Northrop Gamma 2D
Single-engine one-place closed cabin low-wing landplane monoplane

Archive Photos

Northrop Gamma 2D, NC13757, c/n 8 (Northrop photo via Skytamer Archive)

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 2D (UC-100)

During 1934 three mail-carrying single-seat Gamma 2Ds (initially registered as X13757, X13758 and NR13759 respectively) were purchased by Transcontinental and Western Air. The aircraft were delivered on 30 April, 11 June and 18 July, 1934, and assigned fleet numbers TWA 16, 17 and 20 respectively. These aircraft were initially powered by 710-hp Wright SR-1820-F3 radials driving two blade propellers. The pilot’s cockpit, enclosed under a simplified sliding canopy, was located aft of the wing, and two cargo holds (combined capacity, 110 ft&ft3;; maximum payload, 139 lbs were provided in the fuselage forward of the cockpit.

The first Gamma 2D (s/n 8, NR13757) was used by TWA’s Jack Frye on 13-14 May 1934 to set a transcontinental one-stop record (Los Angeles-Kansas City-Newark in 11 hours 31 minutes) while carrying a payload comprising 335 pounds of mail and 85 pounds of express, and constituting the first consignment to be flown following resumption of air mail operations by the commercial carriers. This aircraft remained in TWA service for two years until sold in 1936 to Charles Babb, and aircraft broker. Apparently Babb needed to sell it to the Spanish Republican Government, but the deal did not materialize. Its subsequent fate is unclear, but apparently, the aircraft was sold in early 1942 to the US Corps of Engineers and, according to unconfirmed reports, was wrecked in Africa during World War II.

The second Gamma 2D (s/n 9, NR) had a more interesting career, as TWA modified it as an ‘Overweather Experimental Laboratory’ for research into problems which would be encountered by later airliners operating at high altitudes. For this purpose, the aircraft re-engine with a 775-hp SR-1820-F52 engine driving a three-blade propeller and fitted, under a three-way contract between TWA, General Electric and the Army Air Corps, with a GE Turbosupercharger. At the same time, the flight engineer’s station with a special set of 36 instruments was fitted in the cargo compartment. In this form, the aircraft was flown extensively for TWA by D.W. ‘Tommy’ Tomlinson with James Heistand as research engineer, until 11 October 1940, when it was sold to the Texas Company. Now powered by 735-hp SR-1820-F53 without the turbosupercharger, this Gama 2D was as assigned as Texaco No. 36 to Aubrey Keif, General Domestic Sales Department, for testing oil temperatures and flows. Two years later, on 15 October 1942, Texaco Sold the Aircraft to the Army Air Forces which designated it UC-100 in the utility transport category. On 17 January 1943, UC-100 (SF 42-94140) was damaged in a landing accident at Duncan Field, Texas. The aircraft was repaired and flown briefly. AF 42-9440 was finally surveyed at Kelly Field, Texas, 11 August 1943, due to a shortage of parts.

The third Gamma 2D (s/n 10, NR/NC13759) was none the less colorful as its predecessor. After being operated by TWA, beginning in July 1934, this aircraft was purchased by the Texas Company on 11 October 1935. Designated Texaco No. 20, the aircraft was assigned to Aubrey Keif for sales promotion in the northern United States and Canada. In December 1935, when Ellsworth and Hollick-Kenyon were believed lost in Antarctica, Texaco entrusted this Gamma 2D to Frank Hawks for a fast flight from the United States, via the West Coast of South America, to Antarctica. However, Ellsworth and Hollick-Kenyon were found before Frank Hawks arrived in Antarctica with his Gamma 2D and the aircraft was subsequently shipped Back to the United States. On 18 February 1937, the aircraft was sold to Frank Cordova in New York and delivered to Colonel Gustavo Leon in Mexico where it was registered as XA-ABJ. This however, was a cover for the ultimate destination of the aircraft as in December 1937 the Gamma 2D was shipped aboard the Spanish steamship SS Ibai. The aircraft was last reported in use as a bomber by the Spanish Republican forces, in which service it bore a code in the TG series.

Northrop Gamma Variants

Civil Variants

Military Variants

Northrop Gamma Operators 3

Military Operators

Civil Operators

Specifications — Northrop Gamma 2D Specifications and Performance Data
Grey, C.G. and Bridgeman, Leonard. Jane’s All The World’s Aircraft 1936, Sampson Low, Marston & Company, Ltd., London, 1936, pp. 299c-300c

Type

Wings

Fuselage

Tail Unit

Undercarriage

Power Plant

Accommodation

Dimensions

Weights and Loadings

Performance

References

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