How a Helicopter Works

The rotor of a helicopter serves as both wings and propeller. Lift is produced by changes in air pressure caused by the spinning blades of the rotor. As a blade moves, air flows faster over its curved upper surface than over its flat lower surface. This results in reduced air pres­sure above the blade; the difference in air pressure produces lift.

The helicopter pilot can control the amount of lift by altering the angle of the rotor blade. If the blade is tilted so that more air presses up against the bot­tom of the blade, the air pressure beneath it increases, and so does the helicopter’s lift.

A helicopter can fly straight up and forward or backward. It can hover, fly straight down, and fly sideways, but it cannot glide. A helicopter pilot can never let go of the controls-just to hover requires the pilot to make con­stant tiny corrections to maintain the correct position.