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Aviation History
1912
1912 - 0205.PDF
MARCH 2, 1912. Calling the scale of the model L times full size (L, of course, being fractional), the surface aera of the model planes will be L" times full-size. The fabric, in common with all other integral parts of the model must, if the wing structure of the full-sized machine is rigidly followed in every detail, be Ls times full-sized weight, and therefore the weight of the fabric per unit surface will require to be £2 = L times full size. In other words, the scale of weight per unit surface of the fabric is the same as the linear scale. Now fabric as used on full-sized machines may be taken to weigh 5 ozs. per sq. yd., and the lightest available fabric known to me, viz., gold-beater's skin, I oz. per sq. yd. It therefore follows that if the model is to be a true reproduction of the full-sized machine in every detail, the smallest scale to which it can be built is * + 5 = | full size." We are afraid Mr. Vessey has somewhat underestimated the weight of gold-beater's skin, the best quality of which weighs at least (single skin) x^j of an oz. per sq. ft. ; this allows, of course, nothing for joining, the largest pieces in which it can be obtained being about 14 ins. by 24 ins., this would make, say, 10 percent, increase ; even omitting this we obtain not -\ but 3% approx, say, I, or allowing for joins L Replies in Brief. H. C. DAVIS.—Your apparatus resembles in some respects one used by the late Professor Langley. His consisted of a large pendulum resting on knife edges, but which was prolonged beyond the point of support, and counterbalanced so as to present a condition of indifferent equilibrium. Near the lower end of this pendulum the model was suspended, which when power was applied to it, the reaction of the propeller or propellers lifted the pendulum through a certain angle. If the line of thrust passes through the centre of gravity, it follows that the sine of this angle will be the fraction of the weight lifted—and thus the dead lift- power or forward thrust of the propellers (due to the motor) becomes known. The scale requires to be carefully graduated. Yes, we are inclined to think the large aspect-ratio the more efficient—but the problem becomes complicated, owing to the effect of compound increasing pitch, &x. ; much depends on the general design. ® ® [/JjCHT] F. WIEDMANN, Ji-N.—We do not think it possible to construct a successful petrol-engined model of 5-ft. span, but will inseit your communication as a query in next issue. E. N. JOYCE.—The idea is not new—we cannot say who first employed it—it is well known among experts as the one thing which has to be most carefully attended to when trying to make a model- fly straight. It is also most efficacious (as you have found mil) when desiring to make a model circle. Try the small tin in front, and let us know if the model still dives. LAWRENCE MINOT.—From the drawing you send we should naturally exj>ect the frame to buckle; it is insufficiently stayed. Change it to the usual triangular type, and use king-posts and cross- stay it ; or try a J_ frame, it is quite probable you might l>e more successful with this type. Your framework must be wtf (it is absolutely essential) to torsion and twisting forces :is well as to direct pulls. F. H. H.—Of one screw only—since both are working simul taneously. C. C. HORNER.—The photo sent illustrates in principle the same idea as was patented years ago by Mr. G. P. If. Smith—but being triangular instead of curvilinear is inferior to it with respect to. lateral stability. C. A. BURKITT.—The photos you send are far too small to show the details mentioned in your note, and in a case like this photos are unsuitable. If you care to send along a proper set of scale drawings we shall be pleased to consider them. W. G. BLOE j T. H. BULLOCK.—To solder ribs to edge of piano- wire wing-frame is quite easy if the ends of the ribs (; ") are turned round at right angles so as to lie along the wire frame and bound with very fine copper wire (as used in some electrometers), and then neatly soldered. R. BAGI.KY.—For stability your two planes must form a V, opening skywards. Try a rather larger tail, fitted at rear with two- small, adjustable, horizontal rudders. We should say you might safely give another 50 to too turns, if well lubricated. Use valve- tubing on your hooks. ® ® THE KITE AND MODEL AEROPLANE ASSOCIATION. OFFICIAL NOTICES. Interoational Model Meeting.—Lord Montagu of Beaulieu has kindly offered the Council a trophy, which will be called The Cat Trophy, and the hon. sec. has accepted same on their behalf, at the same time thanking his lordship for his gift. Details, &.C., will be published as soon as possible, but the Council still require some donations, and four more trophies. Will wealthy readers, who have the development of aeronautics at heart, rally round and help the cause by giving the support needed. Aerial Kite Signalling (Morse Code).—Anyone now wishing to obtain the complete outfits, approved by the association, can obtain them from Messrs. Brooke and Westhorp, I6A, British Grove, Hammersmith, or any member will be informed of the days the association's honorary instructors will instruct the Territorials in the use of this system on Wimbledon Common, if he will write to the hon. sec. Competitions.—The Chairman of the Aeronautical Research Society (East London College), has asked the association to co operate with them and hold a competition at their annual garden party : this the Council has agreed to do. Also the Application of the Council to hold a series of Laboratory competitions in the autumn has been favourably received by the authorities of the College, and it is hoped to be able to hold some interesting scientific competitions, and to collect some useful data. W. H. AKEHURST, Hon. Sec. ® ® ® ® 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. Aberdeen Aero Club (Sec, A. SEFTON, 387, HOLBURN STREET, ABERDEEN). ON Saturday Mr. L. Gray's model continued its excellent performance of last week and brought the distance record up to 1,200 ft. Mr. Wilson obtained a record duration flight of 47 sees. Mr. Wilson, junr., had some excellent flights with a tandem mono plane. Mr. G. Geddes, a young enthusiastic member, repeatedly obtained 35 and 37 sees, duration. Meeting to-day, Saturday, at 3 p.m. Aero-Models Assoc. (N. Branch) (Sec, MALCOLM B. ROSS 15, HIGHGATE AVENUE, N.). ON Saturday last, at club's Finchley ground, Mr. Hindsley brought up three models and Messrs. Root and Partridge a mono plane each. Mr. Corder's old-type " Argecie " monoplane on one occasion got up to over 150 ft. and vol planed down at a fine angle. Members and all interested are asked to turn up in force for a " Duration" competition (Saturday), at Viver's Farm, Bishop's Avenue, East Finchley, at 3 p.m. Fee 3^., shared for prizes. "Distance" competition for " Mann" monoplane set of parts presented by the makers. March 16th, 3 p.m. Competition open, no entrance fee. Birmingham Model Aero Club (Sees., R. COBHAM, G. II. WOOD, 8, FREDERICK ROAD, EDGBASTON). LAST Saturday the longest flight was 48 sees., by Mr. E. Trykle. Mr. G. Wilde's Trykle-type model made fine flights, ending generally in a glide from about 30 ft. ; longest duration, 44 sees. ; Mr. W. Lunn's model reached a height of quite 100 ft. Mr. G. Baker, with a 5 ft.-model, and Mr. G. Mason, with his old twin-screw model, were also flying. To-day (Saturday) duration competition for the W.II.C. model, amongst juniors. Usual monthly meeting at Bell Inn, Phillips Street, March 4th, 8 p.m. Club business, lectures and discussions will take place. Blackheath Aero Club (Hon. Sec, A. E. WOOLLARD, 48, HAFTON ROAD, CATFORD, S.E.). ON Saturday general meeting was held at the Central Hall, Peckham, Mr. H. II. Groves in the chair. The officers elected to serve for the ensuing year were :—President, Mr. C. E. Rippon ; Vice-President, Mr. B. Woollard ; Committee, Messrs. A. B. Clark, H. Coomber, J. H. Dollittle, H. H. Groves and F. Plummer ; Hon. Sec, Mr. A. E. Woollard. The following club records were passed :—Distance (hand- launched), 2,265 ft- > duration, 6l sees. ; and distance (self-rising models), 762 ft. All these records are at present held by Mr. A. B. Clark. 205
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