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时间: 2019年12月13日 15:08

In this work is no claim to originality鈥攊t has been a matter mainly of compilation, and some stories, notably those of the Wright Brothers and of Santos Dumont, are better told in the words of the men themselves than any third party could tell them. The author claims, however, that this is the first attempt at recording the facts of development and stating, as fully as is possible in the compass of a single volume, how flight and aerostation have evolved. The time for a critical history of the subject is not yet. Russia spent vast sums in the provision of machines: the giant Sikorsky biplane, carrying four 100 horse-power Argus motors, was designed by a young Russian engineer in the latter part of 1913, and in its early trials it created a world鈥檚 record by carrying seven passengers for 1 hour 54 minutes. Sikorsky also designed several smaller machines, tractor biplanes on the lines of the British B.E. type, which were very successful. These were the only home productions, and the imports consisted mainly of French aeroplanes by the hundred, which got as far as the docks and railway sidings and stayed there, while German influence and the corruption that ruined the Russian Army helped to lose the War. A few Russian aircraft factories were got into operation as hostilities proceeded, but their products were negligible, and it is not on record that Russia ever learned to manufacture a magneto. � Practically all glides gave the same result, and in one the machine rose higher and higher until it lost all headway. 鈥楾his was the position from which Lilienthal had always found difficulty in extricating himself, as his machine then, in spite of his greatest exertions, manifested a tendency to dive downward almost vertically and strike the ground head on with frightful velocity. In this case a warning cry from the ground caused the operator to turn the rudder to its full extent and also to move his body slightly forward. The machine then settled slowly to the ground, maintaining its horizontal position almost perfectly, and landed without any injury at all. This was very encouraging, as it showed that one of the very greatest dangers in machines with horizontal tails had been overcome by the use of the front rudder. Several glides later the same experience was repeated with the same result. In the latter case156 the machine had even commenced to move backward, but was nevertheless brought safely to the ground in a horizontal position. On the whole this day鈥檚 experiments were encouraging, for while the action of the rudder did not seem at all like that of our 1900 machine, yet we had escaped without difficulty from positions which had proved very dangerous to preceding experimenters, and after less than one minute鈥檚 actual practice had made a glide of more than 300 feet, at an angle of descent of ten degrees, and with a machine nearly twice as large as had previously been considered safe. The trouble with its control, which has been mentioned, we believed could be corrected when we should have located its cause.鈥? Tell him to come at half-past ten, returned Castalia. Deary me, ma'am! cried simple Mrs. Thimbleby, with ready sympathy, looking into her lodger's round comely face. "Nothing wrong with Mr. Algernon, I hope?" 日本无码不卡高清免费v 日本无码不卡高清免费av在线中文字幕不卡手在线观看 It may be said that Louis Bleriot was responsible for the second great landmark in the history of successful flight. The day when the brothers Wright succeeded in accomplishing power-driven flight ranks as the first of these landmarks. Ader may or may not have left the ground, but the wreckage of his 鈥楢vion鈥?at the end of his experiment places his doubtful success in a different category from that of the brothers Wright and leaves them the first definite conquerors, just as Bleriot ranks as first definite conqueror of the English Channel by air. Their first balloon, made of paper, reverted to the hot-air principle; they lighted a fire of wool and wet straw under the balloon鈥攁nd as a matter of course the balloon took fire after very little experiment; thereupon they constructed a second, having a capacity of 700 cubic feet, and this rose to a height of over 1,000 feet. Such a success gave them confidence, and they gave their first public exhibition on June 5th, 1783, with a balloon constructed of paper and of a circumference of 112 feet. A fire was lighted under this balloon, which, after rising to a height of 1,000 feet, descended through the cooling of the air inside a matter of ten minutes. At this the Acad茅mie des Sciences invited the brothers to conduct experiments in Paris. Who could tell how it got abroad in the town that young Mrs. Errington was in the habit of following her husband about; of watching him, spying on his actions, and examining his private correspondence? Mr. Obadiah Gibbs, who could have told more than any one on the latter head, was not given to talking. Yet the fact oozed out. They say you are an honest, decent man, Castalia went on, neither seating herself nor noticing the invitation to do so. "It may be so. I am willing to believe it. But, if so, you are grossly deceived, cheated, and played upon by that vile girl." Cape to Cairo.