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RE: NEW PAPERS and flight stroke
Jim Cunningham wrote:
> What I'm trying to ask, is what is the physical mechanism that causes
> this to be the case? How are the forces produced? Note that I'm not
> arguing that this isn't the case.
I could be misreading your question, but my take on it is this: if you want
to impart a force against a fluid, it's better to execute a widest
practicable arc of excursion. You mentioned the motion of an oar during
rowing. I'm aware that this motion is NOT analogous to the motion of a wing
during flapping flight. However, the blade is positioned at the end of the
oar, and this part 'pushes' against the water - far more effectively than a
simple pole (depending upon the blade's orientation). The long pole
provides the actual movement responsible for steering.
> > This is demonstrated by 'flying' frogs with their webbed digits;
> > they move their hands and feet to help steer them during their fall.
> What is the approximate aoa that they use when doing this?
The authors do a better job than I could to explain:
Emerson, S.B. and Koehl, M.A.R. (1990. The interaction of behavior and
morphological change in the evolution of a novel locomotor type - flying
frogs. Evolution. 44 (8): 1931-1946.
McCay, M.G. (2001) Aerodynamic stability and maneuverability of the gliding
frog _Polypedates dennysi_. Journal of Experimental Biology 204 (16):
> > For a flapping flyer (birds) the outer wing is primarily responsible
> > for generating thrust during flight.
> Yes, and lift and drag too.
I was under the impression that the *entire* wing (and the inner portion
especially) were responsible for lift-generation. The majority of thrust is
provided by the outer wing - but I wouldn't have said the same for lift.