Engineers, who was stationed in Sydney, provided him with details about Brotherhood’s radial torpedo engine. So in 1888, Hargrave built the first of thirty-six aero engines of different types which he was to manufacture during his aeronautical experiments. The first was a single-cylinder engine moved by compressed air.
Then, in 1889, Hargrave built a three-cylinder radial engine after the Brotherhood pattern but with the peculiarity that its crankshaft was fixed and the cylinders revolved around it. The cylinders were attached to the blades of a propeller and thus the first rotary aero engine came into being. It started Hargrave on the road to research into fixed-wing propeller-driven aircraft, as he had already become acquainted with previous experiments along those lines, and also with Pénaud’s writings, and probably with Cayley’s as well.
During 1889, ideas around internal combustion engine construction for airships or aircraft were running wild in France. It all started with Fernand Forest, who had published a drawing in 1888 of an air-cooled engine which had thirty-two cylinders arranged radially around a four-throw crankshaft. Designed for 120 hp, nothing tangible ever came of it except fame for Forest later on. And in 1889 Count de Dion applied for two patents for internal combustion engines, one was a three-cylinder rotary and the other a big ten-cylinder radial with many original features.4 This flurry of activity was to lead to the creation of the first real aviation engines about ten years later.
The important pioneers of the following decade had started with their specific activities by 1889. Many of them were still around with advice and counsel when the era of real flying began, but at the turn of the century the heavier-than-air flying machine had not yet found its definitive shape, nor was there a clear-cut solution in sight.
4. Automobile Quarterly Vol. 15, No. 8, pp. 286-289.
Clément Ader
Comparing the different attempts to fly full-sized machines during the 1890s, it appears that the results were inversely related to the sums of money spent on them. Two very expensive endeavours to develop a powered flying machine failed without showing any practical result nor leading to further development, or even influencing anybody.
The first flying machine ever to be built was that of Clément Ader, the “Eole”. It was being readied at the end of 1889 after years spent on design, experiments on a small scale, actual construction and preliminary tests.
The “Eole” was said to have a wing surface of about 300 sq ft, a total weight of 650 lbs and was powered by a steam engine developing 20 hp. If these figures are correct, the wing loading amounted to 2.4 lbs/sq ft and the power loading to 32.5 lbs/hp, which was sensational for that time.
Sir George Cayley had calculated that a winged machine loaded at 1 lb/sq ft would become airborne at a speed of 35 ft/sec. (about 25 mph). The higher wing loading of the “Eole” must have raised take-off speed to over 30 mph. “Eole” did not use any form of assisted take-off, but ran over level ground under its own power in the modern manner. But it is impossible to know whether an acceleration from zero to 30 mph was ever achieved.
Only patent drawings of the original “Eole” remain. It is a marvel of engineering which fills us with amazement. The tricks and devices used in order to obtain lightness from the materials employed — including bamboo, wood and steel tubes — verge on the incredible and it is a pity that so much ingenuity did not lead to more positive results. Modern attempts to recreate and evaluate the craft have met with mixed results. A full-size replica built in 1990 at the École Centrale Paris crashed on its first flight, injuring its pilot and leading to the termination of the experiment. Scale models, however, have been successfully flown.
Ader invested a small fortune in building the “Eole”. He is said to have spent the around $120,000 on his aeronautical activities up to 1891.
The first tests were made on the grounds of the property of Madame Isaac Péreire at Armainvilliers, near Paris. The Péreires were a family of bankers and Ader had been associated with them during his work in developing the telephone.
The “Eole” was brought to Armainvilliers in a special covered cart for secrecy. A strip of about 600 yards was prepared and a few tests were supposedly held during the autumn of 1890. But it is not certain whether these tests ever took place at that time and still less if they were successful. Ader himself later claimed to have become airborne over a short distance (50 metres or 165 ft) on 9 October 1890.
Nobody was present at that flight except Ader’s two closest assistants. Everybody living on the property had been asked to keep away, even, according to one source, the lady of the manor, which seems hardly credible.
For want of official witnesses, these were replaced by a few lumps of coal which were buried at the precise place of the alleged take-off by Ader’s assistants. The most amazing part of this story is that these lumps of coal were dug up 47 years later, which is remarkable in itself.
Ader himself did not reveal these flights until 1906 so that in 1890 the feat was a complete secret. But when more information was wanted later on about this undoubtedly important event, a gardener was found who, in spite of the interdiction, had hidden in a bush with some other men to observe the experiment. In 1908 this gardener claimed to have seen Ader in his “Eole” climb to 50 cm height (20 inches) and fly over a distance of 10 ft, which is a very short jump indeed. But no definite proof of that 1890 flight exists unless one is willing to accept the silent testimony of a few lumps of coal.
It would have been difficult to keep an event of such importance completely secret and something did filter through to the Paris press during the summer of 1891, which is probably the time when these tests were started, rather than in 1890. On 20 June L’Illustration mentioned secret trials and despatched a reporter who saw “an enormous bird of bluish hue” and who was also able to draw a sketch showing a flying mechanical bat on skids but this may have been a misinterpretation.
Ader himself gave interviews to several newspapers, notably to Le Temps of 9 July 1891, in which he did not mention any previous flights but told the story of his earlier studies that had led to the construction of “Eole”, which was supposed to be being tested around that time. He stated that “the problem was an exceedingly difficult one, involving enormous mechanical difficulties which increase rapidly with the size of the apparatus”. The “Eole” was described in La Revue de l’Aéronautique during 1893.
After the uproar in the press during the summer of 1891, Ader showed the “Eole” in a pavilion belonging to the city of Paris where it was inspected by the Minister of War, Charles de Freycinet; though it is strange that no photograph of the aeroplane was taken on that occasion.
De Freycinet was interested and Ader was allowed to move his aircraft to the military camp of Satory for further tests and for evaluation as to its possible military usefulness. Ader also claimed to have flown the “Eole” at the Satory camp, but very soon after its arrival in September 1891, it deviated from its course during one of the test runs and struck a pile of material that had served to prepare the test area and when the officer despatched to inspect Ader’s “Eole” arrived, he found nothing but a wreck.
Having spent much of his fortune on aeronautical experiments, Ader could have become dispirited but he seems to have possessed that indestructible faith in his own vision that marks so many outstanding personalities.
He was able to convince the officials of the War Ministry and on 3 February 1892 a contract was signed with the French State which accorded Ader a payment of 300,000 francs ($60,000) for the construction of a new aeroplane. He was also promised the return, by an act of Parliament, of the 600,000 Frs he had already spent, plus an additional sum of a million francs in return for the relinquishment by Ader and his heirs of all rights over his invention.
This contract sounds highly