Integrated Trim System

[WinOrLose]

In the NATOPS manual (B) it references an Integrated Trim System, The ITS is incorporated to eliminate longitudinal trim changes
caused by the extension and retraction of flaps and speedbrakes.

At present when extending flaps you need to counter with about 5' of pitch down, I accept it doesnt reference DLC, but this then requires approx 2' pitch up. It makes for fun and games for the wingman in a pairs recovery.

Is there anychance of this system being implemented?

 

Thanks.

[sLYFa]

ITS is already implemented, you can see the pitch trim change as you extend/retract flaps. The system is not perfect though so you still need to trim by hand. As for the speedbrake, IRL the ITS would trim a bit TED when the speedbrake came out to counter the small pitch up moment the speedbrake creates. In DCS this used to be somewhat implemented but due to the very complex aerodynamics involved, it wasnt perfect and created problems on other, more important ends. The workaround right now is that the speedbrake in DCS does not create any pitching moments (unlike IRL) that the ITS would need to adjust for. So FM wise it is correct but you wont see the stabs moving down a bit when deploying the speedbrake. 

Edited August 5, 2022 by sLYFa

[WinOrLose]

Cheers - I'll take a look at the trim guage next time - my eyes are usually elswhere.

[WinOrLose]

On 8/5/2022 at 2:38 PM, sLYFa said:

ITS is already implemented, you can see the pitch trim change as you extend/retract flaps. The system is not perfect though so you still need to trim by hand. As for the speedbrake, IRL the ITS would trim a bit TED when the speedbrake came out to counter the small pitch up moment the speedbrake creates. In DCS this used to be somewhat implemented but due to the very complex aerodynamics involved, it wasnt perfect and created problems on other, more important ends. The workaround right now is that the speedbrake in DCS does not create any pitching moments (unlike IRL) that the ITS would need to adjust for. So FM wise it is correct but you wont see the stabs moving down a bit when deploying the speedbrake. 

 

So just to clarify - should we see the trim physically change in the dial as I'm not seeing that?

[sLYFa]

Yes it should. But its just a couple of degrees NU when deploying the flaps. For the speedbrake, the stabs wont move since this part is not fully implemented yet. 

[WinOrLose]

Thanks - I have not noticed the trim up on the last couple of flights, maybe one of the patches messed with it? 

Maybe the same thing with DLC, NATOPS suggests that deploying DLC on speed should not result any any pitch change but I'm getting a definite nose down.

[Northstar98]

On 8/7/2022 at 12:30 AM, sLYFa said:

Yes it should. But its just a couple of degrees NU when deploying the flaps. For the speedbrake, the stabs wont move since this part is not fully implemented yet. 

I swear this used to be implemented though, I can't remember which update it was (perhaps the one which introduced the A?) where deploying the speedbrake stopped adjusting the trim.

Edited August 8, 2022 by Northstar98

[sLYFa]

The speedbrake induced trim was indeed there at release but was remove about half a year ago later IIRC since it caused too much TEU trim requirement in the landing configuration. The compromise HB did back then was to remove the speedbrake's pitch up moment and the associated ITS function. 

[JupiterJoe]

When on the ground/ship the plane currently trims all teh way aft when you activate the AP.  You can watch the stick move all the way aft.  Is it supposed to do that?