The Rise of the Flying Machine. Hugo Byttebier

It was powered by a piston engine driven by compressed air and two contra-rotating propellers were placed in front of the wing.

      Tethered to a pole in the park of the official aeronautical establishment of Chalais-Meudon, it could progress only around a circular track. When the motor was started the machine accelerated rapidly and when it reached a speed of 8 m/s (18 mph) the plane rose. But the results were not sufficient to induce the backer to invest more money.

      Much time was then lost in finding another backer. One eventually materialized in the person of Charles Richet, who advanced 20,000 francs. This allowed Tatin to build a bigger model, powered by steam and weighing 33 kg (73 lbs). The wings covered 8 sq m (86 sq ft) so that the wing loading rose to 0.85 lb/sq ft and take-off speed rose appreciably. But the steam engine developed around 1 hp, and this appeared to be sufficient.

      The propellers worked in tandem, one at the front and one at the rear of the body. They ran in opposite directions so as to avoid any upsetting torque.

      The decision was taken to test the aeroplane over water, and the first experiment was undertaken in 1890 at Sainte Adresse on the Mediterranean coast. The plane started from a ramp before continuing on a horizontal path until flying speed was achieved. At 18 m/s (40 mph) the plane duly rose, but after a flight of about 60 m (300 ft) a construction defect caused it to crash on the rocks beneath the cliffs that formed the coastline.

      

      The plane was completely destroyed, but after much time and trouble it was eventually rebuilt. A second test was undertaken in 1896 at Carqueiranne, also on the coast, the engine giving about 25% more power.

      This time the Pénaud tail was not adjusted properly and after a flight of about 220 ft., it started to climb, stalled and fell into the sea. It was recovered and repaired and a third test was held in June 1897, but again, after a flight of 440 ft., the plane stalled due to a defect in balance and the succeeding crash ended the experiments.

      Meanwhile, Professor Langley had obtained better results in the United States and Richet decided to halt further work. Had Tatin been able to continue he would no doubt have succeeded in adjusting his plane for satisfactory flights, but it was not to be.

      When the experiments with full-size machines began, some ten years later, Tatin was around with advice and counsel, he wrote numerous articles and was probably instrumental in convincing several pioneers not to ignore Pénaud’s teachings at a time when another mode of flying had become preponderant.

      The evolution towards a practical aeroplane, which was started by Cayley and continued by Pénaud, was leading towards a stable and controllable flying machine that would be able to carry heavy loads over great distances at high speeds. In 1880, at the time of Pénaud’s death, it appeared that most of the problems had been solved and that the only impediment towards the final take-off was the powerplant, which was also felt to be within reach.

      

       The Birdmen Join the Fray

      Yet, after Pénaud’s death, the search for a way to achieve human flight took a new direction. This new avenue development aroused great interest partly because it turned the old beliefs, which had hitherto hampered progress, on their head.

      The old way of thinking maintained that it would be extremely difficult for man ever to achieve flight because the necessary power, as calculated by Borelli, Newton, Navier and others, seemed excessively high. Now, after keenly observing the flight of some bird species, it was argued that flight would become possible without power and indeed, as there was still no engine available, it was this new school that was finally to achieve the first human flight in history.

      The idea of flight without an engine harked back to a first, rather extraordinary, proposal made by Ferdinand Charles Honoré Philippe d’Esterno, Count d’Esterno. He was a gentleman of means who had studied the flight of birds on his own, and had subsequently published the results of his observations in a pamphlet that appeared in 1864 with the simple title Du vol des oiseaux (On the Flight of Birds).

      D’Esterno clearly set out the credo of those who wanted to emulate the effortless flight of some large birds when he stated that he could not understand what there was to “invent” in aeronautics “because flight had been known and practised since the creation of the world by thousands of millions of winged creatures”.

      From these thousands of millions, d’Esterno immediately discarded all but the very biggest soaring birds, mentioning the condor and the albatross as the examples that should be followed. Both these bird species had been observed to cover large distances in flight without once flapping their wings or exerting any other apparent effort and these two large birds were indeed to become the archetypes of ideal human flight for this new school of aeronautical devotees.

      D’Esterno and many more after him were convinced that other ways of achieving flight would be found and that the power needed would come from the wind, a statement that was thought to be self-evident. “We can derive from the wind, when it blows, an unlimited power and thus dispense with any artificial motor.”

      The difficulty in this proposition lay in that it was based on a fallacy. Newton’s third law of motion states that no action can be effected when there is no reaction opposing it. The wind can indeed develop considerable force; it can uproot trees and lift roofs from buildings, but it can do so only because trees are firmly anchored to the ground and roofs to the buildings. The wind also lifts a kite, as long as the kite is fixed to the ground by a line, and we have already noted how, by inverting this action, a few great minds visualized the theory of aeroplane flight; the reaction of the line had to become action (power) and the action of the wind (air on the move) had to become the reaction of the air upon the moving wing.

      The reality that eluded several of the searchers in the quest for soaring or powerless flight is that the air which supports the moving aeroplane wings cannot at the same time provide the power to move it. It was as one scientist in the nineteenth century saw it, “as if one expected that an inert body thrown into a river could find in the movement of the water a force capable of making it float upstream”. It was, in fact, another version of the age-old search for the “perpetuum mobile”.

      What, then, was the force that kept those birds from tumbling down to earth? Pénaud with his keen intellect found the solution and in a masterly article published in L’Aéronaute of March 1875 he explained that only ascending currents of air could arrest the inexorable downward movement of a bird that was soaring and when the bird was in reality falling, a rising current of air converted this into a flight that appeared to be horizontal. Soaring birds were able to follow a horizontal flightpath when the force of gravity was balanced by the force of the sun, the same sun that is responsible of all our sources of energy, excepting gravity. Pénaud’s explanation had already been anticipated by de Louvrié in 1866 and by others before him but many were the pioneers between 1880 and 1910 who expounded their own pet theory for explaining soaring flight. Some of them travelled to distant places in the world in order to observe the seemingly effortless flight of the majestic birds of prey. The fact that soaring was mostly achieved over deserts or near mountains should have given them a clue, as well as the circumstance that these birds only began their slow flight when the sun was overhead and that no soaring was done at night.

      One fact that d’Esterno clearly realized was that the wings of a soaring machine had to be as efficient as those of the birds he wanted to imitate, and he introduced one of the first proposals for the use of curved wings.

      It was equally obvious that to fly with the power of the wind entailed certain restrictions and complications. One restriction was that of size. A powerless machine evidently had to abandon all pretensions of ever becoming what Sir George Cayley had visualized as a “vehicle able to transport ourselves and our goods and chattels” as the modern airliner indeed has become. But d’Esterno was bold enough to envisage his soaring machine as an instrument of war able to observe, carry