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Aviation History
1909
1909 - 0096.PDF
-FEBRUARY 13, 1909. altering the position of his centre of gravity by movements of his body. But one day he was upset by a side gust and was killed. Pilcher, in England, took up his epoch-making work. With his soaring machines he made some hundred glides, but he also made one too many. One day, in 1899, in attempting to soar from level ground by being towed by horses, his machine broke, and he fell to the ground. He died shortly afterwards, and became a British martyr of the air. It is sad to relate these successive tragedies, but recent accomplishment has fully justified the actions of those who gave their lives for the sake of knowledge and progress. The experiments of Mr. Octave Chanute, from 1896-1902, form important links in experimental flight. He first introduced the vital principle of making surfaces movable instead of the aviator, and he made use of superposed surfaces. Mr. Chanute had made an exhaustive study of the subject of aerial navigation, evidenced in his book '"Progress in Flying Machines." He estimated aright the value of the researches of Wenham, whose original memoir on superposed surfaces he has described as " classical." He did not hesitate to adopt the principles advocated by Wenham in his own practical machines. He thus afforded an example of the expediency of studying the past as well as the present. As the earth contains hidden treasures unexcavated for centuries, but which from their intrinsic beauty eclipse the decadent specimens of modern handi- craft, so, too, the annals of science contain hidden treasures— indispensable principles, which after years of oblivion have to be unearthed into the light of day. In his multiple-winged machine Mr. Chanute fixed the wings on pivots. They retro-acted and swung horizontally so as to bring the centre of pressure to coincide with a vertical line passing through the centre of gravity. After making 300 glides with this he made a double-decked machine. It consisted of a rectangular bridge truss of wood, braced by steel wires, and carrying aerocurve surfaces arched j^th on the top and bottom booms. An important feature was the rudder in the rear ; it was attached to the machine by an elastic arrangement. The upper and lower surfaces of this rudder were acted upon by the wind gusts, and altered the angle of incidence of the main supporting surfaces. Seven hundred glides were made by Mr. Chanute's assistants with this machine without any accident. In 1902 Mr Chanute devised a triple-decked machine, and in this the surfaces were pivoted to rock, fore and aft, on a stationary pivot. The work of Mr. Chanute represents important stages in the evolution of the flying machine, but it was reserved to two other geniuses to bring human flight to a point of progress where the prejudicial critic would be for ever silenced. These two geniuses were the Brothers Wright. I will, therefore, speak of their work, beginning with their earliest experiments. Before essaying practical flight, the Brothers Wright carried out laboratory experiments. It was in 1900 that they 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, 173 metres apart, each being 67 metres from tip to tip, 2"i3 metres wide, and arched I-I9th. 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 pre- liminary gliding experiments has depended, but also their recent ones with their motor-driven aeroplanes. 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 well be over-estimated. We have only to look to nature for its raison d'etre. An instantaneous photograph of a flight of seagulls shows how varied are the flexings of Nature's aeroplanes in their wondrous manoeuvrings to maintain and recover equilibrium. In the earliest machines of the Brothers Wright the flexing was attained by light strings held in the hands of the operator. In their recent machines a lever controls this as other accessory movements. The frame of the 1901 machine was of spruce wood and steel. With this machine about 100 glides were made from sand mounds, known as the Kill Devil Hills, at angles of 9 degrees to 10 degrees. A feature of those early experiments was the placing of the operator prone upon the gliding machine instead of in an upright position, to secure greater sa'ety 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 navi- gator and his companion are comfortably seated. After the experi- ments 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. Thus they showed they had attained to the use of surfaces of twice the area that previous experimenters had dared to handle. An insight into the cautious and scientific methods by which the Wrights have reached their ultimate success is afforded by the tests- which this new machine underwent before gliding flight was under- taken with it. 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 7 degrees. This was the slope of a hill over which the current was flowing. An experiment showed . that the machine would soar under these circumstances whenever the wind was of sufficient force to keep the angle of incidence : between 4 and 8 degrees. Hundreds of successful glides were after- wards made along the full length of this slope, the longest being: 22^ feet and the time 26 sees. Glides were made at angles of \ descent of 6 degrees to 7 degrees, and the glider supported 66 kilogs. per horse-power. The next step was to apply a motor and screw propellers in place of gravity. This was done in 1903, when four flights were made, the first lasting 12 sees., the last 59 sees., when 260 metres were covered at a height of 2 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 24J miles in half an hour at a speed of 38 miles an hour. Much more than this at the time the brothers would not say, and for three years the world thirsted for the fuller knowledge only this year revealed. 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. This summer at Le Mans, in France, and Fort Myers, in America, Mr. Wilbur Wright and Mr. Orville Wright have demonstrated to the world the veracity of their former statements. At Le Mans, Mr. Wilbur Wright won the world's record of flight—ih. 31m. 25fs. This event wasonly twodays- after the news had arrived of the accident to his brother's machine ' in America in which Mr. Orville Wright broke his leg and Lieut. Selfridge was killed. This accident, of necessity, caused a tem- porary depression. I can myself bear witness as to its momentary depressive effect on an illustrious aeronautical assemblage. Had there not been the brother at Le Mans to vindicate the good character of the Wright machine, the disaster might have been, another of those blows which retard progress. The accomplishment of Mr. Wilbur Wright's great feat at a time when his nerves must have received a severe shock was an example of the competency of the two geniuses who, of all aviators, have most forwarded aerial navigation. In Wilbur Wright's machine at Le Mans, the two superposed slightly concave surfaces are about 12*50 metres long and 2 metres wide. They are separated by a distance of i"8o metres. At a distance of 3 metres from the main supporting surfaces is the horizontal rudder for controlling the vertical motions. This is com- posed of two oval superposed planes. At 2 "50 metres in front of the main supporting surfaces is the vertical rudder, composed of two vertical planes. The 25-h.p. motor is placed on the lower aero-surface. This- weighs 90 kilogs. There is no carburettor, the petrol being injected into airlet pipes. At the left of this motor are the two seats, side by side, for the operator and his companion. The transmission of power to the two propeller-shafts is effected by chains running in guide tubes. The left-hand chain is crossed, ~ to give the opposite movement to the propellers. The two wooden propellers at the back of the machine are 2-50 metres in diameter. They have a low rate of revolution—450 revolutions per minute. Perhaps the weakest part of the Wright machine is the material of the propellers—this is wood. To this fact would appear to be due the fatal accident to Mr. Orville Wright's machine in America. As - is well known, Mr. Orville Wright had extended the length of those" propellers. In rotating, one of them struck against a wire, hanging loosely, and was bioken. Had the propeller been made of suitable metal, it would not, probably, have been broken by the impact. (7o be concluded.) ® ® ® ® Aeronautical Patents. Applied for In 1908. Published February iStk, 1909. 1,683. O. HKBREN. Aeroplanes
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