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Re: FYI -- Microraptor gui, Burnham and Alexander, PNAS...
Tim Williams wrote:
Dan Chure <email@example.com> wrote:
Alexander, D.E., Gong, E., Martin, L.D., Burnham, D.A., and Falk,
A.R. (2010). Model tests of gliding with different hindwing
configurations in the four-winged dromaeosaurid _Microraptor gui_.
PNAS published online before print January 25, 2010, doi:10.1073/
... Although the hip joint requires the hindwing to have at least
20° of negative dihedral (anhedral), all configurations were quite
stable gliders. ...
Gee, that's nice - but I note that not a single flying animal alive
today, even unpowered ones, is particularly passively stable (most
derived, powered flyers are extremely unstable, actually). Granted,
some of the gliders are more stable than most powered flyers, but they
still have motor control, meaning that being stable enough to fly
effectively as a rigid structure is not of great importance. Unless
Microraptor corpses were gliding after undergoing some serious rigor
mortis... Seriously, though, if we use the criterion that the more
stable planform is best, then many living gliders would be ruled "poor
fits". As a result, the "build a static model and throw it" test
would seem to fall on the weak side with regards to proof of concept.
I'm not saying that it is not cool and fun, but it may not give the
desired information, *unless* one is trying to incorporate aspects of
biological planforms into a passively stable artificial glider model
for engineering purposes.