Trimming the SU-25T

[coolts]

Compared to the basic FM planes this thing needs bucket loads of trim, but that’s okay, because trimming is free and legal!

Can someone tell me the meaning of the 3 trim lights (green) in the bottom centre of the cockpits [below].

I noticed them last night. Are they pitch, roll & rudder trim indicators?

Edited March 2, 2010 by coolts

[bengo]

Yep, they are. They light up whenever the trim for that axis is in its neutral position.

[71st_Mastiff]

Compared to the basic FM planes this thing needs bucket loads of trim, but that’s okay, because trimming is free and legal!

Can someone tell me the meaning of the 3 trim lights (green) in the bottom centre of the cockpits [below].

I noticed them last night. Are they pitch, roll & rudder trim indicators?

 

your trimmed and stable.

[S77th-konkussion]

Wait'll you shoot off something heavy. Opens up a whole new world of trim issues. Get to know the many auto pilot modes, and have them readily available on your HOTAS. They come in handy.

[HiFly62]

Not necessarily, it only means that your trim surfaces are in neutral position. You could have a 25ML and a 25MPU on your left wing with the three green lights - far from being stable or trimmed.

[S77th-konkussion]

My comment had nothing to do with the lights, neccessarily.

Edited March 2, 2010 by S77th-konkussion

[EtherealN]

I think he replied to GF_Mastiff, unless you believe he read your post AND typed his response AND managed to press the post button in less than 60 seconds. ;)

[HiFly62]

Actually I've responded to GF Mastiff's post.

[71st_Mastiff]

Actually I've responded to GF Mastiff's post.

 

ah ok

I always see them come on when i trim,

[HiFly62]

My comment had nothing to do with the lights, neccesarily.

 

Thanks for the spelling lesson.:thumbup:

[71st_Mastiff]

read this it was in the search thiingy.

 

http://forums.eagle.ru/showthread.php?t=6696&highlight=SU-25+SU+25t+trim+mode

[coolts]

Sorry to butt in guys, but the llights......mean neutral trim right?

[S77th-konkussion]

Thanks for the spelling lesson.:thumbup:

 

There is that better? I wouldn't want you to feel too superior in the midst of all of the unwashed masses.

[lennycutler]

Trim in the SU25T

 

My key mapping to reset the trimmers is Ctrl T, but I do not notice the trim light indicators returning to Green when I press Ctrl T.

 

Is there some magic to getting the Trim to Reset in this aircraft?

[Ike4fin]

My key mapping to reset the trimmers is Ctrl T, but I do not notice the trim light indicators returning to Green when I press Ctrl T.

 

Is there some magic to getting the Trim to Reset in this aircraft?

 

Trim reset doesn't work in SU-25 but you can use level autopilot(alt-3) to get it in stable trim.

 

Heres nice tutorial for it:

http://lockon-greece.forumotion.net/forum-f8/topic-t52.htm

[coolts]

Gaaa! Ive been battling with my HOTAS for the last half hour trying to get the trim reset to work on this!

[104th_Crunch]

Again, trim reset doesn't function on the the 25(T) as the real plane has no such function. You manually trim and you always work from your last trim point. You will find that you never miss a reset function.

[159th_Viper]

Do yourself a Favour and Map the 'Emergency Levelling Mode' to your HOTAS [Alt-3].

 

Trims the Toad for the specific Flight Parameters at time of Engaging Mode. Useful as a Sort of 'Quick-Trim' function.

[coolts]

<Viper> does that alter the trim? I've been fighting the SU-25T instant action scenario for days now and am flailing about all over the place after a fire any ordnance.

If I trim to attempt to stabilize after firing an IR missile, (the weight imbalance immediately sends the wings over), then hit "emergency levelling", then need to shallow dive to strafe, (therefore cancel "emergency levelling"), will my previous trim send me out of control again?

My ham fisted fix to this ATM is to simply fire two A-A missiles at a time to maintain balance. A waste of Roubles!

I guess I am asking whether to avoid aileron trim if using "emergency levelling mode"

[coolts]

From Greek lomac website (admin "sisifos")

 

Cheers Ike4fin for pointing me at this one.

 

"There's 6 new Auto-pilot modes for the Su-25T.

The plane does auto-pilot by trimming itself with trim tabs to match the mode

required. On exiting most auto-pilot modes, the trimming is bound to be incorrect

and

you'll flop about. In the other planes you could cancel trim with Ctrl-T.

But for the Su-25T, you can get the correct trimming by choosing

the Emergency leveling mode(ALT-3), which puts you level and

straight, and then exiting auto-pilot altogether with ALT-9 or A.Overall,

when you use auto-pilot once, you have to use it forever more."

 

That clears that up. I need to map some more autopilot modes to the stick. :joystick:

Edited March 3, 2010 by coolts

[joey45]

<Viper> does that alter the trim? I've been fighting the SU-25T instant action scenario for days now and am flailing about all over the place after a fire any ordnance.

 

If I trim to attempt to stabilize after firing an IR missile, (the weight imbalance immediately sends the wings over), then hit "emergency levelling", then need to shallow dive to strafe, (therefore cancel "emergency levelling"), will my previous trim send me out of control again?

 

My ham fisted fix to this ATM is to simply fire two A-A missiles at a time to maintain balance. A waste of Roubles!

 

I guess I am asking whether to avoid aileron trim if using "emergency levelling mode"

 

If you know what side the missle/bomb is leaving from then you move the stick then trim...

[coolts]

I'm just wondering whether, as the autopilots in the SU-25T essentially set the trim for themselves, maybe it’s best to go one way or the other.

 

Either trim or autopilot.

 

After all with 6 or whatever autopilot modes you have essentially got macros to any trimming you would ever want

 

· hold attitude

· fly level

· hold bank

· hold alt baro

· hold alt radar

· cancel autopilot (and trim?)

 

…. and to manually trim as well will just confuse things leading to more problems as there isn’t a reset trim option

[Zorrin]

Well not really. How are you going to trim it for a descent or a climb if you are relying on the autopilot?

 

Just use them both together. As soon as you switch the autopilot off you'll know what sort of a "state" the aircraft is in, because you can let go of the stick etc etc. You really only need to trim to take the load of the stick, so that you can be hands off if you need to be.

 

Sure if you start putting the autopilot on when you are in extreme manoeuvres this will potentially cause you problems.

[159th_Viper]

coolts - Just a quick query:

 

Apologies if you have this covered, but ensure you have your Control (Pitch/Roll) Axis Inputs set to Linear. Transforms the Toad from a Hippopotamus to a Gazelle :D

[Sarge55]

What Viper said .... I had some curve in my axis inputs at first but the linear setting is the way to go.

 

Once the emergency level has stabalized you just turn it off again (kind of like a trim reset), it will not be perfect but I find it very close to trimmed.