GB718435A - Improvements in aeroplane control organs - Google Patents

Abstract

718,435. Aeroplane wings and naps. SHORT BROS., & HARLAND, Ltd. Sept. 9, 1952 [Sept. 28, 1951], No. 22680/51. Class 4 An aerofoil with a flap pivoted thereon comprises a cavity within the member it is desired to influence (aerofoil or flap) and a blade-like member pivoted within the cavity, dividing it into upper and lower compartments, communicating with the atmosphere on the upper and lower sides of the flap, so that angular deflection of the flap causes a pressure difference on the two sides of the blade like member, thus developing a turning moment on the member it is desired to influence. In Figs. 1 and 2, the member 11 is to be influenced, being pivoted at 12 on brackets 13 extending from the wing 10 into a cavity 14 in the flap 11. Also pivoted to brackets 13 is a blade 17 anchored to the flap at 18, and sealed at its leading edge by a strip 19 to a concave face 101 of the wing. The trailing edge of the blade may also be so sealed. Deflection of the flap, as in Fig. 2, causes differences in pressure on upper and lower flap surfaces, which differences are transmitted through slots 15 to the compartments A and B into which the blade 17 divides the cavity. These pressure differences exert a moment on the flap tending to counteract the restoring force exerted by the airstream on the flap. In an alternative embodiment, Figs. 3 and 4 (not shown) the cavity is wholly within the flap. In Fig. 5, the wing 10 is pivoted on a spar 20, and a forward cavity 21 is divided by a blade 26 pivoted on brackets attached to the spar. The compartments C and D communicate with the atmosphere by slots 151, 152, and pressure differences due to deflection of the flap I are transmitted to compartments C and D to exert a turning moment on the aerofoil about spar 20, tending to alter its angle of incidence, so that downward deflection of the flap makes the incidence of the wing decrease or become negative.