Danish flight pioneer

The Danish watchmaker Christian Hansen Ellehammer - born 150 years ago today - is not a name immediately associated with the history of aviation. However, the successful development of an early motorcycle brought him funds to indulge an interest in powered flight. He built the world’s first air-cooled radial engine, and other innovations - the triplane and helicopter - followed. Thanks to a diary-keeping cousin, we have first hand contemporary reports, albeit brief, of key moments in the testing of Ellehammer’s prototypes.

Ellehammer was born on 14 June 1871 in Bakkebølle, Denmark. He was apprenticed as a watchmaker, and then moved to Copenhagen where he worked as an electronics mechanic. In 1898, he established a company to produce electronic machinery. The first of his own successful design/inventions was a motorcycle called the ‘Elleham’ with the engine situated beneath the seating, similar in fact to the Vespa scooter 40 years later. This was a commercial success, and provided him with sufficient funds to experiment with powered flight. 

Using calculations derived from birds, Ellehammer developed an engine lightweight enough to lift himself in the air - this was the world’s first radial engine (with three cylinders). For the wings, he experimented with kites, finally arriving at a shape similar to hang gliders of the future. On 28 August 1906, Ellehammer’s cousin Lars recorded (in an old form of the Danish language) the first successful flight with a brief entry. Translated - and many thanks to Historic Wings for this information - it reads: ‘Tried with Ellehammer on board but without take off. Changed the engine timing with more preignition. Lifted off the ground then with Ellehammer on board we got momentarily off, making it 12 degrees [around the center pole].’

Two weeks later, on 12 September, they were trying again with an 18 hp engine (as opposed to the 9 hp used earlier). Lars’s diary: ‘Wind at 2-3 meters per second. Wind direction northeast.  Flew the whole way around. Hovered with the front and rear wheels [off the ground] traveling approximately [a distance of] 42 meters, reaching an altitude of 1 ½ feet high, as it came up against the [strong] wind.  Ellehammer was on board the whole time.  I took photos of it in flight . . .’

Ellehammer made over 200 flights from 1906 to 1909 in a tethered plane, all without serious accident. Step by step, he increased the engine power and refined the design, developing a monoplane, a semi-biplane and a helicopter. In 1908, he won a prize for an 11 second flight in front of Prince Henry of Prussia but, by this time, he was hearing news of more successful developments taking place in other countries. Nevertheless, he continued inventing, developing a special carburettor, a stationary air-cooled engine for airplanes, and a pump for fire extinguishers. Around 1920, he built a laboratory designed by a new firm of influential Danish architects. He died in 1946. In 1986, he was inducted into the International Air & Space Hall of Fame at the San Diego Air & Space Museum. There is very little biographical information about Ellehammer online in English other than at Wikipedia (see also an English translation of the Danish entry) and Historic Wings.