RESONANT BLADES USING AN APERTURE FOR CANCELLATION OF PROPELLER GENERATED NOISE

RESONANT BLADES USING AN APERTURE FOR CANCELLATION OF PROPELLER GENERATED NOISE

An exemplary apparatus minimizes an aircraft propeller noise having an associated frequency and a corresponding wavelength. A resonant tone produced on the propeller blade elicits a sound with substantially the same frequency as the associated frequency of the offending source. The resonant tone is...

Ausführliche Beschreibung

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Bibliographische Detailangaben
1. Verfasser: LINCH, Jonathon J
Format: Patent
Sprache:eng ; fre ; ger
Schlagworte:
AEROPLANES
AIRCRAFT
AVIATION
COSMONAUTICS
HELICOPTERS
PERFORMING OPERATIONS
TRANSPORTING
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Beschreibung
Zusammenfassung:An exemplary apparatus minimizes an aircraft propeller noise having an associated frequency and a corresponding wavelength. A resonant tone produced on the propeller blade elicits a sound with substantially the same frequency as the associated frequency of the offending source. The resonant tone is powered by an inflow of air in or across an aperture of a resonant structure during the rotation of the blade and the aperture has an opening from which the sound is emitted. The resonant structure is dimensioned to generate a sound with substantially the same frequency as the offending source. The aperture is located on the blade with the opening a distance from a target origin of the noise that is substantially one half of the wavelength of the noise so that the sound arrives at the target origin of the noise substantially 180 degrees out of phase with the noise.