This unique model airplane engine is an OS 49-PI Type II Wankel engine. The Wankel engine was designed by Felix Wankel, and was used early on in pumps before being applied to auto engines. In 1970, the OS engine company, in conjunction with the German model building company Graupner, developed the first Wankel for use in model airplane flying.

Engine specifications—

Carburetor: #21G

Power Output: 1.27 bhp at 17,000 rpm

Weight: 335g (11.8oz)

Practical rpm: 2,500-18,000 rpm

Crankshaft thread: 1/4-28

Propeller: 9×6-7, 10×4-6 or 11×4-5

Exhibit added: June 11, 2010 - Last modified: November 2, 2023

Presented by The Joe Martin Foundation for Exceptional Craftsmanship