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The results of some tests recently completed are presented. No attempt is made to develop the theory involved. It is intended to describe only the actual tests, the conditions under which they were carried out and the results obtained. Superficially, it would seem obvious that the torsional strength of a multiple-splined shaft is greater than that of a full round shaft having a diameter equal to the small diameter of the splined shaft. Data on this and related questions were sought experimentally. A series of tests was run on 15 carefully machined shafts. The dimensions shown are the actual ones of the test-pieces, there not being more than 0.0005-in. variation in any shaft from the diameters shown. Heat-treating was very carefully carried out, and each specimen carefully checked by Brinell instrument on the ends and by scleroscope throughout the length. The Brinell numbers were all between 220 and 235, and the extremes of scleroscope hardness were 38 and 43.

The time has come when greater attention must be given to the smaller parts and the various appliances found on automotive machinery. Previously, investigations have been made by the research laboratories of a few companies manufacturing engines, carbureters and some other parts, but chiefly engines; by the laboratories of research corporations, including the Bureau of Standards and the Bureau of Mines; and by the engineering laboratories of colleges and technical schools. The number and value of the researches that can be conducted and reported on from time to time by these agencies depend entirely upon the appropriations that they can obtain by act of legislation and upon the personnel of the staff that can be attracted by the opportunity to do this class of work.

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.

In recent years automobile engines for racing purposes have been very generally rated in accordance with their piston displacement. The natural result has been to encourage the highest possible engine speeds to attain the greatest possible piston displacement per minute. Features of engine design that have been developed under this rule include enormous valve areas, usually obtained by a multiplicity of valves, huge inlet pipes and carbureters, extreme valve-timing and very light reciprocating parts, all of which are undesirable in commercial engines. To encourage the design of engines of a type developing higher efficiency at lower engine speeds, the suggestion is made that a rule be formulated under which cars will be rated in accordance with the piston displacement per mile actually used by them. Such a rule would involve rear-wheel diameter and gear-ratio, as well as the piston displacement of the engine.

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 paper is divided into three parts; the fuel problem, the selection of the most economical internal-combustion engine for adaptation to automotive purposes and the details of the development work undertaken. After stating the fuel problem, inclusive of production, volatility and price charts, the methods of increasing the engine-fuel supply, the characteristics of present engine fuels and general considerations regarding the selection and adaptation of the most economical engine are discussed. Classifying internal-combustion engines as being of low, medium or high compression, the essential factors, advantages and disadvantages of each class are commented upon in detail. High-compression engines are classified, as to their method of injecting the fuel into the combustion-chamber, into the three general classes of air, gas-pressure and mechanical injection.

Following a review of some of the factors that are productive of excessive weight in a motor vehicle, which causes fuel wastage, and a statement that a more thorough standardization of frames and other parts would eliminate much of this waste, the author presents in detail frame-stress calculations intended to enable the designer to proportion frames and parts with this end in view. Shearing stresses are treated in a similar manner and for a similar reason, use being made of diagrams that facilitate analysis of specific instances cited and being inclusive of a table of bending-moments derived from the diagrams. Laboratory tests of the ultimate strength, elastic limit, yield-point, elongation and reduction in area of materials are then described in some detail and the results obtained stated.

The aim of this paper is to stimulate thought on how to accomplish the greatest possible economy in transportation over highways. The fundamental thought is that the expense of highway transportation involves a large number of items that can be grouped into those directly concerned with motor-truck operation and those involving the highway, and that highways and motor vehicles should be adapted mutually so that the greatest economy of transportation will result. Urging that the automotive and the road engineer cooperate in gathering information that will give them a more definite basis upon which to design the truck and the road, the present rapid destruction of roads is discussed and remedial measures suggested. The designing of motor trucks to conserve the roads is treated at some length and a plea for cooperation between the Society and the highway officials is made.

The majority of the reputable truck builders are attempting to build a high-quality product that will operate over a period of years with the minimum of maintenance expense; however, many designers lose sight of the effect of shocks and strains, which is of even greater importance. Stating that a truck is scrapped for some one or a combination of the three reasons of obsolescence of design, wear on vital parts that cannot be replaced economically and failure of parts due to shock loads, fatigue or crystallization, the author comments upon these and then discusses chassis strains under five specific headings, illustrations also being given.

The paper surveys the differences between American and European conditions in the automotive industry and then considers briefly the reasons for them. The governing conditions are stated and their effects are traced. The subjects discussed include motorcycles and small cars, road conditions, car idiosyncracies, selling conditions in Europe, and a comparison of design in general. The differences of practice are stated and commented upon. Six specific points are emphasized in the summary. The author states that the outlook for American cars the world over is seemingly good. In recent American designs, equal compression - volumes are often assured by machining the heads; six-cylinder crankshafts have seven bearings and are finished all over in the circular grinding machine; pressure lubrication is used for all moving parts of the engine; and in all ways the highest practice is aimed at. America is trying to improve the quality without increasing the cost.

The author considers first the materials available for construction, in connection with the S.A.E. standard specifications, and presents a comparison of the different metals with comments thereon. In regard to metallurgical problems the designer's first task is to determine what the various stresses in the parts are and their magnitude; hence, a true appreciation of the terms “shock” and “fatigue” is necessary; a somewhat lengthy explanation of their meaning is given. The construction features of the different parts of the tractor are treated in general, no attempt being made to cover details; comments are presented on front axles, wheels, bearings, cylinders, valves, valve-seats, transmissions and gears. Heat-treating is then considered in some detail, three specific reasons for annealing before machining being given and five which are governing factors in regard to heat-treatment in general.

Stating that it is conceded by engineers that weight reduction is desirable economically but that it is not unusual to find that weight reduction is looked upon as incompatible with reliability and road-holding properties, the author outlines briefly the normal weight-distribution in an automotive vehicle and gives a short analysis of the power required to drive it having in mind the necessity of reducing the absolute friction-loss. The use of aluminum for various parts is debated, especially those in which reliability is distinctly a function of lightness and not of weight such as engine pistons, and the application is made general to cover all parts of an automobile in which the stresses are determined by road shocks and speed. The trend of design in general and recent research in particular are stated to be along the lines of weight reduction without any sacrifice of essentials.

The author describes the type, size and general characteristics of the engines with which the German submarines were equipped at the time of the surrender, after having personally inspected 183 of them at that time, and then presents the general details of construction of these engines, inclusive of comments thereon. The maneuvering gear for such engines receives lengthy consideration and the reliability of engines of this type is commented upon in some detail, the author having confirmed his opinion that the German submarine engine is extremely reliable. One of the controlling factors in the design is that the Germans had investigated steel casting to the point where the successful production of steel castings was an ordinary process, and the author believes this to have been largely responsible for the success of the German submarine engine.

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.

The paper is devoted more especially to enclosed body construction, with the object of creating a closer relation between the chassis and the body designer, from the viewpoint of an automotive body constructor. After enumerating what are probably the most important materials that enter into enclosed-body construction, inclusive of glue, the author outlines what constitutes the proper seasoning of wood, this being very important because very little all-metal or steel construction has been developed as yet for enclosed bodies, owing to the fact that many parts are required that necessitate using wood. Chassis deflection is discussed in its relation to enclosed-body construction and an outline is presented of body-construction development in general. The author believes that body construction will not be changed radically until either the basic type of design or shape is transformed or there is a firmer foundation to build upon.

Statistics taken from a report made by the Department of Agriculture regarding the number and size of farms in the United States indicate that approximately 2,580,000 farms are available as a market for the isolated gas-electric lighting plant. The common types of lighting plant are classified in three groups, each of which is subdivided into three classes, and these are illustrated, described and discussed. The characteristics of the ideal farm lighting-plant are enumerated and discussed as a preface to a somewhat lengthy consideration of the factors that influence the design of the component parts, which are grouped as pertaining to the engine, the generator, the switchboard and the battery. Storage batteries are still considered the weakest part of the isolated plant and they are specially commented upon. The author emphasizes that much still remains to be accomplished as regards the stability of design, reliability and economy of the isolated plant.

Aviation has no perfect analogy, for it has no precedent. Two classifications are made. Scheduled service includes the carrying of mail, express or passengers on a definite and regularly maintained schedule, independent of, or supplementary to, other forms of transportation. Special service includes pleasure flights, oil-field survey, selecting industrial land-sites, planning cities, aerial photography, forest-fire patrol, visiting remote points, exploration, aerial advertising, delivery of perishable products, real-estate survey and industrial purposes. Each of these classifications requires different equipment, organization and operating personnel. The equipment requirements and the reliability of aerial transportation are discussed, the necessity for suitable terminals and federal flying regulations are emphasized, the subject of insurance is commented upon and the development of aerial commercial transportation is outlined.

The five fundamental criteria of the performance of a motor vehicle as a whole are stated. Riding comfort is investigated at length with a view to determining methods of measurement of the two classes of vehicle vibrations that affect the riding qualities of a car, so that suitable springs can be designed to overcome them. The underlying principles of the seismograph are utilized in designing a specialized form of this instrument for measuring vehicle vibrations, the general design considerations are stated and a detailed description is given. This is followed by an explanation of the methods used in analyzing the curves obtained, thus making possible a standardized measurement of riding comfort. The factors determining riding comfort are then analyzed in connection with spring-development work, the most important are summarized and the preliminary experimental results of those directly determined by the seismograph are outlined.

The author advocates the use of the fragile aluminum crankcase as a spacer, running crankshaft bearing bolts clear through the crankcase and the cylinder base, so tieing the bearings firmly to the castiron cylinder-block and using the through-bolts also as holding-down studs for the cylinders. The results of experiments on six-cylinder engines with reference to the satisfactory utilization of engine fuel now on the market are then presented. The problem is how to carry the fuel mixture in a proper gaseous state from the carbureter into the cylinder without having the fuel deposited out meanwhile. The power developed at engine speeds of 400 to 2800 r.p.m., with and without hot air applied to the carbureter, is tabulated, the proper location of the intake manifold is discussed, and the necessary features of a satisfactory engine to utilize present-day fuel are summarized.

The author proposes to determine what features of spark-plug construction cause preignition and how this preignition manifests itself. To this end observed conditions on an Hispano-Suiza aviation engine following 4 hr. of an intended 6-hr. run are reported, with supplementary tests and observations. This resulted in experiments made to determine the cause of preignition, using spark-plugs constructed so that different features of their design were exaggerated. Illustrations of these plugs are shown and the results obtained from their tests are described. The different observed peculiarities are then stated, analyzed and compared with normal spark-plug performance. The experiments serve as a means of identification of special forms of preignition and as an indication of the abnormally high temperatures to which valves and combustion-chamber walls are thus subjected.