Thread: Theory on lift
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Old 30th Jul 2018, 03:04
  #371 (permalink)  
A Squared
 
Join Date: Feb 2000
Location: Alaska, PNG, etc.
Age: 56
Posts: 1,526
Originally Posted by VinRouge View Post


Ok John! (you asked for it)

How does the traditional theory of lift as taught on most groundschools and even at GCSE, explaiin how a paper aeroplane flies? Or a symmetric foil section?


The tired old "symmetrical airfoil" argument is only appealing to those who believe that the stagnation point (point where airflow divides between under the wing and over the wing) on a symmetrical airfoil operating at a non-zero angle of attack is located on the airfoil's axis of symmetry. It's not. There are numerous wind tunnel photographs of symmetrical airfoils with smoke generator streamlines switch demonstrate the fallacy of this.

Originally Posted by VinRouge View Post
Ive also done the bernoulli sums on a standard NACA section and considering 2D flow only, increased velocity due to "further to go"...it explains at maximum about 5% of the lift actually generated in accordance with the standard lift equation and experimental Cl figures.
*sigh* the "equal transit time" strawman. That would only prove something if the equal transit time was some fundamental element of bernoulii's principle. In fact it is not. In fact, the air flowing over the "top" of the airfoil arrives at the trailing edge of the airfoil well before the air flowing beneath. This can be seen in wind tunnel photos and footage of pulsed smoke steamers flowing over air foils.
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