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Old 29th Dec 2004, 16:30
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bookworm
 
Join Date: Aug 2000
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I'd strongly recommend a look the aerofoils chapter in John Denker's See How it Flies.

In particular, when you start using words like "deflection", it's worth a look at his section 3.6_Air Is A Fluid, Not A Bunch of Bullets. I'm not suggesting that deflection is incorrect, just that it can put inappropriate physical models into your mind.

From a terminology point of view on downwash, it's worth remembering that the air bends around the aerofoil and essentially returns to its original direction over a distance of the order of a few chord lengths. The rather more persistent downwash between the wingtips is (arguably) a result of combined effect of the wingtip vortices of a finite wing and is balanced by an upwash outboard of the wingtips. For that reason, some authors tend to use the word downwash only in the context of finite wing effects (for example to calculate induced drag).
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