Author: David Alan Conner
Publisher:
ISBN:
Category : Acoustical engineering
Languages : en
Pages : 68
Book Description
An experiment has been performed to investigate the reduction of high-speed impulsive noise for the UH-1H helicopter by using an advanced main rotor system. The advanced rotor system had a tapered blade planform compared with the rectangular planform of the standard rotor system. Models of both the advanced main rotor system and the UH-1H standard main rotor system were tested at 1/4 scale in the Langley 4- by 7-Meter Tunnel. In-plane acoustic measurements of the high-speed impulsive noise demonstrated that the advanced rotor system on the UH-1H helicopter reduced the high-speed impulsive noise by up to 20 dB, with a reduction in overall sound pressure level of up to 6 dB. (Author).
Reduction of High-speed Impulsive Noise by Blade Planform Modification of a Model Helicopter Rotor
Author: David Alan Conner
Publisher:
ISBN:
Category : Acoustical engineering
Languages : en
Pages : 68
Book Description
An experiment has been performed to investigate the reduction of high-speed impulsive noise for the UH-1H helicopter by using an advanced main rotor system. The advanced rotor system had a tapered blade planform compared with the rectangular planform of the standard rotor system. Models of both the advanced main rotor system and the UH-1H standard main rotor system were tested at 1/4 scale in the Langley 4- by 7-Meter Tunnel. In-plane acoustic measurements of the high-speed impulsive noise demonstrated that the advanced rotor system on the UH-1H helicopter reduced the high-speed impulsive noise by up to 20 dB, with a reduction in overall sound pressure level of up to 6 dB. (Author).
Publisher:
ISBN:
Category : Acoustical engineering
Languages : en
Pages : 68
Book Description
An experiment has been performed to investigate the reduction of high-speed impulsive noise for the UH-1H helicopter by using an advanced main rotor system. The advanced rotor system had a tapered blade planform compared with the rectangular planform of the standard rotor system. Models of both the advanced main rotor system and the UH-1H standard main rotor system were tested at 1/4 scale in the Langley 4- by 7-Meter Tunnel. In-plane acoustic measurements of the high-speed impulsive noise demonstrated that the advanced rotor system on the UH-1H helicopter reduced the high-speed impulsive noise by up to 20 dB, with a reduction in overall sound pressure level of up to 6 dB. (Author).
Reduction of High-speed Impulsive Noise by Blade Planform Modification of a Model Helicopter Rotor
Author: David Alan Conner
Publisher:
ISBN:
Category : Acoustical engineering
Languages : en
Pages : 68
Book Description
Publisher:
ISBN:
Category : Acoustical engineering
Languages : en
Pages : 68
Book Description
Helicopter Impulsive Noise: Theoretical and Experimental Status
Author: F. H. Schmitz
Publisher:
ISBN:
Category :
Languages : en
Pages : 110
Book Description
The theoretical and experimental status of helicopter impulsive noise is reviewed. The two major source mechanisms of helicopter impulsive noise are addressed: high-speed impulsive noise and blade-vortex interaction impulsive noise. A thorough physical explanation of both generating mechanisms is presented together with model and full-scale measurements of the phenomena. Current theoretical prediction methods are compared with experimental findings of isolated rotor tests. The noise generating mechanisms of high speed impulsive noise are fairly well understood - theory and experiment compare nicely over Mach number ranges typical of today's helicopters. For the case of blade-vortex interaction noise, understanding of noise generating mechanisms and theoretical comparison with experiment are less satisfactory. Several methods for improving theory-experiment are suggested.
Publisher:
ISBN:
Category :
Languages : en
Pages : 110
Book Description
The theoretical and experimental status of helicopter impulsive noise is reviewed. The two major source mechanisms of helicopter impulsive noise are addressed: high-speed impulsive noise and blade-vortex interaction impulsive noise. A thorough physical explanation of both generating mechanisms is presented together with model and full-scale measurements of the phenomena. Current theoretical prediction methods are compared with experimental findings of isolated rotor tests. The noise generating mechanisms of high speed impulsive noise are fairly well understood - theory and experiment compare nicely over Mach number ranges typical of today's helicopters. For the case of blade-vortex interaction noise, understanding of noise generating mechanisms and theoretical comparison with experiment are less satisfactory. Several methods for improving theory-experiment are suggested.
NASA Technical Paper
Author:
Publisher:
ISBN:
Category : Astronautics
Languages : en
Pages : 532
Book Description
Publisher:
ISBN:
Category : Astronautics
Languages : en
Pages : 532
Book Description
NASA Technical Memorandum
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 402
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 402
Book Description
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 316
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 316
Book Description
Model Helicopter Rotor High-speed Impulsive Noise: Measured Acoustics and Blade Pressures
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 40
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 40
Book Description
Evaluation of a Doubly-swept Blade Tip for Rotorcraft Noise Reduction
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 74
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 74
Book Description
The Shock and Vibration Digest
Author:
Publisher:
ISBN:
Category : Shock (Mechanics)
Languages : en
Pages : 664
Book Description
Publisher:
ISBN:
Category : Shock (Mechanics)
Languages : en
Pages : 664
Book Description
Correlation of Helicopter Impulsive Noise from Blade-vortex Interaction with Rotor Mean Inflow
Author: Andrew B. Connor
Publisher:
ISBN:
Category : Helicopters
Languages : en
Pages : 28
Book Description
Publisher:
ISBN:
Category : Helicopters
Languages : en
Pages : 28
Book Description