"THE HELICOPTER HAS LESS STABILITY THAN THE AEROPLANE… IN CASE OF THE ENGINE STOPPING THE MACHINE HAS NO MEANS OF GLIDING SAFELY TO EARTH": FIRST EDITION OF PORTER'S THE HELICOPTER FLYING-MACHINE, 1911

PORTER, J. Robertson. The Helicopter Flying-Machine. London: Offices of "Aeronautics", 1911. Slim octavo, original gilt-stamped burgundy cloth; pp. 80. $1750.

First edition of this examination and comparative analysis of non-airplane flying machines including the helicopter and the turbine machine.

This important early work examines helicopter design, decades before helicopters were in common use. Porter was a British engineer who patented a control system for use in a rotary aircraft. While Porter's invention never made it into practical use, he did demonstrate a machine using similar technology, the "Porter Gyropachute," at the 1913 Olympia Air Show. "In The Helicopter Flying Machine, Mr. J. R. Porter, who has devoted many years to the study of the subject, rejects the helicopter proper for what he terms a 'turbine machine.' The propellers in this apparatus are designed to produce a horizontal and radial current of air, which is diverted downwards by means of curved annular surfaces, with the result that an upward reaction is produced. It is his opinion that a helicopter proper 'has less stability than the aeroplane'" (contemporary review, Nature).

Interior generally fine with toning to endpapers, a few faint stains and toning to cloth extremities. An extremely good copy.