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Aviation History
1910
1910 - 0877.PDF
OCTOBER 22, 1910. friends from foes in the air ? The problem is an impossible one to solve, for no distinction will exist, as all aerial vessels present the same aspect when viewed from below. The only way out of the problem is, on the declaration of war, to treat all overhead vessels as enemies. Sydenham. G. H. LANE. I/LICHTI TERMINOLOGY. [834] I suggest that airmen who drive mono and biplanes be called in future planers. It is short and easy to pronounce. Furness Abbey. J, H. BOOLDS. THE GULL'S TAIL. [835] Referring to Mr. Best's letter (693), I am sure many aeronautical enthusiasts must have noticed that gulls keep their tails closed except when alighting, and that they possess particular gliding capabilities. After carefully watching them I constructed several small paper models with crescent-shaped wings and no tail. I found that when the e.g. was well forward and the tips turned up that they possessed great stability ; with one model I obtained a glide of 32 yards. I believe the Weiss monoplane now at Brooklands is based on the " negative " tip principle. Newcastle-on-Tyne. C. IAN BURRELL. FEES FOR PASSENGER FLIGHTS. [836] I have read with much interest your descriptions of various flying meetings and flying news, and was especially interested in your accurate accounts of the Blackpool Carnival. As I almost lived on the ground for three days during the first week, I am able to vouch for the faithfulness with which you reported it. As a " man in the street " I have always taken a keen interest in flying. My first sight of a machine in the air was the never-to-be-forgotten arrival of Paulhan at Didsbury on 28th April last. I stopped out all night and was well repaid. I also witnessed all the flights made by Grahame-White at Halifax last June close at hand. Now all this has begot in me a keen desire to obtain the experience of an actual flight, and I should be greatly obliged if anyone could suggest a way, short of the heavy fees at present prevailing, whereby I could obtain a flight as passenger. I tried my luck at Blackpool in this respect during the " lottery week," but had no good fortune, and could find no person holding a ticket, or willing to sell one. I am convinced that if only a few experienced aviators realised the position, and gave flights at, say, lew. to £1 \os. a time on calm days near a big city, they would find their pockets as well lined as from a great race meeting. Hundreds of people who, like myself, cannot afford ^10 10s. a flight, would gladly pay above prices for a short passage through the air. Manchester. P. A. AMOS. AERONAUTICAL TERMINOLOGY. [837] In reference to the above, I should like to make one or two criticisms and suggestions. The term " plane" is proposed for the supporting surfaces of flying machines. I would suggest that " sustainer " is more expres sive and also more correct, seeing that the surfaces are curved, not plane. This also puts " aeroplane " out of action. I don't see any thing to beat " flyer " myself. I would suggest that instead of the awkward and, to most people, unintelligible term " vol plant" the more concise and expressive word " coast" should be used. It is stated in the latter part of the article that the sweep of a sustainer or plane is approximately equal to its chord. I should like to know the reasons for this statement, as it appears to me much more likely that the effective sweep is about equal to the difference in level between the fore and aft edges of the sustainer. My reasons are these. Suppose we have a thin, flat surface, placed horizontally, this would have no sweep at all. Suppose it were then bent so that it had a slight camber, the aft edge being brought lower than the fore edge. It would then deflect a thin stratum of air. If we continued to increase the camber in this way, the sweep would be increased, though at the same time the chord would be decreased. Perhaps I had better explain what I mean by effective sweep. I would define it as the depth of an imaginary stratum of air, every particle of which is supposed to have the same acceleration, and which would give the same lift and drift as the stratum of air actually rdeflected by the sustainer, in which, owing to the com pressibility of air, those particles more distant from the sustainer have less acceleration than those near to it. Bradford. E. B. PAUSEY. HENSON AEROPLANE AND THE DIHEDRAL ANGLE. [838] Mr. Vernham (625) may not have access to the book recommended by Octavius (694). If I remember rightly, a description of the Henson aeroplane appeared in one of the issues of Fry's Monthly about last April. Concerning, the dihedral angle, Mr. Wetter's letter (696) raises a question similar to one which occurred to me lately. Part of the function of the dihedral angle is, I believe, to assist other lateral stability devices when turning a corner. It seems to me that the air banking on the outside of the curve will act as does the sudden side wind mentioned in Mr. Wetter's letter, and tend to increase the tilt. ANDREW FORSON. AEROPLANE EFFICIENCY FORMULA. [839] I enclose a formula for the efficiency of an aeroplane which may be of some interest to your readers. The efficiency of an aeroplane is the ratio of its weight multiplied by its velocity, to the horse-power of the engine multiplied by the WVD ratio of lift to drift. Thus, E = ,„ , where E = efficiency* 375 HL W = total weight in lbs., V = maximum velocity attained in m.p.h., D = drift of planes, H = h.p. of engine, L = lift of planes. This formula includes the efficiency of the propeller and motor. If the efficiency of the planes alone is required, it is given by WD the formula E' = -=-=, where T is the thrust of the propeller. These formulas have the advantage of giving the efficiency in the form of a fraction, from which the percentage efficiency can be obtained. If applied to successful aeroplanes, the results should be interesting, but as I have no complete data as to the ratio of lift to drift of the various machines, I have not been able to work out any efficiencies. Leamington Spa. G. B. BENNETT. [In the first of the above formula;, W and L cancel, thus leaving TV the expression in the form E = , , where T = thrust • drift, V , , 375-h-p.' This is, of course, the efficiency of the power plant inas much as it equates power consumed to power provided. An WV expression E = j-— might be employed with some reason as a measure of the overall efficiency of a machine. The lift efficiency L of a plane is ^..—ED.] THE NEALE BIPLANE. [840] My attention has been called to a letter appearing in your last issue from Mr. Bertie Rippen. Mr. Rippen's locus standi here at the time the photograph referred to was taken was that of " one of the Neale pupils "—nothing more. Later on, when delivery is executed, he will own a quarter share of a " Neale VII." Mr. Rippen's statement that he originated the scheme and found the whole of the money for building a " Neale VII " is incorrect, and in view of the importance of the provisional patents covering the screening control, might mislead the aviation world. When the validity of the Wright Brothers' patents for wing warping and ailerons, as used on every successful machine excepting " Neale VII" are tested in this country—as, sooner or later, they are certain to be—the screening control patents will assume great value, not only because they are obviously the only successful alternative method at present available, but because they will be generally found, as my expe rience has shown me, to be a more stable and easily managed method of control than wing warping or ailerons, eliminating one movement of the control. It is therefore of importance for me to state that Mr. Bertie Rippen had no hand whatever in originating the scheme, other than in piloting the machine during his tuition. Thanking you for giving space to this correction. Brooklands. J. NEALE. it »*ti Ima PARACHUTES. [841] I should be much obliged if one of your numerous readers would tell me how many square feet of material are required in a pafachute to lower an average man from practically any height, and what is the best material to make same of. Benton. H. E. VAUGHAN. 875
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