CHAPTER XXI
The Internal-combustion Engine(Cont.)
I suppose many of my readers are quite familiar with the working of a steam-engine. Probably you have owned models of steam-engines right from your earliest youth, and there are few boys who do not know how the railway engine works.
But though you may be quite familiar with the mechanism of this engine, it does not follow that you know how the petrol engine works, for the two are highly dissimilar. It is well, therefore, that we include a short description of the internal-combustion engine such as is applied to motor-cars, for then we shall be able to understand the principles of the aeroplane engine.
At present petrol is the chief fuel used for the motor engine. Numerous experiments have been tried with other fuels, such as benzine, but petrol yields the best results.
Petrol is distilled from oil which comes from wells bored deep down in the ground in Pennsylvania, in the south of Russia, in Burma, and elsewhere. Also it is distilled in Scotland from oil shale, from which paraffin oil and wax and similar substances are produced. When the oil is brought to the surface it contains many impurities, and in its native form is unsuitable for motor engines. The crude oil is composed of a number of different kinds of oil; some being light and clear, others heavy and thick.
To purify the oil it is placed in a large metal vessel or "still". Steam is first passed over the oil in the still, and this changes the lightest of the oils into vapours. These vapours are sent through a series of pipes surrounded with cold water, where they are cooled and become liquid again. Petrol is a mixture of these lighter products of the oil.
If petrol be placed in the air it readily turns into a vapour, and this vapour is extremely inflammable. For this reason petrol is always kept in sealed tins, and very large quantities are not
allowed to be stored near large towns. The greatest care has to be exercised in the use of this "unsafe" spirit. For example, it is most dangerous to smoke when filling a tank with petrol, or to use the spirit near a naked light. Many motor-cars have been set on fire through the petrol leaking out of the tank in which it is carried.
The tank which contains the petrol is placed under one of the seats of the motor-car, or at the rear; if in use on a motor-cycle it is arranged along the top bar of the frame, just in front of the driver. This tank is connected to the "carburettor", a little vessel having a small nozzle projecting upwards in its centre. The petrol trickles from the tank into the carburettor, and is kept at a constant level by means of a float which acts in a very similar way to the ballcock of a water cistern.
The carburettor is connected to the cylinder of the engine by another pipe, and there is valve which is opened by the engine itself and is closed by a spring. By an ingenious contrivance the valve is opened when the piston moves out of the cylinder, and a vacuum is created behind it and in the carburettor. This carries a fine spray of petrol to be sucked up through the nozzle. Air is also sucked into the carburettor, and the mixture of air and petrol spray produces an inflammable vapour which is drawn straight into the cylinder of the engine.
As soon as the piston moves back, the inlet valve is automatically closed and the vapour is compressed into the top of the cylinder. This is exploded by an electric spatk, which is passed between two points inside the cylinder, and the force of the explosion drives the piston outwards again. On its return the "exhaust" or burnt gases are driven out through another valve, known as the "exhaust" valve.
Whether the engine has two, four, or six cylinders, the car is propelled in a similar way for all the pistons assist in turning one shaft, called the engine shaft, which runs along the centre of the car to the back axle.
The rapid explosions in the cylinder produce great heat, and the cylinders are kept cool by circulating water round them. When the water has become very hot it passes through a number of pipes, called the "radiator", placed in front of the car; the cold air rushing between the coils cools the water, so that it can be used over and over again.
No water is needed for the engine of a motor cycle. You will notice that the cylinders are enclosed by wide rings of metal, and these rings are quite sufficient to radiate the heat as quickly as it is generated.
CHAPTER XXII
The Aeroplane Engine
We have seen that a very important part of the internal-combustion engine, as used on the motor-car, is the radiator, which prevents the engine from becoming overheated and thus ceasing to work. The higher the speed at which the engine runs the hotter does it become, and the greater the necessity for an efficient cooling apparatus.
But the motor on an aeroplane has to do much harder work than the motor used for driving the motor-car, while it maintains a much higher speed. Thus there is an even greater tendency for it to become overheated; and the great problem which inventors of aeroplane engines have had to face is the construction of a light but powerful engine equipped with some apparatus for keeping it cool.
Many different forms of aeroplane engines have been invented during the last few years. Some inventors preferred the radiator system of cooling the engine, but the tank containing the water, and the radiator itself, added considerably to the weight of the motor, and this, of course, was a serious drawback to its employment.
But in 1909 there appeared a most ingeniously-constructed engine which was destined to take a very prominent part in the progress of aviation. This was the famous "Gnome" engine, by means of which races almost innumerable have been won, and amazing records established.
We have already referred to the engine shaft of the motor-car, which is revolved by the pistons of the various fixed cylinders. In all aeroplane engines which had appeared before the Gnome the same principle of construction had been adopted; that is to say, the cylinders were fixed, and the engine shaft revolved.
But in the Gnome engine the reverse order of things takes place; the shaft is fixed, and the cylinders fly round it at a tremendous speed. Thus the rapid whirl in the air keeps the engine cool, and cumbersome tanks and unwieldy radiators can be dispensed with. This arrangement enabled the engine to be made very light and yet be of greater horse-power than that attained
by previously-existing engines.
A further very important characteristic of the rotary-cylinder engine is that no flywheel is used; in a stationary engine it has been found necessary to have a fly-wheel in addition to the propeller. The rotary-cylinder engine acts as its own fly-wheel, thus again saving considerable weight.
The new engine astonished experts when they first examined it, and all sorts of disasters to it were predicted. It was of such revolutionary design that wiseacres shook their heads and said that any pilot who used it would be constantly in trouble with it. But during the last few years it has passed from one triumph to another, commencing with a long-distance record established by Henri Farman at Rheims, in 1909. It has since been used with success by aviators all the world over. That in the Aerial Derby of 1913--which was flown over a course Of 94 miles around London--six of the eleven machines which took part in the race were fitted with Gnome engines, and victory was achieved by Mr. Gustav Hamel, who drove an 80-horse-power Gnome, is conclusive evidence of the high value of this engine in aviation.
CHAPTER XXIII
A Famous British Inventor of Aviation Engines
In the general design and beauty of workmanship involved in the construction of aeroplanes, Britain is now quite the equal of her foreign rivals; even in engines we are making extremely rapid progress, and the well-known Green Engine Company, profiting by the result of nine years' experience, are able to turn out aeroplane engines as reliable, efficient, and as light in pounds weight per horse-power as any aero engine in existence.
In the early days of aviation larger and better engines of British make specially suited for aeroplanes were our most urgent need.
The story of the invention of the "Green" engine is a record of triumph over great difficulties.
Early in 1909--the memorable year when M. Bleriot was firing the enthusiasm of most engineers by his cross-Channel flight; when records were being established at Rheims; and when M. Paulhan won the great prize of L10,000 for the London to Manchester flight-- Mr. Green conceived a number of ingenious ideas for an aero engine.
One of Mr. Green's requirements was that the cylinders should be made of cast-steel, and that they should come from a British foundry. The company that took the work in hand, the Aster Company, had confidence in the inventor's ideas. It is said that they had to waste 250 castings before six perfect cylinders were produced. It is estimated that the first Green engine cost L6000. These engines can be purchased for less than L500.
The closing months of 1909 saw the Green engine firmly established. In October of that year Mr. Moore Brabazon won the first all-British competition of L1000 offered by the Daily Mail for the first machine to fly a circular mile course. His aeroplane was fitted with a 60-horse-power Green aero engine. In the same year M. Michelin offered L1000 for a long-distance flight in all-British aviation; this prize was also won by Mr. Brabazon, who made a flight of 17 miles.
Some of Colonel Cody's achievements in aviation were made with the Green engine. In 1910 he succeeded in winning both the duration and cross-country Michelin competitions, and in 1911 he again accomplished similar feats. In this year he also finished fourth in the all-round-Britain race. This was a most meritorious performance when it is remembered that his Cathedral weighed nearly a ton and ahalf, and that the 60-horse-power Green was practically "untouched", to use an engineering expression, during the whole of the 1010-mile flight.
The following year saw Cody winning another Michelin prize for a cross-country competition. Here he made a flight of over 200 miles, and his high opinion of the engine may be best described in the letter he wrote to the company, saying: "If you kept the engine supplied from without with petrol and oil, what was within would carry you through".
But the pinnacle of Mr. Green's fame as an inventor was reached in 1913, when Mr. Harry Hawker made his memorable waterplane flight from Cowes to Lough Shinny, an account of which appears in a later chapter. His machine was fitted with a 100-horse-power Green, and with it he flew 1043 miles of the 1540-miles course.
Though the complete course was not covered, neither Mr. Sopwith-- who built the machine and bore the expenses of the flight—nor Mr. Hawker attached any blame to the engine. At a dinner of the Aero Club, given in 1914, Mr. Sopwith was most enthusiastic in discussing the merits of the "Green", and after Harry Hawker had recovered from the effects of his fall in Lough Shinny he remarked in reference to the engine: "It is the best I have ever met. I do not know any other that would have done anything like the work."
At the same time that this race was being held the French had a competition from Paris to Deauville, a distance of about 160 miles. When compared with the time and distance covered by Mr. Hawker, the results achieved by the French pilots, flying machines fitted with French engines, were quite insignificant; thus proving how the British industry had caught up, and even passed, its closest rivals.
In 1913 Mr. Grahame White, with one of the 100-horse-power "Greens" succeeded in winning the duration Michelin with a flight of over 300 miles, carrying a mechanic and pilot, 85 gallons of petrol, and 12 gallons of lubricating oil. Compulsory landings were made every 63 miles, and the engine was stopped. In spite of these trying conditions, the engine ran, from start to finish, nearly nine hours without the slightest trouble.
Sufficient has been said to prove conclusively that the thought and labour expended in the perfecting of the Green engine have not been fruitless.
CHAPTER XXIV
The Wright Biplane (Camber of Planes)
Now that the internal-combustion engine had arrived, the Wrights at once commenced the construction of an aeroplane which could be driven by mechanical power. Hitherto, as we have seen, they had made numerous tests with motorless gliders; but though these tests gave them much valuable information concerning the best methods of keeping their craft on an even keel while in the air, they could never hope to make much progress in practical flight until they adopted motor power which would propel the machine through the air.
We may assume that the two brothers had closely studied the engines patented by Daimler and Levassor, and, being of a mechanical turn of mind themselves, they were able to build their own motor, with which they could make experiments in power-driven flight.
Before we study the gradual progress of these experiments it would be well to describe the Wright biplane. The illustration facing p. 96 shows a typical biplane, and though there are certain modifications in most modern machines, the principles upon which it was built apply to all aeroplanes.
The two main supporting planes, A, B, are made of canvas stretched tightly across a light frame, and are slightly curved, or arched, from front to back. This curve is technically known as the CAMBER, and upon the camber depend the strength and speed of the machine.
If you turn back to Chapter XVII you will see that the plane is modelled after the wing of a bird. It has been found that the lifting power of a plane gradually dwindles from the front edge-- or ENTERING EDGE, as it is called--backwards. For this reason it is necessary to equip a machine with a very long, narrow plane, rather than with a comparatively broad but short plane.
Perhaps a little example will make this clear. Suppose we had two machines, one of which was fitted with planes 144 feet long and 1 foot wide, and the other with planes 12 feet square. In the former the entering edge of the plane would be twelve times as great as in the latter, and the lifting power would necessarily be much greater. Thus, though both machines have planes of the same area, each plane having a surface of 144 square feet, yet there is a great difference in the "lift" of the two.
But it is not to be concluded that the back portion of a plane is altogether wasted. Numerous experiments have taught aeroplane constructors that if the plane were slightly curved from front to back the rear portion of the plane also exercised a "lift"; thus, instead of the air being simply cut by the entering edge of the plane, it is driven against the arched back of the plane, and
helps to lift the machine into the air, and support it when in flight.
There is also a secondary lifting impulse derived from this simple curve. We have seen that the air which has been cut by the front edge of the plane pushes up from below, and is arrested by the top of the arch, but the downward dip of the rear portion of the plane is of service in actually DRAWING THE AIR FROM ABOVE. The rapid air stream which has been cut by the entering edge passes above the top of the curve, and "sucks up", as it were, so that the whole wing is pulled upwards. Thus there are two lifting impulses: one pushing up from below, the other sucking up from above.
It naturally follows that when the camber is very pronounced the machine will fly much slower, but will bear a greater weight than a machine equipped with planes having little or no camber. On high-speed machines, which are used chiefly for racing purposes, the planes have very little camber. This was particularly noticeable in the monoplane piloted by Mr. Hamel in the Aerial Derby of 1913: the wings of this machine seemed to be quite flat, and it was chiefly because of this that the pilot was able to maintain such marvellous speed.
The scientific study of the wing lift of planes has proceeded so far that the actual "lift" can now be measured, providing the speed of the machine is known, together with the superficial area of the planes. The designer can calculate what weight each square foot of the planes will support in the air. Thus some machines have a "lift" of 9 or 10 pounds to each square foot of wing surface, while others are reduced to 3 or 4 pounds per square foot.
CHAPTER XXV
The Wright Biplane (Cont.)
The under part of the frame of the Wright biplane, technically known as the CHASSIS, resembled a pair of long "runner" skates, similar to those used in the Fens for skating races. Upon those runners the machine moved along the ground when starting to fly. In more modern machines the chassis is equipped with two or more small rubber-tyred wheels on which the machine runs along the ground before rising into the air, and on which it alights when a descent is made.
You will notice that the pilot's seat is fixed on the lower plane, and almost in the centre of it, while close by the engine is mounted. Alongside the engine is a radiator which cools the water that has passed round the cylinder of the engine in order to prevent them from becoming overheated.
Above the lower plane is a similar plane arranged parallel to it, and the two are connected by light upright posts of hickory wood known as STRUTS. Such an aeroplane as this, which is equipped with two main planes, known as a BIPLANE. Other types of air-craft are the MONOPLANE, possessing one main plane, and the TRIPLANE, consisting of three planes. No practical machine has been built with more than three main planes; indeed, the triplane is now almost obsolete.
The Wrights fitted their machine with two long-bladed wooden screws, or propellers, which by means of chains and sprocket-wheels, very like those of a bicycle, were driven by the engine, whose speed was about 1200 revolutions a minute. The first motor engine used by these clever pioneers had four cylinders, and developed about 20 horsepower. Nowadays engines are produced which develop more than five times that power.
In later machines one propeller is generally thought to be sufficient; in fact many constructors believe that there is danger in a two-propeller machine, for if one propeller got broken, the other propeller, working at full speed, would probably overturn the machine before the pilot could cut off his engine.
Beyond the propellers there are two little vertical planes which can be moved to one side or the other by a control lever in front of the pilot's seat. These planes or rudders steer the machine from side to side, answering the same purpose as the rudder of a boat.
In front of the supporting planes there are two other horizontal planes, arranged one above the other; these are much smaller than the main planes, and are known as the ELEVATORS. Their function is to raise or lower the machine by catching the air at different angles.
Comparison with a modern biplane, such as may be seen at an aerodrome on any "exhibition" day, will disclose several marked differences in construction between the modern type and the earlier Wright machine, though the central idea is the same.
CHAPTER XXVI
How the Wrights launched their Biplane
Those of us who have seen an aeroplane rise from the ground know that it runs quickly along for 50 or 60 yards, until sufficient momentum has been gained for the craft to lift itself into the air. The Wrights, as stated, fitted their machine with a pair of launching runners which projected from the under side of the lower plane like two very long skates, and the method of launching their craft was quite different from that followed nowadays.
The launching apparatus consisted of a wooden tower at the starting end of the launching ways--a wooden rail about 60 or 70 feet in length. To the top of the tower a weight of about ½ ton was suspended. The suspension rope was led downwards over pulleys, thence horizontally to the front end and back to the inner end of the railway, where it was attached to the aeroplane. A small trolley was fitted to the chassis of the machine and this ran along the railway.
To launch the machine, which, of course, stood on the rail, the propellers were set in motion, and the 1/2-ton weight at the top of the tower was released. The falling weight towed the aeroplane rapidly forward along the rail, with a velocity sufficient to cause it to glide smoothly into the air at the other end of the launching ways. By an ingenious arrangement the trolley was left behind on the railway.
It will at once occur to you that there were disadvantages in this system of commencing a flight. One was that the launching apparatus was more or less a fixture. At any rate it could not be carried about from place to place very readily: Supposing the biplane could not return to its starting-point, and the pilot was forced to descend, say, 10 or 12 miles away: in such a case it would be necessary to tow the machine back to the launching ways, an obviously inconvenient arrangement, especially in unfavourable country.
For some time the "wheeled" chassis has been in universal use, but in a few cases it has been thought desirable to adopt a combination of runners and wheels. A moderately firm surface is necessary for the machine to run along the ground; if the ground be soft or marly the wheels would sink in the soil, and serious accidents have resulted from the sudden stoppage of the forward motion due to this cause.
With their first power-driven machine the Wrights made a series of very fine flights, at first in a straight line. In 1904 they effected their first turn. By the following year they had made such rapid progress that they were able to exceed a distance of 20 miles in one flight, and keep up in the air for over half an hour at a time. Their manager now gave their experiments great publicity, both in the American and European Press, and in 1908 the brothers, feeling quite sure of their success, emerged from a self-imposed obscurity, and astonished the world with some wonderful flights, both in America and on the French flying ground at Issy.
A great loss to aviation occurred on 30th May, 1912, when Wilbur Wright died from an attack of typhoid fever. His work is officially commemorated in Britain by an annual Premium Lecture, given under the auspices of the Aeronautical Society.
CHAPTER XXVII
The First Man to Fly in Europe
In November, 1906, nearly the whole civilized world was astonished to read that a rich young Brazilian aeronaut, residing in France, had actually succeeded in making a short flight, or, shall we say, an enormous "hop", in a heavier-than-air machine.
This pioneer of aviation was M. Santos Dumont. For five or six years before his experiments with the aeroplane he had made a great many flights in balloons, and also in dirigible balloons. He was the son of well-to-do parents--his father was a successful coffee planter--and he had ample means to carry on his costly experiments.
Flying was Santos Dumont's great hobby. Even in boyhood, when far away in Brazil, he had been keenly interested in the work of Spencer, Green, and other famous aeronauts, and aeronautics became almost a passion with him.
Towards the end of the year 1898 he designed a rather novel form of air-ship. The balloon was shaped like an enormous cigar, some 80 feet long, and it was inflated with about 6000 cubic feet of hydrogen. The most curious contrivance, however, was the motor. This was suspended from the balloon, and was somewhat similar to the small motor used on a motor-cycle. Santos Dumont sat beside this motor, which worked a propeller, and this curious craft was
guided several times by the inventor round the Botanical Gardens in Paris.
About two years after these experiments the science of aeronautics received very valuable aid from M. Deutsch, a member of the French Aero Club. A prize of about L4000 was offered by this gentleman to the man who should first fly from the Aero Club grounds at Longchamps, double round the Eiffel Tower, and then sail back to the starting-place. The total distance to be flown was rather more than 3 miles, and it was stipulated that the journey--which could be made either in a dirigible air-ship or a flying machine--should be completed within half an hour.
This munificent offer at once aroused great enthusiasm among aeronauts and engineers throughout the whole of France, and, to a lesser degree, in Britain. Santos Dumont at once set to work on another air-ship, which was equipped with a much more powerful motor than he had previously used. In July, 1901, his arrangements were completed, and he made his first attempt to win the prize.
The voyage from Longchamps to the Eiffel Tower was made in very quick time, for a favourable wind speeded the huge balloon on its way. The pilot was also able to steer a course round the tower, but his troubles then commenced. The wind was now in his face, and his engine-a small motor engine of about 15 horse-power-was unable to produce sufficient power to move the craft quickly against the wind. The plucky inventor kept fighting against the-breeze, and at length succeeded in returning to his starting-point; but he had exceeded the time limit by several minutes and thus, was disqualified for the prize.
Another attempt was made by Santos Dumont about a month later. This time, however, he was more unfortunate, and he had a marvellous escape from death. As on the previous occasion he got into great difficulties when sailing against the wind on the return journey, and his balloon became torn, so that the gas escaped and the whole craft crashed down on the house-tops. Eyewitnesses of the accident expected to find the gallant young Brazilian crushed to death; but to their great relief he was seen to be hanging to the car, which had been caught upon the buttress of a house. Even now he was in grave peril, but after a long delay he was rescued by means of a rope.
It might be thought that such an accident would have deterred the inventor from making further attempts on the prize; but the aeronaut seemed to be well endowed with the qualities of patience and perseverance and continued to try again. Trial after trial was made, and numerous accidents took place. On nearly every occasion it was comparatively easy to sail round the Tower, but it was a much harder task to sail back again.
At length in October, 1901, he was thought to have completed the course in the allotted time; but the Aero Club held that he had exceeded the time limit by forty seconds. This decision aroused great indignation among Parisians--especially among those who had watched the flight--many of whom were convinced that the journey had been accomplished in the half-hour. After much argument the committee which had charge of the race, acting on the advice of M. Deutsch, who was very anxious that the prize should be awarded to Santos Dumont, decided that the conditions of the flight had been complied with, and that the prize had been legitimately won.
It is interesting to read that the famous aeronaut divided the money among the poor.
But important though Santos Dumont's experiments were with the air-ship, they were of even greater value when he turned his attention to the aeroplane.
One of his first trials with a heavier-than-air machine was made with a huge glider, which was fitted with floats. The curious craft was towed along the River Seine by a fast motor boat named the Rapiere, and it actually succeeded in rising into the air and flying behind the boat like a gigantic kite.
12th November, 1906, is a red-letter day in the history of aviation, for it was then that Santos Dumont made his first little flight in an aeroplane. This took place at Bagatelle, not far from Paris.
Two months before this the airman had succeeded in driving his little machine, called the Bird of Prey, many yards into the air, and "11 yards through the air", as the newspapers reported; but the craft was badly smashed. It was not until November that the first really satisfactory flight took place.
A description of this flight appeared in most of the European newspapers, and I give a quotation from one of them: "The aeroplane rose gracefully and gently to a height of about 15 feet above the earth, covering in this most remarkable dash through the air a distance of about 700 feet in twenty-one seconds.
"It thus progressed through the atmosphere at the rate of nearly 30 miles an hour. Nothing like this has ever been accomplished before. . . . The aeroplane has now reached the practical stage."
The dimensions of this aeroplane were:
Length 32 feet
Greatest width 39 feet
Weight with one passenger 465 pounds.
Speed 30 miles an hour
A modern aeroplane with airman and passenger frequently weighs over 1 ton, and reaches a speed of over 60 miles an hour.
It is interesting to note that Santos Dumont, in 1913--that is, only seven years after his flight in an aeroplane at Bagatelle made him world-famous--announced his intention of again taking an active part in aviation. His purpose was to make use of aeroplanes merely for pleasure, much as one might purchase a motor-car for the same object.
Could the intrepid Brazilian in his wildest dreams have foreseen the rapid advance of the last eight years? In 1906 no one had flown in Europe; by 1914 hundreds of machines were in being, in which the pilots were no longer subject to the wind's caprices, but could fly almost where and when they would.
Frenchmen have honoured, and rightly honoured, this gallant and picturesque figure in the annals of aviation, for in 1913 a magnificent monument was unveiled in France to commemorate his pioneer work.
CHAPTER XXVIII
M. Bleriot and the Monoplane
If the Wright brothers can lay claim to the title of "Fathers of the Biplane", then it is certain that M. Bleriot, the gallant French airman, can be styled the "Father of the Monoplane."
For five years--1906 to 1910--Louis Bleriot's name was on everybody's lips in connection with his wonderful records in flying and skilful feats of airmanship. Perhaps the flight which brought him greatest renown was that accomplished in July, 1909, when he was the first man to cross the English Channel by aeroplane. This attempt had been forestalled, although unsuccessfully, by Hubert Latham, a daring aviator who is best known in Lancashire by his flight in 1909 at Blackpool in a wind which blew at the rate of nearly 40 miles an hour—a performance which struck everyone with wonder in these early days of aviation.
Latham attempted, on an Antoinette monoplane, to carry off the prize of L1000 offered by the proprietors of the Daily Mail. On the first occasion he fell in mid-Channel, owing to the failure
of his motor, and was rescued by a torpedo-boat. His machine was so badly damaged during the salving operations that another had to be sent from Paris, and with this he made a second attempt, which was also unsuccessful. Meanwhile M. Bleriot had arrived on the scene; and on 25th July he crossed the Channel from Calais to Dover in thirty-seven minutes and was awarded the L1000 prize.
Bleriot's fame was now firmly established, and on his return to France he received a magnificent welcome. The monoplane at once leaped into favour, and the famous "bird man" had henceforth to confine his efforts to the building of machines and the organization of flying events. He has since established a large factory in France and inaugurated a flying school at Pau.
All the time that the Wrights were experimenting with their glider and biplane in America, and the Voisin brothers were constructing biplanes in France, Bleriot had been giving earnest attention to the production of a real "bird" machine, provided with one pair of FLAPPING wings. We know now that such an aeroplane is not likely to be of practical use, but with quiet persistence Bleriot kept to his task, and succeeded in evolving the famous Antoinette monoplane, which more closely resembles a bird than does any other form of air-craft.
In the illustration of the Bleriot monoplane here given you will notice that there is one main plane, consisting of a pair of highly-cambered wings; hence the name "MONOplane". At the rear of the machine there is a much smaller plane, which is slightly cambered; this is the elevating plane, and it can be tilted up or down in order to raise or lower the machine. Remember that the elevating plane of a biplane is to the front of the machine and in the monoplane at the rear. The small, upright plane G is the rudder, and is used for steering the machine to the right or left. The long narrow body or framework of the monoplaneis known as the FUSELAGE.
By a close study of the illustration, and the description which accompanies it, you will understand how the machine is driven. The main plane is twisted, or warped, when banking, much in the same way that the Wright biplane is warped.
Far greater speed can be obtained from the monoplane than from the biplane, chiefly because in the former machine there is much less resistance to the air. Both height and speed records stand to the credit of the monoplane.
The enormous difference in the speeds of monoplanes and biplanes can be best seen at a race meeting at some aerodrome. Thus at Hendon, when a speed handicap is in progress, the slow biplanes have a start of one or two laps over the rapid little monoplanes in a six-lap contest, and it is most amusing to see the latter dart under, or over, the more cumbersome biplane. Recently however, much faster biplanes have been built, and they bid fair to rival the swiftest monoplanes in speed.
There is, however, one serious drawback to the use of the monoplane: it is far more dangerous to the pilot than is the biplane. Most of the fatal accidents in aviation have been
caused through mishaps to monoplanes or their engines, and chiefly for this reason the biplane has to a large extent supplanted the monoplane in warfare. The biplane, too, is better adapted for observation work, which is, after all, the chief use of air-craft.
In a later chapter some account will be given of the three types of aeroplane which the war has evolved--the general-purposes machine, the single-seater "fighter", and those big bomb-droppers, the British Handley Page and the German Gotha.
CHAPTER XXIX
Henri Farman and the Voisin Biplane
The coming of the motor engine made events move rapidly in the world of aviation. About the year 1906 people's attention was drawn to France, where Santos Dumont was carrying out the wonderful experiments which we have already described. Then came Henri Farman, who piloted the famous biplane built by the Voisin brothers in 1907; an aeroplane destined to bring world-wide renown to its clever constructors and its equally clever and daring pilot.
There were notable points of distinction between the Voisin biplane and that built by the Wrights. The latter, as we have seen, had two propellers; the former only one. The launching skids of the Wright biplane gave place to wheels on Farman's machine. One great advantage, however, possessed by the early Wright biplane over its French rivals, was in its greater general
efficiency. The power of the engine was only about one-half of the power required in certain of the French designs. This was chiefly due to the use of the launching rail, for it needed much greater motor power to make a machine rise from the ground by its own motor engine than when it received a starting lift from a falling weight. Even in our modern aeroplanes less engine power is required to drive the craft through the air than to start from the ground.
Farman achieved great fame through his early flights, and, on 13th January, 1908, at the flying ground at Issy, in France, he won the prize of L2000, offered by MM. Deutsch and Archdeacon to the first aviator who flew a circular kilometre. In July of the same year he won another substantial prize given by a French engineer, M. Armengaud, to the first pilot who remained aloft for a quarter of an hour.
Probably an even greater performance was the cross-country flight made by Farman about three months later. In the flight he passed over hills, valleys, rivers, villages, and woods on his journey from Chalons to Rheims, which he accomplished in twenty minutes.
In the early models of the Voisin machine there were fitted between the two main planes a number of vertical planes, as shown clearly in the illustration facing p. 160. It was thought that these planes would increase the stability of the machine, independent of the skill of the operator, and in calm weather they were highly effective. Their great drawback, however, was that when a strong side wind caught them the machine was blown out of its course.
Subsequently Farman considerably modified the early-type Voisin biplane, as shown by the illustration facing p. 160. The vertical planes were dispensed with, and thus the idea of automatic stability was abandoned.
But an even greater distinction between the Farman biplane and that designed by the Wrights was in the adoption of a system of small movable planes, called AILERONS, fixed at extremities of the main planes, instead of the warping controls which we have already described. The ailerons, which are adapted to many of our modern aeroplanes, are really balancing flaps, actuated by a control lever at the right side of the pilot's seat, and the principle on which they are worked is very similar to that employed in the warp system of lateral stability.
CHAPTER XXX
A Famous British Inventor
About the time that M. Bleriot was developing his monoplane, and Santos Dumont was astonishing the world with his flying feats at Bagatelle, a young army officer was at work far away in a secluded part of the Scottish Highlands on the model of an aeroplane. This young man was Lieutenant J. W. Dunne, and his name has since been on everyone's lips wherever aviation is discussed. Much of Lieutenant Dunne's early experimental work was done on the Duke of Atholl's estate, and the story goes that such great secrecy was observed that "the tenants were enrolled as a sort of bodyguard to prevent unauthorized persons from entering". For some time the War Office helped the inventor with money, for the numerous tests and trials necessary in almost every invention before satisfactory results are achieved are very costly.
Probably the inventor did not make sufficiently rapid progress with his novel craft, for he lost the financial help and goodwill of the Government for a time; but he plodded on, and at length his plans were sufficiently advanced for him to carry on his work openly. It must be borne in mind that at the time Dunne first took up the study of aviation no one had flown in Europe, and he could therefore receive but little help from the results achieved by other pilots and constructors.
But in the autumn of 1913 Lieutenant Dunne's novel aeroplane was the talk of both Europe and America. Innumerable trials had been made in the remote flying ground at Eastchurch, Isle of Sheppey, and the machine became so far advanced that it made a cross-Channel flight from Eastchurch to Paris. It remained in France for some time, and Commander Felix, of the French Army, made many excellent flights in it. Unfortunately, however, when flying near Deauville, engine trouble compelled the officer to descend; but in making a landing in a very small field, not much larger than a tennis-court, several struts of the machine were damaged. It was at once seen that the aeroplane could not possibly be flown until it had been repaired and thoroughly overhauled. To do this would take several days, especially as there were no facilities for repairing the craft near by, and to prevent anyone from making a careful examination of the aeroplane, and so discovering the secret features which had been so jealously guarded, the machine was smashed up after the engine had been removed.
At that time this was the only Dunne aeroplane in existence, but of course the plans were in the possession of the inventor, and it was an easy task to make a second machine from the same model. Two more machines were put in hand at Hendon, and a third at Eastchurch.
On 18th October, 1913, the Dunne aeroplane made its first public appearance at Hendon, in the London aerodrome, piloted by Commander Felix. The most striking distinction between this and other biplanes is that its wings or planes, instead of reaching from side to side of the engine, stretch back in the form of the letter V, with the point of the V to the front. These wings extend so far to the rear that there is no need of a tail to the machine, and the elevating plane in front can also be dispensed with.
This curious and unique design in aeroplane construction was decided upon by Lieutenant Dunne after a prolonged observation at close quarters of different birds in flight, and the inventor claims for his aeroplane that it is practically uncapsizable. Perhaps, however, this is too much to claim for any heavier-than-air machine; but at all events the new design certainly appears to give greater stability, and it is to be hoped that by this and other devices the progress of aviation will not in the future be so deeply tinged with tragedy.
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