Pitch trim/Sync

[cmarbach]

Our Skyview autopilot is calling for a trim adjustment. If we adjust the trim to quiet the Skyview, the airplane is way out of trim and when we disconnect the autopilot it pitches up 20-30 degrees.

I'm wondering if anyone else is having or has had this problem??

 

[rvator51]

Has the trim position sensor been calibrated? (SETUP MENU > HARDWARE CALIBRATION > EMS CALIBRATION)

 

[meljordan]

Carl,

Do you have the autopilot rotation limiting bracket installed on the pitch servo? If so, take it off and check to see if it or the screws used to mount it are magnetized. If it is magnetic you will need to demagnetized it and I recommend stainless or brass screws to mount it. You can also leave It off as long as there is no possibility for the arm to go over center.

Regards,
Mel Jordan

 

[Dynon]

The trim widget calibration won't fix it. But Mel's on the right track. In fact, it's possible, we think, in some circumstance, for the bracket itself to influence the trim sensing. We're currently investigating this. So you might try removing the limiting bracket to see if that improves things (the limiting bracket should only be used as a failsafe - your normal control stops should be primarily preventing the possibility of going over-center)

 

[cmarbach]

With the bracket removed the problem is solved. We put the screws back and it still works fine, so the bracket is the culprit. We plan on making a non-magnetic bracket out of aluminum.