Planes of Fame Air Museum
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Home »  Collection »  Flying & Static Aircraft »  Northrop Alpha 4A


  • John K. Northrop formed his first aircraft company in the late 1920s following a stint as a designer at Lockheed, where he had worked on the famous Vega. Northrop's first project was the Alpha, designed to carry mail and passengers from coast to coast. The passengers sat comfortably inside the cabin. However, at the time, pilots believed that they must be exposed to the elements, so the pilot sat above and behind the cabin in an open cockpit.
  • The Alpha was an extremely advanced design for its day. It was the first all-metal airplane, incorporating multi- cellular wing construction and a semi-monocoque fuselage. Aerodynamic improvements included the use of wing fillets and an NACA streamlined cowling. It also incorporated radio navigation equipment and rubber deicing boots on the leading edges of the wings and tail surfaces, allowing it to fly at night and through all weather. All of these features were later incorporated into the Douglas DC-3.
  • Northrop produced 17 Alphas in 1930-31. Fourteen of these were purchased by Transcontinental and Western Air (TWA) and operated on the San Francisco-to-New York route, beginning in April 1931. These were phased out of service in 1935 with the advent of larger twin-engined transports. Three Alphas, designated C-19s, were operated by the USAAC from 1931 to 1939.



  • Planes of Fame Air Museum's Alpha is one of only two known to survive. Parts of our airplane were used to restore the other, which hangs in the Transport Gallery of the Smithsonian Institution's National Air and Space Museum in Washington, D.C. (color photo above is not of the museum's aircraft).
  • This black & white photo was taken on February 13, 1931 and is Planes of Fame Air Museum's Northrop Alpha NC999Y.



Status: Restoring to Static Display
Manufacturer: Northrop Aircraft Corporation
Year: 1931
Model: Alpha 4A
Registration Number: NC999Y
Serial Number: 
Crew: 1
Max T/O Weight: 4,700 lb.
Span: 41 ft. 10 in.
Length: 28 ft. 5 in.
Height: 9 ft. 0 in.
Maximum Speed: 177 mph
Cruise Speed: 145 mph
Rate of Climb: 1,000 ft/min
Power Plant: 1 × Pratt & Whitney R-1340-SC1 Wasp 9-cylinder air-cooled radial engine, 420 hp
Range: 1,650 miles
Service Ceiling: 19,300 ft.
Armament: None


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