Having trouble with Physics & Rotation / Angular Velocity..?

I’m having an issue where my vectors just do not seem to rotate as I think they should. I’ve tried rotating the vector by Quarternions and that doesn’t seem to help, and even altering the vector based on the directional vectors of the component (and the Quaternion too). Yet for some reason, when adding Pitch Rotation, I get a substantial amount of Yaw rotation too, which builds up into a huge value. What’s odd is that the length/sum of the output vector when it’s adding Z-rotation is way higher than what I’m giving it for input in some extreme cases.

I can’t figure it out, the Z axis just seems to go into overdrive. PithcAccel is the pitch acceleration applied to the craft, which has to be in World-Space since ‘SetPhysicsAngularVelocity’ works in World Space, not Local Space. AngularAccel is added to the existing World-Space velocity each frame.

I’ve tried rotating the Vector based on a Quaternion Rotation:



PitchAccel = FVector(0.f, **PitchValue**, 0.f);
AngularAccel += QuaternionRotation.RotateVector(PitchAccel);

UpdatedComponent->SetPhysicsAngularVelocity(AngularAccel * DeltaSeconds);


I have also tried the more desired approach, which is rotating based on an axis (the result in the video):



FVector PitchAccel = UpdatedComponent->GetRightVector() * **PitchValue**;;


And Finally, rotating the Pitch Acceleration using the Transform of the vehicle:



FVector PitchAccel = UpdatedComponent->GetComponentToWorld().TransformVector(FVector(0.f, **PitchValue**, 0.f));


This is the result. Am I just doing something fundamentally wrong here? I just end up spinning on Z when manipulating the pitch value, which just makes no sense at all. Notice the debug strings on the top left. Obviously, I will get a tiny bit of Z-rotation at glancing angles on the terrain (which my craft self-rights too), but it shouldn’t be anything like this amount… The same thing happens with other rotations that I try and do on local Axes, like adding small amounts of Roll when strafing or turning.

Note: I’m not adding ANY Steering in this video, it’s been disconnected.