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Aviation History
1925
1925 - 0022.PDF
JANUARY 8, 1925 SOCIETY OF MODEL AERONAUTICAL ENGINEERS Report on Research Competition IN the April 24 (1924) issue of FLIGHT particulars were given of a competition organised by the Research Committee of the S.M.A.E., in which it was stated that the committee was desirous of finding out, by the use of models, a means whereby the safety of flying by full-sized machines might be increased. The chief points aimed at were that " stalling " should be reduced to a minimum, and that in the event of a machine getting into a vertical dive after a stall, it should emerge from this dive in the shortest vertical distance possible. To this end the principal conditions of the competition were that the models were first to be tested to see that they were in gliding " trim," and then to be dropped vertically down- wards from a height between 20 and 30 ft., the winning model to be the one which recovered flying equilibrium in the least vertical distance without stalling afterwards. This com- petition was therefore duly carried out on the Sudbury Flying Ground on October 18, and fortunately ideal weather pre- vailed at the time. The necessary apparatus for dropping the models consisted menced the dropping apparatus was kept working at " full pressure " with competitors eagerly preparing their models for the " vertical dive." However, only six machines were eligible to compete, and all of_these passed the test of gliding by hand-launching : but when it came to dropping the models vertically downwards only one recovered flying equilibrium without stalling afterwards ; this was a modified " Dunne " type of model constructed by Mr. B. K. Johnson. This model got out of the vertical dive in approximately 10 ft. and then glided to earth steadily at a reasonably good angle. This performance was repeated again and again with exactly the same result each time, showing unquestionable consistency on each flight. The other competitors, Messrs. Tucker, Lansdawn, Sherwen, Green and Hersom, unfortunately (in the judge's words), " killed their pilots several times over " ! It must be mentioned, nevertheless, that Mr. Tucker's model made many praiseworthy attempts, but just failed to get out of the dive. Mr. B. K. Johnson was therefore awarded the Research Committee's prize, very generously FIG.I. RELEASING DEVICE FIG.2 FIG.3.B.K.JOHNSON'S "DUNNE'TTPE MODEL THE S.M.A.E. RESEARCH COMPETITION : Figs. 1 and 2, the method employed in launching the models. Fig. 3, details of the winning model constructed by B. K. Johnson. of two upright masts, suitably braced, with a releasing device (which could be pulled up and down) suspended mid- way between them at a height of 23 ft. from the ground. The construction of the releasing device will be gathered from Fig. 1. Two pieces of hard-rolled brass strip, A and B (bent to the shape shown), were mounted conveniently on the underside of a wooden board, G, to which the raising and lowering rope R was attached. To each side of A and B were soldered a piece of piano-wire, Px and P2, with a loop made at each extremity, through which a steel wire pin, D, passes. To this pin was attached a piece of string, S, which passes over the pulley E mounted on the top of the board The model is held in the jaws J, by first springing the brass strips apart, inserting the model, and then securing them together under pressure by putting the pin D in position. When the device has been pulled up level with the top of the masts, the string S is pulled and the model is released. The following is a brief account of the events of the com-, petition : Some twenty members of the S.M.A.E. were on the flying ground, and before the competition officially com- offered by Mr. W. E. Evans (their secretary!. The path o flight of Mr. Johnson's model, together with the apparatus used in the competition, are shown diagrammatically in Fig. 2 Plan and elevation views of the winning machine are given in Fig. 3, from which the general appearance will be seen. The familiar arrow-shaped wing (which was characteristic of the Dunne machine) was employed, but upturned extended wing tips were used in place of the increasing negative angle of incidence towards the tips as used on the Dunne. No tail or rudder was fitted to the model. The fuselage, triangular in section, was made from a central backbone of -&-in. square birch, round which the steel wire framework was built and then covered with Jap silk. The drawing of the wing is self-explanatory. The weight of the model was 4 ozs. (as stipulated by the rules), and had a loading of 4 ozs. persq. ft. . In conclusion, the performance put up by this model was so convincing that more experimental work is to be done to further exploit the possibilities of the Dunne machine, and to this end the Research Committee is engaged very actively, im . arranging further competitions on these lines. .... .. • '; . . The " Los Angeles " (Z.R3) to Make Another Big Flight THE U.S. rigid airship " Los Angeles " (Z.R.3), it is reported, will make a flight next spring to Bermuda, Porto Rico and the Canal Zone, and probably to Europe or Honolulu. Air Attacks in the Hedjaz IN the reports on the trouble now prevailing in the Hedjaz between King AH and Ibn Saud it is stated that the former's aeroplanes dropped what are described as. harmless bombs between Jeddah and Mecca. . : Czecho-Slovakia's D.H.50 THE D.H.50 biplane (Siddeley " Puma ") purchased by the Czecho-Slovakian Government has been flown to Prague by Capt. C. D. Bernard, who will probably inaugurate a new service with this machine between Prague, Vienna, andTrieste.
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