On what basis are you asserting that P Factor produces a pitching moment? This is true in knife-edge flight or while skidding as I have written before, but it is generally thought of as a force that tends to cause left yaw in climbs and during slow flight with power, since those are more common flight conditions.

If P Factor is allowed to yaw the airplane left, as in a wings-level climb with insufficient right rudder (you use the rudder to keep the ball centered in climbs while flying your Cherokee), then precession will try to pitch the airplane up (or down while yawing right), but only while the airplane is yawing. This does not necessarily mean the nose will rise, as other forces may cancel the precessive reaction.

Are you saying that P Factor is the same as gyroscopic precession? If so, you are mistaken. P Factor is also known as assymetric propeller loading.

From the Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25), page 3-25:

ASYMMETRIC LOADING (P FACTOR)
When an airplane is flying with a high angle of attack, the “bite” of the downward moving blade is greater than the “bite” of the upward moving blade; thus moving the center of thrust to the right of the prop disc area—causing a yawing (emphasis added) moment toward the left around the vertical axis. That explanation is correct; however, to prove this phenomenon, it would be necessary to work wind vector problems on each blade, which gets quite involved when considering both the angle of attack of the airplane and the angle of attack of each blade.

Majortomski posted a part of the vector analysis mentioned above. Thanks again Tom.

Here's the FAA's web link so you can read the whole explanation in context with illustrations (your tax dollars at work):
http://www.faa.gov/library/manuals/a...83-25-1of4.pdf


P.S. MajorTomski might find it satisfying that elsewhere this section refers to the downward moving blade having a higher resultant velocity--it doesn't solely refer to "bite" or angle of attack.