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.
The artifact's shape indicates it is a Flexible Variable Pitch propeller. The manufacturer's brochure states: "These propellers are designed on the principle that the blade should constantly bend . . . accompanied by a torsional or twisting action by which the pitch would automatically change . . ." The description indicates they are for the U.S. Navy Curtiss NC-4 seaplane, the first aircraft to fly across the North Atlantic, an epic feat in 1919.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.