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.
These 1917 propellers are a series of three showing the method of lamination. First is a group of seven pieces cut to their proper outlines for position in the assembly which they are to occupy. Second is the glued up blank with individual pieces in proper position. One blade is in the rough, and the other has been cut to the approximate the shape of half of the blade. Third is the finished two bladed propeller.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.