I can't keep control of the plane on the runway :( XP12

[picnic]

So I've got the Archer III TX/LX package. Using XP12, when I get up to 45-50 knots, the plane becomes uncontrollable for me. The aircraft will veer violently left or right and is uncatchable. Before reaching these sorts of speeds the plane is controllable using the rudder. If I use the XP11 ACF file it's fine but the XP12 one I find impossible.

Am I the only one?

Things I've tried.
I've changed sensitives and tried changing response curves. Makes no appreciable difference.

I've tried disabling my Yaw axis so XP12 does the rudder control for me. That's worse as there appears to be no attempt of XP making any rudder control.

I've swapped out my Alpha Yoke / CH Products rudder pedals for an old Sidewinder joystick, still uncontrollable.

I tried it on my laptop with the same result.

Another strangeness is this, if you fly with the XP11 ACF you get prompted to auto switch to the XP12 version. There is also a folder with the XP12 ACF file and instructions on how to manually install it. These 2 XP12 ACF files are different! If anything the manually installed one is factionally more forgiving but still goes barmy for me on the take off roll.

Any help gratefully received, thanks

[srcno]

I have been experiencing the same issue. I recently followed the videos recently posted to XPlaneOfficial's YouTube channel about troubleshooting issues like this. I ruled out the rudder pedals (input and flight control position values are consistent with my inputs) and convinced there is something wrong in the airfoil design of the Archer.

You should be able to confirm similar by a) in flight configuration -> data output, search rudder and set "joystick aileron/elevator/rudder" and "flight controls aileron/elevator/rudder" to display in cockpit, b) start a new flight, c) Shift-8 to set the chase view, d) press Ctrl-m a few times until you see Elemental forces, and d) begin a regular takeoff. I also set video recording to a high quality and recorded to review at low speed.

You'll see the position of the nose wheel properly aligns with the desired position on the rudder pedals. However, you'll see lateral forces on wheel do not match the input and expectation. However, you will also see significant lateral forces on the body of the airplane. While some of these forces make sense due to the airflow off the propeller, they seem fluctuate considerably and exceed the expected forces.