GB470528A - Improvements in aircraft - Google Patents

Abstract

470,528. Modifying the aerodynamic characteristics of aerofoils. BUDIG, F. June 25, 1936, No. 17633. [Class 4] An aircraft wing has a step of adjustable depth disposed on its under surface a short distance only from its leading edge and substantially in the plane of separation of the two fluid streams passing over the top and bottom surface of the wing, Fig. 4, and tapering away to the apex of the leading edge. A nested flap 6, Fig. 3, is pivotally mounted at a point 5 which lies at or adjacent to the point at which the positive pressure curve in the lower surface meets the negative pressure curve on the leading edge and upper surface when the aerofoil is at 20‹ incidence. Flap 6 is operated by a lever 7 connected by a link 9 to a fore and aft rocking lever 8 of which the rear end is adapted to engage a lever 14 fixed to a flap 12. Lever 8 is urged into the flap closed position by a spring 11 and in arrangement is such that flap 12 is allowed limited movement in either direction without causing movement of flap 6. Means may be provided for intermittently producing a flow of air through flap 12 to dissipate eddies formed on its upper sides. In one form, Fig. 5, this comprises a rotary valve 15 disposed in a through passage 16 and operated by power means and in another form, Fig. 6, passage 16 is opened and closed by a spring-loaded flap valve 17 actuated by air impulses fed into port 19.