Re: Pterorhynchus dewlap

[jrc <jrccea@bellsouth.net>]

----- Original Message ----- 
From: "MICHAEL HABIB" <habib@jhmi.edu>
To: <dinosaur@usc.edu>
Sent: Thursday, February 02, 2006 3:42 PM
Subject: Re: Pterorhynchus dewlap


> In fact, with their high-aspect ratio wings and excellent lift 
> coefficients, many of them probably flew very quickly > (being large helps 
> in that arena as well).

It does.  The big azhdarchids had wingloading as high as equivalently sized 
sailplanes and flew at about the same speeds.  If you want to get a handle 
on Qn, Arambourgiana, or Hatzegopteryx performance, take a look at the 
Carbon Dragon, the WindRose, or the SparrowHawk.  Vne is different, but much 
of the other stuff is close enough for government work.  These suckers were 
fast.  They had to be to be to support their weight.  Keep in mind though 
that pterosaurs have a distinct upper speed limit as the CL decreases and 
the aeroelastic number declines with speed.  Go too fast and the wings 
flutter.

> Granted, they might have had less drag and moved more efficiently without 
> the crests, but (as I mentioned in my last post, and as Jim also alluded 
> to) the L:D ratio was probably good enough to get by.

Yeah.  I wouldn't expect it to be any better than need be.  They had good 
wings, so could afford crappy excrescences like big heads, long necks, and 
other such stuff.

> I would flip the point of view a bit and say that pterosaurs were so 
> efficient that they could afford big nifty crests, > rather than saying 
> the presence of large crests implies low performance.

I agree.  The presence of large crests, big heads, and long necks implies 
very good performance otherwise.  I think even an albatross would have 
trouble performing if you stuck an azharchid head and neck on him.  In 
passing, some pterosaurs had higher aspect ratios than albatrosses do.

Jim