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Re: Hone and Benton 2007 (their second paper)



Michael Habib wrote:

Being in a tree actually makes launching quite easy, since the animal can use a gravity-assisted >launch. Essentially, an arboreal pterosaur could simply drop off the tree and then start flapping. It would hit flight speed quite rapidly using gravity-assisted launch, so the animal need not fall very far.

If I was a pterosaur, and I was dropping out of the tree as a means of achieving flight speed - would I open my wings during this 'drop', or would I keep them closed? I was thinking that by keeping the wings folded, I would achieve flight speed sooner, since open wings would only create drag during the brief descent. But if my wings are already open during the 'drop', then they are already positioned for the downstroke.


Arboreal birds use gravity assisted launches, as do cliff-dwellers like tropicbirds. Arboreal birds do not require gravity assistance, while tropicbirds (and frigatebirds) often do.

Can you expand on this a bit?

However, in both cases, the vertical descent prior to reaching cruising speed is quite short. You can see it if you look for it, however. Like arboreal birds, a tree-dwelling pterosaur would not require a gravity assisted launch, but it saves energy if you happen to be at a high point already.

So in this situation too, would pterosaur wings be open or closed during the vertical descent, prior to reaching cruising speed?


I hope that helps; definitely an excellent question.

It does; thanks for an excellent answer.

Cheers

Tim

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