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After pointing out that the publication of articles in the trade and technical journals, to the effect that very considerable weight-reductions in motor-truck construction with consequent savings in gasoline and tires are possible, works an injustice to the motor-truck industry and is misleading, the author outlines some of the reasons why such weight-reductions are very difficult to effect, as well as the possibilities of standardizing axle details. The use of aluminum to effect weight-reduction is commented upon and the various advantages claimed for metal wheels are mentioned. In the latter connection the author points out that, while these claims may be true, they are unsupported by reliable data. The greater part of the paper is devoted to an account of a series of tests conducted by a large coal company to determine the relative merits of wood and metal wheels on its trucks.

The process devised by the author was evolved to eliminate the difficulties incident to the finishing of the spline and body portions of a spline shaft, such as is used in transmission gearing, by grinding after the shaft has been hardened, and is the result of a series of experiments. The accuracy of the finished shaft was the primary consideration and three other groups of important considerations are stated, as well as four specific difficulties that were expected to appear upon departure from former practice. Illustrations are presented to show the tools used, and the method of using them is commented upon step by step. The shaft can be straightened to within 0.005 in. per ft. of being out of parallel with the true axis of the shaft, after the shaft has been hardened, and it is then re-centered true with the spline portion.

Cleveland Section paper - After commenting upon the two contradictory attitudes toward malleable iron in the automotive industry and outlining its history briefly, the authors discuss the differences between malleable and ordinary gray-iron and supplement this with a description of the heat-treating of malleable castings. Five factors that influence the machining properties of malleable-iron are stated. These were investigated in tests made with drills having variable characteristics that were governed by six specified general factors. Charts of the results are presented and commented upon in some detail, inclusive of empirical formulas and constants and deductions made therefrom.

The author believes the piston-ring problem to be an engineering one worthy of serious study and that it should be possible to standardize types and sizes in a way that will go far toward elminating present difficulties. It is stated that cast iron is the only satisfactory metal suitable for use in the internal-combustion engine and that the foundry offers the greatest opportunity for improvement, in the elimination of poor castings. The superiority of individually cast rings is averred and a formula for their composition is given. Leakage and oil-pumping are discussed, followed by comment upon the width and form most desirable for piston-rings; and some of the difficulties of their manufacture are enumerated, together with suggested improvements, inclusive of inspection and testing methods.

After pointing out that the general question of weight reduction is no exception to the fallacies that seem to have beset the development of the automobile from its earliest days, the author outlines briefly the problem confronting the automobile designer. The influence of the weight of the reciprocating parts on the chassis in general and the engine in particular is emphasized as being of greater importance than the actual saving in the weight of the parts themselves, it being brought out that the bearing loading due to inertia is really the factor that limits the maximum engine speed. Reference is made to the mathematical investigation by Lanchester in 1907 of the advantages of using materials of high specific-strength and the conclusions arrived at are quoted in full. A tabulation of the specific strengths of various materials used in automotive engineering practice is presented as showing the advantages of aluminum as compared with steel.

Annual Meeting Paper - Addressing the structural engineer and the purchasing agent particularly, the author discusses the relationship between them and the foundryman with regard to malleable-iron castings and enumerates foundry difficulties. The characteristics necessitating adequate gating for such castings are described and illustrated, inclusive of considerations regarding pattern design, followed by a statement of the considerations that should influence the purchasing agent when dealing with foundrymen. Possible casting defects are described, illustrated and discussed, comment being made upon casting shrinkage and machinability. Improvements in annealing-oven construction and operation are reviewed and the records of 100 consecutive heats in different plants are tabulated. The materials for casting that compete with malleable iron are mentioned and its physical characteristics are considered in some detail.

The author discusses drop-forging practice from the standpoint of the materials used, and strongly advocates a more rigid inspection and testing of raw materials to determine their fitness for use in making automotive forgings. Seven specific possibilities of actual difference between drop-forgings that are apparently identical are stated, the requirements of the inspection of raw stock are commented upon, and the heat-treatment and testing of finished forgings are considered at some length. Tabular data of the chemical analyses and physical properties of 107 different heats of carbon-steel used recently are presented and show a variation in drawing temperatures of 140 deg. fahr. in steels of practically the same chemical composition to meet the same physical-property specification, based on more than 1000 tests on this grade of steel taken from production stock. The concluding summary has five specific divisions.

Dividing the ability of an automobile finish to remain new into the elements of proper quality of the materials, engineering of application systems, methods of application and care of the finish, the author states that the responsibility for them rests jointly upon the manufacturer of the varnishes and paints, the builder of the automobile and the owner of the finished product. Five basic materials that are necessary in automobile painting are specified and discussed. Engineering systems of application and the actual methods of application are treated in some detail, inclusive of drying, and of surfacing or rubbing. The care of the finish is important and the precautions necessary in this regard are outlined. The paper deals with the application and not the manufacture of the different varnishes and paints that are mentioned.

The process of continuous die-rolling and the products possible with this method of manufacture are described and illustrated. The improvements that have been made were the result of efforts to produce more complicated sections by this process, with greater accuracy, and these are discussed at some length. The physical characteristics of steel that must be considered are commented upon and forming that is effected in one pass is described, consideration being given the requirements of rolled forging blanks. The cost of operation is treated and the equipment used is discussed, showing how this process differs from other methods of making the same things, as to both the operations necessary and the character of the product.

The authors state that the coefficient of friction between two rubbing surfaces is influenced by a very large number of variables, the most important being, in the case of an oiled journal, the nature and the shape of the surfaces, their smoothness, the clearance between the journal and the bearing, the viscosity of the oil, the “film-forming” tendency or “oiliness” of the oil, the speed of rubbing, the pressure on the bearing, the method of supplying the lubricant and the temperature. The primary object of the paper is to present the best available data regarding the fundamental mechanism of lubrication so as to afford a basis for predicting the precise effect of these different variables under any specified conditions. Definitions of the terms used are given and the laws of fluid-film lubrication are discussed, theoretical curves for “ideal” bearings being treated at length.

Stating that present internal-combustion engine fuel is too low in volatility for economical use and that this is the cause of engine-maintenance troubles, the authors believe that, since it is not possible to obtain the more volatile grades in sufficient quantity, the only hope of remedying this condition is to learn how to use the heavy fuel, and that the most promising method of doing this lies in the effective use of heat. As the experimental data regarding the best temperature at which to maintain the metal in a hot-spot manifold and the range of temperatures available in the exhaust gases are meager, the authors experimented in the Purdue University laboratory to secure additional data. They present a summary of the results.

The term “oiliness” is defined as that property of lubricants by virtue of which one fluid gives lower coefficients of friction (generally at slow speeds or high loads) than another fluid of the same viscosity. Its importance under practical operating conditions is shown to be greater than is generally recognized. Unfortunately, however, no satisfactory method has ever been developed for the quantitative measurement of this property in comparing different lubricants.

As a result of the general policy of the Motor Transport Corps to standardize the materials used for automotive vehicles for Army Service, in cooperation with the Bureau of Standards, the Society of Automotive Engineers and the automotive industry, the Bureau of Standards has been engaged for some time in developing a standard method for testing brake-linings. While the work is not complete, much information has been gained. This paper reports the progress of the work. The equipment developed and the methods used for both main and supplementary tests are described. Information is given regarding the coefficient of friction, as influenced by various factors. The endurance test, showing the comparative behavior of linings under conditions similar to those of severe service, is believed to be satisfactory as developed. Further work is necessary before recommending the conditions for the other test, intended to determine the relative endurance under ordinary or light service.

The development of air-cooled engines for aircraft never made much progress until the war, when the British attempted to improve the performance of existing engines by a series of experiments leading eventually to the development of aluminum cylinders with steel liners and aluminum cylinder-heads with a steel cylinder screwed into the head. The advantages of these constructions and the disadvantages of other types are discussed. Results are reported of tests at McCook Field on a modern cylinder-design of this type showing good results, that lead to the belief that large air-cooled engines will be produced in the near future, equal in performance to water-cooled engines of the same power.

The author states preliminarily that it is believed that never before in the history of the Society of Automotive Engineers has a single problem been so universally studied as the fuel problem that is confronting the industry today. It is also believed that never before has the industry had a problem which includes such a wide scope of work. The solution calls for the service of every class of engineer, inventor and scientist. The paper does not attempt to give highly scientific information; its real purpose is to appeal for a broader viewpoint and to give illustrations and tests which show that the solution of a problem may lie in an entirely different method than that which often becomes stereotyped by sheer usage, rather than by its specific merit. In the solution of the fuel problem we undoubtedly will have to change some of our old habits, replacing them by studiously worked out viewpoints.

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.

It is of course impossible to consider propeller design very much in detail in a paper of this nature. It can be said, however, that the airfoil theory, in connection with the inflow theory, has given very good results and proved exceedingly valuable for the aerodynamic design of propellers. Both theories, however, in the present state of knowledge, must be applied with a number of empirical factors. Propeller-design theories and the subject of aerodynamics are discussed mathematically, as well as the elements governing the best propeller diameter for obtaining the highest thrust. Consideration is given in detail to steel, adjustable-pitch and reversible propellers as well as to those made of laminated construction consisting of sheets of paper fabric impregnated with bakelite as a binder. The mathematical considerations that apply to propellers when reversed in flight, the time and distance required to stop when landing and the propeller stresses are enumerated and commented upon.

Automobile body building derives its origin from carriage body building, which was highly developed before automobiles were thought of. The introduction of automobile bodies fitted to a metal frame changed body builders' rules and calculations. The influence of the metal frame is discussed briefly and the limiting sizes of body members are considered also. According to the ideas expressed, the weight of bodies can be reduced if the metal frame is designed so as to support the weight of the passengers and the body. The dead-weight also can be reduced if the frame is built in proportion to the amount of weight carried, the number of passengers and the style of bodies being considered. But in the construction of enclosed bodies, as in sedans, coaches and broughams, very little weight can be saved if stability, durability and lasting quality are to be retained.

The field of body engineering is broader than it is ordinarily considered to be; the author's intention is to bring to the attention of the automotive industry the breadth and scope of body engineering and outline the way this side of the industry can be considered and developed. After describing the body engineer's position, the author then discusses at some length the conflict between art and economy in this connection. He classifies a body-engineering department under the six main divisions of body construction, open and closed; sheet metal, body metal, fenders, hood, radiators and the like; trimming; top building; general hardware; painting and enameling, and comments upon each. Following this he elaborates the reasons for need of attention to details in body designing and mentions the opportunity there is at present for bringing the materials used in body construction to definite standards.

The author selects and sets forth some of the main laws and basic considerations influencing carbureter action. A brief defense of the carbureter as a means of supplying fuel to an engine is made, as compared with the fuel-injection method, and conditions in the cylinder, the manifold and the carbureter during normal operation are stated. The relations of throttle positions, manifold vacuum and engine torque are discussed, followed by an exposition of the effect of manifold vacuum upon vaporization. The subject of air-flow in carbureters is treated at some length and the venturi-tube form of air-passage is commented upon in considerable detail. The flow of air through air-valves, fuel-flow and mixture-proportion requirements are given detailed consideration, the last being inclusive of passenger-car, motor-truck, tractor, motorboat and airplane needs. The essentials for obtaining accurate information with regard to carbureter and engine tests are outlined.