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Aviation History
1912
1912 - 0019.PDF
JANUARY 6, 1912. H. S. SADLER.—You will find what you require in," Flying and some of its Mysteries," Chapter IX. WALLIS SHERLEY-PRICE.—It is impossible to answer your questions without further information re area of supporting surfaces, full particulars as to rubber motor, pitch of propeller, and general dimensions of your model. The vibration of the untwisting rubber motor would not cause the results you state, but an unbalanced pro peller might have something to do with it. Ball bearings are no advantage on small models, whatever they may be on very large ones—rather the reverse. It looks as if your machine were under powered. S. CLARKE.—With respect to your queries concerning "pro pellers," you will find them all fully (much more fully than we could possibly deal with them here) answered in "The Theory and Practice of Model Aeroplaning," Chapter V. P. BRYANT (MELBOURNE).—In constructing a long-distance flyer, the length of your central stick or motor rod should be at least twice the span of your main plane. You must use twin propellers, care fully and accurately tuned to give exactly the same thrust, or your model will circle. These propellers should, of course, be of opposite pitch. Your supporting surface should not possess more than medium area. In the drawing you enclose your dihedral angle is far too large—the slightest angle should be enough—upturned tips are pro bably better. Your elevator is also much too large, see December 16th issue. No, half an inch is not thick enough ; try three-quarters to an inch. You will find your other queries (not already answered here or in back numbers, which please consult) dealt with in future issues. L. G. RYLEY.—To get your model to fly straight you must first carefully adjust and tune up your propellers so that they give exactly the same thrust. Test them at the extremities of a horizontal arm carefully balanced and pivoted about its centre, so as to turn about a vertical axis, using same weight and disposition of rubber for each (/ycHfj motor. Wind both up equally and release at same instant; if each gives the same thrust there will be no rotation, if one gives a greater thrust than the other there will be rotation. Apply two tests at least, interchanging propellers to make sure—carefully tune up your propellers, re-pitch blade area, Sec, until there is no rota tion, i.e., until the thrusts exactly balance. Then try again on your model—carefully noticing if it exactly balances laterally—if the distance of your bearings is exactly the same from the centre of the plan-form of your machine—if the weight of your two rubber motors is the same, &c, &c, no fin or rudder per se will make your model # ' straight—a rudder is to steer by. A vertical fin is preferable (for stability purposes) behind than in front. We should not advise you to use one—at any rate, try first the method we have suggested. For carving propellers from the solid, the formula you give : P = 3f x D x - Where P = pitch and D diameter of propeller, and / and w thickness and width of block before cutting is generally regarded as reliable. The tip of the propeller-blade running diagonally across the end section of the block. REGINALD OATES.—We will propose dealing with the model hydro-aeroplane later on. In the meantime you can easily try a few experiments. Make your floats as light as possible, and give them a fish shape somewhat blunt nosed, but with finely-tapered stem, and fix them to your model (presumably), so that their centre of gravity is slightly behind the centre of gravity of the rest of the model. Do not lower your centre of gravity any more than you can help. Judging from the very poor performance of the model you name at the Wakefield competition for self-rising models, you would be quite unable to do as you suggest. In any case you will probably have to considerably increase your power. ROBERT H. HARRISON.—We have not received your communi cation. Write again, and enclose stamped and addressed envelope, and we will reply as you suggest. (B © ® ® PROGRESS OF FLIGHT ABOUT THE COUNTRY. NOTE.—Addresses, temporary or permanent, follow in each case the names of the clubs, where communications of our readers can be addressed direct to the Secretary. We would ask Club Secretaries in future to see that the notes regarding their Clubs reach the Editor of FLIGHT, 44, St. Martin's Lane, London, W.C., by first post Tuesday at latest. MODEL CLUBS. AerO'Models Assoc. (N. Branch) (15, HIGHGATE AVENUE, N.). A VERY enjoyable meeting was held at the above address on the 23rd ult., there being a good turn out of members. Mr. R. G. Corder kindly brought along several cards of samples of Clarke's model accessories, which provided considerable interest, as close inspection of the articles was thus afforded. There were also some models and model propellers to be seen, which were not, however, put under test in the room, though interesting experiments were carried out with a paper plane, constructed by Mr, Brosse, and which closely resembled the Gamage " Curva." On Boxing morning, the secretary, Mr. Ross, paid a visit to Palmer's Green, and despite the rain, spent quite a good morning's sport at the hands of the Palmer's Green Model Club, where some good flights were put up. Another social is to be held at 15, Highgate Avenue, N., on Saturday, January 13th, at 7 p.m. Will every member try and turn up and bring anything of interest in the model aeroplane line with him. Model competition on January 20th. Full particulars next week. Joint secretary with Mr. M. B. Ross is Mr. H. Brosse, 9, Clifton Road, Crouch End, N. Birmingham Model Ae.C. (8, FREDERICK ROAD, EDGBASTON). AT Billesley Farm there has not been a busy appearance during the holidays, no doubt this being due to the weather. There was, however, a slight improvement this week-end, both in the model flying and in the attendance. Mr. E. Trykle, who has not lately done any record flights, showed an improvement, sometimes getting flights of about 300 yards. Towards the end of the afternoon there were several other models brought out. Mr. M. Vale was flying a converted monoplane, this once being a biplane, and obtained some very satisfactory flights. Mr. W. Lunn was again getting some excellent results, and towards dusk gave an exhibition of gliding with his model from the roof of the shed. A large number of fine glides were obtained, the model's gliding angle being over I in 7. A little of Mr. G. Haddon Wood's old flying was again seen, his model had, however, the peculiarity of taking the course of the letter S. This could only be attributed to the elastic giving off an uneven torque. The flying of Master Stamp's was as good as has been seen for several weeks, his flights finishing with splendid glides. A monoplane having a high aspect ratio, built by Mr. A. F. McManus, was doing plenty of fast flights of about 1,000 ft. A search for this model after the last flight of the day had to be made owing to its having outpaced its constructor, and losing itself in the dark, but it was eventually found at a spot a long way from where it was assumed to have dropped. Blackheath Aero Club (196, BROCKLEY ROAD, BROCKLEY, S.E.), ON December 25th and 26th many members were experimenting at the Kidbrooke and Lee grounds, and Messrs. Dollittle, Whitworth, and Brough were competing for the rose-bowl presented for the longest straight flight with a " tractor " model. The result was in favour of Mr. Dollittle, who made a flight of 318 ft. with his original Gnat monoplane, as illustrated in FLIGHT last week. The perfect stability of this tractor has to be seen to be appreciated. On Saturday last, at Kidbrooke, Mr. C. Ford obtained his second- class certificate with a good flight of 287 yards, and Mr. L. Brough, flying a new 4-oz. Victor monoplane on Blackheath, gained his first- class "ticket" with an excellent flight of 1,524 ft. The model was not aided in any way by a wind, as a dead calm prevailed at this moment. Messrs. Collins, Egelstaff, Woollard, and Waghorn were also flying at Kidbrooke, and Messrs. Clark, Whitworth, Dollittle, Packham, and Pizey were at Lee, and Mr. F. Plummer easily gained his second-class certificate with a large " Meteor" mono. Mr. Plummer's model attained high altitudes, arid was greatly admired for its steady flying. The following new members were elected :—Mr. G. Brown, of New Cross ; Messrs. F. Clarke and E. Hock, of Crofton Park ; Mr. S. Martin, of Lewisham ; Mr. G. A. Morley, Woolwich ; and Mr. F. Packham, of Chislehurst. The committee expect many additions to the membership list as a result of the club's first exhibition, which will have been held by the time these notes appear, and the Secretary will be pleased to supply full particulars to anyone making written application to the above address. On Saturday, January 13th, there will be open competitions at Kidbrooke for "distance," "duration," and "steering," and 15 marks will be given for the two former events, and 20 marks for " steering," and Mr. J. H. Dollittle will present a small silver cup to the constructor of the model which gains the highest total number of marks. Flying will commence as soon as possible after 2 p.m., 19
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