F-15C Autopilot still do not function correctly.

[303_Vins]

When ATTH + BALT is set even during level flight, aircraft  commence  slowly fly nose down. More and more.  Do not keep altitude at all.  Keeps but just 20 to 30 seconds, than begins to descent...

Speed is correct, throttle correct. No any inputs to HOTAS done... after AP engaged...

Can anybody fix it PLS ?

Edited May 24, 2021 by 303_Vins

[cofcorpse]

Could you attach a track showing this problem?

[draconus]

@303_Vins Do you use FFB joystick by any chance?

[303_Vins]

I do not use FFB.  X-52 modified/moded/deadzone 6 in DCS.

 

Track : https://drive.google.com/file/d/18zjP7RTQARN5RlM9qQH-C5lOI1fvCaHt/view?usp=sharing

 

As seen in track, AP do not keep Attitude to long.  Pitch and Bank changes.  After applying Altidute Hold, do not keep anything.

Function shortly jus if bank is less than 20 degs and very level flight before angaging Alt Hold is required.

Finally AP commence to change Attitude and Altitude without any stick input. 

Edited June 3, 2021 by 303_Vins

[303_Vins]

I have found the cause of AP malfunction.  Because manual trim is not disconnected after AP is applied.

Any manual trim input has an impact to aircraft behavior during AP applied. It should be disconnected.

If not, AP do not trim aircraft itself because manual trim override.

Each small stick input for pitch or bank sholud be countered by AP.  AP shoul reestablish pitch and bank itself. This not happens.

Edited June 3, 2021 by 303_Vins

[Vekkinho]

Yes, trim is still functional when you flip ATT and ALT hold switches (default S and A keys). You gotta trim it straight and level to engage autopilot and but you can still use trims with ATT and ALT toggled. Dunno how it functions IRL but I guess this is a mistake by devs.

[Nealius]

How did you get autopilot to engage at all? I've tried ALT hold and autopilot engage and the autopilot doesn't work at all.

[Vekkinho]

You gotta trim her first and pitch and bank should be <5° in order to function. 

 

Also try pitch, roll and yaw hold, I can't remember default keys as I've customized my F-15C.diff.lua.

 

This is CAS, it's no classic "autopilot" you might think of, it won't put you on course to a next waypoint or steer between those.

[303_Vins]

Trim input should be disconnected when AP is applied. Otherwise AP will not be able to function properly. This is code issue.

I do not understand why responsible people do not read bug reports. Minor bugs but still...and annoying, realy long time...

Edited August 1, 2021 by 303_Vins

[303_Vins]

On 7/16/2021 at 10:08 AM, Vekkinho said:

You gotta trim her first and pitch and bank should be <5° in order to function. 

 

Also try pitch, roll and yaw hold, I can't remember default keys as I've customized my F-15C.diff.lua.

 

This is CAS, it's no classic "autopilot" you might think of, it won't put you on course to a next waypoint or steer between those.

Nope. Normally ATT Hold should keep any desired pitch and bank. After applying Alt Hold ( BALT). Plane should keep  bank and change pitch to fly level.

 

[Nealius]

I engage autopilot when trimmed level flight, 0 bank. Doesn't work at all, and I drift on both pitch and bank when I let go of the stick. 

[cofcorpse]

If you still has a problem, could you provide a new track, please?