Andy Ross writes: > The real reason for washout (or at least a better physical > explanation) is this: the washout that maintains the tips below > stall AoA keeps as much of the "stable" derivative as possible out > on the wing tips where the moment arm is long. If the early stall > happens near the fuselage on a short moment arm, then the overall > behavior will still be stable, not divergent, even past the peak of > the "whole aircraft" lift curve.
I found it easier simply to picture different 2D sections of the wing stalling at different times, but I can see how your explanation might lead to a programmatic solution faster. > Cool. I learned something this weekend. A "snap roll" is a > physically well-defined thing: it is a roll executed in a > post-stall environment where the roll-moment-due-to-roll-rate > coefficient is divergent. Isn't the snap roll usually uncoordinated? I've never done aerobatics myself. If it is, then I wonder what the role of the uncoordination is. > So anyway, YASim needs to model washout. In principle, this should be > pretty easy. Each wing segment (Surface object, as currently > implemented) gets its own orientation already. We just need to decide > on a way to specify it to the solver. Would a linear interpolation > between "base" and "tip" incidences work? I don't know much about > washout design as implemented on typical aircraft. A fancier > mechanism would allow you to specify washout as an interpolated curve > per-station curve along the span, but that sounds like it might be > overkill to me. Does anyone have a preference? Start linear -- the real-world is probably not predictable enough that anyone would notice increased realism from an interpolated curve. On a separate note, I make no claim to understand how flaps and washout interact, but perhaps that's more obvious to others. All the best, David -- David Megginson, [EMAIL PROTECTED], http://www.megginson.com/ _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
