Helicopter Noise Generation and Detectability.
Heller, H. (1990) Helicopter Noise Generation and Detectability. NATO/CCMS Aircraft Noise Meeting, 10 May 1990, Erding.
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A helicopter is easily detected and identified by its acoustic signature. During high speed flight and under certain landing approach flight conditions there occurs the helicopter-characteristic periodic impulsive noise ("blade slap"). In the absence of such dominating impulsive noise phenomena, the periodic low-frequency sound of the main-rotor and the more high pitch "propeller-like" sound of the tail-rotor acoustically typifies a helicopter. There are a number of noise generating mechanisms at work, individually related to the operation of the main-rotor, of the tail-rotor, and/or to the interaction of the two. This presentation discusses the physics of these various mechanisms and shows ways and means of how to reduce the acoustic detactability and the acoustic annoyance caused by a helicopter in flyover.
|Document Type:||Conference or Workshop Item (Speech)|
|Title:||Helicopter Noise Generation and Detectability.|
|Keywords:||Helicopter Noise, Acoustic Annoyance, Acoustic Detectability, Rotor I mpulsive Noise, Main Rotor Noise, Tail Rotor Noise, Rotor Interaction Noise|
|Event Title:||NATO/CCMS Aircraft Noise Meeting, 10 May 1990, Erding|
|HGF - Research field:||UNSPECIFIED|
|HGF - Program:||no assignment|
|HGF - Program Themes:||no assignment|
|DLR - Research area:||UNSPECIFIED|
|DLR - Program:||no assignment|
|DLR - Research theme (Project):||L - The Quiet and Comfortable Rotorcraft|
|Location:||Köln-Porz , Braunschweig , Göttingen|
|Institutes and Institutions:||Institute of Aerodynamics and Flow Technology > Institut für Entwurfsaerodynamik|
|Deposited By:||elib DLR-Beauftragter|
|Deposited On:||03 Apr 2006|
|Last Modified:||27 Apr 2009 10:04|
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