When Orville Wright moved to Oakwood, Ohio in 1914, he became acquainted with his neighbor, George Hartzell. George's son, Robert, had a strong interest in aviation and was encouraged by Orville to begin making propellers at his father's walnut wood products business. Robert left the University of Cincinnati in 1917 to begin the propeller venture. The United States had just entered World War I and the war effort created an instant and almost unmanageable demand for Hartzell Walnut Propellers. Hartzell supplied propellers to nearby Dayton-Wright Airplane Company, as well as Glen Curtiss' company and other early aviation pioneers. Hartzell has continued to supply propellers with advancing technology into the twenty first century.
This device is a test club, resembling a propeller and designed to be mounted on an aircraft engine shaft to absorb engine power during test or run-in, and usually to provide some airflow for engine cooling purposes.