On loan from the Chicago Museum of Science and Industry
Charles L. Lawrance was an American aeronautical engineer who was an early proponent of air-cooled aircraft engines and founded the Lawrance Aero Engine Company in 1917. In 1923, the company was purchased by Wright Aeronautical as the U.S. Navy was concerned that Lawrance could not produce enough engines for the Navy's needs.
The L-4 was part of a series of small three-cylinder radial engines developed by Lawrance and was built from the early 1920's until the early 1930's. It is known to have powered the Sperry Messenger single-seat biplane and was also designed to be used in airships.
This engine is located in the Civilian Hangar under the left wing of the Lockheed 10A.