POSSIBLE BUG - Change in control sensitivity after rearm/refuel.

[DarkFire]

I was flying on the VA server and after wandering around for a bit landed to rearm (with smoke) and refuel.

 

After I took off again pitch sensitivity had massively increased - it almost felt as though I was flying in direct mode though I wasn't. Both pitch control and pitch trim were extremely sensitive to the point where I could barely maintain level flight.

 

Unfortunately as it was on an MP server I couldn't save a track, nor did Tacview record what happened because I'd crashed earlier and got a new aircraft.

 

Attached is my game log, hope this can help on its own...

[Ironhand]

There is always a track saved automatically in the Saved Games Folder/Tracks/MP, when you fly online. You might want to run it and see if you can spot anything.

[Axion]

Did you reset pitch and trim - Lctrl + T (IIRC) prior to takeoff after you remarmed and refuelled? If not, then that could be a possible contributory factor.

[DarkFire]

There is always a track saved automatically in the Saved Games Folder/Tracks/MP, when you fly online. You might want to run it and see if you can spot anything.

 

Ah, I didn't know about that! I'll check that.

 

Did you reset pitch and trim - Lctrl + T (IIRC) prior to takeoff after you remarmed and refuelled? If not, then that could be a possible contributory factor.

 

Yes, I reset controls to centre several times before taking off again.

 

Edited to add:

 

Found the track. It's a shade over 40MB so I can't really upload it, but everything looked normal. Landing was well within parameters. Didn't see any damage on landing and refuelling and rearming went normally. I'll review it again more carefully tomorrow evening after I get back from work. The only thing I didn't check was whether I'd overspeeded the flaps on takeoff as I used AB which for me is very unusual, though I hit the flaps toggle at 410 Km/h which should be within acceptable parameters.

Edited April 14, 2016 by DarkFire

[Ironhand]

...

 

Found the track. It's a shade over 40MB so I can't really upload it...

If you want, email it to me: flankertraining(at)yahoo(dot)com :: and I'll take a look at it, too.

[SinusoidDelta]

Upload it to Dropbox

[kobeshow]

I seem to have similar issues from time to time, but always assumed I did something wrong, will be interesting to see what comes out of this.

[DarkFire]

OK, the track is uploaded here for interested parties to download:

 

https://onedrive.live.com/redir?resid=D3293A5ED5656179!5067&authkey=!ANDCzhG4XvGwf3g&ithint=file%2ctrk

 

I tried reviewing it again but I have to say that on my potato computer (i7 960, 16Gb RAM, GTX760) track playback is abysmally unreliable. Still, couldn't see any obvious problems that would have caused the control sensitivity issue.

 

Some general observations:

 

1. Apologies for the length. Viewed at real time speed, the full track is nearly 2 hours long.

 

2. A good example is shown of what happens if you accidentally hit the S key instead of grabbing the glass of orange juice that you were aiming for :doh:

 

3. Loss of aircraft no.2 was essentially deliberate. I wanted to see exactly how much G I could pull before airframe destruction. Turns out it's quite a lot, even at nearly 100% fuel.

 

Anyway, general constructive criticism is welcome...

[Ironhand]

OK, the track is uploaded here for interested parties to download:

 

https://onedrive.live.com/redir?resid=D3293A5ED5656179!5067&authkey=!ANDCzhG4XvGwf3g&ithint=file%2ctrk

 

I tried reviewing it again but I have to say that on my potato computer (i7 960, 16Gb RAM, GTX760) track playback is abysmally unreliable. Still, couldn't see any obvious problems that would have caused the control sensitivity issue.

 

Some general observations:

 

1. Apologies for the length. Viewed at real time speed, the full track is nearly 2 hours long.

 

2. A good example is shown of what happens if you accidentally hit the S key instead of grabbing the glass of orange juice that you were aiming for :doh:

 

3. Loss of aircraft no.2 was essentially deliberate. I wanted to see exactly how much G I could pull before airframe destruction. Turns out it's quite a lot, even at nearly 100% fuel.

 

Anyway, general constructive criticism is welcome...

Is this the correct track? You make 3 flights, not 2 but I only get to see the first 2 because, unfortunately, the track plays back incorrectly for me. I only get to see the first and most of the 2nd flight. You crash land short of the runway at the end of the 2nd flight. I don't get to see the 3rd, though. According to the log, there was a 3rd flight made by "KP Su-27 Standard" which never reappeared after the crash (yes, I let the track play to the end). Didn't see any issues in those first two flight. So I'm guessing the issues were in that 3rd flight.

 

Enjoyed watching you fly, by the way. That zoom climb really demonstrates the difference between IAS and TAS. Very odd to see your IAS at 80 k/h, while your TAS was 730 k/h and Betty is calmly chiding: minimum speed, minimum speed. And I've never seen the "own aircraft" icon on the HDD with its wing length spread so far across the HDD's bottom. :)

[DarkFire]

Is this the correct track? You make 3 flights, not 2 but I only get to see the first 2 because, unfortunately, the track plays back incorrectly for me. I only get to see the first and most of the 2nd flight. You crash land short of the runway at the end of the 2nd flight. I don't get to see the 3rd, though. According to the log, there was a 3rd flight made by "KP Su-27 Standard" which never reappeared after the crash (yes, I let the track play to the end). Didn't see any issues in those first two flight. So I'm guessing the issues were in that 3rd flight.

 

Enjoyed watching you fly, by the way. That zoom climb really demonstrates the difference between IAS and TAS. Very odd to see your IAS at 80 k/h, while your TAS was 730 k/h and Betty is calmly chiding: minimum speed, minimum speed. And I've never seen the "own aircraft" icon on the HDD with its wing length spread so far across the HDD's bottom. :)

 

Thanks :) That is the correct track but unfortunately it seems to be bugged. Trying to play it back again does indeed result in me apparently crashing short of Pashkovsky alternate whereas in actual fact I landed and taxied all the way over to the primary runway area. I then took off again and shortly afterwards tested the G-loading beyond the point of no return... The control sensitivity problem happened with the 3rd flight.

 

The zoom climbs are fun & the view from up there is amazing! I guess that at the top of the climb the wings generate so little lift that most of the altitude increase is due to engine thrust. It's also very interesting that very soon after the aircraft noses over, IAS is shown as ~100 - 175 and it's already supersonic!

[Ironhand]

...It's also very interesting that very soon after the aircraft noses over, IAS is shown as ~100 - 175 and it's already supersonic!

Guess that's a pretty good indication of how thin the air is at those altitudes... :)

[DarkFire]

So, the plot thickens.

 

The same control sensitivity happened to me today, but being ready for it I carefully checked out what was happening. Control surfaces were undamaged and working normally. I hadn't over-stressed the airframe so there shouldn't have been any unseen airframe damage.

 

What I did notice was this warning light:

 

 

According to page 45 of the Su-27 flight manual this warning light is the "ACS reset" warning, which if I'm reading it correctly means that the aircraft was under ACS control but that input had exceeded 20% control surface deflection which resulted in the ACS switching off and entering manual control.

 

The thing is, I hadn't been using the autopilot.

 

Now I'm even more confused :huh:

[Ironhand]

Hmmm...I noticed that you had one of the AP functions on during the 2nd flight of the track you uploaded. Was that intentional?

 

Perhaps it's time to check your key bindings.

[DarkFire]

Hmmm...I noticed that you had one of the AP functions on during the 2nd flight of the track you uploaded. Was that intentional?

 

Perhaps it's time to check your key bindings.

 

I think I'd been using altitude hold mode at some point, but I always turn it off when I don't need it any more. Hmm, sounds like I do need to check my key bindings.

[Ironhand]

I think I'd been using altitude hold mode at some point, but I always turn it off when I don't need it any more. Hmm, sounds like I do need to check my key bindings.

Hopefully it's something simple like that. Don't know if that's the server you were on both times this happened or not but I spent some time on that server yesterday crashing/restarting and simply restarting and nothing odd happened. No proof of anything, of course.

[DarkFire]

In further testing, both MP and SP, I've been totally unable to reliably reproduce the observed control behaviour. I even tried deliberately exceeding the control limits on the altitude hold ACS mode, but that didn't do it either.

 

I had an inkling that maybe this might have something to do with my abysmal internet connection, but then DCS doesn't appear to use a server-authoritative multiplayer model, so I'm at a loss.

 

Without being able to reproduce the issue I think I'm going to chalk this one up to 'weird stuff that happens online' and leave it at that.

[Ironhand]

In further testing, both MP and SP, I've been totally unable to reliably reproduce the observed control behaviour. I even tried deliberately exceeding the control limits on the altitude hold ACS mode, but that didn't do it either.

 

I had an inkling that maybe this might have something to do with my abysmal internet connection, but then DCS doesn't appear to use a server-authoritative multiplayer model, so I'm at a loss.

 

Without being able to reproduce the issue I think I'm going to chalk this one up to 'weird stuff that happens online' and leave it at that.

:) Perhaps someday we'll stumble onto the reason.

[DarkFire]

Well, I've managed to partially resolve the issue: the unusually high sensitivity is cured by resetting the ACS (alt-9), though I still haven't been able to find what causes the issue in the first place. I experienced it again tonight during takeoff on the VA server. This time the problem manifested itself as extreme un-commanded right roll which was cured as explained, but again I hadn't been using the ACS during the flight.

 

I did observe that when the control issue first appeared the ACS reset warning light illuminated red, though again I hand't been using it. Very strange but also quite infrequent bug.

[Ironhand]

Well, I've managed to partially resolve the issue: the unusually high sensitivity is cured by resetting the ACS (alt-9), though I still haven't been able to find what causes the issue in the first place. I experienced it again tonight during takeoff on the VA server. This time the problem manifested itself as extreme un-commanded right roll which was cured as explained, but again I hadn't been using the ACS during the flight.

 

I did observe that when the control issue first appeared the ACS reset warning light illuminated red, though again I hand't been using it. Very strange but also quite infrequent bug.

Sounds like it's one of those oddities like the lock tone you sometimes get, when you enter the cockpit.