Lycoming Operator's Manual Model 0-235-C Series Aviation Engines. No date but probably circa 1940s or 50s. Softcover. Illustrated.

The Lycoming O-235 is a family of four-cylinder, air-cooled, horizontally opposed, piston aircraft engines that produce 100 to 135 hp (75 to 101 kW), derived from the earlier 0-233 engine.

Well-known designs that use versions of the O-235 included the Cessna 152, Grumman American AA-1 series, Beechcraft Model 77 Skipper, Piper PA-38 Tomahawk, American Champion Citabria, Piper Clipper, and the Piper P-22 108 Colt.