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Coal-Mine Fatalities in the United States, 1929

Coal-Mine Fatalities in the United States, 1929

Date: 1931
Creator: Adams, William W.
Description: Report compiled by the U.S. Bureau of Mines including statistics on fatalities in coal mines located in the United States as well as data regarding the various operations (e.g., number of miners employed and average production). The information is organized into tables for comparison and the text draws some overall conclusions in the summary.
Contributing Partner: UNT Libraries Government Documents Department
Comparative flight performance with an NACA Roots supercharger and a turbocentrifugal supercharger

Comparative flight performance with an NACA Roots supercharger and a turbocentrifugal supercharger

Date: January 1, 1931
Creator: Schey, Oscar W & Young, Alfred W
Description: This report presents the comparative flight results of a roots supercharger and a turbocentrifugal supercharger. The tests were conducted using a modified DH-4M2 airplane. The rate of climb and the high speed in level flight of the airplane were obtained for each supercharger from sea level to the ceiling. The unsupercharged performance with each supercharger mounted in place was also determined. The results of these tests show that the ceiling and rate of climb obtained were nearly the same for each supercharger, but that the high speed obtained with the turbocentrifugal was better than that obtained with the roots. The high-speed performance at 21,000 feet was 122 and 142 miles per hour for the roots and turbocentrifugal, respectively.
Contributing Partner: UNT Libraries Government Documents Department
Concrete Stoppings in Coal Mines for Resisting Explosions: Detailed Tests of Typical Stoppings and Strength of Coal as a Buttress

Concrete Stoppings in Coal Mines for Resisting Explosions: Detailed Tests of Typical Stoppings and Strength of Coal as a Buttress

Date: 1931
Creator: Rice, George S.; Greenwald, H. P.; Howarth, H. C. & Avins, S.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The design and development of an automatic injection valve with an annular orifice of varying area

The design and development of an automatic injection valve with an annular orifice of varying area

Date: January 1, 1931
Creator: Joachim, William F; Hicks, Chester W & Foster, Hampton H
Description: The purpose of this investigation was to provide an automatic injection valve of simple construction which would produce a finely atomized oil spray of broad cone angle and would fulfill the requirements of fuel injection in aircraft oil engines. The injection valve designed has only six parts - i. e., two concentric nozzle tubes flared at one end, two body parts, and two nuts. Analysis and engine tests indicate that the fuel spray from this type of injection valve has characteristics which reduce the time lag of autoignition and promote efficient combustion in high-speed oil engines.
Contributing Partner: UNT Libraries Government Documents Department
The design of airplane wing ribs

The design of airplane wing ribs

Date: January 1, 1931
Creator: Newlin, J A & Trayer, George W
Description: The purpose of this investigation was to obtain information for use in the design of truss and plywood forms, particularly with reference to wing ribs. Tests were made on many designs of wing ribs, comparing different types in various sizes. Many tests were also made on parallel-chord specimens of truss and plywood forms in place of the actual ribs and on parts of wing ribs, such as truss diagonals and sections of cap strips. It was found that for ribs of any size or proportions, when they were designed to obtain a well-balanced construction and were carefully manufactured, distinct types are of various efficiencies; the efficiency is based on the strength per unit of weight. In all types of ribs the heavier are the stronger per unit of weight. Reductions in the weight of wing ribs are accompanied even in efficient designs by a much greater proportional reduction in strength.
Contributing Partner: UNT Libraries Government Documents Department
The design of plywood webs for airplane wing beams

The design of plywood webs for airplane wing beams

Date: January 1, 1931
Creator: Trayer, George W
Description: This report deals with the design of plywood webs for wooden box beams to obtain maximum strength per unit weight. A method of arriving at the most efficient and economical web thickness, and hence the most suitable unit shear stress, is presented and working stresses in shear for various types of webs and species of plywood are given. The questions of diaphragm spacing and required glue area between the webs and flange are also discussed.
Contributing Partner: UNT Libraries Government Documents Department
The effect of reduction gearing on propeller-body interference as shown by full-scale wind-tunnel tests

The effect of reduction gearing on propeller-body interference as shown by full-scale wind-tunnel tests

Date: January 1, 1931
Creator: Weick, Fred E
Description: This report presents the results of full-scale tests made on a 10-foot 5-inch propeller on a geared J-5 engine and also on a similar 8-foot 11-inch propeller on a direct-drive J-5 engine. Each propeller was tested at two different pitch settings, and with a large and a small fuselage. The investigation was made in such a manner that the propeller-body interference factors were isolated, and it was found that, considering this interference only, the geared propellers had an appreciable advantage in propulsive efficiency, partially due to the larger diameter of the propellers with respect to the bodies, and partially because the geared propellers were located farther ahead of the engines and bodies.
Contributing Partner: UNT Libraries Government Documents Department
The effect of small variations in profile of airfoils

The effect of small variations in profile of airfoils

Date: January 1, 1931
Creator: Ward, Kenneth E
Description: This report deals with the effect of small variations in ordinates specified by different laboratories for the airfoil section. This study was made in connection with a more general investigation of the effect of small irregularities of the airfoil surface on the aerodynamic characteristics of an airfoil. These tests show that small changes in airfoil contours, resulting from variations in the specified ordinates, have a sufficiently large effect upon the airfoil characteristics to justify the taking of great care in the specification of ordinates for the construction of models.
Contributing Partner: UNT Libraries Government Documents Department
Effect of turbulence in wind-tunnel measurements

Effect of turbulence in wind-tunnel measurements

Date: January 1, 1931
Creator: Dryden, H L & Kuethe, A M
Description: This paper gives some quantitative measurements of wind tunnel turbulence and its effect on the air resistance of spheres and airship models, measurements made possible by the hot wire anemometer and associated apparatus in its original form was described in Technical Report no. 320 and some modifications are presented in an appendix to the present paper. One important result of the investigation is a curve by means of which measurements of the air resistance of spheres can be interpreted to give the turbulence quantitatively. Another is the definite proof that the discrepancies in the results on the N. P. L. Standard airship models are due mainly to differences in the turbulences of the wind tunnels in which the tests were made. An attempt is made to interpret the observed results in terms of the boundary layer theory and for this purpose a brief account is given of the physical bases of this theory and of conceptions that have been obtained by analogy with the laws of flow in pipes.
Contributing Partner: UNT Libraries Government Documents Department
Effect of variation of chord and span of ailerons on rolling and yawing moments at several angles of pitch

Effect of variation of chord and span of ailerons on rolling and yawing moments at several angles of pitch

Date: January 1, 1931
Creator: Heald, R H; Strother, D H & Monish, B H
Description: This report presents the results of an extension to higher angles of attack of the investigation of the rolling and yawing moments due to ailerons of various chords and spans on two airfoils having the Clark Y and U. S. A. 27 wings. The measurements were made at various angles of pitch but at zero angle of roll and yaw, the wing chord being set at an angle of +4 degrees to the fuselage axis. In the case of the Clark Y airfoil the measurements have been extended to a pitch angle of 40 degrees, using ailerons of span equal to 67 per cent of the wing semispan and chord equal to 20 and 30 per cent of the wing chord. The work was conducted on wing models of 60-inch span and 10-inch chord.
Contributing Partner: UNT Libraries Government Documents Department