Trio Avionics EZ Pilot - v 1.9 - Manual (Page 32)

28
small that it takes very little slop in the system to make the airplane not track
properly.
It will simplify installation adjustments if there is enough overhead clearance to allow
removal and replacement of the servo lid with the servo remaining in place (for instance,
you will possibly want to adjust the slip clutch). The servo lid is secured by four screws at
the side of the box. But, if it is more convenient, the lid may be secured through holes in
the top of the lid with #4-40 machine screws.
7.4 Install the Servo Pushrod
Cut the pushrod to the proper length so that, when the servo is at neutral, the ailerons
are also neutral (see Note). Don’t worry about being exactly correct – the servo neutral
position will later be positioned (on the ground and in flight) using the electronics in the
EZ Pilot control head.
Choose the longest possible crank arm radius that accommodates a pushrod range of
movement equal to or exceeding that required for full aileron travel. Be sure that the
rod end bearings never jam due to misalignment as the pushrod angle is varied by
different combinations of control system input. Put the control stick (or control
wheel) in all four corners to test this.
7.5 Setting Servo Override Force (Slip Clutch)
The servo Torque Control nut (the locknut inside the servo on the output shaft) sets the
override force - the force you will feel at the stick when the servo clutch begins to slip.
Engage the servo by pressing the SERVO button on the control head. You should hear
the solenoid operate inside the servo housing and the servo crank arm should become
firmly held in place by the gear train. Then push the control stick hard enough to override
the servo. Set the override force to a value that seems strong enough to give a fairly
good roll authority, but not so strong as to be difficult to override with the control stick.
Work toward setting the servo slip clutch to the minimum torque necessary to give
enough roll authority to handle a reasonable amount of turbulence.
Slip Clutch Adjustment
Note: The neutral position for your ailerons will be dependent upon how precisely your flying
surfaces are aligned. In many homebuilt airplanes, the ailerons must be trimmed for proper (hands
off) straight and level flight. It is important to test fly your airplane prior to installing the servo to
accurately judge the position of your ailerons in trimmed level flight. Remember this position – it is
the neutral position for your ailerons