B. Rudder pedal input or rudder trim input causes the torque tube and cranks to rotate. This provides input to the rudder power unit, the feel and centering unit, and the standby actuator.
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526 Rudder Aft Control Quadrant and Torque Tube
Aug 15/69 Figure 2 27-21-0
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7. Rudder Trim Control Mechanism
A. The rudder trim control mechanism provides a means for controlling the directional trim of the airplane and indicates the units of rudder trim. (See figure 3.) The control mechanism consists of a rudder trim knob and indicator on the aft end of the control stand, and a cable drum attached to the knob through a vertical shaft.
B. Movement of the trim knob rotates the shaft and drum, which is connected by cables to the rudder trim actuator. Rotation of the knob moves the indicator a proportionate amount on the indicator scale. Maximum rudder trim travel is 12° in both directions. The indicator scale corresponds by being divided in 10 divisions in both directions.
8. Rudder Trim Actuator
A. The rudder trim actuator converts cable motion into a linear force which is applied to the rudder centering and feel mechanism. The actuator assembly consists of a cable drum and jackscrew nut, actuator housing, screw, compression spring and spring guide. (See figure 3.) The actuator compression spring produces a tension force between the nut and screw to prevent backlash. The jackscrew end of the actuator is attached to fin structure and the actuator housing is connected to the centering and feel mechanism. The jackscrew has a vernier plug for length adjustment.
B. Rotation of the cable drum causes the drum-and-nut and actuator housing to move linearly on the screw. Jackscrew nut forces are transferred to the actuator housing through a thrust bearing. Movement of the actuator housing causes the centering spring and feel assembly to rotate.
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526 Rudder Trim and Feel System
Aug 15/69 Figure 3 (Sheet 1) 27-21-0
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Rudder Trim and Feel System 526
27-21-0 Figure 3 (Sheet 2) Aug 15/69
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526 Rudder Trim and Feel System
Aug 15/69 Figure 3 (Sheet 3) 27-21-0
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9.
Deleted
10.
Rudder Feel and Centering Mechanism (Fig. 4)
A. The rudder feel and centering mechanism consists of the feel and centering unit which provides artificial feel to the pilots' pedals and centers the rudder. The feel and centering unit is located below the rudder power unit in the vertical fin (Fig. 3). The feel and centering unit has the following parts: A support shaft, a feel and centering crank, two frames, an arm and roller with a spring assembly, and a cam. The support shaft is bearing mounted on structure. The feel and centering crank is fixed to the support shaft and is connected through the trim and feel rod to the lower crank on the torque tube. The two frames are bearing mounted on the support shaft. The arm and roller and the spring assembly attach to and rotate with the two frames. The cam is fixed to and rotates with the support shaft. The cable drum end of the rudder trim actuator is supported by the forward side of the two frames. When the rudder pedals are displaced, the torque tube rotates causing offset of the trim and feel rod and in turn rotation of the feel and centering crank, the support shaft and the cam. As the cam rotates, the arm and roller are displaced out of the detent position to extend the spring assembly and provide artificial feel. Rudder trim input through the rudder trim actuator rotates the two frames with the arm and roller and spring assembly. The force of the spring assembly holds the arm and roller in the cam detent and causes the cam to rotate also. Rotation of cam causes subsequent motion of the support shaft, the feel and centering crank, the trim and feel rod, the lower crank, the torque tube which then causes input to the rudder power unit repositioning the rudder. At the same time the lower crank causes input to the rudder control system with movement of the pilots' pedals. 中國航空網 www.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：737 AMM 飛機維護手冊 飛行操縱 FLIGHT CONTROLS 1(100)
