Re: pteros have lift-off

[David Peters <davidpeters@att.net>]

I understand about a running start and compliant surfaces. So, let's  
throw the running start out of the equation.

I see storks and herons taking off from a standing start, perhaps  
using ground effect before gaining cruise speed. There's no 30º  
trajectory there.

Do your figures take into effect 'ground effect' flying?

I mapped sequential photos of a pelican taking off (I can send this  
via a non DML email). Although the pelican is airborne immediately,  
the acceleration over a half dozen frames is easy to measure while  
flying in ground effect. Maybe, like pelicans and herons the  
availability of ground effect means pterosaurs don't have to reach  
cruise speed within a second after take-off? Perhaps a trajectory in  
big pteros lower than 30º would be equivalent (i. e. ultimately  
leading to flying at cruise speed)?


http://www.youtube.com/watch?ie=UTF-8&safe=off&q=stork+take-off&v=rKt- 
AXgQo-E&sa=N&eurl=http%3A%2F%2Fvideo.google.com%2Fvideosearch%3Fum% 
3D1&ndsp=18

The above is a YouTube of a heron take-off from a standing start.  
Yes, it happens very fast.

Looks like: 1) crouch simultaneous with wing unfolding and upbeat. 2)  
hindlimb extension simultaneous with first downbeat. No surprises.  
Probably common to most birds.

So, I'm gathering from the video that a large amount of thrust is  
generated by the wings along with thrust from the hind limbs. Which  
seemingly relieves the hindlimbs of a large amount of duty -- which  
was a major concern of yours.

And this is incompatible with small and large pterosaurs because...?


Best, and thanks for your patience.

David