Charles Lawrance started designs for an air-cooled engine in 1915, designing his first 149 kW (200 hp) J-1 for a 1921 Navy contract. The Navy wanted a better engine for use on aircraft carriers, needing a compact lightweight engine not plagued with water leakage problems. After Lawrance’s company was absorbed by Wright Aeronautical in 1923, the J-1 progressed through stages, as the Whirlwind J-3, J-4, J-5, and J-6 series. Used in Lindbergh’s Spirit of St. Louis, the J-5 was the most famous.
The Wright J-4 incorporated improvements based on service with preceding models. J-4 engines powered such aircraft as the Fairchild FC-1 and FC-2, Fokker Universal, Laird Commercial LC-B200, Stearman C2B and C3B, and Stinson Detroiter SB-1.
This Wright J-4 engine was the first type of engine that Northwest Airlines used in its original Contract Air Mail and Passenger run between Minneapolis, Minnesota, and Chicago, Illinois, in October 1926 with a Stinson Detroiter four-place biplane.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
April 2, 1926
United States of America
PROPULSION-Reciprocating & Rotary
Lawrance Aero Engine Corp
Wright Aeronautical
Type: Reciprocating, 9 cylinders, radial, air cooled
Power rating: 149 kW (200 hp) at 1,800 rpm
Displacement: 12.9 L (788 cu in.)
Bore and Stroke: 114 mm (4.5 in.) x 140 mm (5.5 in.)
Weight: 218 kg (480 lb)
Diameter 111.8 cm (44.0 in.), Length 86.4 cm (34.0 in.)
A19650270000
Gift of Northwest Orient Airlines
National Air and Space Museum
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