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Old Mar 11, 2012, 09:52 PM
aeronaut999 is offline
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The Willamette Valley, Oregon
Joined Dec 2008
1,302 Posts
(Edit May 2012-- my thoughts on this matter have now changed significantly-- I'm still convinced that the earth "feels" a downward push from the wing of an aircraft in flight, equal in magnitude to the weight of the aircraft, which is also equal to the upward gravitational attraction that the aircraft exerts on the earth, but I no longer believe that this downward force need involve any specific amount of downward momentum of the air (downwash). For more, see posts 58, 61, and 72. End edit.)

Ladies and gentlemen this is a sincere thread. Motivated by the philosophy that we can approach the truth by many different converging roads-- i.e. it is entirely valid to seek non-aerodynamic evidence for the relationship between downwash and lift. That's the way the world (cosmos) is put together.

As far as the aerodynamics side of the argument goes, I remain interested in getting better insight as to the questions posed in posts # 29 and # 31.

The answer appears to lie in the role of the tip vortices? Not sure this is it though-- tip vortices may relate to the (drag) cost of producing downwash rather than the (volume* velocity) of the downwash field-- even with end plates (no tip vortices), in a wind tunnel, surely increasing the wing chord has some effect on the flow behind the wing? Scaling up the chord must also scale up the "picture" of what is happening behind the wing in some way, so that the (volume* velocity) of the downwash field is increased, even if the downwash angle as measured at some particular scale-independent point is unchanged? No?

Thanks very much.

Steve
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Last edited by aeronaut999; May 10, 2012 at 05:43 PM.
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