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1974-02-01
Technical Paper
740455
Jeffrey V. Bowles, Thomas L. Galloway, Mark H. Waters
Propulsion system sizing for mechanical flap and externally blown flap aircraft is demonstrated. Included in this study is the effect of various levels of noise suppression on the aircraft final design characteristics. Both aircraft are sized to operate from a 3000 ft runway and perform the same mission. For each aircraft concept, propulsion system sizing is demonstrated for two different engine cycles-one having a fan pressure ratio of 1.5 and a bypass ratio of 9 and the other having a fan pressure ratio of 1.25 and a bypass ratio of 17.8. The results presented include the required thrust to weight ratio, wing loading, resulting gross weight and direct operating costs as functions of the engine noise level for each combination of engine cycle and aircraft concept.
1974-02-01
Technical Paper
740458
F. Klujber, J. V. O'Keefe
Recent developments in sonic inlet technology are presented with particular emphasis on STOL propulsion systems. Inlet noise reduction requirements are discussed for an augmentor wing and an upper surface blowing type of propulsion system. The current state of the art is discussed with respect to performance and noise potential of different sonic inlet concepts. Acoustic and aerodynamic performance comparison is presented for several inlet configurations based on experimental results.
1974-02-01
Technical Paper
740502
H. R. Leslie, J. A. Bennett
It is hypothesized that the potential value of powered lift may be greater for transport applications requiring RTOL and CTOL field lengths than for those requiring STOL performance. Thus, it is implied that powered lift can be applied effectively to aircraft designed for medium and long haul, as well as short haul. This premise has been reached on the basis of observed trends in direct operating cost, mission fuel consumption, and, most significantly, community noise footprint areas for both powered lift and conventional mechanical flap configurations. Some pertinent results from recent NASA-sponsored configuration design and system studies for quiet short haul and fuel-conservative aircraft are discussed, and further data are developed to explore the potential value of incorporating powered lift concepts in advanced aircraft designs for medium and long haul applications.
1974-02-01
Technical Paper
740359
W. B. Harlamert
An aircraft propeller with five blades has been developed for application on relatively high horsepower turbine engines. This propeller is capable of absorbing high horsepower at low engine rpm to effect a low propeller noise emission. Propeller performance remains satisfactory, as its design is intended for a commuter type aircraft. Structurally, the addition of a blade has not created serious design problems. For its intended application, the five-blade best satisfies the requirement for a “quiet” propeller. It is doubtful if the addition of more blades would be desirable.
1974-02-01
Technical Paper
740361
Edmund W. Sellman
The objective of this report is to outline the development of noise standards applicable to light, propeller-driven aircraft. The new noise abatement standards required under the Noise Control Act of 1972 are discussed in regard to their impact on future aircraft designs and their economic effect on the general aviation industry. Since no type certification requirements for noise abatement currently existed for propeller-driven aircraft (other than for those in the transport category), it was necessary to set up a testing procedure to determine how the standards could be modified for such aircraft. Discussed in detail are the noise evaluation measures, testing procedures, and maximum noise level standards.
1974-02-01
Technical Paper
740360
Narayanan Ganesan
From the standpoint of marketing as well as safety, control of aircraft interior noise is of considerable interest to the manufacturers of business aircraft. The interior acoustics engineer in the industry, having no fund of accumulated experience or research to draw from in the industry itself, has to piece together a working design procedure from a knowledge of boundary-layer theory, jet noise, random vibrations, and architectural acoustics to meet an acceptable cabin noise criterion for the small aircraft. In this paper, methods are outlined to calculate the cabin noise levels due to the three main noise sources-the boundary-layer pressure fluctuations, jet exhaust, and internal equipment. Formulas for quick estimation of overall noise levels due to these sources as well as methods to obtain octave band levels are given. The paper also discusses manufacture or service-related noises and methods for identifying their sources.
1974-02-01
Technical Paper
740362
Thomas L. Galloway
Abstract The potential for reducing the noise footprint area of general aviation aircraft through propeller and engine modifications while maintaining good aircraft performance is investigated. The analysis considers propeller changes on representative single and twin engine designs and the use of geared engines on the twin design. A reduced diameter, four-bladed propeller was attractive for both designs, and the potential exists for reducing footprint area by an order of magnitude for the geared engine twin.
1974-02-01
Technical Paper
740846
William M. Owen, Jerry S. Todd
The Solar Division of International Harvester Co. has designed, fabricated, and tested a sound-attenuated enclosure for the standard 10 kw turboalternator generator set previously developed by Solar. The enclosure was designed to achieve essentially silent power performance by being inaudible at a distance of 100 m under extremely quiet backgrounds.
1974-02-01
Technical Paper
740815
Clark J. Beck
Recent experience with vibration qualification of avionics for the B-1 airplane has revealed deficiencies in commonly used vibration design and test procedures. Specific examples of deficiencies are discussed. Recommendations for improving vibration design and test procedures are presented in the areas of environment prediction, qualification testing, and use of vibration isolators. Suggestions are made relative to vibration design and testing in light of the “try-before-buy” concept.
1974-02-01
Technical Paper
741132
Ralph C. Raabe, Ioan Burche
Noise tests were conducted on new and retreaded truck tires of a wide variety of patterns using three different procedures. Single tires on the test wheel and 2-tire sets on the road were correlated with the standard 4-tire sets in accordance with the Recommended Practice SAE J57 Procedure. The correlation was analyzed and the conversion techniques were discussed with the conclusions that it is possible to convert test wheel data to equivalent road test data. The results show that retreaded truck tires are not noisier than new tires of similar construction and tread design.
1974-02-01
Technical Paper
740001
Richard L. Staadt
This paper discusses the basics of heavy diesel truck exterior-noise analysis and reduction. Subjects addressed are noise and its measurement, truck component noise sources and their contribution to overall noise level, analysis methods, and steps required to reduce noise levels. Data from a truck noise analysis and reduction program is presented to illustrate the application of noise control principles.
1974-02-01
Technical Paper
740609
William F. Reiter, Allen C. Eberhardt
This paper describes the procedure and instrumentation used to telemeter, record, and analyze in-service truck tire accelerations. The tire sound signal monitored at a point approximately 1 ft to the rear of the tire was recorded simultaneously with the acceleration signal on board the test vehicle. Subsequent time domain, frequency domain, and level analyses of the signals show the importance and relationship of tire acceleration to the tire noise generated. The results reported are for a 10:00-20 cross-bar type tire with three states of wear, two load conditions, and three speeds.
1974-02-01
Technical Paper
740713
S. W. Coates, G. P. Blair
This paper describes a theoretical and experimental investigation of the noise characteristics of some basic internal combustion engine exhaust systems. On the basis of a one-dimensional analysis of the unsteady internal flow, the treatment is extended to consider the noise radiated by the efflux of gas from the atmospheric termination of the tail pipe. Using a rotary valve exhaust simulator, experimental pressure-time histories and one-third octave noise spectrograms were obtained. These are compared with those calculated.
1973-11-01
Standard
J192A_197311
This SAE Recommended Practice establishes the instrumentation, test site, and test procedure for determining the maximum exterior sound level for snowmobiles. Sound propagation is directly related to the ground cover and provides the largest variation to the measured result. A correction factor is introduced to improve year round test repeatability of the results on grass surfaces by correcting their spectrum to be similar to snow covered spectra. Measured sound pressure levels are also highly dependent on the degree of track slip present when performing the vehicle acceleration. Operators should attempt to limit track slip as much as possible while maintaining the requirements described in 5.1.1.
1973-11-01
Standard
J903C_197311
This SAE Recommend Practice establishes for passenger cars, light trucks, and multipurpose vehicles with GVW or 4500 kg (10 000 lb) or less: a. Minimum performance standards for windshield wiper systems. b. Test procedures that can be conducted on uniform test equipment by commercially available laboratory facilities. c. Uniform terminology of windshield wiper system characteristics and phenomena consistent with those found in guides for the use of engineering layout studies to evaluate system performance. d. Guides for the design and location of components of the systems for function, servicing of the system, etc. The test procedures and minimum performance standards, outlined in this document, are based on currently available engineering data. It is the intent that all portions of the document will be periodically reviewed and revised as additional data regarding windshield wiping system performance are developed.
1973-07-01
Standard
J336A_197307
This SAE Recommended Practice describes the equipment and procedure for determining the truck cab interior sound level over the upper half of the engine speed range. This practice applies to motor trucks and truck-tractors and does not include construction and industrial machinery.
1973-06-01
Standard
J577_197306
This SAE Recommended Practice provides procedures, and information to conduct vibration (impact) tests on lighting devices and their components as well as other safety equipment used on vehicles.
1973-04-15
Standard
ARP731A
The purpose of this SAE Aerospace Recommended Practice (ARP) is to establish recommendations for the design, installation and testing of air vehicle vapor cycle refrigeration systems. These recommendations are representative of the refrigerant cycles.
1973-04-01
Standard
J34_197304
This SAE Recommended Practice establishes the procedure for measuring the maximum exterior sound level of recreational motorboats while being operated under a variety of operating conditions. It is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances.
1973-04-01
Standard
J366B_197304
This SAE Standard establishes the test procedure, environment, and instrumentation for determining the maximum exterior sound level for highway motor trucks, truck tractors, and buses. The test results obtained by this test procedure give an objective measure of the maximum noise level emitted by vehicles under a prescribed condition. A subjective rating of the annoyance caused by vehicles in use may not be directly related to this type of noise level measurement.
1973-02-01
Technical Paper
730102
Robert H. Badgley, Neville F. Rieger
Influence coefficient balancing of an advanced gas turbine rotor in fluid-film bearings with nonsymmetrical properties has been examined. The effect of the number of balancing planes in use of the quality of balance has been studied with particular attention being paid to the reasons why an increase from three planes to four planes gives no apparent improvement. Effects examined include the influence of nonsymmetrical bearing properties, the effect of having a bending critical speed close to either side of the intended operating speed, and the effect of correction weight errors on balance quality. Reasons why the addition of a fifth balancing plane resulted in a significant improvement in balance quality are given.
1973-02-01
Technical Paper
730133
Robert M. Storwick, David C. Schlick
Noise produced by automotive ignition systems can deteriorate the performance of nearby communication systems. An important step toward alleviating this difficulty is to characterize the ignition noise. Measurements have been made of the noise peak amplitude distribution of a number of identically equipped vehicles over a fixed period of time. Both vertical and horizontal polarizations were used, and measurements were made at two frequencies, 145 and 230 MHz. These statistics were then compared to various probability distributions to attempt to characterize the amplitude distribution of the noise. The distributions studied were: the log-normal, the exponential, the Rayleigh, and the Weibull distributions. It was concluded that the best fit was provided by the Weibull distribution. The parameters of the best fitting distribution are primarily a function of the antenna's polarization, with frequency having only a minor effect.
1973-02-01
Technical Paper
730160
G. P. Blair, S. W. Coates
From a theoretical analysis of the unsteady efflux from the open end of a simulated reciprocating internal combustion engine exhaust system a prediction of overall and one-third octave sound pressure levels in space, due to this gas flow, is produced. The predictions are compared with measured levels and show a high degree of correlation.
1973-02-01
Technical Paper
730056
C. K. H. Dharan, D. W. Windstein
This paper presents a systematic method for obtaining an acceptable mounting system for engine accessories in a short length of time with minimum redesign of metal components. A mathematical model is used to determine the various resonance conditions. Electronic instrumentation is used to verify the behavior of the system and determine amplitudes of vibration. Finally the endurance testing conducted to confirm analytical and experimental results is discussed.
1973-02-01
Technical Paper
730085
G. M. Cornetti, V. Arrigoni, F. Sezzi, G. F. Zanoni
The detection of cyclic dispersion, knocking, preignition, misfiring and other phenomena related with abnormal combustion in spark ignition engines has been extensively studied in the past. The transducers most commonly used detect pressure and/or ionization in the combustion chamber. By employing transducers that detect engine head movement it has been possible to examine these phenomena without particular engine modifications, thus enabling measurements to be made in commercial cars. These transducers are used in conjunction with electronic apparatus that gives quantitative measurements of the extent of the abnormal combustion. Results obtained by these means are reported with particular emphasis on high speed knock (a problem presently encountered with European cars), preignition and misfiring. On the basis of the test results a technique is developed utilizing the electron scanning microscope to recognize a posteriori if the piston failure is due to knock or preignition.
1973-02-01
Technical Paper
730435
Donald E. Baxa
Noise control has been greatly accelerated by recent legislation affecting industry and its products. The overall effect is still far from complete since the standards provided for by the Noise Control Act of 1972 have not been established. This paper considers the historic cases and laws in the United States which have had and will have the effect of bringing quiet to the citizens of this country. The legal developments included are, Wisconsin's Occupational Hearing Loss Compensation Law, the Walsh-Healey Act, Occupational Safety and Health Act, the Chicago Noise Ordinance, and the Noise Control Act of 1972. A review of the standards presented by each piece of legislation will be given, and their effects on both industry and its products will be pointed out.
1973-02-01
Technical Paper
730427
Kenneth C. Kirkland
A patented test facility has been developed for the purpose of analyzing exhaust noise emissions. The facility isolates the exhaust system noise source and allows noise tests to be conducted under the SAE J366a test site conditions. The exhaust system is piped and positioned in a manner similar to that found on the vehicle. Noise tests are conducted under steady state engine speed and load settings resulting in a high repeatability of test data.

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