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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 or backward acceleration.
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 ...
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.
An azimuthing propeller is a propeller that turns around the vertical axis. The individual airfoil-shaped blades turn as the propeller moves so that they are always generating lift in the vessel's direction of movement. This type of propeller can reverse or change its direction of thrust very quickly.
Diameter of the propeller. The propeller advance ratio or coefficient is a dimensionless number used in aeronautics and marine hydrodynamics to describe the relationship between the speed at which a vehicle (like an airplane or a boat) is moving forward and the speed at which its propeller is turning.
A Soviet Ka-32 helicopter with coaxial contra-rotating rotors, in 1989. Contra-rotating, also referred to as coaxial contra-rotating, is a technique whereby parts of a mechanism rotate in opposite directions about a common axis, usually to minimise the effect of torque.
Betz (1921) provided an approximate correction to momentum "Rankine–Froude actuator-disk" theory [4] to account for the sudden rotation imparted to the flow by the actuator disk (NACA TN 83, "The Theory of the Screw Propeller" and NACA TM 491, "Propeller Problems"). In blade element momentum theory, angular momentum is included in the model ...
The stator concentrates the thrust in axial direction and reduces energy wasted in the tangential flow (therefore eliminating torque on the hull). The number of blades in the rotor and stator will typically be two different prime numbers to avoid standing waves. The blades in the rotor or the stator may be angled to further reduce noise.