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Viewing 110581 to 110610 of 112266
1936-01-01
Technical Paper
360124
D. J. Vail
DEVELOPMENT of cast camshafts at the Campbell, Wyant & Cannon Foundry Co., starting in 1924, proceeded slowly until a material was developed that met all requirements from metallurgical, engineering, and manufacturing standpoints. “Proferall,” the name given this material, means processed-ferrous-alloyed iron made by the duplexed-electric-furnace process. Camshafts of this material have a Brinell hardness of 262-293, as cast. A series of tests, equivalent to runs of 46,560 miles, showed that both chemical analysis and hardness affect camshaft-gear wear. Comparative wear tests on bearings showed more than three times as much wear on steel camshafts as cast ones. Other tests showed the cast shafts expanded less than those of steel. After describing foundry processes the paper concludes by summing up the advantages of cast camshafts, such as the smaller cost of patterns as compared with forging dies and the elimination of heat-treating, copper plating, carburizing, and hardening.
1936-01-01
Technical Paper
360125
George L. Neely
THIS paper describes briefly why extreme-pressure lubricants are necessary and what machines most commonly have been used to evaluate them. Examples of differences in test results caused by differences in operating conditions, by the type of machine used, and by the method of installation of the machine are presented. The new S.A.E. Extreme-Pressure-Lubricants Tester is described, and the probable advantages of the machine are discussed. Other requirements of commercial extreme-pressure lubricants are listed. In conclusion, the statement is made that the new machine is believed to constitute an approach to the gear problem that is more sound fundamentally than that of any of the other machines that have been used. In the older machines one or more of the test surfaces was always stationary while, in the S.A.E. Tester, both surfaces are in motion and a combination of sliding and rolling friction approaching that of gearing may be achieved.
1936-01-01
Technical Paper
360122
F. C. Mock
THERE are two main requirements as to proper preparation of the fuel charge for rapid combustion in our present engines: (1) The fuel must be vaporized, or in a similarly small order of subdivision, before ignition. (2) The fuel and air must be intimately mixed. Light fuels, such as our present aviation gasoline, may be vaporized in the carburetor and supercharger to quite a satisfactory degree, providing that the intake air is heated when flying at low temperatures. With this system, as we know, the air and fuel mixing is quite thorough. Heavier fuels, if released in the carburetor, may not vaporize in the intake-air flow, but instead may puddle and trickle on the side walls. Under such conditions, not only does the fuel fail to reach the cylinders in metered charges but also, if and when it should do so and if it vaporizes in the cylinder rather than getting on the cylinder wall, there is usually inadequate means for mixing the vapor with the air charge.
1936-01-01
Technical Paper
360123
H. Wood
THIS paper gives a brief resumé of the development of the Rolls-Royce Kestrel engine and then analyzes the requirements of the high-performance engine of the future, developing at least 1500 b.hp. and operating on fuels of high knock ratings. The problems investigated include those of engine form, fuels, detonation, waste-heat disposal, cooling drag, cooling medium, and the mechanical and operational features. Conclusions deduced from the arguments are: (a) Compression ratios, charge density, and rotational speeds will need to increase and, therefore, cylinder bores and strokes will decrease; it may be necessary to adopt the sleeve-valve type. (b) The arrangement of the engine will tend to multithrow crankshafts with more than two pistons per crankpin.
1936-01-01
Technical Paper
360120
T. B. Rendel
ADOPTION of cetane-number scale and primary and secondary reference fuels, calibration of secondary reference fuels agreed upon, test procedure, and results of tests comprise the important points stressed in the second report of the Volunteer Group for Compression-Ignition Fuel Research. Cetane number, which is the percentage of cetane in alpha methylnaphthalene that matches the ignition quality of the samples under test, has been adopted by the Group as the standard method for reporting results. For actual use in routine testing, suitable secondary reference fuels are available: a high-cetane fuel from the Shell Petroleum Corp., and a commercial grade of methylnaphthalene for the low-cetane fuel. A calibration curve of the secondary reference fuels in terms of the primary standards is included.
1936-01-01
Technical Paper
360121
Raymond W. Young
DURING the past decade the general trend of aircraft-engine design has continued toward increased piston displacement, higher crankshaft speed, higher brake mean effective pressure, and improved materials. These changes have had a marked influence on increasing the overall performance of the airplane by improving take-off, bettering climb, permitting higher cruising speeds at greater altitude, increasing periods between overhaul, and improving the reliability of the powerplant. Although of secondary importance until quite recently, today fuel economy has become a major objective in both military and commercial operation. Fuel consumption is a function, generally speaking, of engine design, of the properties of the fuel itself, and of the procedure for introducing and regulating the fuel-air mixture in the operation of the powerplant.
1936-01-01
Technical Paper
360118
P. H. Schweitzer, T. B. Hetzel
Abstract IN the testing method described in this paper the moment of ignition is determined by a mechanism consisting of a diaphragm in the cylinder head, a phonograph “pick-up,” a short stiff wire transmitting the motion of the diaphragm to the pick-up, a thyratron relay, and a neon lamp protractor. When ignition occurs in the cylinder the flexing velocity of the diaphragm is sufficiently high so that the voltage generated in the coil of the pick-up trips the thyratron tube and permits a high-tension condenser discharge to be sent through the neon lamp which by its flashes then indicates the time of ignition. Because of the absence of friction and arcing the action of the pick-up is more regular than that of a bouncing pin. A similar pick-up is used for indicating injection timing.
1936-01-01
Technical Paper
360133
E. M. Barber, B. A. Kulason
IT is the purpose of this paper to present a chart by means of which the vapor-locking characteristics of a gasoline (represented by a curve showing the quantity of vapor formed as a function of the temperature) can be estimated with moderate accuracy for gasolines in the current commercial distillation ranges from the conventional Reid vapor pressure and A.S.T.M. distillation tests on the gasoline. Interpretation and consolidation of car data are facilitated by means of the chart and, in this respect, vapor-lock test data are given for eight 1934, eleven 1935, and several 1936 model cars. The use of the chart and car data is illustrated by a group of sample problems which are specially designed to show the degree of assurance that may be placed on the use of either Reid vapor pressure or A.S.T.M. 10 per cent point alone as a criterion of vapor lock. The problem of evaporation losses from the fuel system, which can be roughly treated by means of the chart, is also discussed briefly.
1936-01-01
Technical Paper
360119
J. R. MacGregor
DATA are presented showing the results of extensive tests of Diesel fuels of widely different ignition characteristics in laboratory and service engines. The tests in laboratory engines are particularly significant in demonstrating the influence of controlled differences in operating conditions upon the relative ease of ignition of fuels. The tests in service engines show that each engine has distinct minimum requirements for fuel-ignition quality; that the minimum required is different under different operating conditions; and that no essential difference in the performance of fuels can be noted as long as the minimum ignition quality is exceeded. For all practical purposes, therefore, no correlation appears possible between the laboratory rating of Diesel fuel ignition characteristics and service behavior.
1936-01-01
Technical Paper
360132
P. A. Anderson
THIS paper deals with air-cooled aircraft-engine installations and covers such units as cowling, engine mounts, exhaust systems, carburetor-ice eliminators, oil systems, fuel systems, controls, accessories, and so on. No attempt is made to describe any particularly new ideas in engine-installation design, but rather the paper explains the fundamental requirements for satisfactory operation of Wright air-cooled aircraft engines.
1936-01-01
Technical Paper
360131
H. E. Buc, Edwin E. Aldrin
TO describe a new high-antiknock fuel that is well suited for the modern high-output aircraft engine and potentially available in large quantities, is the object of this paper. The high-octane blending agent used is isopropyl ether. Results of full-scale multicylinder engine tests with this material and iso-octane each blended with aviation gasoline to give a 100-octane fuel with 3 cc. of tetraethyl lead, and with iso-octane blended with aviation gasoline to give a 92-octane fuel with 3 cc. of tetraethyl lead, indicate that: Minimum specific fuel consumption of the isopropyl-ether 100-octane blend is lower under cruising conditions than the 92-octane, but higher than the 100-octane, iso-octane blend; the lower economy of isopropyl ether may be overcome by going above 100-octane number; and the 100-octane blends of isopropyl ether and iso-octane are equal in power output and consumption under high-power conditions.
1936-01-01
Technical Paper
360130
Macy O. Teetor
CYLINDER temperature is definitely one of the many important factors affecting the efficiency and life of an internal-combustion engine. Experience has indicated that cylinder temperature can be too low or too high. Each temperature extreme produces its own particular set of evils, but the high temperatures are the most destructive and the most difficult to control. Cooling-water or fin temperature is only slightly indicative of the cylinder-surface temperatures. Since we are most vitally interested in the temperature of the working surfaces, research on the subject must start on the inside. The evils of thermal distortion are well known but probably not fully appreciated. Practically every factor of engine performance is dependent upon lubrication. Excessive cylinder temperature destroys lubrication which, in turn, eventually shortens the life and decreases the efficiency of an engine.
1936-01-01
Technical Paper
360128
J. M. Orr
PROGRESS that has been made in the study of industrial accidents, covering factors that are involved in accident prevention in the operation of small cars and trucks and auxiliary equipment, is discussed in this paper. This paper also deals with the driver viewpoint, giving statistical data and methods for determining responsibility, driver qualifications, and the like. The problem also is approached from the viewpoint of safety as affected by vehicle design, operation (without respect to the driver), and maintenance. In collaboration with Mr. Orr, Mr. Newton discusses the problem from the points of view of traffic direction, educational campaigns, driving practices, and highway conditions. He touches on the right types of advertising propaganda and vehicle-design factors; he also gives interesting statistical data resulting from vehicular inspections in various states.
1936-01-01
Technical Paper
360129
Hall L. Hibbard
1936-01-01
Technical Paper
360127
F. D. Klein
INCLUDED in this paper are: Comparative performance of various types of fuels in high-output, single-cylinder liquid-cooled engine, and comparative performance of 100-octane toluene blend and iso-octane blend relative to 92-octane Army method regular gasoline in full-scale engine with two-speed supercharger and normal compression ratio. Endurance tests scheduled in Cyclone and two-row Wasp with 8:1 compression ratio and very low specific fuel consumption. Military present and contemplated future use of this fuel and its commercial possibilities. Possible means for increasing available supply. Availability of unleaded high-antiknock fuels and leaded fuels superior to 100-octane fuel.
1936-01-01
Technical Paper
360126
Lloyd Withrow, Gerald M. Rassweiler
PREVIOUS studies of flame propagation in a gasoline engine have suffered from the handicap that only a partial view of the combustion space was obtained. This disadvantage has now been overcome by covering the whole top of a single-cylinder ell-head engine with a quartz plate so that an unobstructed view of the combustion-chamber is allowed. To record, at known intervals, the progress and shape of the flame fronts a special camera has been built which photographs 30 individual pictures of a single explosion. Simultaneously, a pressure-time card is recorded. The interval between pictures is 2.4 crankshaft degrees; consequently, 5000 pictures per sec. are photographed at an engine speed of 2000 r.p.m. These photographs may be studied individually or projected as “slow-motion” movies which show the ignition spark, the spread of the flame through the charge, and the gas movements behind the flame. Pictures of non-knocking and knocking explosions are presented.
1936-01-01
Technical Paper
360141
Austin M. Wolf
1936-01-01
Technical Paper
360140
R. L. Hershey, J. E. Eberhardt, H. C. Hottel
THE thermodynamic analysis of an internal-combustion engine, even in the idealized case, is in general more complex than a similar analysis of an engine cycle in which the fluid undergoes no chemical change. It is the purpose of this paper to show that, despite the inherent complexity of the problem, an exact solution by graphical methods is possible, and the method is very similar in nature to those used in connection with the Mollier diagram for steam. Two types of charts are presented, one descriptive of the thermodynamic properties of the airfuel mixture (and residual products of combustion) before combustion, the other descriptive of the properties of the equilibrium mixture after combustion. Full allowance is made for the variation of specific heats with temperature and for the complex dissociation at the high temperatures attained after combustion. All calculations are based on the most recent basic thermodynamic data available in the literature.
1936-01-01
Technical Paper
360139
H. M. Jacklin
PRESENTING the analysis of several thousand observations of the reactions of humans to vibration when sitting on a controlled vibrating seat or platform and in moving vehicles. Physical reactions are defined carefully as a result of many experiments under controlled conditions. The perfection of a three-directional wave-recording accelerometer is described. Its use in determining vibration conditions when the defined physical reactions occur is displayed. The relative effects of vibration in three directions on hard and upholstered seats are disclosed together with suggested instrumentation with the accelerometer. The rating of vehicles of transportation by a comfort scale is easily accomplished by the use of the accelerometer.
1936-01-01
Technical Paper
360138
Fred W. Herman
THE introduction to this paper includes definitions of the major items under discussion, and is followed by a discussion of the materials most widely used in metal-aircraft construction and their important physical properties. In the remainder of the paper are described some of the problems encountered in metal construction and the processes that have been developed to facilitate manufacture. The following specific items are discussed: (1) Design, (2) Tooling, including lofting, (3) Fabrication, (4) Assembly, (5) Inspection, and (6) Protective coating. Special equipment and tools are illustrated.
1936-01-01
Technical Paper
360137
George R. Cunnington
THE noise problem in the automobile body is complex and encompassing due to the fact that no single angle of attack is either complete or by itself sufficient to produce the desired results. Such results must be in the final analysis appreciable to the passenger's ear. For practical purposes and to meet the requirements of the industry, the problem has been divided into two parts: (a) To secure better results or greater improvements, for the same cost or less, by finding the best materials suitable in the general body-insulation practices of today. (b) To secure a complete and well-balanced job, involving a broader application of materials found to be most practical and economical, or to develop unusual products possessing unusual properties and larger capacities to function properly under given conditions. The instruments and very thorough method used are just means to an end, as in other fields of research or experimentations in which so many here have played a part.
1936-01-01
Technical Paper
360136
John S. Parkinson
OF all problems involving noise measurement, the human ear is the final judge and the court of last resort. In most situations, as in the case of the motor-car buyer, it is the untrained ear of the average customer that ultimately passes judgment. Likewise in all instrument calibration, it is necessary in the final analysis to depend upon the ear as a basis. For this reason the measurement of noise must be so conducted that results and predictions will agree with ear judgments. A discussion is given of the various characteristics of noise that the ear recognizes, that is, loudness, pitch, quality, and discomfort or annoyance. The physical quantities corresponding to these psychological characteristics are discussed, and also methods of converting from one set of quantities to the other. The experimentally established relationships between pitch, loudness, and annoyance are given.
1935-01-01
Technical Paper
350122
Maurice Platt
1935-01-01
Technical Paper
350123
Donald H. Wood, Carlton Kemper
THE development of an N. A. C. A. cowling giving a low drag and satisfactory engine cooling for a particular airplane and engine installation requires the construction and flight testing of numerous experimental cowlings. An investigation has been undertaken by the National Advisory Committee for Aeronautics to determine a rational basis for the design of the N. A. C. A. cowling. The effect of front and of rear openings and of inner and outer lines of the cowling on the quantity of air flowing through the cowling, the pressure drop, and the drag have been determined from tests of models in a wind tunnel. The quantity of air and the pressure drop required for satisfactory cooling of a given design of air-cooled cylinder have been determined from tests of a single-cylinder engine. The results obtained from the tests of the models and the single-cylinder engine are being checked in a large wind-tunnel using a 550-hp. radial-engine fitted with a propeller.
1935-01-01
Technical Paper
350124
John Sneed
THE author gives results of several years' experience in the development of automatic transmissions. Early designs are shown and explained and reasons for changes to present designs are given. Driver reaction to different types of automatic shifting is discussed and conclusions are drawn. Graphs are presented showing the acceleration characteristics of different jobs. A detailed description of the author's latest development in fully automatic transmissions is given.
1935-01-01
Technical Paper
350125
F. P. Spruance
EXTENDING the life of those parts most quickly destroyed by corrosion, an important problem in the automotive industry, for practical purposes resolves itself into preventing the failure of paint on metal surfaces. The porosity of the paint films permits moisture to get through to the metal, and thus to induce electrolytic rusting. Chemically cleaning before painting retards paint failure. Coating the metal with phosphates gives better protection still, by permitting thicker coats of paint. This phosphate surface is not ductile, though, and breaks when the metal is bent, causing paint failure. Best protection is obtained by first plating the steel with zinc and then converting this plated surface into a zinc phosphate, so that the paint will adhere to it. The next best method is plating steel with a continuous coating of zinc phosphate by means of alternating-current electrolysis.
1935-01-01
Technical Paper
350107
Guy E. Beardsley
THE basic idea of accomplishing both a power limitation and a control of the mixture with one unit was evolved by the late Thorp Hiscock. He proposed, by throttling the air entering the carburetor, to maintain the density of air entering the venturis equivalent to that at an altitude of 7000 ft. Thus the carburetor would virtually be held at 7000 ft. and would deliver, even though the airplane might be at sea level, a mixture of the same fuel-air ratio that it would normally deliver at 7000 ft. Details of the development of the automatic power and mixture-control unit are given, together with descriptions of tests made and statements of results obtained. In conclusion, it is stated that, from the reports available on general fuel consumptions, it is apparent that some method of control is desirable.
1935-01-01
Technical Paper
350106
J. O. Eisinger, D. P. Barnard
IT is recognized that volumetric efficiency-and therefore specific output - can be increased by reduction in manifold temperature, pressure drops, and the like. The present investigation has been directed at the determination of the changes in volumetric efficiency which may be obtained by fuel-volatility variations. The results of this work may be summarized briefly as follows: (1) Very substantial improvement in engine performance can be obtained by taking advantage of suitable volatility increases. (2) A given degree of improvement in the distribution characteristics of a fuel can be attained by combining “front-end” and “total” volatilities in a fairly varied manner. (3) The distribution characteristics of a gasoline can be judged satisfactorily by using the amount evaporated at 158 deg. fahr.
1935-01-01
Technical Paper
350109
W. S. James, H. E. Churchill, F. E. Ullery
IN this paper the authors present some experimental results obtained by using the analysis outlined by Prof. James J. Guest before the Institution of Automobile Engineers, in 1926. To make the experimental work more understandable, they present the essential points of Professor Guest's analysis. Professor Guest begins his analysis of the movements of a car body with the simplest set of conditions and presents a graphical as well as an algebraic solution. He then includes one additional factor after another in his analysis until the principal factors in car suspension are included. After all factors are considered, the essential structure of the simple analysis is retained. The authors' efforts at the experimental determination of the moment of inertia of passenger cars were started in January, 1932, on Sir Charles Dennistoun Burney's “tear-drop” design with which he visited leading American manufacturers.
1935-01-01
Technical Paper
350108
John M. Campbell, Wheeler G. Lovell, T. A. Boyd
SINCE the design of the automobile engine depends largely upon the volatility and knock rating of the gasoline fuel it uses, a major problem is the fitting of the engine to these two fuel-characteristics. Regarding volatility, the engine must take the best advantage of the present available fuels; its design cannot be entirely made to suit an average gasoline; and, once an engine has been built, it must operate and give satisfactory service over a considerable period of years. Recent trends in important items of design are noted, as well as the trends to automatic chokes and warm-up controls. The author states that a system of classifying gasolines in terms of volatility is needed, and discusses various aspects of the starting problem. Other features include comments upon the trends in mixture temperatures, acceleration, crankcase dilution, and vapor lock.