Ok , so using this formula

http://en.wikipedia.org/wiki/Downforce <-- wont copy paste .

I'm trying to find what the angle of attack should be on a wing .

according to this http://en.wikipedia.org/wiki/Angle_of_attack
the problem is on a car's wing the angle of attack is the opposite as shown here . so does that mean that it would be negative angle ,

for example .. if said wing is said to have 15 degrees angle . how would you plot that into the equation ?

as a 15* ?? do you plot it as a decimal .54, fraction ? 360/15 ? is it negative since the angle is opposite as to what it shown for aircraft which is where normally the equation is used for ?

 

The angle of attack is dependant on the conditions and the desired amount of downforce.


The manufacturer should have that info available to you if they are any good.

Example: APR APR Performance - GTC-300 - CFD Data & Analysis

 

Yes I have the angles the wings settings have .


it also gives CL , per setting , at 15* it has -.075 CL so if at 15* its at that would it be redundant to plug the angle of attack again since it was already calculated into the lift coefficiency ?