2-839-524 - Heritage Art/Heritage Images

The J-5 Whirlwind was a cornerstone aviation technology of the 1920s and 1930s. Charles L. Lawrance began work on the J-series of compact, lightweight, air-cooled radials for the U.S. Navy in 1921. The Navy merged Lawrance's firm with Wright Aeronautical in 1923 to further develop and manufacture the new engines. The J-5 had such advanced features as sodium-cooled exhaust valves and aluminum cylinder heads designed by engine pioneer Sam D. Heron. The Whirlwind became the engine of choice for America's long-distance and exploratory fliers, including Charles Lindbergh, who chose a J-5 for the Spirit of St. Louis. This artifact, a military R-790-A, was the center engine on the Army Air Corps Fokker C-2 tri-motor “Question Mark,” which pioneered aerial refueling by setting an endurance record of 150 hours and 40 minutes over Los Angeles in 1929.