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Re: Cost in Aquatic Birds (the big one)
Williams, Tim wrote:
> I'm going to reveal my ignorance here and ask if you might define
> 'pronation' and 'supination' in the context of avian flight.
This is a very loose description for purposes of approximate visualization
only. Pronation is usually taken as a nose-down rotation of the extended wing
about its long axis measured relative to the horizontal plane or the body of
the animal. Note that when flapping, the pronation (nose-down rotation relative
to the horizontal plane) during the downstroke is often (usually) a suppination
relative to the vector of the inflowing air, with the amount of the airflow
suppination vector increasing spanwise because of the increased downward
tipspeed. Suppination is usually taken as a nose-up rotation of the extended
wing about its long axis measured relative to the horizontal plane or the body
of the animal. Note that when flapping, the suppination (nose up rotation
relative to the horizontal plane) during the upstroke is often(usually) a
pronation relative to the vector of the inflowing air with the amount of the
pronation increasing spanwise because of the increased upward tipspeed. The
spanwise crossover point between the pronation and suppination relative to the
incoming air vector depends upon airspeed, body bobbing, and flapping
kinematics, but I've not seen this discussed in the field of animal flight (I'm
sure it has been -- I just don't remember having seen it). It's well known
among folks who are interested in ornithopter kinematics. This has a lot to do
with why the average stroke plane vector is usually angled down and forward,
and why it is angled more forward at low airspeeds.
> Ah yes, Mr Tom 'Gun-Control-is-holding-it-with-both-hands' Clancy. I never
> much cared for Heinlein, but I find Clancy readable.
I admit to being predjudiced. Robert's widow is a dear friend of my wife's and
mine, and I'm a director on the board of the Heinlein Foundation that they
established to support the library in Butler, Missouri (Robert's home town).
Hazel Stone is an undisguised clone (so to speak) of Robert's wife Virginia and
shows up in more of his books than any other character. For those who are
interested, she is also the source for the Poul Anderson character 'Virginia
Greylock' (Virginia Matuchek). Clancy quotes Robert from time to time in his
> > Now that Clancy has sort of shifted the John Ryan books into an
> > alternate universe, I keep expecting Hazel Stone to show up in a
> > cameo.
> Perhaps she can help Jack Ryan against those Ebola-wielding Iraqis, should
> they ever return.
They likely will.