Walter W. Everts of Baltimore, Maryland, invented this automatic pitch changing propeller with one blade and a counterweight. The counterweight is arranged to balance the moment generated by centrifugal force, and offset with respect to the axis of the blade in order to balance the moment generated by the traction force of the single-blade propeller. Combining their names, Everts and Frank Ellington founded the Everel Propeller Corporation. Manufacturing was done by the Sensenich Brothers of Lititz, Pennsylvania.
The air-worthiness of this unusual concept was demonstrated at Lancaster, Pennsylvania, beginning in 1937 with a Continental powered Cub aircraft, and followed with coast-to-coast flights and many other flight hours under all weather conditions. Type Certificates were received for the Taylor A and the J-2 Cub. Although tests with larger engines were accomplished, this concept was ultimately unsuccessful as a commercial venture because of an inability to compete with conventional propellers on the basis of cost and overall performance (e.g. weight).
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.