You limited your search to:

  Partner: UNT Libraries Government Documents Department
 Collection: Technical Report Archive and Image Library
Results 15251 - 15274 of 18,906
  |   |  
The compressive yield strength of extruded shapes of 24st aluminum alloy

The compressive yield strength of extruded shapes of 24st aluminum alloy

Date: January 1, 1941
Creator: Templin, R L; Howell, F M & Hartmann, E C
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Contributions to the Data on Theoretical Metallurgy: [Part] 9. The Entropies of Inorganic Substances. Revision (1940) of Data and Methods of Calculation

Contributions to the Data on Theoretical Metallurgy: [Part] 9. The Entropies of Inorganic Substances. Revision (1940) of Data and Methods of Calculation

Date: 1941
Creator: Kelley, K. K.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Correction of the lifting-line theory for the effect of the chord

Correction of the lifting-line theory for the effect of the chord

Date: January 1, 1941
Creator: Jones, Robert T
Description: It is shown that a simple correction for the chord of a finite wing can be deduced from the three-dimensional potential flow around an elliptic plate. When this flow is compared with the flow around a section of an endless plate, it is found that the edge velocity is reduced by the factor 1/E, where E is the ratio of the semiperimeter to the span. Applying this correction to the circulation brings the theoretical lift into closer agreement with experiments.
Contributing Partner: UNT Libraries Government Documents Department
Damping characteristics of dashpots

Damping characteristics of dashpots

Date: January 1, 1941
Creator: Peterson, John B
Description: An investigation of the damping characteristics of dashpots was carried out combining theory and experiment. Laminar flow was assumed and three equations for the steady velocity of a piston moving in a cylinder filled with liquid were derived. In the first equation, the piston was assumed coaxial in the cylinder and, in the second equation, the piston was assumed eccentric in the cylinder with an element of the piston in contact with the cylinder wall. The third equation is for a piston of circular cross section in an elliptical cylinder. Experiments showed that the piston is normally eccentric in the cylinder. The pistons tested were 1.25 and 2 inches in diameter 0.062 to 1.00 inch long, and the clearances varied from 1.36 to 5.16 x 10 to the 3rd power inch. The difference in pressure on the two sides of the piston varied from about 2 to 55 pounds per square inch. The piston velocities for each assembly were measured with damping liquids of three different viscosities. At high piston velocities, when turbulent flow exists, the observed velocities were much lower than the velocities calculated on the basis of laminar flow. Results for a wide range of Reynolds numbers are ...
Contributing Partner: UNT Libraries Government Documents Department
Design charts for cross-flow tubular intercoolers charge-across-tube type

Design charts for cross-flow tubular intercoolers charge-across-tube type

Date: January 1, 1941
Creator: Valerino, Michael F
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The design of fins for air-cooled cylinders

The design of fins for air-cooled cylinders

Date: January 1, 1941
Creator: Biermann, Arnold E & Ellerbrock, Herman H , Jr
Description: An analysis was made to determine the proportions of fins made of aluminum, copper, magnesium, and steel necessary to dissipate maximum quantities of heat for different fin widths, fin weights, and air-flow conditions. The analysis also concerns the determination of the optimum fin proportions when specified limits are placed on the fin dimensions. The calculation of the heat flow in the fins is based on experimentally verified, theoretical equations. The surface heat-transfer coefficients used with this equation were taken from previously reported experiments. In addition to the presentation of fin-design information, this investigation shows that optimum fin dimensions are inappreciably affected by the differences in air flow that are obtained with different air-flow arrangements or by small changes in the length of the air-flow path.
Contributing Partner: UNT Libraries Government Documents Department
Determination of control-surface characteristics from NACA plain-flap and tab data

Determination of control-surface characteristics from NACA plain-flap and tab data

Date: January 1, 1941
Creator: Ames, Milton B & Sears, Richard I
Description: The data from previous NACA pressure-distribution investigations of plain flaps and tabs have been analyzed and are presented in this paper in a form readily applicable to the problems of control-surface design. The experimentally determined variation of aerodynamic parameters with flap chord and tab chord are given in chart form and comparisons are made with the theory. With the aid of these charts and the theoretical relationships for a thin airfoil, the aerodynamic characteristics for control surfaces of any plan form with plain flaps and tabs may be determined. A discussion of the basic equations of the thin-airfoil theory and the development of a number of additional equations that will be helpful in tail design are presented in the appendixes. The procedure for applying the data is described and a sample problem of tail design is included. The data presented and the method of application set forth in this report should provide a reasonably accurate and satisfactory means of computing the aerodynamic characteristics of control surfaces.
Contributing Partner: UNT Libraries Government Documents Department
Determination of control-surface characteristics from NACA plain-flap and tab data

Determination of control-surface characteristics from NACA plain-flap and tab data

Date: January 1, 1941
Creator: Ames, Milton B & Sears, Richard I
Description: The data from previous NACA pressure-distribution investigations of plain flaps and tabs with sealed gaps have been analyzed and are presented in this paper in a form readily applicable to the problems of control-surface design. The experimentally determined variation of aerodynamic parameters with flap chord and tab chord are given in chart form and comparisons are made with the theory. With the aid of these charts and the theoretical relationships for a thin airfoil, the aerodynamic characteristics for control surfaces of any plan form with plain flaps and tabs with sealed gaps may be determined. A discussion of the basic equations of the thin-airfoil theory and the development of a number of additional equations that will be helpful in tail design are presented in the appendixes. The procedure for applying the data is described and a sample problem of horizontal tail design is included. The data presented and the method of application set forth in this report should provide a reasonably accurate and satisfactory means of computing the aerodynamic characteristics of control surfaces.
Contributing Partner: UNT Libraries Government Documents Department
Effect of aging on mechanical properties of aluminum-alloy rivets

Effect of aging on mechanical properties of aluminum-alloy rivets

Date: January 1, 1941
Creator: Roop, Frederick C
Description: Curves and tabular data present the results of strength tests made during and after 2 1/2 years of aging on rivets and rivet wire of 3/16-inch nominal diameter. The specimens were of aluminum alloy: 24s, 17s, and a17s of the duralumin type and 53s of the magnesium-silicide type.
Contributing Partner: UNT Libraries Government Documents Department
Effect of alternately high and low repeated stresses upon the fatigue strength of 25S-T aluminum alloy

Effect of alternately high and low repeated stresses upon the fatigue strength of 25S-T aluminum alloy

Date: January 1, 1941
Creator: Stickley, G W
Description: Fatigue tests were made on one lot of 3/4 inch diameter rolled-and-drawn 25S-T aluminum-alloy rod normal in composition and tensile properties. The specimens were tested at 3500 cycles per second in a rotating-beam fatigue test machine. Tests were made for three ratios (20:1, 50:1, and 200:1) of the number of cycles applied at low stress to the number applied at high stress. In general, failure occurred when the number of cycles at either the low or the high stress approached the ordinary fatigue curve for the material, regardless of the sequence in which the stresses were applied.
Contributing Partner: UNT Libraries Government Documents Department
Effect of body nose shape on the propulsive efficiency of a propeller

Effect of body nose shape on the propulsive efficiency of a propeller

Date: January 1, 1941
Creator: Stickle, George W; Crigler, John L & Naiman, Irven
Description: Report presents the results of an investigation of the propulsive efficiency of three adjustable propellers of 10-foot diameter operated in front of four body nose shapes, varying from streamline nose that continued through the propeller plane in the form of a large spinner to a conventional open-nose radial-engine cowling. One propeller had airfoil sections close to the hub, the second had conventional round blade shanks, and the third differed from the second only in pitch distribution. The blade-angle settings ranged from 20 degrees to 55 degrees at the 0.75 radius. The effect of the body nose shape on propulsive efficiency may be divided into two parts: (1) the change in the body drag due to the propeller slipstream and (2) the change in propeller load distribution due to the change in velocity caused by the body. For the nose shape tested in the report, the first effect is shown to be very small; therefore, the chief emphasis of the report is confined to the second effect.
Contributing Partner: UNT Libraries Government Documents Department
Flow coefficients of monosleeve valves

Flow coefficients of monosleeve valves

Date: January 1, 1941
Creator: Waldron, C D
Description: The flow coefficients of the intake and the exhaust ports of a sleeve-valve cylinder were measured by attaching the cylinder to a large tank and measuring the changes in pressure and temperature in the tank that were caused by short periods of air flow through the valve ports. The derivation of the equations on which the flow coefficients are based is given. The distribution of total pressure in the arms of the sleeve-valve intake manifold was measured. The arms are found to have as little as 75 percent of the total pressure within the manifold entrance.
Contributing Partner: UNT Libraries Government Documents Department
A graphical method of determining pressure distribution in two-dimensional flow

A graphical method of determining pressure distribution in two-dimensional flow

Date: January 1, 1941
Creator: Jones, Robert T & Cohen, Doris
Description: By a generalization of the Joukowski method, a procedure is developed for effecting localized modifications of airfoil shapes and for determining graphically the resultant changes in the pressure distribution. The application of the procedure to the determination of the pressure distribution over airfoils of original design is demonstrated. Formulas for the lift, the moment, and the aerodynamic center are also given.
Contributing Partner: UNT Libraries Government Documents Department
A high-speed motion-picture study of normal combustion, knock and preignition in a spark-ignition engines

A high-speed motion-picture study of normal combustion, knock and preignition in a spark-ignition engines

Date: January 1, 1941
Creator: Rothrock, A M; Spencer, R C & Miller, Cearcy D
Description: Combustion in a spark-ignition engine was investigated by means of the NACA high-speed motion-picture cameras. This camera is operated at a speed of 40,000 photographs a second and therefore makes possible the study of changes that take place in the intervals as short as 0.000025 second. When the motion pictures are projected at the normal speed of 16 frames a second, any rate of movement shown is slowed down 2500 times. Photographs are presented of normal combustion, of combustion from preignitions, and of knock both with and without preignition. The photographs of combustion show that knock may be preceded by a period of exothermic reaction in the end zone that persists for a time interval of as much as 0.0006 second. The knock takes place in 0.00005 second or less.
Contributing Partner: UNT Libraries Government Documents Department
Intercrystalline Cracking of Boiler Steel and Its Prevention

Intercrystalline Cracking of Boiler Steel and Its Prevention

Date: 1941
Creator: Schroeder, W. C. & Berk, A. A.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Internal-flow systems for aircraft

Internal-flow systems for aircraft

Date: January 1, 1941
Creator: Rogallo, F M
Description: An investigation has been made to determine efficient arrangements for an internal-flow system of an aircraft when such a system operates by itself or in combination with other flow systems. The investigation included a theoretical treatment of the problem and tests in the NACA 5-foot vertical wind tunnel of inlet and outlet openings in a flat plate and in a wing.
Contributing Partner: UNT Libraries Government Documents Department
Lateral control required for satisfactory flying qualities based on flight tests of numerous airplanes

Lateral control required for satisfactory flying qualities based on flight tests of numerous airplanes

Date: January 1, 1941
Creator: Gilruth, R R & Turner, W N
Description: Report presents the results of an analysis made of the aileron control characteristics of numerous airplanes tested in flight by the National Advisory Committee for Aeronautics. By the use of previously developed theory, the observed values of pb/2v for the various wing-aileron arrangements were examined to determine the effective section characteristics of the various aileron types.
Contributing Partner: UNT Libraries Government Documents Department
Magnetic Separation of Ores

Magnetic Separation of Ores

Date: 1941
Creator: Dean, Reginald S. & Davis, Charles Wesley
Description: Report issued by the Bureau of Mines over studies conducted on the removal of magnetic materials from iron ores. As stated in the introduction, "this report discusses briefly operations and trends in magnetic separation, explains magnetic separation, describes and classifies the machines used, and outlines their development" (p. 1). This report includes tables, and illustrations.
Contributing Partner: UNT Libraries Government Documents Department
Metal- and Nonmetal-Mine Accidents in the United States During the Calendar Year 1939 (Excluding Coal Mines)

Metal- and Nonmetal-Mine Accidents in the United States During the Calendar Year 1939 (Excluding Coal Mines)

Date: 1941
Creator: Adams, William W. & Kolhos, Mary E.
Description: Report published by the U.S. Bureau of Mines regarding accidents at mines located in the United States for all operations except coal mines. The report includes statistics about the number and kinds of accidents as well as information about the mining operations (i.e., number of persons employed, average amount of work performed per person, etc.).
Contributing Partner: UNT Libraries Government Documents Department
Metal-Mine Accidents in the United States During the Calendar Year 1938

Metal-Mine Accidents in the United States During the Calendar Year 1938

Date: 1941
Creator: Adams, William W. & Kolhos, Mary E.
Description: Report issued by the U.S. Bureau of Mines covering accidents that happened in metal mines located in the United States including statistics for injuries, fatalities, kinds and causes of accidents, and operational data, such as number of mine workers and shifts worked.
Contributing Partner: UNT Libraries Government Documents Department
Mining Practices and Safety at the Lava Cap Gold Mining Corporation Mines, Nevada City-Grass Valley District, California

Mining Practices and Safety at the Lava Cap Gold Mining Corporation Mines, Nevada City-Grass Valley District, California

Date: 1941
Creator: Ash, S. H.
Description: Report issued by the Bureau of Mines discussing mining safety in the Grass Valley mining district. As stated in the introduction, "the purpose of this paper is not to present an outstanding safety record but to show that gold mining can be pursued with the same degree of safety and improvement as any other industry, if and when the management recognizes that it can and must be done" (p. 1). This report includes tables, maps, illustrations, and photographs.
Contributing Partner: UNT Libraries Government Documents Department
Model tests of a wing-duct system for auxiliary air supply

Model tests of a wing-duct system for auxiliary air supply

Date: January 1, 1941
Creator: Bierman, D. & Corson, B. W., Jr.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Report of the Thirtieth National Conference on Weights and Measures, 1940

Report of the Thirtieth National Conference on Weights and Measures, 1940

Date: 1941
Creator: United States. National Bureau of Standards.
Description: Report of the annual conference on weights and measures, hosted by the U.S. National Bureau of Standards in Washington D.C. It includes conference proceedings, a list of attendees, information about committees and officers, and other reports or commentaries discussed at the meetings.
Contributing Partner: UNT Libraries Government Documents Department
Report of the Thirty-First National Conference on Weights and Measures, 1941

Report of the Thirty-First National Conference on Weights and Measures, 1941

Date: 1941
Creator: United States. National Bureau of Standards.
Description: Report of the annual conference on weights and measures, hosted by the U.S. National Bureau of Standards in Washington D.C. It includes conference proceedings, a list of attendees, information about committees and officers, and other reports or commentaries discussed at the meetings.
Contributing Partner: UNT Libraries Government Documents Department