Trio Pro Pilot gains

[rocketbob]

Installed a new Trio Pro Pilot in 55BC and am wondering if anyone that has one could share their VNav gain settings. I'm finding after turning the servo gain down in roll it behaves nicely in that axis. In pitch it will hold altitude fine, but when using the altitude preselect I find that it will quickly pitch to get whatever VS I have set and once it gets to the desired selected altitude, it will overshoot slightly then sort of abruptly pitch down to kill the vertical speed. A couple of times it disconnected with a brief flash of the G-Limit warning in smooth air without anything resembling more than 1G.

[Sam Buchanan]

Originally Posted by rocketbob

Installed a new Trio Pro Pilot in 55BC and am wondering if anyone that has one could share their VNav gain settings. I'm finding after turning the servo gain down in roll it behaves nicely in that axis. In pitch it will hold altitude fine, but when using the altitude preselect I find that it will quickly pitch to get whatever VS I have set and once it gets to the desired selected altitude, it will overshoot slightly then sort of abruptly pitch down to kill the vertical speed. A couple of times it disconnected with a brief flash of the G-Limit warning in smooth air without anything resembling more than 1G.

Bob, call the guys at Trio, they will walk you through smoothing out any wrinkles in your installation.

But if you want to try it yourself, you might start with minimum gains then work up until the autopilot flies the way you want it. It should smoothly transition to 200fpm as it gets within a hundred feet of selected altitude then capture the altitude. 200fpm isn't aggressive enough to feel much of a transition to capture. If you have a steeper climb/descent than 500fpm as your default, set it back to 500fpm so the level-off will be smoother.

[Capflyer]

Which EFIS is the ProPilot coupled to and is it through an ARINC module?

[rocketbob]

No EFIS and yep I know I can experiment with the gains but I would rather plug in the three VNav gain numbers and be done with it. Gas ain't cheap anymore.

[Sam Buchanan]

Originally Posted by rocketbob

No EFIS and yep I know I can experiment with the gains but I would rather plug in the three VNav gain numbers and be done with it. Gas ain't cheap anymore.

I'll see if I can remember to check the gain settings when I'm at the airport Saturday.

[rocketbob]

Very good, thanks Sam!

[Capflyer]

Try these for your VNAV Gain AH-30/VS-35/AS-50 I had the same issue and it took some experimenting with the gains to get it somewhat better. These seem to work for me in my RV4 but quite honestly as soon as I put a passenger in the back all gain settings are out the window. I'm still waiting on Chuck at Trio to come out with an updated software that can account for change in CG for a tandem seater and the problem they have is he tests everything in his RV9. He is very good to talk to so don't hesitate to call him if you continue to have issues.

[Sam Buchanan]

Bob, here is what is flying in my Pro in the RV-6:

ALT HLD=30
VS=35
VNAV SERVO DB=6
default rate=500

Hope this helps,

[rocketbob]

Thanks guys. 30/35/50 was the default setting. That was leading to overshoot and some light negative G when using the altitude select and the desired altitude reached. Right now I'm at 20/20/50 with 200fpm default and that seems to work smoothly. I am having another problem with random G-limit disconnects that I will have to work out thru Trio.

[Sam Buchanan]

Originally Posted by rocketbob

Thanks guys. 30/35/50 was the default setting. That was leading to overshoot and some light negative G when using the altitude select and the desired altitude reached. Right now I'm at 20/20/50 with 200fpm default and that seems to work smoothly. I am having another problem with random G-limit disconnects that I will have to work out thru Trio.

Be sure you don't have a static leak. If everything isn't tight just opening a cabin air vent can cause the autopilot to wander.