NACA (“NACK-uh”) developed a standard set of these devices with four or five digit identifiers. Effects like downwash for finite versions of these objects are simulated by modelling these objects as an infinite set of filaments in a theory named for Prandtl (“PRAWN-tull”). The force per unit length on these devices is proportional to the line integral of the tangential velocity around them, according to the Kutta–Joukowski (“KOO-tuh zhoo-KOFF-skee”) theorem. The chord line connects these devices’ leading and trailing edges, while the difference in convexity of their upper and lower surfaces is called their camber. These objects enter a stall when they exceed the critical angle of attack. (10[1])For 10 points, name these devices that generate lift while moving through air. ■END■