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Aviation History
1939
1939 - 0629.PDF
JtAKCH 2, 1939 FLIGHT. 229 MODELS By M. R. KNIGHT Flexibility THE type of pusher model in which the airscrew is mounted at the end of a short fuselage suffers from the great disadvan- tage that the length of rubber skein and, in consequence, the length of flight obtainable, is very restricted. Mr. C. A. Rippon, whose experience of pusher models is unrivalled, overcomes the handi cap in his model " Cyrano " by placing the rubber skein within a full-length fuselage, and contriving that it shall turn' the airscrew by means of a flexible drive. This simple piece of mechanism, the outcome of lengthy experimen tation, consists of a portion of spiral spring wire of small dia meter enclosed for the most part in brass tube so that it is prevented from knotting under the very considerable stresses set up when the motor is released. Over 100 runs have been made without mechanical failure of any kind, and the designer now considers it sufficiently developed to be used in the near future in a twin-motored flying boat, for.which purpose it should be particularly useful. The ijoz. rubber motor consists of 10 yards of Jin. flat strip made up into 12 strands. The end of the front supporting hook is held in a tinplate frame, and is filed to fit into one end of the spiral drive, which consists of 22 s.w.g. wire wound on a mandrel of the same material, which is held in the chuck of an ordinary hand drill. The hand drill is rotated, and the spiral guided along the mandrel wire with the thumb and fore finger of the left hand, which must be protected with a piece ol leather if severe burns are to be avoided ! The drive, after leaving the support, passes through a curved length of brass tube concealed in the nose of the fuselage, emerging from a soldering-sleeve as a plain wire. It passes through another sleeve, and enters the dummy engine-cowling as a spiral drive within another brass tube. The final length of spiral is plugged with 22 s.w.g. wire, and sweated hard, becoming the airscrew- shaft. Friction has been reduced to a very small amount. The airscrew is ioin. in diameter, and about 14m. in pitch. While the rubber skein is being wound, which is done from the rear, the drive is held by a brake, visible on the port side of the fuselage. " Cyrano," though not without aerodynamic interest, is purely experimental—hence, presumably, the generous dihedral. The wings are backswept, 20 deg. on the leading edge, and 15 deg. on the trailing edge, the chord tapering from 7 in. to 5m. The tip-to-tip span is 38m., and the wing area approxi mately 230 sq. in. The fuselage is 3i£in. long, 6in. deep in the region of the wing, and 3^in. deep to the rear of the airscrew. A tailplane of lifting section is employed, the span being °in., and the chord tapering from s\m. to 3m. It is interest- >ng to learn that a rolling tendency experienced when the tail- plane was in line with the thrust-line completely disappeared when it was lowered to its present position. There is now no appreciable alteration in trim when the' power ceases. the all-up weight is noz. Flights of 45 sec. have repeatedly een obtained, which figure should be materially improved upon in a second edition. r^ S.M.A.E. Expansion. J HAT model aviation in Great Britain is on the up-grade Of thl% made abundan% clear at the annual general meeting at fh R 16ty °f Model Aeronautical Engineers, recently held yea™ y Aeronautical Society, Albemarle Street. Three ago, when the S.M.A.E. was reconstituted, there were "affiliated clubs now there are 92, representing a member- re^sterfv'55^- feWer than x*7 Petrol models have been under wV h u exPansion has led to the adoption of a scheme self-eovPr • country will be divided into areas, largely Council j/1?' and whose delegates will form the S.M.A.E. in g and T • alS0 mvo,ve<i the hon. secretary in the receiv- °utstandSWering °£ °Ver 2'°°° letters during the vear! Qing events of the year were, the recognition by the F.A.I, of records made by models, the win ning of the King Peter Cup by a British y/' team, and the establishing of 30 records, including Mr. R. Copland's world record of 33 min. 9 sec, which, it was announced, has been homologated' by the F.A.I. The following elections and re-elections of officers took place: President, Dr. A. P. Thurston, F.R.Ae.S., etc.; vicerpresidents, the Duke of Richmond and Gordon, Mrs. Thurston, Com. H. E. Perrin, M.B.E., Lt.-Col. J. T. C. Moore-Brabazon, M.C., M.P., Major C. E. Bowden, Capt. L. Plugge, M.P., F.R.Ae.S., and Messrs. W. E. Evans, C. R. Fairey, M.B.E., F.R.Ae.S., A. F. Houlberg, A.M.I.Ae.E., B. K. Johnson, D.I.C., F.R.M.S., Percival Marshall, C.I.M.E., J. Laurence Pritchard, and G. Geoffrey Smith M.B.E.; chair man, A. F. Houlberg; vice-chairman, L. J. Hawkins; hon. secretary, E. F. H. Cosh (who was also elected a Fellow in recognition of his services); hon. treasurer, L. J. Hawkins; competition secretary, J. C. Smith; Press secretary, H. York; technical secretary, Flt.-Lt. R. N. Bullock. Models on Show CONSIDERABLE diversity marked the model aircraft dis play at the Schoolboys' Exhibition, recently held at the Horticultural Hall, London. S.M.A.E. exhibits included Mr. Copland's world record holder; an exceptionally fine example of monocoque construction in the form of a glider by Mr. Pope; a twin-ruddered pusher biplane, with tail carried on two booms, by Mr. L. Mann; a shoulder-wing monocoque "Wakefield" model with three-bladed airscrew by Mr. H. \V. Beckett; a pusher seaplane by Mr. R. T. Parham; the Crow biplane described in Flight of December 8 last; a well-cowled petrol- engined high-wing cabin model by Mr. E. Keil; and the present writer's successful composite model—13m. mid-wing carried on a 26in. low-wing—with single-bladed airscrew. On another stand was a magnificent flying scale-model of the Miles Master trainer. Scale and Semi-scale T HE scarcity of flying scale-models, doubtless due to the scarcity of prototypes which lend themselves to the incor poration of sufficient stability to fly without a pilot, and to the meagre performance as compared with free-lance types, is regrettable, for a really good model of this class, such as the Htston Phoenix, Fokker Faucheur, Miles Master, and Airspeed Envoy produced by Mr. H. J. Towner, of Eastbourne, is a fascinating thing. One notes with interest that a flying scale contest, for which a Flight Trophy will be awarded, is again included in the pro gramme of the annual gala of the Northern Heights Model Flying Club, the seventh of which meetings takes place at Fairey's Great West Aerodrome on June 18. The "semi- scale '' type—free-lance designs approximating in appearance to full-scale—is again to be encouraged by the award of the handsome Coronation Cup. Design and workmanship will score as well as the average duration of three rise-off-ground flights. Full details may be obtained by sending 2d. in stamps to Mr. C. A. Rippon, 58, Hampden Way, London, N.14. * » » A return flight to Paris, presented by Imperial Airways, is one of the 50-odd prizes for this year's Skybird League Rally. There is also a prize for entrants from the R.A.F. Details from the Secretary, The Skybird League, 3, Aldermanbury, London, E.C.2. Skybird models are i/72nd-scale non-flying models.
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