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Viewing 33151 to 33180 of 33251
1933-01-01
Technical Paper
330032
H. M. CRANE
Irritated by statements of some alleged economists to the effect that, except for changes in the appearance of motor-cars, the automobile industry has stood still for the last five years, the author of this paper, who is affectionately regarded as the dean of automobile engineering in this Country, spoke at meetings of the Philadelphia and Metropolitan Sections of the Society on the many car and engine improvements made in recent years. Mr. Crane's remarks, as reported stenographically and embodied in this paper, deal chiefly with engines. He points out that extensive highway improvement and the consequent public demand for higher car speed have forced engineers to design more powerful and more versatile engines without increasing the weight. High-speed engines were of necessity the answer, and these brought the problem of eliminating roughness of operation and preventing transmission of vibration to the chassis.
1933-01-01
Technical Paper
330037
W. R. Jennings
Mr. Jennings describes a test now being considered for determining the point of optimum superheat for lifting iron from a static to a dynamic condition, with tensile strength of alloyed cast iron of 80,000 lb. per sq. in. and of heat-treated iron of 100,000 lb. per sq. in. When this field is entered, increased temperature becomes necessary for consistent results, and a series of tests is being run to discover approximately the temperature at which breakdown of the carbon nucleus occurs. The electric furnace, Mr. Jennings asserts, offers a non-oxidizing and non-contaminating method of melting iron at any desired temperature and allows iron to become high-brow and choosy.
1933-01-01
Technical Paper
330039
W. E. Lay
THIS is Part 1 of a study of air resistance in terms that the automobile engineer can understand without delving deeply into aerodynamics. The study was suggested by the fact that motor-vehicles are now being driven at a speed at which most of the engine power is used to overcome air resistance, although the greater part of this resistance is unnecessary and can be eliminated by correct shaping of the vehicle body. It is a progress report of research just begun. After analyzing car resistance mathematically, the author relates how air resistance was determined by wind-tunnel tests of various body models. Numerous illustrations are utilized to portray the models and the testing equipment, and the data obtained are tabulated and charted.
1933-01-01
Technical Paper
330001
E. J. W. RAGSDALE
Railroads are facing a crisis in operating costs, the urge toward reduction of unnecessary weight has become widespread and the crusade for noise abatement is no longer to be denied, according to the author. The pneumatic-tired railroad-coach not only answers these requirements, he says, but anticipates a demand for a new traveling comfort. The desire to rubberize railroad equipment is old but much fruitless research has resulted from directing it chiefly toward solid-rubber or cushion tires. Road and rail surfaces present entirely different problems so far as the tire is concerned. No uniformity of conditions obtains on highways but rails are even and smooth. A badly aligned joint such as would wreck a metal wheel makes no impression on a pneumatic tire. As simple as the tire problem may seem, its solution represents years of courageous and skillful research on the part of the Michelin company in France.
1933-01-01
Technical Paper
330006
Herbert Chase
“IN making these comments,” Mr. Chase says, “I am well aware that engineers are rarely given an opportunity to design a car incorporating even a large proportion of the improvements they would like to see included. “Unless some more or less ‘ideal’ types of construction are visualized, however, there may be no well-considered objective.” Visualizing these “more or less ideal types of construction,” Mr. Chase, in the following paper, throws a blanket indictment at the car designers, says what he thinks about current automobiles in no uncertain terms, and states specifically what he thinks ought to be done about it. Bodies, frames, springs, headlights, seats, engines-no unit of the modern car escapes Mr. Chase's stimulating criticism.
1933-01-01
Technical Paper
330010
Walter C. Keys
THE TERM “automatic transmission” is defined as meaning an automatically shifting sliding-gear or sliding-dog-clutch transmission with certain fixed gear-trains, or any type of mechanism which will produce automatically an infinite number of ratios between engine speeds and driving-wheel speeds. Various types of drive are considered, as well as typical automatic gearshifts, emphasis being given to the operation of the Tyler transmission clutch and to the Mono-Drive transmission. Other subjects are the reactions of operators to automatic gearshifting and the future of automatic transmission. The desirable features of an automatic transmission are stated as being reliability; quiet operation; reasonable cost, weight, simplicity and efficiency; and correct functioning, which means that it must do the right thing at the right time.
1933-01-01
Technical Paper
330018
B. B. Bachman
1932-01-01
Technical Paper
320039
Oscar C. Bridgeman, Hobart S. White
TEMPERATURE rise in the gasoline as it passes through the fuel system is the important factor in vapor lock that is within the control of the car designer. Gravity and vacuum-tank feed systems are considered briefly, including tests showing that weathering of the gasoline in the vacuum tank consists largely in removal of propane. Vapor lock in a pump system is most liable to occur on the suction side, because of the difference in pressure. Increasing the capacity of the pump for handling vapor offers little relief. Evidence is presented to show the gain made by locating the fuel line where it is protected from the heat. One example is cited to show the advantages of keeping a large flow of hot engine oil away from the pump. It is advantageous also to locate the pump where it will be cooled by the air entering the engine compartment of the car.
1932-01-01
Technical Paper
320014
Ralph S. Damon, George A. Page, Kendall Perkins
THIS thorough analysis of a subject that is of vital importance to airline operators reflects a great amount of experience and study. The collaborating authors endeavor to present a mathematical means for determining from cost records the type and size of airplane that will produce the largest net revenue under the operating conditions of a given route. Conditions that influence operation are listed; factors that make up the earnings are outlined, discussed in detail and their relationship to one another and to the conditions of operation shown. An example of the earning factors on an assumed airline is set up and the effect of several airplane characteristics upon earnings are shown by operating-cost illustrations. The estimates have been kept as close as possible to the average for prospective operation.
1932-01-01
Technical Paper
320023
AUSTIN M. WOLF
GENERAL DESIGN and detail mechanical developments that have been made in the last year and incorporated in automobile, truck and motorcoach models for 1932 are reviewed by the author, who also points out noticeable trends in a number of directions. He deals in order with the cars as a whole and with each major component, from the powerplant to the tires and body, as found in many leading makes. Decision of the industry not to announce the details of new models until the end of the year, at or immediately before the opening of the New York Automobile Show in January, interfered with the presentation at this time of a complete picture of all the improvements made in American motor-vehicles, but enough information is believed to be given to show the more important developments and the ways in which the automotive engineers have responded to the desire of the times for greater refinement and efficiency in automobiles.
1932-01-01
Technical Paper
320066
John G. Lee
LOW-COST maintenance is secured by attacking the problem before the design is started. The author tells how this important feature can be designed into the airplane. Maintenance requirements should be written into the contract specifications which should indicate the time within which each part should be inspected and serviced. A suggested set of such specifications is submitted. By this procedure maintenance time can be cut in half. The work of designing must not be rushed. To provide for quick maintenance, some broad changes from customary design are needed and will add to first cost but save money in the long run. Numerous recommendations are made as to design or type of important elements which will facilitate maintenance, avoid exasperation and add to passenger safety and comfort.
1931-01-01
Technical Paper
310040
Ford L. Prescott, Roy B. Poole
FOR the rapid calculation of bearing loads in aircraft engines the authors have developed an analytical method that is described for the first time in the paper. This was derived from the long tedious graphical method that was formerly used and its accuracy is asserted to be sufficient for all purposes of engine design. Results of an analysis of the bearing loads in the Curtiss V-1570 Conqueror engine which were obtained by the graphical method are first presented in considerable detail. The Wright R-1750 Cyclone is next analyzed, the method that was employed not being as precise as that used for the other engine. An application of the analytical method using empirical constants derived from a graphical analysis of various engines is also presented. Numerous illustrations and tables supplement the text.
1930-01-01
Technical Paper
300028
Oscar C. Bridgeman, Hobart S. White
The study of fuel flow in gravity-feed systems, which has hitherto been confined to flow through simple orifices, has been extended to include the measurement of flow through systems of various designs. The results of this study indicate that variations in the cross-sectional area of the feed lines from that at the tank outlet may have a marked effect on the vapor-locking tendency. Constrictions in the line and increases in cross-sectional area along the direction of flow are particularly liable to cause trouble from vapor lock. Experiments with commercial carbureters show that weathering of the gasoline in the carbureter float-bowl reduces the vapor-locking tendency of the fuel and, under certain conditions, may even cause an increase in the flow through the jet.
1930-01-01
Technical Paper
300016
A. W. FREHSE
MODERN brake-development is now reaching a stage in which the performance of a brake design can be predetermined accurately with almost the same certainty as that for powerplants. Accurate mathematical expressions and formulas now supplant the old cut-and-try method used on many types of brake. Armed with these mathematical tools, a designer can proceed with his designs without the usual misgivings and uncertainties that characterized former brake design. In practically every case, the original layout using the principles outlined has withstood the rigors of breakdown testing and field service, with very few modifications of a minor nature. Thermal and dynamic effects are disclosed, and their influence on the parts constituting the brake are discussed. These effects may spell success or failure in what looks to be a good design. The fallacies of the simple shoe-brake are discussed, and a method for overcoming them is offered.
1929-01-01
Technical Paper
290060
FRANK W. CALDWELL
WHILE much experimental work has been done on the controllable-pitch propeller, complexity of existing devices has prevented their being placed on the market. After reviewing briefly the difficulties encountered, due to propeller and engine characteristics, the author discusses the effect of camber ratio and of angle of attack on the speed at which burble occurs, following this with comments on the efficiency of propellers as static-thrust producers, the use of the method of momentum to compute thrust and the application of adjustable-pitch propellers to supercharged engines. The causes of the forces required to operate the control adjustments are given as (a) friction, (b) twisting moments produced by centrifugal force and (c) twisting moments produced by air pressure.
1929-01-01
Technical Paper
290021
RICHARD E. BISSELL, GORDON T. WILLIAMS
DESIGN and the material used in the construction of automotive poppet valves, particularly exhaus valves, are discussed in connection with the necessity of resistance of the valves to physical and chemical actions of wide variety. The problem of resisting these actions lends itself to mechanical and metallurgical solution. Each part of the valve-the head, the stem, and the end and tip of the stem-is discussed separately; and the design of the head is considered as it relates to the upper or combustion-chamber surface, the edge, the seat and the lower or manifold-radius portion. Provisions made for the grinding-in of the valves are shown and described.
1929-01-01
Technical Paper
290007
AUSTIN M. WOLF
1929-01-01
Technical Paper
290012
H. A. HUEBOTTER
ANALYTICAL methods of investigating engine torque are given in this paper, which is an amplification of the method previously presented by the same author, accompanied by a number of sample analyses. This method is said to be easier to apply to a complete analysis than is the graphical method, and to be adaptable to several types of investigation that cannot be made by the graphical method. In the discussion is given an outline of the mathematics required to follow the analysis. Electrical engineering students are said to receive instruction in all the mathematics required beyond that used in the graphical method.
1929-01-01
Technical Paper
290063
G. D. WELTY
A NUMBER of the more important commercial alloys having aluminum as their base are discussed by the author, who points out their main physical characteristics and outlines methods which can be used in their fabrication, indicating in a general way which alloys are best suited to various aircraft-engine requirements. Tables are given showing chemical compositions and physical properties, including a table of physical properties of various casting alloys at elevated temperatures. Special-purpose alloys are commented upon, and also a new aluminum alloy for pistons which is beginning to find commercial application and possesses properties particularly desirable in aircraft engines. Recent developments in magnesium alloys and their application to aircraft-engine design are specified, tables of physical properties are given, and comments are made on the characteristics of the material as compared with aluminum alloys.
1928-01-01
Technical Paper
280065
E. E. WILSON
Abstract THREE basic ways in which naval aviation can assist the battle fleet to attain victory are stated, and the aircraft are classified as fighting, observation, torpedo and bombing, and patrol planes. The primary and secondary uses of the types are set forth, and, since their tactical employment controls the features of their design, a brief sketch is given of the tactical considerations of fleet air-work. The development of naval aircraft to date and the trend of future development are then described. As naval fighting planes must be carried on the ships of the fleet and must have the utmost possible performance and service ceiling compatible with low landing-speed, their size and weight have been reduced by the use of air-cooled radial engines and the intelligent employment of light alloys and ingenious detailed construction. The latest development in this class is a single-seater designed around the Wasp 500-hp. engine and equipped with a supercharger.
1928-01-01
Technical Paper
280037
MAURICE PLATT
EUROPEAN trends in some of the major features of engine, chassis and body design and in several items of equipment are reviewed in this paper; which is based on the observation and analysis of the British engineer editor who is its author, and of the staff of The Motor, of London, during the last five years. Although American automotive engineers who follow European practice are acquainted with most of the designs here shown and described briefly, this paper is of interest and value as showing the present principal lines along which development is taking place abroad. Popular chassis types are divided into three classes: (a) the “baby” four-cylinder car of 7 to 9 hp., Royal Automobile Club rating; (b) the “family-type” four-cylinder car of 12 to 14-hp. rating; and (c) the light six-cylinder car of 15 to 20-hp. rating. Typical acceleration curves for well-known cars in each of these classes are given, as well as cylinder dimensions, volumetric capacity, car weight and price.
1928-01-01
Technical Paper
280048
H. A. HUEBOTTER
In this article the author presents analytical methods for determining the unbalanced inertia force and the tangential effort in a line engine. These methods are thought to be of interest for investigation of the effects of various engine design-features on its vibration characteristics. An equation for the resultant reciprocating force is set forth and methods of expressing the inertia and fluid-pressure torque are given. The determination of minimum and maximum resultants and the balance of inertia and fluid-pressure torques are other topics dealt with. The results of a series of analyses are incorporated in tabular form.
1928-01-01
Technical Paper
280034
R. E. PLIMPTON
TO solve fleet-operation problems successfully, a professional consciousness is needed among the supervisors and the engineers engaged in the operating field, awakened by analyzing and making known generally the methods and practices used by the operators of individual fleets of motor-vehicles, according to the author. In developing his subject he asks the following questions and comments upon them: Has the operator any influence on design? Is that influence good or not? Whatever the influence is, can it be improved and made more effective? If it can be made more effective, how can this be done? If it cannot be made more effective, what is the reason? Regardless of variations in duties and of conditions in organization, each large-scale operator is vitally concerned with matters of design and construction.
1927-01-01
Technical Paper
270052
H. D. CHURCH
The paper deals primarily with internal wheel-brakes for trucks and motorcoaches, but passenger-car brakes with similar characteristics are considered possible. A simple two-shoe internal-expanding type developed mainly by empirical methods is found to be the most practical solution in spite of relatively low circumferential contact. Self-energization is necessary to reduce driver effort with normal pedal-travel. The factors controlling self-energization are explained in detail, and the effect of difference in the coefficient of friction of brake-linings is noted. Distortion of brake-drum and brake-shoes must be limited by a drum of heavy section and by extremely rigid shoes. Rotation of cam with respect to self-energizing shoe should tend to deflect the toe of shoe away from brake-drum surface. A floating cam is necessary to balance unequal wear on the brake-shoes and assure adequate braking with normal pedal-pressure.
1927-01-01
Technical Paper
270034
M. V. DAVIDSON
MATHEMATICAL analyses of the force required to accelerate the reciprocating parts of six and of eight-cylinder engines and of the axial and perpendicular components of the force needed to accelerate the connecting-rod are presented by the author. He then shows mathematically that the division of the connecting-rod into reciprocating and rotating elements is correct theoretically. Having obtained exact expressions for the forces required to accelerate the reciprocating parts and the connecting-rod and having shown that the usual treatment given the connecting-rod is correct theoretically, mathematical study is made of the reciprocating balance of six and of eight-cylinder engines for comparative purposes and comparison is made numerically between six and eight-cylinder engines having equal total weight of reciprocating parts. A study of the angular acceleration of the connecting-rod is also presented in the article.
1927-01-01
Technical Paper
270016
F. M. HAWLEY
TOOTHED and friction-gearing are said by the author to be the two distinct classes of power transmission between two shafts, and the silent chain he describes is in the toothed-gearing class according to his statement, since it has a fixed speed-ratio and causes a bearing pressure that varies almost directly with the power transmitted. It is argued that, because of its elasticity and the peculiar method of contact with the teeth of the sprocket, the silent chain constitutes a medium that absorbs shocks and variations in angular velocity, and has a bearing action similar to that of a belt. The improved silent chain is made of stamped, arch-shaped link-plates assembled in alternate succession and joined by pins that act as bearings. The spacing of the pins forms the “pitch” of the chain. When assembled, the chain can be considered a flexible gear or rack.
1927-01-01
Technical Paper
270015
R. S. DRUMMOND
AFTER outlining the present status of the forms of drive for timing-gear trains, the author describes modifications of gear design made by the company he represents to overcome noise that involve lengthening gear-teeth for a given pitch. Various modifications in this regard were made and one having 16-pitch teeth with 12-pitch length had 10,000 miles of use in fourth speed without developing excessive wear. A further development resulting from experiments was the use of case-hardened timing-gears for motorcoach engines, such usage being thought to provide the most extreme conditions. Characteristics of so-called anti-stub gears are stated and predictions are made as to the future of timing-gear practice.
1927-01-01
Technical Paper
270071
C. M. KEYS
1927-01-01
Technical Paper
270069
CHARLES N. MONTEITH
MAJOR problems that have been encountered in the operation under contract of that portion of the Transcontinental Air Mail line between Chicago and San Francisco are outlined and discussed briefly. The more serious difficulties cited are: first, the operation of a single type of airplane from points at altitudes as great as 6400 ft. as well as at sea level, together with the fact that, in the case of this particular line, the heaviest loads are carried between the points of greatest altitude; second, the proper design of cowling and manifolding for the operation of the air-cooled radial engine at the extremes of temperature that are encountered throughout the year; and, third, the need for an engine that is geared down to the propeller or an engine delivering its normal power at a lower engine-speed.
1927-01-01
Technical Paper
270068
EDWARD P. WARNER
INFLUENCE that the research and development work done in aeronautics by the naval and military services has had in the advancement of design and construction of airplanes and aircraft engines suitable for commercial operations is pointed out and exemplified by citing a few instances of direct adaptability of military types of airplane to commercial uses. Nearly all of this work would have been done much later or not at all if the airplane had been purely a commercial vehicle, but the constructor for purely commercial purposes and the commercial operator have had the benefit of it. Major fundamentals, such as speed, safety, reliability and economy, are the same in both types of aviation; divergencies between the requirements for the two kinds of service begin to appear in materiel, personnel, or methods of operation only at a somewhat advanced stage of evolution.
Viewing 33151 to 33180 of 33251