GB559752A - Improvements in or relating to control surfaces for aircraft - Google Patents

Abstract

559,752. Aircraft control surfaces. WESTLAND AIRCRAFT, Ltd., and PETTER, W. E. W. Aug. 27, 1942, No. 12090. [Class 4] In order to vary the hinge moment of an aircraft control surface, means are provided for altering its thickness. particularly at that part of it to the rear of the hinge, either as a final adjustment while on the ground, or by the pilot during flight or as a consequence of the control surface being moved from its mean position. Fig. 1. shows an elevator pivoted at e and having a main spar supporting tubular ribs c connected together at their trailing edges. The ribs can be bent outwards as shown by a right and left hand screw-bolt h having a pinion i actuated by a light rack j or by insertion through the elevator of an adjusting rod. Alternatively a light cable may actuate several of such screws. In another form the ribs are adjusted by. toggle links actuated by a rod and turnbuckle, and the links themselves may be adjustable in length to give a different range of adjustment to the upper and lower surfaces. Fig 4 shows an aileron in which the ribs are connected by links r, t to two-armed levers p mounted on a shaft o extending through the aileron. The outer end of this shaft is pinned to a lever u extending to a point forward of the hinge e where it is guided in a slot. Upward deflection of the aileron causes the ribs to bulge,outwardly and downward deflection causes them to be pulled inwardly. An opposite effect is produced either by reversing the.position of the links r, t or by guiding the forward end of the lever u in a slot to the rear of the hinge e. The two arms of the lever p may be of different lengths. Either the upper or the lower link may be omitted in which case one surface remains unaltered. Fig. 5 shows another form in which the ribs have slotted plates v engaged by pins u on a guided tube x, the forward end of the tube having a roller 2 engaging a cam z shaped to give the desired variation of contour to the surface as it is deflected. The device may be used in conjunction with a horn balance and a tab control. Specification 448,249 is referred to as an example of a wing having variable camber, and Specification 346,251 as an example of a wing with flexible rear portion to change the camber automatically.