5. Airfoil data (15 points) A model wing of constant chord length is placed in a low-speed subsonic wind tunnel, spanning the test section. The wing has an NACA 2418 airfoil and a chord length of 4 ft. The flow in the test section as at a velocity of 100 ft/s at standard sea-level conditions. If the wing is at a 4 degree angle of attack, calculate (a) c₁, Cd, and Cmc/4, and (b) the lift, drag, and moment about the quarter chord, per unit span.