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1974-02-01
Technical Paper
740606
William H. Close
Based on the past research of the U.S. Department of Transportation, this paper is an attempt to make the case for tire noise regulation and to illustrate the implications of such regulations to tire users. The paper examines the effects of speed, load, tire tread type, road surface, and placement of tires on combination truck vehicles insofar as passby sound levels are concerned. A concluding table of expected roadside sound levels based upon typical tire use indicates the potential restrictions in tire types that are inherent in presently proposed federal noise regulations on interstate motor carriers. It is concluded that as significant technological improvements are implemented in the design and regulation of truck engine noise, more severe tire user requirements will follow in order that tire noise keep pace with declining engine noise.
1974-02-01
Technical Paper
740608
R. F. Miller, D. B. Thrasher
This paper discusses the importance of the spectral distribution of the energy in the sound to the dB(A) level of the usual passby test. A described technique obtains reproducible “real-time” spectra from the nonstationary sound field. Doppler effect and source frequency shift are quantified in relating these spectra to the tread pattern repetitions. Inverse square law fitting is viewed through the two-source-microphone relation which changes during the spectral window period. Spectra are shown for 6, 12, and 50 ft (1.83, 3.66, and 15.2 m) passby microphones and for a microphone carried on the truck.
1974-02-01
Technical Paper
740607
G. R. Thurman
The sound level of crossbar-type truck tires was found to be only slightly affected by the texture of the portland concrete road surfaces used. Rib-type tires showed higher noise level on coarse than on smooth surfaces, but the ranking of different tires was unaffected. Clearance of the truck bed above the tire was relatively unimportant. Noise level increased with increase in speed. Sound persistence after truck passby is related to tread design and possibly to the radiation pattern from the road-tire interface.
1974-02-01
Technical Paper
740598
Jim Hanks, Charles Selby, Philip Loken
This paper discusses bearing arrangements designed to maximize stability and load capacity within available envelope dimensions. Also presented is a means of negating the detrimental effects of cylinder reactions in a pneumatic clutch, while at the same time increasing the torque-to-space ratio. These concepts were realized during a study expressly intended to view the various design elements with the requirements of a diesel truck fan clutch in mind. Further, the study resulted in the development of a nonmodulating, direct acting thermal control valve, specifically engineered to complement the action of a pneumatic fan clutch as part of an overall temperature controlling system.
1974-02-01
Technical Paper
740489
James F. Woodall
The FAA retrofit feasibility program is a success story. The cooperation of the aircraft industry in general, and the FAA's contractors in particular have made the success of the program possible. We can now state that all JT3D- and JT8D-powered aircraft can meet reduced noise levels, such as FAR 36 levels, by means of technologically feasible and economically reasonable nacelle retrofit solutions. These solutions will not aggravate the energy crisis by virtue of a negligible increase in fuel consumption for the nominal flight conditions. A Notice of Proposed Rulemaking (NPRM) is about to be disseminated which could lead to the requirement that all JT3D/JT8D-powered aircraft be retrofitted by 1978 with quiet nacelles so that FAR 36 requirements can be satisfied.
1974-02-01
Technical Paper
740485
Richard W. Niedzwiecki, Robert E. Jones
The “Experimental Clean Combustor Program” is a contract effort with primary objectives including the generation and demonstration of technology for development of advanced commercial CTOL aircraft engines with lower exhaust emissions than current aircraft, and the demonstration of this technology in full scale engines in 1976. The program is being conducted in three phases. These consist of screening of low pollutant combustors, refinement of the best combustors and engine demonstration of the best combustors. The combustor screening phase was initiated in December 1972 and is currently in progress. Contracts were awarded to Pratt & Whitney Aircraft and the General Electric Company to evolve combustors for the JT-9D and the CF6-50 engines respectively. Pollution goals are emission index values of 20 and 4 for carbon monoxide and unburned hydrocarbons respectively at engine idle conditions, and an oxides of nitrogen emission index level of 10 at engine takeoff conditions.
1974-02-01
Technical Paper
740492
Gordon Banerian
This paper describes a variety of methods employed in the past to modify or suppress jet noise. Some of the intriguing aspects of the factors that contribute to noise suppression are brought out. The paper concludes that a systematic study of the physics of jet suppression, in place of the ad hoc methods used in the past, is required if the concepts involved are to be utilized for design and accurate predictions in the quest for the quiet aircraft.
1974-02-01
Technical Paper
740490
L.E. Stitt, A.A. Medeiros
The purpose of the Refan Program is to establish the technical feasibility of substantially reducing the noise levels of existing JT8D powered aircraft. This would be accomplished by retrofitting the existing fleet with quieter refan engines and new acoustically treated nacelles. No major technical problems exist that preclude the development and installation of refanned engines on aircraft currently powered by the JT8D engine. The refan concept is technically feasible and provides calculated noise reductions of from 7 to 8 EPNdB for the B727-200 aircraft and from 10 to 12 EPNdB for the DC-9-32 aircraft at the FAR Part 36 measuring stations. These noise levels are lower than both the FAR Part 36 noise standards and the noise levels of the wide-body DC-10-10. Corresponding reductions in the 90 EPNdB footprint area are estimated to vary from about 70% for the DC-9 to about 80% for the B727.
1974-02-01
Technical Paper
740467
W. L. Jones, L. J. Heidelberg
A summary is presented of an acoustic test program for investigating engine noise suppression and jet/flap interaction noise associated with an EBF STOL powered lift system. A highly suppressed TF-34 engine and EBF wing were used in the investigation. The engine was suppressed 21 PndB to a level of 94 PndB. An UTW powered lift system was tested with conventional, mixer, and decayer-type nozzles. The configuration with velocity decayer nozzle and acoustically treated shroud had the lowest noise (98 PndB). An OTW configuration with non-decayer nozzle was about 10 dB quieter than the corresponding UTW system. UTW and OTW noise data are compared with scale model correlations.
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.
HISTORICAL
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.
HISTORICAL
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.
HISTORICAL
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.
HISTORICAL
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.
HISTORICAL
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.
HISTORICAL
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.

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