02-01-2020 дата публикации
Номер: US20200002014A1
There is provided a propulsion system for an aircraft, the system having a low-fan-pressure-ratio engine configured to be mounted, in a forward over-wing-flow installation, to a wing of the aircraft. The engine has a core, a variable pitch fan, and a nacelle having a nacelle trailing edge with a top-most portion positioned above a wing leading edge. The engine has an L/D ratio of the nacelle in a range of from 0.6 to 1.0, and a fan-pressure-ratio in a range of from 1.10 to 1.30. The forward over-wing-flow installation enables, during all flight phases of the aircraft, a fan flow exhaust to flow behind the nacelle, and to be bifurcated by the wing leading edge, so the fan flow exhaust flows both over the wing and under the wing. During a cruise flight phase of the aircraft, the engine minimizes scrubbing drag of the fan flow exhaust to the wing. 1. A propulsion system for an aircraft , comprising: a core having a first end and a second end;', 'a variable pitch fan coupled to the first end of the core;', 'a nacelle surrounding the variable pitch fan and a portion of the core, the nacelle having a nacelle leading edge and a nacelle trailing edge, the nacelle trailing edge having a top-most portion configured to be positioned above a wing leading edge of the wing, and the nacelle configured to be positioned, in its entirety, at a forward location in front of the wing leading edge;', 'a length to diameter (L/D) ratio of the nacelle in a range of from 0.6 to 1.0; and', 'a fan-pressure-ratio in a range of from 1.10 to 1.30,, 'a low-fan-pressure-ratio engine configured to be mounted, in a forward over-wing-flow installation, to a wing of the aircraft, the low-fan-pressure-ratio engine comprisingwherein the forward over-wing-flow installation of the low-fan-pressure-ratio engine of the propulsion system enables, during all flight phases of the aircraft, a fan flow exhaust, exhausted by the variable pitch fan, to flow behind the nacelle, and to be bifurcated by the wing ...
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