UNT Libraries Government Documents Department - 195 Matching Results

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Removing boundary layer by suction

Description: "Through the utilization of the "Magnus effect" on the Flettner rotor ship, the attention of the public has been directed to the underlying physical principle. It has been found that the Prandtl boundary-layer theory furnishes a satisfactory explanation of the observed phenomena. The present article deals with the prevention of this separation or detachment of the flow by drawing the boundary layer into the inside of a body through a slot or slots in its surface" (p. 1).
Date: January 1926
Creator: Ackeret, J.

Experiments with an airfoil from which the boundary layer is removed by suction

Description: Our attempts to improve the properties of airfoils by removing the boundary layer by suction, go back to 1922. The object of the suction is chiefly to prevent the detachment of the boundary layer from the surface of the airfoil. At large angles of attack, such detachment prevents the attainment of the great lift promised by the theory, besides greatly increasing the drag, especially of thick airfoils. This report gives results of those experiments.
Date: August 1926
Creator: Ackeret, J.; Betz, A. & Schrenk, O.

Coal-Mine Fatalities in the United States, 1925

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.
Date: 1926
Creator: Adams, William W.

Coal-Mine Fatalities in May, 1926

Description: Report issued by the U.S. Bureau of Mines on the coal-mining related deaths in May, 1926. The 126 accidents are documented and categorized. The accidents are analyzed in order to prevent future accidents, and to implement safety procedures. This report includes tables.
Date: June 1926
Creator: Adams, William Waugh

A resume of the advances in theoretical aeronautics made by Max M. Munk

Description: In order to apply profitably the mathematical methods of hydrodynamics to aeronautical problems, it is necessary to make simplifications in the physical conditions of the latter. To begin with, it is allowable in many problems, as Prandtl has so successfully shown, to treat the air as having constant density and as free of viscosity. But this is not sufficient. It is also necessary to specify certain shapes for the solid bodies whose motion through the air is discussed, shapes suggested by the actual solids - airships or airfoils - it is true, but so chosen that they lead to solvable problems. In a valuable paper presented by Dr. Max M. Munk, of the National Advisory Committee for Aeronautics, Washington, to the Delft Conference in April, 1924, these necessary simplifying assumptions are discussed in detail. It is the purpose of the present paper to present in as simple a manner as possible some of the interesting results obtained by Dr. Munk's methods.
Date: January 1, 1926
Creator: Ames, Joseph S

Experiments on Autorotation

Description: This article deals principally with Professor Bairstow's experiments on autorotation, in which the wing is free to rotate about an axis in its plane of symmetry, which axis is parallel with the direction of the wind.
Date: September 1926
Creator: Anderlik, E.

Designing Seaplane Hulls and Floats

Description: Experimental data, such as the results of tank tests of models, render it possible to predict, at least in principle, as to how a hull or float of a given shape will comport itself. We will see further along, however, how uncertain these methods are and how they leave room for empiricism, which will reign for a long time yet in seaplane research bureaus.
Date: August 1926
Creator: Benoit

Approximate Calculation of the Static Longitudinal Stability of Airplanes

Description: It seems desirable to have some simple method for calculating quickly and with sufficient accuracy: 1) the correct position of the center of gravity; 2) the requisite tail-group dimensions; 3) and the course of the wing and tail-group moments. In out deductions, we will first replace the biplane (disregarding the effect of stagger, decalage and induced drag) by an equivalent monoplane, whose dimensions and position in space can be approximately determined in a simple manner.
Date: November 1926
Creator: Bienen, Theodor

Spindled and hollow spars

Description: The most usual method of arriving at the maximum amount of spindling or hollowing out permissible in the case of any particular spar section is by trial and error, a process which is apt to become laborious in the absence of good guessing - or luck. The following tables have been got out with the object of making it possible to arrive with certainty at a suitable section at the first attempt.
Date: October 1926
Creator: Blyth, J. D.

The Bowie-Gavin Process: Its Application to the Cracking of Tars and Heavy Oils, Also to the Recovery of Oil from Oil-Soaked Sands or Shales, or from Oil Shales

Description: Technical paper issued by the Bureau of Mines over the Bowie-Gavin process. As stated in the introduction, "this paper describes a process and an apparatus designed to recover oil from such deposits" (p. 1). The results of experiments conducted using this process are discussed. This paper includes tables, illustrations, and photographs.
Date: 1926
Creator: Bowie, C. P.

The Lateral Failure of Spars

Description: It was concluded that after the critical span or depth-breadth ratio has been reached, the modulus of rupture varies approximately inversely as the first power of the span and of the depth-breadth ratio. The direction of the lateral deflection is alternate between successive supports. For this reason, we believe that rib spacing along the spar is more important in reducing lateral deflection than the distance between supports at the strut points.
Date: March 1926
Creator: Bromley, Stevens & Robinson, William H., Jr.

The fundamental principles of high-speed semi-diesel engines. Part 1: a general discussion of the subject of fuel injection in diesel engines and detailed descriptions of many types of injection nozzles

Description: Three questions relating to the technical progress in the utilization of heavy oils are discussed. The first question considers solid injection in high-speed automobile engines, the second concerns the development of the hot-bulb engine, and the third question relates to the need for a more thorough investigation of the processes on which the formatation of combustible, rapidly-burning mixtures depend.
Date: April 1926
Creator: Büchner

The effect of tube length upon the recorded pressures from a pair of static orifices in a wing panel

Description: Report presenting an investigation to determine the effect of tubing length on the indicated pressure values as ascertained in the pressure distribution measurements on the PW-9. The purpose was to determine the percentage of error in the pressure readings which might be caused by various lengths of tubing between the pressure orifices and pressure cell at the manometer. The differences in head caused by variations in the length of tubing are small, the lowest recorded being zero, the highest 2.7 percent.
Date: November 1926
Creator: Carroll, T. & Mixon, R. E.

The Resistance to the Steady Motion of Small Spheres in Fluids

Description: "There seems to be little reliable information conveniently available as to the resistance encountered by small spheres moving steadily at moderate speeds in fluids. The present paper, while presenting nothing new in the way of either theory or data, has three objects: first to show that published data are sufficient to furnish approximate information; second to present this information in form convenient for computation; and, third to indicate where further research is needed" (p. 1).
Date: February 1926
Creator: Castleman, R. A.

N.A.C.A. Flight-Path Angle and Air-Speed Recorder

Description: "A new trailing bomb-type instrument for photographically recording the flight-path angle and air speed of aircraft in unaccelerated flight is described. The instrument consists essentially of an inclinometer, air-speed meter and a film-drum case. The inclinometer carries an oil-damped pendulum which records optically the flight-path angle upon a rotating motor-driven film drum. The air-speed meter consists of a taut metal diaphragm of high natural frequency which is acted upon by the pressure difference of a Prandtl type Pitot-static tube" (p. 1).
Date: April 1926
Creator: Coleman, Donald G.