Control system and method for a semi-levered landing gear for an aircraft

A control system for controlling a tiltable truck of a main landing gear of an aircraft so that the main landing gear can function as a semi-levered gear during certain prescribed conditions, the truck including a bogie beam supporting wheels at forward and aft positions thereof, the landing gear including a main strut a lower end of which is pivotally connected to the bogie beam at a main pivot, the control system comprising:

• an auxiliary strut comprising a hydraulic cylinder connected between the bogie beam and the main strut, the auxiliary strut being connected to the bogie beam at a location spaced along the bogie beam from the main pivot, the auxiliary strut being operable to lock up upon receipt of a lock-up command signal such that a length of the auxiliary strut is fixed at a predetermined length;
• a ground mode system operably connected with the aircraft for detecting and providing signals indicative of when the aircraft is on the ground;
• a takeoff mode system operably connected with the aircraft for detecting and providing signals indicative of when the aircraft is operating in a throttled-up takeoff mode;
• and
• an auxiliary strut control unit operably connected with the ground mode system, takeoff mode system, and auxiliary strut, the auxiliary strut control unit being operable to issue a lock-up command signal to the auxiliary strut upon detecting signals from the ground mode and takeoff mode systems indicating that the aircraft is on the ground and that the aircraft is operating in a throttled-up takeoff mode, whereby the auxiliary strut is caused to lock up during a takeoff roll but is unlocked during other operating modes of the aircraft.