Aircraft Propellers | Aircraft Systems

Aircraft Propellers

Since the first powered flight, propellers have been used to convert aircraft engine power into thrust. Although most modern transport category aircraft are powered by turbojet or turbofan engines, many of the aircraft in use today are propelled by one or more propellers driven by either a turbine or reciprocating engine. Regardless of engine type, the propeller converts engine power to aircraft thrust. As an aircraft maintenance technician, you must have a thorough understanding of the basic principles, maintenance, and repair of propeller systems.

Almost all early aircraft designs used propellers to create thrust. At the end of the 19th century, many unusual and innovative propeller designs were tried on flying machines. Early propeller designs included simple fabric-covered wooden paddles and elaborate multiblade wire-braced designs. As aeronautical science developed, propeller designs evolved from flat boards that pushed air backward to airfoils that produced lift to pull aircraft forward.

Propeller design developed with new materials that made possible thinner airfoil sections with greater strength. Because of structural strength, aluminum alloys have been used widely as a structural material in the majority of aircraft propellers. However, several varieties of propellers in still in service that are constructed of wood.

Propeller designs continue to improve through the use of new airfoil shapes, composite materials, and multi-blade configurations. Recent improvements include the use of composite materials to produce laminar flow symmetrical airfoils and scimitar propeller blade designs.