A.Weyl Fokker: The Creative Years (Putnam)
UNWILLINGLY TO SCHOOL
Among the other would-be pilots whose hopes were shattered by Buechner’s crash was Franz von Daum, an ex-officer of the German army, about fifty years of age and of independent means. He was so keenly interested in aviation that he was willing to help finance the construction of an aeroplane. This was Fokker’s opportunity, and he and von Daum entered into an informal partnership: Fokker would construct an aeroplane to their ideas; von Daum would put up most of the money and provide the engine; both would learn to fly on the completed aircraft. Such seems to have been the general nature of their agreement. Von Daum apparently gave up his interest in aviation after the abrupt ending of his collaboration with Fokker; we therefore have only Fokker’s account of the whole affair, and this, of course, is somewhat one-sided.
Von Daum provided a 50-h.p. Argus aero-engine, Fokker 1,500 marks of his father’s money and his services as an aircraft constructor. Fokker implies that he designed the aircraft as well: this is doubtful, and probably only partly true. There are grounds for believing that von Daum had ideas of his own, and that the engineers of the Automobil-Fachschule, and perhaps Jacob Goedecker too, contributed constructive advice and design ideas.
Study of the contemporary aviation journals provides support for the belief that the design of the Fokker-von Daum monoplane was not entirely Fokker’s. Published reports described this monoplane as an aeroplane of the Automobil-Fachschule, Mainz. An illustration depicted the aircraft standing between two biplanes of the Automobil-Fachschule, and the caption stated that all three were the training aeroplanes of the Fachschule. Fokker could be seen in the pilot’s seat of the monoplane but his name was not mentioned, either in the caption or in the accompanying notes. This seems to leave little doubt that the Fachschule had contributed substantially to the aircraft. If such descriptions had been inaccurate Fokker, and probably his partner too, would certainly have protested to the publishers concerned, the more so because Fokker had demanded the return of his 500-mark deposit from the Fachschule and must have regarded his personal connexion with its aviation course as severed.
However, there is little doubt that the general arrangement of the aircraft came from Fokker, for it was similar in general configuration to his paper models. It was a tractor monoplane with pronounced dihedral on the mainplanes; the centre of gravity was fairly high above the wing. A small tailplane lay immediately behind the mainplane, but there was neither elevator nor rudder. Control was to be maintained by warping the mainplanes, differentially for lateral and directional control, and in the same sense for control in the looping plane.Construction of the machine began in the autumn of 1910; the work seems to have been done in the Wiesbaden workshop of the Automobil-Fachschule. In his autobiography Fokker states that the steel-tube frames of the mainplanes were made from rough drawings by “a Frankfurt company” ; the wooden components were made in “a neighbouring carpenter’s shop”. Fittings and other metal parts were produced in the Mainz workshops of the Fachschule. There is also the evidence of Jacob Goedecker’s testimony that his workshop contributed, but it seems that the extent and nature of that contribution will never be known.
The “fuselage” consisted of two parallel wooden beams; this idea obviously came from Goedecker, for the contemporary Goedecker monoplanes had the same feature. The influence of Goedecker could also be seen in such details as the tailplane design, seat mounting and engine installation.
For one who had such a high opinion of himself, Fokker was remarkably vague about the part he himself played in the making of this first aircraft. A possible explanation for this vagueness might be that, thanks to his lack of the theoretical knowledge that he so ostentatiously despised, he was incapable of any structural design work.
The Fokker-von Daum monoplane was completed by October 1910. The date is determined by the fact that a photograph of the aircraft in its original form, taken on the Wiesbaden-Dotzheim parade ground, was published in Flugsport for November 2, 1910. The partners seem to have contrived to remove their “training” monoplane from its attachment to the Automobil-Fachschule: before the end of 1910 it was at the airship ground of Baden-Oos, where its testing continued.
Like all experimental aeroplanes of that period, the monoplane was repeatedly modified as its trials proceeded. An essential addition was a conventional rudder: without it the aircraft was virtually uncontrollable on the ground, for no other provision for steering had been made. It was found that warping both wings in the same sense was totally ineffective as a means of control in pitch, consequently the trailing edge of the tailplane had to be made flexible (as on the Goedecker monoplane) to serve as an elevator. This proved effective, but the aircraft’s response when taxied at higher speeds indicated a disconcerting degree of instability. Stability was at that time regarded as perhaps the most desirable attribute an aeroplane could have; that it could be obtained by giving the wings pronounced sweep-back had been conclusively demonstrated in England by J. W. Dunne. Details and drawings of the successful Dunne biplane had appeared in Flugsport for July 6, 1910, and cannot have escaped Fokker’s notice. The Fokker-von Daum monoplane therefore acquired an appreciable degree of sweep-back.
Fokker himself did all the testing of the aircraft; indeed, he virtually prevented von Daum from trying to fly it. Selfish though this action was, it is perhaps well that it was so: Fokker was twenty, slim, wiry and agile, and had exceptionally quick reactions. Although he had no more flying 13 experience than von Daum he was, by virtue of being thirty years younger, more likely to achieve early success in flying their aeroplane, with its new and untried features.
Real success was not achieved until December 1910 when, after all the modifications described above had been made, Fokker succeeded in making a hop of about 100 yards in the monoplane. His labours had been crowned with success, and he was naturally elated and greatly pleased with himself.
As was his wont when immersed in developmental work Fokker had not spared himself. He never indulged himself with personal luxuries; he was a lifelong abstainer from alcohol, and he did not smoke; his sole weakness was sugar in every form. In his endeavours to get the Fokker- von Daum monoplane into the air Fokker had worked long and strenuously in the open. He contracted a severe chill, and went home to spend Christmas at Haarlem, to rest and recuperate.
Not unnaturally, Franz von Daum had come to resent the way in which his younger partner monopolized their jointly-owned aeroplane. Fokker’s absence gave von Daum his first opportunity to try his skill on the aircraft. Unfortunately he taxied into a tree and damaged the machine extensively. Von Daum was honest enough to tell his partner of the mishap at once, and a furious Fokker hurried back from Haarlem - once again his personal flying ambitions had been thwarted by what he regarded as the ineptitude of another.
The monoplane was so extensively damaged that there was little point in trying to repair it. In any case, Fokker had come to realize that it had been too heavy, complicated and unpractical; its destruction brought an opportunity to produce an improved aircraft. This idea Fokker put to von Daum who, chastened by his experience with the original machine, readily agreed. Fokker suggested that this time Jacob Goedecker should build the new monoplane to their ideas. Goedecker was also to help with the detail design.
Goedecker’s name has already been mentioned. He was one of the few qualified engineers who took an early interest in German aviation. He had devoted five years of university study to engineering and naval architecture and had done post-graduate research in the laboratory of Professor Junkers at Aachen University. His scientific work had been of a high standard. Goedecker’s interest in flying started in 1902 with the study of the infant science of aerodynamics. Thence he progressed to practical experiments, and in 1909 he constructed his first monoplane at Gonsenheim, near Mainz.
Fokker had made friends with this approachable, frank and helpful Rhinelander who had neither ambition to become a pilot nor the business acumen to make money out of aviation.
The first Goedecker monoplane had a cantilever wing that could be swivelled about a vertical axis for steering. Fokker and von Daum knew this aircraft well; several of its features influenced their ideas. It proved 14 itself capable of making short hops but was not conspicuously successful; it was therefore abandoned.
Early in 1910 Goedecker designed a Taube-like monoplane powered by a 50-h.p. Argus engine. Taube was the name of a very stable monoplane developed by Etrich and Wels with the guidance of Professor Ahlborn. The Taube wing was shaped like the seed leaf of Zanonia Macrocarpa, which gave perfectly stable glides; and the Etrich-Wels monoplane was remarkably stable. The name Taube was quite widely applied to other aircraft having a wing generally similar to that of the original Etrich-Wels machine.
On April 24, 1910, the Goedecker Taube made a complete circuit of the Grosser Sand parade ground near Gonsenheim. It was flying while Fokker was working on the clumsy pusher biplane of the Automobil-Fachschule; it was, in fact, the first aeroplane he saw flying.
Later in 1910 Goedecker built an improved model of his Taube; it incorporated more steel-tube construction than its predecessors, and probably gave Fokker and von Daum the idea of using steel tubing in their aircraft. Instead of exploiting his talent as an aircraft designer, Goedecker was content to remain in the comparative obscurity of Mainz, where, during 1911, he built three more Taube-type monoplanes and opened a flying school.
Fokker had much to thank Goedecker for. From him he learned more about technical matters than from anyone else during his long career in aviation. If Fokker had had a real grounding in engineering he might have learned enough from the modest Rhinelander to become an aircraft designer himself. Instead he was compelled throughout his career to depend upon the engineering abilities of others to design the aeroplanes that he falsely claimed to be his brain-children.
Goedecker was willing to build the new Fokker-von Daum monoplane. He agreed to design its structure and have the components made in his workshop; Fokker would work on the assembly of the machine.
In the new aircraft the ineffective and complicated wing-warping control was abandoned, and conventional elevator and rudder surfaces were fitted. Although Fokker might have found that models with swept-back wings and marked dihedral needed no lateral control, Goedecker knew that even the stable Zanonia plan-form could not do without it. The monoplane therefore had ailerons. The undercarriage, which differed from the type Goedecker had favoured up to that time, was a simpler, cleaner structure than that of the first monoplane. Power was provided by von Daum’s same 50-h.p. Argus engine, which had apparently survived the crash of the earlier machine.
The new monoplane was kept at the Dotzheim parade ground. It was a great improvement over its predecessor: it was lighter and its controls were effective.
Fokker, more than ever resolved to keep his partner from flying this precious monoplane, made progressively longer flights. As his experience increased so did his great natural talent for flying develop. On May 5, 1911, he succeeded in making a shallow turn at a height of about fifty feet. With this proof that “his” monoplane could fly and be controlled in flight, Fokker took and passed the tests for the pilot’s certificate on May 16. He was granted German Licence No. 88, issued on June 7, 1911, by the Deutsche Luftfahrer-Verband. Fokker had achieved his aim.
But if Fokker had attained his goal, von Daum had not; and he insisted that he would now learn to fly on the monoplane. Fokker’s counterarguments were unavailing. Although von Daum made quite a good start, he crashed and damaged the aeroplane beyond repair. He was unhurt physically, but the blistering tirade that the unfeeling Fokker delivered against him killed his enthusiasm for flying. He sold his share in the aircraft to Fokker - which was exactly what the shrewd Dutchman wanted.
J.Herris Fokker Aircraft of WWI. Vol.1: Spinne - M.10 & Watercraft (A Centennial Perspective on Great War Airplanes 51)
After Bruno Buechner, Fokker's associate, destroyed the first airplane Fokker had helped build, Fokker started his first completely original design. Due to its extensive wire bracing, Fokker called this first design Spinne (Spider).
The Spinne was a monoplane with flat horizontal tail and no vertical fin nor rudder. It was power by a 50 hp Argus engine cooled by side radiators. The monoplane wings had steel tubing framework, were swept back, and had significant dihedral for natural stability. Roll control was by wing warping. The 'fuselage' was formed of two wood longerons with wood cross braces that the engine was attached to. The pilot's seat was directly behind the engine. The general configuration was based on model gliders that Fokker had built.
For this first original design, Fokker was in partnership with Franc von Daum, who provided funding for the engine and contributed to building it. During Fokker's test hops with the machine a number of changes were made. To improve controllability a movable elevator was added, then a vertical rudder. However, when Fokker went home to Amsterdam for Christmas 1910, von Daum, who had been prevented from trying the aircraft, attempted to fly it and crashed into a tree. Spinne I was destroyed but the Argus engine survived.
Fokker then built a second, somewhat more advanced Spinne, using the 50 hp Argus engine from the first. This second Spinne was built in the workshop of Jacob Goedecker, another aviation pioneer who was also a qualified engineer. Goedecker assisted with detail design; however, the second Spinne was closely related to the first. Fokker fitted the second Spinne with ailerons instead of wing warping and fitted a rudder.
Fokker taught himself to fly in this second Spinne. After gaining some flight experience he requested a pilot's certificate, which he was granted on 7 June 1911 after passing the flight test.
As part of their agreement, von Daum was to get ownership of Spinne II as soon as Fokker had gained his flying license, and Fokker was to teach him to fly. Von Daum crashed the second Spinne while flying it. Fokker, meanwhile, had been building a third Spinne at the Goedecker workshop.