GB664548A - Improvements in or relating to bogie undercarriages for aircraft - Google Patents

Abstract

664,548. Undercarriages. BRITISH MESSIER, Ltd. April 3, 1950 [April 19, 1949], No. 10391/49. Class 4. An aircraft undercarriage incorporating a pivoted bogie frame comprises a jack, cylinder and piston connected between the undercarriage frame and, a point on the bogie spaced from the pivotal connection thereof to the frame for applying torque to the bogie opposing that set up upon application of the landing wheel brakes. As shown in Fig. 1 a combined oleo-pneumatic shock-absorber and jack is mounted between the bogie 14 and a lug 29 carried by the undercarriage leg, a pipe 35 connecting the brake system with the space behind the movable piston 34 of the shock-absorber. Upon application of the brakes the piston 34 is moved to compress the air in the space 33 of the shockabsorber and thus force the jack piston 26 out of its cylinder and apply an opposing torque to the bogie. In the embodiment according to Fig. 2 the brake pressure supply pipe 57 communicates with a combined oleo-pneumatic shock-absorber and jack 40 through relays 70, 90 and a pipe 51. The latter is connected to a space between the piston rod 41 and the cylinder of the jack, so that the jack extends upon application of the brakes. The piston rod 41 is hollow and contains a piston 47 attached to a further hollow rod 48 connected to a pipe 49 in communication with the undercarriage retraction control mechanism, so that the length of the jack is altered during retraction in order to ensure the necessary tilting of the bogie in relation to the undercarriage leg for stowage purposes. Alternatively the shock-absorber and jack may be separate, the brake pressure liquid being supplied only to the jack, which is fitted with relief valves to allow its rapid yielding in the event of the bogie moving over uneven ground.