Trio Avionics Pro Pilot - Manual (Page 75)

Trio Pro Pilot Manual 3.8
75
Note: The controls must travel from control stop to control stop within the range of
movement allowed by the servo stops which limit crank arm rotation.
When the above conditions are met, the system usually performs best when the
pushrod is attached to the outermost hole in the servo crank arm. If your aircraft
employs a control system bell crank, you should ideally attach the pushrod to the bell
crank at a distance from its pivot point that allows full control system travel along with
maximum travel of the crank arm without contacting the servo mechanical stops.
Never allow the servo to limit aircraft control travel
outermost hole. In the event the servo rotation is insufficient, the servo mechanical stops may be
removed. Contact Trio Avionics if this appears to be necessary.
Servo Mounting Hardware
The following picture shows the electrical and mechanical installation kit that is provided for the servos.
A pushrod is provided for each servo, along with two rod end bearings. Typically, one of these connects
to the servo crank arm and the other is connected to the aileron or elevator bell crank. When the servo is
connected to the control system it should be installed so that the servo crank arm is at a right angle to
the control rod. This mechanically centers the servo mechanism to the control system so that there is
equal displacement in either direction when the servo is actuated.
Selecting a Site for the Servo
For most aircraft, it’s relatively easy to find a
suitable site for locating the crank arm servo.
The length of the pushrod and the angle it
makes with the driven element are user
selectable.
The rod end bearing allows some misalignment,
typically about 8 degrees, between the servo
pushrod and the plane of rotation of the crank
arm. This limit on angular displacement often
determines the minimum pushrod length. Any
side-to-side movement must not jam the rod end
bearing. A suitable hard point must be found, or
built, for mounting the servo. The mounting
place needs to be as accessible as possible,
and there must be a means of linking to the
control system. (The photo above shows an elevator servo installation in a RV-6).