Rudder
I just have to say that learning to fly on a 3 Channel makes you
more aware of the Rudder and what it does. Being that is your
main contoll of the plane beside elevator. I was taught from a
old timer on a Kadet Sr. 3 Channel and flew it for a year. A lot
of my buddies in the club told me why bother on a 3 chanell but
I did it anyway. Its made me very aware now of the differance
between aileron and rudder. We had 4 training pilots in our club
crash their planes in the past due to misunderstading of ailerons
and rudder. Tip stalls on final Crosswind take offs ETC. My point
is it helped me. 6planes later Flying smooth and understanding
how I was trained ....... Happy Flying