Trio Avionics Pro Pilot - Manual (Page 73)

Trio Pro Pilot Manual 3.8
73
Chapter 18
The Servos
Servo Installation and Setup
The servo unit incorporates important safety features:
 The internal gears are pulled into the engaged position by an electric solenoid. When the gears
are not engaged, the output crank arm rotates freely and the aircraft controls can be operated
normally without friction. When the servo is engaged, the solenoid pulls the gears into place so
the servo positions the control surfaces. Disengaging the servo allows free movement of the
controls.
 The roll and pitch servos are engaged and disengaged by pressing H NAV and V NAV buttons
respectively. We also recommend installing a remote SERVO DISCONNECT switch on the
control stick (or other remote location). Installation of a remote switch (or dual switches) is highly
recommended, as it allows an immediate way to disengage the servos - even in heavy
turbulence, when it may be difficult to operate the individual H NAV or V NAV button. In addition,
such a switch(s) will allow for the PILOT COMMAND STEERING feature and the VS (vertical
speed) and AS (airspeed) capture features.
 The servos also employ a clutch, which allows the pilot to override the servos by applying
moderate force to the control stick. Even though the solenoid will hold the gears in place, the
clutch will then slip and allow the control surfaces to move. In the event of strong turbulence,
conflicting traffic or an altitude anomaly, the pilot can thus override the servos to control the
airplane. In such an instance, the servos should normally be disengaged as soon as possible.
NOTE: The clutch function does not rely on a shear pin failure mechanism as is employed on some
other popular autopilot servos. Activation of the “clutch” function in no way damages the servo
drive system although prolonged operation in this condition should be avoided.
Installing a Servo
Begin by looking for a point on your aircraft bell crank, control pushrod or cable where pushing or pulling
the aileron or elevator control linkage a distance of 1.5 to 2.4 inches will do the job. Then find a place to
mount the servo nearby to accomplish this by means of the pushrod.