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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.

First experiences with the rotating laboratory

Description: This report describes experiences with a rotating cylinder to explore the effects of motion and flow upon human sensory organs. One observation was that the variation of the resultant line of gravity (from gravity and centrifugal force) was not felt so strongly as might be expected. The impressions produced by the physical effects on the members of the body, especially the ones caused by the deflecting force (Coriolis force), are exactly what the laws of physics would lead us to expect, although somewhat surprising when observed in one's own body.
Date: July 1926
Creator: Prandtl, L.

Fuels for High-Compression Engines

Description: "From theoretical considerations one would expect an increase in power and thermal efficiency to result from increasing the compression ratio of an internal combustion engine. In reality it is upon the expansion ratio that the power and thermal efficiency depend, but since in conventional engines this is equal to the compression ratio, it is generally understood that a change in one ratio is accompanied by an equal change in the other. Tests over a wide range of compression ratios (extending to ratios as high as 14.1) have shown that ordinarily an increase in power and thermal efficiency is obtained as expected provided serious detonation or preignition does not result from the increase in ratio" (p. 483).
Date: 1926
Creator: Sparrow, Stanwood W.

Functioning of Reduction Gears on Airplane Engines

Description: "In undertaking to analyze the functioning conditions of a reduction gear on an aviation engine, we will consider an ordinary twelve-cylinder V-engine. The reduction gear employed consists either of a pair of spur gears, one of which is integral with the engine shaft and the other with the propeller shaft, or of a planetary system of gears" (p. 1).
Date: March 1926
Creator: Matteucci, Raffaelli

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 Gasoline Situation

Description: Report issued by the Bureau of Mines discussing the demands on the oil industry due to an increase in automobiles in the United States. Improvements in drilling methods and refinery practices are presented. This report includes a table.
Date: March 1926
Creator: Hill, Harry H.

General Index to Experiment Station Record, Volumes 26-40, 1912-1919

Description: A topical, alphabetically arranged index to volumes 26-40 including experiment station records, publications reviewed, and foreign publications. In has a 'Consolidated Table of Contents' which lists all editorial notes and publications of the experiment stations and Department of Agriculture from the referenced volumes.
Date: March 1926
Creator: United States. Office of Experiment Stations.

German Training Airplane, Arado "Ar. S.I."

Description: Circular presenting a description of the Arado Ar. S.I., which is a wireless biplane that is both physically attractive and highly performing. A description of the components, controls, construction, characteristics, flying qualities, drawings, and photographs are provided.
Date: May 1926
Creator: Manigold, G.

Improving the Performance of a Compression Ignition Engine by Directing Flow of Inlet Air

Description: "The object of this report is to present the results of tests performed by the National Advisory Committee for Aeronautics to determine the effect on engine performance of directing the flow of the inlet air to a 5-inch by 7-inch cylinder, solid injection, compression ignition engine, After a few preliminary tests, comparative runs were made at a speed of 1500 r.p.m. with and without directed air flow. It was found that directing the flow of the inlet air toward the fuel injection valve gave steadier engine operation, and an appreciable increase in power, and decreased fuel consumption" (p. 1).
Date: July 1926
Creator: Kemper, Carlton

Inertia Factors of Ellipsoids for Use in Airship Design

Description: This report is based on a study made by the writer as a member of the Special Committee on Design of Army Semirigid Airship RS-1 appointed by the National Advisory Committee for Aeronautics. The increasing interest in airships has made the problem of the potential flow of a fluid about an ellipsoid of considerable practical importance. In 1833 George Green, in discussing the effect of the surrounding medium upon the period of a pendulum, derived three elliptic integrals, in terms of which practically all the characteristics of this type of motion can be expressed. The theory of this type of motion is very fully given by Horace Lamb in his "Hydrodynamics," and applications to the theory of airships by many other writers. Tables of the inertia coefficients derived from these integrals are available for the most important special cases. These tables are adequate for most purposes, but occasionally it is desirable to know the values of these integrals in other cases where tabulated values are not available. For this reason it seems worth while to assemble a collection of formulae which would enable them to be computed directly from standard tables of elliptic integrals, circular and hyperbolic functions and logarithms without the need of intermediate transformations. Some of the formulae for special cases (elliptic cylinder, prolate spheroid, oblate spheroid, etc.) have been published before, but the general forms and some special cases have not been found in previous publications. (author).
Date: January 1, 1926
Creator: Tuckerman, L. B.

Influence of the Orifice on Measured Pressures

Description: "The influence of different orifices on the result of measuring the same pressure distributions is the subject of this note. A circular cylinder is exposed to an air stream perpendicular to its axis and its pressure distribution is repeatedly determined. The pressures measured on the downstream half of the cylinder do not change for the orifice sizes used in the tests" (p. 1).
Date: November 1926
Creator: Hemke, Paul E.

An investigation of the characteristics of steel diaphragms for automatic fuel-injection valves

Description: "This research on steel diaphragms was undertaken at the Langley Memorial Aeronautical Laboratory, as a part of a general investigation on fuel injection engines for aircraft. The work determined the load-deflection, load- deformation and hysteresis characteristics for single diaphragms having thicknesses from 0.00s inch to 0.012 inch, and for similar diaphragms tested in multiple having total thicknesses from 0.012 inch to 0.180 inch. The elastic limit loads and deflections, and rupture points of single diaphragms were also determined. Some work was done on diaphragms having central orifices in order to determine the effect of orifice diameter upon the load deflection characteristics" (p. 1).
Date: April 1926
Creator: Joachim, W. F.