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The Boundary Layer as a Means of Controlling the Flow of Liquids and Gases

Description: According to one of the main propositions of the boundary layer theory the scarcely noticeable boundary layer may, under certain conditions, have a decisive influence on the form of the external flow by causing it to separate from the wing surface. These phenomena are known to be caused by a kind of stagnation of the boundary layer at the point of separation. The present report deals with similar phenomena. It is important to note that usually the cause (external interference) directly affects … more
Date: March 1930
Creator: Schrenk, Oskar
Partner: UNT Libraries Government Documents Department
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Static Longitudinal Stability Of "Ente" Airplanes

Description: The stability conditions of Ente (duck) airplanes are investigated in this report. In developing the formulas, which afford an approximate solution, the unimportant effect of the height of the C.G. and the moment of the residual resistance are neglected. The effect of downwash from the forward horizontal empennage on the wing are also disregarded.
Date: March 1931
Creator: Kiel, Heinrich Georg
Partner: UNT Libraries Government Documents Department
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Problems Concerning the Stability and Maneuverability of Airplanes

Description: "The stability of an airplane can be easily determined by wind-tunnel tests, especially by simple tests with models mounted wind-vane fashion. However, each stability curve plotted by this method is valid only for a certain setting of the corresponding control surface, i.e., it characterizes the stability of the airplane with the control stick in a given position. The problems thus defined are studied from the point of view of longitudinal and transverse stability. Directional stability is not … more
Date: March 1932
Creator: Biche, Jean
Partner: UNT Libraries Government Documents Department
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Accurate Calculation of Multispar Cantilever and Semicantilever Wings With Parallel Webs Under Direct and Indirect Loading

Description: In the present report the computation is actually carried through for the case of parallel spars of equal resistance in bending without direct loading, including plotting of the influence lines; for other cases the method of calculation is explained. The development of large size airplanes can be speeded up by accurate methods of calculation such as this.
Date: March 1932
Creator: Sänger, Eugen
Partner: UNT Libraries Government Documents Department
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A Few More Mechanical-Flight Formulas Without the Aid of Polar Diagrams

Description: The reliability of the assumption of a parabolic shape of the polar curve is investigated and found satisfactory for all practical purposes. It is further shown that the aerodynamically best possible or "ideal" airplane is produced on this assumption. Lastly, detailed suggestions are given on the possibilities of application of this method of calculation. It especially simplifies the design and evaluation of structural changes and the determination of the limits of technical possibilities. The … more
Date: March 1928
Creator: Schrenk, Martin
Partner: UNT Libraries Government Documents Department
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Elmira Soaring Contest, 1930

Description: This report details the Elmira, New York soaring contest of 1930 and provides up-current maps, experiences in piloting, distance flights, and a few details on glider design.
Date: March 1931
Creator: Hirth, Wolfram K. E.; Schempp, Martin H. & Herrick, Jack
Partner: UNT Libraries Government Documents Department
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NACA Conference on High-Speed Aerodynamics: A Compilation of Papers Presented

Description: A reproduction of the technical papers presented by staff members of the NACA Laboratories at the NACA Conference on High-Speed Aerodynamics at the Ames Aeronautical Laboratory during March 18-20, 1958. The primary purpose of the conference was to convey to military services and contractors the results of recent research and to provide an opportunity to discuss the results.
Date: 1958-03-18/1958-03-20
Partner: UNT Libraries Government Documents Department
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NACA Conference on Aircraft Loads, Structures, and Flutter

Description: "This document contains reproductions of technical papers on some of the most recent research results on aircraft loads, flutter, and structures from the NACA laboratories. These papers were presented by members of the staff of the NACA laboratories at the Conference held at the Langley Aeronautical Laboratory March 5, 6, and 7, 1957. The primary purpose of this Conference was to convey to contractors of the military services and others concerned with the design of aircraft these recent researc… more
Date: March 5, 1957
Partner: UNT Libraries Government Documents Department
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Spontaneous Combustion of Hydrogen

Description: It is shown by the author's experiments that hydrogen which escapes to the atmosphere through openings in the system may burn spontaneously if it contains dust. Purely thermal reasoning can not account for the combustion. It seems to be rather an electrical ignition. In order to determine whether the cause of the spontaneous ignition was thermo-chemical, thermo-mechanical, or thermo-electrical, the experiments in this paper were performed.
Date: March 4, 1922
Creator: Pothmann, P. & Nusselt, Wilhelm
Partner: UNT Libraries Government Documents Department
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The vector ruling protractor

Description: The theory, structure and working of a vector slide rule is presented in this report. This instrument is used for determining a vector in magnitude and position when given its components and its moment about a point in their plane.
Date: March 1924
Creator: Zahm, A. F.
Partner: UNT Libraries Government Documents Department
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The Practical Difficulties of Commercial Flying

Description: This paper relates some of the problems commercial aircraft companies have in attracting larger numbers of paying customers. The author discusses some remedies such as changing the public perception of flying as dangerous.
Date: March 1924
Creator: Courtney, F. T.
Partner: UNT Libraries Government Documents Department
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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
Partner: UNT Libraries Government Documents Department
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Analytical methods for computing the polar curves of airplanes

Description: This report presents a method of calculating polar curves which is at least as precise as graphical methods, but it more rapid. Knowing the wind tunnel test of a wing and the performances of an airplane of the same profile, it is easy to verify the characteristic coefficients and, at the same time, the methods determining induced resistances.
Date: March 1921
Creator: Le Sueur
Partner: UNT Libraries Government Documents Department
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Analysis of flight and wind-tunnel tests on Udet airplanes with reference to spinning characteristics

Description: This report presents an analysis of results of wind-tunnel tests conducted at the D.V.L. Values were determined for the effectiveness of all the controls at various angles of attack. The autorotation was studied by subjecting the rotating model to an air blast.
Date: March 1929
Creator: Herrmann, H.
Partner: UNT Libraries Government Documents Department
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German Aircraft Accident Statistics, 1930

Description: The investigation of all serious accidents, involving technical defects in the airplane or engine, is undertaken by the D.V.L. in conjunction with the imperial traffic minister and other interested parties. All accidents not clearly explained in the reports are subsequently cleared up.
Date: March 1932
Creator: Weitzmann, Ludwig
Partner: UNT Libraries Government Documents Department
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Optico-Photographic Measurements of Airplane Deformations

Description: "The deformation of aircraft wings is measured by photographically recording a series of bright shots on a moving paper band sensitive to light. Alternating deformations, especially vibrations, can thus be measured in operation, unaffected by inertia. A handy recording camera, the optograph, was developed by the static division of the D.V.L. (German Experimental Institute for Aeronautics) for the employment of this method of measurement on airplanes in flight" (p. 1).
Date: March 1931
Creator: Küssner, Hans Georg
Partner: UNT Libraries Government Documents Department
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The Electrodynamometric Balance of the Small Wind Tunnel of the French Service of Aeronautical Research

Description: This investigation shows the attempt to improve the electrodynamomoter designed by Mr. Villey. The force to be measured acts on a flexible steel plate which is placed in front of a fixed plate. The deformation varies the original thickness of the layer of air between the two plates, thus causing a more rapid variation in the coefficient of electrostatic attraction of the two plates than in the capacity of the condenser formed by the dynamometer.
Date: March 1930
Creator: Rebuffet, P.
Partner: UNT Libraries Government Documents Department
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Mechanical Control of Airplanes

Description: "Before undertaking a detailed description of an automatic-control mechanism, I will state briefly the fundamental conditions for such devices. These are: 1) it must be sensitive at one or more reference values; 2) it must stop the angular motions of the airplane not produced by the pilot; and 3) it must be possible to switch it off and on by a simple hand lever" (p. 1).
Date: March 1929
Creator: Boykow, H.
Partner: UNT Libraries Government Documents Department
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Evolution of the Helicopter

Description: Report presenting an investigation of problems related to helicopters. Also included are the history of the evolution of the helicopter and a series of propeller experiments.
Date: March 1923
Creator: Balaban, Karl
Partner: UNT Libraries Government Documents Department
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