LANDING GEAR

摘要

A semi-levered landing gear for an aircraft comprises a main shock absorber strut (1) connected to the airframe; a bogie beam (4) extending fore and aft of the airframe with forward and aft wheels (J, T) and a main pivot connection (5) to the strut (1) between the forward and aft wheels (7, T) and an auxiliary actuator (49) connected between the strut (1) and the front of the bogie beam (4) at an auxiliary pivot (14). The auxiliary actuator (49) comprises a two stage telescopic hydraulic unit comprising a first stage piston and cylinder actuator (59, 63) and a second stage piston and cylinder actuator (56, 50) operating coaxially within an outer casing (50). A respective piston rod (65, 60) each extends from each end of the casing (50) and is connected to a respective one of said (strut 1) and bogie beam (4). The first stage actuator (59, 63) is operable to an extended position, and the second stage actuator (56, 60) is operable between a retracted position (Fig. 11) and an extended position (Fig. 12) defined by respective end stops (75, 77) within the outer casing (50) and serves to control the tilt position of the bogie beam (4) relative to the strut (1). The second stage actuator (56, 60), when in the retracted position with the first stage actuator (59, 63) in the extended position, limits the length of the auxiliary actuator (9) between its connections (62, 67) to the strut (1) and bogie beam (4), so as to assume a predetermined intermediate length in which the bogie beam (4) is restrained to tilt about the auxiliary pivot (14) and thereby lengthens the landing gear during take-off. The second stage actuator (56, 60), when in the extended position with the first stage actuator (59, 63) in the extended position, allows the length of the auxiliary actuator (49) to assume a predetermined maximum length in which the bogie beam (4) is tilted about the main pivot (5) to a stowing position for stowing the landing gear in the aircraft.