I have been flying Simstudio's RV-14 using it autopilot and I'm having a hard time to intercept and hold ALT using IAS (climb) or VS (descent). Even I just let AP hold the current ALT, it keeps oscillating up and down, sometime by couple 1000 ft. 

I tried similar autopilot on Asobo's plane, such as X-cub, and it has no such problem at all. IAS and VS modes work just as expected and ALT holds perfectly. So could it be something is broken in SWS' RV-14 autopilot? I bought the RV-14 from MSFS Marketplace, maybe I'm missing some key updates? 

Overall, I love RV-14. Just perfect for GA cross country. 

Not sure... it has been solid for me.

Are you using the WT GNS?

Yes I think I do have WT GNS (from Marketplace too?) installed. Since RV-14 has not GNS  I never thought that could be a problem. So this could be due to some kind of conflict between WT GNS and RV-14's autopilot? 

Edited November 21, 20223 yr by FlyIce

59 minutes ago, FlyIce said:

So this could be due to some kind of conflict between WT GNS and RV-14's autopilot? 

The WT GNS autopilot stuff is not even active (or able to be active) if the GNS is not actively in the current aircraft, so no.

I'll remove WT GNS just to give it a try. The thing puzzles me is that Asobo's X-Cub G3x+ AP works just fine, and G3x and AP in RV-14 cockpit should the same Asobo stuff. 

 

13 minutes ago, FlyIce said:

I'll remove WT GNS just to give it a try. The thing puzzles me is that Asobo's X-Cub G3x+ AP works just fine, and G3x and AP in RV-14 cockpit should the same Asobo stuff. 

 

What GPS are you using?  I have been using the TDS GTN 750Xi for months without any autopilot issues..

Edited November 21, 20223 yr by Bert Pieke

I was just flying the RV-14A with G3x touch, AP control and GTN750 built-in. 

I bought the TDS GTN750xi and found it won't integrate into the RV-14 from marketplace (or I could be doing sth wrong). Since SWS has RV-14 on sale for $10 I just bought it again, installed with TDS version, deleted the marketplace version and the 750 works well. 

However, the "Direct to" function does not sync between G3x touch and TDS 750. Direct to airport on TDS does nothing on G3x and vice versa. Anyone has a solution? 

As to AP ALT mode, I found that I have ti make sure the trim is set properly prior to engaging AP, or the airplane will bob up and down like crazy and can be eventually out of control. 

 

Edited December 4, 20223 yr by FlyIce

4 hours ago, FlyIce said:

However, the "Direct to" function does not sync between G3x touch and TDS 750. Direct to airport on TDS does nothing on G3x and vice versa. Anyone has a solution? 

Not sure what you are asking... DTO on the GTN should produce a magenta line and DTK that the autopilot will follow in NAV mode.  In the default, the PFD does not show waypoint names from the GTN, but that can be fixed by installing my G3X mod (disable the WT G3X mod if you have it installed!)

Unzip and drop into your Community folder:  https://www.dropbox.com/s/smay665me20fnob/Garmin G3X mods v8.zip?dl=0

Thanks a lot - your mod works great to let G3X show waypoint information on the top. I would like to see moving maps in PFD and MFD also show the flight route. Is that possible too?

By the way, I noticed that on G3x the waypoint name was shown with an extra "B" at the end. For instance, KJST was shown as KJSTB, etc. Could this be a small bug in the mod?

9 hours ago, FlyIce said:

Thanks a lot - your mod works great to let G3X show waypoint information on the top. I would like to see moving maps in PFD and MFD also show the flight route. Is that possible too?

By the way, I noticed that on G3x the waypoint name was shown with an extra "B" at the end. For instance, KJST was shown as KJSTB, etc. Could this be a small bug in the mod?

The tds gtn needs a promised update to remove the B.

Got it. By all means, thank you for the mod - having wpt info on G3x is so nice. 

I wish I could eventually tame the ALT mode in RV14. It's possible, but so touchy to get it to stay stable. 

20 minutes ago, FlyIce said:

Got it. By all means, thank you for the mod - having wpt info on G3x is so nice. 

I wish I could eventually tame the ALT mode in RV14. It's possible, but so touchy to get it to stay stable. 

There is an issue with the ALT mode.  At least when I press VS it instantly drops or climbs.  I think they need to set the initial VS value to 0 fpm.  

But make sure you're using the AP correctly.  First dial the new altitude you want.  Then press VS (it should default to zero but I think it's a bug) then use the VS scroll wheel to adjust fpm.  It will climb to the selected alt.  

The wrong way is the default Asobo way....  you have to press ALT, then dial a new ALT, then VS to it.  You never press ALT in modern autopilots unless you want to hold the present altitude.

Thanks for the tips. I normally dial the altitude before takeoff and use IAS mode to climb. AP holds the speed fine and switches to ALT mode correctly when reaching set altitude. But then it keeps pitching up and down to overshoot and undershoot by 1000' or more.

Even when I enter level fly first then press ALT to hold altitude, AP engages the same behavior of pitching up and down. The only few times I succeeded to make ALT stable seem to be the ones I trimmed the pitch and speed to be very stable before engaging ALT. 

Based on what you said about VS, maybe I should make sure VS fpm is 0 even though I don't use the VS mode. Will give it a try.

I think IAS mode is screwed up in tht default GFC500 or whatever that is