Lycoming XO-435-7, Horizontally-Opposed 6 Engine

Lycoming traces its beginning to a mid-nineteenth century sewing machine manufacturer. In 1907 that company was sold and restructured as the Lycoming Foundry and Machine Company, which produced automobile engines, and later was a subsidiary of the Auburn Auto Company. Although its early aircraft engines were radials, Lycoming entered the light-aircraft engine field early in 1938 with the introduction of the air-cooled, four-cylinder, horizontally opposed O-145 engine.

Along with Continental and Franklin, Lycoming was a basic provider of engines for the ubiquitous bright yellow Piper Cub, synonymous with small general aviation aircraft for many years. Most recently Lycoming became a subsidiary of Textron Inc.

Designed to operate in a vertical position, the XO-435-7 powered the Sikorsky XH-6 and H-6B helicopters. A shaft-driven fan ducted cooling air through a wrap-around engine cowling. Models of the O-435 powered aircraft such as the Vultee-Stinson L-5 and O-62 and Fleetwings XBQ-2 and PQ-12A.