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Aviation History
1913
1913 - 0392.PDF
I/LIGHTI APRIL 5, 1913. * sagging' for want of a better term, which would signify toaXpropor tionate loss of power which is apparent in a skein of rublier running to 4 ft. or more. I think that every aeromodellist is agreed that once the 3 ft. length is passed an appreciable loss of power is apparent, otherwise I might ask : 'Where are our 5 ft. or 6ft. models ? ' Some time ago I made a 5 ft. 6 im. model, and after exhaustive trials its best efforts were some 200 yards. To obtain even this, 40 strands of A rubber had to be employed. Re your suggestion of looping up the rubber, I used this device some two years ago, but discarded it, as I found that the kinks invariably caught (temporarily, of course) and caused vibration. I afterwards trkd a wide loop of tin rounded off at the ends, but the friction was unsatisfactory, and I obtained the best results with the unhampered skein. I quite agree that a competition for stability and slowness of flight is one that should be worth the consideration of the K. and M.A.A., but I think that there would be some difficulty in getting a model to fly at 10 m.p.h. in a 20 m.p.h. wind. " Personally, I have a weakness for the large and slow-flying model, and the 4 ft., Si oz. model to which I referred took (in the Gamage Cup Competition) 80 sees, to fly, in a straight line, 500 odd yards, i.e., about If "J m.p.h. Of course, there is the spherical line of flight to be allowed for. This model's best duration to date is •94 sees., and my conclusions are that the large model must be built exceedingly light if it is to be (in the opinion of the modellist, at any rate) a success." It is some time now since the writer tried any experiments with the type of model referred to by Mr. McBirnie, but he certainly failed to notice that proportionate loss of power referred to—in models up to at any rate 4 ft. 6 ins. in length ; he also always made use of the wire loop when using long skeins of rubber, preferring the (very) occasional "catching of the kinks" to the continual vibration caused by the long, untwisting skein of unsupported rubber. This discussion once again raises the question of sizes and weights of models, and durations and distance*. Theoretically, I know of no reason why a model 6 ft. in length should not fly so far as one 3 ft., provided the proper design, &c, be employed. Undoubtedly, the problem is far more difficult mechanically. Experiments are, undoubtedly, much needed, especially with heavier rubber-driven models than those in general use. Has anyone as yet tried any experiments with a machine fitted with four propellers! We remember once seeing in a competition, some two or three years ago, a machine with two propellers and two tractors. Unfortun ately, this model promptly smashed itself to pieces at the first attempt, since when we have seen no other. Given certain con ditions, however, the experiment certainly seems worth a trial. The Bonn-Mayer Petrol Motor. The following are the principal weights of this interesting motor, which we had the pleasure of seeing running a few days ago. The weights given are for the plant complete, as running wi*.h fuel and oil for about a five minutes' run, fitted with a 3-ft. propeller and ® ® KITE AND MODEL AEROPLANE ASSOCIATION. Official Notices. British Model Records. u„ j • « 1 f Distance ... A. E. Woollard ... 477 yards. Hanrl-launched ...|Doration ... A. F. Houlberg ... 89 sees. Offgrnnnd (Distance ... G.Rowlands a3* yards. .Duration ... A. F. Houlberg ... 51 sees. Hydro, off water ... Duration ... G. P. Bragg.Smith... 25 sees. Single-tractor screw, (Distance ... F. G. Hindsley ... 173 yards, hand-launched ...(.Duration ... J. E. Louch... ... 44 sees. Do., off ground ... Duration ... J. E. Louch 40 sees. Annual General Heeling.—The annual general meeting was held at Caxton Hall, Westminster, on Thursday, March 27th. Mr. H. W. Browse was elected la the chair for the evening. The officers elected to serve for the ensuing twelve months were : President, Sir John C. .Shelley, Bart. Vice-Presidents, Col .1. li. Fttllerton (late R.E.), F.R.G.S. ; J. Moore- Brabazon; W. H. I lines. K.sq. (late Pres. Royal Met. Soc.); R. M. Balston. F.R.S. Advisory Council, W. B. Brooke; H. W. Browse; T. W. K. Clarke, A.F.Ae.S. ; S. F. Cod : C. Davie*; C. R. Fairey ; T. O'B. Hubbard; H. H. Groves; V. E. Johnson, M.A. ; J. H. Ledeboer, M.A., A.F.Ae.S.; F. Mayer; R. H. 1 Winchester; F. T. Pringuer; C. Rowlands; G. P. Bragg-Smith; l>r. -A. 1'. Thurston. Hon. Secretary, W. H. Akehurst. Assistant Hon. Sac, \. F. Hoiilberg. The report for the year was passed as read on the proposition of Mr. H. Browse, seconded by Mr. F. T. Pringuer. The chairman in his remarks referred to the sad loss the association had sustained in the death of Lieut.-Col. F. C. Trollope, who had done much, and on the eve *if his illness made arrangements to hand a cheque to the secretary for the 1st Section of War Kite Squadron. The chairman also stated that it was necessary" that the .is-.oci.uion should have a new form of membership for those who wished to help forward the scientific building of kites and models by joining ilu- association and strengthening its hands. After a discussion it was un.mimou-.ly decided that there should be Fellows and Associate Fellows, and that all persons should be eligible subject to the approval of the council. The following to be the annual subscriptions : Fellows, £3 3^.; Associate Fellows, £1 if-; members, 5J, ; family subscription (3 or iess), tot.; junior members, under 17, a*, t*/, .Gifts of Trophies.—The hon. secretary announced that the latest trophies given to the association were : The Michelin Challenge Trophy, The London Ac-i1 -iromc Challenge Trophy. In proposing the election of Sir John C. Shelley, mounting. Propeller and mounting, I lb. 4 ozs. ; engine, carbu rettor and distributor, 6 lbs. IJ ozs. ; petrol for 5 mins., I oz. ; coil, 10-5 ozs. ; battery, 1 lb. 2 ozs. ; total, 9 lbs. 3 ozs. 398 The Bonn-Mayer petrol motor for models. As there is no difficulty in getting a 14 lbs. propeller thrust with this plant, it would undoubtedly fly a suitable properly designed and constructed model. As a matter of fact, a machine fitted with an exactly similar motor, constructed by Mr. Mayer, has already made many successful flights. The manner in which it can "shift" a 3-ft. propeller is certainly astonishing at first sight. The model would, of course, be a large one, and could weigh complete, without any detriment, well over 40 lbs. A power-driven model will rise off good ground if the thrust of the propeller be one-fourth the total weight; that gives a maximum permissible weight of 56 lbs. There should, however, be no difficulty in making the model complete to weigh 30 lbs. or even less, which leaves an ample margin for the case of the hydro-aeroplane model. Mr. Oliver's Query—Replies to. W. E. Knight, writing in reference to the above, says : " In reply to Mr. Oliver's query (of March 20th issue) for a good home-made rubber lubricant, I give the following :—Take ] d. of soft soap, 2 ozs. of glycerine, 8 ozs. of water ; boil together in a saucepan until they have the consistency of golden syrup, then pour out into a vessel and allow to stand till cool." S. J. Upward writes: "Take water 10 ozs., ordinary white soap £ oz., pure glycerine J oz., 1 small spoonful of salicylic acid, and J oz. of graphite. When the soap is dissolved add the glycerine and acid, and the graphite when the mixture is set." W. J. Ledward says : " To 1 pint of boiling water add half a bar of washing soap, and when cool add I oz. of washing soda. This makes a very good lubricant which does not seem in the least deleterious to the rubber." Replies in Brief- J. E. REID.—An r.o.g. rubber-driven model should rise off good ground if the total static thrust be one quarter the total weight, your Sa"oz- thrust should therefore rise your model, which you say weighs 22 ozs. inclusive of everything. ® ® Bart., the secretary stated that the selection committee out of the gentlemen nominated recommended his election, and it was hoped he would be able to help the association in raising the War Kite Squadron and also the International Prize Fund. If the money needed for the international meeting in this country cannot be raised the French have offered to find it if we hold the meeting over there. It therefore is hoped that some gentlemen in this country will come forward quickly and supply the money. After the general business, the suggestions for various competitions were read by the chairman, who stated that every suggestion should be considered by the rules committees. A vote of^ thanks to the chairman brought the meeting to a close, after which a general discussion followed among the members. International Aero Motor Competition.—Class 5 for aero motors. The bench tests for this class will be carried out at the East London College, Mile End Road, by Professor J. T. Morris, on Saturday, April 12th, at 2.30 p.m. Judges and competitors should travel by District Railway to Stepney Green Station, and, turning to the left on leaving the station, the College will be found adjoining the People's Palace on the left. The hon. sec. of this association will meet the patty outside the east gate, which is the first one after passing the clock tower of the People's Palace, at 2.25 sharp. On no account enter through the People's Palace gate. All details and rules have been posted with drawings to all competitors. An official chart will afterwards be issued, giving the result of the tests, and being the first tests made officially of model engines by this association should be interesting to a 1. These tests have been arranged by the hon. sec. on behalf of the Royal Aero Club, on whose behalf they are issued. Subscriptions.—Subscriptions are now due, and should be forwarded without delay, as their early payment greatly facilitates the work of the association. 27, Victory Road, Wimbledon, S.W. W. H. AKEHURST, Hon. Sec. ® ® ® ® MODEL CLUB 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. Birmingham Aero Club (8, FREDERICK ROAD, EDGBASTON). Monthly K^rt.—During the last month some splendid sport has been Obtained with the.Haddon glider, nearly all the members of the club partaking in flights in the glider. The first real day's sport was on March 1st, when there was a steady wind blowing across the club aerodrome at about 20 m.p.h. The secretary was the first to go up, and the towers had only to start at a walking
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