What are Lift and Drag coefficients?
A. The Lift is the force at right-angles to the airflow. The Drag is the force parallel to the airflow. Both parameters depend on airfoil shape, and reynolds number and angle of attack. You need windtunnel test results to assess the best point on the curves to choose for your design angle of attack, lift and drag. The list chooser for airfoil will suggest an optimum value to use for angle of attack and lift. Drag will often be around 0.002. You want to maximise Cl cubed divided by Cd squared.
