Re: "deep wing" Karlsruhe azhdarchide, etc.

["James R. Cunningham" <jrccea@bellsouth.net>]

David Peters wrote:
> 
> Is so, Dr Unwin has made his point. The pterosaur cloud is smaller.

I think Dave U is right, in that it is smaller.

> Jim Cunningham may wish to weigh in on this subject since the hind limbs
> may have acted as elevators in pterosaurs,

Keeping in mind that I prefer the narrow-wing model for most pterosaurs,
and my response presupposes that preference, wing sweep seems to have
been primary for pitch, and the hindlimbs were not primary as elevators
(though they could serve that function -- with some limitations).  There
is a limited 'dead band' for hind limb lift forces that they can't
maintain because of flutter associated with aeroelastic number. 
Asymmetric positioning of the hindlimbs is more important for correcting
major yaw upsets (not required for minor yaw corrections), and the yaw
function is far more critical to flight than a hindlimb elevator
function.  The hindlimbs were also used to help control glide ratio
during descent, drag during the landing process, and for lift and drag
control during launch.

> which brings up the
> possibility that aerodynamic efficiencies may have restricted
> dimensions, rather than dermal connections.  Birds tuck in, both in the
> air and on the ground, so comparisons may have little functional
> cross-correlation.

In general, birds are doing something quite different with the
hindlimbs.  I wouldn't expect a lot of cross-correlation.