Curtiss OX-5, V-8 Engine

More than 10,000 of these V-8 engines were manufactured, most of them for use in Curtiss JN-4 Jenny trainers. After World War I, thousands of OX-5s and Jennies were sold to the public at a fraction of their original cost to the government. In addition, during the 1920s, Waco, Laird, Curtiss, Fairchild, Alexander, Travel Air, and many other firms, developed airplanes powered by the OX-5 engine for civil aircraft.

The availability of a well-proven, inexpensive engine in such quantity was a mixed blessing -- it allowed many people to fly who could not afford a more expensive engine, but manufacturers of more modern power plants suffered.