EAA’s Attic — Menasco C-4S Pirate Engine

This piece originally ran in the May 2021 issue of EAA Sport Aviation magazine.

In 1936, as part of his ongoing quest for better performance, Steve Wittman replaced the original Cirrus Hermes engine in his well-known racer Chief Oshkosh with this Menasco C-4S Pirate. This inverted, four-cylinder inline engine was normally rated at 150 hp at 2260 rpm, but Steve ran it at 3000 rpm when racing, which meant a power output of about 200 hp. Menasco Pirate engines were also used in Great Lakes biplanes, Ryan STs, and a variant of the de Havilland Canada DH. 82C Tiger Moth known as the particular Menasco Moth.