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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. PhD. Candidate Center for Functional Anatomy and Evolution Johns Hopkins School of Medicine 1830 E. Monument Street Baltimore, MD 21205 (443) 280 0181 habib@jhmi.edu