Though airplane flight may appear miraculous, there is science behind it. Airplanes stay up in the air because of the aerodynamic force referred to as lift. Airplane lift, generated by each part of an aircraft, is a force that works in direct opposition to the weight of an aircraft. It has to do with the movement of air, which is typically referred to as a fluid in aerodynamic descriptions. This fluid acts on the plane to allow it to rise into the air and stay there, as long as several conditions are met.
Lift is present when a solid object deflects or turns a moving flow of fluid. Flow turns in one direction, while lift is produced in the opposite direction. Solid surfaces of all types are able to cause the flow to turn aside, ensuring that airplanes stay up in the air. For example, both the upper and lower portions of an airplane’s wing surface are important in deflecting the flow of fluid.
Motion is also vital in ensuring that airplanes don’t come crashing down. Without movement, lift is not generated. There must also be a velocity difference between the plane and the fluid. Airplane lift is generated perpendicular to motion, so as the plane moves forwards, lift is generated upward. Motion does not act alone when airplanes fly through the sky, however; drag opposes motion, contributing to the science of flight as well.
Besides lift, motion, and drag, weight and thrust are also important in making sure airplanes stay in the sky. The weight of an airplane is spread out, keeping it balanced. It is this force that pulls a plane toward the ground. Thrust, provided by the airplane’s engines, moves it forward and drag slows it down. Without these forces, each working in its own way, an airplane could not fly.