What eventually became the Aeroproducts Propeller Company had its beginnings in 1935 as Engineering Projects, Inc. of Vandalia, Ohio. It was founded by two brilliant engineers, Werner J. Blanchard, who spent several years with the Curtiss Electric Propeller Company, and Charles. J. MacNeil.

Engineering Projects was bought by General Motors in 1940 for a speculated price in the $500,000 range and was re-named the Aeroproducts Division of GM. The company delivered only 73 of their novel "Unimatic" Aeroprop propellers in the month of December 1941, rising to 12,500 props in the month of February 1944. Aeroproducts evolved to become a Division of Allison in 1952, and eventually the propeller business was sold to Hamilton-Standard in 1990.

This artifact is one set of three blades from an experimental engine using a six-blade, two-stage contra-rotating propeller. The intended applications were for the Convair “Tradewind” flying boat and Convair XFY-1 “Pogo” vertical takeoff aircraft.