Re: large fossil birds

[don ohmes <d_ohmes@yahoo.com>]

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!

Don

--- Patrick Norton <ptnorton@suscom-maine.net> wrote:

> From: "Tim Williams" <twilliams_alpha@hotmail.com>
> 
> > 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.
> 
> PTN 
> 
> 
>