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时间: 2019年12月13日 03:20

Rotation of the cylinders in engines of this type is produced by the side pressure of the pistons on the cylinder walls, and in order to prevent this pressure from becoming abnormally large it is necessary to keep the weight of the piston as low as possible, as the pressure is produced by the tangential acceleration and retardation of the piston. On the upward stroke the circumferential velocity of the piston is rapidly increased, which causes it to exert a considerable tangential pressure on the side of the cylinder, and on the return stroke there is a431 corresponding retarding effect due to the reduction of the circumferential velocity of the piston. These side pressures cause an appreciable increase in the temperatures of the cylinders and pistons, which makes it necessary to keep the power rating of the engines fairly low. � With this 200 horse-power Anzani, a petrol consumption of as low as 0鈥?9 lbs. of fuel per brake horse-power per hour has been obtained, but the consumption of lubricating oil is compensatingly high, being up to one-fifth of the fuel used. The cylinders are set desax茅 with the crank shaft, and are of cast-iron, provided with radiating ribs for air-cooling; they are attached to the crank case by long bolts passing through bosses at the top of the cylinders, and connected to other bolts at right angles through the crank case. The tops of the cylinders are formed flat, and seats for the inlet and exhaust valves are formed on them. The pistons are cast-iron, fitted with ordinary cast-iron spring rings. An aluminium crank case is used, being made in two halves connected together by bolts, which latter also attach the engine to the frame of the machine. The crankshaft is of nickel steel, made hollow, and mounted on ball-bearings in such a manner that practically a combination of ball and plain bearings is obtained; the central web of the shaft is bent to bring the centres of the crank pins as close together as possible, leaving only room for the connecting rods, and the pins are422 180 degrees apart. Nickel steel valves of the cone-seated, poppet type are fitted, the inlet valves being automatic, and those for the exhaust cam-operated by means of push-rods. With an engine having such a number of cylinders a very uniform rotation of the crankshaft is obtained, and in actual running there are always five of the cylinders giving impulses to the crankshaft at the same time. Young Ferdinand, who loved me! Horatia. A profound genius.... � 成年人网站_成人网站大全免费观看_成人综合网 A home was found in Charlotte Square, Edinburgh; and for some years, till 1819 or 1820, he was well content to remain there, living a quiet home-life, with a little family growing around him. Two more boys came, George William and Robert Tudor,鈥攖he former dying in babyhood, the latter growing up to be slain in the Indian Mutiny. Losing the infant George was a dire trouble to his parents; and Mrs. Tucker, believing that he had succumbed to the keen cold of Edinburgh, was never at rest in her mind until the northern home had been exchanged for one in the south. Such a change was not to be accomplished in a day, but in the course of time it came about; and meanwhile the remaining children were a constant source of interest and delight. The 鈥榖aby鈥?at this date was Robert; afterwards a very favourite elder brother of A. L. O. E. His children, known in the family by the name of 鈥楾he Robins,鈥?became in later years as her own. You will understand, said Gibbs, "that I am speaking to you in the very strictest confidence. I should be sorry for it to come out that I had meddled in the matter. Nor, sir, would it be well for you to have it known that I gave you any warning." � For dirigibles, balloons, and kite balloons the parachute is an essential. It would seem to be equally essential in the case of heavier-than-air machines, but this point is still debated. Certainly it affords the occupant of a falling aeroplane a chance, no matter how slender, of reaching the ground in safety, and, for that reason, it would seem to have a place in aviation as well as in aerostation. [The others kneel.]