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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 ...
The high-bypass turbofan engines used on many modern airliners is an example of a very successful and popular use of ducted fan design. The duct increases thrust efficiency by up to 90% in most cases [citation needed], in comparison to a similar-sized propeller in free air. Ducted fans are quieter, and offer good opportunities for thrust vectoring.
A rim-driven thruster integrates an electric motor into a ducted propeller. The cylindrical duct acts as the stator, while the tips of the blades act as the rotor. They typically provide high torque and operate at low RPMs, producing less noise. The system does not require a shaft, reducing weight.
Though the term is most commonly applied to aircraft, its most ubiquitous propeller example is a common outboard motor for a small boat. “Pusher configuration” describes the specific (propeller or ducted fan ) thrust device attached to a craft, either aerostats ( airship ) or aerodynes (aircraft, WIG , paramotor , rotorcraft ) or others ...
A pump-jet, hydrojet, water jet, or jet drive uses a ducted propeller (axial-flow pump), centrifugal pump, or mixed flow pump to create a jet of water for propulsion. These incorporate an intake for source water and a nozzle to direct its flow out, generating momentum, and in most cases, employing thrust vectoring to steer the craft.
A ducted fan or propeller also has certain benefits at lower speeds but the duct needs to be shaped in a different manner than one for higher speed flight. More air is taken in and the fan therefore operates at an efficiency equivalent to a larger un-ducted propeller.
WASHINGTON (Reuters) -President-elect Donald Trump cannot ignore a law requiring Chinese-based ByteDance to divest its popular short video app TikTok in the U.S. by early next year or face a ban ...
An airbreathing jet engine (or ducted jet engine) is a jet engine in which the exhaust gas which supplies jet propulsion is atmospheric air, [1] which is taken in, compressed, heated, and expanded back to atmospheric pressure through a propelling nozzle. [2]