Airplane wings possess a unique and special shape known as an “airfoil”. As the wings move through the air, the air is split as it passes above (and below) the wing. The upper surface of the wing is shaped in a way so that the air that’s forced up and over the top both speeds up and stretches out, thereby decreasing the air pressure that exists above the wing. The air that flows below the wing moves in more of a straight line, meaning that its pressure and speed remains the same/relatively unchanged. Due to the fact that high air pressure likes to move towards low air pressure, the air below the wing winds up pushing upwards towards the air that’s above the wing. And, because the wing is sandwiched in the middle of these two pressures, the wing is lifted as the air below pushes it upwards. The faster the plane moves, the more lift there is and, when the force of the lift gets to a point where it exceeds the force of gravity, the airplane is able to fly.
An airfoil is comprised of a leading edge (which is the end that meets the air first), a trailing edge (the end of the airfoil, where the air with high pressure meets the air with low pressure), a chord (the imaginary line extending from the leading edge to the trailing edge), and a camber (the curve on top and bottom of the airfoil). Aside from the wings of a plane, other common examples of an airfoil are propellers, fans, turbines, and helicopter rotor blades. Airfoils also exist in flying and swimming creatures, as well as sessile organisms such as sea urchins.
Check back next time when we discuss the various types – and advantages – of airfoils! Have questions? Let us know…we’re happy to help!