How Do Airplanes Fly?

The first half of the equation of flight has to do with three factors: lift, force and gravity. To dive into these factors, we need to look into the physics of airplane flight and Newton’s Third Law of Motion: for every action, there is an equal and opposite reaction. The main key here is balance. To achieve flight we must first create forward thrust and lift to generate air pressure beneath the wings that will, in turn, lift the plane. This lift must create an imbalance where there is more lift or force upward than there is gravity pushing downward. Airplane wings are shaped with an angle of attack that maximises the amount of air hitting the bottom of the wing. Too much tilt and the airflow around the wings becomes too choppy and irregular and a plane fails to sustain lift and fly correctly. A 15 degree tilt tends to be the maximum sustainable angle for aerodynamic flight.

Once a plane is airborne, staying in the air is achieved by maintaining a balance between this lift and gravity, which establishes a state of having no net force applied to the aircraft. Where lift and gravity deal with the up and the down, thrust and drag work on the horizontal plane. Forward thrust must counteract the drag on a plane. Drag is the force of wind pushing the airplane back and is caused by all parts of the plane that block wind flow. A plane is propelled forward by propellers or jet engines and this forward motion is essential to sustained flight. When the force of thrust is higher than the drag, forward motion occurs.

The same way that a top/bottom air pressure imbalance causes lift, a left/right imbalance in the amount of air pressure exerted on the wings, enables the plane to steer. Much like a bird, a plane steers left or right by dropping one wing lower than the other. This wing drop increases the force of air on the one wing compared to the other and steering is possible. You now know how a plane goes up and down, forward and back, and left and right.

1. dany geller
2. Posted on January 14, 2020
aerospace