鈥?. That in arched surfaces the centre of pressure at 90 degrees is near the centre of the surface, but moves slowly forward as the angle becomes less, till a critical angle varying with the shape and depth of the curve is reached, after which it moves rapidly toward the rear till the angle of no lift is found. The Gordon-Bennett race of September, 1913, was again won by a Deperdussin machine, somewhat302 similar to that of the previous year, but with exceedingly small wings, only 107 square feet in area. The shape of these wings was instructive as showing how what, from the general utility point of view, may be disadvantageous can, for a special purpose, be turned to account. With a span of 21 feet, the chord was 5 feet, giving the inefficient 鈥榓spect ratio鈥?of slightly over 4 to 1 only. The object of this was to reduce the lift, and therefore the resistance, to as low a point as possible. The total weight was 1,500 lbs., giving a wing-loading of 14 lbs. per square foot鈥攁 hitherto undreamt-of figure. The result was that the machine took an enormously long run before starting; and after touching the ground on landing ran for nearly a mile before stopping; but she beat all records by attaining a speed of 126 miles per hour. Where this performance is mainly interesting is in contrast to the machines of 1920, which with an even higher speed capacity would yet be able to land at not more than 40 or 50 miles per hour, and would be thoroughly efficient flying machines. A great deal of sensation now appeared in the court-room, and most of the jury are said to have wept. They retired for a few moments, and returned a verdict for three years imprisonment in the penitentiary. On September 12th, 1908, Orville Wright, flying at Fort Meyer, U.S.A., with Lieut. Selfridge as passenger, crashed his machine, suffering severe injuries, while Selfridge was killed. This was the first aeroplane fatality. On October 30th, 1908, Farman made the first cross-country flight, covering the distance of 17 miles between Bouy and Rheims. The next day, Louis Bleriot, in flying from Toury to Artenay, made two landings en route, this being the first cross-country flight with landings. On the last day of the year, Wilbur Wright won the Michelin Cup at Auvours with a flight of 90 miles, which, lasting 2 hours 20 minutes 23 seconds, exceeded 2 hours in the air for the first time. 鈥業n 1892 a canal was being cut, close to where Lilienthal lived, in the suburbs of Berlin, and with the surplus earth Lilienthal had a special hill thrown up to fly from. The country round is as flat as the sea, and there is not a house or tree near it to make the wind unsteady, so this was an ideal practising ground; for practising on natural hills is generally rendered very difficult by shifty and gusty winds.... This98 hill is 50 feet high, and conical. Inside the hill there is a cave for the machines to be kept in.... When Lilienthal made a good flight he used to land 300 feet from the centre of the hill, having come down at an angle of 1 in 6; but his best flights have been at an angle of about 1 in 10. It is not yet twenty years since man first flew, but into that twenty years have been compressed a century or so of progress, while, in the two decades that preceded it, was compressed still more. We have only to recall and recount the work of four men: Lilienthal, Langley, Pilcher, and Clement Ader to see the immense stride that was made between the time when Penaud pulled a trigger for the last time and the Wright Brothers first left the earth. Into those two decades was compressed the investigation that meant knowledge of the qualities of the air, together with the development of the one prime mover that rendered flight a possibility鈥攖he internal combustion engine. The coming and progress of this latter is a thing apart, to be detailed separately; for the present we are concerned with the evolution of the driven plane, and with it the evolution of that daring being, the flying man. The two are inseparable, for the men gave themselves to their art; the story of Lilienthal鈥檚 life and death is the story of his work; the story of Pilcher鈥檚 work is that of his life and death. 2018日本一道高清国产_啵啵影院 To meet the demand for a smaller type of engine for use on training machines, the Rolls-Royce firm produced the 鈥楬awk鈥?Vee-type engine of 100 horse-power, and, intermediately between this and the 鈥楨agle,鈥?the 鈥楩alcon鈥?engine came to being with an original rated horse-power of 205 at 1,800 revolutions per minute, in April of 1916. Here was another case of growth of power in the same engine through research, almost similar to that of the 鈥楨agle鈥?type, for by July of 1918 the 鈥楩alcon鈥?was developing 285 horse-power with no radical alteration of design. Finally, in response to the constant demand for increase of power in a single plant, the Rolls-Royce company designed and produced the 鈥楥ondor鈥?type of engine, which yielded 600 horse-power on its first test in August of 1918. The cessation of hostilities and consequent falling off in the demand for extremely high-powered plants prevented the 鈥楥ondor鈥?being developed to its limit, as had been the 鈥楩alcon鈥?and 鈥楨agle鈥?types. The supporting surface of the wings was ample,141 and experiment showed the engine capable of supplying more than the necessary motive power. 355 鈥業ts best performances were two long trips performed during the summer of 1908. The first, on July 4th, lasted exactly 12 hours, during which time it covered a distance of 235 miles, crossing the mountains to Lucerne and Zurich, and returning to the balloon-house near Friedrichshafen, on Lake Constance. The average speed on this trip was 32 miles per hour. On August 4th, this airship attempted a 24-hour flight, which was one of the requirements made for its acceptance by the Government. It left Friedrichshafen in the morning with the intention of following the Rhine as far as Mainz, and then returning to its starting-point, straight across the country. A stop of 3 hours 30 minutes was made in the afternoon of the first day on the Rhine, to repair the engine. On the return, a second stop was found necessary near Stuttgart, due to difficulties with the motors, and some loss of gas. While anchored to the ground, a storm arose which broke loose the anchorage, and, as the balloon rose in the air, it exploded and took fire (due to causes which have never been actually determined and published) and fell to the ground, where it was completely destroyed. On this journey, which lasted in all 31 hours 15 minutes, the airship was in the air 20 hours 45 minutes, and covered a total distance of 378 miles.