Читать книгу The Rise of the Flying Machine - Hugo Byttebier - Страница 33

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 irrational because Ader bound himself by its terms to build an aeroplane able to carry a pilot and a passenger or the equivalent weight (75 kg) in explosives, as well as enough fuel and water for a flight of six hours at 34 mph with the ability to reach an altitude of 1,000 ft. These were daunting requirements for a man who had just built a machine that was barely able (if at all) to lift itself over a few feet with just the inventor on board. Ader must have been either a determined optimist or desperate for money.

Once the contract was signed, Ader started work on a second single-engined aeroplane but meanwhile he calculated that in order to comply with the clauses of the contract he would have to build a bigger aeroplane carrying two engines, each driving a propeller.

The authorities in charge agreed with his new proposals and in July 1894 an additional sum of 250,000 Frs ($50,000) was granted. These two large sums did not come from government funds but were part of a legacy made by Giffard to the French State, perhaps with the proviso that a part or the whole of the legacy was to be expended on the construction of an aerial machine.

It should be recalled here that Ader received the money that Pénaud had hoped to obtain for furthering his own experiments and when this hope was thwarted it led to Pénaud’s suicide, followed by that of Giffard.

The “Avion III”, as the new aeroplane was to be called, closely followed the pattern of the “Eole” in that it was another tailless bat-winged machine but it was bigger, having a wing surface of 430 sq ft at their maximum extension and when finished it weighed about 400 kg (880 lbs). Its two steam engines produced a total output of at least 40 hp (some sources claim 60 hp) so that, with a wing loading of 2 lbs/sq ft and a power loading of less than 20 lbs per hp it was a great advance over the already extraordinary specifications of the “Eole”, and Ader may well have believed that he would be able to comply with the clauses of the contract.

A big building lot was acquired and a complete aeronautical factory was built. Twenty-three men were engaged and work progressed during four years, the first time that so much money had been spent on an aeroplane.

The construction probably took more time than had originally been estimated but in 1897 the “Avion III” was ready to Ader’s satisfaction. The extremely light steam engines functioned and the wings were submitted to a static loading test corresponding to the weight of the machine. When Ader informed the War Ministry of the completion of the aeroplane a committee was appointed, consisting of three generals and three learned professors, all with excellent credentials and headed by General Mensier as president of the committee.

After inspection at the workshops, the “Avion” was moved to the manoeuvring grounds of Satory where, under the supervision of Lieuteneant Binet, a testing ground was prepared, consisting of a circular area 120 ft wide and with a diameter of 1,500 ft.

The expediency of selecting a circular testing ground may be questioned but Ader probably wanted to test his aeroplane on calm days and a ring form takes less space than a square or rectangular area.

A first test was held on the 12th October in the presence of General Mensier. Ader had to wait until sunset for the wind to drop and he started on his first trial run at 5.25 pm. With the machine running at around 12 mph, Ader, by means of a steerable rear wheel, was able to follow the chalk line which ran down the middle of the circular track and, having made a complete circuit, he stopped at his point of departure.

This was considered a success, so a trial flight was arranged for two days later, on 14 October. This time General Mensier was accompanied by General Grillion, another member of the Committee, with Lieutenant Binet, who had been in charge of the preparation of the testing ground, was also present. According to the official report drawn up on 21 October by General Mensier, there was a fairly strong and gusty wind blowing from the south.

It is to be wondered why Ader, after all the time and money spent on this project, did not insist on waiting for a calm day, as the report states that Ader had explained the danger of gusts of wind to the generals. Anyway, towards sunset the wind appeared to die down and it is possible that the generals did not want to postpone the trial for another day.

But the wind had not died down completely, and Ader, starting at 5.15 pm had the wind from the rear. When his machine had completed a quarter of the circular area and was running at a brisk pace, a gust of wind caught it from the side and the “Avion III” suddenly swerved away from the track, struck the ground with a wing and came to a stop, much damaged. On seeing his machine leave the track, Ader shut off the steam immediately, which was the best thing he could have done. In his official report General Mensier explicitly stated that at no point of its run did the “Avion” become airborne, although the rear wheel may have left the ground over a short distance. Lt Binet later confirmed this to the eminent engineer Armengaud, “he did not leave the ground or at the most lifted a few centimetres”.

The official report ended with the recommendation that the trials be continued the following spring, but nothing came of it and Ader’s aeronautical experiments were over. But, as sometimes happens, that event was to have a sequel that has had consequences up to the present day.

After Santos-Dumont made the first officially recorded flight in 1906, Ader came forward with the claim that on 14 October 1897 he had made a flight of 300 metres. On the basis of the sketch he presented, Ader would have taken off and flown with a ¾ rear wind. Ader, who had himself observed in 1882 that no bird ever takes off with a wind from the rear or from the side, should have known better than to make such an absurd claim, but sour grapes or the inability to continue enduring the great financial and moral loss he had suffered, made him do it. But because the making of a “first flight” acquired a bigger aura in the eyes of the general public than the construction of the first correctly designed aeroplane, Ader’s claim is still taken seriously and is considered an important historical milestone, which in a way it is.

Actually, had Ader been able to effect a take-off to the satisfaction of his military backers, his troubles would only just have begun. Ader’s aeroplane was deficient in design because as Victor Tatin, Pénaud’s disciple, later remarked: “Ader’s aeroplane could not fly because it was not stable.” This means that had Ader’s “Eoles” or “Avions” ever taken off they would have been incapable of a normal stable, and consequently safe, flight.

It is significant to note here that there exist a few sketches drawn by Ader showing an aeroplane with two propellers and a tail to the rear in Pénaud’s manner. When he decided upon a tailless machine it was Mouillard’s philosophy he adopted. Mouillard had stated in 1879 that the tail was of no use in a bird and when Ader took up his aeronautical experiments again in 1881 he did so under the inspiration of Mouillard’s ideas (his book had been published in 1881) and their impact on the French aeronautical community at that time.

Ader entrusted the balance of his aeroplanes to an unstable system of which the main factor was a complicated series of dispositions for moving the wings. The movements of which these wings were to be capable have been described as follows:

1) The wings could be moved forward or backward around a spindle.

2) The wings could vary their surface.

3) The wings could be warped individually.

4) The wings could vary their camber.

All this was to be effected by little handles and winches, and is reminiscent of d’Esterno’s propositions of 1864, but that this could ever have led to an aeroplane capable of a safely sustained flight is unthinkable today, so that any discussion about flight priorities in Ader’s case is of purely academic value.

What took on a special significance was the ability of Ader’s aeroplane to warp the wings, apart from the other movements of which they were supposed to be capable. In his patent Ader explained that “this operation is destined to warp (gauchir) the tip of the wing (which the French call ‘aileron’) in order to break or re-establish the equilibrium of the wings”.

The method for warping the wings described in Ader’s patent was to acquire a special importance about twenty years later when it helped to defeat an attempt to monopolize aviation by means of a patent claiming an exclusive priority on the warping of wings, including the use of ailerons.

Ader’s “Avion III” was never tested again, but it is still with us and is on exhibition in the Musée des Arts et Métiers in Paris.