Vereinigte Deutsche Metallwerke, or United German Metalworks, was a society of medium-sized firms formed in 1930. One of VDM’s member companies, the Heddernheimer Metal Company, initiated the development of metal propellers in Germany by introducing a ground-adjustable propeller in the late 1920s, similar in construction to the American Standard Steel propeller.
VDM’s Dr. Hans Ebert later developed an ingenious method of pitch actuation using a reversible electric motor mounted on the engine crankcase. Actuation was via a flexible shaft connected to a small primary drive reduction gearbox, which was in turn attached to a large annular gearbox fitted to the rear of the propeller hub.
VDM production of constant-speed propellers began in 1938. VDM was the leading German manufacturer of metal propellers before and during World War II, utilized by approximately 90 percent of the Luftwaffe's front-line aircraft.
This artifact was donated simply to indicate the excellent design found in German propellers of World War II.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.