Forces of Flight

Understanding how things fly begins by learning about the Four Forces of Flight.

When an airplane flies, the wing is designed to provide enough Lift to overcome the airplane’s Weight, while the engine provides enough Thrust to overcome Drag and move the airplane forward. And the Thrust of a rocket engine overcomes the Weight of the object to move the rocket forward.

Increasing the weight of an aircraft affects the amount of lift needed. In turn, a larger wing would provide more lift, but that would increase the amount of drag and therefore increase the amount of thrust needed. The forces of flight are interconnected, and a change in one affects the others.

Discovery lands at NASA's Kennedy Space Center. The Space Shuttle flies in two very different environments: Earth's atmosphere and low Earth orbit. But the forces of flight act on it no matter where it is. The four forces of flight affect the Shuttle only when it’s in Earth’s atmosphere. When it’s in low Earth orbit, only weight and thrust act on it.

Credit: NASA