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Re: pteros have lift-off
As I have said over and over again, launch is at about 25 to 35
degrees. 25 degrees is lower than 30 degrees. 35 degrees is
higher. The animals can adjust the launch angle at will, though
larger animals do tend to go out at a lower angle. I suggest that
birds of any species are not necessarily a particularly close
analogy for terrestrial pterosaur launch since they do it so
So at a launch angle of 25-35º ground effect is employed for a very
short duration in pterosaurs? As opposed to airplanes and big birds,
which stay within a downbeat of the ground or water until sufficient
speed is attained...
Looks like: 1) crouch simultaneous with wing unfolding and upbeat.
2) hindlimb extension simultaneous with first downbeat. No
surprises. Probably common to most birds.
And mostly irrelevant to pterosaurs.
Maybe not. That's what we're trying to understand here. Pterosaurs
came from a lineage of hind limb leapers.
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.
Of who's ? Birds generate as much as roughly 90% of their launch
power with the hindlimbs, depending upon species.
Mike Habib. As a courtesy, Jim, you were cc'd. Since pterosaurs came
from a lineage of hind limb leapers, there was a time when
pterosaurs, or their immediate ancestors, ALSO generated as much as
roughly 90% of their launch power with the hindlimbs. If that
gradually decreased as evolution changed things, a change in launch
mode, such as you suggest, has to be documentable.
What if someone found trackway evidence for a bipedal pterosaur or
two? Would that change your view?
And this is incompatible with small and large pterosaurs because...?
It's not at all incompatible with pterosaurs -- it just has nothing
much to do with them.
I think the jury is still out. You present a good case, but it
depends on quadrupedality in all pterosaurs, something that has not
yet been documented. This is pertinent because they came from bipedal
Final question: how much angle do you figure at the carpus to create
your Z fold in the forelimb?