I did a flight the other day with the RV-7. Engaged the autopilot after takeoff with a climb of 1200fpm. At fl120 hit the alt button to Alt Hold. I then let her cruise for 2 hours and she never lost altitude. Have you tried uninstalling and reinstalling the aircraft?

 

I will try that right now. Are you using the Reality XP in the plane?

Hope you can get it worked out. The RV is a real joy to fly. I have taken it halfway around the world from California to Singapore, via Pacific northwest, Alaska, Russia, Japan, Guam, then Island hopping to NZ and Australia, Indonesia, then to Singapore. Someday I will finish the journey and go all the way round lol.

Hope you can get it worked out. The RV is a real joy to fly. I have taken it halfway around the world from California to Singapore, via Pacific northwest, Alaska, Russia, Japan, Guam, then Island hopping to NZ and Australia, Indonesia, then to Singapore. Someday I will finish the journey and go all the way round lol.

 

Around the world! Very Nice, I love this plane but after a clean install it still does not want to hold ALT. I guess I should wait on Danny to register me for the BayTower forums. I did everything you guys have been telling me to do but still it does the same thing. :Sigh:. I am out of ideas.

How are your frame rates in general? I know the alt hold can be more difficult to use when frames are low...ie flying around Seattle with AI/Weather and so on. Try going to a place such as middle of the desert, clear weather...etc and see how it works there.

How are your frame rates in general? I know the alt hold can be more difficult to use when frames are low...ie flying around Seattle with AI/Weather and so on. Try going to a place such as middle of the desert, clear weather...etc and see how it works there.

 

I get a good 20 to 25 FPS while flying this plane. :rolleyes: ( I like how this plane does not hit my frames hard like some other planes in my hangar!) On the autopilot itself I noticed Horizontal bars going up and down sometimes, I read that you should trim down if the bars are going down and trim up if bars are going up. Are you suppose to trim when AP is on? Then after 30min or so the bars don't appear then it seems like the ALT mode is not holding the altitude I want it at.

Did you try "Elevator trim" setting for the autopilot?

 

And do you possibly have trim assigned to a controller that might fight the autopilot?

 

I find that moving the stick/yoke to center the elevator reduces the bars

going up and down.

 

Danny's advice is to the enlarge the elevator null zone a bit if the autopilot

is unhappy..

the bars moving up and down on the autopilot is just the indication that the autopilot is adjusting the trim up or down, you don't do anything. (servo type set to Elv+trim or Trim...servotype Elev only I think you need to manually adjust trim when indicated) After the autopilot 'trims' the plane to desired vertical speed, you won't see the bars move up or down until it needs to make another adjustment, such as hitting turbulence, or a change by you. Flying in smooth air with no turbulence, you wont see the bars move up and down very often, since the autopilot does not need to make many adjustments. While flying a long trip cross country, one way to see if the alt hold is still working is to once in a while change the VS speed, then bring it back to 0. You should see the bars moving up and down on the AP indicating that it is adjusting to your command.

 

 

 

Cheers

TJ

Did you try "Elevator trim" setting for the autopilot?

 

And do you possibly have trim assigned to a controller that might fight the autopilot?

 

I find that moving the stick/yoke to center the elevator reduces the bars

going up and down.

 

Danny's advice is to the enlarge the elevator null zone a bit if the autopilot

is unhappy..

 

Yep I tried the Elevator trim and it did not hold the VS at all. I will try putting the null zone up a tad and see what happens. I do have 2 buttons on my joystick that are my trim buttons.

Yep I tried the Elevator trim and it did not hold the VS at all. I will try putting the null zone up a tad and see what happens. I do have 2 buttons on my joystick that are my trim buttons.

 

I have two buttons for electric trim as well, and that does not interfere.. so that is likely not the issue.

Just want to make sure this is what AP is suppose to look like while its on.

 

 

After I took this pic, it was not holding the ALT again! :angry: I tried adjusting the VS and it was not responding.

Edited January 4, 201313 yr by firehawk44
Image removed. Exceeds 400KB policy limit.

Yeah your panel looks normal, here is mine during a trip awhile back from Norfolk Island to Brisbane YSNF-YBBN.

 

 

Climb

 

 

 

Cruise

Edited January 4, 201313 yr by firehawk44
Images removed. Exceed 1600W and far exceed the 400KB limit.

Yeah your panel looks normal, here is mine during a trip awhile back from Norfolk Island to Brisbane YSNF-YBBN.

 

What the heck. I don't know why mine is not holding ALT at all. :mad: It was happening on my yoke and joystick.

Have you calibrated your hardware lately? Perhaps an axis is kicking the AP off after a while. Just to clarify - when the AP gauge has those bars it means its trimming the servos. Don't touch your trim or yoke/stick.

Here is mine, climbing at 800 fpm, 300 fpm, hold at 2500 feet.

Have you calibrated your hardware lately? Perhaps an axis is kicking the AP off after a while. Just to clarify - when the AP gauge has those bars it means its trimming the servos. Don't touch your trim or yoke/stick.

 

Yep, I first thought that my Joystick was not calibrated, I did that and it still did not work. I also did a flight without touching the trim while it was on ALT hold but it still did the same thing. :mellow:

 

Here is mine, climbing at 800 fpm, 300 fpm, hold at 2500 feet.

 

I see that you don't put your AP on GPSS, you only keep it on heading SEL. Maybe that's the problem? I always but it to GPSS while in cruise. Unless that does not matter.