GB244813A - Improvements in or relating to aerofoils - Google Patents

Abstract

244,813. De Havilland Aircraft Co., Ltd., and Hagg, A. E. Sept. 15, 1924. Steering and balancing.-A device of the character described in Specification 219,388 wherein a movable marginal portion of a wing is elastically controlled to enable the camber or incidence of the wing to vary automatically with the air speed without interfering with the pilot's control over those portions, has a modulating device for ensuring that the force exerted by the elastic control upon the movable member decreases or is substantially constant as the member moves to reduce the camber or incidence. Fig. 4 shows a perspective view of a device mounted upon the wing framework for controlling a flap extending along the rear edge of the wing. The flap is connected by a rod 24 to a crank 23 mounted on a spindle 20 passing through one arm 18 of a bellcrank lever pivoted about a spindle 16 to a bracket on the wing. The lower end of the spindle 20 has an arm 21 connected by a link 22 to a double-armed lever 17, also pivoted about the spindle 16, and the ends of these arms are connected by cords 32 to a corresponding lever at the other side of the machine and to the pilot's control lever. The arms 23 on the two sides of the machine are arranged as described in Specification 184,317 in order that the movements of the flaps, when moved in opposite directions by the pilot, shall be unequal. The arm 18 is integral with a double armed lever 19 connected by crossed wires 34 to a similar lever on the opposite side of the machine so as to move in unison with it and by moving the spindles 20 effect equal movements of the flaps. The other arm 26 of the bell-crank lever is connected to a rod 27 acted upon by a compression spring in a cylinder 29, and the arm 26 is set at such an angle that the movement of the spring decreases as it is compressed by upward movement of the flap. Where the trailing marginal flap on each wing is divided into two parts, as shown at 36. 120, Fig. 5, only the outer parts 36 are movable by the pilot to act as ailerons, the inner flap 120 on each side of the machine being connected to the arm 138 of a three-armed lever, the other arms 119 of which are connected by links 39 to the ends of the levers 19. Specifications 15920/13 and 17034/13 also are referred to.