Author: Donald P. GarberPublisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 36
Book Description
En Route Noise Levels from Propfan Test Assessment Airplane
Author: Donald P. GarberPublisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 36
Book Description
En Route Noise Levels from Propfan Test Assessment Airplane
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781722202309
Category :
Languages : en
Pages : 32
Book Description
The en route noise test was designed to characterize propagation of propfan noise from cruise altitudes to the ground. In-flight measurements of propfan source levels and directional patterns were made by a chase plane flying in formation with the propfan test assessment (PTA) airplane. Ground noise measurements were taken during repeated flights over a distributed microphone array. The microphone array on the ground was used to provide ensemble-averaged estimates of mean flyover noise levels, establish confidence limits for those means, and measure propagation-induced noise variability. Even for identical nominal cruise conditions, peak sound levels for individual overflights varied substantially about the average, particularly when overflights were performed on different days. Large day-to-day variations in peak level measurements appeared to be caused by large day-to-day differences in propagation conditions and tended to obscure small variations arising from operating conditions. A parametric evaluation of the sensitivity of this prediction method to weather measurement and source level uncertainties was also performed. In general, predictions showed good agreement with measurements. However, the method was unable to predict short-term variability of ensemble-averaged data within individual overflights. Although variations in absorption appear to be the dominant factor in variations of peak sound levels recorded on the ground, accurate predictions of those levels require that a complete description of operational conditions be taken into account. The comprehensive and integrated methods presented in this paper have adequately predicted ground-measured sound levels. On average, peak sound levels were predicted within 3 dB for each of the three different cruise conditions. Garber, Donald P. and Willshire, William L., Jr. Langley Research Center RTOP 535-03-11-02...
Annoyance Caused by Aircraft en Route Noise
Author: David A. McCurdyPublisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 44
Book Description
FAA/NASA En Route Noise Symposium
Author: Monthly Catalog of United States Government Publications
Author: Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1450
Book Description
NASA Technical Memorandum
Author: Scientific and Technical Aerospace Reports
Author: Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 700
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Monthly Catalogue, United States Public Documents
Author: Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1484
Book Description
In-flight Near- and Far-field Acoustic Data Measured on the Propfan Test Assessment (PTA) Testbed and with an Adjacent Aircraft
Author: Richard P. WoodwardPublisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 161
Book Description
Author: