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Aviation History
1915
1915 - 0219.PDF
MARCH 26, 1915. (70H3 Edited by V. E. Professor Langley's Model Work. (Continued from page 201.) " I PASS over a subsequent period of baffled effort with the slate- ment that numerous devices for launching were tried in vain, and that nearly a year passed before one was effected. Six trips and trials were made in the first six months of 1894 without securing a launch. On October 24th a new launching apparatus was tried for the first time, which embodied all the requisites whose necessity was taught by previous experience, and, saving occasional accidents, the launching was from this time forward accomplished with compara tively little difficulty. " The models were now, for the first time, launched fairly into the air, and a new class of difficulties arose, due to a cause which was at first obscure, for two successive launches of the same model, under conditions as near alike as possible, would be followed by entirely different results. For example, in the first case it might be found rushing, not falling, downward and forward into the water, under the combined impulse of the two engines ; in the second case, with every condition (apparently) the same, it might be found soaring upward until its wirgs made an angle of 6o° with the horizon, and unable to sustain itself at such an angle slide back into the water. " After a great deal of embarrassment the trouble was discovered to be due to the fact that the wings, though originally set at precisely the same angle in the two cases, were irregularly deflected by the upward pressure of the air, so that they no longer had the form which they appeared to possess the moment before they were upborn by it, and so that a very minute difference, too small to be noted with certainty, exaggerated by this pressure, might cau-e the wind of advance to strike either below or above the wing, and to produce the feature referred to. When this was noticed, all the models were inverted, and sand was dredged uniformly over the wings until the weight represented that of the machine. The flexure of the wings under these circumstances must be nearly that in free air, and it was found to distort them beyond all anticipation. Then commenced another series of trials, in which the wings were strengthened in various ways, but in none of them, without incurring a prohibitive weight, was it possible to make them strong enough. Various methods of guying them were tried, and they were rebuilt on different designs, a slow and expensive process. Finally, it may be said in anticipa tion (and largely through the skill of Mr. Reed, the foreman of the work) the wings were rendered strong enough without excessive weight, but a year or more passed in these and other experiments. " In the latter part of 1894 two steel models had already been built, which sustained from 40 to 50 per cent, of their dead-lift weight on the pendulum, and each of which was apparently supplied with much more than sufficient power for horizontal flight (the engine and all the moving parts furnishing over one horse power at the brake in one of the models, weighed but 26 ozs., but it may be remarked that the boilers and engines in lifting this per cent, of the weight did so only under favourable conditions on a bench test, and that nothing like this could be counted upon for regular performance in the open. Every experiment with the launching apparatus, when the model descended into the water, not gently but imperilled by the misdirected power of its own engines, resulted at this stage in severe strains and local injury, so that repairing, which was almost rebuilding, constantly went on—a hard but necessary condition attendant on the necessity of trial in the open air. It was gradually found that it was indispensable to make the frame stronger than had hitherto been done, although the absolute limit of strength consistent with weight seemed to have been already reached, and the year 1895 was chiefly devoted to the labour on the wings, and what seemed at first the hopeless task of improving the construction so that it might be stronger without additional weight when every gramme of weight had already been scrupulously economised. With this went on attempts to carry the effective power of the burners, boilers and engines further, and modification of the internal arrangement and a general disposition of the parts such that the wings could be placed further forward or backward at pleasure to more readily meet the conditions for bringing the centre of gravity under the centre of pressure. So little even now had been learned about the system of balancing in the open air, that at this late day recourse was had to rubber models, of a different character, how- JOHNSON,,M.A. ever, from those previously used ; for in the latter the rubber was strained, not twisted [Aeromodellists should note this point; several very ingenious modes of doing this have been published in FUOB 1. one quite recently]. These experiments took up an inordinate time, though the flight obtained from the rubber motors thus made was somewhat longer and much steadier than that obtained with the Penaud form, and fiom them a good deal of valuable informa tion was gained as to the number and position of the wings and as to the effectiveness of different forms and dispositions of them." (To be continued.) The Possibilities of an Aerial Torpedo Controlled by Wireless. The Sphere of March 13th, under the above title, publishes a two-page article (profusely illustrated) by a correspondent, and some notes relating to the same, by its aviation expert. The communication appears to have been prompted by some successful experiments in which a small dirigible was successfully steered and maim-uvred within the confines of an ordinary music hall by a wireless operator on the stage, and the successful trials of the American radio-controlled torpedo boat, " Natalia," the inven tion of Dr. John Hays Hammond, jun. This latter pilotless craft is designed to travel over the water's surface by wireless control only, her motors and steering gear being controlled by wireless controlled from the shore. A load of explosives totalling 4,000 lbs. can be carried by this novel weapon of attack. The idea of controlling a boat by wireless is no new thing ; it was first worked out, we believe, by Nikola Tesla. We have, too, the electrically contiolled torpedo of Armstrong and Orling, and others that we could name Last year, long before the war, the writer strongly urged some of the most advanced aeromodellisls to consider the question of the wireles? control of model aeroplanes. Leaving out altogether the idea of carrying anything in the nature of an explosion chamber and explosive, the question is one of a very formidable nature indeed. The correspondent in the Sphere says that the span could be quite small, with a wing span of about 10 ft. ; the illustrations show a monoplane, too, at that. With this spanned machine it is proposed to carry, in addition to a petrol engine and accessories, an explosion chamber, and, of course, explosives, a wireless control containing switches operating the various levers, wireless aerials, engine throttle control rod, rudder controls, and elevator plane control rods. The model is to be stabilised on the "Dunne" or some similar principle. The aerial torpedo would be controlled by an observer seated in an aeroplane, who would steer it in any direction and remain in safety himself. At night-time it would be operated by covering the wings with phosphorescent paint. In conclusion, the correspondent says: " Having given a rough idea of the design and possibilities of this weapon, I leave it to our engineering experts to decide whether such a machine is within the realms of possibility." The aviation expert of the Sphere in his remarks says : " Although the machine illustrated is of a type that could scarcely be used suc cessfully as suggested, the idea is certainly feasible, and will, no doubt, in later years be so perfected that it will prove a menace to the large aeroplanes that will come into being. . . . It is highly probable that the first flying torpedoes . . . (to) attain any practical success will, in a way, follow the form of the ' flying sticks ' of the aeromodellists of to-day. They will be high-powered for their size, and driven by a small petrol engine driving twin propellers at the rear ; the planes will be so constructed that they will have automatic stability [They have this already], and will carry a small wireless receiver to catch the waves sent out from the controller below, who will thus be enabled to guide them to their mark. In the nose of the machine will be placed the explosive, which will burst on contact. These miniature machines will have to be so constructed so as to have a good gliding angle so that should the engine fail the operator can bring them down in a spot where the explosion of their bomb will do no harm. The wireless apparatus would be carefully tuned. At present the science of aviation is not advanced far enough for us to construct reliable small machines of this type, but the idea is not so fantastic as it at first appears, and without doubt the flying torpedoes of the air will enter the realms of actuality." It is, of course, quite impossible for anyone to say what will or what will not come to pass in the future. Up to the present the 219
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