Bill,
Yes, I know that the gyroscopic forces and thereby follows gyroscopic precession are very large in aerobatic planes, but that's due to the changing attitude of the prop disc, right. On a plane either on the tarmac or in a steep climb, the attitude of the prop disc is more or less constant. I want to be sure I am right here. When we talk P-Factor we're just talking the effect the angle of relative air to the prop disc has on the plane, not the whole yawing thing, i.e. the swirling air and other possible factors. If the P-Factor is limited to just this, then I think the force of this is very minimal, and the yaw is really caused by the air stream.

DKjens