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Old 12th Nov 2017, 20:30
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172510
 
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The lift formula is in fact a definition. It's the definition of the coefficient of lift. There is no knowledge implied in a definition. You may define whatever your want.
The knowledge comes when you make experiments in a wind tunnel. Then you can see that the coefficient of lift, at usual GA aviation speed & pressure, does not depend on speed, nor on temperature, nor on pressure. The coefficient of lift only depends on the angle of attack and on the shape & surface of the airfoil. That's an experimental knowledge, and it's enough to built safe aircrafts.

Most of the time in history, knowledge comes first with experience, then a mathematical model is built and some theoretical knowledge can be built on the basis of the previous experience.
Most explanations of lift in pilot's manual don't explain anything (see https://www.grc.nasa.gov/www/k-12/airplane/wrong1.html, https://www.grc.nasa.gov/www/k-12/airplane/wrong2.html, etc.).

The best explanation, to my point of view, is to explain the actual experimental protocol that led to the properties of the coefficient of lift.
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