Dynon Avionics Servo Datasheet / Generic Servo Kit (Push-Pull) User Manual
Page 4
DYNON AVIONICS
Servo Mounting Instructions – Generic Push-Pull Kit
3
101046-000 Rev E
When cutting the push-pull rod to size, take into account the extra length provided by the
unthreaded portion of each rod end. The distance between the servo arm and the control system
attachment point must allow for the angle between the servo arm and the push rod to be at
approximately 90º when the controls are at neutral. With the measurements taken, cut the tube
down to the correct length and tap both ends to a depth of 1" using a plug type tap. Once the push-
pull rod has been cut and tapped, follow standard practices for threading both rod ends into the
tube with jam nuts installed. Thread the supplied AN315-4R jam nuts onto the rod ends. Screw at
least half of the threads on each rod end into the push rod. Adjust length as needed, and then
tighten jam nuts.
When using the generic mounting kit, we suggest first installing the linkage at the outer-most hole of
the servo arm. Changing this location will affect servo torque output, servo arm travel, control
surface resolution, and the amount of force required to shear the safety screw, and should only be
changed if the installer has an understanding of these implications. See the diagram on the following
page which illustrates the linear travel and available force for each mount point on the standard and
long-arm servos.
Standard mounting of the linkage to the servo arm will include the AN3H-10A bolt, AN970-3 large
diameter flat washer (for capturing the rod end bearing), 2 AN960-10 flat washers on each side of
the servo arm itself, and the AN365-1032A lock nut. If an alternate stack-up is required (which may
include a spacer trimmed from the supplied tubing), substitute the AN3H-10A with a longer bolt. It
is recommended that the rest of the stack-up remain the same, using the large diameter flat washer
as a safety device to capture the rod end bearing.
There will be a variety of methods used to install the other end of this control linkage to the existing
mechanicals of the aircraft. Some systems will use a bell crank that will need a hole drilled at an
appropriate location. Others will use an attachment to an existing linkage. Others may attach directly
to the control stick itself. It is up to the installer to decide which method is best in terms of safety
and autopilot functionality.
Installers should always keep in mind the range of motion of the servo. Total servo arm travel needs
to be limited to prevent an over center situation. Take this into account when selecting the
mounting location and linkage attachment point for any servo installation. The built-in control stops
of the aircraft will limit the servo arm travel when installed correctly. We recommend you use the
optional Range of Motion Limiting Bracket, supplied with the servo to eliminate the chance of the
servo arm going over-center. This bracket should not be used as a normal stop; the aircraft’s built-in
stops should always be the primary range limit.
Your servo(s) and AP74/76 (if ordered) came with a CD containing the latest documentation for all
Dynon products (also available a
Please read through that documentation to
understand the wiring and configuration process for your Autopilot system. We also maintain a
collaborative set of this documentation, which is often updated with new information by both
Dynon and fellow builders. Vis
to view and contribute to the latest
version of these documents.
You can also visit
to discuss and share installation notes, pictures, and
suggestions with other builders.
Neglecting to properly install and/or use Dynon autopilot hardware may result in failures
which could cause loss of aircraft control resulting in aircraft damage, personal injury or
death.