Lift to drag and angle of attack
Lift to drag and angle of attack
(OP)
For a given NACA airfoil is it available any formula which relates the (L/D) ratio with the angle of attack?
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
Lift to drag and angle of attack
|
RE: Lift to drag and angle of attack
Since you are asking I would assume you are not looking to come up with the theoretical equations, so check out www.worldofkrauss.com/ They have lots of Cl and Cd data for different AOAs for tons of foils. They allow you to compare several foils.
RE: Lift to drag and angle of attack
Every airfoil will behave slightly different, but if they're not to thick on may use some linear theories.
There are many theoretical texts on this. The drag should go quadratically with lift, while lift (before stalling) goes linear (slope about 2*pi) with the angle of attack.
Have a look at
http://en.wikipedia.org/wiki/Lift-induced_drag
And google on:
Parasite drag
Induced drag
The laminar bucket
Linear lift theory
A classical text on this issue is:
Abbott, Ira H., and Von Doenhoff, Albert E. (1959): Theory of Wing Sections. Dover Publications Inc., New York, Standard Book Number 486-60586-8
RE: Lift to drag and angle of attack
aafuni,
Frankly I was looking for a theoretical correlation, anyhow your link is very interesting.
RE: Lift to drag and angle of attack
I like that site to get some rough comparisons and narrow down my options before I move into the more in depth analysis.
RE: Lift to drag and angle of attack
i think the most you'll find is curve fits to experimental results.
the lift side is pretty easy, the drag side is quite complex ... 2D wing section or 3D wing ? a 3D wing adds "drag due to lift"