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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.

The author describes the progress of the work of artillery motorization in the year 1920, beginning this with a statement of the recommendations made by the Westervelt Board, appointed by the War Department to make a study of the subject, for the development of track-laying equipment, the use of wheeled trailers on which the track laying materiel could be loaded and towed over good roads by trucks, and in regard to the possibility of incorporating trailer wheels in the track-laying vehicles themselves. The various types of materiel constructed during 1920 are illustrated, described and commented upon, inclusive of heavy tractors, supply and maintenance equipment, gun-mounts and tanks. It is stated that the recommendations of the Westervelt Board will be the basis of armament development for some time to come.

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.

This paper is illuminative and affords an opportunity for better comprehension of the remarkable progress and accomplishment made in Europe along the lines of commercial aviation. Reviewing the present European routes now in regular or partial operation, the author stresses the essentialness of the attitude of the press in general being favorable if commercial aviation is to become wholly successful. The airship appears most practical for long-distance service, to the author, and he mentions the possibility of towns and cities growing up around “air ports.” The cost of airship travel is specified, although it is difficult to figure costs and necessary charges because so few data on the depreciation of equipment are available. Regarding successful operation, much depends upon the efficiency of the ground personnel and organization.

The author gives an outline of the fundamentals and divides the subject into a discussion of what aerial transportation facilities we have at present and what should be considered for the future, stating that the inventors must determine how far they can go in providing equipment. The first question regarding new equipment is, “Will it work?” The next, “Is it safe?” Safety is described as being purely relative, the statement being made that there is no such thing as absolute safety. There is no need to expect danger. We must have both speed and safety and making aerial equipment safe is well worthwhile, no matter at what expense of money and effort. As to whether commercial aviation can be made to pay, economically and so far as society as a whole is concerned, this is a relative question depending upon the length of haul and the cost per mile. Charts are shown and methods of obtaining basic costs described, together with formulas and coefficients so obtained.

The author brings to attention very emphatically the responsibility of the automotive industry for some things besides the actual building and selling of motor cars. The progress of civilization can be measured very largely by advances in means of communication. The transfer of messages by wire and wireless has made wonderful advances of a fundamental nature in recent years, but the transportation of commodities from place to place has not made such strides. The automotive industry has been concerned mostly with the actual development and production of the motor car and, as an industry, has stopped there without developing those allied activities which are vital to the long-time success of the business. The railroads afford a good example to follow in principle.

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.

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.

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.

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 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.

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 comparatively slow introduction of mechanical power for farm operations has been a surprise and a disappointment to many. It is easily understandable why the deficient machines failed to sell but not so clear why really efficient outfits failed to make greater headway. No one can make a thorough study of the existing situation and conclude that any or all of the reasons given are even in a large part responsible for the slowness in adopting the tractor more generally on the farms; it is obvious that there are other strong influences. Most of these are connected with the farm business itself and, by considering the matter in relation to the individual farmer rather than farmers as a class, these influences become more clear.

An analysis of japanning practice as a systematized industrial operation is presented as the result of an investigation. The nature of japans is discussed and an outline given of how the apparently contradictory requirements that japans must be weatherproof, somewhat flexible, sufficiently thick to be lasting, possess enough hardness to prevent excessive scratching under ordinary service conditions and take on a brilliant finish, can be fulfilled in an ordinary industrial plant without undue expenditure, so as to accomplish the original and primary objects of applying a finish to metal parts to prevent them from too great deterioration and supply a pleasing appearance to the finished product. Adequate provision for securing a uniform product is essential. The details of this are discussed. Three ways of applying japan are explained. The considerations involved in cleaning the metal and baking japan are enumerated at some length and the methods are 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.