It depends on A/C aerodynamics wheter the plane starts to turn w/ bank angle != 0 or not. Usually the plane does not, so FCPC is mixing some rudder to make the plane turn. Which force would else make the plane turn? And I'm sure Bank Angle does not, may help a little bit.
In fact, for a conventional aircraft with wings, a horizontal stabilizer, and a vertical stabilizer, the bank angle *is* the main thing that makes a plane turn; or, more specifically, the potential sideslip from the bank angle makes the plane turn, since it will weathervane to keep flying directly into the relative wind.
The rudder is entirely a secondary control in a turn: it exists mainly to compensate for aerodynamic design flaws (or design compromises, to be more kind). Ideally, you shouldn't need it at all in a turn, but most planes have some peculiarities that make them draggy on one side or another during a turn -- people have already mentioned adverse aileron drag (which exists only when the ailerons are deflected), but other kinds of drag can exist as well. In fact, in some turns, you actually have use *outside* rudder (i.e. opposite the turn direction) to keep the plane from skidding -- that pretty-much demolishes the idea that the rudder makes the plane turn.
For a normal trainer or general-purpose single, like a Cessna 172 or 182, a PA-28 or what-have-you, you can fly all of your normal turns without using any rudder at all. We simulate this fairly accurately with the 172 in FlightGear, if you want to give it a try (turn without using any rudder, and watch how the ball stays mostly centred anyway).
All the best,
David
_______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
