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Viewing 169981 to 170010 of 170919
1924-01-01
Technical Paper
240006
ROGER BIRDSELL
Reporting on the progress of the fuel investigation now being conducted by the Bureau of Standards, and covering the last of the work that was done under the direct supervision of the late Stephen M. Lee, the author gives the results obtained from the acceleration tests that were made on the road and in the laboratory. Tests relative to starting conditions, as called for by the program, have yet to be made; they have been delayed by the wreckage of the laboratory set-up caused by the explosion of Sept. 20, 1923. Primarily, the tests described here were conducted (a) to determine whether the rates of acceleration obtainable at any given temperature are different for the fuels compared, and (b) whether, when carbureter settings are such as to give the maximum acceleration with each fuel, the fuel consumption under constant speed and load conditions will be greater with one fuel than with the other. Two specific conclusions are stated. W. S.
1924-01-01
Technical Paper
240005
H W ASIRE
Definite knowledge as to the behavior of gases and liquids in the manifold of an internal-combustion engine being lacking, an attempt is made to answer the questions: (a) How bad is the distribution, (b) how do the different types of manifold compare, (c) why is the liquid distribution in some manifolds poor and (d) how shall we proceed to correct the trouble? The solution of the problem is affected by the facts that, in extremely cold weather, nearly all fuel is delivered to the engine, at the time of starting, as a liquid; that all cars perform poorly under such conditions, some engines, when cold, “hitting” on only one or two cylinders; and that, because of inferior distribution, many multi-cylinder engines are outperformed by single-cylinder engines of similar design.
1924-01-01
Technical Paper
240008
C E Sargent
The efficiency of internal-combustion engines increases with the pressure of the charge at the time of ignition. Therefore, a compression at full load just below that of premature ignition is ordinarily maintained. But when such an engine is controlled by throttling, the efficiency drops as the compression is reduced, and as automobile engines use less than one-quarter of their available power the greater part of the time, the fuel consumption is necessarily high for the horsepower output. On account, also, of the rarefaction due to throttling, more power must be developed than is necessary to drive the car; automobile engines in which the fuel is introduced during the induction stroke, would be more efficient, therefore, if the maximum compression were constant during all ranges of load.
1924-01-01
Technical Paper
240007
C S KEGERREIS
Since previous papers by the author on this subject have dealt with the engine mixture-requirements at some length and these requirements are available to the public, only general information is included in the first part of this paper to illustrate the ideal carbureter-mixture requirements when using a fully developed acceleration device. In the second part, computed data illustrate the car carburetion-requirements of various cars for level-road operation. The car-test data were procured from various sources and combined with research results obtained in the Purdue University Engineering Experiment Station to delineate the factors desired. The results show the information regarding the advisability of using straight-line mixtures. The third part constitutes the main section of the paper, and especial attention is called to it.
1924-01-01
Technical Paper
240051
JOSEPH LANNEN
When the volume and the variety of the parts produced by a plant increase beyond the point at which the shop mechanic is capable of devising the methods and building the tools for accomplishing the desired results, it becomes necessary to make a division of labor, and a special department on tool division is needed to determine the proper sequence of operations and the suitable equipment to produce the required quantity with the required degree of accuracy. It is necessary that the men be informed regarding the daily and the ultimate numbers of parts to be produced and the tolerances that will be allowed. The foremost consideration of the production engineer should be economy of production. In this phase of tool engineering, the ultimate number of parts to be produced plays an important role and equipment should be selected that will give the maximum production. All known methods of production should be compared and the most economical one chosen.
1924-01-01
Technical Paper
240049
W L BEAN
Gasoline rail-cars for branches of trunk-line railroads and for short-line roads have been the subject of much discussion since 1920. Mechanical officers of interested railroads, the engineers of companies building highway motor-trucks and others specializing on this subject have now developed designs to meet the different service requirements. Several hundred cars of various types have been built and are in service. The railroad with which the author is connected has in operation or on order 24 cars. Consideration of several principal factors of design is necessary if a selection is to result in obtaining equipment suitable for the particular service requirements of the carrier and if the knowledge accruing from the engineering development and operating experience of the past several years is to be of value.
1924-01-01
Technical Paper
240050
A L DELEEUW
This paper is confined to a discussion of machine-shop operations, and is intended to indicate by a few examples certain important economies that might be introduced in the shops of the automotive industry. It deals chiefly with the economies that can be effected without much capital outlay, though others are also mentioned. Calling attention particularly to the fact that, in the past, improvements of methods and of equipment have been confined largely to the more important operations on the more important parts and that relatively little study has been made of the smaller pieces and the less important operations, emphasis is placed on the necessity for carefully determining which tools and which makes of tool will best serve the purposes for which they are intended and for carefully sharpening the tools and providing means of setting them accurately.
1924-01-01
Technical Paper
240022
ARTHUR T UPSON, LEYDEN N ERICKSEN
Shortage of the most desirable kinds of wood for automobile-body purposes has necessitated the substitution of second-choice woods having the essential required properties and the buying of stock for body parts in cut-up dimensions that conform in size with those now produced in the cutting-room. An investigation by the United States Forest Products Laboratory as to the species, kinds, grades, sizes and amounts used by the automotive industry shows that maple and elm comprise over one-half the total amount used and that ash and gum constitute one-half of the remainder. Although the quantity of ash used has not decreased, the increase in the production of medium and low-priced cars in the last few years bas caused a proportional increase in the demand for maple and elm.
1924-01-01
Technical Paper
240021
A J LYON, SAMUEL DANIELS
The importance of the development of a light alloy for use in parts that are subjected to elevated temperatures has already been emphasized in many papers, among which that by S. D. Heron on Air-Cooled Cylinder Design and Development4 should be particularly mentioned. It was with this purpose in view that the foundry of the Engineering Division of the Air Service at McCook Field undertook a brief survey of the alloying, the casting, the heat-treatment, the physical properties and the metallography of an aluminum-copper-nickel-magnesium alloy of the Magnalite type as sand-cast under ordinary foundry conditions. It was found that the alloying involved no particular difficulty. The casting, however, showed the necessity for proper pouring temperatures, gating and placing of the chills and the risers. Several photographs are shown illustrating satisfactory and unsatisfactory methods of molding pistons and air-cooled cylinder-heads.
1924-01-01
Technical Paper
240024
M L MCGREW
Because of tremendous demand for mass transportation over long distances in this Country, railroad equipment has become less and less suited for small transportation needs; but a large amount of small-unit transportation exists which can earn a profit for the railroads if they have the equipment best suited to handle it. Gasoline-propelled rail-cars have demonstrated their ability to meet the needs of this small-unit traffic. Types of such rail-cars now operating range from 25-passenger or 10 tons of freight capacity to 60-passenger or 30 tons of freight capacity; in certain services, their capacity can be increased by using trailers and by running them in trains operated by one driver at the front end, who has them under multiple-unit control, at speeds up to 50 m.p.h. and for from 20 to 50 cents per car-mile.
1924-01-01
Technical Paper
240023
RICHARD W MEADE
Double-deck horse-drawn buses did not meet with much favor in the United States, but from the earliest days have been popular with persons of all classes in England, probably due in part to the British nation's love of outdoors and in part to the governmental policy of prohibiting the carrying of passengers in excess of the seating-capacity. Packed vehicles continued to be characteristic of transportation in this Country until public service regulation in the early days of the present century required that a reasonable number of seats should be provided. When the number of passengers was limited to the number of seats, at the time of the introduction of motorbuses on Fifth Avenue in New York City, the failure of the experiment was predicted, whereas subsequent service has proved it to be the cornerstone of success. London double-deck tramcars with 78 seats require about 3 sq. ft. of street space per passenger, while the latest type with 50 seats require about 4 sq. ft.
1924-01-01
Technical Paper
240026
J F WINCHESTER
Solicitation of sales and the delivery of the product to the customer constitute the most important operative features of the motor-truck fleet supervised by the author. Endeavor is made to install the vehicles in the various fields along standardized lines. The volume and the extent of the business and the topographical conditions of each locality determine the size and the mechanical equipment of the vehicle that is employed, and it is installed only after a study of all the conditions pertaining to its operation. Adequate training of vehicle operators, not only along mechanical lines but also as direct sales representatives of the company, is made a feature; and so is accident prevention. These interests are promoted in various standard ways and are furthered by the publication of “house organs.” After a vehicle is installed the slogan adopted is: Keep It Moving With a Pay Load.
1924-01-01
Technical Paper
240025
E J BRENNAN
A brief summary of the history of motor rail-car equipment on the railroad represented by the author is given in his paper. Three gasoline-driven rail-cars were put into operation in 1910. The engine used for each car was a six-cylinder, 10 x 12-in., slow-speed, four-cycle reversible-type having overhead valves, an open crankcase and a 200-hp. rating, but experience has proved that the four-cycle reversible-type engine equipped with an air-operated starting-apparatus makes rather a complicated unit that is the cause of many difficulties. Details are given concerning these first three cars, their performance and the changes made in their equipment. In 1922, a two-car train consisting of a motorcoach and a trailer was installed. The coach is 28 ft. long, has a 12-ft. baggage-space, carries 30 passengers and weighs 28,000 lb.; the trailer is 32 ft. long, weighs 17,000 lb. and seats 36 passengers.
1924-01-01
Technical Paper
240027
R E PLIMPTON
Operating costs and their relation to the age of the vehicle have been a subject of controversy for some time. One faction maintains that after a certain indefinite period it is economy to salvage or junk the equipment and replace the vehicles with later uptodate designs. The opposing faction believes that the costs depending on maintenance and operating efficiency can be kept fairly constant. Comparing a motor truck with a locomotive they cite the opinion of railroad officials that when proper running repairs are made locomotives can be maintained continuously in the same service and retain their original earning capacity for many years. When new locomotives are built it is usually for the purpose of replacing types that have become obsolete and the old ones are then relegated to some other branch of the service.
1924-01-01
Technical Paper
240028
George J. Mead
ABSTRACT
1924-01-01
Technical Paper
240014
F F CHANDLER
Lack of scientific research is specified by the author as being the cause of failure to develop steering-systems generaly to meet the present need for better and easier steering-ability. He comments upon the meager data available regarding steering-system faults and factors that influence design and emphasizes the necessity for determining the live stresses in steering-systems while the vehicle is traveling over roads of all kinds, so that designs can be made with greater confidence and greater safety attained. Defining comfort as being inclusive of easy steering, a comfortable sitting position, convenient location of the controls that must be handled frequently and peace of mind relative to steering accuracy and dependability, he analyzes the causes of hard steering, saying that the steering-system includes every part from the steering wheel through the steering-gear and linkage to the front wheels and that the steering-gear itself is simply the reduction mechanism. Assisted by H.
1924-01-01
Technical Paper
240013
N S DIAMANT
In the first part of the paper, a general quantitative comparison of air, water and oil-cooled cylinders is given as it relates to the subject of heat-transfer and temperature drop. Unfortunately, the discussion does not include experimental data, but the assumptions are stated clearly and a large range of values is covered in Table 2 so that any desired values can be chosen. A thorough and comprehensive discussion of the steam or the radio-condenser type of cooling is given under the headings of Steam Cooling Systems, Characteristics of Steam Cooling Systems, Cooling Capacity of Radiators Used To Condense Steam and Present State of Development. In the second part, an attempt is made to give a thorough but brief discussion of the performance or of the operating characteristics of radiators from the point of view of the car, truck or tractor designer. The cooling of aircraft engines is not considered.
1924-01-01
Technical Paper
240016
GEORGE L. SMITH
Describing first the two methods of brake application in use in the United States, the theory of balanced brake-forces is then propounded by the author, who compares the methods and comments upon them. Illustrations are presented and used to analyze the brake forces, and practical applications of an equalizing mechanism used in road tests of an automobile are stated and considered in some detail. Tests on wet pavements were made and skidding was studied, the skid-checking effects being noted and explained. Additional tests were made on hills, and the results of these are included, together with a presentation of the effects of speed and pressure. Wear on the tires and on the brake-lining, the effect on steering ability, the advantages of an automatic signal that brake-adjustment is needed, and the measurement of individual brake-force are the other subjects discussed.
1924-01-01
Technical Paper
240018
L A DANSE
The Cadillac Company has used S.A.E. 3250 steel for at least 8 years. This is medium nickel-chromium steel. Many other kinds have also been tried. Experience has shown that transmission gears made of carburized steel are not within 30 per cent as accurate as those made of oil-treated steel. This may be because of the fact that more attention has been paid to oil-hardened than to carburized steel gears. Efforts to control the distortion of carburized gears were unsuccessful. The hardening was done in salt pots, lead pots and open furnaces, heated by gas, oil and electricity. The same thing applies to spur gears. Oil-treated steel for rear axles has not been tried. When transmission gears were made from drop-forged blanks made by the conventional pegged-out process from flat stock they became oval. Upset gear forgings are used as fast as the forging suppliers can become equipped for the work.
1924-01-01
Technical Paper
240015
HENRI PERROT
Following a review of four-wheel-brake development, the author quotes from a scientific note relative to four-wheel-braking action on a car that is rounding a curve, published by the French Academy of Science, and the conclusion therefrom that front-wheel brakes have a direct retarding effect on the motion of translation and, in addition, a direct retarding effect upon the instantaneous motion of rotation of the car about its own center of gravity. Further, from another article, he quotes authority for the theoretical advantage of four-wheel brakes on heavy down-grades. Subsequently to an amplified statement that satisfactory operation of a four-wheel-brake system, from the driver's viewpoint and with reference to pedal-travel and pedal-pressure, constitutes the real problem, comparisons are made between internal-expanding and external-contracting types and the servo-brake is discussed with special reference to the Perrot system.
1924-01-01
Technical Paper
240017
O H SCHAFER
Graphical demonstration is given of the desirability of grinding gears that are made of carburized material. The warping of carburized gears is shown to be due to the shrinking of the carburized metal. The teeth cut on the regular commercial type of hobbing machine vary in form; those cut on a simplified hobbing machine are more accurate. Tooth forms made from oil-treated steel are much better than those made from carburized and hardened steel. The conclusion is that carburized gears must be ground, but when oil-treated and accurately cut on a simplified hobbing machine grinding may be necessary only when the teeth have become mutilated.
1924-01-01
Technical Paper
240020
Edwin M Baker
The quality of plated steel may be tested by exposing the article to the action of a salt spray and noting the appearance at intervals. A numerical method of rating the appearance is presented, and the rust resistance of steel plated with nickel and copper is shown to be dependent on the thickness of the plating. The effect on the salt-spray resistance of some common variables in nickel-plating, such as boric acid, ferrous sulphate, current density and defective steel, is disclosed and charted. The need of close technical control of the plating process is indicated, and some of the advantages of controlled electroplating at high current-densities are set forth.
1924-01-01
Technical Paper
240019
GORDON LEFEBVRE
Recent improvements in the mechanical equipment and the processes employed in the various car-assembling plants of a large motor-car-building company are described. As a result of the changes these departments have been transformed from the most unsightly parts of the factory into the cleanest, most comfortable and least dangerous. The processes to which special attention is devoted are those for the enameling of fenders and sheet-metal parts and such small parts as various stampings, forgings and malleables and cover the application of two coats of an asphaltic-base enamel and a subsequent baking at about 450 deg. fahr.; in body enameling they cover the application of three coats of similar material and baking at from 290 to 350 deg. fahr. The course of the various parts is followed from the time of their receipt to that of their delivery to the assembling department to which they belong.
1924-01-01
Technical Paper
240037
E H LOCKWOOD, L B KIMBALL
A portable instrument of the seismograph type has been designed for measuring the riding-quality of vehicles. Headings are made by a continuously revolving counter that automatically sums up the vertical displacements of a partly suspended weight. As the counter readings are a measure of the riding-quality, a large reading indicates poor riding and, conversely, a small reading indicates good riding. An arbitrary scale graduated into revolutions of the counter per mile of travel translates the readings into riding-quality; a reading of 10 indicates “very smooth,” 20, “good,” etc. The instruments have been calibrated in a special testing-machine in which the readings can be observed under an harmonic motion of fixed period and amplitude. Comparison of the riding-qualities of balloon tires and of cord tires, made on three different automobiles run over a variety of roads, shows results that are very favorable to balloon tires.
1924-01-01
Technical Paper
240038
S P HESS
Riding-comfort is defined as the transportation of an automobile passenger in so easy a manner that the trip will be a pleasure and not a hardship. Since spring-suspension constitutes the basis of riding comfort in passenger-cars, the paper deals with some of the important factors that determine correct chassis spring-suspension. An analysis made by the National Automobile Chamber of Commerce of replies received to a questionnaire it circulated among 20,000 car-owners is presented in proof of the genuine interest the motoring public has in the riding-quality of a car and the variable factors that have an influence on spring-suspension are stated to be the type of spring used, its physical dimensions, the amounts of sprung and unsprung weight, frame construction, wheelbase dimension and the kind of material used. Horizontal, vertical and sidewise motions of a car are analyzed, and a periodicity chart is shown for passenger cars of from 112 to 116-in. wheelbase.
1924-01-01
Technical Paper
240039
JOHN J MCELROY
An air-spring and a steel-spring combination has a characteristic load-curve that allows maximum flexibility in the general working-range of the axle yet has an increasing resistance to dissipate large shock-loads. By varying the compression volume in the air-spring, the load curve of the combination can be made more flexible or stiffer as occasion demands. Tests show that the steel-spring vibration alone had a duration of 5½ sec. with a period of 87.2 vibrations per min.; the combination, a 3-sec. duration with 60.0 vibrations per min. Field tests of front-axle movement were made, the test apparatus for these and other tests being illustrated and explained. The maximum axle-movement either above or below the normal line is increased when using air-springs, and the subsequent rebound shows more action on the underside of the normal line, the general tendency of the air-springs being to float the chassis on a slightly higher plane at the time of rebound.
1924-01-01
Technical Paper
240040
J E HALE
Balloon tires have caused the points at which the greatest trouble formerly occurred to be reversed; the greatest wear hitherto has occurred on the rear tires; now it occurs on the front. The carcasses of old tires were heavy and thick and carried a large part of the load; balloon tires are flexible and will support very little load. The air-pressure carries the load and gives greater cushioning effect. Four-ply tires have proved to be the most satisfactory and have none of the disadvantages of high-pressure tires. Balloon tires steer harder than high-pressure tires because of lower air-pressure, which necessitates a greater area of contact. Steering resistance is caused by the load on the tire and the increased area of contact. Many designers, in making the steering gear free to overcome steering resistance, make wheel-twitching possible. Shimmying may be classified as low-speed and high-speed, the latter occurring at speeds between 35 and 40 m.p.h. and being very violent.
1924-01-01
Technical Paper
240041
R B DAY
Shimmying was noticeable before four-wheel brakes began to be used, but since that time the trouble has been greatly increased. Two kinds are distinguishable; (a) low-speed shimmying, a violent wabble of the front wheels about the king-pins without a bouncing of the front axle, and (b) high-speed shimmying, a severe bouncing of the front axle during which one hub is up while the other is down. This occurs at somewhat higher tire-pressures and at high car-speed. Believing that both forms are not correctible by changing the design of the tire and are only slightly affected by changes in the steering-gear, efforts were directed toward prevention rather than correction.
1924-01-01
Technical Paper
240043
TOM W GREENE
In this investigation to determine strength and physical properties 12 motor-truck rear-wheels were tested, comprising two each of the following types: Class-B trucks, standard wood; Class-B truck, cast-steel; I-beam type; steel disc; aluminum; and rubber-cushion, each having a 34-in. diameter and a 12-in. tread. The wood, the I-beam and the cushion wheels each had 14 spokes; the aluminum and the steel-disc wheels had a solid web between the hub and the rim. All the wheels were tested without tires or brake-bands, were bushed to fit a 4-in. axle and the area of contact between the hub and the bushing was the same as that in service. Illustrations show the construction of the wheels. Requirements considered essential in a wheel were listed, and the tests were conducted to obtain data concerning them. One wheel of each type was subjected to a radial-compression test.
1924-01-01
Technical Paper
240042
WILLARD F ROCKWELL
Tendencies of the industry toward lower costs have been reflected in axle design. Large-volume business has made it worthwhile to introduce changes in the design of passenger-car and light-truck axles to increase production economy and improve design. For heavy trucks, the trend has been to keep costs down by making no changes that would involve added expense for tools, jigs, dies and fixtures. Front-wheel brakes for passenger cars have resulted in changing front-axle I-beam sections and front-spring design to take care of the increased stresses such brakes introduce. In the design of rear axles for passenger cars, no fundamental change has occurred, although the change from the full-floating and three-quarter floating types to the semi-floating axle and a change in mounting the bevel pinion are two features that seem to be coming to the fore.

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