FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1939
1939 - 0042.PDF
24 FLIGHT. JANUARY 5, 1939 . MODELS By M. R. KNIGHT An Easy-to-Build "Semi-Scale" THE biplane pictured here, a recent effort of the writer's, is a general-purpose type on "semi-scale" lines. One has frequently advocated this compromise between the more realistic appearance of the so-called scale model and the high performance of the free lance class, in which sheer practicality is the keynote, believing that such models would attract man - who regard the average machine of to-day as a toy. It is, however, the unusual wing construc tion which is the chief reason for the inclusion of the Kittihawk in our series of model de scriptions. This system, introduced to the writer by Mr. C. A. Rippon, offers simpler and speedier construction, particularly in the . case of tapered wings, since careful plotting and shaping of multitudinous pairs of ribs is obviated. One merely has to fix the maxi mum and minimum chords and spar depths and cut the spars carefully to size. The depth and positioning of the spars secures and author's maintains the camber. Reference to the photograph will reveal upper and lower ribs, which are formed from balsa strips jin. wide and ^jin. thick, placed face downward instead of on edge. The wing is built actually on a full-size drawing, the lower ribs first being fastened down between pins, their length being immaterial so long as it exceeds the chord. The spars are cemented on to them, and the upper ribs cemented over the spars, when the ribs are trimmed flush with the leading- and trailing-edge. Such a wing is very free from warping tenden cies, and quite light. Despite no fewer than 27 pairs of ribs in a 34m. wing-span, Kittihawk weighs 5J oz. The orthodox four-longeron fuselage calls for no comment, save that the " engine cowling " is thick celluloid, aluminium- painted bamboo struts, balsa-faired, carry each i£in. wheel, and plug into stout paper tubes securely cemented to the in terior of the fuselage. The tailplane is of lifting section. A. ioin. airscrew is shown, but longer and steadier flights have been obtained by increasing the diameter to 12m., this being turned by a single 8-strand of Jin. flat rubber. The wing-area is 210 sq. in., the chord 3fin.—3in!, the gap 3|in. and the dihedral angle 7 .deg. Looking Back—and Forward THE January Models Page seems a fitting place wherein to emulate old Janus, from whom the month takes its name, in looking back, and at the same time looking forward. The recalling of the peak performances of 1938 should prove the more interesting and instructive in that one is able to give the S.M.A.E. contest programme for 1939. I propose here to group all the events according to the class of model involved, and subsequently to repeat them in chronological order, deal ing with a month or two at a time. Since the Wakefield International Trophy is the piece de resistance of model aviation, let us first consider the 8 oz./ 190-210 sq. in. models stipulated for the Wakefield and sundry other contests. High-wing and shoulder-wing layouts are widely favoured, with opinion sharply divided on the respec tive merits of streamlined and slab-sided fuselages. Exponents of the latter claim that they behave better in a choppy wind, and that the virtues of streamlining are barely perceptible at the 15 m.p.h. of the Wakefield model. They are obviously more speedily built and replaced when lost. In 1938 America won the Wakefield Cup against 13 other nations with a constant-chord high-wing, having sharply dihedralled elliptical tips, an oval monocoque fuselage and a retracting single-bladed airscrew. The 1939 contest will there fore be in America, the British team of six being chosen in trials at Fairey's Great West aerodrome on May 28. Luck still plays a part in that even 8 oz. models are assisted by the fortuitous contacting of thermals. Technically, Great Britain has nothing to fear, despite considerable progress abroad. There will be a decentralised contest (one held on the grounds of clubs affiliated to the S.M.A.E.) for Wakefield-type models for the Weston Cup on April 16. Gliders will figure largely this year, through being stipulated in the contest for the trophy given by King Peter II, of Yugo slavia, which will be held between July 17 and 23. The British team will be chosen in trials on the same ground on May 29. Kittihawk, which embodies an interesting and simplified system of wing construction. Last year, when the cup was given and rubber-driven models were used, Great Britain won, thanks largely to Mr. R. A. Copland, whose shoulder-wing model achieved a world record (subject to F.A.I, recognition) of 33 min. 9 sec. Decentralised glider contests will be held on March 19 and May 7, for the Pilcher Cup and Model Engineer Cup No. 1, respectively. Petrol-models greatly advanced in numbers and quality dur ing 1938, and this year the following five trophies will be awarded for this type: C.S.S.A. Cup (decentralised) on March 19, Flight Cup at Cranwell aerodrome (by permission of Air Vice-Marshall J. E. A. Baldwin, C.B., D.S.O., O.B.E.) on June 11, Hamley Trophy at Heath Row on July 2, and Sir John Shelley Cup and Bowden International Trophy at Heath Row on August 7. The Seaplane Tank Triumphs THE portable canvas launching tank for seaplanes, originated by T.M.A.C. several years ago, receives full official recognition by being specified for the Lady Shelley Cup and White Cup contests (the latter for flying boats only) at Heath Row on June 25. In the decentralised contest for Short Brothers Cup on May 21, tanks are optional. The tank device has removed two big obstacles to seaplane popularity and progress, viz., scarcity of open spaces containing ponds with shelving sides, and risk of waterlogging through overturn ing when taking-ofl or in alighting downwind. Biplanes, which have won a considerable, though tardy, popularity, will be catered for in a decentralised contest for the Kite and Model Aeroplane Association Cup on September 3rd. Last year there were 70 entries. The British seaplane record of 6 min. 54 sec. is held by a biplane ! The F.R.O.G. Cups, senior and junior, are offered for the "semi-scale" class of model, trials taking place on May 7, and the contest proper at Heath Row on August C. The in augural contests last year—for day bombers—produced a small but technically meritorious entry. Revised rules may raise the number of entrants. There are three contests for duration, irrespective of weight or wing area, the Gamage Cup (decentralised) on April 2, the National Cup at Heath Row on August 6, and the Farrow Shield (team, inter-club) decentralised, on September 17, also a Woman's Cup contest at Heath Row on August 6, and a speed contest for the Model Engineer Cup No. 2 (at a venue to be decided later) on September 24. Air Defence Cadet Corps Nearly 4,000 Strong THE Air League of the British Empire announces that the Air Defence Cadet Corps has achieved an establishment of 3,900 since the first squadron of ioo cadets was established in July. This figure has been reached by the formation of two new Squadrons, No. 38, Perth and district, and No. 39, Richmond and Barnes. The Duke of Atholl is president of the management com mittee of No. 38 Squadron, and Lord Provost Nimmo, chairman.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
