GB524280A - Improvements in the control of aircraft - Google Patents

Abstract

524,280. Controlling aircraft. HASKIN, S. Jan. 25, 1939, No. 2627. [Class 4] A braking flap normally mounted substantially flush with the wing of an aircraft but movable at will at its leading edge away from the wing, has releasable means for holding the trailing edge of the flap to the wing so that the trailing edge can be released and allowed to trail in the wind to facilitate the return of the flap to its inoperative position. Fig. 6 shows a flap 12 mounted upon the upper surface of a wing by lazy-tongs linkages 20, 21 and a locating link 15, the flap being provided at its leading edge with a servo-flap 22. Normally the flaps lie flush with the plane but when the flap 22 is raised by means of cables 27 passing through a link 30, the leading edge of the flap rises, the rear lazy-tongs being prevented from expanding by a pilot-controlled device. To restore the parts to normal position the rear edge is released and the flap 22 is turned down. The cables 27 are controlled by a pedal, spring urged in a direction to lower the flap 22, and provided with a locking pawl. Alternatively the wing may be provided with a flap 41, Fig. 9, normally nested beneath the wing, the leading edge of the flap being positively raised and lowered by lazy-tongs linkage 42 controlled by the mechanism shown in Fig. 10, where a nut 50 turned by gearing 52, 53 acts on screws 48 to expand and contract the linkages. Similar mechanism may be used for actuating the linkages 43 supporting the rear edge of the flap 41, or the linkages 21 supporting the rear edge of the flap 12, Fig. 6, but preferably the screw and nut mechanism is replaced by a hydraulic cylinder having two pistons connected to the linkages, the fluid flow being controlled by a valve in such a manner that free movement is permitted in one position of the valve but in another position movement is prevented. By raising the leading edge of the flap 41 after locking the trailing edge in its lowered position, as shown in Fig. 9, additional lift is obtained.