The brothers Wright first carried out laboratory experiments; they then, in 1900, first began to experiment with gliding machines at Kitty Hawk, North Carolina. With the comparatively small surfaces (15.3 square metres) they used in that year, they endeavoured to raise the machine by the wind like a kite; but finding that it often blew too strongly for such a system to be practical, in 1901 they abandoned the idea and resorted to gliding flight.
These machines of 1901 had two superposed surfaces, 1.73 metres apart, each being 6.7 metres from tip to tip, 2.13 metres wide, and arched 1-19th. The total supporting surface was 27 square metres. They dispensed with the tail which previous experimenters had considered necessary. Instead, they introduced into their machine two vital principles, upon which not only the success of their preliminary gliding experiments depended, but also their later ones with their motor-driven aëroplanes—(1) the hinged horizontal rudder in front for controlling the vertical movements of the machine; (2) the warping or flexing of one wing or the other for steering to right or left.
Later, a vertical rudder was also added for horizontal steering. The combined movements of these devices maintained equilibrium. The importance of the system of torsion of the main carrying surfaces cannot be overestimated. We have only to look to nature for its raison d’être, and observe a flight of seagulls over the sea: how varied are the flexings of nature’s aëroplanes in their wondrous manœuvrings to maintain and recover equilibrium! Since the appearance of the Wright motor-driven aëroplane, the principle of moving either the main surface or attachments to the main surface has been very generally adopted in other types of flying machines. 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 aëroplanes the navigator and his companion were comfortably seated. After the experiments of 1901, the Wrights carried on laboratory researches to determine the amount and direction of the pressures produced by the 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. Upon the results of these experiments they produced, in 1902, a new and larger machine. This had 28.44 square metres of sustaining surfaces—about twice the area that previous experimenters had dared to handle. The machine was first flown as a kite, so that it might be ascertained whether it would soar in a wind having an upward trend of a trifle over seven degrees; and this trend was found on the slope of a hill over which the current was flowing. Experiment showed that the machine soared under these circumstances whenever the wind was of sufficient force to keep the angle of incidence between four and eight degrees. Hundreds of successful glides were made along the full length of this slope, the longest being 22½ feet, and the time 26 seconds. A motor and screw propellers were then applied in place of gravity, in 1903, and four flights made, the first lasting 12 seconds, and the last 59 seconds, when 260 metres were covered at a height of two metres.
In 1904, several hundred flights were made, some being circular. All this work was carried on in a secluded spot and unpublished. In December, 1905, the world was startled by the news that the brothers Wright had flown for 24¼ miles in half an hour, at a speed of 38 miles an hour. More than this at the time the brothers would not say, and for three years the world thirsted for the fuller knowledge only revealed in 1908. In the interval some went so far as to distrust the statements of the brothers Wright; but those who, like myself, had had the privilege of correspondence with them from their first experiments felt the fullest confidence that every statement they had made was fact.
I have somewhat dwelt on the preliminary experiments of the brothers Wright with their gliding structures as indicating the rapidity of progress attained when sound scientific method is combined with practical experiment. Too often in the past there has been a tendency amongst the workers in science to keep theory and practice apart. They are, however, interdependent. Each has a corrective influence on the other.
To the labours of the Wright brothers we certainly owe the advent of the mobile and truly efficient military air scout. It is their efforts that have revolutionised warfare. In the present war we see only the beginnings of what will one day be; but they are none the less truly prophetic.
It was the enthusiastic Captain Ferber, who later became a victim to his ardour for aërial achievement, who realised what the brothers Wright had accomplished for military aëronautics. The latter having entered into communications with the French Government respecting the sale of their machines, Captain Ferber was deputed by the French Government to go to America and report on their claims. As the brothers Wright at that time so carefully guarded the secrecy of their details, he was not allowed to see the machine when he arrived, and had to be content with the mere hearsay of certain persons at Ohio, who had witnessed their flights. But he had sufficient faith in the brothers Wright to recommend the French Government to buy their invention.
The negotiations, however, fell through at the time, but in 1908 Wilbur Wright came to France to carry on experiments at Le Mans, while his brother, Mr. Orville Wright, went to Fort Myers in America.
In Wilbur Wright’s machine at Le Mans, the two superposed slightly concave surfaces were about 12.50 metres long and 2 metres wide. They were separated by a distance of 1.80 metres. At a distance of 3 metres from the main supporting surfaces was the horizontal rudder for controlling the vertical motions; this was composed of two oval superposed planes. At 2.50 metres in front of the main supporting surfaces was the vertical rudder, composed of two vertical planes.
The 25 h.p. motor was placed on the lower aëro-surface; this weighed ninety kilogrammes. At the left of the motor were the two seats, side by side, for the aëronaut and his companion. The two wooden propellers at the back of the machine were 2.50 metres in diameter. They revolved at the rate of 450 revolutions per minute.