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THE truck manufacturers have made available to fleet operators a wealth of truck chassis with sufficient models and interchangeability of units to create special models to meet any transportation job requirements no matter how particular or peculiar. Within reasonable limits, the first costs of these chassis are indicative of relative chassis strength, durability, and ability. The selection of a chassis cannot be made from first cost or from operating cost expectancy alone, for these two go hand-in-hand to form the total cost and either may be increased with impunity if the overall cost of transporting the product is thereby decreased. One of the most important requirements in the selection of a chassis is a thorough operation and transportation job-analysis. Other considerations include availability of service, inherent safety, legal limitations, and appearance.

MAINTENANCE economy is seldom a realization unless sufficient consideration has been given to the major factors entering into the cause for maintenance. The expenditures necessary to correct normal wear conditions often represent a very small portion of the total maintenance cost. The operator is presented too frequently with the problem necessitating design corrections before the truck has operated many thousand miles. The responsibility for failures of this nature may rest with either the purchaser or the manufacturer. The purchaser may, due to insufficient thought having been given to the contemplated assignment of the truck, misinform the manufacturer as to the load to be carried or the terrain to be traversed; or his appropriation for purchase may be insufficient for a suitable piece of equipment. The manufacturer, on the other hand, may accept the order, knowing that he cannot furnish suitable equipment.

THE introduction to this paper includes definitions of the major items under discussion, and is followed by a discussion of the materials most widely used in metal-aircraft construction and their important physical properties. In the remainder of the paper are described some of the problems encountered in metal construction and the processes that have been developed to facilitate manufacture. The following specific items are discussed: (1) Design, (2) Tooling, including lofting, (3) Fabrication, (4) Assembly, (5) Inspection, and (6) Protective coating. Special equipment and tools are illustrated.

BY their lack of uniformity and disregard of scientific and economic fact, legislative restrictions on motor-transport vehicles now in force in the states militate against efficient transportation and thus retard economic recovery. In this indirect way and in several direct ways the same situation presents problems to truck builders. Variations in state requirements necessitate undue diversity of designs, present difficult engineering problems, discourage enterprise, threaten the American system of production and penalize good engineering and sound manufacture.

Railroads are facing a crisis in operating costs, the urge toward reduction of unnecessary weight has become widespread and the crusade for noise abatement is no longer to be denied, according to the author. The pneumatic-tired railroad-coach not only answers these requirements, he says, but anticipates a demand for a new traveling comfort. The desire to rubberize railroad equipment is old but much fruitless research has resulted from directing it chiefly toward solid-rubber or cushion tires. Road and rail surfaces present entirely different problems so far as the tire is concerned. No uniformity of conditions obtains on highways but rails are even and smooth. A badly aligned joint such as would wreck a metal wheel makes no impression on a pneumatic tire. As simple as the tire problem may seem, its solution represents years of courageous and skillful research on the part of the Michelin company in France.

TO solve fleet-operation problems successfully, a professional consciousness is needed among the supervisors and the engineers engaged in the operating field, awakened by analyzing and making known generally the methods and practices used by the operators of individual fleets of motor-vehicles, according to the author. In developing his subject he asks the following questions and comments upon them: Has the operator any influence on design? Is that influence good or not? Whatever the influence is, can it be improved and made more effective? If it can be made more effective, how can this be done? If it cannot be made more effective, what is the reason? Regardless of variations in duties and of conditions in organization, each large-scale operator is vitally concerned with matters of design and construction.

Solicitation of sales and the delivery of the product to the customer constitute the most important operative features of the motor-truck fleet supervised by the author. Endeavor is made to install the vehicles in the various fields along standardized lines. The volume and the extent of the business and the topographical conditions of each locality determine the size and the mechanical equipment of the vehicle that is employed, and it is installed only after a study of all the conditions pertaining to its operation. Adequate training of vehicle operators, not only along mechanical lines but also as direct sales representatives of the company, is made a feature; and so is accident prevention. These interests are promoted in various standard ways and are furthered by the publication of “house organs.” After a vehicle is installed the slogan adopted is: Keep It Moving With a Pay Load.

The author surveys some of the general conditions prevailing in the street-railway field and the prospective development of a new type of service, in discussing the necessity for closer cooperation between the engineers of the automotive industry and the operating organizations of the railways, the idea being to develop flexible transportation-equipment that will coordinate with the operation of present railway-transportation facilities and to promote the utilization, wherever feasible, of railway power-supply in the employment of flexible bus-type equipment in supplementing and extending railway-organization service. Changing conditions are outlined, the influences tending toward flexible equipment are stated, and the differences of engineering practice pertaining in the railway and automotive fields are commented upon to show wherein railway and automotive engineers can cooperate.

The author (Chicago Tractor Meeting paper) divides the history of the application of mechanical power to farm work into three periods, reviews each one and comments upon the various phases of progressive development that influence the type of tractor most desirable for satisfying present needs. The requirements of farm work are outlined, and the different types of tractor built and being constructed to meet these demands are reviewed, discussion of large versus small tractors, type of drive, power needed, control, methods of operation and the factors constituting general-purpose service being included. So far as adopting the tractor for farm usage is concerned, the author believes that the present limitation of such utilization lies with the tractor industry and with tractor engineers, rather than with the farmer.

The author enumerates the distinctive features of buses designed for city, for inter-city and for country service and comments upon them, presenting illustrations of these types of bus. Steam and electric motive power are discussed and the chassis components for bus service are considered in some detail. The general types of bus body are treated, together with the influences of climatic conditions and local preferences. Comfort and convenience factors are discussed at some length and the problems of heating, lighting and ventilation are given constructive attention. Fare-collection devices and methods are commented upon, and the State and local legal regulations are referred to in connection with their effect upon bus operation. Illustrations are included and a table showing condensed specifications for city buses is presented.

Stating that asphalt, brick and concrete-slab road-surfaces are the only pavements that have given satisfaction for automobile traffic, the author believes further that thus far the concrete-slab surface is the only one worthy of consideration for such traffic. He discusses the merits and demerits of these surfaces and includes an enumeration of the factors that combine to produce a thoroughly satisfactory road surface. Passing to a detailed review of the bearing value of soils and the correction of road failures, the author presents data and illustrations in substantiation of his statements and follows this with a consideration of the reinforcing of a concrete road-slab with steel.

The paper treats of the service, commercial and technical aspects of the subject in turn. The author calls attention to the fact that there can be no such thing as free service, because the customer pays in the end, and gives a specific definition of service. He argues that the engineering departments should urge upon merchandising departments intelligent distribution through dealers, the stocking of an adequate supply of parts and the maintaining of a well qualified mechanical force for the purpose of making engineering development work in the form of farm power automotive apparatus effective. There is a great need for a suitable system of training mechanics for tractor service work, and there should be a definite plan to assure that men making repairs and adjustments in the field are well qualified.

To test tractors for results valuable to the user, the reliability, durability, power, economy and utility should be determined. Standard tests measuring tractor utility and reliability are impossible practically and durability tests would be an extensive project, but tractor and engine-power tests and tests of the amount of fuel required for doing a unit of work can easily be made. The University of Nebraska tests described were for belt and drawbar horsepower and miscellaneous testing for special cases. The four brake-horsepower tests adopted are stated. Tractor operating conditions are then reviewed. The drawbar horsepower tests include a 10-hr. test at the rated load of the tractor, with the governor set as in the first brake-horsepower test, and a series of short runs with the load increased for each until the engine is overloaded or the drive wheel slips excessively, to determine the maximum engine horsepower.

The best weight for a tractor of given horsepower must be a compromise based upon a mean of the many conditions to be encountered by a given machine or by different machines of the same model. While the weight logically will bear some relation to the drawbar pull, the latter in turn depends upon tractor speed. The next item is weight distribution, which requires the utmost skill of the designer; this is elaborated and diagrams are shown of tractors operating in comparatively firm and in soft ground, ascending a grade and when the drive-wheels are mired. The four-wheel-drive tractor requires a modification of the foregoing analysis and the diagrams are applied to afford a similar analysis for this type. The author's conclusion is that, while careful engineering will make the light-weight tractor of conventional type stable under most conditions, there is a possibility that any future trend toward lighter machines will open the field to other types.

THE United States was practically unprepared in the field of military motor-transport at the beginning of the war. Due largely to the cooperation of the Society of Automotive Engineers and its members individually, this handicap was overcome and a position stronger in this respect than that of any of the other belligerents was attained. The early efforts and the cooperation between the Society and the various Government departments are described, especially with reference to the Quartermaster Corps which at that time had charge of all motor transportation. Regarding the Class B truck, it is shown that the Society acted as a point of contact between the various members of the industry and the War Department and, although not fostering any program or plan of its own, it was largely responsible for the success of the standardization program conceived and carried out by the Army.

The author states as his object a review of what has been done and what must be done to make tractors successful in operating on low-grade fuels, especially kerosene. He takes up in order the four principal methods in common use of applying heat to vaporize kerosene, pointing out the advantages and disadvantages of each method and of its modifications. The author then cites various experiments with different types of carbureters in burning kerosene, drawing at length upon his own experience in this connection. He cites difficulties with gas distribution, manifold condensation, pistons and spark-plugs and points out that carbureter design is inseparable from considerations of tractor engine and manifold design. That better progress has not been made in the past in developing kerosene-burning tractor engines is stated to be largely owing to the fact that there has not been sufficient cooperation between engine and carbureter manufacturers.