Hey out there..
My Dynon Skyview autopilot in my 3B is acting up and won’t hold altitude (nor maintain a VS) for more than a few seconds before it starts hunting up and down.
Would like to hear from anyone who has had this issue and found a solution.
Thanks
Is this new behavior or has it always been this way? I have noticed if I move the aircraft within about 2 minutes of powering up the autopilot I have issues holding altitude. If it’s always been this way you probably need to adjust the autopilot settings. Someone with a RV3 might speak up with settings to use as a start point. If not RV4 settings might be a good start point.
Not sure about the Skyview, but My AFS setup includes Dynon autopilot and servos. You can download the AFS manuals and they provide a great troubleshooting matrix for exactly your problem.
The latest Dynon/AFS autopilot tuning guide link is below. It is for Skyview Software Version 16.4 and AFS Software Version Vx16.10.
Section 2.7 includes a test to identify a broken shear screw in the pitch servo, which could be your issue. The new guide includes other good stuff as well.
A failed shear screw may or not be your problem. I had a Dynon shear screw fail a few years ago, on the SV-32 pitch servo in my RV-8.
Per Dynon, they adopted a new design shear screw that was available late in the 1st quarter of 2017. It was a redesign due to a premature fatigue failure of the old design screw during normal use.
I called Dynon after verifying the shear screw had failed and they quickly sent replacement shear screw kits gratis (including one for the roll servo for if/when it fails). The kit includes the shear screw, an Allen wrench, a cotter pin, thread locker, and instructions for replacement.