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.
This artifact is a spare American propeller from the Liberty engines that powered the airship Roma, purchased by the United States from the Italian government for $250,000 in 1921. It was the largest semi rigid airship in the world, and crashed during test flights in 1922.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.