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时间: 2019年12月11日 19:23

� Contemporary with him was Charles Spencer, the first man to practise gliding in England. His apparatus consisted of a pair of wings with a total area of 30 sq. ft., to which a tail and body were attached. The weight of this apparatus was some 24 lbs., and, launching himself on it from a small eminence, as was done later by Lilienthal in his experiments, the inventor made flights of over 120 feet. The glider in question was exhibited at the Aeronautical Exhibition of 1868. The appearance of the machine prepared for flight was exceedingly light and graceful, giving an impression to all observers of being capable of successful flight. � � � 黄色的小影院,黄色的视频网站,免费观看特别黄大片-优衣库视频 Very intelligent on the part of the official, Mr. Wing! Only I think you and I had come to pretty nearly the same conclusion before. FREDERICK IN THE GARDEN. Cross Section, Manly鈥檚 5 Cylinder Radial Engine. � Chanute realised that experiments with models were of little use; in order to be fully instructive, these experiments should be made with a full-sized machine which carried its operator, for models seldom fly twice alike in the open air, and no relation can be gained from them of the divergent air currents which they have experienced. Chanute鈥檚 idea was that any flying machine which might be constructed must be able to operate in a wind; hence the necessity for an operator to report upon what occurred in flight, and to acquire practical experience of the work of the human factor in imitation of bird flight. From this point of view he conducted his own experiments; it must be noted that he was over sixty years of age when he began, and, being no longer sufficiently young and active to perform any but short and insignificant glides, the courage of the man becomes all the more noteworthy; he set to work to evolve the state required by the problem of stability, and without any expectation of advancing to the construction of a flying machine which might be of commercial value. His main idea was the testing of devices to secure equilibrium; for this purpose he employed assistants to carry out the practical work, where he himself was unable to supply the necessary physical energy.