鈥楾he first boiler which I made was constructed something on the Herreshof principle, but instead of having one simple pipe in one very long coil, I used a series of very small and light pipes, connected in such a manner that there was a rapid circulation through the whole鈥攖he tubes increasing in size and number as the steam was generated. I intended that there should be a pressure of about 100 lbs. more on the feed-water end of the series than on the steam end, and I believed that this difference in pressure would be sufficient to ensure a direct and positive circulation through every tube in387 the series. The first boiler was exceedingly light, but the workmanship, as far as putting the tubes together was concerned, was very bad, and it was found impossible to so adjust the supply of water as to make dry steam without overheating and destroying the tubes. Follows Professor John J. Montgomery, who, in the true American spirit, describes his own experiments so well that nobody can possibly do it better. His account of his work was given first of all in the American Journal, Aeronautics, in January, 1909, and thence transcribed in the English paper of the same name in May, 1910, and that account is here copied word for word. It may, however, be noted first that as far back as 1860, when Montgomery was only a boy, he was attracted to the study of aeronautical problems, and in 1883 he built his first machine, which was of116 the flapping-wing ornithopter type, and which showed its designer, with only one experiment, that he must design some other form of machine if he wished to attain to a successful flight. Chanute details how, in 1884 and 1885, Montgomery built three gliders, demonstrating the value of curved surfaces. With the first of these gliders Montgomery copied the wing of a seagull; with the second he proved that a flat surface was virtually useless, and with the third he pivoted his wings as in the Antoinette type of power-propelled aeroplane, proving to his own satisfaction that success lay in this direction. His own account of the gliding flights carried out under his direction is here set forth, being the best description of his work that can be obtained:鈥? Next to this was 鈥楢rmy Airship 2A鈥?launched early in 1910 and larger, longer, and narrower in design than the Baby. The engine was an 80 horse-power Green motor which drove two pairs of propellers; small inflated control members were fitted at the stern end of the envelope, which was 154 feet in length. The suspended car was 84 feet long, carrying both engines and crew, and the Willows idea of swivelling propellers for governing the direction was used in this vessel. In June of that year a new, small-type dirigible, the 鈥楤eta,鈥?was produced, driven by a 30 horse-power Green engine with which she flew over 3,000 miles. She was the most successful British dirigible constructed up to that time, and her successor, the 鈥楪amma,鈥?was built on similar lines. The 鈥楪amma鈥?was a larger vessel, however, produced in 1912, with flat, controlling fins and rudder at the rear end of the envelope, and with the conventional long car suspended at some distance beneath the gas bag. By this time, the mooring mast, carrying a cap of which the concave side fitted over the convex nose of the airship, had been originated.362 The cap was swivelled, and, when attached to it, an airship was held nose on to the wind, thus reducing by more than half the dangers attendant on mooring dirigibles in the open. Old Max looked up at his visitor over the great tortoise-shell spectacles on his nose. He had a large Bible open on the table before him. The large Bible was placed there every evening, and on Sunday evenings any other mundane volume which might chance to be lying in the parlour was carefully removed out of sight, to be restored to the light of day on Monday morning. This was the custom of the house, and had been so for years. It had obtained all through the Methodist days, and now lasted under the new orthodox dispensation. Since old Max had his spectacles on, it was to be supposed that he had been reading, and, since there was no other printed document within sight, not even an almanac, it was clear that he could have been reading nothing but his Bible. And yet it was nearly an hour since he had turned the page before him. He had been dozing, sitting up in his chair by the fire. This had latterly become a habit with him whenever he was left alone in the evening. And once, even, he had fallen into a sleep, or a stupor, in the midst of the assembled family, and, on awaking, had been lethargic in his movements, and dazed in his manner for some time. 男人和女人做人爱视频,久天啪天天99久久,欧美一级特黄大片,大香蕉在线新观看视频 鈥業 dare say not,鈥?he said, still non-committally. Deary me, ma'am! cried simple Mrs. Thimbleby, with ready sympathy, looking into her lodger's round comely face. "Nothing wrong with Mr. Algernon, I hope?" Among the little group of French experimenters in these first years of practical flight, Santos-Dumont takes high rank. He built his 鈥楴o. 14 bis鈥?aeroplane in biplane form, with two superposed main plane surfaces, and fitted it with an eight-cylinder Antoinette motor driving a two-bladed aluminium propeller, of which the blades were 6 feet only from tip to tip. The total lift surface of 860 square feet was given with a wing-span of a little under 40 feet, and the weight of the complete machine was 353 lbs., of which the engine weighed 158 lbs. In July of 1906 Santos-Dumont flew a distance of a few yards in this machine, but damaged it in striking the ground; on October 23rd of the same year he made a flight of nearly 200 feet鈥攚hich might have been longer, but that he feared a crowd in front of the aeroplane and cut off his ignition. This may be regarded as the first effective flight in Europe, and by it Santos-Dumont takes his place as one of the chief鈥攊f not the chief鈥攐f the pioneers of the first years of practical flight, so far as Europe is concerned. 412 Developing from the Vee type, the eighteen-cylinder 475 brake horse-power engine, designed during the war, represented for a time the limit of power obtainable from a single plant. It was water-cooled throughout, and the ignition to each cylinder was duplicated; this engine proved fully efficient, and economical in fuel consumption. It was largely used for seaplane work, where reliability was fully as necessary as high power.