Powered aircraft

A powered aircraft is an aircraft that uses onboard propulsion with mechanical power generated by an aircraft engine of some kind.

Aircraft propulsion nearly always uses either a type of propeller, or a form of jet propulsion. Other potential propulsion techniques such as ornithopters are very rarely used.

A propeller or airscrew comprises a set of small, wing-like aerofoil blades set around a central hub which spins on an axis aligned in the direction of travel. The blades are set at a pitch angle to the airflow, which may be fixed or variable, such that spinning the propeller creates aerodynamic lift, or thrust, in a forward direction.

A tractor design mounts the propeller in front of the power source, while a pusher design mounts it behind. Although the pusher design allows cleaner airflow over the wing, tractor configuration is more common because it allows cleaner airflow to the propeller and provides a better weight distribution.

Contra-rotating propellers have one propeller close behind another on the same axis, but rotating in the opposite direction.

A variation on the propeller is to use many broad blades to create a fan. Such fans are usually surrounded by a ring-shaped fairing or duct, as ducted fans.

Many kinds of power plant have been used to drive propellers.

The earliest designs used man power to give dirigible balloons some degree of control, and go back to Jean-Pierre Blanchard in 1784. Attempts to achieve heavier-than-air man-powered flight did not succeed fully until Paul MacCready's Gossamer Condor in 1977.

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Wikipedia