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Re: Campbell's even crazier than a MANIAC? (archeopteryx climbing)
Augusto Haro wrote:
But I sometimes read that the trends towards gliding are opposite to
these towards flapping flight; can somebody tell me why? Most flyers
seem to be good when gliding (although small bats and birds generally
glide less). Among the basalmost living birds, I have been told by
biologists that tinamous commonly glide after a phase of flapping
during their short-range flights. Many other birds glide
intermittently with flapping.
Many powered flyers are indeed good gliders. The issue at hand
involves what happens to circulation and lift production for obligate
gliders (especially those with low aspect ratios and elastic patagia)
when they flap their airfoils. It turns out that for many glider
morphologies, oscillation of the airfoils actually reduces performance,
especially if flapping is weak. The adaptations that promote powered
flight are therefore somewhat at odds with gliding performance, in that
particular type of situation.
Michael Habib, M.S.
Center for Functional Anatomy and Evolution
Johns Hopkins School of Medicine
1830 E. Monument Street
Baltimore, MD 21205
(443) 280 0181