Hi All,I've noticed in certain aircraft downloads, that when you activate the Autopilot, the pitch trim starts to automatically travel around. (This is only some aircraft mind,) This can sometimes have the effect of pitching the nose up way to early on a takeoff, (E.G. when wanting to use the AP auto throttle & LVL)Personally i prefer to manage the trim manually. Does anyone know what params in the air file or cfg file, need to be switched 'off' to stop this annoying problem?TaAl.

Al: Many aircraft autopilots (I'm sorry I'm not technical enough to know exactly which ones) use elevator trim to control the aircraft pitch. That's why, I'm pretty sure, you're seeing the trim control move. Also, I did not think autopilots were used until something like 400-1000 feet AGL and not normally used for takeoff. I think the TO/GA button (take-off/go-around) is the closest thing to a takeoff autopilot. Sorry I could not be of more help.

You could try using the autopilot without using the altitude setting, since this is the one that would want to adjust the trim. That is just the way the autopilot works, since the only way the AP can maintain a specific altitude/pitch/VS is by adjusting the trim. Also, on some aircraft the auto-throttle setting might be used on take off, but I don't think the full autopilot would be used normally.- Martin

If you have saved and then use a plane / situation for your default startup and you did so with AP on, you will see this in some a/c. The solution is to resave your situation/plane without AP on and use that as the default startup. That way, if you change to a plane that demonstrates this effect, you won't have that abrupt surprise at take off. And, you will be using the AP it was supposed to be used; turning it on only after wheels up. :)

use_no_default_pitch=1 under the A/P settings in the aircraft.cfg....use_no_default_bank=1 is useful if you want manual directional control while the A/P is engaged....-John

Just last night I watched a cockpit video or a 727 taking off. The aircraft was barely off the ground when the autopilot was engaged and the elevator trim wheels were spinning like mad. There's a link to this and other videos in a post yesterday in this forum.David

Hi JohnI'll give your answers a try.However just to clarify to all other people what I'm seeing.Sometimes... & only sometimes. it depends of the plane..I can be sitting on the tarmac ready to go, or even just parked.I hit the AP button only, NOT any of the other functions like alt hold etc, JUST the AP button, & the TRIM starts to travel all by itself!!!?Do the same thing again in a different plane, Activating the AP does NOTHING! except when i tell it to do something.. It is this that i want to configure in ALL aircraft..I'll try the above suggestions though as well..Al.

BINGO!!!Adding:use_no_default_pitch=1to the cfg file, fixes the prob, indeed after examining some of the aircraft that were showing the problem, ALL had the above line MISSING from their cgf files.Thanks for the helpRegardsAl

AlSorry I misunderstood your origional problem. Glad you got it straightened out and thanks for posting that cfg line. I think it will fix a different AP problem I have.David