An airfoil can be any object that takes the shape of a cross-sectional blade, wing, or sail. The airfoil is designed in a shape that ensures faster fluid movement below it and slower fluid movement above it hence creating lift. The airfoil concept is one of the most remarkable inventions of man – pretty any object that needs to travel through fluid utilizes the airfoil in one way or another. If you observe nature more closely, you will discover that man didn’t hatch this idea out of the blue – he simply observed how birds flew and made something that could mimic their wings.
How an airfoil works
The airfoil operates on the concept of pressure variance due to difference in speed of fluids above and below a specially designed object referred to as an airfoil. As you would expect, an airfoil produces aerodynamic forces when traveling through fluids. The force that is perpendicular to the airfoil’s direction of motion creates lift. The force that is parallel to the airfoil’s direction of motion creates drag. The shape of the airfoil ensures that the fluid travels with a higher velocity on the suction surface (upper surface) to create low static pressure and with low velocity on the pressure surface (lower surface) to create high static pressure. This variance in pressure between the bottom and top regions of the airfoil causes the force of lift to exert thrust on the wing. These forces don’t work alone though, the airfoil must remain within the angle of attack (the angle between the airfoil’s chord and the relative airflow) which lies in the range of 15 and 20 degrees. The airfoil will stall at angles outside this range. Other factors such as the thinness of the airfoil can influence its effectiveness. The material used to make the airfoil too can have a significant effect on its effectiveness with aluminum being the most preferred material.