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Re: large fossil birds
IMO-- As individual feathers are enlarged, the ratio
of _weight/airfoil area_ necessarily increases. This
limits the size at which a feather can be
aerodynamically efficient, which in turn limits the
total airfoil size achievable w/ the feathered wing.
If you want to build a roof that is as light as
possible, ya don't use shingles!
--- Patrick Norton <email@example.com> wrote:
> From: "Tim Williams" <firstname.lastname@example.org>
> > I wonder why...? Why couldn't birds get as large
> as the azhdarchids?
> My personal theory about this is that maximum
> wingspan in birds was
> constrained by the fusion of the carpometacarpus,
> which required the
> elongation of primary flight feathers for the
> development of thrust.
> Pterosaurs had no such hereditary mechanical
> constraint and were able to
> extend wingspan by elongating the fourth finger.
> This was probably a
> stronger mechanical arrangement for the outer part
> of the wing than what
> evolved in birds, which at extreme sizes allowed for
> longer wings that could
> develop more thrust to support more massive bodies.