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1925-01-01
Technical Paper
250026
F A MOSS, H H ALLEN
Although many variables enter into the personal equation of the driver of an automobile, this paper concerns principally his reaction-time. The tests described had for their objects the determining of (a) the average time that elapses between the hearing of a signal, such, for example, as the shot of a pistol, and the applying of the brake; (b) the relation between the reaction-time and the variability of the individual; and (c) the effect on reaction-time of such factors as the speed of driving, training, age, sex, race, and general intelligence. The reaction-time was determined by two pistols mounted on the under-side of the running-board of an automobile and pointed toward the ground, the first being fired by the experimenter when the car had reached the desired speed, the second, by the person under test in making the initial motion of operating the brake-pedal.
1925-01-01
Technical Paper
250027
L M WOOLSON
Advances in airplane performance during the last few years may be ascribed mainly to advances in aerodynamics and to improvements in powerplants. The latter have resulted in producing more power for the same weight of engine and smaller over-all dimensions for engines of the same power-rating. The accompanying paper describes two engines of 500 and 800 hp. respectively that have been recently developed by the Packard Motor Car Co. for aircraft service. When these engines are compared with previous types they are found to be more compact and to produce more power per pound of weight. When each is operated at its rated speed, the Model 1500 engine develops 100 hp. more than the Liberty while weighing 140 lb. less, and the Model 2500 engine develops 250 hp. more than its predecessor, the Model 2025, with a decrease in weight of 75 lb.
1925-01-01
Technical Paper
250024
J H HUNT, G F EMBSHOFF
Electrical instrumentation for research work has been developed to a high degree because of the great speed of action and the convenience of application of the electric current. The current serves to transmit instantly to a recording instrument the impulses imparted to it by a detecting device. There is available a great wealth of indicating, integrating and recording devices that can be used readily for automotive research by the aid of auxiliary devices, some of which can be purchased and some of which can be easily made in any ordinary model shop or toolroom. In the study of automotive mechanism the research engineers have drawn upon the investigation work of men in other lines of industry and have found it necessary to go back of these men to the scientific investigators who are attacking the elements of various problems in the physical and chemical laboratories.
1925-01-01
Technical Paper
250025
J E MILLS
Successful operation of a general service-station depends upon the application of several business fundamentals. The service division of a car sales organization can be made to produce a fair profit by following proper methods, but the importance of the service division as a possible asset or liability has only recently begun to be recognized by the more progressive sales companies; surprisingly few service-station operators or managers have attempted to study the condition and to correct faults and increase the efficiency of their shops, while fewer still have any definite control-records for their guidance. Too many organizations try to conduct their service divisions with little or no attempt to follow the business principles that are observed by the foremost corporations in many lines of industry, with the inevitable result that the monthly balance sheets of the service-stations vary from a heavy loss to a fortunate profit.
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
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
250070
J E WHITBECK
The personnel and the ground facilities that have produced such excellent results in the Air Mail Service are discussed apart from the flying equipment and its operation in the air. An airway is on the ground and the performance and safety of the pilots are dependent upon the ground facilities provided and the efficiency of the ground personnel. Pilots perform a highly important part in the operation of airlines and no matter how good the flying equipment may be, the desired results cannot be obtained without thoroughly trained and capable pilots. When selecting new pilots, the Air Mail Service looks for men who handle an airplane in a businesslike way and who are able, without taking unnecessary risks, to fly the ship without letting the ship fly them.
1925-01-01
Technical Paper
250064
E F COLLINS
Will sheet steel that is to be used in the manufacture of automobile parts form the parts for which it is intended without breaking, buckling or pulling coarse at the sharp corners is a question, the answer to which is sought through a series of tests applied to samples of the material by the Packard Motor Car Co. Three sheets are selected from different parts of every 1000 sheets received. After sections have been removed from the ends of these sample sheets, four test pieces are taken from each sheet at specified locations and these last samples are subjected to Erichsen, Rockwell and tensile-strength tests, each of which is discussed.
1925-01-01
Technical Paper
250065
MARC STERN
Subsequent to an historical review of die-casting, briefly stated, the author covers the subject of present die-casting practices comprehensively and conveys a large amount of specific information. Because many different methods of producing castings exist outside the sand-casting realm, he says that some confusion prevails as to the exact definition of the term “die-casting.” Such castings may be produced in metallic or in non-metallic long-life molds, or in combination with destructible cores. They may be filled by gravity and known as “permanent-mold castings”; or by centrifugal force and known as “centrifugal castings”; or by filling the mold by gravity and, after the outer skin has become chilled, pouring out the excess metal. The last named are known as “slush castings.” On the other hand, a die-casting may be defined as a casting formed in a metallic mold or die, from metal subjected to mechanical or gaseous pressure while in the molten state.
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
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
250060
A R KELSO
Machine-repair analysis and a criticism of present-day equipment, with analytical tables based on data collected from a 5 months' study, are followed by conclusions relative to the reliability of present-day equipment. Eight types of common machine-tools are considered and the maintenance advantage of one over the other is deduced from the consolidated tables based on monthly reports. A comparison of each class of machine-tools with the others is made, as well as a summary of the weaknesses of each class from the frequency of repairs of the elementary parts. The attention of the builders is drawn to the conditions that the shop encounters with their equipment. A maintenance budget-system is described that has been installed in one plant to give the men a comparative idea of particular equipment that is running in excess of the budget time. It also serves in lieu of an inspection of the conditions of the equipment and is an indication of the time when overhauling is advisable.
1925-01-01
Technical Paper
250061
R F THALNER
Evolving gradually since the time when opinion prevailed that accidents are unpreventable, modern safety methods have come into being and successfully organized effort concentrated on their application in industry has accomplished an amazingly effective system of accident prevention. In the automotive industry, effort focused on preventive measures looking toward the elimination or reduction of casualties and fatalities has resulted in greatly increased conservation of life and property; but, as new conditions and new demands continually appear, it is evident that new methods, new means and new modifications must be continually in process and that putting these forces into production requires concentrated scientific study, forethought and executive ability.
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
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
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
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
250058
C J ROSS
With the passing of the apprenticeship system and the introduction of the present method of employing unskilled labor on a piecework basis for assembling, careful inspection has become a necessity. Under these conditions, the only way in which the product can be held to the required standards is to make the component parts fit accurately. If the inspection is adequate, parts can be held to closer limits and cheaper labor can be used in the assembling process. Believing that no reason can exist for failure to maintain standards of accuracy if the ratio of the number of men engaged in production to one inspector does not exceed 15 to 1, the officials of the Buick Company have worked out a system, similar in many respects to a budget, in which a certain ratio of production hours to inspection hours is allowed in each plant, the number depending upon the nature of the work and varying from about 10 to 1 in the engine plant to about 34 to 1 in the gray-iron foundry.
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
250017
W R STRICKLAND
Although wheel wabble, even with high-pressure tires, is of ancient origin and the general methods of controlling it have been well understood, its importance among present-day problems is due to the fact that the recognized specific for its treatment, namely, increasing the air-pressure in the tires, has been denied. Shimmying, as generally applied, includes wabble, or the sidewise vibration of the front wheels about the knuckle-pin, and tramping, or the bouncing of the wheels vertically, alternately on the two sides. In addition to discussing the advantages and disadvantages of the low-pressure tire, the author has enumerated the results of tests, some of which have been obtained from original research work by himself, others from the literature on the subject, with a view to determining whether shimmying is caused by defects in design, and what are the effects when certain modifications are introduced.
1925-01-01
Technical Paper
250016
R B DAY
Shimmying, although known for many years, did not become a serious problem until the arrival of the balloon tire and the four-wheel brake. Apparently, shimmying is of two kinds: the low-speed variety, which is merely a persistent front-wheel wabble without an abnormal bouncing of the axle, and the high-speed species, which is chiefly a persistent bouncing of the axle accompanied by wabbling of the wheels. The two most obvious effects are wheel wabble and axle bounce. As low air-pressure seemed to be the cause, the attention of the tire makers was first devoted to stiffening the body of the tire in various ways, but the results obtained were not satisfactory; and the conclusion was reached that the solution lay in making the car control the tire rather than attempting to control the car through the design of the tire. These considerations led to a search for mechanical means of control.
1925-01-01
Technical Paper
250019
B J LEMON
The balloon tire has run the gauntlet of skepticism and credulity and has received scientific and popular approval from engineers and car-owners. The reasons for its acceptance are satisfactory appearance, practicability and transportation comfort. Tire and rim sizes, masquerading for years under wrong dimensional markings, have caused immeasurable inconvenience. This condition resulted from poor standards or entire lack of standards supervision. A committee with backbone is needed to fix and to maintain standards. Rapid balloon-tire tread-wear depends on tread profile, pressure and movement. Increased inflation-pressure and a scientifically designed tread will reduce the rapidity of this wear. Tread-contact areas and pressures are pictured to explain the advantages of a properly designed tread, and to demonstrate that the casing carries an appreciable part of the tire load.
1925-01-01
Technical Paper
250018
J W White
Inasmuch as the use of low-pressure tires has become established, the conditions of car design affected by them are reviewed, particular reference being had to the members of the chassis included under the term unsprung weight, namely, the axles, the wheels and the tires. Referring to the principles that underlie basic design, the author first investigates the effect on the steering of such changes and compromises from the perfect structure as failure of the king-pin to coincide with the vertical load-plane, the inclination of the king-pin toward the wheel, or the wheel toward the king-pin, or both, and the giving of a toe-in to the front wheels. Further modifications have served to reduce the car shock, to add to the strength of all the parts by increasing the dimensions, to improve the spring-suspension, and to reduce the car weight per passenger.
1925-01-01
Technical Paper
250021
GEORGE W KERR
Body construction, of a character such that the wooden framework is secured by suitably shaped steel joining-plates and bolts that separate the wooden members ⅛ in. at the joints, is illustrated and described. The outer surface of the body is completely covered with flexible textile fabric or leather-cloth. It is claimed that the effect is to impart to the finished body an easy deformability and to permit it to accommodate itself to distortions of the chassis frame, to which it is rigidly attached. A portion of the English patent specification is quoted, and details of the actual construction practised at the inventor's factory in Paris, Prance, are stated. Due to the absence of steel and to the extreme slenderness of the wooden parts, these bodies are very light. The required wood-working operations are few and simple. Only the minimum machine equipment is needed to fabricate the framework, and no great skill is demanded in its erection.
1925-01-01
Technical Paper
250020
E A De Waters
In the summer of 1922 the Buick Company began experimenting with balloon tires. The first tires tested, being four-ply and 32 x 6.20 in. in size, produced a galloping action that was sufficient to prejudice the company's engineers against them, and the tests were discontinued. In addition to the galloping effect, other difficulties encountered included those usually present in steering, the development of wheel shimmying to a serious degree, the lack of proper clearance for external brakes because of the small 20-in. wheels, the excessively rapid wear of the tire tread, and the greater susceptibility to puncture. Leaks because of the pinching of the inner tubes also occurred. When, later, a set of 5.25-in. tires was tried on a smaller car, the galloping was noticeably less; but punctures were more numerous than was the case with high-pressure tires.
1925-01-01
Technical Paper
250023
JOHN A C WARNER
Due to tremendous production schedules and rapid advancement, the automotive industry is characterized by its effort to learn the answers to engineering research-problems with utmost dispatch, but the procedure is not without attendant risks. Costly errors have resulted from experimental work improperly planned and executed, from conclusions too quickly drawn and from unjustified interpretation of observed indications. Cut-and-try procedure is resorted to in many instances after hastily applied research methods have failed and, often, the apparently longer course involving systematic research would, in fact, have been fruitful of more prompt and more satisfactory results at a lower net cost. As originally presented, the paper was accompanied by a demonstration of instruments and apparatus especially adapted to automotive-research problems.
1925-01-01
Technical Paper
250022
EDWARD G BUDD, J LEDWINKA
All-steel automobile bodies are lighter, stronger, roomier, and cheaper than composite bodies having wood framing and metal panels. They are free from squeaks, afford better vision of the road and scenery, take a superior finish with less preliminary work, and permit marked economies in quantity production. Steel has 40 times the strength to resist breakage that wood has and, in bending, may be stressed 7 times as much as wood, hence the cross-sectional area of steel members may be only a small fraction of that of wood members having equal strength. This makes for lightness of construction and reduction of the size of frame members, thereby affording more space in the interior of the body for the passengers and reducing the amount of obstruction to vision.
1925-01-01
Technical Paper
250009
A H HOFFMAN
Rapid wearing out of the engines of farm tractors, trucks and automobiles led the University of California to undertake a study of the dust problem and the efficiency of air-cleaners in removing field and road dust from the air before it passes into the engine. Work was begun in 1922 and several reports have been made on the methods devised and the progress made during the last 2 years. Results to June, 1924, were given in the paper published in August, 1924. The present paper gives results of the studies to the end of 1924 and includes data from tests of 12 new makes or models of air-cleaner not previously tested or not fully tested. Of outstanding importance is the discovery that the quantity of dust inspired by any cleaner or carbureter is greatly reduced if the intake is placed high and faces away from the direction of motion of the vehicle.
1925-01-01
Technical Paper
250008
A H HOFFMAN
Utilizing an opportunity presented by a mountain-road construction-project in California, eight Class-B 3½-ton trucks were assigned to the work and a test of air-cleaners was conducted during its progress. Six trucks were each equipped with an air-cleaner; two were not. The trucks had dump-bodies and were specially prepared for the test, details of this preparation being specified. Due to varied air-cleaner design, it was not feasible to locate the cleaners identically on all the trucks, and differences in mounting may have influenced the resulting air-cleaner efficiency, but mountings were made as nearly identical as possible. Tables of average wear of piston-rings, engine cylinders and crankpins, for 1000 hr. of use, are presented, and details of how the measurements were made are stated, together with a discussion of the “growth” of pistons and of the peculiarities of wear.
1925-01-01
Technical Paper
250011
ETHELBERT FAVARY
Benefits gained by distributing truck weights and loads among six wheels rather than four, include less liability to cause road destruction, greater carrying capacity and more economical operation. The author classifies the causes of road destruction under headings of excessive loads on tires, impacts between road and tires, traction effects of wheels, and braking effects and says that the remedy is to reduce load or to correct improper weight-distribution. Impacts probably contribute most destructive effects.