djlyon,
I have never been able to get an explanation why it is, that on one page of the private pilots manual etc., "gyroscopic precession" is mentioned as a factor, but then when it comes to the P-factor, that is all forgotten. If "GP" is taken into account, the force created by the higher angle of attack on the downward moving prop blade should not take effect until 90 degrees later, causing a pitch up effect, not a yaw effect. I was just recommended not to engage in a this discussion with the examiner he he.
I do hoowever agree that right thrust is necessary, on 3D planes more than any others. It is obvious on an upline and when hovering. For a speed plane, no side thrust may be beneficial.
DKjens