Trio Avionics EZ Altitude Control - Manual (Page 16)

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The control movements are so 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 two screws on
the top of the servo.
6.4 Install the Servo Pushrod
Cut the pushrod to the proper length so that, when the servo is at neutral, or centered in
its full rotation stop to stop, the elevator is also neutral (see note).
Choose the longest possible crank arm radius that accommodates a pushrod range of
movement equal to or exceeding that required for full elevator 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.
When attaching the servo pushrod to an elevator bell crank, it is important to keep the
two lever arms equal. Measure the distance from the servo crank arm pivot point to the
outermost hole in the crank arm. Then drill an attach point in the elevator bell crank that
is the same distance from its pivot point. This will assure proper servo operation.
6.5 Setting Servo Override Force (Slip Clutch)
t
Note: The crank arm neutral position for your elevator control system will be dependent on
the particular aircraft design. Many designs require more throw of the control system from the
neutral elevator position to the full stick back position (elevator up) than the other direction.
In this case when the elevators are positioned at their neutral position , the crank arm will not
be at it’s centered (exact vertical or horizontal) position. This is not of concern during
operation of the system as the servo design compensates for this offset automatically during
operation. Again, the important thing to remember is that the elevator control system must
contact its mechanical stops before the servo contacts it’s mechanical stops