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.

The manufacturer's brochure noted: "Considerable quantities of the 'solid' [four-bladed] type were made by us for British machines in 1916 . . . Our Signal Corps also used a few of them . . . During the war we made many thousands of the double two-bladed type for use on Navy machines. Four-bladed propellers have a useful field where the diameter is greatly restricted and large power must be transmitted with small 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.