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The Stopmaster brake, which provides a parking and emergency braking system, is described. The operation of both air and hydraulic actuated brakes is discussed, with special emphasis on the features of the hydraulic system, and the operation and performance of the emergency braking system.

Two flame retardant products based on new reinforced polymers are described and property data are presented. Flame retardant test methods for evaluating plastics are discussed, especially the method used in the new Motor Vehicle Safety Standard 302. Other tests based on ASTM and Underwriters' Laboratories procedures also are presented.

This report demonstrates the scope of the preliminary work required before plastics can be used in the vehicle industry. Consideration must be given to diverse factors such as the special physical properties of the material being used, the influence of the manufacturing process on the properties of the plastic components, as well as the basic design of the item being produced. Illustrated in detail is the plastic air duct used for the Volkswagen Type 411 sedan, with particular emphasis on ambient influences and combustibility. Plastics have become an accepted part of the vehicle construction scene and any increase in the use of plastics will depend upon data being made available to the engineer in usable form.

Acrylonitrile-butadiene-styrene (ABS) polymers are capable of modification either by other polymers or by chemical additives to form alloys. ABS polymers have been successfully alloyed with polycarbonates, polyurethanes, polyvinyl chlorides, glass fiber, and inert fillers, such as calcium carbonate, nylons, chlorinated polyethylene, and chemical fire retardants. In each case the resultant products have an area of value not attainable with the basic ABS polymer.

In bonding two materials differing in coefficient of expansion, one must either contain the stresses due to temperature cycling using a rigid adhesive, or allow the two adherends to expand and contract freely using an elastomeric adhesive. An experiment is described which demonstrates the extent that stresses can be contained when a rigid adhesive is used to bond materials of greatly different coefficients of expansion.

The effect of curing temperature on the peel strength of three different adhesive systems is reported. The adhesive systems were cured at 250 F, 275 F, 300 F, 325 F, and 350 F on aluminium, stainless steel, and titanium surfaces. The adhesives were also subjected to a single and a double cure cycle on four different aluminum alloys. Peel strength was determined at ambient temperature and at -67 F.

For many years axle plants have needed a practical testing method for rating the noise quality of rear axle assemblies before installation in cars. This report describes the development of such a test method. Creation of noise requires an energy source. The energy source of rear axle noise is the periodic variation in tooth meshing action of the gears. The frequency of axle noise is always related to tooth mesh frequency. A previous study of rear axle gear dynamics indicated the existence of a nearly vertical resonance of rear axle pinions excited by tooth meshing action. The dynamic resonant amplitude of the motion of the pinions related directly to the in-car noise quality of the gear sets. In general, other resonances within the drive line-axle housing-suspension system can be excited by gear action and produce “axle” noise.

The ideal characteristics of a high performance adhesive are presented here as the stress-strain data of the adhesive joint between two pieces of metal. Elongation under load and environmental compatibility are two important characteristics that determine high performance capability, in addition to the sheer strength, fatigue strength, and cyclic creep tendencies of the material. Emphasis is on mechanical properties, and tests to determine these properties are described.

Time between overhauls (TBO) of above 2000 hr for certain Lycoming aircooled aircraft piston engines are shown to be practical through the use of modern engine design, materials, and maintenance technology, including the use of spectrograph oil analysis (SOAP). Several examples of extended time programs with their attendant problems are shown for a 150 bhp direct drive, 4-cyl engine and more sophisticated 380 bhp 6-cyl geared and 310 bhp turbocharged engines. Limiting TBO factors and practical limits of TBO are also discussed.

The idea of making a measurement with an energy conversion device called a transducer is presented. Types of transducers are discussed and their important characteristics are defined and discussed. Several examples are presented to illustrate how transducer characteristics and equations of operation are evaluated. Finally, the generalized measurement problem is presented and discussed in terms of obtaining valid data in order that the concept of making measurements can be treated as a science rather than as an art.

Possibilities for the reduction of automobile emissions by changes in gasoline composition have been reviewed. Small benefits are achievable by limiting front end volatility and light olefin content. California has already passed legislation which places limits on these fuel properties. Fuel hydrocarbon type, octane number, and lead antiknock content are interrelated. Maintenance of octane number while removing lead can be achieved by increasing the fuels aromatic content with a resulting increase in some aspects of the exhaust's reactivity. Alternatively, lead may be removed without changing hydrocarbon composition if the engines octane number requirement is reduced. These changes may result in lower exhaust hydrocarbon content. They will result in lower engine efficiency and hence higher exhaust flow rates. The net effect on pollutant emissions is in doubt. Gasoline additives, other than lead, make little direct contribution to the pollutant content of exhaust.

A digital computer simulation of complex, three-dimensional dynamics of automobiles on irregular terrain is described which is suitable for studies related to vehicle braking systems and to the driving task, including the upper limits of control as well as the linear ranges of operation. The reported simulation is an extended version of an earlier, validated mathematical model. A number of refinements and extensions of the analytical treatments of tire forces, suspension properties, and terrain definitions, have been incorporated. Also, analytical representations of the braking system and driveline, and approximations of rolling resistance and aerodynamic drag, have been introduced. Sample outputs of the modified computer program are presented and discussed.

The great number of trailers on the highways has resulted in expanded regulations covering lights and reflectors, and car power circuitry now needs to be made compatible with increased lighting requirements. Standardization is needed with respect to the connection of trailer lights and the grounding of trailer frame to car frame, as well. A standardized car-trailer connector suitable for use in more than one combination of trailer plug with a single-receptacle car connector is another necessity. These requirements suggest the advisisability of developing recommended practices for the above situations. An SAE standard should also be prepared to include portions of current SAE electrical standards now applicable to car-trailer lighting and featuring an expansion into new problem areas in this field.

The development program on the Olympus 593 pure jet twin shaft engine has been in existence about 5 1/2 years. Throughout the program a policy of matching engine rating to aircraft requirements has been adopted. All engine standards have been checked out by extensive bench endurance testing. Performance requirements have been confirmed by testing in altitude cells and by subsonic flight.

A method is presented for measuring individual wheel loadings with strain gages mounted on a rotating axle. The mechanics of the system are discussed and the instrumentation required for obtaining the necessary signal outputs is described.

Aircraft starting and generating systems heretofore have been largely the result of joining together available components. Recent studies have demonstrated that substantial benefits in weight, cost, size, and performance may be realized through a total system approach. This paper identifies the types of information required, and the methods of system analysis employed, to design an optimized system.

Aging of adhesive sealants such as polysulfides and silicones is usually restricted to accelerated aging in ovens and other laboratory environments. A need for extended aging under actual outdoor conditions has long existed. This report describes the results of five-year aging tests on five different types of polysulfide and silicone adhesive sealants under various environments, including semi-arid and marine type outdoor aging sites. These are compared to oven aging and ambient shelf aging results. Data on continuous exposure for twelve months to high humidity with cycling temperatures is also included. The results indicate that a marine climate is the worst exposure condition. The results also show that a manganese peroxide cured to polysulfide is more sensitive to a marine climate than is a lead peroxide cured polysulfide.

The passenger car windshield wiper system design is very dependent upon the vehicle styling. As such, wiper systems are continually being revised or redesigned to accommodate new styling themes and incorporate engineering improvements. The design process is discussed from the initial feasibility phase to the final production release of detailed drawings. Since the application of computers to wiper design has been covered in other articles, the classical approach with little computer usage is emphasized. The various possible system configurations are reviewed in addition to a general discussion of the wipe pattern design, the linkage design, and the considerations for recessed or concealed wiper parking.

The control of ever-increasing air pollution has become one of the most urgent problems of today. Man, through some of his machines, has created an astonishing health problem: he is increasingly fouling his most precious commodity, the air he breathes. Even though machines have been put to shocking and tragic use, man's greatest and proudest triumphs have been produced through the machine. Harnessed power greatly extends the productivity of man and has become necessary to his very existence. Our density is unalterably bound to the machine. We must learn to live with it.

The decade of the 1970's is a crucial one for engineers. Our environment is being fouled-as is the engineer's image when he is singled out as the creator of the sources of pollution. The engineer is now being held responsible to his community, as well as to his profession. The temptation to involve his professional organization in problems which have social and political overtones will surely foster serious disagreement within that organization. He should, instead, involve himself in local politics, where he can develop an audience for his opinions and where he can influence those in power to implement original and effective solutions to environmental problems.