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Viewing 191101 to 191130 of 193735
1939-01-01
Technical Paper
390124
W. E. Zierer, J. B. Macauley
SYMPATHIZING with the engineer who finds that the high efficiency designed into his engine fails to produce the anticipated increase in average miles per gallon obtained under normal driving conditions, the authors touch upon some of the factors, many of them out of the engine designer's control, which may completely mask the expected improvement. In so doing, they start with an engine of known specific consumption and show the effect of air resistance, chassis friction, gear ratio, and car weight on constant-speed road economy, comparing calculated values with actual test values available. Also discussed are such factors as climatic variations, traffic operation, cross-country driving and the individual driver, which have a definite effect upon economy, but over which the designer has little or no control. The effect of these factors is illustrated by the spread in tank mileage shown by a number of cars of similar model in fleet operation.
1939-01-01
Technical Paper
390125
Ulric B. Bray, C. C. Moore, David R. Merrill
THE most striking improvements in lubricating oils for automotive-type Diesel engines have been obtained through the use of soap-type additives, the authors contend, and several brands of this compounded oil are now available to Diesel engine operators. The paper deals particularly with this type of addition agent and reviews the improvements obtained through its use. Using such an oil, compounded with the calcium soap of dichlorostearate acid, the authors claim that five of the six properties considered necessary for a Diesel-engine crankcase oil are exhibited, namely-detergency which aids in preventing ring-sticking; high film strength which reduces the danger of scuffing, scratching, or galling under severe conditions; a high degree of oiliness which reduces wear under normal operating conditions; low carbon-forming tendency; and adequate crankcase stability which promotes cleanliness of the engine and maintains lubrication efficiency.
1939-01-01
Technical Paper
390123
A. T. McDonald
DATA are presented to show that compounded lubricants for use in the lubrication of high-speed Diesel engines have come to be regarded as indispensable, and to demonstrate their influence in high-temperature operation on engine deposits, oil deterioration, and strength and corrosion of bearing metals. The author divides filters into two general classes: the adsorbent type and the absorbent type. Adsorbent filters, the paper explains, incorporate in their composition Fuller's earth, charcoal, or other adsorbent materials and attempt to incorporate features which have as their object the refining of oil. Tests are described, the results of which lead the author to the conclusion that such filters remove addition agents used in compounding Diesel engine lubricants to a surprising degree and, therefore, are detrimental in such applications.
1939-01-01
Technical Paper
390122
F. L. Haushalter
INTENDED primarily to discuss rubber as a load-carrying and structural material, and not for suspensions in particular, this paper points out why it is best to limit the stresses and strains in the rubber structure to definite values when applied in this manner. As an aid to this end, attention is given to latex, raw rubber, and the structure of rubber, theoretical and otherwise. The limitations for the proper use of rubber are determined by long-time creep or slip in the structure which, in turn, is related directly to the magnitude of stress and distortion in the material, the paper states. Vulcanized rubber is practically incompressible, the author explains, and therefore, when properly confined, it can be loaded safely to terrific pressures just like any fluid.
1939-01-01
Technical Paper
390128
J. B. Johnson
MAGNAFLUX testing has become an important adjunct in connection with the inspection of aircraft parts fabricated from magnetic materials. The method is very sensitive and may indicate not only defects which seriously weaken the part, but also non-injurious imperfections. The author has classified the several defects indicated by magnaflux which have been found in the routine inspection and examination of a large number of parts which have been in service in engines, airplanes, and accessories operated by the U. S. Army Air Corps.
1939-01-01
Technical Paper
390132
A. H. Leak
IT is necessary to develop designs that can be manufactured readily to keep down costs. This policy benefits the industry generally, and it is also necessary to meet domestic and foreign competition. Close attention to the following items is necessary to produce and maintain satisfactory production designs: 1. Carefully developed design and test programs are essential to develop advanced engines and details by orderly and logical processes. 2. Standardized engineering and drafting practices are a necessary part of any engineering organization to maintain drawing consistency. 3. Close cooperation between production and engineering departments, starting with the original design and manufacture of experimental parts, is particularly important. 4. The utilization of developed units and parts on new models when practicable. The desirability of reducing the total quantity of different parts made is evident to facilitate manufacture and servicing. 5.
1939-01-01
Technical Paper
390126
E. S. Ewart
1939-01-01
Technical Paper
390127
B. A. Yates
THE importance of the material of the piston ring has too long been relegated to the background as compared with such design factors as ring proportions, ring loadings, circularity, point pressure, and so on; therefore, this paper concentrates on the material factors - such as composition, structure, and surface finish - which should go into the modern piston ring. The causes of piston-ring wear are analyzed and classified under three headings - abrasion, corrosion, and erosion. Various types of coating materials, both metallic and non-metallic, employed to reduce the severity of scuffing or scoring, are considered. Test results are revealed that indicate that superficial coatings reduce piston-ring wear from scuffing and erosion, and that a very thin coating of tin was more effective than other types of metallic and non-metallic coatings.
1939-01-01
Technical Paper
390169
Joseph S. Newell
1939-01-01
Technical Paper
390168
M. G. Beard, E. W. Fuller
THE feathering propeller meets two fundamental needs in airline operation which the constant-speed propeller cannot meet, the authors explain. First, by stopping the rotation of an engine and propeller in flight, it protects the airplane from catastrophic vibrations occasionally set up by mechanical failures of engine and propeller. And the second fundamental need, they state, is that the feathering propeller decreases the drag of an inoperative propeller, thereby increasing the performance of a multiengined airplane with one or more engines inoperative. For these reasons, they point out, the feathering propeller has been accepted by leading airlines as the answer to their immediate propeller needs. In this paper the full-feathering principle is explained as applied in two distinct propeller designs.
1939-01-01
Technical Paper
390166
M. J. Kittler
NEITHER severe military maneuvers, such as power dives and inverted flight, nor icing conditions will affect appreciably the operation of the aircraft carburetor described in his paper, Mr. Kittler asserts. To back his claim, he points to over 1½ years experience with several hundred of these carburetors since the start of their development in 1935. After a discussion of the problems of icing, maneuverability, and metering, the author details the construction and operation of the type of carburetor finally developed. This carburetor is unlike commonly known types, he explains, in that the fuel level is controlled by a double-diaphragm mechanism instead of by the conventional float mechanism. In place of the fixed venturi and butterfly throttle construction is a variable-venturi mechanism which forms both the throttles and the venturi. Metering is governed, Mr.
1939-01-01
Technical Paper
390167
Edwin L. Allen
THE development in constructional design which appears to be nearest at hand is the so-called unit construction, Mr. Allen believes. Rear-engine mounting is inevitable, he reasons, if cars are to become more blunt of nose and more tapered at the tail, but the change-over will evolve slowly. Speculating on future body materials and processes, he first takes up the possibility of molding the complete body in large sections of some plastic material, giving his views on the improvements that must be made in the plastic materials and necessary changes in production equipment and processes. The three major periods - past, present, and future - are considered separately in the light of their influence upon: 1. The body engineer himself, his development, his ever-changing responsibilities and opportunities. 2. Constructional design and probable reasons for adopting each successive type of construction used. 3. Styling and contour changes, illustrating trends affecting outward appearance.
1939-01-01
Technical Paper
390164
A. W. Bull
DR. BULL emphasizes the vital role that tires play in car stability, not only because they provide the final connecting link between car and ground forces, but also because they have inherent properties which are indispensable to safe and smooth steering control. Stability, however, is a relative matter, he explains, as the skill and experience of the driver enter into the problem to a very considerable degree. Although the factors in car or chassis design which affect stability are numerous and complex, this discussion deals only with that portion of the problem which relates to the behavior of tires under the different conditions to which they are subjected. That stability is far from uniform among tires of different manufacture, and that speed has very little effect on cornering force under practically all conditions, are two of the conclusions reported from experiments made on a test machine built especially for studying the behavior of tires under a wide range of conditions.
1939-01-01
Technical Paper
390165
Ernest F. Davis
THE control of grain size has facilitated the development of new steels and modifications in heat-treating processes, Mr. Davis announces. His paper deals with modern progress in the steel mill, the employment of the Carbometer and Turbidimeter, lime-silica ratio and the newer deoxidizers employed to aid steel quality. The internally heated immersion bath has been a distinct advancement in salt-bath hardening and enables longer pots to be practical, he explains. Dry cyaniding with ammonia gas may eventually obsolete cyanides and activated baths, in the opinion of the author. Gas carburizing gradually is supplanting box carburizing, he reports, and many large heat-treating units carburize, quench wash and temper mechanically. Also, a late gas carburizing furnace eliminates the employment of a muffle.
1939-01-01
Technical Paper
390162
Don R. Berlin, Peter F. Rossmann
AS a refinement that permits a smoother external or wetted surface of the airplane, and thus adds to aerodynamic cleanness, flush riveting of the plane's skin is of utmost importance, Mr. Berlin points out. The ultimate object of the research reported, he explains, was to outline the problem of determining and providing requisite tools. No attempt is made in his paper to treat the aerodynamics and strength characteristics of flush riveting. Among the phases of riveting that required careful analysis in the solution of the problem noted especially by Mr. Berlin are appearance, strength, processing methods, economics of production and sources for equipment and tools. Time studies were employed extensively, and close contact with the production departments was maintained in the work.
1939-01-01
Technical Paper
390176
Donald B. Brooks, Robetta B. Cleaton
ON May 4, 1936, at the meeting of the CFR Detonation Subcommittee 1, the National Bureau of Standards presented the “Supplementary Report on Analysis of Detonation Rating Data,” which completed the first analysis of the Cooperative Exchange samples. This analysis 2 included the “first” and the “E” series of tests of Uniontown (1934) fuels and the first 67 Cooperative Exchange samples. At the CFR Motor Fuels Section 1 meeting on Nov. 7, 1937, the Bureau was requested to make a second analysis of the Cooperative Exchange fuels since June, 1936. This analysis is based on results of 6386 tests on 136 fuels. These tests were made by over 100 laboratories including laboratories of the CFR Exchange Group and a non-member group, with laboratories in foreign countries, invited to participate semi-annually.
1939-01-01
Technical Paper
390163
H. O. Mathews
ABSTRACT
1939-01-01
Technical Paper
390178
A. S. Krotz
THIS paper deals with one system of designing rubber springs; outlines its advantages; indicates its limitations; and describes the approach to the problem. This spring is of the torsion type, called “Torsilastic,” and is claimed to present advantages not only in its characteristics as a spring but also in flexibility of application which makes it possible to meet a wide range of requirements by variations in spring design and in the length of the moment arm which applies the torsional load. In general, it consists of an inner shaft surrounded by an annular layer of rubber bonded to the inner shaft and also to an outer metal shell. The outer shell is split into two segments. The spring is stressed in torsion by anchoring either the shaft or outside shell to the chassis and rotating the other member.
1939-01-01
Technical Paper
390174
W. Spannhake
THE designation, “hydrodynamic” power transmission, is used in this paper, and not “hydraulic” power transmission because fluid gears are discussed that operate by dynamic action like turbines or centrifugal pumps, not those working by means of static fluid pressure like piston pumps. It is the dynamics of turbines and centrifugal pumps which has to be understood when the action of a hydrodynamic gear is to be explained. The basic ideas of the hydrodynamic power transmission are given, especially when applied to motor cars. A hydrodynamic gear which can take differences of torque between the primary and secondary shaft and which consequently is furnished with one or more fixed blade rows, is defined as a “hydraulic torque converter,” but such a gear, which consists of revolving blade rows only and, therefore, cannot take differences in torque is called a “hydraulic coupling.”
1939-01-01
Technical Paper
390175
Edmund T. Allen
THE organization, training, attitude, and esprit of the crew are all-important for successful flight-testing of large aircraft, Mr. Allen shows. These problems, he explains, are similar to those involved in the functioning of a military unit or of a city government. Choosing the required personnel of from 3 to 10 men fitted to their various duties, training and coordinating them, and building up an efficient unit for collecting accurate flight-test data under conditions of hazardous operation devolves upon the chief test pilot. Since flight-testing involves continuously extending the range of investigation of flight characteristics toward margins of safety, the principle of least hazard has been developed to guide all flight planning and all test operation. This least-hazard principle guides the testing of structure and functional systems through the initial flights, stability tests, performance tests, and flying qualities determination.
1939-01-01
Technical Paper
390172
Paul S. Lane
PISTON-RING irons are not the “best-wearing” irons, contends Mr. Lane in his discussion of bore wear from the standpoint of the materials commonly used for high-speed automotive diesel and aircraft-engine cylinders, liners, and rings. Measured on a weight-loss basis under direct comparison with other conventional iron structures, piston-ring irons normally give relatively high weight-loss figures. But piston-ring irons do have the significant and desirable faculty of wearing away with very little tendency to accumulate wear products on their rubbing surface. In fact, this ability is probably of equal or greater importance than actual low weight loss. In his paper Mr. Lane reports the results of several years of laboratory wear-testing research, correlated in many instances with actual service experience, from the viewpoints of hardness, structure, and chemical composition.
1939-01-01
Technical Paper
390173
T. A. Boyd
CALLING knock “the cancer of engine combustion,” Mr. Boyd explains that his paper- a review of research on engine combustion which has been pursued steadily for many years - is concerned chiefly with this phenomenon. Of the many aids to observation which have been developed for the research, or adapted to it, he describes first an optical engine indicator by means of which it was observed early that knock is not caused by preignition, as was then thought, but that it arises from a pressure disturbance which occurs several degrees after the ignition spark.
1939-01-01
Technical Paper
390170
F. R. Banks
FUTURE engine developments for powers between 2000 and 4000 bhp and the author's views on the form which such engines will take, together with optimum cylinder sizes and number of cylinders, are covered in the latter part of Mr. Banks' paper. Because it concerns the possible future development of military aviation in America as well as his own Country, the author considers this part the important one. In the first part, he gives a short résumé of the aviation fuel position in Great Britain, and then goes on to describe some work which he has done in conjunction with the British Air Ministry and one of the aero engine manufacturers on very high-duty aviation engines. He also discusses what, in his opinion, is a characteristic of the American two-valve hemispherical cylinder head relative to British four-valve engines in regard to fuel behavior. He continues, mentioning certain new developments, such as the treatment of poppet type exhaust valves with Brightray.
1939-01-01
Technical Paper
390171
Albert C. Reed
THAT large airplanes, and the DC-4 in particular, pay their way in air-transport service, especially for long ranges over 400 miles, is indicated by the flight-test data reported by the author. The 1000 individual tests made on the DC-4 during 74 flights occupying 90 hr were made for stability, control, operation under extreme conditions, and performance. This 65,000-lb four-engined landplane with a wing span of 138¼ ft and an overall length of 97 ft, Mr. Reed explains, originally was conceived by agreement between the Douglas Co. and five major airlines: United Air Lines, Transcontinental & Western Air, American Airlines, Eastern Air Lines, and Pan American Airways.
1939-01-01
Technical Paper
390185
Charles M. Kearns
COMPLETE isolation of the airplane propeller from the engine, except for a very flexible torque drive, appears to be the only satisfactory solution of the vibration problem in the future, Mr. Kearns believes. Under such conditions, he explains, much lighter propeller blades can be used to maintain even greater horsepowers than are available at present so that, in spite of the trend toward more power, the increase in overall weight of the powerplant may be delayed considerably. This problem of the vibration characteristics of the engine and propeller when operating jointly, he points out, recently has become practically the determining factor in the selection of the proper propeller for use with a given airplane-engine combination. An intensive investigation of this problem, studying both experimental and analytical approaches to the causes and solution of the high-stress conditions found in some engine-propeller combinations, is reported. In his paper, Mr.
1939-01-01
Technical Paper
390184
W. D. Appel
MR. APPEL defines a frameless car as one in which the body is used as a structural member and in which the axles, engine, and steering gear are attached to the body, instead of having that unit used merely as a shell for passengers. The chief differences between frameless and conventional cars are summarized by stating that frameless cars: 1. weigh about 2% less; 2. cost less by somewhat more than 2% - where sufficient quantities are involved; 3. are definitely more rigid; 4. are necessary to obtain the lowest floor height; 5. cost no more to service; 6. are just as quiet on the road; and 7. do not involve higher insurance rates than conventional cars.
1939-01-01
Technical Paper
390183
Frank Jardine, A. H. Woollen, D. S. Mussey
BY the use of carefully considered designs, the authors contend, any transportation unit in use today can be made largely of aluminum and considerably lighter than the same unit made entirely of ferrous materials. In most cases, they declare, it is possible to make a weight reduction of approximately 50% from the weight of an iron or steel part when aluminum is used. Results of a test made on a 36-passenger aluminum-alloy bus are reported, indicating that calculated stresses do not correspond very closely with measured stresses. This finding is attributed to the fact that a bus body is a complex, statically indeterminate structure and the accuracy of design calculations is wholly dependent upon the accuracy of the assumptions upon which they are based. Strain gages were used to measure the stresses actually occurring in the parts.
1939-01-01
Technical Paper
390182
Albert B. Willi
SIX major causes of bearing failures are catalogued, which include matters of engineering and design, procurement practices, misuse and abuse in operation, faulty installations, unsuitable lubricants, and mechanical faults in the bearings themselves. Although there are four general types of bearing materials in common use today for main and rod bearings - tin-base babbitts, high-lead babbitts, cadmium alloys, and copper-lead mixtures, the author shows that not one of them is a universal bearing material - each has its own particular field of usefulness, and these fields are defined in terms of maximum unit pressure, Zn/P, PV, oil-reservoir temperature, and crankshaft hardness. Design factors that react against indicated satisfactory performance are considered, including strength and stiffness of the bearing structure, oil flow to the rod bearing, restrictions in feed grooves, oil clearance, and so on. Standards of design pertaining to these points are set up.
1939-01-01
Technical Paper
390181
Arthur Nutt
MR. NUTT outlines the recent progress in the development of aircraft engines by a brief review of the progress made during the past 10 to 15 years. He explains some of the design details which have aided in this progress. The various design features are discussed to emphasize the importance of detail research and development. Among the items of importance are cooling, supercharging, vibration damping, fuels, materials, and spark plugs. Included in the paper are discussions of the trends in fuel injection, compression-ignition engines, co-axial propellers, liquid-cooled engines, engine types, sleeve-valve engines, lubrication, and the relative progress in the development of American and European engines. Although this Country is not lagging in its technical ability to produce high-output engines, the author cautions that we must continue to provide adequate funds and personnel if we are to maintain a satisfactory position in the industry.

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