A propeller works by rotating and pulling in air from in front of the airplane. As the air flows over the top and bottom of the blade, it creates a difference in air pressure. This difference creates thrust and enables the airplane to move forward.
A propeller consists of multiple blades, each radiating out from a central point. An internal combustion engine provides power to the pistons, which move up and down to turn the crankshaft, which in turn rotates the propellers.
The cross-section of a propeller blade is shaped like a wing; both sides are curved rather than flat. As the blade spins and air moves over the curves, the air pressure around the blade changes. On a wing, this change in pressure creates lift that allows the airplane to move upward. On a propeller, the orientation and the spinning motion allow the airplane to move forward. This motion is called thrust.
The orientation of the propeller blades is designed to provide maximum thrust. Usually, the blades have a slight twist that compensates for the difference in speed between the base and the tip.
Propellers balance the drag on the airplane as it moves through the air. Many airlines used fixed-position propeller blades, while others move to account for different conditions.