GSA28 roll servo adjustment

In my RV-7A during my 2 hr. cross-country over the weekend, my G3X/GSA28 autopilot combination tracked the GPS course fairly well. The servo slowly rolled the wings from 1 degree left wing down to 1 degree right wing down over about a 20 to 30 second time period. This was in smooth air.

The roll servo arm is in the middle hole position. What adjustments should be to minimize this? Also, can you enter the configuration mode while the plane is airborne to make the adjustment then have the G3X system restart and try out the setting while still airborne to see how it will work?

Thanks

Using the default settings I found the default roll gain to be too hot for the RV7 with the arm in the center hole. Turned down the gain and found the same performance you are describing.

Spent many flights making changes and analyzing the data logs. There is a ton of data available in the G3X logs!

Along with help from TeamX, I ended up with the following for my RV7:

Roll servo arm in the inner most hole (make sure you use the limiting bracket and ensure that your arm cannot go over center!)
Roll Torque 30% (adjust to your comfort level but give it enough to ensure it is not being saturated by the load. You can look in the logs for this)
Roll Gain 0.30
Fine Adjust Amount 1
Fine Adjust Time 0.20

You can get to these settings via the menu button in flight. They take effect instantly. You have to enable "Show Expert Settings" to be able to see and change the Fine Adjust settings. EDIT: Press Menu and select "Show Advanced Settings", then Press Menu and select "Show Expert Settings".
On the Gain setting, too much and it will be too aggressive in turbulence, too little and it will do what you experienced in smooth air. +-0.05 of 0.30 makes a significant difference in my airplane so you may need to tweak from there for personal ride preference.

Hope this helps!

Brian,

Thanks for giving me a place to start from. It'll give me something to do while enroute on that next long cross-country.

Mike

My settings were pretty close to yours, but I couldn't find the "Show Advanced Settings" selection to adjust the fine settings. Where is it?

Thanks

When you have the page up that allows adjusting the roll gain and torque, press the menu button and you should see it.

I have found that you need to do this twice to get em to actually show since they are "Expert Level Settings". EDIT: Press Menu and select "Show Advanced Settings", then Press Menu and select "Show Expert Settings".

Advanced and Expert Servo Settings

Brantel said:

When you have the page up that allows adjusting the roll gain and torque, press the menu button and you should see it.

I have found that you need to do this twice to get em to actually show.

Click to expand...

Hello,

This has been mentioned a couple of times in this thread that you have to "do this twice" to gain access to these parameter, so we wanted to clear this up.

We tried to simplify the user interface by hiding seldom used servo configuration settings, yet provide access when needed via the Menu key.

As shown on page 27-60 of the Rev. M Installation manual, the Fine Adjust Time and Fine Adjust Amount are "expert settings".

As mentioned in each servo configuration section (e.g. page 27-49 for the roll servo) there are advanced and expert settings which are enabled by selecting Menu, Show Advanced Settings and Menu, Show Expert Settings.

The menu actions required to make the advanced and then expert settings visible is what is being referred to in this thread as "doing this twice".

Thanks,
Steve

g3xpert said:

Hello,

This has been mentioned a couple of times in this thread that you have to "do this twice" to gain access to these parameter, so we wanted to clear this up.

We tried to simplify the user interface by hiding seldom used servo configuration settings, yet provide access when needed via the Menu key.

As shown on page 27-60 of the Rev. M Installation manual, the Fine Adjust Time and Fine Adjust Amount are "expert settings".

As mentioned in each servo configuration section (e.g. page 27-49 for the roll servo) there are advanced and expert settings which are enabled by selecting Menu, Show Advanced Settings and Menu, Show Expert Settings.

The menu actions required to make the advanced and then expert settings visible is what is being referred to in this thread as "doing this twice".

Thanks,
Steve

Click to expand...

Thanks for clarifying this Steve..