CL-alpha 3D

[joes123]

I am currently trying to calculate 3D CL values to compare with my 2D xfoil data. I understand that the 3D values will have a lower CLmax (~90%) with a stall alpha which is higher.

I have a dCl/dalpha for my 2D of 0.1132 (per degree) and Clmax of 1.667. But require a 3D CL-alpha plot. How can I do this?

J

 

[moon161]

Design the wing & fuselage, I think. At least determine the AR. The 3d value have to do with tip & fuselage interactions that are determined by the yet to be known 3rd dimension.

 

[joes123]

I have a AR of 9.27, I am trying to theoretically calculate the 3D cl-alpha plot for the Piper PA-38 Tomahawk if this helps?

 

[moon161]

http://www.edforall.net/index.php/e...echanics-ii/1664-elliptical-lift-distribution

 

[rb1957]

a pretty quick search of wiki lead to "lifting line theory" which includes ...

CL3d = CLa*(AR/(AR+2)*a

CLa = 2D lift curve slope
a = AoA
AR = aspect ratio