Download or read book En Route Noise Levels from Propfan Test Assessment Airplane written by Donald P. Garber and published by . This book was released on 1994 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book En Route Noise Levels from Propfan Test Assessment Airplane written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-02 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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...

Download or read book Annoyance Caused by Aircraft en Route Noise written by David A. McCurdy and published by . This book was released on 1992 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book In flight Near and Far field Acoustic Data Measured on the Propfan Test Assessment PTA Testbed and with an Adjacent Aircraft written by Richard P. Woodward and published by . This book was released on 1993 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book FAA NASA En Route Noise Symposium written by and published by . This book was released on 1990 with total page 884 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structure Borne Noise Estimates for the PTA Aircraft written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-16 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Estimates of the level of in-flight structure-borne noise transmission in the Propfan Test Assessment Aircraft were carried out for the first three blade passage frequencies. The procedure used combined the frequency response functions of wing strain to cabin sound pressure level (SPL) response obtained during ground test with in-flight measured wing strain response data. The estimated cabin average in-flight structure-borne noise levels varied from 64 to 84 dB, with an average level of 74 dB. The estimates showed little dependence on engine/propeller power, flight altitude, or flight Mach number. In general, the bare cabin noise levels decreased with increasing propeller tone, giving rise to a plausible structure-borne noise transmission problem at the higher blade passage tones. Without knowledge of the effects of a high insertion loss side wall treatment on structure-borne noise transmission, no quantitative conclusions could be made. Unruh, James F. Unspecified Center...

Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1995 with total page 1636 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Technical Paper written by and published by . This book was released on 1991 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Technical Paper written by United States. National Aeronautics and Space Administration and published by . This book was released on 1992 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Conference Publication written by and published by . This book was released on 1990 with total page 876 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proposed Master Plan Update Development Actions Seattle Tacoma Sea Tac International Airport King County written by and published by . This book was released on 1996 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on with total page 1450 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Annual Report written by Lewis Research Center and published by . This book was released on with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Annual Report 1989 written by Lewis Research Center and published by . This book was released on 1989 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Technical Paper written by and published by . This book was released on 1979 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: