English Channel
but failed; in the same month, however, M. Blériot accomplished this great feat. Aeroplane races at Rheims, Berlin, Blackpool, &c.; many new records in distance and altitude; and the rapid development of aviation in France, England, Germany, the United States, and other countries marked the closing months of this wonderful year.
The Problem of Flight. - Such, in brief, is the history of aviation up to the present, and it shows that although some measure of success has been achieved, much still remains to be done. The many successful machines launched demonstrate that the navigation of the air is yet imperfectly understood, and the best achievements prove AERONAUTICS] that many limitations exist which tend to check further progress.
In studying the subject, perhaps the first great point to grasp is that practically any body can be propelled through the air provided it is given sufficient initial velocity to overcome the natural forces which tend to draw it down. The projectile fired from a big gun is in effect a form of flying machine, making a passage through the air by reason of its enormous velocity. As this speed declines, the shell takes a downward course, until finally it comes to earth. The aim of the flying-machine designer is to contrive an apparatus which will travel in the air with a small expenditure of power and at relatively slow speeds, thus obtaining more extended flight than if a very high speed were requisite, as in the case of projectiles. He therefore selects a light body, and gives this extended area, so as to derive increased support from the air. If we take a thin flat sheet of paper and a similar sheet which has been crumpled up to a small ball, it will be found, on dropping the two from a height, that the ball falls directly, whilst the sheet tends to go down in a zig-zag course, occupying more time, and falling to earth with less speed. By giving the ball horizontal velocity it will travel through the air like a projectile, whilst by imparting far less velocity to the flat sheet of paper it could be sent for a long distance through the air, did it not crumple up. A similar experiment, however, could be made with a flat thin plate of mica or aluminium.
Continuing this investigation further, it will be obvious that when the sheet of light material is dropped horizontally in still air its weight causes a downward pressure, and the air displaced curls upwards at its sides, producing an upward reaction. There is lifting effect here, but it is inferior to the downward pull of gravity on the sheet, and thus the latter glides gradually to earth.
Here we have vertical resistance of the air acting upwards, and the weight of the plane or sheet acting vertically downwards.
If, now, the sheet or plane be tilted upwards at a slight angle, it will, as it glides downwards, encounter horizontal resistance to a certain extent. This horizontal air resistance will strike the plane at an angle, and will give an inclined upward thrust in opposition to the downward pull of gravity.
FARMAN BIPLANE.
FARMAN PAULHAN MAH JUA M. PAULHAN BEFORE A FLIGHT.
I2 FARMAN BIPLANE.
M. ROGER SOMMER IN FLIGHT.
Could we contrive to make the aerial upward thrust greater than the downward pull, the plane would rise instead of fall, and, furthermore, it would move along a forward path. Here we get both support from the air, and horizontal motion at the same time. Obviously, the stronger the wind moving against the up-tilted plane the greater the lifting force will be; and the [AERONAUTICS problem in the aeroplane is to maintain this strong current of air blowing against the machine. The same resistance is created by moving the plane rapidly through the air as moving air at the same speed against the plane.
Experimenters with plane surfaces soon discovered that the size and shape of these surfaces had an important bearing on the problem. The bird's wing formation showed that it was better to have the machine of greater width in comparison to its length. Wenham and others then proved that the aeroplane made up of long narrow planes had many advantages.
The reason for this was not quite clear until some exact knowledge was obtained of what took place in the air when a plane surface was forced through it. The theory is now well established that the air, when met by the front edge of a plane surface, has a lifting effect, but this effect is only maintained for a very brief period in any given mass of air. The analogy of the skater gliding over thin ice may serve to make this clear. By moving rapidly from point to point, a skater may travel over ice which could not support him if he remained FARMAN BIPLANE.
M. FARMAN AT BLACKPOOL, OCT., 1909. 6 AERONAUTICS] for any appreciable period at one point.
He divides his pressure over a wide area when travelling quickly, and throws the strain on any particular part for only a very brief space of time.
So, too, the aeroplane, if it moves from one portion of air to another, will continue to find support, whilst if it remained stationary it would promptly sink to the ground just as the skater would sink through the ice. The "unbroken" air By placing another plane of the same shape above it, and a certain distance apart, an increased bearing surface is obtained, though at the expense of speed and other things. Thus experience and theory have shown that the double-deck aeroplane is a well-founded type. It can glide through the air for considerable distances, taking a very gentle downward path. The monoplane, having less bearing surface, will require more speed to keep it aloft, but is FARMAN BIPLANE.
M. GOBRON FLYING OVER PARIS. first struck by the aeroplane has a resistance which gives an upward force. It then divides up and breaks into many eddies, which travel to the back of the plane, and have little supporting value. naturally capable of higher speeds with the same power.
If we took a plane 40 ft. long by 7 ft. deep, and shot it through the air with the short side forward, it would have a maximum sustaining power only across its 7 ft. side, and it would soon come to the ground, unless the velocity was maintained very high. By projecting it with the long edge forward, it has sustaining power along the 40 ft. side, and a better gliding effect is obtained. Properly balanced and set at a slight upward angle, a plane of this size can make a very gradual glide through the air, thus showing that it derives considerable sustaining force from the atmosphere. By adding a motor which drives one or more propellers, we can force the machine through the air, and lead it from one section of air to another, so that with increasing speed the resistance of the atmosphere against the planes has an increased lifting effect, and the machine, instead of gliding down at a gentle angle, can be made to take an upward course. As the speed increases, so the machine will have increased lift, other things being equal. When the speed drops, this lift decreases, until finally a stage is reached at which the aeroplane drifts downwards, resting so long on each section of air that it drops a little ere the next section is passed to. Ultimately it reaches the ground at comparatively low velocity.
Thus the flying machine depends on its motor to keep aloft, and when the propulsive force ceases, the vessel glides to earth at an angle which depends on various circumstances. Some machines dash to the ground at a dangerous angle-that is to say, they have little true gliding power, whilst better designed instruments descend at a very gentle angle.
Birds have the power of soaring at certain times and places that is, they can apparently remain at the same altitude without moving their wings or exerting any power, [AERONAUTICS all those with fixed bearing surfaces of a geometrical shape, and which are practically made up of one continuous surface, as opposed to the movable wing-shaped machines, and those built up of many members. a In its present-day form the monoplane suggests the outstretched wings of gigantic bird, the central portion forming a covered-in body which contains the aviator, the motor, and the propelling mechanism. One or more vertical fins are fitted to increase stability, and there is usually a horizontal tail for giving upward FARMAN BIPLANE.
M. PAULHAN ABOUT TO START FROM LICHFIELD FOR MANCHESTER TO FINISH HIS SUCCESSFUL ATTEMPT TO WIN THE "DAILY MAIL" £10,000 PRIZE FOR A FLIGHT FROM LONDON TO MANCHESTER. and it has been urged that flying machines will be able to avail of the same conditions.
Types of Machines. - Having discussed the general principles of flight, we may now examine the different types of flying machines. They may be set out thus:- I. Monoplanes. 2. Biplanes. 3. Multiplanes. 4. Ornithopteres, or wing-like machines. 5. Helicopteres, and vertical lift machines. 6. Various combinations of these. 7. Combined balloons and aeroplanes.
Monoplanes. The monoplane is made up of a single main bearing surface which may be almost truly a plane, or be a curved surface, or take a modified wing formation.
Strictly speaking, no flying machine in use employs plane surfaces, as in well-nigh every case the surfaces are curved, and have appreciable thickness; but it has been found convenient to describe as plane machines and downward direction, whilst there is a vertical rudder for steering from side to side.
As typical of the monoplane class, the R.E.P. aeroplane designed by M. Esnault- Pelterie deserves close study. Its suggestiveness of bird-like form, coupled with the excellent workmanship displayed, render it notable, and it stands out as one of the few monoplanes, except that of M. Latham, which, up to the present, have made satisfactory flight. With its single plane the R.E.P. requires high engine speed ere it rises from the ground, but once in the air it travels at greater speed than most of the double-plane machines. The centre of the machine is made up of a girder frame from which the wings spring out gracefully. The rudder is mounted at the rear of the keel, and behind it is the elevator. The extremities of the main wings can be warped for steering and balancing. The engine and AERONAUTICS] propeller are mounted in front of the machine, which is thus drawn behind the propeller, instead of being pushed forward, as in the case of the double-plane machines.
Even more successful is the Blériot, the invention of M. Blériot, who may be regarded as the pioneer of monoplane flight. His machine is also of bird-like formation, and, by using high engine power, he has reduced the area of the machine to a remarkable degree. In recent trials he has carried one and two passengers, and thus has shown the extraordinary lifting power of his machine at high speed. His grandest achievement was the crossing of the English Channel. M. Santos Dumont has also carried the reduction of wing area almost to a fine art, but at the expense of stability, perhaps.
Extraordinary developments took place in June, 1909, when the Antoinette monoplane, driven by M. Hubert Latham, accomplished a series of records which placed it next in order of merit to the Wright biplane. Previously the monoplane had been able to make only short flights, and the opinion was held by rival aviators that it would never have the long-distance powers of the biplane. M. Latham, by his flight of 1 hr. 7 min. on June 5th, 1909, upset that theory, and showed the possibilities of the monoplane. Although of a newer type, the Antoinette has now surpassed the Blériot and R.E.P. monoplanes as regards time in the air, but M. Blériot has established a wonderful record by taking up two passengers with himself on a mono-