REFLECTOR: Aileron self-centering

[robajohnson at comcast.net]

>>The tendency for an airplane to return to wings level is dihedral effect.
The Velocity is supposed to be fairly good at trying to do this, although I
haven't really tested this on my 173 Elite RG.  You wouldn't think the Velo
would be as good as a C172, since the 172 is hanging under its wings - the
Velo has mid wings, and they go straight out.<<
You know Ronnie, I got a lecture on aerodynamics from Alan Shaw about 5 years ago explaining exactly that and now I am running a data retrieval program trying to pull *the details* from the old wet ware database and the search routine is failing! I still remember the big picture but I can't recall the exact details! :(
The big picture is that the winglets (tip sails, vertical stabs, what ever) are from an aerodynamic point of view really extensions of the main wing! So in effect your main wing tip is what, like 5 feet above the wing root but you have to average it out since MOST of the wing is flat so it makes for an averaged dihedral like 1/3 (or so) of the way up the winglet. That is why the Long EZ had anhedral, even with anhedral the plane still behaved like it had dihedral!  Without anhedral the dihedral "effect" of the winglets made it so stable it was hard to maneuver.
Now here is where it gets really fascinating and at the same time frustrating because I cant remember exactly WHY it was but as airspeed increases the center of lift moves and for some forgotton reason changes that averaged dihedral effect. So as your speed increases your positive stability decreases. That's why at lower airspeeds the Velocity's have positive stability (return to wings level hands off) but at higher airspeeds are stability neutral (roll into a small bank and it will stay in that bank)
Dm Rob
(Uh, I can't remember? Was DM an abbreviation for Dementia?)
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