Running Out of Elevator Down Trim at 800 KMH

I noticed that 800 KMH true at any altitude that I hit the limit of elevator down trim

Is that a limit of the sim or the Flanker?

Cheers,

Lucky

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Are you using FFB? With FFB it is worse, some say broken. The Su-27s FBW is designed to mimic a stable aircraft that pitches up when faster than cruise speed. With normal sticks I’m always able to trim enough but with FFB the stick is almost always trimmed all the way down unless I need the elevator authority, kind of annoying but I think it’s worth it for the joy of FFB.

I've asked this before, but are you sure you have no axis curves or reduced saturation set up, or FFB mods installed ?

MSFFB II

Tried M2 at 10,000m (2002 km/h TS) - no problem trimming to level and still room to trim to a dive.

Dove to 2000m & levelled out - M1.3 (1400 km/h IAS, 1547 km/h TS) still no trouble trimming to nose down...

I noticed that 800 KMH true at any altitude that I hit the limit of elevator down trim

 

Is that a limit of the sim or the Flanker?

 

Cheers,

 

Lucky

 

 

Sent from my iPhone using Tapatalk

At lower altitudes (2000 m, for example) you seem to lose nose down trim authority from around 800 IAS to roughly 1000 IAS (roughly M 0.75-0.9). Outside of that range you're fine. Inside that range, trim seems nearly neutral but slightly nose up. This only occurs with the FBW sytem engaged. Disengaged, there's no such limitation. I've never noticed that null range at higher altitudes (eg: 10K m). EDIT: As Weta43 notes, trim authority is there at higher Mach numbers. I've been up to around M2.3 or 2.4 without trim issues. And at high altitudes, there are no issues in that M 0.75-0.9 range. There is still plenty of nose down trim available in that range. ::EDIT ENDS

Don't know if that's the case with the real deal as well or not. But I notice that the intercept flight profiles from the real world manual call for climbing to high altitudes.

I got an old FFB stick.

That is why I have trim authority on Su-33

And the Flanker feels limited.

Hopefully fixed soon now if the stuttering in the Persian Gulf is fixed that will be great

But I can fly and fight with an 800 KMH restriction for the flanker

Thank you for the info

Lucky

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For giggles my dead zone is 5 and the elevator axis is 30

Lucky

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I got an old FFB stick.

 

That is why I have trim authority on Su-33

 

And the Flanker feels limited.

 

Hopefully fixed soon now if the stuttering in the Persian Gulf is fixed that will be great

 

But I can fly and fight with an 800 KMH restriction for the flanker

 

Thank you for the info

 

Lucky

 

 

Sent from my iPhone using Tapatalk

Just came back to mention one other thing. That null zone I spoke of in my previous post depends on the fuel quantity (and resultant CG, I think). With full fuel, for instance, the null zone is very narrow centering around M0.9. With other fuel quantites, you'll see it expand or contract and wander a bit...I suspect it's tied to slight shifts in the CG as fuel is drawn down in sequence from the various tanks.

Took out the dead zone to 0 and No curves in the Pitch Axis (Elevator axis)

And my Flanker is a warplane possessed!

I have trim authority again but a bit touchy in pitch at first for landing but got used to it

Awesome plane

Too bad I was fighting the FCS all the time for a year

Thank you for the advice

Lucky

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Just came back to mention one other thing. That null zone I spoke of in my previous post depends on the fuel quantity (and resultant CG, I think). With full fuel, for instance, the null zone is very narrow centering around M0.9. With other fuel quantites, you'll see it expand or contract and wander a bit...I suspect it's tied to slight shifts in the CG as fuel is drawn down in sequence from the various tanks.

There's another strange behaviour associated with the null zone: at the onset (nearly exactly 0.9M with full fuel) the roll channel no longer self-centers as it normally does. This behaviour continues at all speeds above 0.9M whereas the trim authority returns when speed exceeds about 0.95M, again with full fuel at low (<200m) altitude.

Took out the dead zone to 0 and No curves in the Pitch Axis (Elevator axis)

...

I have trim authority again but a bit touchy in pitch at first for landing but got used to it

 

Awesome plane ...

It is an awesome plane. You can probably put a bit of dead zone back in, if you like. I normally have it at "3". Tried "0" and there was no difference as far as that null zone is concerned. Are you getting something different? But, then again, my stick isn't FFB.

There's another strange behaviour associated with the null zone: at the onset (nearly exactly 0.9M with full fuel) the roll channel no longer self-centers as it normally does. This behaviour continues at all speeds above 0.9M whereas the trim authority returns when speed exceeds about 0.95M, again with full fuel at low (<200m) altitude.

I wonder if the roll issue has to do with increased pressure on the control surfaces at higher speeds. Just a thought.

https://forums.eagle.ru/showthread.php?t=217228

Its the same problem thats with all aircraft but it appears worse in the su-27. Nobody is interested in fixing it though :(

...Yes, it is the same for all aircraft - curves are not supported with FFB and if you add them you will break the FFB.

When you say "Nobody is interested in fixing it" - as it's not supported, it's not broken... so it's not a bug, it's a feature request.

That said - FFB users are a small proportion of users, but as one, it would be a good feature to add for us.

Nothing different

Just personal preference

Cheers,

Lucky

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I wonder if the roll issue has to do with increased pressure on the control surfaces at higher speeds. Just a thought.

Almost certainly. The automatic roll neutralisation stops at all altitudes when speed approaches the transonic region. Given that it appears to happen at ~0.9M rather than a fixed IAS or TAS I would surmise that it is increased pressure on the control surfaces but likely due to the formation of transonic shockwaves rather than simply increasing dynamic air pressure. I'd imagine it may be entirely deliberate in order to avoid any uncommanded forces on the airframe in the transonic region of the G/mach envelope.

...Yes, it is the same for all aircraft - curves are not supported with FFB and if you add them you will break the FFB.

 

When you say "Nobody is interested in fixing it" - as it's not supported, it's not broken... so it's not a bug, it's a feature request.

 

That said - FFB users are a small proportion of users, but as one, it would be a good feature to add for us.

Sorry, yeah you are right its just annoying when it makes some aircraft near impossible to fly. If you could push this feature request forward that would be appreciated ;)

...Yes, it is the same for all aircraft - curves are not supported with FFB and if you add them you will break the FFB.

 

When you say "Nobody is interested in fixing it" - as it's not supported, it's not broken... so it's not a bug, it's a feature request.

 

That said - FFB users are a small proportion of users, but as one, it would be a good feature to add for us.

I wouldn't say that the FFB community is small... have you seen the latest thread in the official news section ? The amount of people that have M FFB2 amazed me....

Sorry, yeah you are right its just annoying when it makes some aircraft near impossible to fly. If you could push this feature request forward that would be appreciated ;)

+1

I wouldn't say that the FFB community is small... have you seen the latest thread in the official news section ? The amount of people that have M FFB2 amazed me....

Same I thought I was in the minority of an already small niche, I'd love to be able to trim my helicopters and planes properly

... have you seen the latest thread in the official news section ? The amount of people that have M FFB2 amazed me....

Yes, me too

I thought I was in the minority of an already small niche

Yes, me too

I’m not technologically savvy

Is the A10 stick/ cougar advanced joystick an FFB or a regular stick

Cheers,

Lucky

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