Gamma 2B — Polar Star

Registration: NX12269, NR12269
C/n: 2
Manufactured: 8/1932
Crew: 2
Wing span: 48 feet, 0 inches
Length: 29 feet, 9 inches
Wing area: 363 ft²
Empty weight: 3,200-3,400 lbs
Loaded weight: 7,100 lbs
Powerplant: 500-hp Pratt & Whitney Wasp SD-1 #4810 nine-cylinder radial engine
Comments: Lincoln Ellsworth’s "Polar Star" is currently on display in the National Air & Space Museum.

References

Northrop Gamma 2B photos via Wikipedia
Francillon, René J., McDonnell Douglas Aircraft since 1920: Volume I, Putnam Aeronautical Books, London, 1995, ISBN 0 85177 827 5, pp. 127-138
Allen, Richard Sanders, The Northrop Story 1929-1939, Orion Books, New York, 1990, ISBN 0-517-56677-X, pp. 138, 150-155.
Aeronautical Chamber of Commerce of America, Inc., The Aircraft Year Book For 1935, Aeronautical Chamber of Commerce of America, Inc., New York, 1935, pp. 348