FSF Trim vs. FSX trim - help me understand!

[MarkH]

I am happily flying with FSF and an Iris yoke, but I am still a bit puzzled by the interaction of FSX and FSF trim systems. Why do we need access to the FSX trim at all? I have noticed that it does affect the aircraft, so if I dial in full back trim (FSX) my FSF neutral trim position (yoke centred, trim value 0) is very nose-up. So far, so good - I can adjust the neutral attitude with the FSX trim control. I would normally not do this or need it, but I suppose it might com in useful.

However, what is going on when I use the autopilot? I notice the AP adjusting the FSX trim so how does FSF handle this? How does it leave FSX trim when I disconnect the AP? As far as I can tell, when on autopilot FSF is not doing anything and FSX is flying the aircraft. Assuming I do not have AP follow on, the yoke stays centred. But when I come off autopilot, I have a new neutral position determined by wherever FSX has put the trim setting. This can often cause a pitch departure (up or down), depending on that FSX trim setting.

If this is correct, FSF isn't really handing the autopilot at all - is that right? It just kind of relies on the trim being set to neutral when the AP is disconnected. Or, rather, it relies on the trim being where it was when the autopilot was engaged? If this is how it works, I can see a way to maybe fix it (I run my cockpit with LINDA and Lua scripts, so I could probably save and restore the FSX trim position when switching the AP on and off).

P.S. Is there a way to map the function of the SHIFT key (swap which trim we are adjusting) to a button rather than having to use SHIFT? I usually do not have a keyboard in my cockpit. Likewise, could we not have buttons for the FSF re-initialize and re-start functions?

[RussDirks]

> Why do we need access to the FSX trim at all?

Normally you don't. I just put that feature there for completeness.

> Likewise, could we not have buttons for the FSF re-initialize and re-start functions?

The documentation doesn't make it clear, and I'm not sure if I've ever tried it, but looking at my programming code, it should be possible to assign both of those functions to controller buttons.

[MarkH]

The documentation doesn't make it clear, and I'm not sure if I've ever tried it, but looking at my programming code, it should be possible to assign both of those functions to controller buttons.

Awesome! I just tried this and it works:

ReInit=Joystick:1:Button:20
Restart=Joystick:1:Button:22

[P.S. Health and safety warning: take care which button(s) you assign these to! Sitting on the ground and pressing either one causes the Iris yoke to shoot back to its centre position before FSF re-initialises.]