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Aviation History
1920
1920 - 0166.PDF
FEBRUARY 5, 1920 MODEL AEROPLANES - cr ^»»-i NOTE.—All communications should be addressed to the Model Editor. Hints on Flying Model Aeroplanes IN order that the machine will do a straight flight, the planes must be carefully aligned. To do this, hold the model by the propeller cross-bar with both hands up to the eye, and see if the cross-bar, back plane struts and front plane strut tips are in alignment witti one another. If they~are not, it will result in the machine being out of balance laterally, which will cause it to make sharp circles and to dive. For circular flights, place the planes slightly out of align- ment with one another. The maximum number of turns to which each propeller may be wound with safety should be applied only after they have been wound several times to a less number. Winding to a greater number is liable to tire the elastic rapidly. When a strand in one of the motors breaks, overlap the two ends, stretch and bind them with strong thread. Examine the elastic before flying the model, and search for a join in it, which will be found to be bound in this manner. • For a first trial flight, and to accurately adjust the model, wind only about 250 turns on each propeller. The propellers must be wound outwards, curved surface first. Be careful always to wind the propellers each an equal number of turns when the machine has twin screws. When wound, hold the machine with one hand just behind the deepest part of the fin, and hold the two propellers with the other slightly above the level of the head, let go the propellers and then quickly launch the machine forward (as if throwing a dart) being careful to give it a good push and to send it horizontal and not up or down. Until very skilled, always launch the machine straight against the wind (if any), and choose a calm day for the first experiments. When in skilled hands, the machine can be flown in almost any wind. Choose a good open space in which to fly the model. Re- member that it flies for -more than a quarter of a mile when fully wound. If the model is properly adjusted, it should glide for a considerable distance when launched briskly and very slightly downwards by hand, coming to earth without any shock or bump. If, in flight, the machine appears to rise and dive alternately (following an undulating path through the air), it shows that the front plane should be screwed down a little. The ex- planation of this is that the front plane, having too much " lift," causes the machine to rise too rapidly for its own power. It, therefore, soon shows up, and in order to recover the speed at which its planes sustain it in the air, it dives automatically, attains the necessary speed, and then rises again, owing to the same cause. The machine when correctly adjusted should leave the hand quite horizontal, then, when a few yards away should rise very rapidly to a height of about 70 ft., at which height it should remain, perfectly steady, until -She speed of the propellers is perceptibly lessened, when it should glide gradually down to the ground. If the machine, after leaving the hand, dives straight for the ground, the front plane will require raising a little, as it will not be " lifting " sufficiently. Remember always to send the model off at a good speed. A perfect launch is at the " flying speed " of the machine, which is about 20 m.p.h. Before each flight see that the boom is perfectly straight, and that the plane struts are correct. They can both be bent straight by hand very easily. ^ (To be continued.) The Aero Models and Research Club We have received the following letter from Mr. Burchell of the Aero Models and Research Club :— " The club proposes to open its 1920 season during the Easter holidays, and it is hoped that a number of newly- designed models will be ready for this opportunity of putting them through their tests. There will be an exhibition of parachute descents from models in flight, which should prove interesting. Mr. White is expected to be on the flying ground during the meeting, and any aero modellist who may have seen his photographs will appreciate his value to the club in getting snaps of machines in flight. During the meetings it is proposed to hold various competitions, provided there are sufficient entrants. The prizes will consist of a model and parts presented by Mr. Burchell and Mr. Coleman. If circumstances should warrant, the club will also offer a prize for the best total of six flights during the Easter flying. Times will be published later. " It may be of interest to some of your readers to know that in the research department Mr. Coleman, with the assistance of Mr. Burchell, has been working on power plants for models, including electric with a special kind of cell, and should it prove successful, details will be published. " Any modellist wishing to partake in the Easter flying will be most cordially welcome, and any further enquiries to the following addresses will receive our best attention :— " The Aero Models and Research Club, late the Finsbury Park and District. Secretary, Mr. Burchell, 63, Belmont Street, Kentish Town ; Assistant Secretary, Mr. Coleman, 30, Hanley Road, Finsbury Park, N. 4. Flying ground. Parliament Hill Fields." Aston Type Compressed Air Engine Be'ow I show a three-cylindered compressed air engine made on lines suggested by W. G. Aston several years ago. The cylinders are sweated on to flanges on the crank-case. Inlet is operated by means of a ball valve operated by a tappet- rod and cam. The stroke is | in., and the bore \ in. ; total weight 1£- ozs. The engine is, of course, stationary ; exhaust taking place through ports drilled in the cylinder. The pistons are castings, of aluminium or brass, and are made as seen in sketch, showing a mould turned in steel. The brass is melted and poured in, the top of the piston being cleaned up if necessary. The conical portion of the male mould should, of course, be made to the desired internal shape of the piston, and a hole should be drilled in its centre to form a lug on the casting, the lug in turn forming a bearing for the gudgeon-pin and connecting-rod. Replies to Correspondence CONSTANT READER (NO address).—Your question is too vague. Cannot you give more lucid details as to your requirements ? - J. C. H. G. (Cardiff) and R. W. (Bournemouth).—Wereplied direct. 166
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