View Single Post
Old 07-29-2009 | 08:11 PM
  #4  
ryan1234's Avatar
ryan1234
Gets Weekends Off
 
Joined: Jun 2008
Posts: 1,398
Likes: 0
From: USAF
Default

Originally Posted by shdw
How can it not be included but figure into which implies included in?



Woah, this is an accepted theory, though not law due to complexities far beyond the scope of what you posted. It is an accurately tested and accepted theory where [Cl = 2 pi AOA]. Even so, the "real Cl" as you put it since this is only the "tested" one, still goes up, even with the newest Cl theories. There has not, to my knowledge, been a theory that proves Cl not going up in ground effect. Though I would be glad to enlightened if there is one.

Airfoil - Wikipedia, the free encyclopedia

Here is an advanced theory for a "more accurate Cl" if you would like to see some advancing theories on this topic:

http://pdf.aiaa.org/jaPreview/JA/1988/PVJAPRE45711.pdf


Otherwise, nice post, the methods aren't unconventional they are just the other factors that cause lift: impact, bernoulli, and deflected air.

CL = 2*pi*angle

:is for smaller AoAs, thin airfoils, and in a windtunnel. Ref:
Modern Lift Equation

It is fine and we can use it for various things - which I do, but it must be noted that pragmatic values may vary and should be no suprise. Fluid (air) is different in wind tunnels than in the open atmosphere. Net vs. Total can be slightly confusing as well.

I would venture to say that few people (especially student pilots) have an accurate picture of how Bernoulli's principle works and that which doesn't work pertaining to airfoils. This is especially important conducting tests with windtunnels.

An interesting website on the blunders of blindly using Bernoulli's principle to determine lift:

Aeronautics.ws - Aeronautical Engineering Blunder #1
Reply