My AP doesn't wanna keep horizontal flight

[guilhermelissandre]

Hello folks,
I have a Skyview D1000T w SV42 SP Servos and panels.
My AP does not want to keep straight horizontal flight, is riding 100 feet up and 100 feet down, but it doesn't happen all the time. Wich pitch "In-flight" parameter shoud I change (Torque, Gain, Sensibility)? I think it's a common issue.
My airplane is a Sport Cruiser with Rotax 100hp.

All the best,,, Guilherme

 

[Raymo]

This is usually caused by fluctuating static pressure, which the AP senses as an altitude change and tries to correct.

What type of static ports are you using?
Have you tried disconnecting the static port and letting it read the pressure inside the are where the ADAHRS is located?

 

[Dynon]

So the best way to tune the AP is to use the autopilot in-flight tuning guide, which you can grab at http://docs.dynonavionics.com. But before you do even do that, you'll want to make sure that there is no slop in any linkages or control surfaces. And if you're seeing any SLIP annunciations during altitude excursions, then those need to be addressed first by either upping the torque or using a stronger servo. But assuming all of that checks out, then one thing to look into are ALT GAIN and VSI Gain. ALT GAIN should be about 1/2 of VSI GAIN.

 

[guilhermelissandre]

Thanks for the help, I will try to check these parameters and I will also see the static pitot input. In my opinion, the servo is ok cause my airplane is a Sport Cruiser, nothing so heavy!

1- Tunning guide
2 -Torque
3 -ALT GAIN X VSI GAIN (ALT = 1/2 VSI)
4 -Static Port

All the best,, Guilherme