The Rise of the Flying Machine. Hugo Byttebier
opposition to Pénaud’s theories, can hardly be termed to have been positive.
Further Progress on the Powerplant
Whilst a new school of pioneers were beginning to dream of flight without power, the aircraft engine was progressing with giant strides.
The German engineer Nikolaus Otto’s success in making a smooth-running four-stroke engine has been discussed above. The Otto engine was much too heavy to serve on aircraft, which needed a powerplant along the lines of Ponton d’Amécourt memorable words of 1864: “What is needed for the conquest of the air is a horse in a watch-case”.
Jules Armengaud, an eminent engineer of that time, discussing the new Otto engine in the January 1878 issue of L’Aéronaute arrived at the conclusion that in order to become light, gas engines would have to reach a high rate of revolutions. It was a perfectly logical conclusion and the way towards the high-speed engine was opened shortly afterwards by Gottlieb Daimler, a manager of the Deutz Company.
Daimler was a fiery character continually at loggerheads with his colleague Nikolaus Otto and for that reason he had seen his contract with Deutz repealed in June 1882.
Daimler lost no time in persuading another first class engineer, Wilhelm Maybach, to leave Deutz as well, and together they worked out a way to create a small high-speed four-stroke engine and actually had one running at 600 rpm by the end of 1883.
The first little Daimler engines weighed less than 100 kg per hp and the possibility of using them for road vehicles was at once considered. They were not yet horses in a watch-case, but that ideal was nearer. In 1885 a motorcycle was built, followed by a car in 1886, as every student of automotive history knows.
Finally, in 1888 after a fruitless approach to the Prussian Airship Battalion, Daimler was able to sell the first aerial engine to work with internal combustion to Karl Woelfert, a Leipzig bookseller and aeronautical fanatic, who installed a 2 hp Daimler engine in a dirigible balloon. The first attempt was a failure because the airship did not rise nor was it dirigible, but a first attempt had been made.
The Dirigible Parachute
1884 was another important year in the evolution towards the conquest of the air. The early 1880s had seen a renewed interest in soaring flight and in 1883 de La Landelle, the indefatigable aeronautical visionary who had coined the word “aviation”, indicated that the “experimental study of aero-dynamics (l’aéro-dynamique) would constitute a new science” as indeed it did and still does.
In 1884, de La Landelle proposed yet another variant among the possibilities of achieving human flight. The classical concept had been to accelerate a winged vehicle by using a mechanical powerplant until flying speed was reached, but the powerplant was long in coming. Then it appeared that the power of the wind would provide the solution and this led to the theories about soaring flight that were being debated at that time.
What de La Landelle now suggested was the use of gravity as a source of power. Flight had always been considered as the conquest of gravity and now gravity was proposed as a means to conquer itself, as it were. The concept seemed a bit outlandish but de La Landelle was right because soaring uses gravity as the primary source of power.
In an article in L’Aéronaute of July 1884, de La Landelle pointed to the parachute — a very old concept which had already been studied by Leonardo da Vinci — that could be used for flying experiments. He referred to the already functional parachute Garnerin had used in 1797 and which Garnerin’s niece Elisa had learned to manipulate in such a way that she could direct its descent and, as de La Landelle explained, had thereby turned her parachute into a glider. “Together with the kite” wrote de La Landelle, “the instrument that the aviation school should study can be condensed into two words, ‘dirigible parachute’.”
De La Landelle envisaged a sort of combination of kite and parachute, which meant a kind of weighted kite like the one Cayley had already experimented with. De La Landelle thought that, by using a dirigible parachute, a simple way could be found to control a glider in flight. This was not at all a foolish idea; it was taken up in earnest five years later and led to the first flying experiments with full-sized machines.
A second pioneer to come up with a new proposal was de Louvrié, who in 1866 had already indicated his belief in the possibility of fixed-wing flight and was now thinking about wheeled undercarriages, large airfields and a low frontal area of the body to reduce drag.
In May 1884 he published an article describing a soaring glider with an articulated tail that, in his opinion, would stabilize the glider’s flightpath. He still believed in the power of the wind as a propelling force but otherwise his ideas were following correct lines.
Meanwhile in England a newcomer, Horatio Phillips, applied for patents on a whole series of curved wing-shapes on which he had done actual experiments in “artificial currents of air”, a precursor of the modern wind tunnel. He had found that a suitably curved wing could lift twice as much as a flat surface, hence his patent applications. Later (in 1890) he patented an aeroplane that was to use a series of superposed curved wings in the manner of the venetian blind. A small model, fitted with forty of the specified wings totalling 136 sq ft and powered by a steam engine of 200 lbs, was tethered to a central pole and driven along a circular track, just as Tatin had done in 1879.
In May 1893 Phillips’ model aeroplane was tested, but the total weight of the apparatus amounted to 330 lbs and the engine was obviously not powerful enough, so that a complete take-off was not achieved in spite of the efficient wing-shapes.
Alexandre Goupil
One of the most able pioneers of that year was Alexandre Goupil. In an article published in July he too referred to the theme of the dirigible parachute. He stated that, contrary to some preconceived ideas, an aeroplane, when the engine stopped or failed, would not fall but would turn into a dirigible parachute. This is perfectly true, because aeroplanes, if they do not break up in the air, do not fall and if the engine fails, gravity takes over and the aeroplane becomes a glider as long as the pilot is able to control the descent by maintaining a flying speed above the minimum necessary for sustentation.
Goupil had gone thoroughly into the study of the fixed-wing aeroplane. He had experimented with a sort of kite weighing 50 kg (110 lbs) with a surface of 290 sq ft held against a wind of 6 m/s (14 mph) at an angle of 10 degrees, this kite was able to lift two men but at greater wind-speed the apparatus became uncontrollable and broke up.
Goupil had studied Mouillard’s book and was confident that the problems relating to human flight could be solved. But he was convinced that some form of mechanical power was needed and he designed a light steam engine which was calculated to develop 15 hp for a weight of 638 lbs.
The results of his studies and observations were condensed into a small book entitled La Locomotion aérienne, published in 1884, which is remarkable for the many solutions it provided to the difficulties that continued to beset the flight of a practical aeroplane.
In his book Goupil formulated a theory of flight and arrived at the same conclusions as Phillips, that a curved wing was the most efficient shape. He also explained that lift was obtained by the rarefaction of air above the wing, more than by the pressure built up under the wing. But whereas Philips’ conclusions were the result of experimental work, those of Goupil, like those of many French scientists, were based on mathematical theories.
It was clear to Goupil that fixed-wing aeroplanes would need large fields “devoid of trees” because the angle of climb after take-off would be small; and an aeroplane would have to take off heading into the wind. All this was close to the realities of human flight and nobody will argue about the need for large airfields today.
Goupil’s aeroplane project was to be made laterally stable by a dihedral angle of the wing, as Cayley had already proposed, but due to the influence of Mouillard, no attention was paid to longitudinal stability as