Uncontrolled roll in autopilot basic mode in multiplayer

[Kobal]

Hi, tested on two servers, with a teammate, me with FFB, him not, when we activate autopilot basic mode, the plane roll to the right or to the left until autopilot disconnection. No problem in solo flight.

Edited May 19, 2023 by Kobal

[fausete]

The problem was present in both FFB and non-FFB aircraft? Were you flying in each-others wakes? What flight conditions?

Edited May 19, 2023 by fausete

[Kobal]

Yes, problem for both, during standard climb and cruise. Wingman in echelon formation far away from wake turbulence risk (with no wake turbulences on server).

Edited May 19, 2023 by Kobal

[Buster0083]

I can report the same, I thought I must have imagined it working properly in single player but yeah - in MP only, engaging basic mode the AP starts to add roll trim in one direction or the other until the aircraft rolls to about 40-50° then kicks off the autopilot. It's most commonly rolled right for me but I've seen left too.

[fausete]

Hi, thanks for the clarification. It is quite strange that the problem only shows in MP, we'll investigate.

[Buster0083]

Quite strange, haha - for what it's worth I just tried the F1-EE instant action cold start mission and the autopilot works fine; online ten minutes later it again started inputting roll trim to the left, this time. 

[Kobal]

Autopilot basic mode uncontrolled roll after take-off on server only.

(track is corrupted as usual, but you can see the phenomenum, this is the essential).

Autopilot roll problem.trk

Edited May 20, 2023 by Kobal

[Bremspropeller]

Concur, AP engagement leads to immediate roll-trim divergence in MP.

SP is fine.

[Mavkruger]

i have the same problem, even in SP, after 20min of flight for the SP

[Iron Sights]

Yeah, flying today on ECW and put on AP, it started to roll. Rolled so hard AP disengaged. Then I ended up having to trim back. Also noticed the roll comes back at high speed as well. Just weird behavior, I’ll try it again later and try to document.

[Kondor77]

Happened to me last night. Also using MT. Will try ST later to see if it also occurs there. 

[Cine]

hello

I have the same issue. Sine the last update of Open beta version, Auto pilot is not working any more. ALT seems to be OK but not CAP !

 

 

 

[Erk104]

Yes I am having this issue as well

[Schrute, Paper Sales]

Ditto, exactly as described above.

[fausete]

We think this issue is now fixed internally.

[Kobal]

Confirmed, thank you.

[grim_reaper68]

Hi 

Just made a flight on Sinaï Map, and after a while, the AP rolls to the left. But the strange thing is that the trim indicator was full right and the aileron too, but the mirage rolls to the left... It seems to be the aileron trim who deviates slowly. I've maid a second flight and the rolling bug appears after  1 hour of flying with the AP. I joined the track. When i look from outside, the aileron are moving like the trim indicates, right up and left down. When the AP disconnect, they still stay in that position, but the aircraft violently rolls to the left. It reacts like if the tanks are emptying assymetricaly, but no indication on the tanks indicator.   

DCS F1 long flight AP bug.trk

Edited July 2, 2023 by grim_reaper68

[fausete]

Hi @grim_reaper68. I've not had time to look at the track but are you perhaps overspeeding the aircraft? When a certain IAS is exceeded, you have control surface authority reversal due to aeroelasticity. The best part? Depending on ambient temperature and altitude the impact temperature will be lower than the 135 °C required to trigger the LIM warning light.

[grim_reaper68]

Hi. No overspeed, between 350 and 400 kts, altitude  established at 12000ft. I took some screenshot, you can see the time line on the clock. Take off time on 12.00. 

On the first screen the trim indicator doesn't appear, but you can see that the fuel quantity indicator become visible. On the ohter one, the angle of the trim grows up, as seen on the input window on the left. No action on the stick at any time. I was just flying in autopilot, changing bearing with the bearing selector.  

Another fact is that the aileron didn't move in a left turn with autopilot. In the screen below the F1 has engaged the turn, but if you look at the left aileron, it's down.

Hope i'm clear in my explanation.

I forgot to mention that i was in SP. I've tested it twice with the same result.

Edited July 2, 2023 by grim_reaper68

[fausete]

In that case, especially what you explained before in the first post is very strange behaviour. We'll investigate and debug the TRK.

[grim_reaper68]

I think I have a part of the answer: I made a third test, in calm conditions (static weather, no wind, the 2 first where made in dynamic weather, so there was some wind) and after 2 hours of flying, no drift of the roll axis. The AP works perfectly. A little bit of right aileron was present, but I think i cames from the BARAX and PHIMAT pods who have different weights. For a complete information, I was loaded with 2 Magic II, Phimat on the left, Barax on the right, 1 full loaded RPL201, and 2 full loaded RP35, so a very heavy aircraft on both first flight. On the third (no wind), I dropped the 2 RP35 about 20-30 minutes after take off. 

I just made another test, with the full load config all the flight and no wind. The roll drift cames back. As soon as the RP35 where empty (both lights on at the same time), the F1 began his deadly left roll after 5-10 minutes. So, maybe there should come from the 2 RP35. It's like they would emptying at different speed. 

PS: I didn't try it with only the 2RP35. I will make it later to see if it's the same.

 

Edited July 3, 2023 by grim_reaper68

[fausete]

Thanks a lot for the investigation, it really helps to narrow down the problem. I imagine this happens irregardless of what map?

Edited July 4, 2023 by fausete

[grim_reaper68]

Good question, i will make some other test on different maps

 

[grim_reaper68]

Test on Syria give the same result. But if i drop the 2 RP35 before the critical point, the F1 seems to recover its attitude. depending on the position of the trim indicator, the F1 will start to roll to the right, and i was able to trim it to neutral fight again. 

The test with only the 2 RP 35 under the wings is OK. No trim drift.

 

[fausete]

So it's only with a certain payload config that it happens then?