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Aviation History
1915
1915 - 0583.PDF
AUGUST 6, 1915- ITltGHTl ALL communications in connection with this section should be addressed to the Model Editor, Flight, 44, St. Martin's Lane, London, W.C. Correspondents are requested to write on one side of the paper only. Machines With More Than Two Propellers. By V. E. JOHNSON, Esq., M.A. ONE result of the war has been the speeding-up of the development of those particular types of aeroplane which are especially suitable for fighting purposes. Now it is the essential feature in the development of any fighting weapon to render it, if you can, more formidable than that of your opponent. It is a matter, therefore, of no surprise to learn that the various belligerents are endeavouring to produce a larger, more complex and more formidable weapon than their opponents ; in other words, machines of more than one or even two motors and two propellers, of much larger span, and in one case at any rate a double fuselage. The latter, which has been used by the Germans, according to newspaper accounts, was capable of flying round and round those attacking it. In other words, it possessed a greater speed factor, apart altogether from any other advantages it might possess in gun-carrying or bomb-dropping devices. In the case of what are commonly called " Ocean Greyhounds " and other swift-moving vessels one always finds them provided with more than two separate engines and propellers. Taking the case of the aero models, it is, of course, a well-known fact that, given similarity of design, the twin-propellered model is swifter than that having only one propeller. Now, so far as we know, very little has been done to develop models of a more complex nature, possessing, say, three, or even four propellers and motors. The writer designed, some time ago, a four-propellered symmetrically arranged " flying stick " model. He was unable at the time to carry out many experiments with the same, but sufficient was done to show that such a model could be got to fly, and that experiment alone was necessary to develop it successfully. In flight the model was very swift. The propellers were so arranged that two were pushers and two were tractors. The framework was T-shaped both ends, and the rubber motors crossed one another in pairs. So far as models with a double fuselage are concerned, we cannot call to mind any of this character which have actually been constructed. If such have been experi mented with we should be extremely glad to have full particulars of them, together with any results which may have been obtained with this species of model. In a sense one may look upon the " A frame " flying stick model as such a type in embryo, and we do not think it is any exaggeration to claim that the double fuselage machine (which is said to be so successful in the type referred to) first existed in model form. It may be that models having more than two propellers have been tried, but the point is have they been tried sufficiently, and have any really been designed with an idea to the future development for a full-sized machine ? Have they not rather been made with a view to just trying the idea to see what would happen ; or it may be even just for the sake of making what was considered to be a " freak " model ? Such things have been done. Experiments along such lines are nevertheless well worth conducting, more especially if geared rubber motors were used so as to keep the dimensions of the model more in conformity with those of its full-sized prototype. The best type for such experiment wouldappearto be a biplane with the propellers tihimlihe main plane. The chief points to note with such a model appear to be itt speed, stability and gliding properties. The propellers should be those which are provided with a contrivance which prevents them from revolving when the model is gliding. The rubber motors (assuming rubber to be used) should be enclosed in light streamline bodies, assuming four propellers to be employed ; or two of them could be enclosed m the double fuselage. These fuselages could be parallel or nearly so. In the case of more than two propellers only one extra motor container need be used, and in the case of four propellers only two extra need be used. Such models are, of course, innovations, and innovations, at any rate in open model competitions, have not always been re ceived with that favour which one might have expected. At the present time there are those that consider that two motors in a full-sized machine are really no better than one, if as good, and that the machine of the future must carry more than two, in all probability not less than four motors, with possibly four propellers, or it may be two, suitably geared ; all of which goes to show that the problem of the multi-motored model is one which should not be neglected. Of course it is more difficult and far more troublesome in many ways than the single or twin-propellered model. It is a problem which probably only an enthusiast would care to tackle. The initial failures are likely to lie great and many, but when once success of only a moderate character, say, had been obtained there would be created an entirely new type of model, with boundless possibilities before it. © ® ® ft AFFILIATED MODEL CLUBS DIARY AND REPORTS. Club reports of chief work done will be published monthly for the future. Secretaries' reports, to be included, must reach the Editor on the last Monday in each month. South-Western Aero Club (373, BRIXTON ROAD, S.W.). MEKTINGS at Brockwell Park every Saturday at 3 o'clock, weather permitting. Monthly Report.—On July 3rd, Mr. J. W. Reid read a most interesting paper on " Tractors, which was followed by a very lively discussion, in which Messrs. Peel, Clarke, Prodger, and Howse took part. Mr. Reid'»tractor, with a flexible rear-edged main plane, has been making some excellent high flights of 40 sees, average duration. Mr. Howse's hydro, has also been out. Towards the end of the month a new 4 ft. span tractor by Mr. Howse made its appearance, and flew well at the first attempt. Flights of over aoo yards r.o.g. have been accomplished, but no durations have yet been taken. Messrs. Prodger and Clarke are busy on new tractors, which should be out very shortly. UNAFFILIATED CLUBS. Finsbury Park and District (66, ELFORT ROAD, HIGHBORY, N.). Monthly Report.—Flying last month was well up to the average in spite ot inclement weather on some occasions, and some new machines have appeared, including biplanes by A. Richards and F. E Rayner. Mr. Richards' tractor biplane, which flew moderately fast, was very stable laterally, and the wings were of high aspect ratio, while in Mr. Rayner's machine (also a tractor), the a/r being about 5-1, the lateral stability was not so marked, although longitu dinally it was more stable than Mr. Richards' and travelled slightly faster. Mr. B. H. Barnard's tractor biplane, to which has been fitted a covered fntcla^f. A model oi a B.E. made by a Scotch reader, Mr. Jamtes Ditthie. 583
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