Career
He is remembered chiefly for his contributions to powered flight. Ellehammer"s later inventions included a successful triplane and helicopter. His helicopter was a coaxial machine.
Ellehammer later studied a disc-rotor configuration - a compound helicopter with coaxial blades that extended from the hub for hover, and retracted for high speed vertical flight.
Although a wind tunnel model was constructed, there"s no evidence that anything more was studied.