This four stroke OS FS-91 cutaway model airplane engine was Manufactured by O.S. Engines of Japan, in the 1980s. The partial cutaway of the cylinder block exposes the piston, crankshaft, and camshaft. Read our article a the founder of O.S. Engines, Mr. Shigeo Ogawa.

Exhibit added: August 1, 2011 - Last modified: January 5, 2023

Presented by The Joe Martin Foundation for Exceptional Craftsmanship