Model Flying Machines

1853 Cayley Improved Helicopter Model

In 1853, Sir George Cayley wrote a paper for "Bulletin Trimestriel", a French aeronautical journal, and included the following description of a helicopter model. Unfortunately, the journal folded before Sir George's paper could be published. The extract has been slightly abridged for this website.

"When perfected this toy helicopter furnishes a very beautiful specimen of the action of the screw propeller in the air.
The figures show the form of one, in its full scale that will mount for sixty or eighty feet perpendicularly, and when directed obliquely upward in a angle of about 23 degrees with the ground, its flight will be nearly horizontal for a considerable distance: and then, by the flyers [ie the blades] losing a portion of their propelling power, the constant gravitation of the spindle gradually prevails, and directs the flight upwards in a very graceul curve, till the movement is extinct.

These flyers are made of tinned iron, of medium thickness, sharpened or bevelled off at the top of the advancing edge, and placed, for their whole length at an angle of 15 dgrees with the plane of rotation.

The stem is turned in boxwood and the flyers secured by a screw nut of the same material. The whole weighs 192 grains [12.5gm]. A slender silk cord of about a yard in length will give the velocity required."

Although not specifically mentioned in the extract, each blade on the model measured 4.3cm long by 1.8cm wide. All remaining dimensions of the model can be derived from those values.

The source of this material is the book "Sir George Cayley's Aeronautics 1796-1855" by Charles Gibbs-Smith, published by Her Majesty's Stationery Office, London, UK, in 1962. Copies of the book may be found at www.bookfinder.com.

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