2-839-517 - Heritage Art/Heritage Images

The Union Gas Engine Company (later the Union Diesel Engine Company) of Oakland, California designed this aircraft engine in 1915. In 1917, it was the first to pass the U.S. government 50-hour test. Union engines were built primarily for use in lighter-than-air craft, and an engine of this type powered the trans-Atlantic trial and record flight of the U.S. Navy’s Airship C-5 in 1919.