Re: Sort Your Story Out! (Was: 2 refs that were once new...)

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "James R. Cunningham" <jrccea@bellsouth.net>
To: <david.marjanovic@gmx.at>
Sent: Friday, September 21, 2001 12:53 AM

> David Marjanovic wrote:
>
> [...]
>
> > The measured feathers (at 25 % away from the tips) are the first and
fourth
> > primaries which are quite oblique. So one should expect them to have an
> > "aerodynamic shape" for lift, or am I oversimplifying again? :-)
>
> You may be.  The "aerodynamic shape" has nothing much to do with lift --
it has
> more to do with the angle of attack at zero lift.  Camber doesn't have a
great
> deal of effect on the lift slope.

Oh, yeah, forgot that. Isn't it probable that camber becomes important above
a certain size/weight, regarding flat insect wings?

> Have you thought about looking at the
> chordwise pressure distribution vs. the nose-down pitching moment of the
feather
> with respect to the effect of the asymmetry on torque in the shaft?

No, and Speakman & Thomson haven't either. When I try to imagine :-] that,
anyway, I think a downstroke with symmetrical wing feathers would tend to
blow the leading vanes upwards, creating lots of slits in the wing, if the
feathers aren't _very_ stiff (or very narrow, which they are not in
*Archaeopteryx*). Of course this cries for real experiments...

The observation that no living flying bird has (sub)symmetrical wing
feathers seems to hold, however.