When the pilot moves the rudder pedals, the rudder pedal arms pivot on the rudder pedal pivot axis. Control rods transmit the movement of the rudder pedal arms to the jackshaft assemblies and the yaw control system.
The pilot also uses the rudder pedals to operate the wheel brakes. The pedals then rotate on their upper pivot axis.
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RUDDER CONTROL -PEDAL ASSEMBLY
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RUDDER CONTROL -JACKSHAFT ASSEMBLY
Purpose
The purpose of the jackshaft assemblies is to transmit rudder pedal movement to the left and right shaft assemblies. The bus rod connects the two sets of rudder pedals together. Command of the rudder pedals by one pilot results in the backdrive of the other set of rudder pedals.
The right jackshaft assembly also transmits the movement of the rudder pedals to the nose wheel steering system.
Both jackshaft assemblies have a rudder pedal adjustment. It permits the pilots to adjust the rudder pedals to the most comfortable position.
Jackshaft Assemblies
The jackshaft assemblies have a shaft on which a sleeve yoke slides. The two ends of the yoke attach to the control rods from the rudder pedals. The bus rod connects the two jackshaft assemblies together. A control rod connects each jackshaft assembly to the right and left shafts.
The left and right jackshaft assemblies are the same except for their shaft. The right shaft has a spline at the lower end. The nose wheel steering crank is on the spline. The crank connects to the nose wheel steering mechanism.
Rudder Pedal Adjustment
A rudder pedal adjustment crank is in front of each pilot.
The rudder pedal adjustment crank connects to a flexible cable drive. The flexible cable drive rotates the screw inside the jackshaft assembly. This causes the internal nut and the sleeve yoke to move fore and aft. The control rods connected to the yoke and the rudder pedals cause the rudder pedal arms to move one set of rudder pedals. The pilots adjust each set of rudder pedals independently of the other set without any input to the yaw control system.
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RUDDER CONTROL -JACKSHAFT ASSEMBLY
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RUDDER CONTROL -CONTROL AND BUS RODS
Purpose
The control and bus rods transmit movement from the rudder pedals to the yaw control.
The rods include:
*
Control rods between the rudder pedals and the jackshaft assemblies
*
A bus rod between the two jackshaft assemblies
*
Control rods between the jackshaft assemblies and the shaft assemblies.
Control Rods
Four identical control rods connect the rudder pedals to the sleeve yokes of the jackshaft assemblies. These rods have a one-way pogo. The pogo spring permits only compression of the rod. A force of 12 to 15 lb (5.4 to 6.8 kg) at the pedal causes a breakout. The length of these control rods is adjustable.
Two identical control rods connect the jackshaft assemblies to the crank of the shaft assemblies. The length of these control rods is adjustable.
Bus Rod
The bus rod connects the two jackshaft assemblies. The length of this bus rod is not adjustable.
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RUDDER CONTROL -CONTROL AND BUS RODS
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RUDDER CONTROL -FEEL AND CENTERING MECHANISM
Purpose
The rudder feel and centering mechanism supplies feel and centering forces to the yaw control system. The rudder trim actuator supplies rudder trim control. The rudder trim moves the neutral position of the rudder and the rudder pedals.
Physical Description
The feel and centering mechanism has a single cam and roller unit. The cam attaches by a spline to the left shaft assembly and turns with it. The follower assembly has a roller which rolls on the cam surface. An arm supports the follower assembly. The arm pivots on a lever bearing mounted on the left shaft assembly. The lever attaches to the trim actuator rod end. Two springs, between the lever and the arm of the follower assembly, keep the roller on the cam.
The rudder trim actuator attaches to the structure of the left shaft assembly. The rod end of the actuator connects to the lever of the feel and centering mechanism. The rudder trim position transducer also connects to the lever of the feel and centering mechanism.
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