Author: J. J. CatherinesPublisher:
ISBN:
Category :
Languages : en
Pages : 30
Book Description
Interior Noise Levels of Two Propeller-driven Light Aircraft
Author: J. J. CatherinesPrediction of Light Aircraft Interior Noise
Author: James T. HowlettPublisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 48
Book Description
Sources and Characteristics of Interior Noise in General Aviation Aircraft
Author: John J. CatherinesPublisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 44
Book Description
Noise Levels and Data Analyses for Small Prop-Driven Aircraft
Author: J. Steven NewmanPublisher:
ISBN:
Category :
Languages : en
Pages : 193
Book Description
During the Summer and Fall of 1982, the FAA Office of Environment and Energy, Noise Abatement Division, conducted a noise measurement program to evaluate proposed revisions of International and U.S. noise certification standards for light-weight propeller-driven aircraft. Tests were conducted using both single- and twin-engine propeller-driven light aircraft. Normally aspirated, turbo-charged, and turboprop engines were included, as were both fixed and variable pitch propellers. Takeoff noise measurements were made for eighteen aircraft. Additional measurements for nine of these aircraft (during level flight) provided sufficient data to examine the relationship of noise level versus helical tip Mach Number and engine power setting. This report presents noise measurements, aircraft position data, meteorological data, and cockpit instrument readings acquired during the test. Data analyses include: corrections to proposed noise certification reference conditions, development of Mach Number and Power Correction functions, empirical examination of sound propagation, regression of noise level versus weight (and the logarithm of weight) and correlation of acoustical intensity (AL) and acoustical dose (SEL) noise metrics. While this report concludes that a takeoff noise certification procedure is feasible and will provide consistent results for a given aircraft, it remains uncertain whether or not equal stringency (or even comparable stringency) can be achieved between the existing certification procedure and the proposed takeoff procedure.
Analytical Study of Interior Noise Control by Fuselage Design Techniques on High-speed, Propeller-driven Aircraft
Author: NASA Technical Paper
Author: United States. National Aeronautics and Space AdministrationPublisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 802
Book Description
General Aviation Interior Noise
Author: NASA Technical Paper
Author: Measured Or Estimated (uncertificated) Airplane Noise Levels
Author: United States. Federal Aviation AdministrationPublisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 44
Book Description
Potential Subjective Effectiveness of Active Interior Noise Control in Propeller Airplanes
Author: Clemans A. PowellPublisher:
ISBN:
Category : Acoustical engineering
Languages : en
Pages : 40
Book Description
Active noise control technology offers the potential for weight-efficient interior noise reduction, particularly for propeller aircraft. However, there is little information on how passengers respond to this type of interior noise control. This paper presents results of two experiments that use sound quality engineering practices to determine the subjective effectiveness of hypothetical active noise control (ANC) systems in a range of propeller aircraft. The two experiments differed by the type of judgments made by the subjects: pair comparisons based on preference in the first and numerical category scaling of noisiness in the second. Although the results of the two experiments were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference. The reductions in subjective response due to the ANC conditions were predicted with reasonable accuracy by reductions in measured loudness level. Inclusion of corrections for the sound quality characteristics of tonality and fluctuation strength in multiple regression models improved the prediction of the ANC effects.