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Viewing 12751 to 307 of 307
1932-01-01
Technical Paper
320048
W. S. James, F. E. Ullery
HYDRAULIC shock-absorber characteristics are analyzed by the authors with the aid of indicator cards made on a machine designed and built for the purpose. The machine is shown in a diagrammatic drawing and is stated to have been used with much satisfaction for more than two years. Curves of the action of dry and lubricated springs with and without shock-absorbers attached are shown and the statement is made that the resistance of the shock-absorber does not increase fast enough, as the speed of link movement increases, to damp the spring suitably at both large and small deflections. Indicator cards from shock-absorbers of several types reveal the effects of incorrect design of the valves and of dirt in the oil passages. The effect of change in viscosity of the working fluid as a result of temperature changes is discussed and attempts to obtain a fluid that is not thus affected are declared to be fruitless.
1932-01-01
Technical Paper
320045
Louis Ruthenburg
1932-01-01
Technical Paper
320070
George A. Green
COMPARATIVE tests were made, both on the block and in the same motorcoach chassis, of a 525-cu.-in. gasoline and a 495-cu.-in. Diesel engine. The block tests are reported fully in charts, including curves for torque and power against piston displacement and engine weight. Corrected curves are given on the basis of equal piston displacement and for the Diesel engine throttled enough so that it would not smoke. Road tests included fuel consumption, acceleration, hill climbing and top speed, which are also recorded in charts. Other sections of the paper deal with costs of manufacture and maintenance and present and prospective conditions as to supply and cost of Diesel fuel. Stress is laid on the facts that automotive Diesel engines require a much higher grade of fuel than do the larger and slower Diesel units and that more gasoline than fuel oil can be obtained from a given amount of crude.
1932-01-01
Technical Paper
320069
C. F. Taylor
HEREIN are presented the results of an investigation of the bending moments in the master rod of a radial aircraft engine by a graphical method, and a simple formula derived therefrom for approximating this moment in similar engines. The bending stress in the master rod comes from turning moments about the crankpin axis caused by the action of the articulated rods due to gas-pressure and inertia forces and also by the inertia forces in the master rod itself. Charts are presented that show the magnitude and fluctuation of these turning moments. Accurate computation of these moments involves much tedious work. A method of approximating them with sufficient accuracy for engineering purposes is given for the case of a nine-cylinder radial aircraft engine. The method is applicable also to non-radial engines and to radial engines having other than nine cylinders, but in these cases investigation of the turning moments due to the gas loads in certain cylinders seems advisable.
1932-01-01
Technical Paper
320064
Alex Taub
AS engineering standards have risen, the need for production ingenuity has become greater than ever before. The engineer looks to the shop for major assistance in realizing his ideals of improved products. He expects the shop voluntarily to reduce the variations from dimensional specifications and to improve its facility to meet changes in design. Refinement in design is useless unless the shop can accurately hold the dimensions. Powerplant characteristics are largely controlled by the accuracy of centers and roundness and straightness of bores in cylinders and bearings. Crankshaft balance, quiet valve tappets and uniformity of weight and fit of reciprocating parts are all dependent upon accuracy of machine operations. To be able to make design changes in the product without great expense is vitally important. Tools must be designed with facility for change. Fixed-center boring machines are to blame for considerable engine trouble and may make design changes prohibitively expensive.
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.
1932-01-01
Technical Paper
320010
Stephen J. Zand
THIS paper supplements one on the same subject by the same author, published in October, 1931, and describes a new and improved three-component vibrograph with which separate vibrograms of the three components can be obtained simultaneously and with considerable magnification. A short mathematical analysis is given to show the fundamental difference between vibrographs and accelerometers. Effects of vibration on different instruments are discussed and the approximate maximum permissible amplitude of vibration at cruising-speed frequency for various instruments is presented in a table. Consideration is given to correct design of instrument-boards and their suspension in an airplane, and the theory of forced vibration with damping is reviewed to show that, if not rightly chosen, shock-absorbing materials can do as much harm as good.
1932-01-01
Technical Paper
320012
Ford L. Prescott
OPTICAL, balanced-pressure, electrical and sampling-valve indicators are discussed with particular reference to their shortcomings. Sampling-valve indicators possess the advantage of simplicity, as compared with the balanced-pressure type, and make a permanent record on ordinary indicator paper. The sampling or averaging type and the electric or instantaneous type each has fields of usefulness not covered by the other. The electric indicator is claimed to be the most satisfactory device for transient and qualitative work such as combustion study, but the sampling type is said to be better suited for engine development, valve-timing studies, supercharging and similar work.
1932-01-01
Technical Paper
320001
James W. Cottrell
TRAILER registration figures for the entire United States are given to show the rapid increase in the use of trailers in the last seven years, and, for comparison, State registrations of all motor-vehicles in 1931 are given. To account for the relatively more rapid increase in trailers than in trucks, factors favoring the use of trailers are mentioned and illustrative examples of operation are briefly described. The factor of first importance is legislation, which in general is stated to have promoted the use of trailers to distribute the weight of heavy loads over more axles and wheels; but in some States the laws and regulations have a serious adverse effect. Next to legislation, savings in hauling costs through the use of trailers account for the increase in their numbers, and comparative figures of the cost of hauling per 100 lb. per 100 miles by truck, by truck and trailer and by rail are given to show the economy.
1932-01-01
Technical Paper
320027
Joseph S. Newell
CONSTANT improvement in airplanes involving increased speeds and increased maneuverability permits of their performing evolutions that were not contemplated when present strength requirements were established. Additional data and experience, however, make possible the breaking down of some of the problems involved into components that can be treated rationally and others that must still be handled empirically. A method for determining load factors in the high-angle-of-attack condition by the use of two rational variables and one empirical coefficient is described and applied to some 19 airplanes, the results being compared with the factors established by current practice.
1932-01-01
Technical Paper
320028
C. B. Stiffler
PROVIDING ample stock to guard against the possibility of the interruption of production for lack of material was the chief aim of inventory control in 1920. Recognition of the importance of turnover is one of several factors that have led to a study of minimum stocks. Inventories received first consideration in the now well-established financial-control policies of the General Motors Corp. Formerly, placing orders for materials far in advance of needs had been thought necessary to assure the supply, but restricting orders to suppliers to three months in advance has been satisfactory for 10 years. Each car division of the Corporation now submits a definite monthly forecast, based on 10-day reports from dealers of stocks and actual and estimated sales, which estimates the number of cars to be sold by the dealers, delivered to the dealers and manufactured during the current and three forward months.
1932-01-01
Technical Paper
320022
Austin M. Wolf's
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
320024
Roy W. Brown
METHODS are outlined for measuring the characteristics of tires that affect riding-qualities, and typical curves showing rate of deflection and contact area versus tire size are presented. Coordination of service performance with simple laboratory tests is illustrated. Means of securing the inter-effect of tires and springs are outlined and curves of typical axle-body frequency versus tire size are shown. Use of the solenoid accelerometer in conjunction with equipment for interpretation of physical effect of accelerations is suggested for service tests. Secondary riding-quality factors such as tire traction, horsepower and rim diameter are discussed and numerous others mentioned. The influence of tread design and other factors of tire design is indicated.
1932-01-01
Technical Paper
320017
H. M. Williams, J. W. Carl
SALES potential of refrigerator trucks seems to be several hundred new units annually, according to the authors. Motor-truck transportation of meat, milk, ice cream, fruits and farm produce demands refrigeration, as does delivery-truck transportation of butter, cheese, yeast and dough. Large trucks are needed for the former class and smaller ones for the latter, but the refrigeration problems are fundamentally the same. Desirable body-construction is outlined and the different refrigerating systems are analyzed with regard to quantity of refrigeration needed, type of insulation and insulating material available. Mechanical systems are discussed under electric, power take-off and separate gasoline-engine drives for the compressor. The most desirable location for a refrigerating unit on a truck also is considered.
1932-01-01
Technical Paper
320020
Graham Edgar
INCREASING realization by automotive engineers and by oil refiners that the nature of the fuel available largely determines engine-performance possibilities has resulted in valuable cooperative research, important progress and the preparation of a firm groundwork for future progress. The author outlines the more important characteristics that automotive-engine fuel should possess and indicates some of the relations existing between possible engine efficiency and fuel characteristics. Heat of combustion of a fuel, volatility, tendency to detonate and freedom from impurities are discussed. Actual data from two commercial cars for which optional cylinder-heads were available are presented.
1932-01-01
Magazine
1932-01-01
Technical Paper
320056
Maxwell N. Halsey
DISPARITY between the factors of automobile and highway design that are far advanced and the factors that lag far behind constitutes the cause of many of our transportation difficulties, according to the author. The paper therefore aims to show the demand for safety and its economic advantage to the automotive industry and to indicate some of the principles necessary for its accomplishment. After stating that the automobile manufacturers should take a far-sighted view of the situation, take positive steps toward safety and cash in on the demand that is growing and that cannot be stopped by denying its existence, the author considers and comments upon some of the characteristics of automobiles that undoubtedly are partly responsible for accident potentialities. Visibility from the driver's seat is considered in detail, together with devices that assist visibility. The other driver's viewpoint also is considered.
1932-01-01
Technical Paper
320011
Richard C. Gazley
RECENT developments disclose the existence of a well-defined tendency toward greater accuracy and thoroughness in airplane stress-analysis methods, which serve only as a link between applied loads and allowable loads. This trend has just begun. “Although we may justly look with pride on the aeronautical achievements thus far accomplished,” the author says, “our knowledge and ability are far from being complete or entirely satisfactory.” Hence, he analyzes several recurrent stress-analysis problems and indicates methods leading to their solution, because these seem to be outstanding in their ability to cause trouble for airplane designers. Better understanding is needed of the peculiarities of aircraft structure; such as lack of rigidity, the nature of inertia loads, the effects of flutter and of engine vibration, and the dangers of stress concentration.
1931-12-01
Magazine
1931-11-01
Magazine
1931-01-01
Technical Paper
310001
A. J. Blackwood, N. H. Rickles
1931-01-01
Technical Paper
310004
E. S. Marks, C. T. Doman
FEATURES of the design of the various cylinders built by the Franklin organization in its development program leading up to the present design are discussed in this paper. The relation of waste heat to cooling-fin areas and cooling-blast velocities is shown and discussed for cylinders up to 3½-in. bore. Characteristics of the cooling system, including fan, fan housing and air housings, are discussed at length, and the authors contend that no more power, if as much, will be absorbed in the cooling system as in that of the indirect air-cooled engine. Results of tests showing the ability of the engine to cool under the severest conditions of load and temperature are given. Since the quietness of any engine is dependent upon constant valve-clearances, the authors describe in detail the method followed in the Franklin design to maintain at less than 0.003 in. any variation in clearance. A careful analysis is made for each part in the valve-gear mechanism that is affected by expansion.
1931-01-01
Technical Paper
310009
H.C. Mougey
THE PROBLEM of oil consumption must be solved before the problem of winter starting and winter lubrication can be solved, asserts the author, since winter starting and winter lubrication require light oils, and light oils give poor results as regards oil consumption. Eight factors affecting oil consumption are listed in the order of their importance. Some of the reasons why they affect oil consumption are given and suggestions as to methods of overcoming the difficulties are made. The author concludes that oils of low viscosity, which are required for winter starting, can be made to give satisfactory oil consumption at all engine speeds by necessary changes which probably will involve other mechanical features besides those usually considered in connection with design of the lubrication system. They may include improved bearings, oil-coolers, air-cleaners, oil-filters, better control of cylinder and piston cooling, and other factors.
1931-01-01
Technical Paper
310010
W. H. Bahlke, O. FitzSimons, D. P. Barnard, J. O. Eisinger
THE Conradson carbon-residue test is the generally accepted method for predicting the relative quantities of carbon an oil will deposit in an engine. This belief arises from the fact that, although publication of results of earlier researches in this field have shown that volatility of the oil is a controlling factor, it has been assumed that in all cases volatility is measured by the carbon-residue test. The results of tests conducted by the authors, covering a period of about two years, show that no such general relationship exists when the carbon-forming characteristics of a wide variety of oils are considered. This conclusion is drawn from 50-hr. tests of a large number of commercial lubricating oils in an engine operating under fairly heavy load and at moderate speed. The authors found that the volatility of the oil is the primary factor in engine carbon-deposition, and a laboratory method was developed for indicating the total volatility of a motor oil.
1931-01-01
Technical Paper
310035
Richard V. Rhode
THE PAPER supplements the paper on Weight Saving by Structural Efficiency2, prepared by Charles Ward Hall. Mr. Hall's paper was confined to a discussion of the design; Mr. Rhode's paper treats the loading conditions, because their sound establishment is the foundation of a safe and efficient structure. The basic character of the loading conditions is sufficient cause to justify extensive study of their underlying principles, since, in addition, structural failures are occurring which can be traced definitely to inadequate strength requirements and the study of the loading conditions becomes a problem of immediate practical importance, the author states. Mr. Rhode's analysis is confined to the loading conditions on the wings of airplanes in the non-acrobatic category with particular reference to the total loads acting.
1931-01-01
Technical Paper
310036
Stephen J. Zand
AIRPLANE vibration produces many undesirable conditions during flight, such as fatigue of structural members, a bad effect on the nervous systems of the occupants and the like. Excessive vibration leads to premature deterioration or to erroneous indications of instruments. Vibrations can be analyzed from a mathematical viewpoint with gratifying results, but such analysis is sometimes difficult and often is applicable only to selected conditions. A serious mathematical analysis was carried out in the investigation of resonance conditions between engine and engine mount. Then the problem was approached from a rather empirical viewpoint to give vibration relations, not, as heretofore, to bodily sensation, but to such terms as amplitude, frequency, the relation between the two, form and the like.
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.
1931-01-01
Technical Paper
310045
L. A. Blackburn, J. W. Brussel, A. R. Fors
IN THIS PAPER, obsolescence is considered as concerning the economic value of a machine regardless of its physical condition or age. Improved machinery may make a tool obsolete while it is relatively new. Distinctions are drawn between obsolescence, depreciation and amortization, and a list of controlling and contributing factors in obsolescence is given. Objection is made to the lumping of obsolescence and depreciation in a single charge, which apparently is not great enough to cover obsolescence with the present accelerated rate of machine-tool progress. Three examples are given of formulas or methods of determining the economic advisability of purchasing new equipment, and their use is illustrated by being applied to a set of assumed conditions. Yield, risk and liquidity are said to control investments in new equipment, the same as any other investments.
1931-01-01
Technical Paper
310014
A. D. Gardner
STATING the automotive cooling-fan problem as being constituted of the delivery of more air, decrease of fan horsepower, reduction of fan noise so that it is comparable with or less than other powerplant noises and the installation of the fan in a restricted space, the author describes the testing apparatus and method used in analyzing the subject. Fan speeds and the most effective number of blades are then considered, followed by analyses of fan diameter and pitch and curvature of fan blades. The manner in which air is discharged from the fan and the adaptation of a fan to an automobile are also discussed. Following statements concerning the desirable number of fan blades and blade spacing, noise characteristics of fans are analyzed in detail as a preface to the author's consideration of means of reducing fan noise, and a summary listing the conclusions reached as a result of the study is appended.
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