About Clement Ader it is often said that on October 9, 1890, he flew a man carrying plane for a distance of about 50 meters.

After searching the archives the best evidence I found, in support of this assertion, is an article published on July 11, 1891, and signed Gaston Tissandier (French chemist, aeronaut and founder of La Nature). The author of the text says that after reading stories, in newspapers, about a machine built and flown by C. Ader, the inventor was interviewed and he proved to be quite secretive but finally, assaulted by insistent questions, Ader said his plane had risen to 50 cm to 1 meter, above the ground. The date of the trial is not specified and G. Tissandier does not appear to be convinced that Ader told the truth.

Question: Are there other articles or documents of the time that support the claim that on October 9, 1890 or at any date before 1897, Clement Ader flew a heavier-than air machine?

(As a remark: This is not a question about the experiments of Ader with his 1897 plane, financed by the French government.)

This is an approximate English translation (made by me) of the French article:

"Mr. Ader's mechanical bird. - About a fortnight ago, several of our most popular political journals announced that Mr. Ader, the scientist and pleasant electrical engineer, had built a marvelous aircraft which would bring to the field of science the much sought-after discovery of air navigation. It has been asserted that on a property at the outskirts of Paris, Mr. Ader rose with a mechanical bird having a powerful propulsor; and since then, the news has continued to travel in the world, somewhat amplified by the echoes. We wanted to know what was true in these stories, and we went to see Mr. Clément Ader, whose telephone and endless rails we once described.

To our regret, it was not possible for us to collect the precise information we would have liked. Mr. Ader told us that the description of the experiment, as presented by the newspapers, was grossly exaggerated, but the fact of building an aircraft was true. The ingenious physicist claims to have found a practical aviation device; he refuses to give a description of the engine that drives it, and he has no intention of subjecting it to further tests, for the time being. Mr. Clément Ader, as a result of our insistent questions, told us that he had actually carried out a decisive experiment. His mechanical bird, built after ten years of experiments and work, is shaped like a large bat with outstretched wings. The apparatus is constructed of hollow wood and silk; when the wings are opened, they span 16 meters. The animal's body is hollow and houses the aviator and the engine. This very light and very powerful motor operates a propeller which make the aircraft move. The wings do not flap and remain opened. When the propeller begins to work, the mechanical bird, mounted on wheels or skates, runs on level ground, with a fairly high speed, then little by little it finds its fulcrum in the air, and it manages to rise from the ground and continue its ascent. This is what Mr. Ader told us. - But, we asked, how high could the device rise? - Here Mr. Ader does not give precise information; as we insisted however, the inventor told us that he had risen to a low height, and, to give us an idea of ​​the elevation, he rose his hand at 50 centimetres or 1 meter above the ground. - Does the device operate for a significant period of time? - M. Ader replied that the time was short, but that he intended to build an apparatus which would rise higher and would function for a longer period. The inventor intends to mount his mechanical bird and show it, not to the public, but to scientists and friends; he added that he would show it in an inert state, that he had no plans to make it work, that he had spent considerable sums on his studies and that he needed capital to continue and develop its constructions.

Mr. Ader is too good a physicist not to know that in the field of experimental science, demonstrations must be made by experiment; both scientists and capitalists will all ask him for it, and whatever good opinion we may have of the inventor's merit, it is only after the experiment, when it is presented to us, that we draw our conclusions.

G. T."

The French original

Gaston Tissandier, "L'oiseau mécanique de M. Ader.", Supplément à « La Nature » du 11 juillet 1891 (n° 945), Publié sous la direction de M. Gaston Tissandier, p. 6.

L'oiseau mécanique de M. Ader. — Il y a une quinzaine de jours, plusieurs de nos journaux politiques les plus répandus ont annoncé que M. Ader, le savant et sympathique ingénieur-électricien, avait construit un merveilleux appareil d'aviation qui allait apporter dans le domaine de la science la découverte tant cherchée de la navigation aérienne. On a affirmé que l'on avait vu, dans une propriété des environs de Paris, M. Ader s'élever dans un oiseau mécanique, muni d'un puissant propulseur; et depuis, la nouvelle continue de courir le monde, quelque peu amplifiée par les échos. Nous avons voulu savoir ce qu'il y avait de vrai dans ces récits, et nous avons été voir M. Clément Ader, dont nous avons jadis décrit le téléphone et les rails sans fin.

A notre regret, il ne nous a pas été possible de recueillir les renseignements précis que nous aurions désiré. M. Ader nous a affirmé que le récit de l'expérience annoncée par les journaux était fort exagéré, mais que le fait de la construction d’une appareil d'aviation était vrai. L'ingénieux physicien affirme avoir trouvé un appareil d'aviation pratique; il se refuse à donner la description du moteur qui l'anime, et il n'a pas l'intention de le soumettre à de nouveaux essais, quant à présent. M. Clément Ader, sur nos interrogations pressantes, nous a dit qu’il avait fait, en réalité une expérience décisive. Son oiseau mécanique, construit à la suite de dix années d'expériences et de travaux, a la forme d'une grande chauve-souris aux ailes étendues. L'appareil est construit en bois creux et en soie; quand les ailes sont étendues, elles ont 16 mètres d'envergure. Le corps de l’animal est creux et abrite l'aviateur avec le moteur. Ce moteur, très léger et très puissant, fait agir une hélice qui imprime le mouvement à l’appareil. Les ailes ne battent pas et restent étendues. Quand l’hélice commence à fonctionner, l'oiseau mécanique, monté sur des roues ou des patins, court sur un terrain uni, avec une assez grande vitesse, puis peu à peu il trouve son point d'appui dans l’air, et il arrive à se soulever du sol et à continuer son ascension. Voilà ce que nous a raconté M. Ader. — Mais, avons-nous demandé, à quelle hauteur l'appareil peut-il s'élever? — Ici M. Ader ne donne pas de renseignements précis; comme nous insistions cependant, l'inventeur nous a dit qu'il s'élevait à une faible hauteur, et, pour nous donner une idée de l'élévation, il étendait sa main à 50 centimètres ou 1 mètre au-dessus du sol. — L'appareil fonctionne-t-il pendant un temps d’une durée appréciable? — M. Ader nous a répondu que ce temps était court, mais qu'il se proposait de confectionner un appareil qui s'élèverait plus haut et fonctionnerait pendant une durée plus considérable. L'inventeur se propose de monter son oiseau mécanique et de le faire voir, non pas au public, mais à des hommes de science et à des amis; il a ajouté qu'il le montrerait à l'état inerte, qu’il n'avait pas le projet de le faire fonctionner, qu'il avait dépensé des sommes considérables pour ses études et qu'il lui fallait des capitaux pour continuer et développer ses constructions.

M. Ader est trop bon physicien pour ne pas savoir que, dans le domaine de la science expérimentale, les démonstrations doivent se faire par l’expérience; les hommes de science comme les capitalistes la lui demanderont tous, et quelque bonne opinion que nous puissions avoir du mérite de l'inventeur, c’est de l'expérience seule, quand il nous sera donné de la voir, que nous tirerons notre jugement. G. T.

  • 5
    $\begingroup$ This is not an answer as I have no definitive information, but in general when an inventor refuses to demonstrate or give evidence on progress it means there's nothing to show. $\endgroup$ – GdD May 3 at 8:13

The behavior of Clement Ader's 1897 plane represents strong evidence against any flight performed by the same inventor in 1890 and 1891 using similar machines.

The Oct. 21, 1897 report, made by general Mensier, and its annex of Oct. 27 do not leave room for interpretation. The 1897 airplane never left the ground with its front wheels during the Oct. 12 and 14 officially witnessed trials, but the rear wheel rose into the air.

Ader's Avion III is a fundamentally flawed design. A model tested in 1990 (see the video below) behaved identically. The rear wheel leaves the runway but finally the apparatus leans forward too much and hits the ground with its propellers. The model, like the original, also has the tendency to veer to one side. In the case of the 1897 plane, once the rear wheel no longer touched the runway, the only means that remained for steering the plane was the vertical rudder which (probably) was inefficient at low speeds.

Had C. Ader flown in 1890 and 1891 he would have built in 1897 a machine at least as good as the previous two apparatuses.

Model of Ader 1897 plane, tested in 1990, which behaved multiple times in a similar way as the real airplane.

Model of Ader 1897 plane, tested in 1990, which behaved multiple times in a similar way as the real airplane.

  • $\begingroup$ Just because I'm upvoting, doesn't mean I believe that this is the absolutely correct answer, but there is some useful research effort here-- $\endgroup$ – quiet flyer May 5 at 3:07

The ancestor of airplanes was Éole. ("L’Aïeul des Avions fut l’Éole." - Clement Ader)

In December 1906, when it was already demonstrated in front of official witnesses, that the man carrying planes can take off and fly, Clement Ader wrote a book, published in 1907, in which he established himself as the father of aviation. He claims flights for all his three planes of 1890, 1891 and 1897 but for the first two machines the inventor does not bring forward any evidence (old letters, articles, declarations of witnesses, etc.) in support of his pretentions.

Here is an electronic translation (brushed a bit by me) of the first part of Ader's 1907 book:

The first stage of the military aviation in France

Paris, December 1906.

The text that follows does not pretend to be a history of Aviation. Others, better documented, will write it one day and it will not fail to be quite interesting. We will present here only a particular fact belonging to the Military Aviation, and we will report it exactly as it happened.

The name Avion [airplane], used to designate the flying machines intended for War, comes, like that of Aviation, from the Latin word Avis which means bird.

The ancestor of Airplanes was Éole. Being dominated by this firmly established idea, that aviation should be used above all for National Defense, we always conducted our work, since 1882, in the greatest secrecy. Following extensive research on the flight of birds, on Aerodynamics and special mechanics for Air Navigation, Éole was built in a laboratory located on Pajou street in Passy. It consisted of two wings similar to those of bats; they could be folded. The motive power was provided by steam and it turned a propeller placed in front of the plane. Two non-steerable wheels carried the aircraft and a third, at the rear, steered it on the ground. A rudder was used for steering the apparatus in the air. After being completed, it was necessary to choose, for trying the plane, a discreet and quiet place. We found it in the Parc d’Armainvilliers, belonging to Mrs. Isaac Pereire, and it was made available to us by her son, Mr. Gustave Pereire.

A straight line runway was built, the grass was removed, the soil compacted and leveled by a roller, so as to make visible and record the traces left by the wheels, from the smallest decrease in the pressure exerted by the wheels on the ground to complete lift-offs. During one of these experiments, on October 9, 1890, over a distance of about 50 meters, Éole lost contact with the ground for the first time, using only its motive force. This small event was not recorded in a written report, but our foremen buried blocks of coal in the ground at the exact spot where we took-off in our aircraft. What is certain is that these witnesses are still on the surface of the ground [alive] and that it would be possible to find them if this thing became necessary. The experiments did not continue due to a major damage the steam generator suffered.

At the time, Eole was considered, by informed people and by the Scientific Press, as the first aerial device, mounted by a man, having flown at a low height and over a short distance.

The following year, in 1891, the generator of Eole was rebuilt and improved. The experiments were repeated in September, on a larger field, with the authorization of the Minister of War, at Camp de Satory. The area [the runway] was still straight like the first, but much longer, about 800 meters, - previously leveled and compacted. Longitudinally, in the middle of the runway, there was a white stripe, 1-meter wide, for guiding the aviator who was still ourselves. Several tests were made, flying here and there [hoping] and during one of these experiments Éole left the runway to the left for a length of about 100 meters, without leaving any marks on the ground. It remained at a low height, but completely supported by its wings. This deviation to the left, while flying, was caused by the central single propulsor as soon as the plane left the ground, an effect which we will explain later. Unfortunately, the machine came up violently against an ensemble of carts, buckets, etc. ... which had been used to trace, with lime, the central line. The apparatus was damaged to the point of not being able to continue the tests. The strong shaking we felt made us think about the drawbacks of a single central traction.

However, the results of these tests spread discreetly inside a small group of officers, and so we had the honor to be visited by Major General Mensier, then Director of the 4th Directorate (engineering) at the Ministry of War. Due to his kindness we had already owed the ministerial authorization which had enabled us to operate on a military terrain. We could only show him an Éole damaged and immobilized in its shelter.

A few days later, the damage to the aircraft was provisionally repaired; Mr. Berger, former Commissioner General of the Universal Exhibition, currently deputy of the Seine, who was very interested in our invention, had obtained for us from the Prefect of Seine the authorization to exhibit the machine in the Pavilion of the City of Paris, located at that time next to the Palais de l’Industrie. With some friends we had planned to present it to the world of scientists, of Finance and to the Press, having the intention of establishing a Research Society for continuing the aviation experiments. The airplane was about to be shown when M. de Freycinet, who was then President of the Council and Minister of War, expressed his desire to see it. He came, on Saturday, October 17, 1891, accompanied by General Mensier. Once his examination was completed, he took a decision: “This, he said, is an “Aerial Scout and Torpedo Craft” and the tests must be continued by the War Department for the National Defense. This is how the Military Aviation was born that day through the will of M. de Freycinet. This made us happy as long as we held the same beliefs.

We immediately made a general plan, and we were justified to do so, this was not a bold decision, by the numerous preliminary studies carried out from 1882 to 1891, as well as by the results obtained with Éole. Here are the main points: - Foundation of a school for Aviation and an Aviation Industry. - Establishment of a Military Workshop for building airplanes. - Air strategy and tactics. - Creation of an Air Force.

To fulfill this program, no doubt, resources were needed proportional to its importance; but could these expenses and the great projected benefits for the National Defense be really put in balance?

So, trusting the words of M. de Freycinet and in support of General Mensier, we started the work, without even waiting for written agreements establishing the conditions under which the work had to be carried out. This thing we did later.

The old laboratory-workshop on Pajou street which produced Éole became insufficient. It was necessary to build another, larger and more complete. This construction work took place in 1892, Jasmin street, 11 and 13, in Auteuil. It consisted of a mechanical workshop; another for modeling, the frames and canvas; several other rooms for the forge, stores, design workshop, office, study; a high roof room, 20 meters long by 10 wide, for tests, plots and assembling aircraft frames. In the courtyard and other related places, there were several more small buildings, sheds and the guard’s hut. The motive power was provided by a steam engine which powered many tools. The heating was done by heaters and by steam. We had to build a true factory, and this was necessary because of the complex activity that we had to carry out.

The establishment was placed under the rigorous jurisdiction of military laws and became, in fact, the first school of the Aviation Industry. An uninterrupted work was conducted in the most absolute secrecy. There, many inventions concerning Aviation, and a lot of manufacturing processes, were born, known only to our staff, and which constituted the nascent Aircraft Industry. ...

The book continues with the activity of Ader related to the construction and testing of his 1897 plane which, as I understand, is not a subject of interest for the current question.

The original text in French as written by Clement Ader in December 1906:

1907, Ader, Clément, "La première étape de l'aviation militaire en France", Paris, J. Bosc et Cie.

La première étape de l’aviation militaire en France

Paris, Décembre 1906.

Ce qui va suivre n’a pas la prétention d’être une histoire de l’Aviation, d’autres que nous, mieux documentés, l’écriront un jour et elle ne manquera pas d’être très intéressante ; il ne s’agira ici que d’un fait particulier qui appartient à l’Aviation Militaire, et nous allons le raconter fidèlement tel qu’il s’est accompli.

La dénomination d’Avion pour désigner les appareils volants destinés à la Guerre, dérive, ainsi que celle d’Aviation, du mot latin Avis qui signifie oiseau.

L’Aïeul des Avions fut l’Éole. Étant pénétré de cette idée, bien arrêtée, que l’aviation devait surtout servir à la Défense Nationale, nous avions toujours conduit nos travaux, depuis 1882, dans le plus grand secret. A la suite de longues recherches sur le vol des oiseaux, sur l’Aérodynamique et la mécanique spéciale à la Navigation Aérienne, l’Éole fut construit dans un laboratoire situé rue Pajou à Passy. Il se composait de deux ailes semblables à celles des chauves-souris ; elles se repliaient. La force motrice était fournie par la vapeur et faisait mouvoir une hélice placée à l’avant. Deux roues droites portaient l’appareil et une troisième à l’arrière le dirigeait à terre. Un gouvernail servait à la direction aérienne. Après son achèvement, il fallut choisir, pour l’essayer, un endroit discret et tranquille ; nous le trouvâmes dans le Parc d’Armainvilliers, appartenant à Mme Isaac Pereire et qui fut mis à notre disposition par son fils, M. Gustave Pereire.

Une aire fut tracée en ligne droite, le terrain dégazonné, battu et égalisé par un rouleau, de manière à voir et à enregistrer les traces des roues depuis les plus petits allègements jusqu’aux soulèvements complets. A l’une de ces expériences, le 9 Octobre 1890, sur une distance d’environ 50 mètres, l’Éole perdit terre pour la première fois, avec la seule ressource de sa force motrice. Ce petit événement ne fut constaté par aucun procès-verbal, mais nos contremaîtres enfouirent en terre des blocs de charbon à l’endroit précis où nous nous étions élevé dans notre appareil. Ce qu’il y a de certain, c’est que ces témoins sont encore dans le sol et qu’il serait possible de les y retrouver si cela devenait nécessaire. Les expériences ne continuèrent pas par suite d’une grosse avarie survenue au générateur de vapeur.

A cette époque, l’Eole fut considéré, par les initiés et par la Presse scientifique, comme le premier appareil aérien monté par un homme, ayant volé à une faible hauteur et sur une petite distance.

L’année après, en 1891, le générateur de l’Éole était refait et perfectionné, les expériences furent reprises au mois de Septembre, sur un terrain plus vaste, avec l’autorisation du Ministre de la Guerre, au Camp de Satory. L’aire était encore droite comme la première, mais bien plus longue, 800 mètres environ, - préalablement nivelée et battue. Il y avait longitudinalement, au milieu, une raie blanche de 1 mètre de largeur pour orienter l’aviateur qui était encore nous-mêmes. Plusieurs essais furent faits en voletant et à l’une de ces expériences L’Éole sortit de la piste à gauche sur une longueur d’environ 100 mètres, sans laisser de traces sur le sol, il était à une faible hauteur, mais complètement soutenu par ses ailes. Cette déviation à gauche, en volant, fut causée par le propulseur unique central dès que l’Avion fut libre en perdant terre, effet que nous expliquerons plus tard. Malheureusement, il vint buter violemment contre un matériel de chariots, de baquets, etc... qui avaient servi tracer, à la chaux, la raie centrale ; l’appareil s’avaria au point de ne plus pouvoir continuer les essais. La forte secousse que nous ressentîmes nous fit réfléchir sur les inconvénients d’une traction unique centrale.

Cependant, les résultats de ces essais s’ébruitèrent discrètement dans un petit cercle d’officiers, ce qui nous procura l’honneur de la visite de M. le Général de Division Mensier, alors Directeur de la 4° Direction (génie) au Ministère de la Guerre, à l’obligeance duquel nous devions déjà l’autorisation ministérielle qui nous avait permis d’opérer en terrain militaire. Nous ne pûmes que lui montrer L’Éole avarié et immobilisé dans sa baraque-abri.

Quelques jours après, les avaries de l’appareil étaient provisoirement réparées ; M. Berger, ancien Commissaire Général de l’Exposition Universelle, actuellement député de la Seine, qui s’intéressait beaucoup à notre invention, avait obtenu pour nous du Préfet de la Seine l’autorisation de l’exposer dans le Pavillon de la Ville de Paris, situé à cette époque à coté du Palais de l’Industrie ; avec quelques amis nous avions fait le projet de le présenter au monde savant, de la Presse et de la Finance, en vue de la formation d’une Société d’Études pour la continuation des expériences d’aviation. On allait montrer l’Avion, lorsque M. de Freycinet, qui était alors Président du Conseil et Ministre de la Guerre, témoigna le désir de le voir le premier. Il vint, en effet, le samedi 17 Octobre 1891, accompagné du Général Mensier. Son examen terminé, sa résolution fut bientôt prise : « Ceci, dit-il, est un « Éclaireur » et un « Torpilleur» Aérien et il faut faire continuer les essais par le Département de la Guerre pour la Défense Nationale. » C’est ainsi que naquit ce jour-là l’Aviation Militaire par la volonté de M. de Freycinet. Cela nous combla de joie puisque nous-mêmes étions animé des mêmes sentiments.

Nous fîmes immédiatement un projet général, et nous y étions autorisé, sans témérité aucune, par les nombreuses études préliminaires faites de 1882 à 1891, ainsi que par les résultats obtenus avec l’Éole. En voici les branches principales : — Fondation d’une école d’Aviation et d’Avionnerie. — Établissement d’un Arsenal pour la construction des Avions. — Stratégie et tactique Aérienne. — Création d’une armée Aérienne Aviatrice.

Pour satisfaire ce programme, sans doute, il fallait des ressources en rapport avec son importance ; mais que pouvaient être ces sacrifices en argent à côté des services qu’il était appelé à rendre à la Défense Nationale ?

Donc, confiant dans la parole de M. de Freycinet et dans l’appui de M. le Général Mensier, nous nous mîmes résolument à l’oeuvre, sans même attendre d’avoir arrêté par des conventions écrites, sous quel régime devaient s’exécuter les travaux ; ce que nous fîmes, d’ailleurs, quelque temps après.

L’ancien laboratoire-atelier de la rue Pajou qui produisit l’Éole, devenait insuffisant, il fallut en construire un autre plus vaste et plus complet ; cela eut lieu en 1892, rue Jasmin, 11 et 13, à Auteuil ; il se composa : d’un atelier pour la mécanique ; d’un autre pour le modelage, les charpentes et la voilure ; de plusieurs autres pièces pour la forge, les magasins, atelier de dessin, bureau, cabinet de travail ; d’une salle haute de toiture, de 20 mètres de long sur 10 de large, pour essais, tracés et montage des charpentes des Avions. Dans la cour et les dépendances il y avait encore plusieurs petits bâtiments, des hangars et la loge du concierge. La force motrice était fournie par une machine à vapeur qui faisait mouvoir de nombreux outils. On obtenait le chauffage par des calorifères et par la vapeur. Nous avions été amené à construire une véritable usine, et il le fallait bien à cause des multiples travaux que nous avions à exécuter.

L’établissement fut placé, rigoureusement, sous la juridiction des lois militaires et devint, de fait, la première École d’Avionnerie. Ce fut alors un travail ininterrompu dans le secret le plus absolu : là virent le jour quantité d’inventions concernant l’Aviation et une foule de procédés de fabrication, connus seulement par notre personnel et qui constituaient l’industrie naissante de l’Avionnerie. …


It is generally accepted by aviation historians that during a test at 9 October 1890 the wheels of Ader's machine briefly left the ground just barely and came back down 50 meters away. Later claims which Ader made in a book Military Aviation (Ader, Clément, "La première étape de l'aviation militaire en France", Paris, J. Bosc et Cie, 1907) published in 1909 are treated with more skepticism.

His claim of a 50-meter "powered hop" is plausible based on the size and weight of his machine and the engine power on board. He made the claim immediately after the event and there was at least one witness. On this basis he is given credit for building the first heavier than air machine which was able to rise from the ground unassisted. He has not received and did not claim credit for building a working airplane.

According to Sobolyev (История самолетов мира, 2001, p. 31) there is a document prepared by one of Ader's assistants in which he states:

Avion number 1, bearing the name "Eole" and under the control of Mr. Ader its inventor broke away from the earth and maintained itself in the air on its wings shaving the surface of the earth for a distance of approximately 50 meters with the help of but a single source: its own thrusting power. The test surface had been tamped with a roller and had a length of 200 meters and a width of 25 meters.

Sobolyev also cites a personal letter from Ader to Nadar dated 12 October 1890 (three days after the experiment). In it he says:

I have finally solved the problem after wearying labor and considerable monetary expense. My finished machine is called "Eole"; it has just now performed its first takeoff with me on board over a distance of 50 meters; this distance could not have been greater because the test surface was too small.

Both quotes above are my translations of Sobolyev's translations into Russian. I do not know whether Ader's letter translated from an English translation for directly from the French.

Sobolyev does not claim to have seen either document. For the statement by the assistant he cites Dollfus C., Bauche H. Histoire de l'aernoautics. Paris, 1932, p. 140. For the letter to Nadar he cites Gibbs-Smith C. Clement Ader. His flight-claims and his place in history. London, 1968. p. 9. Sobolyev says that the letter is in the National Library in Paris.

The claims which Ader made in 1917 are only slightly greater than what he made to Nadar in 1890. He claims to have made more hops which went a bit further and one big hop when a strong gust of wind hit the machine while it was in the air. If there is enough interest, I can add details later.

  • $\begingroup$ In an answer, I will translate for you and others, the first part of the work: "Ader, Clément, "La première étape de l'aviation militaire en France", Paris, J. Bosc et Cie, 1907". In his book Ader does not support with documents his claimed flights of 1890 and 1891. He bluntly declared himself the father of aviation. $\endgroup$ – duofilm May 4 at 8:13
  • $\begingroup$ @duofilm There is a 2003 English translation of Ader's book from Air University Press. The US Department of Defense has a scan of it on one of their websites. media.defense.gov/2018/Jan/04/2001862907/-1/-1/0/… $\endgroup$ – David42 May 4 at 13:42
  • $\begingroup$ The translation you mentioned is of another book by Ader as long as the inventor says at one point, see page 10, : "Now, writing these lines in October 1908". The book, that I translated in part, was published in 1907. $\endgroup$ – duofilm May 4 at 18:19

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