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Viewing 164191 to 164220 of 188552
1972-02-01
Technical Paper
720730
Orien A. Kruse
Onan's new 40 in3, heavy-duty, air-cooled gasoline engine offers advantages of 2-cyl configuration in a size range formerly dominated by single-cylinder engines. The twin-cylinder-opposed design results in a compact, quiet, extremely smooth-running engine, easily adaptable to garden tractor installations. The engine features an aluminum die-cast cylinder block. Aluminum die castings are used extensively throughout the design. All components are well tooled for low-cost, high-volume production. A variety of options are available, allowing tailoring the engine to meet the garden tractor manufacturers' specific requirements.
1972-02-01
Technical Paper
720726
Robert J. Dorgan, Russell L. Rio, David M. Latson
The advantages of infinitely variable ratio steering and propulsion for track laying vehicles are well known. Studies and demonstrator programs in the past decade have indicated that the hydromechanical transmission has the most promise of providing infinitely variable ratio for military vehicles. In 1966 the Army launched a program to develop the hydromechanical transmission to “production ready” status. This paper describes that program, the transmission selected, and some of the problems encountered in the transition from the demonstrator stage to one of readiness for military application.
1972-02-01
Technical Paper
720727
D. K. Werle, J. D. Stockham
A parameteric study was made of the variables associated with a rotary brush air cleaner for helicopter gas turbine engines. Tests were conducted at air volumes ranging 3000-8000 ft3/min and brush speeds of 1200-3000 rpm. While centrifugal effects were found to be an important cleaning mechanism, impaction effects significantly improved dust separation at brush speeds above 2400 rpm. On a constant impaction area basis, brushes with 1 mm diameter wires were more efficient than brushes with 2 mm wires. Wires added in the axial direction were more effective than wires added in a radial direction. Separation efficiency at 8000 ft3/min of dust laden air and brush speeds of 3000 rpm approached 100% for size classified test dusts in the 15-35 μm size range. The separation efficiency on a 2.7 μm mass mean diameter test dust was a respectable 66%. Only 7 hp was required to rotate the brush shaft at 3000 rpm; the pressure drop of 4 in of H2O was independent of brush speed.
1972-02-01
Technical Paper
720731
Robert T. Larsen, Arthur Sorenson
The current study proceeds from an experimental observation of crankshaft flywheel whirl to the satisfactory development of a method of analysis. It aims to establish the most simplistic approach compatible with system behavior. The results of this study point to a mathematical model based upon a rigid disk whirling about the end of a flexible shaft. The proposed model represents a sensible compromise between accuracy and simplicity, which leads to a simple expression for the critical whirl speeds in terms of the most significant system parameters.
1972-02-01
Technical Paper
720737
Itzhak Ben-Bassat, Carl H. Wolgemuth
The purpose of this work was to develop a tool for evaluating the performance of different positive-displacement steam expanders. The model reported here allows for two stages of expansion, friction, and heat transfer. The equations developed include also the transient charging and exhaust processes, but do not include the inertia effects in the fluid. These equations are in dimensionless form and the solutions are applicable to all expanders of this type. If expanders of different geometry are to be considered, only the volume equations must be changed to obtain a simulation. The performance (work output and adiabatic expansion efficiency) is shown as a function of breathing number and arcs of admission and exhaust.
1972-02-01
Technical Paper
720735
Terry A. Dunlap, William G. Halvorsen
This paper discusses the nature of noise production of automotive transmissions and the various measures which may be taken to reduce operating noise. The measures discussed include investigation and modification of the gear-shaft system dynamics in both bending and torsion. Also discussed are determination of dynamic characteristics of the transmission housing and ways of reducing the levels of vibration of housing areas and of decreasing the radiation efficiency of those areas.
1972-02-01
Technical Paper
720742
R. N. Klaas
This paper lays out some guidelines for selecting the proper tire for off-the-road vehicles and then maintaining those tires so the machine-tire relationship is optimized for maximum performance. Essentially, this involves selecting the proper size tire, choosing the best available tire design, construction, and compound compromise for specific job requirements, and finally following good maintenance practices on each unit.
1972-02-01
Technical Paper
720739
Elie B. Arwas, John M. McGrew, Leo W. Winn
This paper surveys two bearing approaches that may be considered for gas turbine applications. The first is the hybrid bearing which uses a fluid film in parallel or in series with the rolling-element bearing, and whose objective is to increase the L10 life of the rolling-element bearing in high-load and/or high-speed applications. In the parallel arrangement this objective is sought by load sharing between the fluid-film and rolling-element bearing components. In the series arrangement, the objective is sought by achieving a decrease in the effective speed of the rolling-element bearing. The series approach also provides radial, viscous, damping, and this paper derives the relationships necessary for such design. The second approach is the use of gas bearings as a solution to problems of high-temperature operation. The merits and potential problem areas of gas bearings in advanced gas turbine applications are discussed and some appropriate gas bearing types are described.
1972-02-01
Technical Paper
720740
J. M. Ross
This paper deals with the use of low-cost hydrodynamic bearings in high-speed rotor systems. The advantages of these bearings, including reduced noise, damped vibration, and long life, make them attractive candidates for gas turbine engines. Several well-established designs, such as axial groove, three-lobe, full floating, and tilting pad bearings, are discussed in detail. Also, several lesser known bearing designs are considered. The material and construction requirements are also looked into.
1972-02-01
Technical Paper
720709
Duane L. Keller, Ronald E. Wilson
The application of torque-sensitive drives for combine belt drives affords the advantage of allowing the drive to be normally tensioned at lower tensions but still maintain the aggressiveness to transmit high peak horsepower loads. Dayco's equations will predict drive design (driven and driver axial forces, tight and slack side tensions) for various output loads. Varying the cam actuators surface and ramp angle will increase or decrease the effect of torque sensing. Belt-sheave and actuator surface coefficients of friction were experimentally determined.
1972-02-01
Technical Paper
720707
M. G. Milsted, E. L. Wegscheid
The mechanisms by which airborne sound energy is transmitted into a vehicle cab are discussed. Airborne noise reduction of cabs is seen to deviate considerably from the masslaw behavior of the constituent materials. Various acoustical treatments are evaluated experimentally by directly measuring the noise reduction on a cab-like enclosure. The experimental results agree fairly well with available theoretical methods of computing noise reduction.
1972-02-01
Technical Paper
720710
C. E. McKeon
This paper discusses the development of the driveline torque-sensing coupling that is one of the basic components in the “Load Monitor” draft control system for agricultural tractors. Outlined are the design requirements for the torque sensor, the initial concepts considered, the evaluation and testing procedures and results, the evolution of the early prototypes to the current production level, and a concluding section on extensions of the driveline torque-sensing draft control system.
1972-02-01
Technical Paper
720426
Donald J. Nefske
A mathematical simulation of the operation of a compressed-gas airbag system is developed. A system was built and tested, and the analysis is evaluated on the basis of these tests. Included in the study are nonideal gas effects, manifold and diffuser effects, bag stretch, bag leakage, and overpressurization of the passenger compartment. Interaction between a single rigid object and the bag is also considered. A correlation between bag pressure and the force it generates is obtained. This allows the development of an analytic model for determining the motion of a single rigid mass interacting with a dynamically inflating airbag mounted in a moving vehicle. An application of the model to study rebound of the occupant from the airbag is presented.
1972-02-01
Technical Paper
720424
Trevor O. Jones, Dale M. Grimes, Ronald A. Dork
A general discussion of crash sensor requirements is provided, with emphasis on the advantages of long inflation times. An explanation of the basic radar system is offered, and various designs, broken down both by antenna configuration and carrier modulation, are investigated. After careful study it is found that all radar sensors suffer from the same inadequacy-the inability to correctly classify obstacles into hazardous and nonhazardous categories. Several approaches to solving this problem are discussed. The conclusion is reached that radar crash sensors will be unavailable for MY 1976 air cushion requirements.
1972-02-01
Technical Paper
720425
Keith B. Termaat, Kenneth A. Freeman
Crash sensor interfacing with the automobile must be approached from the occupant protection standpoint. Generation of the crash pulse, which determines occupant response, is affected by complex vehicle variables that often preclude discrimination from noncrash signals. Synthesis of the design solution is approached on a systems basis to match sensor capability to vehicle variables. Reliability is provided for with appropriate design of experiments and statistical analysis.
1972-02-01
Technical Paper
720423
John B. Hopkins, F. Ross Holmstrom, Morrin E. Hazel, Edward White, Timothy Newfell
An anticipatory crash sensor for actuation of deployable passive restraint systems has been developed. The system consists of a 10 GHz continuous wave (CW) doppler radar. In operation, position discrimination is achieved through use of separate receiving and transmitting antennas, located on opposite sides of the front of the vehicle. An object is detected only when within the region of overlap of the two antenna patterns. Velocity discrimination has been achieved very simply in both digital and linear realizations. A threshold circuit permits adjustment of the minimum target size to which the sensor will respond. A variety of circuit and antenna configurations has been examined and constructed to obtain optimal system performance. These include hybrid systems which make use of mechanical confirmation of impact in an intermediate speed range, and more elaborate antenna configurations. Characteristics of typical targets have been determined experimentally.
1972-02-01
Technical Paper
720418
W. R. Carey, T. J. Wissing, R. G. Gehrig, G. W. Goetz, D. A. Larson
Inflatable occupant restraint systems (IORS) are categorized according to high, medium, and low momentum air bag deployment energies. Theoretical flow curves for these categories are presented which minimize deployment accelerations imparted to out-of-position occupants, in particular the standing child. Practical techniques to achieve these flow curves for stored gas, augmented gas, and solid inflators are presented. Aspirating systems are described, and their superiority over direct fill systems is indicated.
1972-02-01
Technical Paper
720421
Lon E. Bell
Within the past several years many crash detector concepts have been evaluated for use in automobiles. The experience gained in the process of detector development has lead to several useful new design techniques. In this paper, under the general categories of design methods and design verification procedures, special applications of failure mode analysis, design perturbation analysis and inadvertent actuation prediction techniques are discussed. The design of rolamite acceleration-time detectors and the concept of fail safe and self-diagnostic design are presented as applications of specific methods.
1972-02-01
Technical Paper
720419
Trevor O. Jones, Oliver T. McCarter
The primary purpose of this paper is to suggest basic crash sensor requirements which will form the basis for discussion of this subject. No attempt has been made in the body of this paper to suggest a particular crash sensor scheme or to recommend specific detectors or devices. However, an Appendix is provided in which is described the current General Motors sensor scheme. As air cushion systems are developed and evaluated, it becomes more apparent that the crash sensor is, perhaps, the most vital system component. In view of the criticality of this system component, a suggested comparative analysis of crash sensors has been included.
1972-02-01
Technical Paper
720304
Calvin L. Stoner
This paper covers structural requirements for certification of a normal category plastic airplane. Due to the lack of service experience and published data, substantiation of the airframe requires special attention. Means for showing compliance with applicable regulations covering proof of structure, fabrication methods, protection of structure, material strength properties and design values, special factors, fatigue strength, and lightning protection are explained. By current standards, a plastic airframe is novel. However, plastics may be the answer to the corrosion and fatigue problems of metal aircraft.
1972-02-01
Technical Paper
720306
Dennis A. Tuck
The FAA Flight Test Branch is now actively engaged in several regulatory development programs using resources made available by NASA, FAA, USAF, and others in industry. These resources include advanced flight simulators, variable stability aircraft, and current aircraft. These tools are in use now to develop standards proposals for supersonic transports, V/STOL, transports, and general aviation aircraft. Critical control and stability parameters may now be explored by FAA flight standards pilots in concert with other government and industry experts to the extent and with fidelity never before possible. An example of this approach may be found in the latest issue of the “Tentative Airworthiness Standards for Supersonic Transports.” The SST performance standards therein resulted from an investigation of several aircraft models in the NASA Ames Flight Simulator for Advanced Aircraft and a small delta-winged fighter loaned by the Air Force.
1972-02-01
Technical Paper
720303
D. Lotan
The paper describes a theory that can be used to explain a mathematical statement of the functioning of an oil system. To arrive at this theory, the rates of contamination of the oil circuits of turbojet engines were investigated extensively, by way of spectrometric oil analyses. The details of the phenomena involved are presented, along with the parameters governing the oil system; a chart for interpreting spectrometric oil analysis data is developed, and the mathematical theory is worked out in detail. There is a relation between the rate of wear of the components of an engine and the rate of contamination of its oil system. By indicating metal particle concentration in the oil, spectrometric oil analysis detects rates of wear high enough to constitute risk of accident due to engine failure.
1972-02-01
Technical Paper
720309
Charles C. Pate, Mahendra K. Punatar, Ray W. Winn
A brief description is given of one approach taken by a manufacturer of light business and personal aircraft to the flutter analysis of propeller whirl flutter, twin-boom aircraft, T-tail configuration, servo tabs, and all-moving tail. Effects of structural variations that may occur in the service life of an aircraft are presented, and the effect of ice formation on control surfaces is discussed.
1972-02-01
Technical Paper
720333
R. L. Barnes
Pilots have to read and analyze much flight information. Conditions that require instant action can be instantly recognized by the use of indicator lights. These lights are grouped into annunciator systems, which have changed from simple, single indicator warnings to complex, multichannel systems. These systems provide an analysis of significant conditions of the aircraft and warn of any changes in this condition. This paper discusses the categories of annunciator indicators, circuit requirements, circuit design, additional input circuits, and application.
1972-02-01
Technical Paper
720327
Leon K. Evans
The present power pack used on the Cessna Model 210 is an electrically driven hydraulic unit. This approach in power-pack design combines the advantages of the electric gear system and the hydraulic gear system without reducing the reliability of the total system. The hydraulic system provides light weight and remote location of power units without the use of large pushrods and their related routing problems. This, plus the low cost of electric power units and the deletion of all hydraulic components from the already crowded engine compartment, provides a very substantial improvement to the aircraft landing-gear system.
1972-02-01
Technical Paper
720274
R. J. Vargovick
A drive-by exterior noise program was conducted to determine the contribution of each car noise source-engine/exhaust, fan, and tire/roadway-to the total exterior drive-by noise of a passenger vehicle. A 1970 high- and low-power sedan and a 1970 high- and low-power sporty compact were utilized in the test sequence. Octave-band and dBA sound levels were recorded with the microphone positioned 25 ft away for various modes of vehicle operation at cruise and wide-open-throttle conditions. Results indicate for cruise (road-load) conditions that: 1. Except for high-performance vehicles, the predominant source of exterior vehicle noise above 500 Hz is tire/roadway noise. 2. The major sources of exterior noise below 500 Hz are both engine/exhaust noise and tire/roadway noise. 3. Fan noise is an insignificant contributor to passenger vehicle exterior noise at present noise levels.
1972-02-01
Technical Paper
720273
Robert L. Paullin, Harvey B. Safeer
In May 1969, the Department of Transportation initiated a study on the magnitude of the transportation noise problem and its potential abatement. This study has resulted in the first comprehensive review and analysis of transportation noise in the United States. As an aid in conducting the analysis, and for continuing use in noise reduction efforts, four computer simulation models were developed. By using the models, it was possible to establish the noise levels which might be expected for different transportation modes as a function of the traffic characteristics peculiar to that mode. In addition, an understanding was developed of the technical, economic, and legal limits of potential abatement means for each transportation mode. The study also dealt with the responsibility and ability of public and private groups to provide the necessary implementation programs to achieve noise abatement.
1972-02-01
Technical Paper
720272
Robert G. Stefanek, Stephen J. Kiselewich
The success of urban automated vehicle networks will depend very strongly on the availability of an efficient traffic management strategy for such networks. Previous papers have discussed an automated network traffic management strategy, known as cycle preprogramming, which appears potentially capable of accomplishing the necessary coordination of vehicle flows in a large automated network. This paper develops a methodology by means of which the efficiency of the cycle preprogramming strategy in managing traffic in a large network can be studied. The methodology is then used to analyze the operating conditions on an example automated network for the Detroit area.
1972-02-01
Technical Paper
720271
Larry L. Howson
This paper discusses the development and preparation for a simulation on the digital computer of an automated roadway network for a new urban transportation system concept called the Metro Guideway, using the 1990 Detroit region as the case study area. The objectives of the simulation are to determine the performance of the system as a function of various design parameters, to develop operational computer programs, and to evaluate the computer hardware needs of a real-world system. The discussion includes a brief description of the case study area and an overview of the mathematical and computer models.
1972-02-01
Technical Paper
720269
Glenn E. Wanttaja
A number of new concepts for moving people by means of automatically controlled vehicles on separated automated roadways have emerged in the last few years. The Metro Guideway transportation system concept described in this paper makes use of a common automated roadway and an integrated multimode system of automatically controlled vehicles for public transportation, personal private transportation, and goods movement. The objectives for the multimodal Metro Guideway system concept are reviewed and a methodology is presented for system evaluation from the perspective of user costs and benefits and nonuser impacts. Transportation facility considerations are developed and technology design choices are illustrated.

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