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Aviation History
1913
1913 - 0022.PDF
I/LIGHT JANUARY 4, 1913. Edited by V. Rocket-Planes and Gunpowder Motors. A CORRESPONDENT, Mr. L. F. Hutcheon, sends us particulars of some experiments he has lecently been making with what he terms rocket-planes, i.e., a model aeroplane in which the ordinary rubber motor is replaced by a gunpowder one—in this case a rocket. He says : " When reading ' Replies in Brief in FLIGHT, November 16th, 1912, I noticed the suggestion put that a certain person should try a ' rocket.' Thinking the matter over, I came to the conclusion that the idea might be a really feasible one. The result was that I fitted up a very light model, shown in Figs. I and 2, without rubber or propellers, and with the head of a rocket fitted on behind. The model was taken across to a field, and a roll of oil cloth spread out. The first trial was a failure owing to the model running off the oilcloth. The second also failed owing to too little elevation. The third rose in about 4 ft., and flew about 20 yards, only descending because it had been switchbacking on account of over elevation. My stock of rockets (price 3 a penny) being exhausted, and it being early closing day, my experiment had perforce to stop. But my firm belief is that the model, when fitted with a more powerful rocket and correctly elevated, would traverse a distance of 300 yards. A poiDt about cheap rockets is that they JOHNSON, M.A. before the Wright Brothers had thought out and invented their method of launching aeroplanes, so eminent a scientist as Lord Rayleigh proposed the principle of the rocket as one that could very possibly be employed for initial launching purposes, and in the past, Sir George Cayley (a man about a hundred years ahead of his time) experimented with a gunpowder motor. So far as the present or immediate future is concerned, the only case in which it might be of use is in experiments relative to the launching of hydro aeroplanes. One of the chief troubles in launching a hydro-aero plane is the thrusting down of the nose due to the high centre of thrust of the propeller. Hydro-aeroplanes, if sufficiently powered, invariably leave the water once they can be got to hydroplane. We are quite sure that a series of very interesting and possibly valuable experiments might be made with a couple of dozen penny rockets and a suitable model. The experiments, say, to take the nature of an investigation to determine the effect of an alteration in the height of the centre of thrust in relation to the launching of the model. When we desire to obtain anything in the nature of a flight (of any duration), we should, I feel sure, have to use larger rockets ; the flight of larger rockets being comparatively slow with respect to I PRO CENTRE. OF C|RAVITy PROTECTOR CLARKE- li'DIAM ALUMINIUH WXEE ALUMINIUM RIBBING, U SECTION BROKEN STICK, OF ROCKE-T 2.FT 5 INS. — •irT. 6IN3. riGv 1 , „ ELEVMORV/ITM Y- 55 *! BENT DOWN TIPS ROC KELT-^ LF hUTCt-lEONS) 'ROCKET-PLANE! tlODElL WEIGHT WITHOUT ROCKET 15 OZ5. do not explode at the termination of their sparks, &c., a decided gain. An advantage about a rocket-plane is that the fuselage need not be over strong, as the strain and torsional forces of the rubber are entirely done away with. Also since there is no torque, &c, the flight path is far more likely to be a straight one. I hope to experiment more with this type of motive power." Commenting on the above communication, a certain number of experiments have been carried out with model aeroplanes in which the motive power was a rocket. Nearly three years ago I made a few experiments, and so far as I remember the best results was a flight of 150 yards. The rockets used were penny ones. In one of the early K. and M.A.A. competitions at the Crystal Palace one of the competitors turned up with a "rocket-plane," to the great disgust of the other competitors, whose language and remarks re the same were, we distinctly remember, far more forcible than polite. The machine made but one flight of great height, and about 100 yards in length, ending its career (to the great joy of all the other competitors) by plunging head first down on to the hard stone bottom of an empty fountain basin, and smashing itself to " smithereens." Since that time I have never seen a rocket-plane in any competition. Nevertheless it by no means follows that some use might not be made of it in aeronautical work. Many years ago, those of smaller size. The flight, for instance, of a J lb. or 1 lb. rocket is quite majestic with regard to height and beauty of ascent. The small ones are certainly much less suited in this respect, there being too much in the nature of an initial burst off, a rush, and all is over. As the ingredients of the rocket composition are consumed the weight naturally becomes less, and therefore the rocket should be attached at the centre of gravity of the machine, if possible. We should also have the centre of thrust or reaction pass through the centre of pressure. In fact, owing to the extremely energetic nature of the motive power, it is, perhaps, even more important than usual, that the centres of gravity, of head resistance should be coincident, and the propulsive action of the rocket pass through this same point. The rocket is not the only form of gunpowder motor that has been designed, and even put on the market for models. We have in our possession one on the turbine or Catharine-wheel principle, i.e., a rotary one to which a propeller can be attached. We have not been able to obtain any satisfactory results with it, however ; more than one reader can no doubt call to mind that Catharine wheels of very small size are, generally speaking, very successful, but the larger sizes quite the reverse, and the above-mentioned motor appears to be no exception to the rule. 22
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