Trim

[severniae 78]

Hi all,

I've noticed for the first time (after many years simming!) That if I trim back, I lose full forward elevator effectiveness, and the same vice versa trimming full forward.

 

This hasn't been an issue until I got a Brunner FFB yoke which ignores the internal trim position and does its own thing.

 

Does anyone know how I can get full range of elevator motion without having to move the in-sim trim? 

 

Help greatly appreciated,

James

[flyforever 267]

I'v experienced this phenomenon in some aircrafts, rather than the sim in general.

So, I suggest that you try different aircrafts and determine if the trim issue is the same across all aircrafts.

The biggest offender is a specific payware aircraft in x-plane. I cannot trim and have sufficient elevator action in the yoke on touchdown. This forces me to fly with the yoke and pulling back on it.

tony

[Biggles2010 342]

I think you will find in P3D, and FSX before, that the trim function in most aircraft is implimented through the elevator, rather than as a seperate control function. So it acts like moving the elevator which will affect the ranges of movement in both directions. More specialised payware models may have different ways of achieving trim effects. If you are having a problem with a particular aircraft you can try increasing the range of elevator movement by editing the controls section in the aircraft config file. Backup the file first then make small changes and test the effect.

 

[C2615 319]

If the aircraft use different control surface for trim (most likely, whole stabilizer as on most airliners), it will reduce the "effective" range of elevator.

[jcomm 5,890]

FSX, previous versions, and ESP / P3D do not model Elevator trim. Instead they model "stabilator" trim, as in most airliners. The elevator itself doesn't move, as if it had a trim tab. OTOH the other trimmable surfaces do kind of simulate the trim-tab approach, although they deflect irrespective of there being or not any significative dynamic pressure ( meaning they will move as you apply trim even if you're standing still on ground, if on a prop aircraft with the engine shutdown to factor out any propwash effects, and even at zero wind... it's a simplification that still exists in the new MFS... ).

From Yves "Filght Dynamics in MSFS" you get:

"4.1 Elevator and Pitch Trim The main pitch control system in MSFS consists of an elevator and a stabilizer trim surface. The pitch trim concept is basically more the one of a moving horizontal stabilizer than that of an elevator with trim tabs. However, the additional lift and drag generated by the deflected stabilizer is not simulated in MSFS. Furthermore, the default autopilot only uses the stabilizer for trim and not the elevator. For consistency with the SDK the term Cm_detr is used although the elevator is not directly involved in trim. 
 
MS seems to have pitch controls designed for joysticks where the stick returns to a fixed center when hand force is released (such as most game sticks, e.g. Saitek X52). Zero hand force means zero elevator deflection in relation to stabilizer, so the stabilizer is the only trim surface. "

Probably your FFB yoke uses some built-in driver / filter that assumes an "elevator trim" mode instead, and thus translates it into a 

[severniae 78]

So I've tried a number of settings in the aircraft.cfg, but on the PMDG DC6, when moving the trim it moves the range of the yoke and it doesn't appear there is any way to get around it.

Same story on nearly all the other aircraft too, unfortunately.