Aircraft lifts nose automaticly during takeoff

[digidax]

Stupid thing:
Waiting for departure release, aktivating transponder, speed up eninges to 50%, after reaching it leaver to FLX. Aircraft is moving on, holding it with rudder pedals straigt on the runway (side wind), on around 80 kt, aircraft takes nose up without any input from the sidestick. Result: tailstrike and simulation is finished. P3D reloads scenery. Staring exactly the same procedure from gate like before and now, not tail strike, moving back sidestick at calculated Vr = 139, and get airborne normally.

The last changed i made was updating AIRAC to 1703 and Scenery naviaids too, regenerating *.bin files and distribute them to the ND PC's.
Controller settings in P3D are disabled, settings for pedals and sidestick in FMGS config is also set correctly.

Any ideas?

best regards, Frank

[Hypnorm]

Check your elevator trim.. for a while I was getting full trim 13.5 for no apparent reason.

Unfortunately, I can't remember what I did to fix it ..... it may have gone away on its own, but it may give you a start.

H

[digidax]

Yes, this could be the result of disabling the auto trim function of Skalarki because this issue here:
http://www.mycockpit.org/forums/showthread.php?t=31286&p=166474&viewfull=1#post166474

Now the trim wheel is not actuated but during the flight, the FMGS adjusting works and can be monitored on the FCTL page.
So before takeoff I have checked the elevator trim is 0. And after the tailstrike I have check it again and have moved the trim wheel manualy. So maybe this manual movement has calibrated the analog input from the potentiometer to the FMGS.

I will take a focus on it before doing the next flight and will say thanks for the useful hint.
Maybe I have to disable also the input processing of Skalarki in I/O profiler.

best regards, Frank

[EdwardInBeijing]

Assuming all the technical are working, I'm told by the pilots who fly my rig that it's good airman-ship to hold the nose down until VR. I usually hold the white double cross about halfway down.

I had a friend fly yesterday who forgot to do that and he belly flopped after the nose lifted at a bit before V1.

[digidax]

Problem fixed.

During flight the AP did switch off themself. To fix it, I have disabled the auto trim function of my motrized trim wheel. But then there was an error on the initial reading of the trim wheel position. So the aircraft gets an input of trimming nose up. The problem of the initial reading was fixed and with B47 also the problem of AP disengaging. The flight yesterday was done successful with motorized trim wheel and AP.

Yes, the A320 FCOM is also writing to pitch sidestick half way down until 80 kt to keep it more stable for winds during acceleration.
I do this everytime but with a wrong trim input - no way.

best regards Frank