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1926-01-01
Technical Paper
260017
O T KREUSSER
Layout, facilities and activities relating to making road-tests of motor vehicles at the 1125-acre proving grounds of the General Motors Corporation near Detroit, this tract being designed to provide a place where road conditions are suitable for obtaining data that can be interpreted accurately, compared with similar data and used constructively, are outlined and illustrated. Adequate facilities are provided and ideal road-conditions have been established so that motor-vehicle tests involving endurance, speed, acceleration, hill climbing, riding-quality and other comparative tests can be made. Conditions are such that tests can be repeated from day to day, thus compensating for the variations of the weather and other factors. Complete and conclusive tests can be carried out readily and promptly, and the results are free from guesses and personal opinions. The speed track is 20 ft. wide and nearly 4 miles long. Traffic is in one direction, clockwise.
1926-01-01
Technical Paper
260022
WALTER D'ARCY RYAN
Subsequent to reviewing the circumstances responsible for the present complicated situation existing with respect to satisfactory automobile-headlighting, the author says that headlights glare if they are adjusted for range and that, when adjusted for non-glare, they have no range; hence, careful tests were made on a number of the best types of approved headlight and lens in use. The units were set-up in pairs, in operating position as to height and interval and were tested at a range of 100 ft. with a 1-m. (39.37-in.) hemisphere having an aperture 21 in. square, corresponding to 1 deg. at 100 ft. All the lamps were held at proper current-value throughout the tests, and it was demonstrated by the tests that the reflectors of the parabolic type and others of similar characteristics that have proved to be unsatisfactory during many years past must be abandoned.
1926-01-01
Technical Paper
260023
L C PORTER, G F PRIDEAUX
Since the layman and not the engineer buys and drives most of the automobiles produced and because the literature on automobile headlighting presents to[ILLEGIBLE] technical a picture of what happens when the light source of an automobile head-lamp is out of focus, the authors planned and executed an extensive study of the subject in an endeavor to clarify the technicalities by presenting them in the forms of photographs and simple charts, the chief object being to obtain data that emphasize the necessity of accurate control of the size and location of the light source with respect to the focal point of parabolic headlight-reflectors. A great difference in the resultant beam of light is produced by a very small displacement of the light source, either through poorly constructed lamps or due to lack of proper adjustment, and the tests made evaluate how small these displacements and how great these differences are.
1926-01-01
Technical Paper
260025
H F Parker
Although the generally accepted spheres of usefulness of the airship and the airplane are usually based on their comparative ranges of operation and their speeds, the suitability of either of these types for a given purpose is primarily dependent on two classes of factors, those fundamentally dissimilar and those roughly similar. Conclusions as to relative usefulness should be based on a consideration of the dissimilar characteristics, which include aerodynamic efficiency, size and comfort. Aerodynamic efficiency governs range and, since it determines fuel consumption, influences the cost of operation. The size required depends on the paying loads that are available for carrying. Comfort concerns passenger-carrying only. As the propeller efficiency, rate of fuel consumption and ratio of weight of fuel carried to gross lift are similar in both types of aircraft, the range must depend on the L/D factor, that is, the ratio of gross lift to thrust.
1926-01-01
Technical Paper
260032
T. S. SLIGH
Elementary theories regarding the evaporation characteristics of pure substances and mixed liquids are discussed briefly and the difficulties likely to be encountered in attempts to calculate the volatilities of motor fuels from data relating to pure substances or in the extrapolation of volatility data corresponding to the atmospheric boiling-range of the fuel to the range of temperatures encountered in utilization of the fuel are pointed out. A brief review of previous methods of arriving at fuel volatility is also presented. Volatility, as applied to motor fuels, is defined as being measured by the percentage of a given quantity of the fuel which can be evaporated under equilibrium conditions into a specified volume. The weight of air under known pressures is taken as a convenient measure of the volume. The new method described is an equilibrium distillation of the fuel in the presence of a known weight of air.
1926-01-01
Technical Paper
260034
W. G. WALL
Lubricating-oil, despite the abuse it receives, is expected to perform its function properly. Road dust, gasoline and water are allowed to mix with it, and it is subjected to a high temperature and mixed with carbon, so that the original oil soon becomes hardly recognizable. Some remedies that have been proposed provide for the removal of either the dirt or the dilution, but both should be kept out. Water not only dilutes the oil, but forms sulphurous acid, rusting the parts and, in winter, probably freezing at the oil-pump. When mixed with oil, it forms an emulsion and when this emulsion is mixed with road dust or carbon particles, sludge is gradually formed. Sludge, when agitated and sucked through the oil-pump, tends to clog the oil-holes and to wear the bearings. Oil, when exposed to a high temperature on the cylinder-walls, becomes oxidized and black in color. Sulphur in the fuel probably forms sulphur dioxide and, by mixing with water in the crankcase, becomes sulphurous acid.
1926-01-01
Technical Paper
260037
FERDINAND JEHLE
In undertaking any experimental work the first step is to plan carefully each successive step. Literature bearing on the subject should be examined to learn what work others have done on the problem and avoid needless duplication of effort. If the testing of only a simple accessory is involved, the results the device is intended to accomplish should be studied and an effort made to discover the designer's reason for believing that it will accomplish them. All conditions under which such a device must operate should be listed and the information needed from which to draw conclusions as to whether the device will meet them successfully should be determined. Before starting the actual work of testing, it is good policy to plan the necessary charts for presentation of the report. This preliminary work means that the investigator will start well prepared but not with his mind made up as to what the results will be.
1926-01-01
Technical Paper
260039
FRED S. DUESENBERG
Development of the two-cycle high-speed supercharged engine used in the Duesenberg racing cars that competed in the 1926 500-mile Indianapolis race is described. Excessive trouble in starting the engine, which requires considerably higher supercharger pressure than does the four-cycle engine, inclined the designer and builder to abandon the idea of using this type of engine in the race. The supercharger gear-ratio was not laid out for the extreme speeds and, as the engine speed is directly proportional to the supercharger pressure, the pressure was too low to give the desired speed. The speed and efficiency of the engine were increased by increasing the width of the cylinder intake-ports, but the author believes a supercharger pressure of 15 lb. per sq. in. is necessary for good operation. Best results were obtained when the rotary valve opened the intake valve after the exhaust ports had been opened about 3/16 in.
1926-01-01
Technical Paper
260042
L. R. BUCKENDALE
Progress in the development of automotive worm-gearing is interestingly outlined. Previously tO 1912, American experience had been limited almost exclusively to the industrial form, generally of the single-thread type. Introduction of the motor truck required a worm for the final-drive but one having entirely different characteristics from that of the industrial gear. Experience in designing these was lacking, however, as was also the special machinery to produce them. In 1913, machinery was imported from England and since that time development has been rapid. First efforts were devoted to simplifying the design of the axle as a whole, studying the problem of getting lubricant to the bearings, heat-treating the parts, and improving the materials of construction.
1926-01-01
Technical Paper
260043
G. H. ACKER
Subsequent to a brief review of the development of the worm-gear drive for motor-trucks and the gear-ratios considered most desirable, the author discusses comparatively the worm-gear and the spiral-bevel gear with regard to their application for specific service, as well as with regard to their cost and length of life. It is brought out that the worm-gear is, after all, very similar in action to any sliding, or journal, bearing. A certain amount of involute rolling-action takes place in the action of the gearing, the magnitude of which increases with the gear-ratio; but the primary action is one of sliding of the worm-threads across the gear-teeth. Simple as this fact is, the prejudice fostered by many people against worm-gears can be traced to lack of appreciation of it. Due to the nature of the surfaces in contact, the best obtainable bearing takes the form of a narrow strip running across the gear-tooth, and the bearing pressures obtained are high.
1926-01-01
Technical Paper
260009
D M PIERSON
Because of the great increase in the winter use of automobiles resulting from general highway improvement and a doubling of the percentage of closed cars produced in the last 5 years, the problem of satisfactory operation of automobiles at low temperatures has assumed far greater importance than prior to 1920. It has therefore become necessary to make a more intensive investigation of the difficulties encountered in winter driving and of means for their avoidance. Study of low-temperature operation on the road is unsatisfactory because of the many variables in the conditions and the sudden and extreme changes that occur; consequently a refrigerated laboratory in which cars and engines can be tested under constant conditions that simulate as nearly as possible those met in road driving in winter is highly desirable.
1926-01-01
Technical Paper
260052
Charles M. Manly, C. B. Veal
After quoting statistics that show the alarming increase in thefts of automobiles and analyzing numerous conditions under which automobiles are stolen, the authors discuss locks as theft retardants, saying that the providing and the improvement of locks has always been man's method of seeking security from thieves and comes in naturally for first consideration as the normal course to pursue in working toward adequate theft prevention. The present identification systems in use are mentioned, together with their features of advantage and disadvantage, and numerous practices that owners and drivers can adopt which tend to minimize theft are cited. The early forms of locking device are outlined and statistics are included which show the percentage of cars actually locked when they are equipped with a locking device.
1925-01-01
Technical Paper
250066
G J Mead
Infallible performance and economical operation are the bases of successful commercial flying. Airplanes, having passed through the experimental and demonstration periods, must now prove their usefulness. Heretofore, because of military requirements, designers have fostered the use of power rather than refinement of design to obtain performance, but commercial operation demands efficiency, and in each of the four essentials, namely, dependability, size, total powerplant weight and cost, opportunity for decided improvement still exists. The requirements and limiting factors of each of these essentials are discussed in turn and the conclusion is drawn that a relation exists between the amount of thrust delivered to the air and the weight put into an airplane for its propulsion. To obtain the best over-all performance, if these terms are considered as a fraction, the numerator should have the maximum and the denominator the minimum value.
1925-01-01
Technical Paper
250063
LOUIS RUTHENBURG
Industrial development has out-run foreman development, in the author's opinion. He believes that management should be alive to the changed status of the foreman and that it should train him definitely to accept a broader responsibility. Clarification of the situation should start with the assumption that the departmental foreman is to be held definitely responsible for every activity that affects his department; but, obviously, he cannot be given direct authority over certain functionalized services that very directly affect the operation of his department, and he must, therefore, develop that higher type of executive ability which can obtain results without the club of direct authority. In short, instead of conceiving the departmental foreman as the master craftsman of his department, he should be looked upon as the business manager of his department.
1925-01-01
Technical Paper
250062
LILLIAM M GILBRETH
Successful production demands the greatest volume of output with the least amount of effort. It is of prime importance in industry, and its slogan is the elimination of waste, considering always the worker, surroundings, equipment and tools and the methods or motions used. Therefore, it is necessary to give attention to training employes in production work. The paper evaluates training in terms of production and formulates the elements that have proved effective, the aims of such training being to develop a better worker in the particular job, to produce a better member of industry and to create a better member of society. The worker always must be judged with relation to his work, and no more important psychological test exists than that of aptitude for the job.
1925-01-01
Technical Paper
250059
W G Careins
The selection of machine-tools is largely a matter of judgment, based on the consideration of many variable factors. No fixed rules can be laid down, but the uses to which the machines are put are divided roughly into three classes which govern to a large extent the types of machine that should be purchased, whether they should be machines of a wide range of usefulness, standardized machines equipped with special tooling or special-purpose machines of special design capable of very large and continuous production. To determine into which of these classes the requirement for new machines falls, an analysis should be made of the following factors: (a) quantity of production required and its duration, (b) method of machining and tolerances and finish required, (c) possibility of a change in design of the product, (d) cost of production, (e) when delivery of machine is required, and (f) money available for the purchase.
1925-01-01
Technical Paper
250057
PERRY L TENNEY
Periodically recurring problems of gear noise and wear which seem to arise from no specific cause frequently affect the manufacturing side of the automotive industry and especially the gear-manufacturers. While much has been written and discussed about the mathematics and geometry of gears, which should overcome all of these problems, the trouble unfortunately still persists. The paper outlines the experience of the organization with which the author is connected in solving a rather difficult problem that offered an opportunity for a more thorough analysis than did its predecessors. Laboratory and dynamometer analyses of the product showed that it compared favorably with the output, of other factories.
1925-01-01
Technical Paper
250056
J G MOOHL
Stating first the several important factors affecting jig-and-fixture design, the author emphasizes the necessity for cooperation between the engineering and the tool-engineering department and says that, in the plant specified, the tool engineer determines the position of locating points for machining operations on the engine block. Details of the first machining operation are given and the methods of loading and clamping the work are outlined. By adhering to accepted principles of design, and by utilizing all other means of cost-reduction, equipment of the plant with adequate jigs and fixtures is accomplished at minimum expense. Use of duplicate clamping parts on as many jigs as possible saves time and reduces the stock of replacement parts needed. Strength and rigidity of fixtures are essential. Heavy base-sections are necessary, bushing plates should have a section deep enough to prevent warping and ample chip-clearance should be provided between the fixture and the work.
1925-01-01
Technical Paper
250055
W D'A Ryan
Although agreeing in general with the sentiments expressed by Mr. Crane and Mr. Hunt, exception is taken to the statement that the solution of the headlighting problem is to be found in diffused lighting, because it has not sufficient range, is too glaring and is too dangerous in a fog. The trouble is said to lie not in the specifications but in the devices that they are supposed to cover. Suggestions are offered regarding modifications that might advantageously be made in the present specifications, and a detailed summation is given of the requirements considered essential to a first-class headlight. The statement is added that a headlight embodying all the points enumerated, while at the same time using a 21-cp. bulb, has already been perfected.
1925-01-01
Technical Paper
250053
H M CRANE
After referring to the recommendations made to the National Conference on Street and Highway Safety by the Committee on Motor Vehicles and the Committee's further explanation of the recommendations, the author amplifies more fully the difficulties that have arisen in the operation of the system of headlight regulations sponsored by the Illuminating Engineering Society and this Society and suggests a line of fundamental research with a view to drafting more desirable regulations. Inasmuch as road conditions have changed greatly since the regulations at present in force were first proposed, he believes that a new study of the subject might result in marked improvement. Definite control of a concentrated headlight beam, deflected below a horizontal line, as originally proposed by the Society, failed to produce the desired result, and the next step was the formulation of the regulations listed in the S.A.E. HANDBOOK.
1925-01-01
Technical Paper
250051
C O GUERNSEY
Various efforts have been made to apply the internal-combustion engine to self-propelled rail-cars. The greatest development along this line prior to the war was in connection with the McKeen and General Electric cars that were built from 1906 to 1914. The builders of those cars were greatly handicapped by the lack of available experience in connection with the design of gasoline engines, particularly of the larger type. Since the war a gradual development of rail-cars has taken place, starting with small converted motor trucks and gradually increasing in size and adaptability to the service, until now gasoline-electric cars of 250 hp. and about 75 ft. in length are available, while mechanically driven cars are available up to 190 continuous horsepower.
1925-01-01
Technical Paper
250069
J J FEELY
Following a description of airplane structure, the author discusses structural requirements and outlines the main features of properly coordinating the engineering and the manufacturing activities. He says that each of the three subdivisions of airplane design has its own series of calculations, these being related to predictions of performance before the machine is built, to stability determinations and to the design of a self-contained structure of sufficient strength to withstand any stresses developed in flight or in landing. He states also that no inspection is worth the name or the money spent on it that does not include constructive work and a knowledge at all times that the intentions of the designers are being carried out in detail so that the safety of the craft is assured. Materials used in aircraft should be light and easily workable and should possess the desired physical and chemical properties; they must have the specified cross-section and be free from defects.
1925-01-01
Technical Paper
250067
W L GILMORE
A racing airplane seems to possess a special quality that sets it distinctly apart from the conventional type of airplane; but, unless a person has at least dabbled in its design, he cannot realize the enormous amount of time, effort and ingenuity that has been expended by the designers who have made these super-speed airplanes possible. Therefore, an outline is given of the procedure adopted in designing and producing a specific model of racing airplane, as well as an outline of the yearly progress made in development. The first procedure is to allocate the work to the various members of the engineering organization. Finally, a type of design is chosen after a series of engineering conferences, and the design section studies the detail design of the component parts. A wing section that is adapted to the design already chosen is developed, and an accurate weight estimate is made of each unit part of the complete airplane.
1925-01-01
Technical Paper
250068
THOMAS H FROST, WALTER E RICHARDS
Principal stresses in one type of eye-bolt have been determined in the laboratory of photoelasticity at the Massachusetts Institute of Technology by the photoelastic method. In the test, an eye-bolt, designed in accordance with a method suggested for circular eyes in a course in machine design by the Institute, was made of celluloid 0.25 in. thick, 1 in. wide on either side of the eye, with a 1.405-in. diameter of eye, and a 1.333-in. width of shank. Steel loading-plates were pinned to the broadened end of the shank and a load of 100 lb. was suspended from the bolt, which gave a mean stress of 300 lb. per sq. in. in the shank. Plain polarized light was passed through the celluloid model and the isoclinic lines, or lines of equal inclination of principal stress, were observed and recorded. Two families of lines of principal stress, designated as P and Q stresses, were determined graphically from these isoclinic lines.
1925-01-01
Technical Paper
250033
D P BARNARD
General laws governing the rate of flow of oil through complete journal bearings are developed in the paper. These laws are based on the assumption that axial flow obeys Poiseuille's Law and is, therefore, a function of the bearing load. Dimensional reasoning indicates that the volumetric efficiency of a bearing considered as a pump is given by an equation of a form in which efficiency equals a function of the viscosity times the rubbing speed divided by the bearing load, the length divided by the clearance and the length divided by the diameter. Experimental evidence is presented which substantiates this point of view. The general relation of rubbing speed to heat generation and oil-flow is discussed for the purpose of indicating a possible solution of certain high-speed-bearing problems. A plain bearing is, in effect, a pump in which the flow of a viscous lubricant through a passage of varying area develops a pressure sufficient to sustain the imposed load.
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