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A ducted propeller, also known as a Kort nozzle, is a marine propeller fitted with a non-rotating nozzle. It is used to improve the efficiency of the propeller and is especially used on heavily loaded propellers or propellers with limited diameter. It was developed first by Luigi Stipa (1931) and later by Ludwig Kort (1934). The Kort nozzle is ...
In aeronautics, a ducted fan is a thrust-generating mechanical fan or propeller mounted within a cylindrical duct or shroud. Other terms include ducted propeller or shrouded propeller . [ 1 ] When used in vertical takeoff and landing ( VTOL ) applications it is also known as a shrouded rotor .
Propellers are used to pump fluid through a pipe or duct, or to create thrust to propel a boat through water or an aircraft through air. The blades are shaped so that their rotational motion through the fluid causes a pressure difference between the two surfaces of the blade by Bernoulli's principle which exerts force on the fluid. [2]
The mechanical arrangement may be a ducted propeller (axial-flow pump), a centrifugal pump, or a mixed flow pump which is a combination of both centrifugal and axial designs. The design also incorporates an intake to provide water to the pump and a nozzle to direct the flow of water out of the pump.
While there is a loss in efficiency as the fan is drawing on a smaller area of the free stream and so using less air, this is balanced by the ducted fan retaining efficiency at higher speeds where conventional propeller efficiency would be poor. A ducted fan or propeller also has certain benefits at lower speeds but the duct needs to be shaped ...
1871 Planophore A Farman MF.11, showing the classic Farman configuration with engine between tail booms Buhl A-1 Autogyro, the first pusher autogyro The post-WWII Convair B-36 was unusual in its size, era, number of engines, and combining both propeller and jet propulsion, with six radial piston and four jet engines Typical of many UAVs, the General Atomics MQ-9 Reaper has a propeller at the ...
The Piasecki X-49 "SpeedHawk" is an American four-bladed, twin-engined experimental high-speed compound helicopter developed by Piasecki Aircraft.The X-49A is based on the airframe of a Sikorsky YSH-60F Seahawk, but utilizes Piasecki's proprietary vectored thrust ducted propeller (VTDP) design and includes the addition of lifting wings.
Variation of Pressure and Velocity of Flow through a Propeller disc. [1] In the figure, the thickness of the propeller disc is assumed to be negligible. The boundary between the fluid in motion and fluid at rest is shown. Therefore, the flow is assumed to be taking place in an imaginary converging duct [1] [2] where: D = Diameter of the ...