propeller

propeller is a type of fan which transmits power by converting rotational motion into thrust. It can be used to drive an aircraft ship, or the fluid within a pump. It consists of one or more blades about a central shaft and operates like a rotating screw or wing. A pressure difference between the forward and rear surfaces of the airfoil-shaped blade is produced and air or water accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's principle and Newton's third law. (information taken from wikipedia)