An early predominant manufacturer in the United States, Spencer Heath's American Propeller and Manufacturing Company opened in Baltimore in 1909. Heath was first to use machines for mass production of aircraft propellers and, under the Paragon trademark, these were widely used in World War I. Like most propellers of that era, construction was a wood laminate because of light weight, strength, fabrication ease, and resistance to fatigue in a vibrating and flexing environment.
Heath demonstrated the first "engine-powered, engine-controlled, variable and reversible pitch propeller" in 1919, but was unsuccessful in convincing the Army of the practicality of the concept. He sold the company to the Bendix Corporation in 1929 and retired from aeronautics two years later.
From a marking on this artifact, the propeller is apparently of the "monoid" type.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.