On Mon, 18 Mar 2002 14:41:55 -0800 Andy Ross <[EMAIL PROTECTED]> wrote: > >What you're seeing is the fact that, when you add flaps, you increase >the nose-down pitching moment of the wing. This happens, >qualitatively, because most of the lift you add gets >added at the back of the wing where the flap is. Most of the "regular" >lift happens toward the front of the wing, where the point of lowest >pressure on the upper surface is.
Yep. You can also imagine the flap as a little wing unto itself, with a lift distribution over it. The total lift due to the pressure distribution over it gives a resultant that acts on the aircraft as a whole in a way that is dependent on where it lies relative to the CG. I, too, have heard real pilots lament over the way this is handled in most commercial flight simulators. >The question is: is the drag added due to flap deflection >more or less than the drag reduction due to lower AoA? I don't know. > It's probably aircraft-dependent, and I haven't seen any >numbers anywhere that talk about it in the context of a whole aircraft. Off the top of my head, given without much thought: There's the profile drag due to the deflected flaps, and also the induced drag due to increased lift. Are you modeling that? Or, is that inherently included in the way YASim does its forces and moments? This is definitely an aircraft dependent thing, from what I have heard (and intuitively) for many reasons, but including one you haven't mentioned: on a high wing aircraft when flaps are deployed there are effects on the horizontal tail, too - the downwash is increased for one. Jon _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
