Grades 3–5 · Machines
How does a pilot change an airplane's direction?
An airplane has small moving surfaces on its wings and tail. Air flows over these surfaces as the plane flies. Moving a surface changes the air's push. Because these pushes act away from the plane's center of mass, they can turn the whole airplane. There are three main kinds of turning motion.
In the diagramMoving surfaces change air forces and turn the planeTop view: the nose points upwardAilerons: rollRudder: yawElevator:pitchRudder isverticalAilerons mainly produce roll.Forces create turning moments about the center of mass.
Roll tilts one wing down and the other up. Small surfaces called ailerons sit near the outer rear edges of the wings. They usually move in opposite directions, changing the upward forces on the two wings differently. Pitch raises or lowers the nose. The elevator, on the horizontal tail of a conventional plane, changes the tail's force to produce this rotation.
Yaw swings the nose from side to side. The rudder is a moving surface on the upright tail. It changes a sideways air force and produces this turning motion. These controls work together: the rudder alone does not steer an airplane exactly like a car. A coordinated turn also uses the bank of the wings and other control adjustments. By shaping the forces of flowing air, a pilot can guide a large machine through three-dimensional space.
About this explanation
Starting knowledge: Distinguish tilting, nose-up motion and side-to-side turning.
Sources
- NASA Glenn Research Center — Aircraft Rotations
- Federal Aviation Administration — Pilot's Handbook of Aeronautical Knowledge: Flight Controls