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Showing papers on "Aircraft noise published in 1972"


01 Mar 1972
TL;DR: In this paper, a combined aerodynamics, acoustics and bionics study was conducted in an attempt to discover novel mechanisms to reduce the noise associated with aircraft flight, including vortex sheet generators, compliant surfaces, and distributed wing porosity.
Abstract: : A combined aerodynamics, acoustics and bionics study was conducted in an attempt to discover novel mechanisms to reduce the noise associated with aircraft flight. The strigiformes order of birds, selected in the bionics effort as possessing characteristics of silent flight, was studied extensively. Three mechanisms producing the potential for acoustic quieting were discovered as a result of this study. These are: vortex sheet generators, compliant surfaces, and distributed wing porosity. An experimental program aimed at initiating full scale flight evaluation of these concepts was outlined. The detailed results of these studies are included. The report develops design concepts which may be applied to obtain ultra quiet flight for convert/reconnaissance/surveillance aircraft such as the YO-3.

78 citations


Journal ArticleDOI
TL;DR: In this article, the authors present an investigation on annoyance due to aircraft noise exposure and demonstrate that the extent of annoyance reactions in an exposed population is closely correlated to the noise level of single overflights.

74 citations


01 Aug 1972
TL;DR: In this paper, the results of a study of community reaction to jet aircraft noise in the vicinity of airports in Chattanooga, Tennessee and Reno, Nevada were presented. But the study was conducted in less highly urbanized areas.
Abstract: The results are presented of a study of community reaction to jet aircraft noise in the vicinity of airports in Chattanooga, Tennessee, and Reno, Nevada. These cities were surveyed in order to obtain data for comparison with that obtained in larger cities during a previous study. (The cities studied earlier were Boston, Chicago, Dallas, Denver, Los Angeles, Miami, and New York.) The purpose of the present effort was to observe the relative reaction under conditions of lower noise exposure and in less highly urbanized areas, and to test the previously developed predictive equation for annoyance under such circumstances. In Chattanooga and Reno a total of 1960 personal interviews based upon questionnaires were obtained. Aircraft noise measurements were made concurrently and aircraft operations logs were maintained for several weeks in each city to permit computation of noise exposures. The survey respondents were chosen randomly from various exposure zones.

23 citations


01 Nov 1972
TL;DR: A theoretical model for the generation of blade-passage noise caused by the interaction of rotor wakes with the downstream stator blades in a fan stage has been compiled and a set of significant parameters has been identified to reduce this interaction-caused blade-Passage frequency noise.
Abstract: A theoretical model for the generation of blade-passage noise caused by the interaction of rotor wakes with the downstream stator blades in a fan stage has been compiled. This model has combined a description of the rotor wake based on existing experimental correlations with an existing theory for the response of the stator blades to those wakes. This model of the interaction-caused blade-passage noise has been used to examine some effects of blade geometry and flow conditions on the noise generated. A set of significant parameters has been identified to reduce this interaction-caused blade-passage frequency noise. A redesign of an existing fan with the use of these concepts has produced a theoretical noise reduction of more than 7 decibels.

21 citations


01 May 1972
TL;DR: In this article, the authors present a consistent set of prediction methods which may be used to estimate near field noise levels for jet powered and rotor/propeller powered VTOL aircraft operating in close proximity to the ground.
Abstract: : This report establishes a consistent set of prediction methods which may be used to estimate near field noise levels for jet powered and rotor/propeller powered VTOL aircraft operating in close proximity to the ground. The methods provided utilize available theory augmented extensively by experimental data which was available or was obtained during the program. The noise prediction methods presented will allow an analysis of near field environments of VTOL aircraft using a simplified procedure suitable for manual calculations. The experimental effort carried out in the program consisted of noise measurements in the near field of a model propeller and a subsonic jet in a free and vertical configuration. Ground reflection correction factors for a simple source are tabulated along with the computer program listing. The methods described in this report are intended for use by aircraft designers for the prediction of the near field noise environment of VTOL aircraft as required in MIL A 8893 Airplane Strength and Rigidity, Sonic Fatigue Resistance.

13 citations


Journal ArticleDOI
TL;DR: The model to estimate the cost of aircraft noise devised for the Roskill Commission on the Third London Airport is explained and discussed and problems in arriving at values to use in the model are discussed.
Abstract: The model to estimate the cost of aircraft noise devised for the Roskill Commission on the Third London Airport is explained and discussed. The treatment used by the commission for different activities affected by noise was based on the principle of trying to forecast how the activity in question would react to the impact of noise. A first step in the costing noise nuisance model is to determine the smallest amount the government would have to pay to each householder to willingly accept the noise nuisance. Details of the model operation are discussed and illustrated by a diagram. Problems in arriving at values to use in the model are discussed. Residential noise costs for Nuthampstead (72 million pounds sterling) and the three other sites are discussed. These noise costs are important in distinguishing between alternative London Airport sites.

11 citations


01 Apr 1972
TL;DR: In this article, the procedures for selecting engines for transport and combat aircraft during the design process are presented, and the aerodynamic characteristics of supercritical wings and their effect on engine selection are reported.
Abstract: The procedures for selecting engines for transport and combat aircraft during the design process are presented. The types of aircraft considered are: (1) a long haul conventional takeoff and landing transport, (2) a short haul vertical takeoff and landing transport, (3) a long range supersonic transport, and (4) a fighter aircraft. The influence of aircraft noise considerations on engine selection is examined. The aerodynamic characteristics of supercritical wings and their effect on engine selection are reported.

9 citations


Journal ArticleDOI
TL;DR: In this article, the authors take the advantages of aviation for granted and explain that it is technically feasible to build a subsonic aircraft and engine combination quiet enough not to annoy the public.
Abstract: Everyone agrees that the noise from aircraft has become an unreasonable nuisance to people living around airports. Because of it aviation is now extremely unpopular in some quarters and there is energetic public resistance both to the extension of existing airports and to the creation of new ones. The restriction on night take-off of jet aircraft from London airport is another illustration of the problem. This public attitude is understandable and it is tending to obscure the fact that transport aviation has made a great contribution to improving the quality of life. Taking one small example, without aviation the package tour holiday, which represents good value for money, would hardly be possible. The purpose of this paper is to take the advantages of aviation for granted and to explain that it is technically feasible to build a subsonic aircraft and engine combination quiet enough not to annoy the public.

7 citations


01 Nov 1972
TL;DR: In this paper, the authors present a tool for the local planner, local government and others in developing a comprehensive aircraft noise abatement policy and program, including a discussion of the entire process of developing a noise-abatement program including defining the existing noise situation, determining where this noise situation may conflict with existing or proposed development, developing a program for reducing conflicts, evaluating impact of the program on the community, implementing the program through legislation and action programs.
Abstract: This manual interprets the information developed in the Metropolitan Aircraft Noise Abatement Policy Studies reports and other case studies of aircraft noise abatement and presents it in a form that provides a practical tool for the local planner, local government and others in developing a comprehensive aircraft noise abatement policy and program. The manual contains a discussion of the entire process of developing a noise abatement program including (1) defining the existing noise situation, (2) determining where this noise situation may conflict with existing or proposed development, (3) developing a program for reducing conflicts, (4) evaluating impact of the program on the community, (5) implementing the program through legislation and action programs. Technical appendices include aircraft EPNL contours, method of finding Noise Exposure Forecast (NEF) level for a given location, analysis of sound insulation, and annotated bibliography.

6 citations


Proceedings ArticleDOI
01 Aug 1972
TL;DR: In this paper, the authors describe the results of a Lockheed parametric analysis of the performance, environmental factors, and economics of an advanced commercial transport envisioned for operation in the post-1985 time period.
Abstract: This paper describes the results of a Lockheed parametric analysis of the performance, environmental factors, and economics of an advanced commercial transport envisioned for operation in the post-1985 time period The design parameters investigated include cruise speeds from Mach 085 to Mach 10, passenger capacities from 200 to 500, ranges of 2800 to 5500 nautical miles, and noise level criteria NASA high performance configurations and alternate configurations are operated over domestic and international route structures Indirect and direct costs and return on investment are determined for approximately 40 candidate aircraft configurations The candidate configurations are input to an aircraft sizing and performance program which includes a subroutine for noise criteria Comparisons are made between preferred configurations on the basis of maximum return on investment as a function of payload, range, and design cruise speed

6 citations


01 Jan 1972
TL;DR: The results of a social survey designed to investigate the influence of background (road traffic) noise on annoyance due to aircraft noise, and on general dissatisfaction with the total noise environment are presented.
Abstract: The results of a social survey designed to investigate the influence of background (road traffic) noise on annoyance due to aircraft noise, and on general dissatisfaction with the total noise environment are presented. Nine sites with 3 aircraft and 3 traffic conditions were selected and 35 people per site interviewed. The regression lines for site mean aircraft annoyance scores (Guttman Scale) for each traffic condition show that the same annoyance score is achieved at an aircraft exposure 10 NNI lower, when traffic is reduced from heavy to access only. The general noise dissatisfaction shows an increase with traffic at low NNI, but a decrease at high NNI. The use of the noise pollution level unit satisfactorily explains this result, increasing the correlation coefficient for the grouped data from 0.94 against NNI to 0.96. (Author)

Journal ArticleDOI
TL;DR: In this paper, the authors examined the impact on aircraft noise requirements of a change in emphasis, from vehicle economy to noise acceptability, and used existing literature to estimate the maximum noise exposure from aircraft that a community would probably find acceptable.

01 Jun 1972
TL;DR: In this article, audiograms and other data related to ear conditions and noise exposure were obtained from residents drawn from two neighborhoods in the greater Los Angeles area, one community bordered Los Angeles International Airport and had been subjected over the years to frequent takeoff noise of high level.
Abstract: : Audiograms and other data related to ear conditions and noise exposure were obtained from residents drawn from two neighborhoods in the greater Los Angeles area. One community bordered Los Angeles International Airport and had been subjected over the years to frequent takeoff noise of high level. Maximum rms measurements of these aircraft sounds outdoors in this neighborhood ranged from 76 to 101 dBA with a median of 88 dBA. The second community was similar to the airport one in demography but free of significant aircraft noise intrusion. Noise levels here rarely exceeded 60 dBA and commonly were 50 dBA or less. Both groups displayed average hearing levels as good and at certain frequencies slightly better than estimates obtained from the National Health Survey of 1960-1962. The overall findings did not make it possible to draw firm conclusions about community aircraft noise exposure as a cause of the apparent differences in hearing levels between the two groups.

Journal ArticleDOI
TL;DR: In this paper, a criterion for reverberation in a city street due to an aircraft is developed in terms of images formed, indicating the amplification or shielding of noise from low flying aircraft.
Abstract: Experimental studies of sound propagation from a source situated above roof top level in an urban environment have indicated the amplification and shielding effect of buildings. These experiments have been supplemented by diagnostic tests with a spark source which indicate the paths of propagation and their contribution to the received sound. A criterion for reverberation in a city street due to an aircraft is developed in terms of images formed. Charts indicating the amplification or shielding of noise from low flying aircraft are presented.

01 Jul 1972
TL;DR: In this paper, two series of psychoacoustic judgment tests were conducted to determine the applicability of the psychophysical Theory of Signal Detectability (TSD) to prediction of the aural detectability of light aircraft noise signatures in jungle noise backgrounds.
Abstract: : Laboratory experiments were undertaken to develop improved aural detection criteria for light aircraft. Specifically two series of psychoacoustic judgment tests were conducted to determine the applicability of the psychophysical Theory of Signal Detectability (TSD) to prediction of the aural detectability of light aircraft noise signatures in jungle noise backgrounds. The first series of tests produced data supporting development of a simplified graphical prediction method based on TSD. The second testing program validated the precision and accuracy of the prediction method under quasi-realistic listening conditions. Predicted levels of performance were typically within one or two dB of the data averaged for all observers.

01 Jan 1972
TL;DR: In this article, the sociometric studies considered show that fear of crash is the strongest single variable for aircraft noise exposure and the annoyance produced by it, which is the same as the fear of being involved in a crash.
Abstract: Organized community resistance to any plan of airport development has become so intense that noise exposure is a primary consideration in plans for new airports, runway extensions, and the introduction of new types of aircraft. Approaches for evaluating the amount of aircraft noise and the annoyance produced by it are discussed. The sociometric studies considered show that fear of crash is the strongest single variable.

Journal ArticleDOI
01 Jul 1972

01 Aug 1972
TL;DR: In this paper, the effect of fundamental design choices on noise levels is analysed and the principal noise sources, and therefore the optimum noise control measures, are a function of disc loading, and it is found that increase in rotor scale gives a substantial benefit in subjective levels at the lower disc loadings.
Abstract: This paper presents a detailed evaluation of design factors affecting noise annoyance by V/STOL aircraft. Community noise annoyance is quantified on the basis of recent analyses of survey data, and the implications on V/STOL design discussed. The effect of fundamental design choices on noise levels is analysed. The principal noise sources, and therefore the optimum noise control measures, are a function of disc loading. It is found that increase in rotor scale gives a substantial benefit in subjective levels at the lower disc loadings. Rotor noise source mechanisms are discussed in detail and the dominant effect of the unsteady aerodynamic input to the rotor demonstrated. Data on the effects of recirculation on noise is presented. Two approaches for low noise V/STOL seem to be feasible. These are the low disc loading open rotor, and a ducted fan with substantial duct attenuation treatment. The principal noise control methods for each approach are given.

01 Aug 1972
TL;DR: In this paper, a progress report on the problem of community noise control for jet-powered STOL aircraft is presented, along with noise control approaches for meeting these goals, such significant noise control factors as the basic engine cycle, engine-airframe integration varieties, and certain details of the lift augmentation system.
Abstract: Progress report on the problem of community noise control for jet-powered STOL aircraft. Noise goals are discussed, along with noise control approaches for meeting these goals. Such significant noise control factors as the basic engine cycle, engine-airframe integration varieties, and certain details of the lift augmentation system are given special attention.


01 May 1972
TL;DR: This program was undertaken to develop, through analysis, design, experimental static testing, wind tunnel testing, and design integration studies, an augmentor wing jet flap configuration for a jet STOL transport aircraft having maximum propulsion and aerodynamic performance with minimum noise generation.
Abstract: This program was undertaken to develop, through analysis, design, experimental static testing, wind tunnel testing, and design integration studies, an augmentor wing jet flap configuration for a jet STOL transport aircraft having maximum propulsion and aerodynamic performance with minimum noise generation. The program had three basic elements: (1) static testing of a scale wing section to demonstrate augmentor performance and noise characteristics; (2) two-dimensional wind tunnel testing to determine flight speed effects on performance; and (3) system design and evaluation which integrated the augmentor information obtained into a complete system and ensured that the design was compatible with the requirements for a large STOL transport having a 500-ft sideline noise of 95 PNdB or less. This objective has been achieved.

01 Jan 1972
TL;DR: In this article, a three-step program to evaluate public acceptance of short takeoff aircraft noise was conducted, and the three steps were: (1) definition of short aircraft noise characteristics, (2) laboratory tests to evaluate individual responses, and (3) the use of community survey data to extrapolate conventional takeoff aircraft experience.
Abstract: The responses of people to special noise characteristics associated with short takeoff aircraft are discussed. The findings of studies which have yielded data that may be pertinent to community acceptance of short takeoff aircraft noise are presented. A three step program to evaluate public acceptance of short takeoff aircraft noise was conducted. The three steps were: (1) definition of short takeoff aircraft noise characteristics, (2) laboratory tests to evaluate individual responses, and (3) the use of community survey data to extrapolate conventional takeoff aircraft experience.

01 Jul 1972
TL;DR: In this article, the results of analysis directed towards determining Microwave Landing System (MLS) signal requirements for conventional aircraft are discussed, and the requirements for a reevaluation of the MLS as sole primary landing aid are presented.
Abstract: The results of analysis directed towards determining Microwave Landing System (MLS) signal requirements for conventional aircraft are discussed. The phases of flight considered include straight-in final approach, flareout, and rollout. A limited number of detailed problems in performance analysis are studied. Data from computer simulation, covariance propagation and system optimization, with a careful selection of variables provides a means for generalizing from the results of specific experiments to more comprehensive functional, data rate, beam noise, and I control system requirements for automatic landing in turbulence. Conclusions point toward the requirements for a re-evaluation of the MLS as sole primary landing aid; the problem arises during flareout in turbulence, when elevation information is inadequate to maintain precise sink rate control. Minimum suitable data rate and maximum allowable noise for final approach are also recommended.

ReportDOI
01 Sep 1972
TL;DR: The Phase 2 Quiet Helicopter Program (P2QP) as mentioned in this paper used a Hughes OH-6A Light Observation Helicopter to obtain a maximum of quieting, which required a balanced treatment of each noise-producing source throughout the full frequency range.
Abstract: : The report presents the results of the Phase 2 Quiet Helicopter Program. A Hughes OH-6A Light Observation Helicopter was extensively modified to obtain a maximum of quieting. The purpose was to apply the latest known sound-suppression techniques available to industry to an actual helicopter and then to measure the results. An acoustic goal was set which required a balanced treatment of each noise-producing source throughout the full frequency range. Noise reductions ranged from 14 to 20 db depending on the flight conditions. The report describes the detailed configuration changes, the test and development programs, and the final sound level measurements compared to the standard OH-6A.


01 Jan 1972
TL;DR: The present status of the Quiet Engine Program is reviewed and the future prospects suggested by recent quiet engine test results are discussed in this article, and the minimization of the economic penalty associated with this noise reduction technology is studied.
Abstract: The present status of the Quiet Engine Program is reviewed, and the future prospects suggested by recent quiet engine test results are discussed. Following a brief survey of noise sources, quiet engine design features, and the major elements of the Quiet Engine Program, a review is presented of specific quiet engine test that includes the two baseline quiet engines tested and flyover noise comparison results. It is shown that the application to future aircraft of the developed and demonstrated engine noise reduction technology can bring about a substantial reduction in aircraft noise levels. The minimization of the economic penalty associated with this noise reduction technology is being studied.

01 Jun 1972
TL;DR: In this article, the authors describe the present legal measures in Great Britain against noise, the legal powers of local planning authorities to control noise, and the principles of physical planning against noise.
Abstract: This article describes the present legal measures in Great Britain against noise, the legal powers of local planning authorities to control noise, and the principles of physical planning against noise. The maximum permitted sound levels in urban and rural areas are mentioned together with their effect on airports, aircraft, traffic and traffic management methods of insulating buildings and houses, and their effectiveness in noise reduction are tabulated. /TRRL/

01 Mar 1972
TL;DR: In this article, the authors described the concepts which underlie the detection of aircraft by the human ear and delineated a scheme for predicting the range at which a given aircraft will first be heard by an average listener; this scheme is also applicable to comparing the aural detectabilities of alternate aircraft configurations and to identifying those components of the noise of a given configuration which bear prime responsibility for the aircraft's detectability.
Abstract: : The concepts which underlie the detection of aircraft by the human ear are described. A scheme is delineated for predicting the range at which a given aircraft will first be heard by an average listener; this scheme is also applicable to comparing the aural detectabilities of alternate aircraft configurations and to identifying those components of the noise of a given configuration which bear prime responsibility for the aircraft's detectability. Means are presented for predicting the noise due to all sources likely to be significant for light aircraft, the attenuation of acoustic signals propagating from an aircraft to a listener on the ground, and the ability of a listener to detect an acoustic signal in the presence of background noise. From a diffuse literature of acoustics, engineering mechanics and aeronautical engineering this report gathers knowledge and data on methods of predicting the source intensities, propagation and aural detection os sound radiated by military aircraft of the utility class. This report will be used for the design of quiet aircraft and discloses detailed methods used in evaluating such aircraft from the acoustical standpoint.


Journal Article
TL;DR: In this article, the authors discuss the present crisis facing the aviation industry and discuss the need for new air carrier airports to meet the forecasted increase in demand by 1980, while the public's increasing concern with the environment and with the quieting of life has brought about increasing resistance to aircraft generations The author suggests that for many years the legal issue which prevailed was not the level of air craft noise but rather the applicability of aircraft flight to common law which stated that he who owns the land owns it to the end of the universe.
Abstract: This article discusses the present crisis facing the aviation industry The author states that the expansion of air commerce is essential in orders to provide society with economic gains and cultural benefits By 1980, it is expected that sixty-two new air carrier airports will be required to meet the forecasted increase in demand However, aircraft noise, coupled with the public's increasing concern with the environment and with the quieting of life has brought about increasing resistance to aircraft generations The author suggests that for many years the legal issue which prevailed was not the level of air craft noise but rather the applicability of aircraft flight to common law which stated that he who owns the land owns it to the end of the universe Although the Supreme Court repected that rule, it did hold that landowners own at least as much of the space above the ground as he can occupy or use in connection with the land The second important legal issue was where monetary liability was to be placed assuring that flights over private property were so low and so frequent as to be a direct and immediate interference with the enjoyment and use of the land The question of liability was settled bythe Supreme Court in Griggs v Allegheny County The Court held that the airport operator was liable for whatever air easements are necessary for aircraft to use in the course of landing at and taking off from its runways It remains to be seen how the courts will interpret the Supreme Court's decision in Griggs in view of the reasonalbe balance required between communities affected by aircraft noise and aircraft site selection, and the continuing need for new air carrier airports to meet the expected growth of aviation