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Old Dec 05, 2012, 08:52 AM
xlcrlee is offline
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Originally Posted by flyzguy View Post
.... For thermal soaring, I do know of a trick to make a glider "auto soar" by carefully tailoring wing twist along the span. Basically you design the wing to stall asymmetrically and then trim it to fly a very stable glide near stall. When such a plane encounters a vertical gust which increases AOA on the plane, it will always stall one wing first, creating a nice turning action that causes it to naturally turn around updrafts. This has been successfully designed, built and flown. But this requires careful tailoring of both airfoil section and spanwise lift distributions at low reynolds numbers, along with a very good understanding of the dynamics (have to have stable spiral mode) of free flight models.
OK, you are "starting to get it". The birds' [and "my"] system does in fact involve using the effect of a changing onflow-vector, but since it involves the tip-vortices specifically, it applies to BOTH wings differentially, in a way that does not need to stall either wing to get an automatic course-change action [not a circle!!].

I didn't invent anything new: so far as I can tell it was used even by reptile Pterosaurs millions of years before birds evolved from a different line [warm-blooded, feathered (to keep eggs & parents warm), hollow-boned, meat-eating dinosaurs .... like T-Rex (the animal, not the helicopter) and Velociraptor].

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Last edited by xlcrlee; Dec 06, 2012 at 04:37 PM.
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