ABSTRACT
If an aircraft engine breaks down during a flight, air rushing through the propeller blades keeps the propeller spinning. A propeller that spins freely in this way causes drag. Extra drag on one side of a plane acts like a brake and makes the plane turn to that side. Some propellers are designed to prevent this from happening. They have blades with edges that can be turned toward the air to cut their drag. This is called feathering. Some planes can actually reverse their propeller blades so that they blow air forward instead of backward, a process called reverse thrust. It helps cargo planes, such as the military C-130 Hercules, stop a short distance after landing.
