TruTrak GSGV - Need Help

TruTrak VSGV - Need Help

I have a TT VSGV autopilot (blue screen) that doesn?t seem to want to work.
I have a Garmin GTN650 that feeds the A/P
I have gone through all the setups & used the recommended settings. I feel I?ve got it right.

Here?s the sequence:

After Engine start
Avionics ? ON
Autopilot ? Power-up & initialize screen sequence: ?D-IIR VSGV V2.51?
then ?NO GPS PWR UP?
Once GTN captures satellites ?GPS OK AP OFF? (with blinking asterisk)
As I taxi, the screen will show ?TRK (with the appropriate compass heading) and AP OFF?
(Note: I have also performed the ?GYRO SET? function while stationary)
After take-off, at altitude & trimmed, I can turn the A/P ?on? and the plane enters an immediate right, nose-down bank. It is aggressive enough that I need to dis-engage A/P immediately.
When I enter a ?Direct-To? on the GTN & activate, the blinking asterisk turns to a blinking plus (+). As I understand, this indicates an available flight plan. When I turn the A/P ?on?, it?s the same result. The plane enters an immediate right, nose-down bank.
I did talk to Lucas about three weeks ago & he suggested I try the ?Gyro Set?, which I did.

Can anyone think of anything else I need to do; or have had a similar experience with solution before I call TT again?

Thanks for any help with this.

EFIS

Do you have an EFIS and is it perhaps controlling the autopilot? It sounds like it's trying to follow a heading bug maybe. Typically a switch is installed to select between the GPS or the EFIS.
Probably you know that but you didn't mention other equipment.
Tim Andres

Do a ground test with the GPS off and see if it controls roll and pitch correctly. It could be a reversed pitch servo and/or roll servo. To do this test, turn on the AP and roll the knob to the left (probably read in degrees of turn) and the stick should go left, and right for right. Then go to vertical speed and set a 500fpm climb and the stick should move aft, and vice versa. Let us know if this works and maybe we can help further. Personally, I have NEVER had to do a Gyro set with any TruTrak AP, and I have worked with a lot of them.

I do have a Dynon D100, but it's not controlling the A/P.
The A/P has serial GPS & ARINC connections to the GTN650 navigator.

Jesse
I have done the test you described. Turn encoder knob CW, stick makes a right bank; CCW, left bank. In vertical mode, CW rotation stick goes back, CCW stick goes forward. If I turn the A/P on, on the ground sitting still, the stick starts moving right & forward. One thing I haven't done is to switch off the GPS signal to see what the behavior is. I'll give that a try in the morning.

Ok, this morning (in the hangar) I pulled the breaker on the GTN & initiated the A/P. I leveled-up the ailerons & elevator. Turned the A/P on and the stick again starts a right, nose-down bank. I can turn the encoder knob and get the lateral going to the left, but by this time the elevator is getting to the nose down stop & I have to push the CWS to release everything & get the stick back to neutral. I can also rotate knob in vertical mode & get the correct stick response.
I know I'm going to eventually get this thing to work. I hear too many good things about TruTrak and their rock-solid performance. I just wish it were sooner than later.

Any other suggestions for things to try?

Sam, how long did you perform the gyro set? It'll need to be at least 45 seconds, if it's shorter, it won't cure the problem. If that doesn't cure it, we might need to take a look at it. Please let me know.

TrutrakTech said:

Sam, how long did you perform the gyro set? It'll need to be at least 45 seconds, if it's shorter, it won't cure the problem. If that doesn't cure it, we might need to take a look at it. Please let me know.

Click to expand...

Lucas
I probably didn't hold it in for much more than 10 or 15 seconds. I'll go out & give it the longer push. Does the plane need to be outside & have a GPS signal? Or can I do this in the hangar?

Thanks much for your help.
Sam

You can do it in the hangar, GPS signal not required. But give it a nice long minute of time.

So far, so good!...NOT

Lucas

I gave it the gyro set for a good solid minute, then turned the A/P on.
What a relief it was to see the stick remain steady. Other than a tiny bump of the servos every 10 or 15 seconds, one way or the other, it stayed steady. Very much improved!

If the wind wasn't gusting to 26, I'd be out right now doing the real test!
Maybe tomorrow.

Lucas, thank you very much for the help. I'll report back here after a test flight.

Edit: Well, just when things were looking up, I took N82SE up for an A/P test. No joy. Same results...right, nose-down bank. Ended up talking to Zack at Trutrak & did yet another test relating to CWS. No improvement. Took the unit out & it's on its way to Trutrak. Still anxious to get the first taste of an A/P working in my RV.

Anytime!

Glad I could help.