https://en.wikipedia.org/wiki/Northrop_Gamma

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.

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.


Role
Civil/Attack

Manufacturer
Northrop Corporation

Designer
Jack Northrop

Introduction
1932

Number built
60

Developed from
Northrop Alpha

Variants
Northrop YA-13

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. Twenty Five Gamma 2Es were
assembled in China from components provided by Northrop.

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.

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.

Specifications (Gamma 2D)

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)

Performance
Maximum speed: 223 mph (194 knots, 359 km/h) at 6,300 ft (1,920 m)
Cruise speed: 204 mph (177 knots, 328 km.h)
Range: 1,970 mi (1,713 NM, 3,170 km)
Service ceiling: 23,400 ft (7,130 m)
Rate of climb: 1,390 ft/min (7.1 m/s)
Wing loading: 20.2 lb/ft² (98.9 kg/m²)
Power/mass: 0.096 hp/lb (0.16 kW/kg)




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