American aeronautical engineer who designed the first successful air-cooled aircraft engine, used on many historic early flights.

After attending Yale University Lawrance joined a new automobile firm that was later ruined by the financial panic of 1907. He then went to Paris, where he studied architecture at the Beaux-Arts School and experimented with aeronautics at the Eiffel Laboratory, designing and building an 8-cylinder, 200-horsepower engine. He also designed a new type of wing section with an exceptionally good lift-to-drag ratio; the wing design was used widely in World War I.

Returning home in 1914, Lawrance continued his research, which culminated in the development of the engine later named the Wright Whirlwind by the Curtiss-Wright Company, of which he was chief of engineering. The Whirlwind, air-cooled with the aid of cooling fins on the cylinder heads, was improved in a succession of models for the U.S. Army and Navy and general aviation. By the mid-1920s its power and reliability had been demonstrated so effectively that a remarkable series of long-distance flights became possible: those of Admiral Byrd in the Arctic, that of Charles Lindbergh from New York City to Paris, and those of Amelia Earhart, Byrd, and Clarence Chamberlin across the Atlantic.

In 1930 Lawrance left Curtiss-Wright to form his own engineering firm, the Lawrance Engineering & Research Corporation, which, among other projects, built thousands of auxiliary electric-generating plants for World War II bombers.

Although the recipient of many honorary degrees and other distinctions, Lawrance remained relatively obscure despite the sensational publicity of the Lindbergh flight, an irony on which he commented, “Who remembers Paul Revere's horse?”