TruTrak Autopilot issue

[rw2]

I have the TruTrak autopilot shown in the attachment and have a problem. It wanders 10 degrees either direction. It's installed in an experimental Maule, but a friend told me that this old unit used to be quite popular in the RV community and that maybe someone here would have an idea.

You can see the problem clearly in a video I made here: https://youtu.be/b-ds_jEp5LM?t=83

Any help would be greatly appreciated. Maybe it's just a bad unit, but thought it was worth asking.

[Mike S]

Rich, welcome aboard the good ship VAF

[rw2]

Originally Posted by Mike S

Rich, welcome aboard the good ship VAF

Thanks Mike!

[mike newall]

Download the instructions, go back to square 1, re align everything from scratch.

When you turn it on, always allow it to erect itself when you are absolutely still on the ground.

This was sage advice from Andrew at whoever Trutrak are now and worked for us.

[rw2]

Originally Posted by mike newall

Download the instructions, go back to square 1, re align everything from scratch.

When you turn it on, always allow it to erect itself when you are absolutely still on the ground.

This was sage advice from Andrew at whoever Trutrak are now and worked for us.

I didn't do the installation on this, so probably good advise in any case to verify that everything was done correctly. I'll give it a try. Thanks for the tips.

[Ironflight]

I’ll second the comment to not move the airplane until you see it finish its boot-up cycle - you’ll know that when it says “autopilot Off” (at least on our TT’s - not absolutely sure what you’ll see, but it takes about 30 seconds). If you power it up while you’re moving, it’ll never settle down….

[TruTrakAndrew]

The advice given here is great!
1. Check control/autopilot system for lost motion.
2. Don’t move until boot is complete.
3. Make sure you have a good GPS signal to the AP for best performance.
4. Look at AP settings (the advice to start again from base settings and adjust one thing at a time is perfect).
5. As always, shoot me an email…while I may not be the fastest to respond, I do try to help everyone that has a TruTrak make it fly as it should! :-)

[moosepileit]

check the shear screw.

[rw2]

Originally Posted by TruTrakAndrew

The advice given here is great!
1. Check control/autopilot system for lost motion.
2. Don’t move until boot is complete.
3. Make sure you have a good GPS signal to the AP for best performance.
4. Look at AP settings (the advice to start again from base settings and adjust one thing at a time is perfect).
5. As always, shoot me an email…while I may not be the fastest to respond, I do try to help everyone that has a TruTrak make it fly as it should! :-)

1: I don't know what that means.
2: Wilco
3: No GPS. Heading only on this one.
4: Wilco
5: Thanks!

[BobTurner]

Originally Posted by rw2

1: I don't know what that means.
2: Wilco
3: No GPS. Heading only on this one.
4: Wilco
5: Thanks!

1. Check for any free play between autopilot servo and ailerons/elevator. This includes prior suggestion that maybe the shear screw is sheared.
3. Andrew: my recollection, maybe faulty, was that ‘heading’ was actually gps track?? If so I don’t know what happens with no gps.
OP: mid-continent instruments now provides service, although this unit is pretty old, I’m not sure.