__NOTOC__ The Ellehammer helicopter was an otherwise-unnamed experimental aircraft built in Denmark in 1912. Based on experiments with models,

Jacob Ellehammer Jacob Christian Hansen-Ellehammer (14 June 1871 – 20 May 1946) was a Danish watchmaker and inventor born in Bakkebølle, Denmark. He is remembered chiefly for his contributions to powered flight. Following the end of his apprenticeship as a ...

constructed a full-size machine equipped with two contra-rotating discs, each of which was fitted with six vanes around its circumference. The pitch of these vanes could be varied in operation by the pilot, an early example of cyclic control. The same engine that drove the rotors also powered a propeller mounted tractor-wise to the aircraft's frame. Ellehammer 1935

After a number of indoor tests, the aircraft was demonstrated outdoors and made a number of free take-offs. One of these trials was witnessed by

Prince Axel of Denmark Prince Axel of Denmark, ( Danish: ''Prins Axel Christian Georg til Danmark''; 12 August 1888 – 14 July 1964) was a member of the Danish royal family. He was the second son of Prince Valdemar of Denmark and Princess Marie of Orléans, and a gr ...

. Experiments with the helicopter continued until September 1916, when it tipped over during take-off, destroying its rotors. A famous photo shows it hovering in 1914, though there is no evidence that it was successful in achieving translational flight. 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.

Specifications

References

* * * {{Ellehammer aircraft 1910s Danish experimental aircraft

Helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...

1910s Danish helicopters Coaxial rotor helicopters Single-engined piston helicopters