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1926-01-01
Technical Paper
260059
C. S. STARK
An instrument that utilizes the principles of radio amplification for inspection purposes is described and the experience that led to its development is recounted. It measures the finish polish on metal pieces by light from a microscopic lamp reflected from the surface upon a photoelectric cell, or amplifying bulb, that responds instantaneously to minute variations of light intensity and is connected in a suitable amplifying circuit to a milliammeter. The elements comprising the instrument are enumerated and the circuit diagram used is explained. As the instrument provides a method primarily of comparison, a standard value of the light reflected from a surface of the desired finish is established and the finish of parts to be compared is read from deflections of the milliammeter needle above or below this standard. The purpose of the instrument is to supplant by an accurate mechanical means the uncertain judgment of an inspector who relies upon the physical sense of vision.
1926-01-01
Technical Paper
260060
E. E. WILSON
The purpose of the paper is to point out the basic policies which have resulted in the fostering of air-cooled-engine development by the Navy, and to indicate where the development has led. Two roles played by naval aviation are designated “air service” and “air force.” The former term refers to the functions of naval aircraft which are contributory to the ships of the fleets, such as scouting and the control of gun-fire. The latter term refers to the functions which involve the use of aircraft as an integral and component part of the Navy's striking force, such as combat, bombing and torpedo launching. Seven different types of aircraft are required by the Navy for its different purposes, these being airplanes for training, fighting, observation, scouting, torpedoing, bombing, and patrol use.
1926-01-01
Technical Paper
260064
ARTHUR W. GARDINER
Development of the aircraft powerplant has been the greatest single contributing factor to the progress of aviation. A logical field for future development seems to be the improvement of its altitude performance, and the best of the several proposed methods for doing this. Consequently, the Sub-Committee on Powerplants for Aircraft of the National Advisory Committee for Aeronautics recommended that the Roots-type compressor be investigated, and a complete supercharger was built and sent to the Langley Field laboratory for test. The design, principles of operation and characteristics of the Roots-type compressor are described, and its slip-speed due to air leakage past the rotors, its pulsating discharge, type efficiency, and variation in torque are discussed. The Roots-type supercharger built for the National Advisory Committee for Aeronautics, as designed for use with the Liberty-12 engine, is described and illustrated.
1926-01-01
Technical Paper
260063
ARTHUR NUTT
The marked advance that has been made in the last 10 years in constructional details and in performance of airplane engines and in airplane performance is reviewed, beginning with the year 1916 when the Curtiss OX-5 eight-cylinder water-cooled engine was brought to its final stage of development. The author describes briefly each type of engine produced successively by the company he represents and tells of the changes that were made to improve the performance. From the 8-cylinder V-type the constructors changed to the 6 and 12-cylinder water-cooled type and are now developing a 9-cylinder air-cooled radial engine that was built in 1925. An important field of usefulness is foreseen for the air-cooled engine.
1926-01-01
Technical Paper
260061
E. T. JONES
Confining his subject matter strictly to a discussion of the Wright Whirlwind engine and its bearing on the present status of the air-cooled aircraft-engine, the author says that the type of engine specified embodies in its development two distinct forms of cylinder construction, the first having been developed by Charles L. Lawrance and the second by S. D. Heron. The application of these cylinders to the engine under discussion is outlined and the subsequent development is traced. The development of the J-5 type of engine was undertaken in an effort to place the air-cooled engine fully on a par with the water-cooled type as regards fuel consumption. The cylinder is characterized by a hemispherical combustion-chamber employing two valves with axes inclined at 70 deg. The valve-seats are of aluminum-bronze shrunk into the cast-aluminum head. The cylinder-barrel with integral cooling-fins and hold-down flange is screwed and shrunk into the aluminum-head casting.
1926-01-01
Technical Paper
260067
Wesley L. Smith
The experiences of the author in flying over an air-mail route are graphically portrayed. Although general practices hold for all routes, each route is said to present its own problems; special methods used in flying between any two points are not entirely effective in flying between any other two points. Conditions along the New York City-Cleveland route are therefore described and such topics as lights and beacons, terminal fields, emergency landing-fields, and the various aids in locating the position of the airplane when the beacons are obscured, are discussed. Among these aids are the general appearance of cities and the direction of their main streets, large factories, blast-furnaces, amusement parks, lighted railroad trains, automobile headlights on main highways, railroad roundhouses, mountains, and rivers. In nightflying, much depends on the airplane, which must meet definite requirements.
1926-01-01
Technical Paper
260065
ADOLPH ROHRBACH
Reduction of cost and of the time required to construct airplanes and seaplanes by applying so-called shipbuilding practice to their fabrication, embodying late types of production methods, are discussed by the author, who says that the company he represents adheres to a number of technical principles to reduce to the minimum the risk of designing and constructing new types. The technical principles refer to general arrangement and to layout, as well as to the detail design of many parts of the planes. They include also very careful and minute preparation for the actual workshop construction by the supplying of perfect workshop-drawings and by proper organization of the technical departments. The paper outlines the technical principles, including reasons for their adoption, and then describes the organization of the work of construction. Wing-loading and power-loading are discussed, and the statement is made that the company builds monoplanes only.
1926-01-01
Technical Paper
260013
C W ISELER
Progress has been made steadily in the application of superchargers to racing automobiles, and the author of the following paper has no doubt that the supercharger will be adopted as standard equipment on passenger automobiles of the better class within the next few years. Builders of the Mercedes car have placed on the market two models regularly equipped with a supercharger of the Roots blower type, and the increased power, flexibility and speed of these cars have shown the public the great possibilities obtainable by the supercharger. In addition to the foregoing advantages, the supercharger gives greater mechanical efficiency and fuel economy.
1926-01-01
Technical Paper
260016
This subject is treated in a paper in two parts. Part I, by Alex Taub, deals with laboratory tests to prove by comparative data that the higher average operating-temperatures maintained in the engine by the constant-temperature, or evaporation, system of cooling have negligible detrimental effects. Part II, by L. P. Saunders, gives the results of road-tests of cars operated under the same conditions when fitted with a standard water-cooling radiator-core and with a constant-temperature cross-flow condenser-core. Although contamination of the crankcase oil by heavy ends of the fuel is not prevented by the higher temperature of constant-temperature operation, it is asserted that this higher temperature is effective in striking an acceptable balance in such contamination and results of the tests show that the cylinder-walls are maintained at temperatures sufficiently above the vaporization point of water to reduce the condensation of water vapor to the minimum.
1926-01-01
Technical Paper
260017
O T KREUSSER
Layout, facilities and activities relating to making road-tests of motor vehicles at the 1125-acre proving grounds of the General Motors Corporation near Detroit, this tract being designed to provide a place where road conditions are suitable for obtaining data that can be interpreted accurately, compared with similar data and used constructively, are outlined and illustrated. Adequate facilities are provided and ideal road-conditions have been established so that motor-vehicle tests involving endurance, speed, acceleration, hill climbing, riding-quality and other comparative tests can be made. Conditions are such that tests can be repeated from day to day, thus compensating for the variations of the weather and other factors. Complete and conclusive tests can be carried out readily and promptly, and the results are free from guesses and personal opinions. The speed track is 20 ft. wide and nearly 4 miles long. Traffic is in one direction, clockwise.
1926-01-01
Technical Paper
260022
WALTER D'ARCY RYAN
Subsequent to reviewing the circumstances responsible for the present complicated situation existing with respect to satisfactory automobile-headlighting, the author says that headlights glare if they are adjusted for range and that, when adjusted for non-glare, they have no range; hence, careful tests were made on a number of the best types of approved headlight and lens in use. The units were set-up in pairs, in operating position as to height and interval and were tested at a range of 100 ft. with a 1-m. (39.37-in.) hemisphere having an aperture 21 in. square, corresponding to 1 deg. at 100 ft. All the lamps were held at proper current-value throughout the tests, and it was demonstrated by the tests that the reflectors of the parabolic type and others of similar characteristics that have proved to be unsatisfactory during many years past must be abandoned.
1926-01-01
Technical Paper
260023
L C PORTER, G F PRIDEAUX
Since the layman and not the engineer buys and drives most of the automobiles produced and because the literature on automobile headlighting presents to[ILLEGIBLE] technical a picture of what happens when the light source of an automobile head-lamp is out of focus, the authors planned and executed an extensive study of the subject in an endeavor to clarify the technicalities by presenting them in the forms of photographs and simple charts, the chief object being to obtain data that emphasize the necessity of accurate control of the size and location of the light source with respect to the focal point of parabolic headlight-reflectors. A great difference in the resultant beam of light is produced by a very small displacement of the light source, either through poorly constructed lamps or due to lack of proper adjustment, and the tests made evaluate how small these displacements and how great these differences are.
1926-01-01
Technical Paper
260025
H F Parker
Although the generally accepted spheres of usefulness of the airship and the airplane are usually based on their comparative ranges of operation and their speeds, the suitability of either of these types for a given purpose is primarily dependent on two classes of factors, those fundamentally dissimilar and those roughly similar. Conclusions as to relative usefulness should be based on a consideration of the dissimilar characteristics, which include aerodynamic efficiency, size and comfort. Aerodynamic efficiency governs range and, since it determines fuel consumption, influences the cost of operation. The size required depends on the paying loads that are available for carrying. Comfort concerns passenger-carrying only. As the propeller efficiency, rate of fuel consumption and ratio of weight of fuel carried to gross lift are similar in both types of aircraft, the range must depend on the L/D factor, that is, the ratio of gross lift to thrust.
1926-01-01
Technical Paper
260032
T. S. SLIGH
Elementary theories regarding the evaporation characteristics of pure substances and mixed liquids are discussed briefly and the difficulties likely to be encountered in attempts to calculate the volatilities of motor fuels from data relating to pure substances or in the extrapolation of volatility data corresponding to the atmospheric boiling-range of the fuel to the range of temperatures encountered in utilization of the fuel are pointed out. A brief review of previous methods of arriving at fuel volatility is also presented. Volatility, as applied to motor fuels, is defined as being measured by the percentage of a given quantity of the fuel which can be evaporated under equilibrium conditions into a specified volume. The weight of air under known pressures is taken as a convenient measure of the volume. The new method described is an equilibrium distillation of the fuel in the presence of a known weight of air.
1926-01-01
Technical Paper
260034
W. G. WALL
Lubricating-oil, despite the abuse it receives, is expected to perform its function properly. Road dust, gasoline and water are allowed to mix with it, and it is subjected to a high temperature and mixed with carbon, so that the original oil soon becomes hardly recognizable. Some remedies that have been proposed provide for the removal of either the dirt or the dilution, but both should be kept out. Water not only dilutes the oil, but forms sulphurous acid, rusting the parts and, in winter, probably freezing at the oil-pump. When mixed with oil, it forms an emulsion and when this emulsion is mixed with road dust or carbon particles, sludge is gradually formed. Sludge, when agitated and sucked through the oil-pump, tends to clog the oil-holes and to wear the bearings. Oil, when exposed to a high temperature on the cylinder-walls, becomes oxidized and black in color. Sulphur in the fuel probably forms sulphur dioxide and, by mixing with water in the crankcase, becomes sulphurous acid.
1926-01-01
Technical Paper
260037
FERDINAND JEHLE
In undertaking any experimental work the first step is to plan carefully each successive step. Literature bearing on the subject should be examined to learn what work others have done on the problem and avoid needless duplication of effort. If the testing of only a simple accessory is involved, the results the device is intended to accomplish should be studied and an effort made to discover the designer's reason for believing that it will accomplish them. All conditions under which such a device must operate should be listed and the information needed from which to draw conclusions as to whether the device will meet them successfully should be determined. Before starting the actual work of testing, it is good policy to plan the necessary charts for presentation of the report. This preliminary work means that the investigator will start well prepared but not with his mind made up as to what the results will be.
1926-01-01
Technical Paper
260039
FRED S. DUESENBERG
Development of the two-cycle high-speed supercharged engine used in the Duesenberg racing cars that competed in the 1926 500-mile Indianapolis race is described. Excessive trouble in starting the engine, which requires considerably higher supercharger pressure than does the four-cycle engine, inclined the designer and builder to abandon the idea of using this type of engine in the race. The supercharger gear-ratio was not laid out for the extreme speeds and, as the engine speed is directly proportional to the supercharger pressure, the pressure was too low to give the desired speed. The speed and efficiency of the engine were increased by increasing the width of the cylinder intake-ports, but the author believes a supercharger pressure of 15 lb. per sq. in. is necessary for good operation. Best results were obtained when the rotary valve opened the intake valve after the exhaust ports had been opened about 3/16 in.
1926-01-01
Technical Paper
260042
L. R. BUCKENDALE
Progress in the development of automotive worm-gearing is interestingly outlined. Previously tO 1912, American experience had been limited almost exclusively to the industrial form, generally of the single-thread type. Introduction of the motor truck required a worm for the final-drive but one having entirely different characteristics from that of the industrial gear. Experience in designing these was lacking, however, as was also the special machinery to produce them. In 1913, machinery was imported from England and since that time development has been rapid. First efforts were devoted to simplifying the design of the axle as a whole, studying the problem of getting lubricant to the bearings, heat-treating the parts, and improving the materials of construction.
1926-01-01
Technical Paper
260043
G. H. ACKER
Subsequent to a brief review of the development of the worm-gear drive for motor-trucks and the gear-ratios considered most desirable, the author discusses comparatively the worm-gear and the spiral-bevel gear with regard to their application for specific service, as well as with regard to their cost and length of life. It is brought out that the worm-gear is, after all, very similar in action to any sliding, or journal, bearing. A certain amount of involute rolling-action takes place in the action of the gearing, the magnitude of which increases with the gear-ratio; but the primary action is one of sliding of the worm-threads across the gear-teeth. Simple as this fact is, the prejudice fostered by many people against worm-gears can be traced to lack of appreciation of it. Due to the nature of the surfaces in contact, the best obtainable bearing takes the form of a narrow strip running across the gear-tooth, and the bearing pressures obtained are high.
1926-01-01
Technical Paper
260009
D M PIERSON
Because of the great increase in the winter use of automobiles resulting from general highway improvement and a doubling of the percentage of closed cars produced in the last 5 years, the problem of satisfactory operation of automobiles at low temperatures has assumed far greater importance than prior to 1920. It has therefore become necessary to make a more intensive investigation of the difficulties encountered in winter driving and of means for their avoidance. Study of low-temperature operation on the road is unsatisfactory because of the many variables in the conditions and the sudden and extreme changes that occur; consequently a refrigerated laboratory in which cars and engines can be tested under constant conditions that simulate as nearly as possible those met in road driving in winter is highly desirable.
1926-01-01
Technical Paper
260052
Charles M. Manly, C. B. Veal
After quoting statistics that show the alarming increase in thefts of automobiles and analyzing numerous conditions under which automobiles are stolen, the authors discuss locks as theft retardants, saying that the providing and the improvement of locks has always been man's method of seeking security from thieves and comes in naturally for first consideration as the normal course to pursue in working toward adequate theft prevention. The present identification systems in use are mentioned, together with their features of advantage and disadvantage, and numerous practices that owners and drivers can adopt which tend to minimize theft are cited. The early forms of locking device are outlined and statistics are included which show the percentage of cars actually locked when they are equipped with a locking device.
1925-01-01
Technical Paper
250066
G J Mead
Infallible performance and economical operation are the bases of successful commercial flying. Airplanes, having passed through the experimental and demonstration periods, must now prove their usefulness. Heretofore, because of military requirements, designers have fostered the use of power rather than refinement of design to obtain performance, but commercial operation demands efficiency, and in each of the four essentials, namely, dependability, size, total powerplant weight and cost, opportunity for decided improvement still exists. The requirements and limiting factors of each of these essentials are discussed in turn and the conclusion is drawn that a relation exists between the amount of thrust delivered to the air and the weight put into an airplane for its propulsion. To obtain the best over-all performance, if these terms are considered as a fraction, the numerator should have the maximum and the denominator the minimum value.
1925-01-01
Technical Paper
250063
LOUIS RUTHENBURG
Industrial development has out-run foreman development, in the author's opinion. He believes that management should be alive to the changed status of the foreman and that it should train him definitely to accept a broader responsibility. Clarification of the situation should start with the assumption that the departmental foreman is to be held definitely responsible for every activity that affects his department; but, obviously, he cannot be given direct authority over certain functionalized services that very directly affect the operation of his department, and he must, therefore, develop that higher type of executive ability which can obtain results without the club of direct authority. In short, instead of conceiving the departmental foreman as the master craftsman of his department, he should be looked upon as the business manager of his department.
1925-01-01
Technical Paper
250062
LILLIAM M GILBRETH
Successful production demands the greatest volume of output with the least amount of effort. It is of prime importance in industry, and its slogan is the elimination of waste, considering always the worker, surroundings, equipment and tools and the methods or motions used. Therefore, it is necessary to give attention to training employes in production work. The paper evaluates training in terms of production and formulates the elements that have proved effective, the aims of such training being to develop a better worker in the particular job, to produce a better member of industry and to create a better member of society. The worker always must be judged with relation to his work, and no more important psychological test exists than that of aptitude for the job.
1925-01-01
Technical Paper
250059
W G Careins
The selection of machine-tools is largely a matter of judgment, based on the consideration of many variable factors. No fixed rules can be laid down, but the uses to which the machines are put are divided roughly into three classes which govern to a large extent the types of machine that should be purchased, whether they should be machines of a wide range of usefulness, standardized machines equipped with special tooling or special-purpose machines of special design capable of very large and continuous production. To determine into which of these classes the requirement for new machines falls, an analysis should be made of the following factors: (a) quantity of production required and its duration, (b) method of machining and tolerances and finish required, (c) possibility of a change in design of the product, (d) cost of production, (e) when delivery of machine is required, and (f) money available for the purchase.
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