GB489853A - Improvements relating to aerofoils - Google Patents

Abstract

489,853. Aircraft wing-flaps. MILES, F. G. Feb. 3, 1937, Nos. 3229 and 34147. [Class 4] An aircraft wing is provided with two flaps normally nested one above the other, each flap being adapted for alteration of angle of incidence relative to the main wing and at least one being supported on travelling mechanism adapted to displace it rearwardly relative to the main wing and to the other flap. In one form, Fig. 6, a split flap 3 is pivotally mounted at 2 below an extension flap 5 which is carried by mechanism comprising a hydraulic or screw jack of which the plunger 6 carries a pivot 7 for a lever 8 rigid with flap 5. To the end of plunger 6 is pivoted one of a pair of toggle links 9, 10 of which the other is pivoted to flap 5. The centre pivot 11 of the links is connected to a cable 12 passing through a fixed eye 13 in the wing and provided with a stop 12A such that after a certain rearward travel of the flap the cable is held to cause the toggle links to open and move the flap downward. A spring 14 serves to take up slack in the cable in the nested position of the flap. Spring means may be used to return the flap to neutral on the return stroke. The control mechanism of flap 3 may be so interconnected with that of flap 5 or may be such that the flap moves slightly downward when flap 5 is operated, in order to give the latter free passage. Plunger 6 may carry cam means serving to depress flap 3 and may be guided in rollers. In a modification, Fig. 8, the flaps are extended by lazy-tongs linkage having upper pivots 20, lower pivots 21, and intermediate pivots 22 disposed nearer to the lower than to the upper pivots so that rearward movement of the aftermost links is accompanied by downward movement. Various curved paths may be obtained by asymmetrical arrangement of these pivots. Links 23A, 23B carry pivot pins 23C, 23D. A flap 24 is pivoted on pin 23C and is formed with a cam slot 24A engaged by pin 23D. A second flap 25 which is adapted to nest below flap 24 is similarly mounted on links 23E, 23F. Extension of the linkage is by jack means of which the centre line is shown at 26. When fully extended the chord of the first flap is at an angle of 18¢‹ to the chord of the wing and that of the second flap is at 22‹ to that of the first.