TruTrak GX Pilot - Manual (Page 6)

TruTrak Flight Systems 3 GX Pilot Installation/User Manual
March 2011 Rev B
GX Pilot Series Ground Checkout
Must be performed before first flight
The check-out procedure is to verify that the servos run and in the correct direction. Once the track and altitude selections are
returned to current both the pitch and roll servos should stop, or move only very slowly.
If the direction of movement of the pitch servo is incorrect, install or remove the jumper between pins 1 and 2 of the autopilot
connector and repeat the setup to verify correct results up to this point.
The roll servo should also be responding at this time, moving the controls in such a way as to turn the aircraft from the current
heading. If the selected heading is right of the current heading, the control yoke or stick should move to roll the aircraft to the
right. Conversely, a selected heading to the left of the current heading will move the controls in the opposite direction to
attempt a roll towards the left. If servo direction is not correct, the wires going to pins 4 and 5 of the roll servo (pins 20 and 21
on the main connector) must be reversed to achieve the correct response. If a servo does not move at all, double-check the
torque voltage on pin six (6) of the servo. If a servo jitters but does not actually rotate, check the wiring on the four servo drive
lines to that servo for continuity and correctness. If the servo does not seem to have any torque, check the relevant torque
control line for continuity and correctness.
At this time, check that each servo arm or capstan is properly operating the controls. For servo installations using an arm, check
that as the controls go from limit to limit the arm of the servo remains in the operating range of the servo (a maximum of 100
degrees total rotation) and that when the controls are centered, the connecting pushrod is approximately perpendicular to the
arm of the servo. For capstan systems, insure that the cabling remains at proper tension and is properly secured as the servo
moves the controls from stop to stop. Insure that each servo remains secure in its mounting and does not flex its mounting
bracket as it drives the control to its stops. For installations using an arm, insure that as the servo moves the control towards the
end of control travel it does not cause the main control’s torque tube or push-pull tube to flex in any way that could cause
control system lockup at the extremes of servo travel. Insure that any “lost motion” in the linkages is eliminated or minimized,
in order to maximize the performance of the autopilot. Lost motion (dead zone) will result in wandering or slow “hunting”
behavior in flight.
GX Pilot First Flight
The factory default settings for the autopilot will not work for every aircraft type, but in most cases are good points from which
to start. A brief description of each setting is given below, beginning with the lateral setup menu. To access the lateral setup
menu, press and hold the AP button.
-LAT ACTIVITY- Increase this number to cure a slow wandering across track, decrease it to cure an overactive stick/yoke.
-LAT TORQUE- Leave this value set at 12 unless advised by the factory.
-BAUD RATE- This setting is determined by your GPS, default is 9600.
-BANK ANGLE- This setting determines the approximate bank angle in AP mode only. It has no effect in EFIS mode.
-GPSS GAIN- This setting should be left at 16 unless advised by the factory.
-MICROACTIVITY- This setting should be left at 0 unless advised by the factory.
-YAW DAMPER?- This setting should be left at N unless a Trutrak yaw damper system is installed.
That is the last setting in the lateral setup menu. Now move on to the vertical setup menu. To access the vertical setup menu,
press and hold the EFIS button.
-PITCH AXIS?- Setting this to N will result in the pitch servo being deactivated. When the power is cycled to the system it
will default back to Y with the pitch servo active.
-VRT ACTIVITY- Increase this number to cure a slow porpoise, decrease it to cure a bouncing feeling in altitude hold.
-VRT TORQUE- Leave this value at 12 unless advised by the factory.
-MIN AS- This is the minimum airspeed setting. Set this sufficiently above clean stall speed to prevent aircraft stall but not
high enough to interfere with maneuvering.
-MAX AS- This is the maximum airspeed setting. Set this sufficiently below Vne, but not enough to interfere with
maneuvering.