The Rise of the Flying Machine

L. P. Mouillard

A few months after Pénaud had sent his resignation to the Société Française de Navigation Aérienne, they received a letter from Louis Pierre Mouillard who explained that in the flight of a flapping bird its tail was of no use. This was a rather unusual statement and Mouillard ended his letter by stating: “If I were rich, I would like to solve the aerial problem in three years.”

Mouillard had become a fanatical devotee of soaring flight as achieved by the big birds of prey, which he had studied first in Algeria and later in Egypt, where he worked in Cairo. During his stay in these subtropical countries he had assigned himself the formidable task of analysing, measuring and describing all the birds he could lay his hands on and had finally come to the same conclusion as d’Esterno, that man would be able to fly with the power of the wind.

In 1881, Mouillard published a remarkable book with the suggestive title of L’Empire de l’air, that caused quite a stir because his belief in the possibility of soaring flight was strongly expressed: “Ascension is the result of the skilful use of the power of the wind and no other force is required.”

Hureau de Villeneuve wrote a long appraisal of Mouillard’s book in the October 1881 issue of L’Aéronaute, analysing the concept of soaring flight which had baffled so many researchers. In his review he rejected Pénaud’s theories that explained soaring flight by “so-called” rising currents which Pénaud “supposed” to exist in the atmosphere.

Like Mouillard, Hureau de Villeneuve found Pénaud’s interpretation unacceptable and he gave two reasons for his inability to agree with Pénaud. The first was that, if these thermals existed, all objects — not only birds — would go up, and the second was that if these rising currents really existed, birds would presumably be able to soar but would not be able to come down again when they wanted to.

Continuing his analysis of Mouillard’s book, Hureau de Villeneuve stated that a soaring bird was nothing but a kite in which the line was replaced by a “continuous displacement of the centre of gravity” which was the result of “a great instinctive skill on the part of those birds”.

These premises were nonsensical and, coming as they did from the president of the French aeronautical society, they may give us an inkling of why Pénaud at times had great difficulty in keeping an even temper when discussing aeronautics with his colleagues at the society meetings.

It is difficult to assess the real importance of Mouillard’s ideas. His book was very well received on publication, and he certainly inspired several pioneers who worked during the last decade of the nineteenth century. His influence extended to the United States just at the crucial moment when human flight was nearing its realization.

But in the light of our present knowledge, his influence, oriented as it was in 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 envisaged by Pénaud. At the rear there was a horizontal tail that could be moved up and down by the pilot, more for adjusting balance in flight than for control, and there was also a vertical rudder for steering to the left or right.

For the maintenance of equilibrium in flight, Goupil had envisaged an extraordinary mechanism which he called a régulateur. This consisted of two vanes placed on outriggers at some distance from the body to the left and to the right and which could be moved in opposition to each other in order to re-establish the lateral position of the aeroplane if this, for any cause, were to become upset by an involuntary rolling movement. These vanes thus served as ailerons that were similar to those described by Boulton in his patent of 1868 and one is tempted to look for some relation between one and the other but it is hardly likely that a French engineer in 1884 would have reviewed all the English patents of 15 years before.

Apart from their aileron effect, these vanes could also move in conjunction and served as elevons to act on the longitudinal position in flight. The régulateur was actuated by a heavy pendulum that worked in conjunction or in opposition and therefore served as a system for automatically maintaining balance during flight.

Goupil’s essay ended with the statement that flying machines would be cumbersome as well as difficult to shelter and to garage but that these difficulties would probably not stop the coming of the fixed-wing aeroplane, and he has proved to be right.

Lawrence Hargrave

Another important aeronautical event that took place in August of 1884 was the publication of the first of a long series of papers by Lawrence Hargrave, a keen and original researcher who lived in Australia. He had just started a study of aeronautics that would lead to several practical and important discoveries; it is interesting to note here that Hargrave and Goupil would both 21 years later be instrumental in saving the first French flying pioneers from continuing along a mistaken path resulting from serious errors of conception.

Hargrave was convinced that only international cooperation could lead to worthwhile results and he always resolutely refused to take out patents on any of his numerous discoveries. In a letter he later wrote to Chanute, he stated his beliefs as follows: “Workers must root out the idea that by keeping the results of their labours to themselves, a fortune will be assured to them ... The flying machine of the future like everything else ... must be evolved gradually. The first difficulty is to get a thing that will fly at all. When this is made, a full description should be published as an aid to others.” These were wise and true words which, had they been heeded, would have prevented many a personal tragedy among the hardworking searchers after the heavier-than-air machine and the internal combustion engine.

1883 to 1889: Advent of the Powerplant

Hitherto the progress towards the aeroplane had been mainly on the theoretical and ideal plane. Many projects and hypotheses had been disclosed and a few model aeroplanes had flown, but 1884 witnessed the great advance of the lighter-than-air ship when Commandant Charles Renard and A. C. Krebs’ dirigible “La France”, built with government funds by the official Aeronautical Institute at Chalais-Meudon, left its shed on 9 August, made a closed-circuit flight and returned to its base. This flight was followed by several more and the airship thereby entered the field of practical application and all eyes now turned towards lighter-than-air flight as possibly a better way of achieving human conquest of the air.

The advent of the successful airship in France was seen by many supporters of heavier-than-air flight as a calamity and the result was that between 1885 and 1889 nothing of importance was achieved in France in the field of aviation. But this ideal was never long out of the minds of the pioneers and during the next decade there were steps towards the definitive triumph, mainly because of the advent of the light internal combustion engine, even though during these five years it was the steam engine that claimed the greatest advances.

In 1883, Count de Dion, in collaboration with Georges Bouton and Charles Trépardoux, designed a light water-tube generator and engine which was used to power a light steam vehicle. Five years later the water-tube boiler, already proposed by Cayley in 1809, was taken to another level by Léon Serpollet who used extremely thin tubes, made possible by new techniques in tube-drawing. These thin tubes, when heated, caused the water they contained to evaporate instantly. It was the advent of the “flash steam generator” that made the very light steam engine possible and which very soon afterwards was used in full-size aeroplane experiments.

If between 1884 and 1889 nothing of importance was achieved in furthering human flight with machines heavier than air, the following decade, the last of the nineteenth century, saw an impressive blossoming of ideas that for the first time evolved into attempts to build and test full-sized man-carrying flying apparatuses.

Engines were now available that it was hoped would bring flight by mechanical means into the realm of the possible. There was also no shortage of soaring flight devotees and, because of the low power requirements and the possibilities of preliminary testing without an engine, these were the first to achieve free flight.

The Fin de Siècle

During the last decade of the nineteenth century a deadly earnestness of purpose set in as well as a willingness to assume great risks, which led to the first fatalities in the history of modern aviation. Even so, the particular characteristic of the 1890s was the fact that, in the case of two experiments with full-sized powered flying machines, the lucid teachings of Cayley and Pénaud were disregarded. They were forgotten, ignored or even rejected and the essence — once take-off became possible — was thought to lie in controlled flight, in maintaining balance by continuous intervention on the part of the pilot. The result was a great deal of confusion and a colossal waste of money and effort incommensurate with the results obtained.

When experiments with man-carrying gliders began, the need for inherent stability soon became apparent to the pioneers who followed this path. What Pénaud had proposed through study and inspiration was now rediscovered by trial and error, and by the end of the century it seemed, as Cayley had prophesied, that by applying a light engine of low power output to a glider, human flight was to become possible. But this also proved to be a wrong assumption.

1889 was the year in which the different ideas and ideals began to take shape. During that year the aviation movement, which had been active in Britain and France, extended to the whole industrialized world when Austria, Germany and the United States became involved, the latter taking on a pre-eminence that eventually led to the first powered flight on record.

Just as the year 1876 had seen the appearance of the Brayton engine, Otto’s four-stroke cycle and Pénaud’s master patent, as well as being the centennial year of US Independence and the accompanying Centennial International Exhibition of Philadelphia, 1889 was the centennial of the French Revolution. To commemorate that event an international exhibition was staged in Paris that was to surpass anything achieved hitherto.

The previous year an aeronautical show had been staged in Vienna and Wilhelm Kress, an Austrian enthusiast, had displayed a fine flying model with fixed monoplane wings as well as a fixed tail. Fitted with two counter-rotating propellers, each driven by twisted strands of rubber, it flew very well and looked like an improved Pénaud “Planophore” and that was what it amounted to. During the 1870s Kress had travelled to Paris and worked for a time with Pénaud himself and, like Pénaud, he thought that his successful flying model gave him the possibility of building a full-sized aeroplane. The next years were spent looking for support, which he eventually received in 1898, after ten years of increasingly frantic supplication.

There was a well-attended exhibition of all things relating to ballooning in Austria in 1888, but the big event was undoubtedly the great Paris Exhibition of 1889. Because of the great number of people who were expected to attend, an international aeronautical congress was arranged between 31 July and 3 August. A number of papers were to be read at the congress, including several dedicated to heavier-than-air flight.

Among the members who were enrolled at the 1889 Congress, were two American delegates. The first was Samuel Pierpont Langley. Born in 1834, Langley had just been appointed Assistant Secretary of the Smithsonian Institution in Washington, DC, and the following year he became its secretary.