Leading edge and trailing edge of an airfoil rotor blade
 

Hi all. I have the airfoils that consist a rotor blade (in 3D). Each airfoil contains 428 points approximatively which I have their cartesian coordinates (x,y,z). Because I am in 3D, I have difficulties finding for each airfoil, which point is the leading edge and which point is the trailing edge. Do yo have any suggestion please ?

(I need this to prepare the file blade.curve for Turbogrid)

Thank you very much for your help, Petro.