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Technical Paper

BURNING KEROSENE IN TRACTOR ENGINES

1917-01-01
170031
The author states as his object a review of what has been done and what must be done to make tractors successful in operating on low-grade fuels, especially kerosene. He takes up in order the four principal methods in common use of applying heat to vaporize kerosene, pointing out the advantages and disadvantages of each method and of its modifications. The author then cites various experiments with different types of carbureters in burning kerosene, drawing at length upon his own experience in this connection. He cites difficulties with gas distribution, manifold condensation, pistons and spark-plugs and points out that carbureter design is inseparable from considerations of tractor engine and manifold design. That better progress has not been made in the past in developing kerosene-burning tractor engines is stated to be largely owing to the fact that there has not been sufficient cooperation between engine and carbureter manufacturers.
Technical Paper

SOME PROBLEMS IN AIRPLANE CONSTRUCTION

1917-01-01
170001
The authors advance for discussion some important problems in the construction of airplanes for military use in this country. The functions of military airplanes designed for strategical and tactical reconnaissance, control of artillery fire and for pursuit are outlined. Problems in construction with reference to the two-propeller system, methods of reducing vibration, application of starting motors, details of the gasoline supply-system, metal construction for airplanes, flexible piping, desirable characteristics of mufflers, shock absorbers, landing gear, fire safety-devices, control of cooling-water temperature, variable camber wings, variable pitch propellers and propeller stresses, are all given consideration. The paper is concluded with suggestions for improvement in design relating to the use of bearing shims, the rigidity of crankcase castings, interchangeability of parts and better detail construction in the oiling, ignition, fuel supply and cooling systems.
Technical Paper

SOME ESSENTIAL FEATURES OF HIGH SPEED ENGINES

1917-01-01
170004
The author outlines methods for producing high-speed engines with high mean effective pressure and gives data resulting from several years' experimental work. He discusses the desirable stroke-bore ratios; valve area, weight, dimensions, location and timing; compression ratios; ignition requirements; and the location and means for operating camshafts and other valve-actuating mechanism. Data are given regarding the best material and dimensions for pistons and the desirable number of rings. The physical characteristics of alloy steel desirable for use in connecting-rods are mentioned. Similar data, including dimensions and factors controlling the construction of the crankshaft and its bearings are included. The relation of the inertia stresses set up by reciprocating parts to those due to the explosion and compression pressure on the piston head is indicated, and the maximum total stress deduced.
Technical Paper

DYNAMIC BALANCING OF ROTATING PARTS

1917-01-01
170005
The author points out the necessity of obtaining dynamic or running balance of rotating parts, especially in automobile-engine construction. He discusses the manifestations of the lack of static and running balance, such as vibration and high bearing pressures. Formulas are supplied for calculating bending moments and centrifugal forces in a crankshaft that is out of balance. Methods for obtaining static balance are described and the possible conditions existing after static balance is obtained are treated, with especial reference to the existence of one or more couples. Descriptions are given of two representative machines that are used to locate couples and correct for them. The principles of operation are made clear and advantages and disadvantages of each type are brought out fully.
Technical Paper

PROBLEMS IN IGNITION DEVELOPMENT

1917-01-01
170053
The author discusses in this paper a few of the problems involved in the design of ignition equipment. Some of these problems have been solved and some remain to be solved. The early history of the development of ignition apparatus is traced, reference being made to the vibrating coil type of ignition operated by dry cells or storage batteries, various types of magneto and dual-magneto systems, and combined generator and storage battery systems. The balance of the paper refers more particularly to batteries and ignition proper. The two types of battery ignition, open-circuit and closed-circuit, are described and the current characteristics of each are shown graphically by means of curves. Some of the problems encountered in the development of present battery systems are next considered and such topics as reduction of inertia in the contact-arm, overcoming harmonic vibration, advantages of one-piece cams and the function and design of the condenser are treated in detail.
Technical Paper

DESIGN OF AN ENDURING TRACTOR

1917-01-01
170049
After a few general introductory remarks the author outlines the operating requirements for tractors, and takes up the matter of the proper sizes of tractors, stated in horsepowers per given number of plows. The use of lower-grade fuels, value of water in the engine, cylinder construction, methods of lubrication and design of drive-wheels are the subjects covered by the balance of the paper.
Technical Paper

SOLVING THE GASOLINE PROBLEM

1917-01-01
170047
The author first compares mineral oils with certain other liquids in order to point out clearly certain of their characteristics. He then shows the economic benefits that would result from making more of the crude available for use as fuels. He discusses such topics as cracking methods in use, advantages of dry gas, initial flame propagation, gas producers, hot mixtures, wet mixtures and difficulties of correcting existing engines. He concludes by proposing as a solution of the gasoline problem the more general use of superheated homogeneous fixed dry gases made in vaporizing devices independent of engine cylinders, and outlines means for attaining this end. Performance data covering the use of mixtures of kerosene and gasoline on several cars are included in a table, and several charts throughout the paper illustrate many of the topics discussed.
Technical Paper

METROPOLITAN SECTION PAPERS TREATMENT OF HYDROCARBON FUELS

1917-01-01
170046
The author states that the objects of the paper are to define and trace the development of the various processes of carburetion, and to offer such suggestions along these lines as may assist the investigator in developing motorboats, automobiles and self-contained unit motor cars for railway purposes. The surface carburetor is mentioned chiefly as of historic interest. In considering the jet carbureter the author discusses the proportion of gas desired, the effect of the varying inertia of the air and the liquid gasoline and the breaking up of the combustible needed. Following sections review the devices for using kerosene, such as gasoline jet carbureters to which heat is applied, devices of the fixed gas type, the introduction of combustible directly into the cylinder, forcing combustible directly upon a hot surface in the cylinder and devices which raise the combustible to the boiling point.
Technical Paper

PROBLEMS OF CRANKSHAFT DESIGN

1917-01-01
170040
The forces necessary to induce and maintain gasoline engine speeds of 3000 r.p.m. or faster, as well as other forces closely associated with high speeds, are numerous. The author has, however, confined his discussion to the three most important groups of forces upon which, in the main, the smooth running and the life of an engine depend. The different component forces were determined in respect to two engines of equal capacity for twenty-four crank positions, uniformly spaced at intervals of 30 degrees, which constitutes two revolutions and one complete cycle in the case of four-stroke cycle engines. Medium-sized six and twelve-cylinder engines were chosen for investigation. Corresponding components were combined as resultant forces and graphically represented in magnitude and direction. Several such characteristic diagrams of the resultant forces acting upon crankpins and main bearings of the two engines investigated are reproduced throughout the paper.
Technical Paper

AVIATION ENGINE DEVELOPMENT

1917-01-01
170042
This paper first traces the early development of aviation engines in various countries. The six-cylinder Mercedes, V-type twelve-cylinder Renault, and six-cylinder Benz engines are then described in detail and illustrated. Various types of Sunbeam, Curtiss, and Austro-Daimler are also described. The effect of offset crankshafts, as employed on the Benz and Austro-Daimler engines, is illustrated by pressure and inertia diagrams and by textual description. The paper concludes with a section on the requirements as to size of aviation engines, four curves showing the changing conditions which affect the engine size requirements. These curves relate to variations of temperature, air density, engine speed, airplane speed and compression ratio required to compensate for decrease in air density, all as related to varying altitude.
Technical Paper

PROBLEMS IN HIGH-SPEED ENGINE DESIGN

1916-01-01
160023
The author outlines in a general way the relation of car performance to modern engine development. He considers particularly weight reduction and torque performance of high-speed engines, giving the undesirable characteristics attending the increased torque range gained by higher speed. He next discusses the relation of torque to total car weight, to acceleration and to hill-climbing ability and suggests a method of determining the value of a car in terms of its performance ability. The author holds incorrect those systems in which the amount of lubrication is in proportion to speed only; and in which oil for crankshaft and crankpin bearings must cool as well as lubricate them. He shows a system designed to solve these oiling problems. Static, running and distortion balance of a rotating mass are defined by the author, who shows how they apply to a large number of types of crankshafts.
Technical Paper

RECENT AEROPLANE-ENGINE DEVELOPMENTS

1916-01-01
160025
The author gives a brief review of developments during the past year in the construction of aeroplanes, particularly as affected by the European War. He takes as an example the Renault twelve-cylinder engine, citing the respects in which the present differs from previous models. Such factors as the changes in cooling systems, method of drive, valve construction and starting devices are considered. The requirements of aeroplane engines, such as constant service, high speeds (of aeroplanes) and stream-line form of engines and radiators, are outlined. Propeller requirements are dealt with at length, curves being given by which the efficiency and diameter of the propeller can be obtained. In conclusion a number of different engine installations are illustrated and compared.
Technical Paper

PNEUMATIC TIRE AND RIM SITUATION

1916-01-01
160029
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.
Technical Paper

MECHANICAL TRANSPORT MOBILIZATION

1916-01-01
160033
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.
Technical Paper

FACTORS IN UNIVERSAL JOINT DESIGN

1916-01-01
160036
The author considers the effects of velocity variation on the operation of a car and states that this variation is absorbed mainly by the flywheel. A formula is given for calculating the pressure on universal bearings. Various methods of protecting and lubricating joints are described. A number of European types of joints are illustrated. A much larger number of types of joints are used abroad in-asmuch as each maker usually makes his own design instead of purchasing it from a specialist as is the usual practice in this country. In conclusion the paper describes types of joints using flexible material, such as leather or spring steel.
Technical Paper

ELECTRIC TRANSMISSION ON OWEN CARS

1916-01-01
160041
This paper contains a brief description of the Entz electric transmission. Wiring connections are given of the several speeds, for electric braking, for starting the engine and for charging the battery. The statement is made that the electric transmission eliminates and does the work of the friction clutch, the clutch pedal, the transmission gears, the flywheel and separate starting and lighting systems.
Technical Paper

ENGINES OF THE AIR

1916-01-01
160039
After a brief consideration of airplane-engine practice in France, England and Germany, the author outlines the problems encountered in designing a twelve-cylinder aviation engine. He explains at some length the difficulties in determining the connection between propeller and engine and shows why valve-in-head location was chosen. Such features of engine design as the mounting of carbureter and exhaust pipes, methods of fuel and lubricant supply and details involved in selecting the lighting, starting and ignition equipment are considered.
Technical Paper

FOUR-CYLINDER ENGINES OF TO-DAY*

1916-01-01
160043
The paper gives the value of certain factors in engine design that are good practice and uses these values to calculate the horsepower of a four-cylinder engine. The author holds that the deciding factor in comparing four-cylinder engines with those of the same displacement but with a greater number of cylinders, is the thermal efficiency. Both the cooling medium and the mechanical losses increase in proportion to the number of cylinders. He suggests in closing, that the demand for power output beyond the possibilities of four cylinders must be met by the use of a greater number.
Technical Paper

FIELD OF FOUR-CYLINDER ENGINES*

1916-01-01
160042
The author confines his discussion to engines used on pleasure cars, inasmuch as practically all commercial vehicles use the four-cylinder type. The performance expected of their cars by automobile owners is outlined, particularly as regards performance, durability and maintenance cost. In-asmuch as the horsepower required is often determined by the acceleration demanded, the argument in favor of four-cylinder engines is based mainly on a comparison of its acceleration performance with those of engines having a larger number of cylinders. A number of acceleration curves are given for these engines. The paper next considers smoothness of operation at low, medium and high running speeds, asserting that the decrease in inertia forces due to lighter reciprocating parts has made it possible to increase the speed and thus reduce remarkably the vibration of the four-cylinder engine.
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