GB313415A - Improvements in or relating to the tail surfaces of aircraft - Google Patents

Abstract

313,415. Macmillan, N. Dec. 6, 1927. Steering and balancing - To prevent stalling in aeroplanes, slots are opered automatically or positively at the leading edge of the tail plane so as to reduce, balance, or over balance the effect of the elevator as the machine is forced to its critical angle. Thin planes d, mounted on parallel linkages, may be normally held against the upper surface of the leading edge of the tail plane by air pressure, but so arranged that as the critical angle is reached the junction between the planes is presented to the relative wind and the thin planes are raised to open slots. The thin planes may alternatively be moved positively by link connections to the elevator, or by the elevator controls, through a lost motion device permitting a predetermined range of movement of the elevator without affecting the thin planes. The thin planes are returned to their normal position, in these modifications, by springs. Fig. 5 shows a modification in which an auxiliary plane d is mounted on a fixed part of the fuselage to fit against a movable tail plane a so that a slot is formed as the forward end of the tail plane is depressed. Alternatively a plane d. Fig. 6, mounted on parallel links d<1> of which one has an extension d<3> is moved to open a slot when a stop o, on the cable for moving the tail plane, engages the extension d<3>. fig. 9 shows a modification in which a lever y for moving the plane d can be left free or locked in any relative position to an elevator control lever q so that the pilot can vary the angle at which the slot will open or leave the slot permanently closed at will.