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  Partner: UNT Libraries Government Documents Department
 Decade: 1920-1929
 Collection: National Advisory Committee for Aeronautics Collection
A resume of the advances in theoretical aeronautics made by Max M. Munk

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

Date: January 1, 1926
Creator: Ames, Joseph S
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.
Contributing Partner: UNT Libraries Government Documents Department
Experiments on autorotation

Experiments on autorotation

Date: September 1, 1926
Creator: Anderlik, E
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.
Contributing Partner: UNT Libraries Government Documents Department
The stresses in columns under combined axial and side loads

The stresses in columns under combined axial and side loads

Date: July 1, 1922
Creator: Arnstein, Karl
Description: The problem before us is to determine the total stresses in an axially loaded column of any degree of restraint which is also subject to transverse bending both from a uniformly distributed load and from concentrated loads.
Contributing Partner: UNT Libraries Government Documents Department
Some principles governing the establishment of meteorological stations along air routes

Some principles governing the establishment of meteorological stations along air routes

Date: March 1, 1922
Creator: Aujames, P
Description: The organization of a meteorological service for an air route involves the solution of two distinct problems: distribution and grouping of meteorological stations and communications. Experience gained in the establishment of two lines, Paris-Warsaw and Constantinople-Bucharest enables us to establish certain principles, which may be of interest to note here.
Contributing Partner: UNT Libraries Government Documents Department
:The fundamental principles of high-speed semi-diesel engines. Part II: a discussion of the semi-diesel principle and its application to various types of solid-injection engines

:The fundamental principles of high-speed semi-diesel engines. Part II: a discussion of the semi-diesel principle and its application to various types of solid-injection engines

Date: April 1, 1926
Creator: BUCHNER
Description: Three high-speed semi-diesel engines are examined through the use of indicator diagrams. Different fuel nozzles and fuels are investigated and conclusions are drawn.
Contributing Partner: UNT Libraries Government Documents Department
:The fundamental principles of high-speed semi-diesel engines. Part III: a discussion of fuel mixing and ignition, with special reference to engines with precombustion chambers

:The fundamental principles of high-speed semi-diesel engines. Part III: a discussion of fuel mixing and ignition, with special reference to engines with precombustion chambers

Date: April 1, 1926
Creator: BUCHNER
Description: A continuation of the discussion and overview of the present state of development of high-speed semi-diesel engines.
Contributing Partner: UNT Libraries Government Documents Department
Langley Field wind tunnel apparatus

Langley Field wind tunnel apparatus

Date: October 1, 1921
Creator: Bacon, D L
Description: The difficulties experienced in properly holding thin tipped or tapered airfoils while testing on an N.P.L. type aerodynamic balance even at low air speeds, and the impossibility of holding even solid metal models at the high speeds attainable at the National Advisory Committee's wind tunnel, necessitated the design of a balance which would hold model airfoils of any thickness and at speeds up to 150 m.p.h. In addition to mechanical strength and rigidity, it was highly desirable that the balance readings should require a minimum amount of correction and mathematical manipulation in order to obtain the lift and drag coefficients and the center of pressure. The balance described herein is similar to one in use at the University of Gottingen, the main difference lying in the addition of a device for reading the center of pressure directly, without the necessity of any correction whatsoever. Details of the design and operation of the device are given.
Contributing Partner: UNT Libraries Government Documents Department
Langley Field wind tunnel apparatus

Langley Field wind tunnel apparatus

Date: January 1, 1922
Creator: Bacon, D L
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Preliminary experiments to determine scale and slip-stream effects on a 1/24th size model of a JN4H biplane

Preliminary experiments to determine scale and slip-stream effects on a 1/24th size model of a JN4H biplane

Date: January 1, 1923
Creator: Bacon, D L
Description: This work was undertaken to obtain results on a small model of a complete airplane which might be used for comparison with corresponding tests made in full flight. Somewhat similar tests have been previously made at various other laboratories; but as certain discrepancies exist between corresponding tests in different tunnels, it has been deemed advisable to obtain a direct comparison for this particular installation. The present work covers tests on a one-twenty-fourth scale model at speeds varying from 6.7 m/sec. (15 m.p.h.) to 40.2 m/sec, (90 m.p.h.). A slip stream correction has been obtained by the use of a small belt-driven propeller mounted in front of the model, and force coefficients thus obtained are compared with the measurements of the same forces made in full flight on a geometrically similar airplane. This report gives lift, drag, and longitudinal moment values obtained in tests of a particularly accurate model over a wide range of speeds. A measure of the slip stream corrections on lift and drag forces was obtained by the use of a power-driven model propeller. Measurements were also made of forces and longitudinal moments for all angles from 0 degree to 360 degrees.
Contributing Partner: UNT Libraries Government Documents Department
The resistance of spheres in wind tunnels and in air

The resistance of spheres in wind tunnels and in air

Date: January 1, 1924
Creator: Bacon, D L
Description: To supplement the standardization tests now in progress at several laboratories, a broad investigation of the resistance of spheres in wind tunnels and free air has been carried out by the National Advisory Committee for Aeronautics. The subject has been classed in aerodynamic research, and in consequence there is available a great mass of data from previous investigations. This material was given careful consideration in laying out the research, and explanation of practically all the disagreement between former experiments has resulted. A satisfactory confirmation of Reynolds law has been accomplished, the effect of means of support determined, the range of experiment greatly extended by work in the new variable density wind tunnel, and the effects of turbulence investigated by work in the tunnels and by towing and dropping tests in free air. It is concluded that the erratic nature of most of the previous work is due to support interference and differing turbulence conditions. While the question of support has been investigated thoroughly, a systematic and comprehensive study of the effects of scale and quality of turbulence will be necessary to complete the problem, as this phase was given only general treatment.
Contributing Partner: UNT Libraries Government Documents Department