Re: poling dangers

[Michael Habib <mhabib5@jhmi.edu>]

> > > >  I think you are having issues with the sticky problem of aquaeous
> drag. If I'm reading your right, in your vision of the situation, I
> sense a need to elevate the wings quickly, which would be difficult
> under deep water during poling...

That is part of the problem, yes, but there is also the problem of the 
forelimbs being unable to push against a substrate to produce launch 
forces (see below).

> 1) As the head rises above the surface, the eyes, set far back on the
> skull, break water, sense danger then things start moving. First,
> everything flexes in panic. Flexion of the humerus brings the already
> folded wing forward to the surface in a configuration the pterosaur
> might also use to rest on  dry ground...Momentarily freed from the 
> water, the wings snap laterally and start flapping, but only employing 
> the top half of
> the beat cycle in order to avoid reentering the water.

I am impressed that you worked that out off-the-cuff so well, but I am 
somewhat unconvinced that Quetzalcoatlus could launch in that manner.  
Jim already responded to the scenario better than I could, so I'll just 
add that simply freeing the limbs from the water is probably 
insufficient.  In that scenario, the Quetz. has to start flapping 
frantically to get up to speed.  Not only are the wings going to hit 
the water during the first stroke cycle, but I would also expect that 
the launch would be very slow indeed (and it brings up the question of 
whether Quetz. could launch without pushing off the ground at all).  A 
Quetz. launch would be darn fast if it could catapault from a 
substrate, but probably pathetically slow if try to "hovercraft" its 
way into the air.


Cheers,

--Mike Habib