What is the purpose of the airfoil's shape?

The shape of an airfoil is specifically designed to create a pressure difference between the upper and lower surfaces as air flows over it. This pressure difference is crucial for generating lift, which allows an aircraft to rise off the ground and remain in flight. The airfoil's curvature and angle of attack affect how air moves around it, leading to a higher velocity of air over the top surface compared to the bottom surface. According to Bernoulli's principle, this higher velocity results in lower pressure above the airfoil, while the relatively stagnant air below creates higher pressure. The combination of these pressures produces the lift necessary for flight.

While reducing drag is certainly an important design consideration, the primary function of the airfoil shape is to generate lift through this pressure difference. Aesthetics and engine efficiency, while they may play roles in the overall aircraft design, are not the core purposes of an airfoil's shape.