L.Opdyke French Aeroplanes Before the Great War (Schiffer)
In the 1908 Salon Tatin showed his next monoplane, this one sponsored by Louis Paulhan. It was a handsome development of his previous machine, and named Aero-Torpille No 1. The fuselage was now spindle-shaped ("spindle" in French is "fuseau," hence the word "fuselage"); the wings were again trapezoidal, very thin, set on the top of the fuselage, with Tatin elliptical dihedral. A device to adjust the angle of attack was patented at the end of 1911; it may have been fitted to Aero-Torpille No 1. The engine was inside the fuselage amidships, and a long drive-shaft turning on 5 bearings ran back to the tail-mounted propeller, kept off the ground by a long skid. The undercarriage had 2 wheels each attached at the bottom of inverted wooden arches, the axle running between them. It was reported to fly at about 145 kmh, but was difficult to control. (Bill Hannan, the famous Peanut-scale model-builder, reports that in a recent model meet the little Tatin model flew quicker and with more stability than any of the other models entered.) The fate of the aeroplane is not known, but features of it were copied afterwards - cf Riffard and Ruby, for instance, and Paulhan's Aero-Torpille of 1911.
(Span: 8.6 m; length: 8.6 m; wing area: 12.5 sqm; empty weight: 360 kg; 50 hp Gnome)
Flight, October 7, 1911.
Another unique machine, a creation of that well-known pioneer, Victor Tatin, has been undergoing tests at Louis Paulhan's flying ground. "The flying porpoise," as this machine is known in the locality where these experiments are being made, has many points in common with that monoplane exhibited at the 1909 Exhibition at Olympia by the Petre brothers. The pilot sits in advance of the main wings, practically enclosed in the fusiform body. Directly behind him revolves the Gnome engine, which is coupled by means of a hollow universally-jointed shaft to the propeller at the extreme end of the tail. The wings have up-turned tips.
Flight, January 6, 1912.
PARIS AERO SHOW.
Les Fils de Regy Freres.
THE most prominent exhibit on this stand was the aero torpedo of Paulhan and Tatin. This interesting machine, of which photographs have appeared from time to time in FLIGHT, is a sincere attempt on the part of the designers to gain greater speed and greater stability by the cutting down of as much head resistance as possible. The body itself is of excellent stream-line form, the fabric covering, which extends right from end to end, being supported on circular wooden hoops, which are applied over the fuselage proper of ordinary box-girder construction. The main peculiarity about the machine is that the propeller, a Regy Freres, is disposed at the extreme rear end of the main body, and is driven by means of a tubular steel shift by a Gnome engine of 50-h.p., situated just to the rear of the pilot. This shaft is not universally jointed, but rigid from motor to propeller. Very little camber and very little angle of incidence is evident in the wings, which are of an approximate elliptical plan form, and which are up-turned at the tips in order to endow the machine with a modicum of natural stability. It is interesting to note that no warping of the wings or any other method of maintaining lateral balance, other than by the inherent effect of the up-turned tips, is provided for, and this fact almost leads one to believe that Paulhan had in his mind visions of litigation with the Wright brothers, on which, by the way, he is at present engaged in the States. The tail surfaces consist of a horizontal flat plane, to the rear edge of which is hinged a pair of flaps, one on each side of the main body, which perform the function of elevators, while steering to the right and left is brought about by a vertical-balanced rudder mounted above the horizontal surface. Protection is afforded against damage to the propeller by a very high tail-skid.
The landing chassis is a very unique conception, and while being extremely strong and simple has the extra advantage of presenting little resistance to forward advance. The common axle connecting the two pneumatic-tyred disc wheels is rigidly attached to two roughly semi-circular sweeps of ash. These sweeps are hinged to the main body at their forward ends, and at their rear ends are connected by a piece of wood which in turn is strapped down to a reinforced fuselage cross-member with rubber cord. In this manner the shock-absorbing device is arranged in the interior of the fuselage, and in addition to resistance being reduced on this account, the system lends itself to extreme neatness and clearness of design.
As evidence of the advantages which are to be gained by the reduction of head resistance, it is interesting to mention that speeds of 88 miles per hour have been attained, presumably in still air, by this monoplane, and this with an engine of only 50 h.p. Besides this interesting monoplane, a full selection of beautifully constructed Regy Freres' propellers is exhibited on this stand.
Principal dimensions, &c. :-
Length 28 ft. Weight 800 lbs.
Span 28 ft. Speed 88 m.p.h.
Area 140 sq. ft. Motor 50-h.p. Gnome.
Price L 1,000.
Flight, February 17, 1912.
THE PAULHAN-TATIN AERO-TORPEDO.
IT is a universally recognised fact that, among the various machines that have come to light during the past year, none can lay claim to a greater measure of real sound originality than can the Aero-Torpedo of M. Victor Tatin. Throughout the whole machine there is an atmosphere indicating the extent of painstaking thought that must have been devoted to the development of each individual part and to the embodiment in sound constructional form of those purely aero-dynamical desiderata which up to the present constructors have avoided in view of the complications involved. Having faith in his convictions and ignoring the comments of "Freak," which greeted his enterprise when the rough details of the new machine he was constructing leaked out for the first time, he has proceeded with his experiments and produced a machine, which, by virtue of its excellent performances and extreme novelty, was the centre of interest at the last Paris Salon. Although the machine expresses so many novel ideas in aeroplane design, it is nevertheless a fact that its whole conception, excepting as regards the arrangement of the propeller, was established in the brain of M. Tatin as long ago as 33 years.
The most notable feature that becomes evident on first inspection is that, opposed to conventional monoplane practice the propeller, such in the true sense of the word, is arranged at the extreme rear end of the torpedo shaped body, where driven by a shaft some 20 ft. long, it revolves in the region of air disturbance that follows the passage of the machine and is so enabled to work with greater efficiency. The notion of placing the propeller at the rear occurred to Tatin something like twenty years since.
Apart from the number of craft of the genus canard in which this arrangement of the propeller is much more easily attainable, some few attempts have been made to effect this disposition in the past in connection with monoplane design, but as these experiments were in every case soon abandoned, it may be assumed that to Tatin belongs the credit of being the first to obtain any measure of success with this system. In England the enterprising Petre Brothers exhibited a monoplane incorporating this feature at the Olympia Aero Show in 1910, but the tests which followed had to be brought to a conclusion in view of the difficulties in the way of its successful application. At about the same time another monoplane of the canard type, but with its propeller shaft driven from the engine, situated in front of the pilot, made its appearance in France. Curiously enough it was the result of M. Armand Deperdussin's entrance into the arena of aeroplane construction, and in its production he had collaborated with M. Feure. For some time this machine was exhibited, suspended in the Central Hall of the famous Louvre Stores in Paris. Little was heard of its subsequent tests, and M. Deperdussin sought another solution to the problem of producing a successful and efficient monoplane. That he has succeeded in doing so is borne out by the popularity his machines at present enjoy.
First and foremost, in the design of the Aero-Torpedo, has been the aim to achieve efficiency by suppressing to as great an extent as possible, those individual parts of the machine which present resistance to forward advance and so absorb power without turning it to any practical advantage. The body itself, covered throughout its whole length by fabric is as near true stream-line form as can conveniently be obtained, and in its interior is mounted the engine, a Gnome, of 50 h.p. The pilot himself is seated so low in the body that only his head emerges.
An effort has been made to arrange as many organs as possible, which, in other machines present head resistance, in the interior of the fuselage. Thus the shock absorbing section of the landing chassis is disposed inside and the bottom pylone from which on most other machines the warping wires are taken, has been suppressed. What little warp is provided is operated by flat steel bands proceeding from the base of the body.
Everything exterior to the body has been most carefully shaped to stream-line form. The chassis itself, while being extraordinarily strong is extremely simple, and sections of it in the plane of flight are in every case very approximating to stream-line. The spun steel discs applied to the landing wheels and the belled-out aluminium cone which effects the final "run-off" of the propeller boss are indicative of the care which has been devoted even to lesser details to avoid head resistance losses.
The fabric covering of the main body is supported on light wooden hoops which surround the body proper, a lattice girder of the customary type, rectangular in section. So well has the workmanship been carried out that tests at the Arts et Metiers Institution have revealed its great strength to resist both torsional and flexional strains. Proving so rigid in this respect the constructors have abandoned the pair of universal joints with which the propeller shaft on the first model was furnished, and have adopted a simple tube for the purpose of connecting engine with the propeller. In order to prevent any "whip" in the shaft, it is slung at intervals along its length by six ball-bearings, each of them being strung in position by steel wires. Immediately behind the pilot, who sits in advance of the wings is mounted the motor, and the fabric covering of the fuselage in its vicinity is substituted by a louvred metal shield. This is made detachable so that the accessibility of the engine may not be interfered with. While the idea of the engine being arranged inside the fuselage is a very excellent one, we have some misgivings that in the case of air-cooled engines, trouble through over-heating is likely to be experienced, even with those of the rotary variety. The bench tests to which every engine leaving the Gnome works are subjected, fully demonstrate the capacity of the motor to keep perfectly cool by virtue of its revolution in still air and independent of any relative cooling draught due to forward motion. But in this case it would be working under entirely different conditions, and being enclosed to such an extent, with such little provision for ventilation, it is to be feared that it would soon attain a temperature not consistent with its efficient operation. However, we are assured that up to the present the engine has run with every satisfaction. At any rate, as far as the pilot is concerned, its proximity can be reckoned upon to afford him some measure of creature comfort on long distance flights in cold weather, although perhaps, its nearness would not be so appreciated should a heavy nose-landing happen.
In plan form, the wings may be represented by an ellipse with its tips cut away by lines parallel to its minor axis. In front elevation they have the appearance of an ellipse which has been cut by a line parallel to and below the major axis. This special wing shape is held by the designer to endow considerable natural lateral stability, and so convinced is he of its effectiveness that little or no warping has been provided for. While these upturned tips would certainly give the required result in calm weather, it is doubtful whether they will prove a sufficient guarantee of stability in disturbed air. In cross section they exhibit very little curvature, and what small amount of curvature is present bears a certain resemblance to that of the Nieuport wing. Similarly their angle of incidence is extremely small. Two double flat steel ribbons on each side of the body alone support the weight of the central unit in flight, the rear ribbon also serving to operate the wing warping.
At the rear end of the main body is arranged the tail, an organ almost identical in plan form with the wings. A purely directional flat surface plays the part of stabilizer and behind it is hinged the elevator, a pair of simple flaps operated by a crank arranged in the interior of the body. Mounted vertically above this surface is the directional rudder, balanced and approximately rectangular in shape. At the extreme rear is the propeller, a Regy Freres of 8 ft. pitch, which is protected against contact with the ground by a high skid. We should imagine that, it being impossible to lower the tail any appreciable amount, some difficulty would be met with in getting the machine to leave the ground quickly on attempting a flight. Conversely, it seems as though the machine, especially as it is credited with such high speed as 88 miles per hour would require an enormous length of ground in which to come to rest after landing. To modify this we would favour the adoption of some form of braking device, for the chances of always finding large spaces to alight on are scarcely to be relied upon.
The landing chassis is, as we have already remarked, one of extreme strength and simplicity. The common axle uniting the two wheels is attached to two arcs of hickory, a most suitable wood to use. At their forward extremity these arcs are hinged to the fuselage and at their rear end they are united by a strong piece of wood, which, in its turn, is strapped by means of cotton-covered rubber cord to a reinforced cross member of the lattice girder body. The cross bracing of the chassis can scarcely be accused of offering a great deal of head resistance for, to impart rigidity only six wires, they really should be termed light rods, are used; these passing through the arcs and tightened, Valkyrie fashion, by means of nuts and lock nuts on the outside. In common with a great many other machines to-day, especially those of modern origin, no attempt has been made to provide for the accommodation for a bodily sideways movement of the machine on landing.
Constituting, as this machine really does, a decided advance in aeronautical design it will be interesting to notice what effect these many innovations will have on future practice.