GB595299A - Improvements relating to the arrangement and operation of control surfaces of aircraft - Google Patents

Abstract

595,299. Controlling aircraft. ARM. STRONG WHITWORTH AIRCRAFT, Ltd.. Sir W. G., and WATSON, H. R. Feb. 25, 1944, No. 3505. [Class 4] In order to minimise the effect on the pilot's control member of variations in the angle of incidence due to air currents, &c., a control surface carrying a tab is arranged in combination with a flap which is free to respond to changes in incidence and which carries a " geared tab to accentuate its response to such changes, the flap being connected to actuate a tab on the control surface as an incidence balance tab, the connection also serving to render the latter tab a " geared " tab, at constant angle of incidence, giving servo operation of the control surface when movement thereof is initiated by the pilot. The embodiment illustrated shows the invention as applied to a tailless aircraft. The elevator or other main control surface 12, operable by a link 23, carries a tab 13 which is connected by a link 20 to a short flap 14, also provided with a tab 15 operable through a link 17 having its end connected to a normally fixed member 18 on the wing. An increase of positive incidence results in the flap 14 being moved upwardly, its movement being accentuated by the downward movement of the tab 15 due to its connection to the link 17, with consequent upward movement of the tab 13 resulting in the main control surface being held against the upward lift due to increased incidence. Movement of the control link 23 enables the tab 13 to function as a balance tab, while trimming may be effected by adjustment of the member 18. The linkage may be such that the main control surf'ace moves downwardly against the wind as the angle of incidence increases.