GB564408A - Improvements in means for actuating aircraft control surfaces - Google Patents

Abstract

564,408. Controlling aircraft. PHILLIPS & POWIS AIRCRAFT, Ltd., and, MILES, G. H. Dec. 30, 1941, No. 16806. [Class 4] An turcraft control surface is fitted with a servo-tab acted upon by an inertia device to cause the tab to exercise a force upon the control surface in a direction tending to reduce any excessive displacement effected by the pilot. In one form, an elevator 5, Fig. 2, directly operable by a lever 8 is provided with a tab 9 connected by links 11, 12 to a bell-crank lever 14 carrying a weight 16. Normally, the lever 14 is maintained in a central position by spring- loaded arms 17, 18 and the joint 13 between the links 11, 12 is coaxial with the elevator pivot, but should the acceleration resulting from a movement of the elevator exceed a predetermined limit, the tab 9 is moved in a direction to reduce the angular displacement of the elevator. Fig. 3 shows another form in which the elevator 5 is controlled by the pilot solely through the servo tab 9 for which purpose it is connected by a link 23 to a spindle 27 connecting two levers 28 pivoted at 26 on opposite sides of a member 25 on the end of a pilot-operated jack 24. The levers 28 carry weights 29 and are biassed into the position shown by springs. Excessive acceleration results in the levers 28 swinging about the pivot 26 and altering the distance between 'the end of the link 23 and the jack 24. The link 23 and an arm 22 on the tab 9 are enclosed in fairings 30, 31. The device may be applied to ailerons, rudders or flaps in addition to elevators. Specification 468,062 is referred to.