Good book, by the way.

There has always been arguments over whether the pull to the left on a plane is torque, P-factor or a spiral prop blast. You can create experiments that show each to be the culprit so I would assume all of them have some effect.

On smaller RC planes you get very little P-factor or torque effect and, as has been mentioned, you can for the most part ignore it. As planes and props get larger, it begine to show up. Even the smaller giants, 80" spans with engines turning an 18 inch prop will exhibit a left pull on a pull up. The quicker the pull up, the more the left movement. It is definitely noticeable on squares. With the big planes, you learn to use the rudder and the throttle.