Hugo Byttebier - The Rise of the Flying Machine

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.

Hiram Maxim

Maxim started work on a real flying machine in 1889. In contrast to Ader’s secretiveness, Maxim was quite outspoken about his experiments. He regularly wrote articles in several magazines, talked freely about his projects and engaged in an extensive correspondence with Octave Chanute. Because of this, everybody who was interested knew how Maxim was getting on with solving the problems of human flight and it was easy to follow the progress of the construction of his aeroplane and of the tests he was carrying out.

By 1891, the machine had taken shape. It consisted of a steel construction which carried a huge rectangular wing of low aspect ratio which was built as a frame of steel tubes covered in silk. The wing was 110 ft long and 40 ft wide and, when completed, Maxim’s flying machine reached a length of 145 ft, the same length, curiously enough as Henson’s projected aeroplane of 1843.

At the sides of the machine four smaller wings of high aspect ratio projected outwards from the main frame. These small wings were set at a pronounced dihedral angle and were “used for keeping the equilibrium correct”. This meant that the machine was designed with inherent lateral stability because the small outside wings remained fixed as no ailerons or other artifices for changing the lateral position were provided. When the small stabilizing wings were attached, the machine looked like a huge biplane but the main wing consisted of the single 4,400 sq ft monoplane canvas. Its total wing surface was 5,550 sq ft.

The final completion of the machine was delayed because of Maxim’s manifold other activities and his constant trips to the US and also because of the work which was being carried out on the powerplant.

In fact, the most important part of a heavier-than-air flying machine is the powerplant and Maxim devoted much time and ingenuity to developing it. When finished, it was one of the wonders of its time. From a great quantity of steel tubes which had to be imported from France, Maxim built an enormous flash steam generator heated by an extraordinary number of jets (45,000 on the first design, later reduced to 7,500) which burned an inflammable mixture of naphtha and air. The generator was built for a steam pressure of 400 lbs/sq in., although in practice the maximum pressure used was 320 lbs/sq in. (Ader used a maximum of 220 lbs/sq in.). The steam, under high pressure, fed two big compound engines which at 375 rpm developed about 180 hp each. A condenser was included and the total weight of the machinery amounted to 1,800 lbs. When the necessary amounts of fuel and water were added, as well as the weight of three men who were to be on board, the total weight amounted to something over 5,000 lbs.

The first tests saw the machine rolling over a 1,800 foot long railway track with a 9 ft gauge laid out in his Baldwyn Park estate and, in order to prevent the craft from becoming airborne before its time, a heavy rolling railtruck was used to hold it down, adding another 3,000 lbs to the total weight.

In June 1892, Maxim published an article in which he explained how his machine was to be steered up or down. He wrote: “We should attach two long arms to our aeroplane in such a manner that they would project a considerable distance in the rear of the machine. To these arms we should pivot a very large and light silk-covered rudder and connect it with ropes so that it could be turned up or down by a small windlass from the machine. We should then take a run on the track and see if changing the angle of this rudder would increase or diminish the load on the forward or hind wheels. If we found that it would do this but not sufficiently so, we should attach another rudder in exactly the same manner to the forward end of the machine.”

Maxim was obviously more concerned with control than with stability in the longitudinal sense because, when the machine was ready, it effectively possessed two movable horizontal rudders (or elevators) one in front and one to the rear. For steering to the left or right a difference in the rotational speed of the airscrews was to be used and it is possible that this idea influenced Ader to some extent when he decided upon the use of his twin propellers on the “Avion III” of 1897.

The first rolling tests of Maxim’s flying machine were auspicious. It soon became clear that more than sufficient power was available because the craft could be accelerated to over 40 mph, more than enough to lift a craft loaded at 1 lbs/sq in. into the air. Maxim soon found that his machine was not only capable of lifting but that it was also incapable of being kept to the ground even when the heavy 3,000 lbs railcar was added to it and on one occasion during an experimental run in 1893 a sudden gust of wind lifted the plane off the ground, much to the alarm of the men aboard.

Maxim added another restraining device, which consisted of a double row of planks 30 ft apart and two ft above the ground. The machine was then fitted with outriggers carrying wheels that would come into contact with the planks from below as soon as the aeroplane rose more than the permitted two feet.

Experiments were then continued with increased boiler pressures, and consequently increased speeds, until on 31 July 1894, the pressure was raised to 320 lbs, which was calculated to be the equivalent of 365 hp. After a run of 600 ft, all the upper wheels were pushing against the restraining planks and after a further 300 ft the push became so great that one of the outrigger axles doubled up, a plank broke and the plane became free at the rear, causing even more alarm than the first time. Maxim quickly cut off steam and the plane settled down again, although rather badly damaged.