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Old 30th Mar 2006, 10:20
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Islander2
 
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Originally Posted by IO540
Islander - I maintain that all this is derived from Newtonian mechanics.


I have two problems with that:
a) Saying that lift is governed by Newtonian mechanics, and that's that, is about as helpful in understanding the subject as .............!!
b) Lift as a Newtonian reaction requires the airfoil to deflect the streamlines downwards. Unfortunately, without circulation - which requires viscosity - the streamlines aren't deflected downwards! Look in any text at a representation of inviscid flow around an aerofoil and tell me how you get a Newtonian reaction from that. So a knowledge of Newtonian mechanics alone ain't sufficient.




Genghis said:
"Just butting in, Flyandteach was asking about pilot's perception, not about what actually happens."
True enough, and I can see where you're coming from! But shouldn't the educational objective be to achieve some convergence of the two?

Edited to add one last observation before getting my hat and coat, never to be seen on this thread again! From Chris Carpenter's book referenced earlier:

"Interestingly, therefore, Newton's momentum theory of lift, although useless for the aerodynamics of conventional flight, actually comes into its own in modern hypersonic flight analysis." (my italics)

Last edited by Islander2; 30th Mar 2006 at 10:47.
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