Originally Posted by
Cbusbased
Torque is about the roll axis (roll) while P-factor is about the vertical axis (yaw). Thus, if you correct for the left-turning tendency (p factor) you must also correct with aileron correction in order to maintain coordinated flight.
Exactly, and of course on the ground the landing gear prevents the "roll", but more pressure is applied to the left gear due to the force still being there, "dragging" the airplane left.
I think this "force" is only an issue when accelerating the prop. At a steady state, the engine mounts and stabilizer surfaces are configured to eliminate any residual "torque" effect caused by friction/drag in the engine and moving parts, but you do get a little when you change power settings, "accelerating" or "decelerating" the prop. When you try to spin the prop faster, airplane wants to go opposite direction, but of course it's a LOT heavier than the prop, so the effect is still pretty minimal, not to mention there's probably some additional resistance caused by the static pressure around the aircraft.
Of course, this all gets confusing because the FAA calls P-factor, torque, slipstream and gyroscopic effects all "torque effects", which they are because they are all forces x distances for the most part, but the specific effect of "torque" when referring to the opposite effect of accelerating the propeller would of course be a roll about the longitudinal axis. "Torque effects" is kind of a poor name, but "left turning tendencies" isn't much better, as many of these forces are completely opposite of that in certain conditions.
Again, I can't say I've noticed when aileron is necessary in any flight not involving accelerating or decelerating the prop, and even then just a slight effect. It seems far more prevalent to find people offsetting P-factor with aileron, flying uncoordinated and keeping the airplane in enough right bank to offset the yaw to the left.
Thoughts anyone?