L.Opdyke French Aeroplanes Before the Great War (Schiffer)

Журнал Flight

Flight, November 16, 1912.

THE PARIS AERO SALON.

Moreau.

   HERE stands a 70-h.p. two-seater monoplane, interesting in that its longitudinal stability is arrived at by automatic means. It has two seats side by side built up in the form of a cage, which is swung pendulum fashion from the top member of the fuselage. It is connected to the tail, a plane surface shaped like a triangle with its apex clipped by a system of steel rods. The main idea of this system is that when the pendulum seat is hanging perpendicularly relative to the line of flight, the tail is in a position which makes for a horizontal flight path. Should the machine tend to climb, the pendulum seat changes its position relative to the rest of the machine and in doing so automatically readjusts the tail to restore the machine to normal level flight. Should the machine dip the same thing occurs, only of course in the opposite sense. Employing a system of this type it is, of course, necessary to have supplementary elevator controls to carry out such manoeuvres as ascending and descending. This, on the Moreau machine, is effected by an auxiliary lever to the right of the pilot. The machine's lateral stability is to a certain extent natural owing to the design of the wings, but further control is maintained by a lever projecting downward from the framework above, operating ailerons. By M. Moreau's system it is possible to cut the automatic device out of action and maintain control simply by the use of the levers. Improvements have been made on the first model with which M. Moreau experimented. He found that, should the engine stop in mid-air, the pilot's seat swung forward with its own inertia and set the tail for ascent - a very uncomfortable position to find oneself in with one's engine stopped. On the present machine he has fitted a device which detects any tendency on the part of the pendulum seat to swing forward by virture of its inertia, and which immediately locks the pendulum seat, thus preventing the machine from getting cabre owing to engine stoppage. He has found, too, that if the machine encounters a strong gust head on there is a similar tendency for the monoplane to assume a cabre attitude. To obviate this, a small aluminium plate is fitted in front of the body normally to the relative wind, which plate detects any sudden gust and locks the pendulum seat. From a constructional point of view the machine does not possess a great deal of interest, excepting in its chassis which is extremely flexible. The skids themselves are mounted so that they may give fore and aft, parallel to the bottom members of the body, against the restraint of shock absorbers.


Flight, October 4, 1913.

The Bonnet "Stability" Prize Won by Moreau.

   ALTHOUGH the winning of the Bonnet prize by M. Moreau, on the 24th ult., at Melun, may be taken as a good example of compliance with the rules governing the contests for such prizes, it is hardly correct to describe the performance as a demonstration of the complete automatic stability of the machine. The conditions called for a flight of 20 kiloms. in a wind blowing 15 m.p.h. without the pilot touching the control lever with his hands. Nothing was stipulated with regard to the use of the rudder and apparently during the above performance the pilot kept his feet very busy on the rudder bar, judging from a signed report furnished by M. Charles Lafon, the official observer. He says :- "Le pilote vola vingt-cinq minutes les bras croises. Ah! certes, le probleme de la stabilisation automatique n'est pas resolu, car Moreau travailla dur avec ses pieds, non settlement pour faire les virages, mais aussi pour corriger."
   It would appear to be highly desirable that when the Ligue Nationale Aerienne are again drawing up rules for such prizes as this they should seek a little expert advice. At the same time, we must congratulate M. Moreau on securing the prize although in doing so he appears to have given the observer who had to accompany him a pretty busy time.


Flight, December 13, 1913.

THE STANDS AT THE PARIS AERO SHOW.

MOREAU.

   On the Emaillite stand is shown the Moreau monoplane of which so much has been heard through the winning of the Bonnet stability prize. This machine, it will be remembered, is made automatically stable longitudinally by having the pilot's seat slung pendulum fashion underneath the wings. These are - on this particular machine - covered with a transparent Emaillite preparation which is expected to render the machine practically invisible when flying at a good height, as the spars and ribs and the nacelle will be the only objects which can be seen.


Flight, January 10, 1914.

THE PARIS AERO SALON - 1913.

MOREAU.

   On the Emaillite stand was shown the Moreau aerostable, which, it will be remembered, won the Bonnet stability prize. The whole machine seemed unnecessarily complicated, consisting, as it did, of a veritable forest of steel tubes. The automatic stability was purely longitudinal, the shape of the wings being supposed to render the machine automatically stable laterally, although ailerons are fitted. This lateral stability was greatly increased by judicious use of the rudder, as it is quite possible to keep a machine on an even keel without the use of the warp simply by increasing the speed of the dropping wing by turning the machine in the opposite direction. As for the automatic longitudinal stability, this is possessed by nearly every well-designed machine, and is secured simply by means of the longitudinal dihedral angle formed by the difference in the angle of incidence of the wings and the tail plane. In any case one would think that this longitudinal control by means of slinging the pilot's seat could be obtained in a much simpler way.
   Constructionally the machine was built of steel almost throughout, the pilot's seat being slung by means of steel tubes underneath the main planes, thus giving the machine a very low centre of gravity.
   This was partly counteracted by mounting the engine up in front of and on a level with the leading edge of the wings. On top of the wings was mounted the petrol tank, from which petrol is fed to the carburettor by gravity. The engine was partly covered by an aluminium shield enclosing the lower part of the engine, whilst the upper part had been left uncovered for cooling purposes.


Flight, January 17, 1914.

INVISIBLE AEROPLANES.

   ONE important point which the designer of a military aeroplane has to keep in mind is that his machine, when in the air, must be as hard to discern as possible. There have been several attempts to build an aeroplane with the wings of transparent material, and in May and June of 1912, Lieut. Nittner was flying at Wiener Neustadt, near Vienna, an Etrich monoplane, specially built on such lines for Capt. Petroczy, formerly commandant of the flying corps in the Austrian Army. This machine had the planes covered with a special variety of Emaillite cellulose sheets, and the system has since been developed and patented in all countries by MM. Leduc Heitz, of the Paris House of Emaillite. A photograph is reproduced of the Etrich machine, to which reference has been made, and which those present on the ground were unable to locate in the air when flying at an altitude of between 900 and 1,200 ft. It is stated that at a height of 700 ft. only the framework is dimly visible, and this and the outline of the motor and pilot and passengers present so small an area to rifle or gun fire, that at the rate of speed at which aeroplanes are flown to-day, accurate aiming at such surfaces becomes nearly impossible. There are also secondary advantages in the use of such transparent sheeting in the construction of aeroplanes. For one thing, it enables the pilot to keep an eye upon the interior framework of the planes, and to detect at once any straining or fracture of the ribs, &c. Another advantage is that the highly polished smooth surface reduces the friction, as was proved in the case of Capt. Petroczy's machine, although, as that was the first machine to be so treated, the material used was not so suitable as the latest product. The surface could not be properly tightened, and owing to the sheeting being more or less plastic it presented a wavy surface, while some difficulty was experienced in securely fastening it to the ribs.
   As long ago as 1904. Prof. Reisner, of Aachen, suggested that polished celluloid should be utilised for aeroplane sheeting in order to diminish air friction.
   Last year, M. W. A. Lebedeff, working in conjunction with the Russian Government, tried to cover a Henry Farman biplane with transparent cellulose sheeting of a somewhat modified composition. This material was not so heavy as that used in Austria, and it was also somewhat stronger (its tensile strength being about 7 kilogs. Per square millimetre of section), but the wavy surface of the wings, due to the flexibility of the material, could not be overcome.
   After working at the problem for some time the Emaillite firm have developed a better material which was seen at the Paris Show on the planes of the Moreau monoplane. Instead of using ordinary cellulose sheeting, this machine has what might be termed a reinforced sheeting consisting of two layers of Emaillite with a sheet of silk tulle between them, the tulle being specially treated to render it transparent. That the material is to all intents and purposes transparent is illustrated by the photographs of one of the wings of the Moreau monoplane behind which a man can be clearly seen. The use of the tulle liner not only strengthens the material but it also prevents it sagging or warping between the ribs so that by its use it is quite possible to obtain a smooth and regular surface on the planes. The tensile strength of the material is about nine to ten kilogs. per square millimeter section and a 35 mm. sheeting is sufficient to ensure a tensile strength of about 2,800 to 3,000 kilogs. of the wing covering, a stress which is never attained with the best fabrics in use. The weight of this new Emaillite material does not exceed 375 grammes per square metre, which is but 40 per cent, more than the weight of good doped linen fabric as generally used, so that the increase of weight in the case of ordinary machines would be between 12 and 15 kilogs. It is claimed for this new Emaillite transparent reinforced sheeting that it has all the advantages of that which is not reinforced without its faults. It can be fastened either by nailing, sewing, or by using an adhesive solution. It will not tear or break when anything such as a tool falls upon it, while should it be pierced by a bullet the fabric liner would prevent the damage extending. The British patents for this invention are held by the British Emaillite Co., Ltd., of 30, Regent Street, W. Extensive tests are shortly to be carried out with machines covered in this way, in order to ascertain the height at which they become virtually invisible.