For a symmetric aerofoil, 0 angle of attack is 0 lift. For an asymmetric - there is (some) lift, which comes entirely from the suction side. https://www.wolfra

For a symmetric aerofoil, 0 angle of attack is 0 lift. For an asymmetric - there is (some) lift, which comes entirely from the suction side. https://www.wolframalpha.com/input/?i=NACA+6409+airfoil&assumption=%7B%22F%22%2C+%22AirfoilAngleOfAttack%22%2C+%22a%22%7D+-%3E%220%22 https://www.wolframalpha.com/input/?i=NACA+6409+airfoil&assu...