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The authors enumerate some of the questions that are involved and, after outlining a previous paper on the subject of plows, analyze these questions in part by the aid of diagrams and applied mathematics. Comparative draft data are presented in tabular form and commented upon, as well as comparative hitch-length data. Tractor reactions are explained and discussed in some detail in a similar manner, special attention being given to the reactions on a slope and up-hill. The reactions on cross-furrow slopes are considered, comparisons being made between two tractors that were reported upon in the University of Nebraska tests. The factors involving tractor stability and resistance against overturn are analyzed. The authors state that the analysis presents a definite method of attack for the more correct solution of the proper hitching-point, as well as being a study relating to lug design.

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 Chicago Service Meeting paper relates specifically to the type of garage equipment that is used to handle the motor vehicle in preparation for its repair. The devices illustrated and described are those designed to bring in disabled cars, and include wrecking cranes and supplementary axle trucks; portable cranes and jacks on casters for handling cars in a garage; presses, tire-changing equipment and wheel alignment devices; engine and axle stands; and miscellaneous minor apparatus. The different factors mentioned emphasize the great need of standardization. The thought is not to do away with a car's individuality, but to construct all parts so that cars may have efficient service to the highest degree through the agency of every serviceman.

The paper is an exposition of the theoretical analysis made by the author of the experimental work of Woodbury, Canby and Lewis, on the Nature of Flame Movement in a Closed Cylinder, the results of which were published in THE TRANSACTIONS for the first half of 1921. No experimental evidence is presented by the author that has not been derived previously by other investigators. The relation of pressure to flame travel is derived first, the relation of mass burned is considered and a displacement diagram constructed, described and analyzed. The break of the flame-front curve, called the “point of arrest,” enters prominently into the discussion and computations; the pressure in the flame-front is studied; the reaction-velocities are calculated; and general comments are made.

That all of the variable factors of automobile friction-losses such as the quantity and viscosity of lubricants, the efficiency of worm-gearing and part-load Modifications are not appreciated, is indicated by an examination of the literature on this subject which reveals a lack of necessary data. Experiments to determine the mechanical losses, including all friction losses between the working gases in the engine and the driving-wheels of the vehicle, are described and supplementary data are included from Professor Lockwood's experiments at Yale. Three distinct possibilities for increasing the fuel economy of a motor vehicle are specified and enlarged upon, gearset experiments to secure and develop data for a four-speed gearset being then described and commented upon at length; photographs and charts illustrative of the equipment used and the resultant data are included.

The author outlines the history of the Air-Mail Service and states that the recent policy has been to carry out the intent of the Congress, to align the service with the desire of the administration for economy and to discontinue too rapid expansion. After a description of the routes and divisions and a listing of the present landing-fields and radio stations, the present equipment is outlined and commented upon, tabular and statistical data being presented. The discussion covers the organization and performance of the service, the casualties, the cost of operation and the policy governing future plans.

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.

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.

Vibrations of several kinds can occur in crankshafts, but the principal ones are transverse and torsional; the paper deals entirely with the latter. A simple case of torsional vibration is considered first and the principles are applied to the torsional vibration of a shaft, the argument being carried forward at some length. A discussion of critical speeds follows and this is supplemented by a lengthy mathematical analysis, inclusive of diagrams. Calculations were made to determine the period of the shafting of United States submarines S4 to S13 and these are described. The three cases investigated include the charging condition when the engine is driving the dynamo, the after clutch being disconnected; the surface condition, when the engine drives the propeller; and the submerged condition, when the motors drive the propeller, the forward clutch being disconnected. Calculations were made also with a Sperry magnetic clutch substituted for the usual flywheel and clutch.

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.

For many years plywood has been used for such automobile parts as roofs and dash and instrument-boards, but it was not until the closing of the European war that the extent to which this material was used in automobile construction greatly increased. The sudden requirement of airplanes created a large demand for plywood which would withstand the severest weather conditions. Glues were perfected that enabled plywood to withstand 8 hr. of boiling or 10 days of soaking in water without separation of the plies. Plywood as an engineering material is discussed. It is then compared in considerable detail with ordinary boards and also with metals and pulp boards, statistics and illustrations being given. The molding of plywood is considered with especial reference to employing plywood for surfaces having compound curvatures, and the limiting factors in the use of plywood for this purpose are mentioned.

MEXICO achieved second place among the petroleum-producing nations of the world in 1918. This position will not soon be relinquished, judging from the study made by the author of the two general regions from which petroleum has thus far come. The Petroleum Commission of the Mexican Government has issued statistics covering the production by years since the industry started. It is confidently hoped that future production will continue, as indicated, to stop the gap, constantly increasing and critical, between production and consumption in the United States. A section of the paper is devoted to the export trade, especially with this country, which furnishes the nearest great market.

BUREAU of Mines refinery statistics for the calendar year 1918 show a production of different types of petroleum fuel products represented by the following approximate figures: Added to this are 3,100,000,000 gal. of crude oil, used as fuel without refining. The statistics do not distinguish the different classes of fuel oils, and the following provisional estimate has been made: Processing or refining costs for the different oils are difficult to estimate and of little significance in determining the selling price, which is controlled by the law of supply and demand. All types in the last list can be used in so-called heavy-oil engines, but the gas oil and light residuum are most desirable in the order given. They are less plentiful than the heavy-residuum type which generally cannot be used without special equipment for preheating. The proportionate yield of gas oil can be increased if a sufficient demand is developed.

The paper opens with a number of quotations from publications issued by the Army War College and showing the bearing of motor transport on a proper military policy for the United States. The author then describes two experimental trips recently made by motor-truck owners near New York in an effort to determine proper motor-transport operating conditions. A statistical summary is given for these two experimental trips. The Army War College has issued in compliance with instructions of the Secretary of War a “Statement of a Proper Military Policy for the United States,” supplemented by a number of pamphlets dealing with particular features of this military policy in considerable detail. In many of these supplementary pamphlets there appears a considerable amount of material bearing upon the subject of motor transport and from them the brief quotations in the following paragraphs are taken.

The author limits his consideration of rear axles to that of the bevel-gear type and takes up the subject under the heads of load-carrying member, gearing, driving-shaft, brakes and materials. Several different forms of cast and pressed axle housings are briefly described. Mention is then made of the axle gearing and data given showing the end thrust for straight-tooth bevel pinions. The methods of supporting pinions and of attaching bevel gears to the differential are discussed. Forms of differentials are considered, several different conventional types being illustrated. The subject of driving shafts is briefly reviewed, as is also that of brakes and brake materials. The author concludes his paper by figures showing the tensile strength, elastic limit and elongation of the metals used in the various parts of the rear axle and also explains some oil-retaining and dust-protecting features of design.

The author starts with the development of the pneumatic tire since its invention by Dunlop in 1888, and proceeds to show why several different types of tire construction are now in use. The merits of the three types of tires, namely, the clincher, straight-side and quick detachable, are discussed as regards energy consumption, traction, total mileage, cost-per-tire-mile, cushioning effect, reliability, ease of applying and service. The conclusions brought out show principally the advantages of the straight-side tire. Statistics are offered to show the trend of the rim situation, and it is pointed out that it is just a question of time when the quick detachable clincher will cease to survive. It had a legitimate place during the development stage, but with the developed straight-side tires giving entire satisfaction, the author holds that there is no excuse for continuing the quick detachable clincher type.

In this paper a computer simulation study on the effects of steering parameters on lateral dynamics of the guideway bus to contribute to a development practice of designing optimum steering control system are dealt with. A stability limit of vehicle lateral motion is analyzed and an emphasis is laid on the effects of moment of inertia of a conventional steering wheel and lateral elasticity of the guide rail which have proven to reduce the critical vehicle speed. It is pointed out conclusively that a normal bus equipped with additional simple guidance equipments can be guided smoothly on a simple guideway at adequately high vehicle speed.