Lawrance J-1

J-1
Type	Piston aero engine
National origin	United States
Manufacturer	Lawrance Aero Engine Company

The Lawrance J-1 was an engine developed by Charles Lanier Lawrance and used in American aircraft in the early 1920s. It was a nine-cylinder, air-cooled radial design.

During World War I the Lawrance Aero Engine Company of New York City produced the crude opposed twins that powered the Penguin trainers, and the Lawrance L-1 60 hp Y-type radial.

After the end of World War I, the Lawrance engineers worked with both the Army and the Navy in developing their L-1 onto a nine-cylinder radial engine, which became the 200 hp Model J-1. It was the best American air-cooled engine at the time and passed its 50-hour test in 1922.

The U.S. Navy badly needed light, reliable engines for its carrierborne aircraft. As a means of pressuring Wright and other companies into developing radial engines, it gave a contract to Lawrance for 200 of the J-1 radial and ceased buying the liquid-cooled Wright-Hispano engines. At the urging of the Army and Navy the Wright Aeronautical Corporation bought the Lawrance Company, and subsequent engines were known as Wright radials. The Wright Whirlwind had essentially the same lower end (crankcase, cam, and crankshaft) as the J-1.

The New England Air Museum in Windsor Locks, Connecticut, has a Lawrance J-1 on display.

Data from A History of Aircraft Piston Engines

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