Jacob Christian Hansen Ellehammer (1871-1946) is known for his inventions of motorcycles, aircrafts and helicopters.

Jacob Christian Hansen Ellehammer was born and raised at Bakkebølle near Vordingborg. He was a skilled watchmaker but settled down in Copenhagen in 1898 as a self-employed mechanic. He produced machines for drinks, cigarettes, phonographs and much more.

Ellehammer is especially known for producing motorcycles and his experiments with aircrafts. In 1906, he succeeded, for the first time, in getting an aircraft to lift off the ground and fly 42 meters in a height of half a meter. However, the flight was not approved because it was not monitored by FAI (Fédération Aéronautique Internationale), and the plane was also tethered to the ground with a wire.

Ellehammer is also known for petrol and paraffin carburettor.