about Lift-Drag coefficient
 

i'm analysing Cl,Cd of airfoil but when i'm increase the airfoil cord length (same profile-NACA2515) the Cl,Cd is increase too

is this what suppose to be?

Re: about Lift-Drag coefficient
 

Everything else equal, changing the chord length will change the Cd and Cl. When you change the chord length, you are also changing the Reynolds Number and consequentially the lift and drag characteristics of the airfoil