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Propeller walk single propeller in reverse. Propeller walk (also known as propeller effect, wheeling effect, paddle wheel effect, asymmetric thrust, asymmetric blade effect, transverse thrust, prop walk) is the term for a propeller's tendency to rotate about a vertical axis (also known as yaw motion). The rotation is in addition to the forward ...
The momentum theory or disk actuator theory – a theory describing a mathematical model of an ideal propeller – was developed by W.J.M. Rankine (1865), Alfred George Greenhill (1888) and Robert Edmund Froude (1889). The propeller is modelled as an infinitely thin disc, inducing a constant velocity along the axis of rotation.
Counter-rotating propellers World War I Linke-Hofmann R.I German heavy bomber (1917) with counter-rotating propellers He 177A Greif with counter-rotating propellers. Counter-rotating propellers (CRP) are propellers which turn in opposite directions to each other. [1] They are used on some twin- and multi-engine propeller-driven aircraft.
Feathered propeller on the outboard TP400 turboprop of an Airbus A400M. On most variable-pitch propellers, the blades can be rotated parallel to the airflow to stop rotation of the propeller and reduce drag when the engine fails or is deliberately shut down. This is called feathering, a term borrowed from rowing. On single-engined aircraft ...
Aircraft engine performance refers to factors including thrust or shaft power for fuel consumed, weight, cost, outside dimensions and life. It includes meeting regulated environmental limits which apply to emissions of noise and chemical pollutants, and regulated safety aspects which require a design that can safely tolerate environmental hazards such as birds, rain, hail and icing conditions.
Contra-rotating propellers Contra-rotating propellers on the Rolls-Royce Griffon-powered P-51XR Mustang Precious Metal at the 2014 Reno Air Races. Aircraft equipped with contra-rotating propellers (CRP) [1] coaxial contra-rotating propellers, or high-speed propellers, apply the maximum power of usually a single piston engine or turboprop engine to drive a pair of coaxial propellers in contra ...
The relevance for gas turbine-powered aircraft is the use of a secondary jet of air with a propeller or, for jet engine performance, the introduction of the bypass engine. The overall efficiency of the jet engine is thermal efficiency multiplied by propulsive efficiency ( η o = η t h η p r {\displaystyle \eta _{o}=\eta _{th}\eta _{pr}} ).
Contra-rotating propellers should not be confused with counter-rotating propellers, a term which describes propellers rotating in opposite directions but sitting apart from each other on separate shafts instead of sharing a common axis. Tandem-rotor helicopters such as the CH-47 Chinook also use a counter-rotating arrangement. The efficiency of ...