Читать книгу The Rise of the Flying Machine - Hugo Byttebier - Страница 13

France takes up the challenge

After Henson’s experiments, aviation in the UK was allowed to lapse but, curiously enough, interest in dynamic flight arose again in France, in spite of Navier’s calculations, which could have been forgotten in the meantime.

It is significant to note that Cayley was asked to contribute and he subsequently wrote several articles for the Bulletin Trimestriel of the first aeronautical society in the world, the Société Aérostatique et Météorologique de France, founded by a well-known French aeronaut J. F. Dupuis Delcourt. As will be noted, the title does not mention dynamic flight.

Yet Cayley, in 1853, proposed rather slyly that “As aerial navigation on the balloon principle, can only be carried out on an enormous scale of magnitude and expense ... it may not be unworthy of the Society to turn its attention towards making some cheap preliminary experiments to ascertain practically what can be done on the principle of the inclined plane, which appears to be applicable on any small scale from that of a bird to the uses of man, ... whenever a first mover, combining sufficient power, within a certain limit as to weight, is discovered.”

There is no evidence that directly links Cayley’s articles and proposals in this French Bulletin to the first attempts by Frenchmen to start experiments with fixed-wing aeroplanes, but the analogies are striking.

In 1857, a French naval officer, Félix du Temple, patented a fixed-wing flying machine moved by a motor. The machine was calculated to weigh one ton and du Temple, with more optimism than Cayley’s, estimated the power requirement as 6 hp.

Du Temple’s machine had a tail in the rear and a slight dihedral of the monoplane wing. One interesting original feature was the proposal that the aeroplane should take off by rolling across a field in the modern manner. Due consideration was also given to the question of stability.

Experiments were on small-scale models but, as soon as full-scale construction began around 1874, “the inadequacy of all motors known became apparent” as O. Chanute wrote. Du Temple had experimented with steam at high pressures and in due course designed an efficient boiler consisting of small water tubes as advocated by Cayley in 1809. This boiler produced no flight, but it was adopted by the French Navy, so du Temple was in some measure rewarded for his pains.

A second experimenter was Joseph Pline, a pioneer of great originality, who presented a patent in 1855 using a fixed plane in conjunction with a balloon, in an effort to get the best of both aeronautical systems. One interesting feature in this patent was that the fixed plane was for the first time designated with the word aéroplane.

Pline’s mixed system was not built; it would have been a failure as were all others that followed, trying to add wings to an airship, but Pline soon began to experiment with small flying models and stated that he was certain that it was possible for a plane to rise, sustain itself and fly around in the atmosphere without the use of hydrogen.

After carefully observing aerial currents as well as the organs used for flight by different animals (nature has produced more flying creatures than earthbound ones), Pline came to the conclusion that curved surfaces were the most efficient and he designed several paper models that had wings consisting of half-cylindrical surfaces arranged in the direction of flight, somewhat in the manner of F. M. Rogallo’s flexible wings designed in 1948.

Pline’s model aeroplanes flew gracefully and, under the name Papillons de Pline (Pline’s Butterflies), acquired great fame in France during the 1860s. All aeronautical experimenters were able to witness the flights of these flying models, which proved that in case of engine failure, a fixed-wing machine would not fall like a stone but could glide safely to earth.