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Two distinct problems are involved in fuel research work, multi-cylinder distribution and the chemical constitution of the fuel mixture after it enters an engine cylinder. In discussing elementary combustion, the author refers to the components of the energy of combustion as gravitational, kinetic and barometric, and elaborates his theme with the aid of diagrams and charts showing normal and abnormal combustion. After emphasizing the necessity of theorizing at some length, anti-knock substances are discussed, inclusive of substances apparently dissimilar that have the same chemical constituents. The ignition point and fuel utilization are treated, followed by comments upon fuel studies that have been made, with accompanying indicator-cards. The future objectives of fuel research are outlined as being along lines of physical and of thermo-chemistry, the simple laws of elementary physics, and cooperation with the producers and refiners of the fuel.

The data given in this paper were obtained from an investigation by the Bureau of Mines in cooperation with the New York and New Jersey State Bridge and Tunnel Commissioners to determine the average amount and composition of the exhaust gases from motor vehicles under operating conditions similar to those that will prevail in the Hudson River Vehicular Tunnel. A comprehensive set of road tests upon 101 motor vehicles including representative types of passenger cars and trucks was conducted, covering both winter and summer operating conditions. The cars tested were taken at random from those offered by private individuals, corporations and automobile dealers, and the tests were made without any change in carbureter or other adjustments. The results can therefore be taken as representative of motor vehicles as they are actually being operated on the streets at the various speeds and on grades that will prevail in the tunnel.

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.

Stating that the knowledge now available does not permit an exact scientific definition of flame and giving the reasons, in this paper the author regards flames as gases rendered temporarily visible by reason of chemical action, discusses their physical rather than their chemical aspects and, unless otherwise indicated, refers to the flames of common gasoline and kerosene only. To gain a reasonably clear understanding of the requirements and characteristics of the different kinds of flame, it is necessary to begin with a study of atoms and molecules. The author therefore discusses the present atomic theory, the shape of the atom and molecular structure, and follows this with a lengthy detailed description of the beginning of combustion. The requirements and characteristics of the inoffensive variety of combustion are considered next and nine specific remedies are given for use in accomplishing the burning of heavy fuels with a blue flame in present engines.

The paper analyzes and states the factors affecting the power requirements of cars as rubber-tired vehicles of transportation over roads and the factors affecting the amount of power supplied the car as fuel to produce at the road the power required for transportation. Quantitative values are given wherever possible to indicate the present knowledge of the relation between the factors involved, and the text is interspersed with numerous references, tables, charts and diagrams. Among other important factors specifically discussed are mixing and vaporization, charge quantity control, the heat of combustion, gas-pressure, transformation loss and power transmission efficiency. Six appendices contributed by other associates of the Bureau of Standards are included.

In discussing the probable trend of aeronautical powerplant development and subsequent to a brief survey of the present situation, the authors review the evolution of various engine types and analyze the effect of their characteristics on airplane performance, considering also the proper installation of airplane powerplants. The problem now confronting the industry is one of establishing standard types for the powerplants required by each service and setting up reasonable power requirements for each unit. For each service, factors must be developed to permit the making of correct comparisons of the performance of the different engines. The future types of engine are considered at some length and special reference is made to radial engines. Curves and tabular data accompany the discussion of variations in engine elements and the characteristics of a high-speed airplane are treated in a similar manner.

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.

Emphasis is placed upon the propriety of applying the term “research” only to such lines of investigation as are capable of yielding general results that can be utilized by other than the original observers. The distinction between research thus defined and much else that can be classed correctly as research according to its dictionary definition is explained. In stating the purpose and aim of the Research Department of the Society, the divisions of the thought include research personnel requirements, the support of research, the importance of research, problems suitable for research in the industrial, educational and independent laboratories, the general research program and the avoidance of duplication of research work.

This paper is a collection of notes gathered from investigation of the subject in the literature on the development of internal-combustion engines and memoranda set down during a long series of tests. The paper includes a discussion of the physical and chemical aspects of the subject and sets forth a working theory that has proved of value. Several methods of measuring turbulence are stated. After outlining the history of the subject and giving references, the effect of turbulence on flame propagation is discussed at length and illustrated by diagrams. Two methods of producing turbulence are then copiously illustrated and described, inclusive of seven diagrams showing characteristic turbulence in typical cylinders. Following the description of the methods of measuring turbulence, the effects of turbulence in performance are summarized under 10 specific divisions.

First reviewing the history of the progressive insufficiency of the supply of highly volatile internal-combustion engine fuels and the early efforts made to overcome this by applying heat to produce rapid vaporization, the author gives an outline of the methods already found valuable in offsetting the rising boiling points of engine fuels and states the resulting three-fold problem now confronting the automotive industry. The tendency to subordinate efficient vaporization to the attainment of maximum volumetric efficiency is criticised at some length and the volatility of fuel is discussed in detail, with reference to characteristic distillation, time of evaporation and distillation-temperature curves which are analyzed. Heating devices are then divided into four classes and described, consideration then being given to fuel losses outside the engine.

The author first considers the style and arrangement of the seats, the position of the rear axle as affecting the rear kick-up in the chassis frame, and the position of the rear wheels as determining the distance from the back of the front seat to a point where the curve of the rear fender cuts across the top edge of the chassis frame. The location of the driver's seat and of the steering-wheel are next considered, the discussion then passing to the requirements that affect the height of the body, the width of the rear seat, and the general shape. The evolution of the windshield is reviewed and present practice stated. Structural changes are then considered in relation to the artistic requirements, as regards the various effects obtained by varying the size or location of such details as windows, doors, moldings, panels, pillars, belt lines, etc., and the general lines necessary to produce an effect in keeping with the character of the car.

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.

Flame propagation has received much attention, but few results directly applicable to operating conditions have been obtained. The paper describes a method devised for measuring the rate of flame propagation in gaseous mixtures and some experiments made to coordinate the phenomena with the important factors entering into engine operation; it depends upon the fact that bodies at a high temperature ionize the space about them, the bodies being either inert substances or burning gases. Experiments were made which showed that across a spark-gap in an atmosphere of compressed gas, as in an engine cylinder, a potential difference can be maintained which is just below the breakdown potential in the compressed gas before ignition but which is sufficient to arc the gap after ignition has taken place and the flame has supplied ionization. These experiments and the recording of the results photographically are described.

The indicator was an important factor in the early development of the internal-combustion engine when engine speeds were low, but on high-speed engines such indicators were unable to reliably reproduce records because of the inertia effects of the moving part of the pressure element. The first need is for a purely qualitative indicator of the so-called optical type, to secure a complete and instantaneous mental picture of the pressure events of the cycle; the second need is for a purely quantitative instrument for obtaining an exact record of pressures. The common requirements for both are that the indicator timing shall correctly follow the positions of the crank and that the pressure recorded shall agree with the pressures developed within the combustion space. Following a discussion of these requirements, the author then describes the demonstration made of two high-speed indicators, inclusive of various illustrations that show the apparatus, and comments upon its performance.

It is stated that the general performance of the steam-propelled automobile has never been equalled by that of the most highly-developed multiple-cylinder gasoline cars and that it is significant that no innovation in the gasoline car has yet been able to give steam-car performance. This led to an effort to remove the troublesome features of the steam car, rather than to complicate the gasoline car further by attempting to make it duplicate steam-car performance. The paper describes in detail the steam automotive system developed by the author and E. C. Newcomb, including the boiler, the combustion system and its control, the engine and the condensing system.

A tendency exists in most shops to assume that brazed joints cannot be successfully heat-treated. As a consequence, many fittings used in aircraft work and assembled by brazing smaller parts together are finished and installed without being heat-treated after the brazing operation. This practice causes parts to be used that not only do not develop the available strength of the material, but which are in some cases, under internal stress due to the heating in the brazing operation. Recent experiments made at the Naval Aircraft Factory show that the assumption mentioned is entirely erroneous. The author considers this matter with a view to specifying the use of steels and brazing spelters which will permit the subsequent or perhaps the simultaneous heat-treatment of the parts.

Motorization, as developed during the war, is stated as the greatest single advance in military engineering since the fourteenth century. Excepting about 66 per cent of the 77-mm. guns in the combat division, all mobile weapons of the United States artillery are motorized and complete motorization has been approved. The history of artillery motorization is sketched and a tabulation given of the general mechanical development in artillery motor equipment to May, 1919. Caterpillar vehicle characteristics are next considered in detail, followed by ten specifically stated problems of design which are then discussed. Five primary factors affecting quantity production, successful construction and effective design, in applying the caterpillar tractor to military purposes, are then stated and commented upon. A table shows specifications of engines used by the Ordnance Department and three general specifications for replacing present engine equipment are made.

The free, resilient, self-expanding, one-piece piston-ring is a product of strictly modern times. It belongs to the internal-combustion engine principally, although it is applicable to steam engines, air-compressors and pumps. Its present high state of perfection has been made possible only by the first-class material now available and the use of machine tools of precision. The author outlines the history of the gradual evolution of the modern piston-ring from the former piston-packing, giving illustrations, shows and comments upon the early types of steam pistons and then discusses piston-ring design. Piston-ring friction, the difficulties of producing rings that fit the cylinder perfectly and the shape of rings necessary to obtain approximately uniform radial pressure against the cylinder wall are considered at some length and illustrated by diagrams.