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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
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.
1973-04-01
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.
1973-02-01
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.
1973-02-01
Technical Paper
730429
Vincent P. Byrne, John E. Hart
An intake and exhaust system mathematical model has been developed with the ability to predict the effects of specific acoustical elements on acoustic system performance. This paper discusses typical systems, the acoustical elements that make up the system, and a mathematical modeling of a system. It will also cover the effects of changing acoustical elements-exhaust and tail pipe lengths-on a noise spectrum.
1973-02-01
Technical Paper
730414
David S. Gedney
Highway design and construction processes can and do have significant impact on a community and its environment. Geometric design innovations can significantly reduce air and noise pollution for a completed facility, but construction noise is especially difficult to control within tolerable limits unless engineers and equipment manufacturers seek better methods through investment in additional cost and improved technology.
1973-02-01
Technical Paper
730220
R. W. Alexander, H. S. Kert
Vibrations encountered in motor vehicles operated at speeds in excess of 60 mph are discussed in terms of source analysis, component response, and vehicle sensitivity relative to customer acceptance standards. Two actual case histories are used to illustrate the utility of component order alignment charts, the effectiveness of component response control and the use of sensitivity charts for comparative analysis of subjective data.
1973-02-01
Technical Paper
730259
Floyd Brouwer
The purpose of this paper is to show the development of the Dynamic Rubber Test Machine as an engineering and production (quality control) tool from the standpoint of a machine supplier. Problems encountered in the design, fabrication, preshipment checkout, and installation of equipment into customer's facilities are discussed. Correlation of equipment is explored as it relates to the dynamic spring rate and the damping constant of elastomer products. Certain techniques and hardware adaptations have aided in improving the repeatability of tests of the resonant beam system. The information given is not intended to be all inclusive, but as a report of the work in this field to date.
1973-02-01
Technical Paper
730266
A. D. Anderson
Representation of elastomers for use in modeling of linear systems requires great care in the acquisition of test data. Current industry-standard test techniques are not adequate for quantitative description of elastomers subjected to small amplitude sinusoidal excitation. Equally important to accurate dynamic testing of elastomers is parameterization of the test data for use in modeling of systems. The paper discusses testing and parameterization techniques used to describe elastomers for use in a linear, low-frequency vibration model of an automobile. Accuracy requirements of test instrumentation, selection of suitable linear elastomer models, and interpolating functions (used for equivalent linearization and ambient condition corrections) are discussed in some detail.
1973-02-01
Technical Paper
730265
A. S. Paul, B. M. Hillberry
Dynamic analysis of the resonant beam machine is presented. Equations typically used to determine the dynamic properties of a rubber product are derived from a simplified model. A complex mathematical model representing a more realistic parametric system identification is formulated. Using the complex model as standard, the errors in the results from the simplified model are identified quantitatively, and it is shown they can be considerable. The sensitivity of the errors to the system parameter variations is also shown. These machine errors may be virtually eliminated by measuring the transmitted force and displacement across the sample.
1973-02-01
Technical Paper
730268
Robert C. Puydak
Dynamic test equipment is used to characterize elastomers and compounding ingredients for the purpose of selecting those most suitable for the various types of dynamic mountings and to develop formulations with balanced properties. Key measurements include modulus under conditions of dynamic vibration, damping, and the ratios by which these quantities change with changes in frequency, amplitude, and temperature. By appropriate selection of test specimen configuration and test conditions, additional data are generated which can guide the designer in the most effective use of the materials available and help define the relationships between the properties of mount materials and their effectiveness in controlling vibrations in vehicles.
1973-02-01
Technical Paper
730247
Masanori Hanaoka, Sadafumi Fukumura
At low engine speeds, predominant noises are valve train noises that occur at the instant the valve opens and closes, and those that occur while the follower is on the cam lobe. Valve noises are caused by impacts, and their sound intensity is proportional to the impact speed. Follower noises are caused by frictional vibrations due to metal-to-metal contact at points where oil film thickness becomes zero. Irregular contact surfaces increase these noises. Valve train noises at high engine speeds are caused by irregular valve behavior. The profile of the new cam design is expressed by “n” th-order Fourier series in 360 deg continuously, and has no high-order harmonics that resonate with the natural frequency of the train. Its wide parameter permits design of a most reasonable acceleration curve. Valve motion is thus improved and noise is reduced.
1973-02-01
Technical Paper
730287
Richard N. Tedrick, Roger W. Heldenbrand
A program, under the sponsorship of the U.S. Air Force Aero Propulsion Laboratory, is now under way to provide the computational tools necessary to predict noise signatures for small turbopropulsion engines and to design attenuation equipment as required to meet specific low-noise goals. The 24 month program, scheduled for completion in August 1973, involves the analysis of turbine engine noise prediction and attenuation methods, as well as the experimental verification of these analyses with full-scale hardware. This paper reviews the methodology development phases and examines acoustical data from bare and attenuated engine tests.
1973-02-01
Technical Paper
730346
G. M. McRae
A NASA sponsored program to develop noise-reduction modifications for the JT3D and JT8D engines was initiated in August 1972. New higher flow single-stage fans are attractive and result in higher bypass ratios with improved thrust and fuel consumption and reduced jet velocities. Fly-over noise reductions as great as 20 EPNdB are shown for the modified engines with nacelle treatment. Engine certification can be completed and production hardware for fleet retrofit or new airplanes can be provided by late 1975.
1973-02-01
Technical Paper
730691
Clarence Hofelt, Kenneth J. Gormish, David A. Corcoran
High-speed tire uniformity machines may be used to measure three-dimensional tire force variations (tire uniformity) that cannot be measured at low speeds. Prototype machines described and some inherent problems outlined. Typical tire force variations, the influence of certain variables on such force variations, and the significance of these force variations are also given.
1973-02-01
Technical Paper
730899
Richard D. FitzSimmons, Walter C. Hoover
No greater contribution seems to exist for improving supersonic transport economics than by improving the state of the art of jet noise suppressors. Exact matching of thrust requirements for supersonic cruise, transonic acceleration, climb, and especially takeoff-climb is complex. The present design becomes an equivalent five-engine configuration, where the extra thrust is required to enable environmental levels of FAR Part 36 to be achieved. The added size is required first to allow for engine throttling during takeoff run to provide reduced exhaust velocity and exhaust gas temperature consistent with suppressor structural limits, and secondly to make up for suppressor losses at takeoff flight speeds. As the engine selection must be closely tied to airplane selection, substantiation of the 2.2-M airplane selection is described.
1973-02-01
Technical Paper
730898
RICHARD L. FOSS, ELLWOOD L. BRAGDON
Operation of a U.S. developed supersonic transport must and will meet community noise standards. This paper examines the airport noise problems of large transport aircraft, highlights critical considerations, and then studies possible solutions available from advanced propulsion technology. Engine sizing requirements to meet SST payload-range and airport performance criteria are reviewed first, and the impact of noise on the engine size and aircraft performance is then identified. Relief offered by noise suppressor development and technology advances that can be foreseen in the next decade for turbojet and turbofan engines are described. The advantages offered by a duct heating turbofan engine cycle are discussed. The potential offered by variable cycle engines to provide low noise characteristics with minimum penalty on performance are shown, and the practical restraints imposed on this potential by airframe aerodynamic noise is illustrated.
1973-02-01
Technical Paper
730873
R. L. Mann
A major noise source on construction equipment is the cooling system when tested according to the French Noise Test Procedure. This paper describes the procedure and methods used to reduce economically the Case 580B CK loader-backhoe cooling system noise to 75 dB(A), well below the French limit of 80 dB(A) for the whole vehicle, and remain within the desired physical and performance constraints. This was accomplished primarily by reducing fan speed and using a larger capacity radiator to maintain adequate cooling.
1973-02-01
Technical Paper
730874
G. E. Maroney, L. R. Elliott
Satisfactory control of fluid power system noise is dependent upon accurate knowledge of component noise levels. One component which contributes to the total system noise level is the hydraulic pump. There are test methods available for measuring and reporting airborne pump noise. However, these test methods need to be carefully examined to insure that proper constraints are placed on the various hydraulic and mechanical factors which affect the accurate measurement of pump airborne noise. This paper describes the major hydraulic and mechanical factors that affect the measurement of pump airborne noise. Experimental data are presented to illustrate the variation that can result due to such factors as the pump mount, fluid lines, and the drive shaft. Techniques for reducing the variation due to these factors are presented for the reader's consideration.
1973-02-01
Technical Paper
730850
Charles D. Wood
Circumstances and results of tests of a three-chambered REDSOD built for attachment to a Caterpillar D9 tractor are discussed. The Caterpillar D9 tractor was chosen for its drawbar capability of 4000 lb/ft of width, bare weight of approximately 70,000 lb, and 10 ft width. Tests in straight trenching operations were performed at two sites: one in an area with a clay overburden, the other in sand. From the data presented, it is concluded that a REDSOD machine, with a 1200 ft3 min air compressor, handled by a skilled operator, can produce a 2 ft deep trench at approximately 2000 yd3/h. The noise level is not damaging to operator or adjacent structures or personnel. The use of higher air pressures increases production rates. The recoil produced by REDSOD has no appreciable effect on production rate or tractor reliability.
1973-02-01
Technical Paper
730824
J. Huot de Longchamp
A short survey of the literature about human tolerance to vibrations and about seat transmissibility is presented. A brief summary of European regulations concerning seat characteristics will include not only vibration absorption requirements but also recommended dimensions and necessary adjustments. Safety rules as issued in some countries, in particular for tractor seats, are also discussed. The practical problem of making a seat in accordance with all these factors at a reasonable cost with durability and easy adaptation to the unskilled user will be discussed as a compromise. Conventional systems and new trends are briefly indicated.
1973-02-01
Technical Paper
730823
Larry F. Stikeleather
Since vehicle seats interact dynamically with the human body, testing the response characteristics of such seats for proper application is important. Likewise, the methods and techniques used for such evaluations are equally important if meaningful results are to be obtained. This paper discusses two quantitative test procedures applicable primarily to judging the relative performance of several seats with regard to dynamic characteristics. In particular, the equipment and procedures necessary to plot seat transmissibility are discussed and specific example data are shown for two suspension seats and a static cushion seat. Also, equipment and procedures for assessing the relative dynamic response index (DRI) are discussed and example results for a suspension seat and a cushion seat are included.

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