CHAPTER V
THE BIRTH AND GROWTH OF THE AEROPLANE
It is to the honour of the British nation that one of the first principles of the biplane was proposed and explained by a British subject, Mr. F. H. Wenham, as far back as 1866. He pointed out that the lifting power of a surface can be economically obtained by placing a number of smaller surfaces one above another. Indeed, flying-machines were built by Wenham on this principle, with appliances for the use of his own muscular power. He did not, however, accomplish actual flight, although valuable results were obtained as regards the driving power of superposed surfaces.
After various further experiments in the same direction, it fell to H. von Helmholtz to emphasize the improbability that man could drive a flying-machine by his own muscular power. A period of stagnation followed. But interest was revived later, and fresh efforts were made, varying in importance, down to the experiments of Sir Hiram Maxim and Professor Langley.
[Illustration: DISTINCTION MARKS USED BY THE BELLIGERENTS IN THE WAR.
1. British. 2. Marks on rudder of British machine. 3. French. 4. Marks on rudder of French machine. 5. Russian. 6. Italian. 7. German and Austrian. 8. Turkish.
The British marks consist of circles, having a red and blue circumference, with a white or (occasionally) the natural colour of the fabric in between. The positions for these circles are:—Two on the upper surface of the top plane near the wing tips; two on the lower surface of the bottom plane, also close to the tips; one on each side of the body between the pilot’s seat and the tail. Sometimes simply a red circle is used on naval machines. The rudder is painted with three vertical stripes in the following order counting from front to back: blue, white, red. The French distinction marks are similar to the British, with the exception that the centre of the circles is blue and the circumference red. The Belgian, Serbian, and Roumanian marks are similar to the French. The Russian marks are lateral stripes on the planes in the order from the leading to the trailing edge of the wing: white, blue, red. Our Italian Allies incorporate their national colours in a rosette on their machines. The device has a red centre, then a white ring with a green circle outside.]
These two eminent men, who took up the subject of flying in the last decade of the last century, came to their task with great scientific knowledge. Hitherto flying was associated in the minds of the public with failure and folly. Indeed, Sir Hiram Maxim once remarked that at the time he took up the subject it was almost considered a disgrace to any one to think of it. It was thought ‘quite out of the practical question.’ But the two great men now in mind were not to be turned aside by ridicule. ‘They rescued aeronautics from a fallen position, and fired in its cause the enthusiasm of men of light and learning.’
Sir Hiram Maxim’s experiments were on a large scale. He built the largest flying-machine that had then been constructed. It had 4,000 feet of supporting surface and weighed 8,000 lbs.; the screw propellers measured 17 feet 11 inches in diameter, the width of the blade at the tip being 5 feet. The boiler was of 363 h.-p. This remarkable machine had wheels and a railway line, and was restrained from premature flight by a system of wooden rails. But it proved unruly. It burst through the wooden rails, and flew in a wholly unexpected fashion for 300 feet!
Professor Langley’s experiments carried flying still further. In 1896 he built a machine that flew for more than three-quarters of a mile. In this machine there was only 70 square feet of supporting surface, and the weight was only 72 lbs. It had a 1 h.-p. engine, weighing 7 lbs.
But Professor Langley had still to build a machine that would carry a man. This he did in due course, but when the machine was being put to the test over water, and at the very moment of being launched, it caught in the launching ways and was pulled into the water. Progress had, however, been made, and it is well worthy of note that of recent date an American aviator has unearthed Langley’s machine and flown on it, thus giving posthumous honour to the inventor.
Following the professor’s efforts, further progress was made by Mr. Octava Chanute, who introduced the important principle of making moveable surfaces. He also made use of superposed surfaces. But it was reserved for the two famous aviators, the brothers Wright, to bring the desired conquest of the air to a definite point.
Their first practical experiment was with gliding machines at Kitty Hawk, North Carolina, in 1900. They endeavoured with comparatively small surfaces to raise their machines like a kite by the wind. But they found that the wind was not always in their favour and often blew too strongly for their method. Consequently, they abandoned the idea, and resorted to flight by gliding. Their machines now had two superposed surfaces. They also introduced two highly important principles, namely, a horizontal rudder in front for controlling the vertical movements, and the principle of warping or flexing one wing or the other for steering purposes. Later a vertical rudder was added.
Writing of these improvements, Mr. Eric Stuart Bruce, Vice-President of the Aerial League of the British Empire, remarks that their importance cannot be over-estimated: ‘We have only to look at nature for their _raison d’être_, and observe the flight of seagulls over the sea. How varied are the flexings of nature’s aeroplanes in their wonderful manœuvrings to maintain and recover equilibrium!’
A feature of these early experiments was the placing of the operator prone upon the gliding machine, instead of in an upright position, to secure greater safety in alighting and to diminish the resistance. This, however, was only a temporary expedient while the Wrights were feeling their way. In the motor-driven aeroplanes the navigator and his companion were comfortably seated. After the experiment of 1901, the Wrights carried on laboratory researches to determine the amount and direction of the pressure produced by wind upon planes and arched surfaces exposed at various angles of incidence. They discovered that the tables of the air pressures which had been in use were incorrect.
As the result of these experiments the Wrights produced in 1902 a new and larger machine. This had 28·44 square metres of sustaining surfaces, about twice the area of previous experiments. At first the machine was flown in the manner of a kite, with the view of learning whether it would soar in a wind. Experiments showed that the machine soared whenever the wind was of sufficient force to keep the angle of incidence between four and eight degrees. Later, in 1903, screw propellers were applied and four flights made. Definite progress favoured the venture. Two hundred and sixty metres were covered at a height of two metres!
In the following year, 1904, there was further marked progress, many successful flights, some ‘circular,’ being made. In the next year came an astonishing achievement: the Wrights flew no less than 24¼ miles in half an hour. This was rightly deemed at the time a great flight forward. But a period of silence and seeming inactivity followed. It was not until 1908 that further revelations were made. It was then seen that the Wrights had not been idle. Indeed, it is said (and with obvious justice) that ‘to the labours of the Wright brothers we owe the advent of the mobile and truly efficient military air scout.’