An early predominant manufacturer in the United States, Spencer Heath's American Propeller and Manufacturing Company was first to use machines for mass production of aircraft propellers. Under the Paragon trademark, these were widely used in World War I. First made in 1909, the manufacturer's brochure noted: "Three-bladed Paragons have nearly always given better results than two-bladed propellers of any type." They served with the Navy and Army Signal Corps.
Heath's rationale was: "Where the power is large or the propeller speed is low the propeller must of necessity have very high pitch in relation to diameter. In such cases the three-bladed propeller should be preferred in order to use a lower pitch without increasing the diameter."
Later unsuccessful in convincing the Army of the practicality of a variable pitch concept, Heath sold the company to the Bendix Corporation in 1929, and retired from aeronautics two years later.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.