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日本视频网站www色

时间: 2019年12月06日 00:37

� The rosebuds that bloom on thy fat little cheek,鈥? That was the substance of the carpenter's story. The matter of experiment along any lines in connection with aviation is primarily one of hard cash. Throughout the whole history of flight up to the outbreak of the European war development has been handicapped on the score of finance, and, since the85 arrival of the aeroplane, both ornithopter and helicopter schools have been handicapped by this consideration. Thus serious study of the efficiency of wings in imitation of those of the living bird has not been carried to a point that might win success for this method of propulsion. Even Wilbur Wright studied this subject and propounded certain theories, while a later and possibly more scientific student, F. W. Lanchester, has also contributed empirical conclusions. Another and earlier student was Lawrence Hargrave, who made a wing-propelled model which achieved successful flight, and in 1885 was exhibited before the Royal Society of New South Wales. Hargrave called the principle on which his propeller worked that of a 鈥楾rochoided plane鈥? it was, in effect, similar to the feathering of an oar. Do you know, Lydia tells me the man was quite insolent! said Castalia. "What can be done with such people? They don't seem to me to have the least idea who we are!" Sophia. [Throwing herself into her arms.] O my Ratty! 日本视频网站www色 鈥楾he slope of the hill was 9.5 degrees, or a drop of one foot in six. We found that after attaining a speed of about twenty-five to thirty miles with reference to154 the wind, or ten to fifteen miles over the ground, the machine not only glided parallel to the slope of the hill, but greatly increased its speed, thus indicating its ability to glide on a somewhat less angle than 9.5 degrees, when we should feel it safe to rise higher from the surface. The control of the machine proved even better than we had dared to expect, responding quickly to the slightest motion of the rudder. With these glides our experiments for the year 1900 closed. Although the hours and hours of practice we had hoped to obtain finally dwindled down to about two minutes, we were very much pleased with the general results of the trip, for, setting out as we did with almost revolutionary theories on many points and an entirely untried form of machine, we considered it quite a point to be able to return without having our pet theories completely knocked on the head by the hard logic of experience, and our own brains dashed out in the bargain. Everything seemed to us to confirm the correctness of our original opinions: (1) That practice is the key to the secret of flying; (2) that it is practicable to assume the horizontal position; (3) that a smaller surface set at a negative angle in front of the main bearing surfaces, or wings, will largely counteract the effect of the fore and aft travel of the centre of pressure; (4) that steering up and down can be attained with a rudder without moving the position of the operator鈥檚 body; (5) that twisting the wings so as to present their ends to the wind at different angles is a more prompt and efficient way of maintaining lateral equilibrium than shifting the body of the operator.鈥? Having got off the earth, the very early balloonists set about the task of finding a means of navigating the air, but, lacking steam or other accessory power to human muscle, they failed to solve the problem. Joseph Mongolfier speedily exploded the idea of propelling a balloon either by means of oars or sails, pointing out that even in a dead calm a speed of five miles an hour would be the limit achieved. Still, sailing balloons were constructed, even up to the time of Andree, the explorer, who proposed to retard the speed of the balloon by ropes dragging on the ground, and then to spread a sail which should catch the wind and permit of deviation of the course. It has been proved that slight divergences from the course of the wind can be obtained by this means, but no real navigation of the air could be thus accomplished. The new Army aeroplane. What can you tell us of the death of this unfortunate lady, Mr. Powell? asked the coroner, quietly. "You were the first to see her struggling in the water, were you not? And you made a gallant effort to save her." Apart from the metallic construction of aeroplanes an enormous amount of work was done in the testing of different steels and light alloys for use in engines, and by the end of the War period a number of aircraft engines were in use of which the pistons and other parts were of such alloys; the chief difficulty having been not so much in the design as in the successful heat-treatment and casting of the metal.