Since I started reading this thread I've been thinking about this topic quite a bit, and these are my thoughts.
I think the concept of horizontal/vertical lift from the banked airfoil is pretty well understood and accepted by everyone here. So let's look at the forces involved in a left turn, for example.
The wing is banked left, therefore the wing generates a portion of its lift in a left direction. This wants to draw the wings horizontally to the left. The center of gravity of the aircraft is ahead of the center of pressure, so there is a tendency for the nose to want to turn
right. The effects of aileron drag and the greater induced drag of the higher wing also produce a
right-turning tendency. To counter this, we need a stabilizing force, not only to cancel the right-turning tendency but also to induce a left-turning force.
This is where the tail comes in. The tail in a conventional aircraft provides both yaw and pitch stability and control. Most here have correctly noted that the vertical stab/rudder will weathercock the aircraft into the turn because of the effect of the relative wind. You could also say that the rudder holds the tail still while the wing moves horizontally away from it. In a shallow turn, this is most likely the most significant component of the turning tendency. But it's not the only force involved.
There is more than one airfoil on an aircraft. Everyone forgets about the horizontal stab and elevator. In level flight, this surface balances the nose-down pitching tendency (caused by having the C of G forward of the Center of Pressure) by generating its own lift,
in the opposite direction of the lift generated by the wing. The elevator, of course, controls the wing's angle of attack by varying this downward lift component.
When you roll into a left turn, the horizontal stab's lift can also be split into horizontal and vertical lift components. And in a left turn,
the horizontal component of the h-stab's lift is to the right. Thus, you have the wing pulling itself left and the tail pulling itself right. And the aircraft (naturally) changes direction. Beyond about 45 degrees of bank, I suspect that this is the most significant turning force at work.
Going one step further, in order to maintain altitude in a turn you apply elevator to "hold the nose up." This has the effect of driving the wing to a higher AOA and increasing the vertical lift vector to balance the aircraft's weight. It also increases the wing's horizontal component of lift and thus its left-turning tendency. The elevator does this by increasing its own "negative" angle-of-attack and both it's vertical and horizontal lift vectors, thus increasing the tail's right-turning tendency. In a steep turn, the vertical stab's primary job is maintaining yaw stability. The "weathercocking" tendency of the tail is a function of the relative wind acting on the horizontal stab and that airfoil's own horizontal lift component.
Of course, all this talk of the physics of flight can easily mask the real issue - that the skills of flying are mostly about balance, feel and timing, and that developing a feel for the aircraft is more important than understanding the mechanics of it. I still think it's important though, and part of being a well-rounded pilot.
Stick and Rudder is excellent; I have it in my own library. Wolfgang understood what many fail to - that angle-of-attack and balance are the most fundamental aspects of flight. Everyone should read it.
I'm pretty sure Cat was being sarcastic.
Cheers, all.
Understanding begets harmony; in seeking the first you will find the last.
