发明授权
US4410150A Drag-reducing nacelle 失效
减拖机舱

Drag-reducing nacelle
摘要:
A wing-mounted gas turbofan engine is provided with an exhaust system that reduces airflow drag during subsonic aircraft flight operation. The system reduces drag by turning the engine bypass exhaust stream away from the underside of the airplane wing to lessen its tendency to reduce air pressure under the wing. Low pressure below the airplane wing has a detrimental effect on wing lift which, in turn, causes greater airflow drag. The exhaust system construction lessens its pressure lowering influence by first, inwardly curving the exhaust system exit to turn the bypass flow away from the airplane wing; second, by predetermining the location of a nozzle throat within the bypass stream to control exit exhaust pressure so as to match outside air pressure and third, by decreasing the diameter of a portion of the engine nacelle just downstream of the bypass exhaust stream exit to provide a flow region for the exhaust that is further from the airplane wing.
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