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Aviation History
1948
1948 - 1632.PDF
4io FLIGHT SEPTEMBER 30TH, 1948 Actual p hy.sical mechanism of flap and aileron gear which is shown dia- grammatical ly in another drawing. Lettering of different surfaces is the same as on the large key drawing. The link- age is such that aileron angle is in- dependent of flap position. Another special feature of the flap system is the very simple mechanical arrangement of the aileron controls, which have to transmit motion from the body or fixed part of the aircraft into the movable flap, and to com- pensate for the rearward flap movement without dis- turbance to the aileron setting. This is achieved by mounting on the inner front flap supporting link a lever which pivots in the plane defined by the pivotal axis of the link. The control rod coming from the stick is co- incident with the upper or fixed pivotal axis of the link, and is attached to the lever by a universal coupling. Motion from the lower end of this lever, which is coincident with the movable pivotal axis, is transmitted to the aileron via High-Lift Research . . . ported on two shear links andone torque link at its inner end. The main and auxiliary flapshear links are coupled together so that the latter is auto-matically operated by movement . of the main flap. Although Vvthis arrangement necessitates the main flap being made tor-sionally stiff enough to carry its own load and those arising fromaileron movement, the net result is an actual saving in weightand a great simplification of operating mechanism. The linkage is arranged in such a manner that the flaps arelowered during a combined downward and rearward move- ment. Flap Operation The flaps are operated by screw jacks connected to thefront links. Motive power is provided by a standard accumulator and a i£ h.p. electric motor which drives twohigh-speed shafts "from a common central gear box. A bevel gear at each jacking point carries the drive io thescrew jacks. This method of operation ensures complete synchronization of port and starboard flap movement. Theenergy required to lower or raise the flaps is less than 0.5 amp hours. Any one of three flap positions, Up, Half(take-off) and Down, can be selected on a gate-type control on the instrument panel. Incidentally, the first flight wasmade with flaps locked in the take-off position. Adjustable limit switches, accessible through panels, are operated bythe port side flap torque arm. a pull-push rod which passes through a hollow journal in the flap supporting link. It may also be noted that the high-lift increment is achieved without recourse to extreme flap shapes. The lower leading edge of the flaps is square cut with the view to forming a clean aerofoil section when retracted. Tests show the loss of lift increment as compared with rounded leading edges is negligible. So far as they have gone up to the present, the flight tests of the Youngman wing appear to indicate that the problems associated with the retention of full lateral and longitudinal control in conjunction with full-span flaps have been solved. YOUNGMAN-BAYNES RESEARCH AIRCRAFT D.H. C»ipsy Queen 32 Engine* Span 33ftWing area 180 sq ft Wing loading 20 lb/sq ftChord thickness at root y 14 per centChord thickness at tip 12 per cent All-up weight 3,600 lb '^Flight " photograph!.^ The Youngman flaps in "up" and "down" positions. Note that the aileron is in neutral position in both cases, unaffected by flap angle. A photograph of the complete aircraft was published last week.
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