ABSTRACT
Stall also affects helicopters. When a helicopter’s main rotor spins, the blades moving in the same direction as the aircraft are called the advancing blades, and the blades traveling in the opposite direction are called the retreating blades. Air flows over the advancing blades faster than it flows over the retreating blades, so the advancing blades experience greater lift. If the airflow over the retreating blades is slow enough, they can stall. The helicopter experiences a sudden loss of lift called a retreating blade stall, but only on one side. The advancing blades still produce lift, so the helicopter rolls over to one side.
