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Viewing 12751 to 12780 of 13367
1933-01-01
Technical Paper
330003
A. L. MacClain, D. S. Hersey
THE purpose of this paper is to show that the value of commercial flight-testing depends largely upon the utility, reliability and accuracy of the equipment and instruments employed. In general, it is found that improvements in these three factors depend largely on the simplicity of the apparatus used. Special engine-tests have led to the development of instruments and apparatus not commonly available commercially, and the use of these has made it possible to employ the aircraft engine as an instrument for the measurement of power in flight. This ability to measure power has led to the development of a method of making comparative engine-temperature and other tests which eliminates or corrects for a number of the major variables ordinarily affecting such tests. Because of the increasing popularity of the controllable-angle propeller, tests are also described which enable one to determine the value of such a propeller when only an adjustable-angle propeller is available.
1933-01-01
Technical Paper
330001
E. J. W. RAGSDALE
Railroads are facing a crisis in operating costs, the urge toward reduction of unnecessary weight has become widespread and the crusade for noise abatement is no longer to be denied, according to the author. The pneumatic-tired railroad-coach not only answers these requirements, he says, but anticipates a demand for a new traveling comfort. The desire to rubberize railroad equipment is old but much fruitless research has resulted from directing it chiefly toward solid-rubber or cushion tires. Road and rail surfaces present entirely different problems so far as the tire is concerned. No uniformity of conditions obtains on highways but rails are even and smooth. A badly aligned joint such as would wreck a metal wheel makes no impression on a pneumatic tire. As simple as the tire problem may seem, its solution represents years of courageous and skillful research on the part of the Michelin company in France.
1933-01-01
Technical Paper
330030
J. A. Roché
THE purpose of this paper is to pass on to airplane designers the things that have been learned in the last year about flutter and vibration of structures to which control surfaces are attached in order that, benefiting by all experience available, this great source of danger in new designs may be controlled. Test pilots also should be interested in this subject because it may help them in deciding proper action when a case of flutter is encountered and to recognize vibrations which may lead to destructive flutter. The present-day methods of stress analyses, imperfect though they are in certain respects, and the design load-factors in current use are adequate to provide all the strength needed in airplane structures for flight in rough air, and for all necessary maneuvers. A review of structural failures in the air reveals the fact that a resonant vibration was in nearly all cases responsible.
1933-01-01
Technical Paper
330031
AUSTIN M. WOLF
1933-01-01
Technical Paper
330026
F. A. Moss
(ABSTRACT) Dependability, economy, durability, speed, safety, appearance and riding comfort, are the factors considered by Dr. Moss in his resume of progress made in automobile development. Passing then to the problem of the effect of automobile riding on the health of passengers and drivers, he discusses air conditioning, eye strain and body posture while riding. Carbon monoxide probably is the most important of the extraneous harmful substances in relation to air conditioning and an inexpensive investigation, using a carbon-monoxide indicator, is recommended to secure its elimination. Other harmful factors are temperature, relative humidity and motion of the air. A novel suggestion is made that rats be used experimentally in studying the effects of drafts on passengers. Studies to lessen eye strain and improve body posture are also desirable.
1933-01-01
Technical Paper
330027
O. D. Treiber
1933-01-01
Technical Paper
330010
Walter C. Keys
THE TERM “automatic transmission” is defined as meaning an automatically shifting sliding-gear or sliding-dog-clutch transmission with certain fixed gear-trains, or any type of mechanism which will produce automatically an infinite number of ratios between engine speeds and driving-wheel speeds. Various types of drive are considered, as well as typical automatic gearshifts, emphasis being given to the operation of the Tyler transmission clutch and to the Mono-Drive transmission. Other subjects are the reactions of operators to automatic gearshifting and the future of automatic transmission. The desirable features of an automatic transmission are stated as being reliability; quiet operation; reasonable cost, weight, simplicity and efficiency; and correct functioning, which means that it must do the right thing at the right time.
1933-01-01
Technical Paper
330014
O. C. Bridgeman, H. S. White, F. B. Gary
THIS report covers information obtained on vapor lock, fuel-line temperatures and vapor-handling capacity as the result of road tests with 46 cars. The investigation was conducted under the auspices of the Cooperative Fuel Research Steering Committee in cooperation with the Natural Gasoline Association of America. The general procedure consisted in operating the car with samples of gasoline of increasing vapor pressure until vapor lock occurred. The development of a method for the evaluation of the vapor-handling capacity of fuel systems under various operating conditions has been of material assistance in analyzing the vapor-lock problem. The present work indicates that changes both in fuel-line temperatures and in vapor-handling capacity affect the permissible vapor pressures. It is still believed that lowering of fuel-line temperatures by changes in design of the fuel system is the most effective method of insuring freedom from vapor lock.
1933-01-01
Technical Paper
330004
F. M. Thomas, H. W. Fairchild
THIS paper tells how to obtain and evaluate maximum speed of airplanes in level flight. Relationship between available thrust horsepower and powers required to overcome both induced and non-induced resistances is given, in order to provide a clearer understanding of the items affecting maximum speed and the various ways of evaluating changes in that speed. Maintenance of a constant density altitude in combination with a constant engine power or airplane speed is most satisfactory, the authors show. Charts enabling a pilot to attain these conditions in flight are given, together with a method of manifold-pressure calibration of the engine and the use of such calibration in determining the engine power in flight.
1933-01-01
Technical Paper
330060
T. B. Rendel
1933-01-01
Technical Paper
330062
J. B. Fisher
1933-01-01
Technical Paper
330054
ARTHUR NUTT
1933-01-01
Technical Paper
330055
Georges Broulhiet
1933-01-01
Technical Paper
330037
W. R. Jennings
Mr. Jennings describes a test now being considered for determining the point of optimum superheat for lifting iron from a static to a dynamic condition, with tensile strength of alloyed cast iron of 80,000 lb. per sq. in. and of heat-treated iron of 100,000 lb. per sq. in. When this field is entered, increased temperature becomes necessary for consistent results, and a series of tests is being run to discover approximately the temperature at which breakdown of the carbon nucleus occurs. The electric furnace, Mr. Jennings asserts, offers a non-oxidizing and non-contaminating method of melting iron at any desired temperature and allows iron to become high-brow and choosy.
1933-01-01
Technical Paper
330040
M. C. Horine
BY their lack of uniformity and disregard of scientific and economic fact, legislative restrictions on motor-transport vehicles now in force in the states militate against efficient transportation and thus retard economic recovery. In this indirect way and in several direct ways the same situation presents problems to truck builders. Variations in state requirements necessitate undue diversity of designs, present difficult engineering problems, discourage enterprise, threaten the American system of production and penalize good engineering and sound manufacture.
1933-01-01
Technical Paper
330066
Jack Frye
1932-11-01
Magazine
1932-10-01
Magazine
1932-02-01
Magazine
1932-01-01
Technical Paper
320015
L. F. Maurer
1932-01-01
Technical Paper
320033
H. L. Horning
1932-01-01
Technical Paper
320030
Dennistoun Burney
CONVENTIONAL automobile design is no longer suited to conditions of higher driving speeds brought about by road improvement and of smaller but more powerful engines. Study of aerodynamics and analysis of forces and motions induced in a car by location of the center of gravity and distribution of weight led the author, an ex-British naval officer, to conclude that the streamline form and the disposition of the engine behind the rear axle would result in a car giving the greatest comfort in riding and economy of power at high speed and one of pleasing appearance. The reasoning that resulted in these conclusions is set forth, and reference is made to a number of unconventional designs produced in Europe and America, such as front-wheel-drive and rear-engined cars.
1932-01-01
Technical Paper
320029
Donald B. Brooks
THE AUTHOR discusses the permissible interpolation interval for use in routine detonation testing as affected by octane number, engine, and adjustment of the bouncing-pin apparatus. Test results presented show that, with suitable adjustment, the use of a 10-unit interval does not materially reduce precision although it greatly reduces the time and the quantities of materials needed for the test. To determine an economical and practical method of suitably adjusting the bouncing-pin regularly and rapidly for the use of large interpolation intervals will require further research.
1932-01-01
Technical Paper
320051
Gordon Lefebvre
1932-01-01
Technical Paper
320045
Louis Ruthenburg
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
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
Magazine
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
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.
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