The Boeing Company

Steven M Warren

Jerome R Kilner

Eugene T Raymond

Tubular members (22, 24) define a pressure chamber (26) and a reserve chamber (28) between them. A first variable metered hydraulic orifice area is provided between chambers (26, 28) by openings (32) in a metering tube (30). A second metered hydraulic orifice area is provided by fixed orifice (94). In a first mode of operation, both such areas are open during an initial retraction of members (22, 24). Control tube (34) is coaxial with metering tube (30) and has openings (36). In the first mode, latch (62) locks tubes (30, 34) together with openings (32, 36) aligned. Relative extension of members (22, 24) following the initial retraction causes pressure in chamber (28) to rise above pressure in chamber (26) and latch (62) to release control tube (34). Spring (40) moves tube (34) into a closed position in which it blocks openings (32). Shock absorber (20) then operates in its second mode in which fixed orifice (94) remains open and openings (32) remain closed. Relief valve (96) relieves excessive pressure buildup in chamber (26) in the second mode. Subsequent full extension of members (22, 24) automatically resets shock absorber (20) for operation in its first mode.

Dual mode shock absorber and method

Two-fluid nonflammable hydraulic system

A control system for maintaining an aircraft within the lateral boundaries of a runway during landing rollout under conditions of combined crosswind and low runway friction is disclosed. An automatic mode of operation is provided wherein the system utilizes an input signal representative of the heading of the runway being utilized and signals provided by (or derivable from ) an inertial navigation system to exercise coordinated control of the aircraft rudder, steering and differential braking system. In a semiautomatic mode of operation, signals supplied by the inertial navigation system (or its equipment) are utilized in conjunction with a continuous command signal that is provided by the pilot to indicate the desired aircraft trajectory. An optional provision is included for limiting the aircraft ground velocity slip angle to a range wherein an increase in ground velocity slip angle results in increased lateral corrective force on the aircraft. An additional optional provision modifies operation of the brake-antiskid system employed by the aircraft so as to reduce braking pressure by an amount that substantially optimizes lateral corrective force on the aircraft.

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Seattle, WA, United States of America

Steven M Warren