1.2.12: Su-27 PFM trim issues with FFB / thrust on ground is very strange

First off, the problems I describe has been in DCS since the Su-27 got it's new PFM. I've "reported" (not proberly, therefore the quotation marks) them several times in the changelog threads, but noone could concur, probably because of their lack of FFB hardware. So I've done a track now to show what's happening. I hope it's ok to report 2 issues in one thread, as one tracks shows them both

My main bug statement is, that the trim doesn't work properly, or rather it's not effective enogh. At full forward trim, I still have to push my stick further forward, to stay level. Basically I can't trim the Flanker so it flies with no stick force. Just for understanding the problem: On FFB sticks in most planes the trim "just" moves the stick force center point, but it's limited to like 60-70% of the travel to each direction, so you can't trim it until the center is at full deflection which probably is the reason for this issue. I haven't checked with disabled FFB, but I think the trim can be pushed forward far enough in that case as no other reports on faulty trim can be found.

The other one is the thrust ratio on the ground. It is virtually impossible to control taxi speed with the throttle. Either the Flanker is standing still/slowing down until it stands still, or it literally rockets up to 100+km/h extremely fast. The threshold is approxiamately at 78-80% rpm.

Short note: I double checked all my mappings, nothing's bound twice, all curves are linear.

Track description: I load up some AG stuff, taxi out of my shelter, get too fast, try to catch the corner, bam, one tyre broken - repair - proceed to take off. I trim fully forward on the runway, have to pull back to get her off ground, but after that I already have to push forward a little bit to keep her from pulling up even more though I initially climb at a very low speed. Heading eastwards to attack some AA stuff located next to Kutaisi Airport (not the AFB), first boming stuff with RBKs, then throwing some S-13 and finally doing gun runs. Somewhere in this action, I switch on the control window (don't know if it shows up in track), and it's easy to see how I struggle with the control to aim at the SAM/AAA sites. After beating them anyway, I head off to the west and at one point, still being trimmed fully forward/nose down, I just neither pull nor push the stick at all, keeping the pitch at where FFB centers it. Just rolling around several times to show that with full nose down trim the Flanker still does 4+G turns without any pitch input. I might add that all stick action takes place in the foremost ~20-30% of the stick movement zone. After landing, I just give short but hefty bursts of thrust to taxi - works quite well but can't hold the taxi speed at all.

Just on a side note: I'd very much appreciate to have a wheel brake axis fir the Flanker...

The thrust is more or less working as intended. At about 80% throttle when increasing thrust, or at about 72-74% throttle when decreasing throttle from above 80% the nozzles on the engines close/open.

When they close, the thrust increases greatly. This is supposed to reflect the real behavior of an Su-27's engines.

Happens on the ground and in the air.

For taxiing you just have to anticipate. Throttle up to 80%, and after half a second or less, throttle down to 70%, even if you haven't started to accelerate to a large amount. If you wait until you see the acceleration, you'll have more than you want, as it takes a few seconds for the engines to spool back down after you reduce throttle low enough to cause the nozzles to open.

The other FFB stuff I know nothing about, but a lot of people have had trouble with the 27's trim.

I can confirm the same issue with trimming. I use the Logitech G940 and I have full forward trim and I am constantly fighting to push the nose down. I can tell that it does do something, it's just no where near enough for straight and level flight. This is at all speeds.

same here,

su-27 trim does not work at all for me. When I tried trim, ''Trimming lights neutral position indicator'' light goes off, but on ''Show controls indicator'' you can see absolutely nothing happens and have constant strong nose up, which make very unpleasant fly.

btw. i have mig-21 too, and everything works well here

edit

Seems, it is FFB issue, i switch off FFB and trim works

Same, same. In fact, I just exited the game and came here to see if this is part of her FM.

funny enough, i tested also Mig-29, and trim does not work too while FFB on

I can confirm the same issue with trimming. I use the Logitech G940 and I have full forward trim and I am constantly fighting to push the nose down. I can tell that it does do something, it's just no where near enough for straight and level flight. This is at all speeds.

try to uncheck swap axis and decrease the trim force to %30.

i have g940 and with this setting i have no noseup problem.

this problem depends on joysticks which has ffb function.

try to uncheck swap axis and decrease the trim force to %30.

i have g940 and with this setting i have no noseup problem.

 

this problem depends on joysticks which has ffb function.

tried that, does not work in my case :(

I'll try that and let you know. It would seem if I turned it down it would trim even less.

The issue isn't exclusive to FF stick, btw. I use a Logitech 3D and I can't trim her at all.

I use the warthog and trim works fine. I use it all the time... And I have been just flying the flanker for 7h of sim time since 1.2.12 was released.

I use the warthog and trim works fine. I use it all the time... And I have been just flying the flanker for 7h of sim time since 1.2.12 was released.

+1

i have very stable flights with trim as usual and yes 1.2.12 corrected most issues for stability.

+1

i have very stable flights with trim as usual and yes 1.2.12 corrected most issues for stability.

For sure. I think in 1.2.12, there is a default "nose down" trim applied to the aircraft after you resume it from pause state, this is perfect enough that at the given speed, the aircraft will fly level and very stable.

Ok then did I miss something? A button or two? This patch screwed some thing up for us. I must have maxed out the trim and she still wants to do a cobra.

Ok then did I miss something? A button or two? This patch screwed some thing up for us. I must have maxed out the trim and she still wants to do a cobra.

Considering your join date I suppose you tried :

Rctrl + Enter to check trim controls if the cursor actually moves with the trim?

if not then check keybinding

Have you selected the right profile?

if so,

TRIM MORE....:joystick:

else,

try repairing using the command line dcs_updater.exe repair 1.2.12.

Backup saved games file, delete, and let DCS World recreate it?

or last resort re-install the modules.

ALSO...try resetting your trim with CTRL + T. Double check the key commands for the trim. I actually set my nose up/down/left/right trim to the hat on the warthog stick.

Nyet. That did not occur to me and I am ashamed.

Having said that, this is more along the line of what I originally thought of: http://forums.eagle.ru/showpost.php?p=2256940&postcount=3.

Basically, you approach trim differently with the Su ACS system. What you want to do is settle at your desire speed then trim AOA. I'm at work but will let you all know as soon as I'm home.

EDIT: Trim definitely work. I'll try repairing.

seems some people do not bother read previous comments. There is clearly stated ,trim does not work while FFB on, - anyway they give you a briliant advice ,trim more!!!,

With FFB, trim works well for me too.

1.2.12 is perfect update:)

seems some people do not bother read previous comments. There is clearly stated ,trim does not work while FFB on, - anyway they give you a briliant advice ,trim more!!!,

May I ask what you added to the matter? In terms of constructive thinking or advice?

We have read. On top of that it appears so, we managed to figure out his problem.

Your 'brilliant' comment is time that could have been better spent elsewhere.

There is clearly stated ,trim does not work while FFB on

this problem changes which depends on joystick and user configuration. not a certain problem for everyone.

seems some people do not bother read previous comments. There is clearly stated ,trim does not work while FFB on, - anyway they give you a briliant advice ,trim more!!!,

This statment : "There is clearly stated ,trim does not work while FFB on" is not actually true.

It may be may be true for you, but you state it as universally true, and it is not universally true.

I have an FFB stick, and it works correctly, theropod has a FFB stick and it works correctly.

While JulienBlanc might have jumped the gun saying 'we've figured it out', his point was that most of the complaints about trim do seem to have ended up being incorrect setup or incorrect expectations about operation, rather than actual bugs.

If you want to post some screenshots of how you have your controller configured, I'll do the same & we can see if there are obvious differences.

I retract my earlier post as I do not have trimming problem; I need a new joystick is all. Joystick pots spiking like crazy.

I tested at 30% trimmer force and it is still garbage. Pulls up constantly at all speeds.

I also disabled the force feedback completely in game and the 27 flies like I would expect it to fly. Nice and level once trimmed out. Granted I personally think the trimmer speed is to fast but this may be how fast the real 27 trimmer moves.

1.2.15 and still having this.