The Westmoore Propeller Company was one of a large number of companies, such as manufacturers of furniture and pianos, that participated in the World War I era, but apparently did not continue producing propellers for very long afterwards.
From its Accession Memorandum, this artifact was probably designed for the Hall-Scott A-5 engine.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.