時間：2011-03-11 23:18來源：藍天飛行翻譯 作者：航空 點擊：次
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servo (automatic pilot component). A component in an automatic flight control system that actually moves the flight control. There are servos in each of the primary controls: the ailerons, elevators, and rudder. The automatic pilot senses when a flight correction is needed, and it sends a signal to the servo to move the control surface in the proper direction to make the correction. servo altimeter. A type of pneumatic altimeter in which the bellows moves an electrical pickup whose signal is amplified enough for it to drive a servo motor. The servo motor moves the drums and pointer in the display. servo amplifier. An electronic amplifier in an autopilot system that increases the signal from the autopilot enough that it can operate the servos that move the control surfaces. servo brake. A type of wheel brake that uses the momentum of the aircraft to increase the friction applied by the brake. The brake drum is a hollow cylinder, turned by the wheel that rides over the brake shoes. Brake linings, made of a material with a high coefficient of friction, are bonded to the surface of steel brake shoes and are pressed against the inside of the drum by the piston in a hydraulic brake cylinder. When the brakes are not being applied, a spring holds the shoes away from the drum. When the pilot depresses the brake pedal, hydraulic fluid forces the piston out and moves the shoe against the drum. The shoe is mounted in such a way that when it contacts the rotating drum, friction wedges it tightly against the drum. Movement of the aircraft increases the friction produced by the brake. servo feedback. A type of automatic control system in which part of the output is fed back into the input to help control the action. In an automatic pilot system, an attitude sensor detects a wing dropping and generates an error signal that causes the servo to move the aileron down. A servo feedback signal is sent from the aileron to the attitude sensor, indicating that corrective action is being taken. The attitude sensor progressively cancels its error signal as the deflected aileron brings the wings back to a level attitude. By the time the wings are level, the error signal is eliminated and the aileron is no longer deflected. servomechanism. A type of control system in which a small signal or small force is used to control a much larger force. In a hydraulic servomechanism, a sensor detects that some type of output movement is needed. A control valve directs hydraulic fluid into a hydraulic actuator, and the movement takes place. A feedback sensor compares the amount the actuator moves with the amount of movement the original sensor called for, and when the actuator has moved the correct amount, the selector valve is shut off. servo tab (aircraft controls). A small movable tab built into the trailing edge of an aircraft primary control surface. A servo tab is actuated by the cockpit control, and it moves in the direction opposite to the direction the primary surface is to move. The servo tab produces an aerodynamic force that moves the surface on which it is mounted. |
