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Re: [dinosaur] Archaeopteryx had active flapping flight ability based on wing bone geometry (free pdf)




On Mar 15, 2018, at 5:24 AM, Ruben Safir <ruben@mrbrklyn.com> wrote:

On 03/14/2018 11:37 PM, Mike Habib wrote:
Anatomically, hind limb proportions and position predict launch mode in birds, not sternal morphology or forelimb morphology.

I don't accept that it is an either/or proposition. 

Regardless of whether you accept it, the reality is that launch is mostly hind limb powered in birds and hind limb characters are what predict running vs leaping takeoff. This is not an idle speculation on my part or a hypothesis. It is a measured result obtained from hundreds of hours of theory work by folks like myself and more hundreds of hours of hard experimental work by folks like Kathleen Earls. 

And since, as you
say, we have little data on the wing lift comparisons, I believe it even
less.  

What I said is that we have few experimental data on vortex generation during running launch in aquatic birds. We have quite a bit of data from other launch and flight conditions. Animal flight is not some vast, speculative unknown.

One thing that is certain, without the wings, it can leap all day and land on its face.

Leaping animals that lack wings donât land on their faces (usually), they land on their feet... itâs called jumping.

The most common time they use there breast muscles are on launch and it
is unfathomable that they could launch terrestrially from the ground
without the modern wing stroke.  

You can find it as unfathomable as youâd like, but physical modeling says otherwise: see Dececchi et al. (2016). Seriously, we have cited this paper like eight times now in this one thread...

Cheers,

âMike Habib