Re: Campbell's even crazier than a MANIAC? (archeopteryx climbing)

[Michael Habib <mhabib5@jhmi.edu>]

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.

Cheers,

--Mike


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