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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 uses some analogies of mechanical things to illustrate the underlying facts that must be considered in connection with electrical ingition, the first being that of an automobile starting under the influence of a constant force, which is analogous mechanically to the old touch-spark ignition circuit in that the velocity of the automobile corresponds with the velocity or speed at which the electricity is moving through the circuit. In similar manner the analogy is extended to include car acceleration and its acquirement of a certain store of energy as an illustration of electrical-energy storage as the current through an induction-coil is increased; and further analogies are made, numerous diagrams being presented. Battery and magneto-ignition similarities are treated in a similar way, short and long sparks are discussed pro and con and spark lag is considered in general terms.

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.

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.

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 purpose of the tests described was to subject various models of truck to shocks far in excess of anything likely to be encountered in actual service, to study the effect of different spring and tire equipment on impact and the effect of unsprung weight upon road impact, as well as the effect of varying speed on these impacts. A series of “jumping tests” for motor trucks was conducted and a new system of motion pictures, capable of being afterward slowed down for analysis, was used to record the results. Trucks were run at speeds of from 15 to 18 m.p.h. along a straightaway course and over a sharp incline. The trucks sprang into the air and struck the ground as from a vertical drop of several feet. The apparatus and the five trucks used are described fully, the data obtained and the method of computing results are presented, and the analysis and conclusions which follow are sufficiently detailed to afford much constructive information on this subject.

The early wheels merely rolled, carried weight and resisted side strains; later they were called upon to transmit braking forces and still later the driving force. Prior to the automobile, wire wheels were not called upon to support much weight and the usual type was that used for bicycles. When automobiles were first built, bicycle-type wire-wheels were employed and used until the demand for larger wheels presented unsurmountable obstacles. From that time a development was in progress in this country and in England that resulted in the triple-spoke wire-wheel which has grown in popularity since 1912. The different types of wheels are discussed and the advantages and disadvantages of wire wheels stated; three diagrams are shown. As the wire wheel is a “suspension” wheel, the car weight is hung or “cradled” from scores of resilient, flexible spokes, and the pull is always on three-quarters of the spokes.

These experiences relate to the Akron-Boston motor-truck express, established in April, 1917, the Wingfoot Highway Express between Akron and Cleveland which began active operations in January, 1919, and the Goodyear Heights motor omnibuses for passenger service in Akron inaugurated in December, 1917. The preliminary difficulties are reviewed and a mass of specific data regarding construction, operation, maintenance and costs is presented in textual and tabular form, the latter including a summary of pneumatic-tire accomplishment, comparative truck efficiency, an operating summary for six months, the operating cost and efficiency of two 3½-ton twin trucks running on pneumatic and on solid tires respectively, and an operative summary of the Goodyear Heights buses.

Although disc wheels have not been produced in such great quantities as some of the other types, they have advanced far enough in practical application to demonstrate their possibilities and fundamental correctness. Distinction should be made between the wheel itself, the single-taper dished disc and other features such as tire, rim and hub applications. Single-taper dished-disc wheels were developed in France and in this country at about the same time but, on account of the variation in European and American tire practice, the resultant wheels took different forms. The author describes these forms and comments upon them, the argument being favorable to the single-taper disc, and the statement is made that, given the data as to the service expected, the weight and power of the car, the single-disc wheel will compare favorably with any other type, since, when properly designed, the strains are diffused over the entire surface.

A brief outline of the elementary principles of the operation of jump-spark ignition systems is given preliminarily to the discussion of the advantages of battery-type systems, and four vital elements in a jump-spark ignition system are stated. A diagram is shown and explained of an hydraulic analogy, followed by a discussion of oscillating voltage and oscillograms of what occurs in the primary circuit of an ignition system when the secondary is disconnected. The subjects of spark-plug gaps and current values receive considerable attention and similar treatment is accorded magneto speeds and spark polarity, numerous oscillograms accompanying the text. The effects of magneto and of battery ignition on engine power are stated and commented upon and this is followed by a lengthy comparison of battery and magneto ignition, illustrated with charts.

A discussion of the advantages of magneto ignition resolves itself into a comparison of magneto and battery-ignition systems, resembling early discussions of the relative merits of the direct and the alternating-current electric systems; both are in existence and fulfilling their respective parts. After stating that ignition is closely related to carburetion and generalizing on the subject of ignition, the author discusses the fundamentals of ignition systems at length, presenting numerous diagrams, and passes to somewhat detailed consideration of comparative spark values, using illustrations. Storage batteries and auxiliary devices receive due attention next and numerous characteristic curves of battery and magneto ignition are shown. Impulse couplings are advantageous in starting large truck and tractor engines, which generally use magnetos; these are described.

Three distinct types of wheel equipment are best able to meet conditions in the field; the pyramid lug, the spade lug and the angle-iron cleat. The author mentions the merits of each type of lug, discusses slippage and states that no one kind of wheel equipment can be recommended as a universal type.

The paper surveys the economic and engineering aspects of the automotive industry, so that engineers can align themselves with its future development. Better performance and longer life due to improved design and materials distinguish the 1920 car from its predecessors. One of the healthiest signs in the industry is the uniform determination of practically every manufacturer to improve the quality of his product. The designer has been forced to extend himself in getting the highest possible output from the smallest possible units. This trend is very noticeable. Conditions relating to prices, the return to peace-time production, the potential demand for cars and the present supply, and the probable improvements in cars are then reviewed, the thought then passing to a somewhat detailed discussion of detachable-head engines.

After stressing the importance of transportation, the possible uses of the motor truck are considered. The increased cushioning and traction obtained from pneumatic truck tires accomplish faster transportation, economy of operation, less depreciation of fragile load, easier riding, less depreciation of roads and lighter-weight trucks. These six advantages are then discussed separately and various data to substantiate the claims made are presented. Following detailed consideration of transportation and operation economies, and depreciation of loads and roads, the practicability of pneumatic tires is elaborated, and wheels, rims and tire-accessory questions are studied. The four main factors bearing upon truck design for pneumatic tires are stated and discussed; emergency equipment for tire repair is outlined and a new six-wheel pneumatic-tired truck is described.

Stating the desirability of reducing unsprung weight in motor vehicles as a recognized fact and that 75 of 100 engineers interviewed favor such reduction, the particular advantages resulting are given as improved riding qualities, economy in tire wear and better acceleration. Mathematical deductions to establish the most desirable ratio of sprung to unsprung weight are not attempted, the intention being rather to state the reasons favoring lighter wheels and axles. Unsprung weight effects depend primarily upon the ratio of sprung to unsprung weight. No data determining the most desirable ratio are available, but an investigation of the proportional weight of the unsprung and sprung parts of good-riding-quality automobiles showed it to be about 1 to 3. By constructing the wheels and the axles of light metal it is possible to maintain such a ratio, assure good riding qualities and reduce the total weight.

The discussion is largely in regard to the ability of a truck to deliver merchandise economically under a given set of external conditions. The matter of truck tire equipment is reviewed in the light of recent experiences of many operators and service men. The general functions of tires, securing traction, cushioning the mechanism and the load and protecting the road, are elaborated and six primary and seven secondary reasons given for the use of pneumatic tires on trucks within the debatable field of 1½ to 3½-ton capacity. The deciding factors in tire choice, those affecting time and those affecting cost, are stated and commented upon, the discussion next being focused on how tires affect these factors. Considerations relating to both truck and tire repairs are then reviewed.

In investigating the forces that tend to break up and destroy roads, the most destructive of these being that of impact, the United States Bureau of Public Roads devised a method of receiving the impact of a truck on a small copper cylinder and determining its amount by measuring the deformation of the cylinder. The impact values are largely dependent upon the type and construction of the truck. Unsprung weights have a great influence upon the impact value of the blow on the road surface and a reverse influence upon the body of the truck; these effects are in two different directions. The present aim of the Bureau is to investigate this impact and the effect of the unsprung weight on the road. Most of the tests have been made on solid tires, a few have been made on worn solid tires and some on pneumatic tires. The Bureau intends to elaborate all of these tests, including different types of pneumatic tire, different unsprung weights and special wheels, such as cushion or spring wheels.

The paper relates to some of the methods and apparatus which can be used to advantage in large-scale farming operations. The laying out of a production program, the transportation of men and supplies, special implements for raw-land preparation, tractor dynamometers, large tractors, special plowing and tilling implements, four-wheel-drive tractors and road haulage are discussed. An operation chart applying to an area of 40,000 acres is first presented and analyzed. Regarding hours of operation, the author maintains that with a suitable organization and proper selection of motive power and implements, tractors can be kept in motion 20 hr. per day and gives a time-table. Consideration is then given in some detail to the problems of electric lighting, the implements used in raw-land preparation, the power required for various operations, types of tractor construction, plowing and harrowing, harvesting, hauling and tractor-train schedules, the whole being copiously illustrated.