时间: 2019年12月16日 18:24

Giffard, inventor of the steam injector, had already made balloon ascents when he turned to aeronautical propulsion, and constructed a steam engine of 5 horse-power with a weight of only 100 lbs.鈥攁 great achievement for his day. Having got his engine, he set about making the balloon which it was to drive; this he built with the aid of two other enthusiasts, diverging from335 Meusnier鈥檚 ideas by making the ends pointed, and keeping the body narrowed from Meusnier鈥檚 ellipse to a shape more resembling a rather fat cigar. The length was 144 feet, and the greatest diameter only 40 feet, while the capacity was 88,000 cubic feet. A net which covered the envelope of the balloon supported a spar, 66 feet in length, at the end of which a triangular sail was placed vertically to act as rudder. The car, slung 20 feet below the spar, carried the engine and propeller. Engine and boiler together weighed 350 lbs., and drove the 11 foot propeller at 110 revolutions per minute. Not at all! There is no difficulty in accounting for my distaste for the whole business. There can be no difficulty. It is the simplest, most obvious thing in the world! Sophia. [Aside to Barbara.] O Bab, such lying can never thrive. Meusnier鈥檚 balloon, of course, was never constructed, but his ideas have been of value to aerostation up to the present time. His career ended in the revolutionary army in 1793, when he was killed in the fighting before Mayence, and the King of Prussia ordered all firing to cease until Meusnier had been buried. No other genius came forward to carry on his work, and it was realised that human muscle could not drive a balloon with certainty through the air; experiment in this direction was abandoned for nearly sixty years, until in 1852 Giffard brought the first practicable power-driven dirigible to being. 鈥楢t first Lilienthal used to experiment by jumping off a springboard with a good run. Then he took to practising on some hills close to Berlin. In the summer of 1892 he built a flat-roofed hut on the summit of a hill, from the top of which he used to jump, trying, of course, to soar as far as possible before landing.... One of the great dangers with a soaring machine is losing forward speed, inclining the machine too much down in front, and coming down head first. Lilienthal was the first to introduce the system of handling a machine in the air merely by moving his weight about in the machine; he always rested only on his elbows or on his elbows and shoulders.... Where was I? Where must I be? Where am I every afternoon? At the office鈥攃onfound it! 99XXXX开心情色站_26UUU色五月_激情五月_开心五月天-开心色播网 It is no derogation of the work accomplished by the Wright Brothers to say that they won the honour of the first power-propelled flights in a heavier-than-air machine only by a short period. In Europe, and especially in France, independent experiment was being conducted by Ferber, by Santos-Dumont, and others, while in England Cody was not far behind the other giants of those days. The history of the early years of controlled power flights is a tangle of half-records; there were no chroniclers, only workers, and much of what was done goes unrecorded perforce, since it was not set down at the time. Powell! Yes, that was the name鈥擠avid Powell. V WENHAM, LE BRIS, AND SOME OTHERS Col. No, what of him? To recapitulate鈥攊n the course of these original experiments the Wrights confirmed Lilienthal鈥檚 theory of the reversal of the centre of pressure on cambered surfaces at small angles of incidence: they confirmed the importance of high aspect ratio in respect to lift: they had evolved new and more accurate tables of lift and pressure on cambered surfaces: they were the first to use a movable horizontal elevator for controlling height: they were the first to adjust the wings to different angles of incidence to maintain lateral balance: and they were the first to use the movable rudder and adjustable wings in combination.