TruTrak ADI Pilot II - Manual (Page 10)

TruTrak Flight Systems ADI Pilot I & II Autopilot Installation Manual
December 2009 8 8300-012 Rev B
TOWARD RIGHT. ROTATE KNOB COUNTER CLOCKWISE,
FLIGHT CONTROL MUST MOVE BACK TOWARD LEFT.
IF ADI P II, MOVE TAIL UP AT LEAST A FOOT AND THE
ELEVATOR MUST MOVE UP AT SAME TIME. MOVE TAIL
DOWN AT LEAST A FOOT AND ELEVATOR MUST MOVE DOWN
AT SAME TIME.
ADI Pilot I First Flight
The first flight should be done after having completed all the setup and testing on the ground. For the first flight, it is important
that the GPS unit is properly functioning with the autopilot. As discussed earlier, when there is proper connection to the serial
input of the autopilot, the display will show “OFF” when it is disengaged and valid GPS data is present. Once the GPS ground
speed is sufficient, the display will switch to the digital DG and show the current gyroscopically smoothened ground track. If
this does not occur, it is best to diagnose and fix the problem prior to first flight of the autopilot.
The activity adjustment (setup screen 1) determines how briskly the autopilot responds to roll disturbances. The setting can be
adjusted, in flight, over a wide range; thus the autopilot can be tailored to adapt to any aircraft installation. The activity
adjustment covers a numeric range of 0 to 24. Unless the value for a particular aircraft is provided by TruTrak, it is advisable to
start with a setting of zero and work up from there. Most installations would ultimately require somewhat higher settings.
On the first flight, manually fly the aircraft to a suitable area for testing. Engage the autopilot by pressing and releasing the
knob. Observe that the display now shows the captured GPS ground track as the selected direction of flight.
Press and hold the knob for approximately 4 seconds until the first setup screen is shown on the display. The digit “1” will be
flashing, followed by the activity value that was set earlier during pre-flight setup. Use the knob to select the value zero (0),
and observe the resulting control movement. Using the knob, increase the value one setting at a time, taking time to observe an
increasing level of control response. At some point, if too high a setting is chosen, the autopilot will be jittery and over-active.
Back the setting down using the knob until the autopilot is responsive but not over-active. It is best if these adjustments are
made in conditions of light to moderate turbulence (the TruTrak loves turbulence) so as to make it easy to observe the response
of the autopilot to disturbances. It will be noted that a fairly limited range of activity setting will be acceptable; too low a value
will result in sluggish response, while too high a value will result in nervous, inappropriate response. Within this acceptable
range there is room for individual preference; some people prefer a more aggressive autopilot than others. It should be noted
that any builder can accomplish this adjustment procedure and no professional is required. Once the desired activity level is
established, press and release the knob to store the value and move to the second setup screen.
In the second setup screen, the digit “2” will be flashing, followed by the torque value that was set earlier during pre-flight
setup. Again, it is best that this be done in light to moderate turbulence. The reason is that more torque is required of the
autopilot in turbulence than is the case in still air, because the velocity of the servo is greater as turbulence requires more rapid
servo movement. This means that the higher the activity setting, the higher the required torque setting.
The reason for setting the torque to a setting less than its maximum (12) is to reduce the current draw of the servo and to make
it easier to override the autopilot should the need arise. Manual override is not normally required, as using the control-wheel
switch or the knob will disengage the autopilot, but it is best to have a setting of torque which can be comfortably overridden if
necessary. Starting with the maximum torque setting (12), gradually decrease the value using the knob, until it is observed that
the autopilot no longer has the necessary torque to respond to disturbances; then increase the setting somewhat from that level
using the knob until no more slippage of the servo is observed. The clearest evidence of servo slippage is that the autopilot is
no longer able to roll the aircraft back to a level attitude after a roll disturbance occurs.
Once the desired torque level is established, press and release the knob to store the value. Press and release the knob two more
times to skip over setup screens 3 and 4 and return to the primary flight display in which the selected GPS ground track appears
on the display.
The setup procedure can be repeated whenever it is desired to modify the dynamic flight characteristics of the autopilot.
ADI Pilot II First Flight
The first flight should be done after having completed all the setup and testing on the ground. For the first flight, it is important
that the GPS unit is properly functioning with the autopilot. As discussed earlier, when there is proper connection to the serial
input of the autopilot, the display will show “OFF” when it is disengaged and valid GPS data is present. Once the GPS ground