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

1.2.15 and still having this.

+1

http://forums.eagle.ru/showpost.php?p=2335061&postcount=62 :doh:

Is there any chance to happen or do I have to switch over to a HOTAS Warthog to "fix" the FFB issue? ;)

#mostrecentver

As I said before, if you're having trouble with FFB it's most likely one of 2 things:

1/ Your setup - as it works perfectly with my MSFFB II & the majority of other FFB users.

2/ Your stick isn't trully FFB, just FFB augmented (don't have time to troll back looking for what stick you have).

Please make sure the answer to all the following is 'Yes" :

Do you have FFB turned on inthe Axis tune section ?

Have you checked the 'swap axis' box in the FFB setup interface ?

Do you have your curves set to straight ?

If you're sitting hot but stationary on the runway and you trim the nose down, does the stick actually move forward ?

Was it ?

Eldur, which ffb stick do you have? It works OK with the msffb2.

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.

Nope!

Did you see the Wags during the taxi to the runway with the new angine?

He never needs to brake or must work, like we must do right now, very much with the power.

The Su27 power behavior is wrong atm.

Wags was mostly at 74% power and the plane wasn't accelerating like it does right now. Atm you must throttel over 78% and later close the power to not get too fast and that time after time to hold a steady taxi speed.

This is not necessary in a real Su27!

Even in the air Wags wasn't loosing so much speed like we do right now.

I can't wait to test the new engine.

It looks like they have done many work to the PFM too.

As I said before, if you're having trouble with FFB it's most likely one of 2 things:

1/ Your setup - as it works perfectly with my MSFFB II & the majority of other FFB users.

2/ Your stick isn't trully FFB, just FFB augmented (don't have time to troll back looking for what stick you have).

 

Please make sure the answer to all the following is 'Yes" :

 

Do you have FFB turned on inthe Axis tune section ?

Have you checked the 'swap axis' box in the FFB setup interface ?

Do you have your curves set to straight ?

If you're sitting hot but stationary on the runway and you trim the nose down, does the stick actually move forward ?

 

Was it ?

My stick is the good old trusty MS FFB2, and I've got 3 of 'em that all show the same behaviour. All questions answered "yes", but in flight, max trim nose down, stick held in FFB center, the plane pitches up at all speeds over ~400-450kph still even in 1.5 OB. Just did a check with the most recent version.

Regarding the engine/thust issue, I'm with Nedum, and as we're at 1.5 OB already, these changes are noticable which makes this issue fixed :)

I got the same flight stick, Microsoft Sidewinder Force Feedback 2.

The trim on F-15C and Su-27 is not working when FFB is turned on.

I managed to get it trimmed to some extent (I played with FF tune and axis curves etc...), but it refuses to trim all the way like when the force feedback is off.

Is there a settings in the config files in installation folder we are missing?

Do developers know about this issue?

So, could you do 2 things.

Set everything back to default (no curves 100% feedback, no inversions or axis swapping etc.) & FFB on, but set the shake forces to zero.

On the ground, just cover the light sensor on the stick with your finger so the FFB is activated (If leanning over it should snap into place at this point) - don't actually hold the stick in one place.

If you trim the nose down, does the stick move forward, backwards or sideways ?

It should go forward, so if forward go to the next paragraph. If backwards invert the forces & if sideways swap the axis. If it doesn't move at all - you're not using FFB.

Please re-test in flight.

If the FFB / trim is working as expected above, at takeoff, when you retract the gear and flaps stabilise your altitude & speed at 400 km/h.

The nose should now require a fair bit of trimming down to achieve level flight without having to actually push forward on the stick. The stick will now be sitting forward of center & should stay there if you let go of the stick but cover the sensor.

Can you trim to level at a constant 400 km/h ? If you just cover the light sensor, where does the stick sit ?

Now increase speed to a steady 500 km/h. The plane should again require the nose trimming down & the stick will sit slightly further forward.

Can you trim to level at 500 km/h ? where's the stick sitting now ?

At what speed can you no longer trim the stick forward enough to achieve level flight at a constant speed ?

I'm sure you already know, but if you increase speed after trimming, you have to re-trim. Nose down as you speed up, up as you slow down.

Please describe again what it is you're actually experiencing (does the stick move, but not enough ?, and what you believe should be happening (or better still if you have shadowplay/fraps or the equivalent upload a short video).

Hey Weta,

It works now, thank you!

One question, can we use curves when FFB is enabled? Or the curves will mess things up?

No problem.

I can't remember (I've never used curves on any module except to check they work), but thinking about it now, I'd imagine that during trimming the interaction between the linear forces of the FFB and the non linear responses of the joystick using user curves might be quite trick to resolve to an intuitive set of stick responses...