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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.
Partner: UNT Libraries Government Documents Department
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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" (p. 1).
Date: August 1926
Creator: Ackeret, J.; Betz, A. & Schrenk, O.
Partner: UNT Libraries Government Documents Department
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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.
Partner: UNT Libraries Government Documents Department
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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
Partner: UNT Libraries Government Documents Department
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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
Partner: UNT Libraries Government Documents Department
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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" (p. 1).
Date: October 1926
Creator: Blyth, J. D.
Partner: UNT Libraries Government Documents Department
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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
Partner: UNT Libraries Government Documents Department
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Tail Planes

Description: This report presents methods by which the cells of large commercial airplanes may be reduced. The tail of large airplanes represent an area where considerable improvement in weight and size reduction can be attained.
Date: August 1926
Creator: Constantin, L.
Partner: UNT Libraries Government Documents Department
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Recent Developments in the Construction and Operation of All-Metal Airplanes

Description: Experiments on the effect of atmosphere and of sea water on the building materials employed by us have been carried on for years in the North Sea with the aid of the Hamburg Naval Observatory. Parallel experiments are being made at the Pisa Naval Observatory in the Mediterranean Sea. Metal sheets, sections, assemblies and experimental floats are being exposed to the action of the elements. Different construction techniques are discussed and a variety of specific airplanes are presented which in… more
Date: September 1926
Creator: Dornier, C.
Partner: UNT Libraries Government Documents Department
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Experiments With Rotating Cylinders in Combination With Airfoils

Description: Memorandum presenting an investigation of whether rotating cylinders can be advantageously used in combination with airfoils in airplane construction.
Date: October 1926
Creator: Frey, Kurt
Partner: UNT Libraries Government Documents Department
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Metal Spars

Description: Certain principles are common to all metal spars and the design of a particular metal spar is followed throughout the design process.
Date: June 1926
Creator: Haddon, J. D.
Partner: UNT Libraries Government Documents Department
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Experimental Investigation of the Physical Properties of Medium and Heavy Oils, Their Vaporization and Use in Explosion Engines Part 1

Description: While little has been accomplished in obtaining an abundant supply of light oils from coal and heavy oils, progress has been made on engine design to make use of the heavier oils. Progress has been made in two different directions which are outlined in this paper: the group of engines with medium and high-pressure carburetion in the cylinder; and the group of engines with low-pressure carburetion of the heavy oils before reaching the cylinder.
Date: May 1926
Creator: Heinlein, Fritz
Partner: UNT Libraries Government Documents Department
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Experimental Investigation of the Physical Properties of Medium and Heavy Oils, Their Vaporization and Use in Explosion Engines Part 3

Description: The test equipment for studying the vaporization of heavy and medium oils is described as well as some of the experimental properties explored such as vaporization speed and diffusion coefficient. The experimental arrangement is also discussed.
Date: October 1926
Creator: Heinlein, Fritz
Partner: UNT Libraries Government Documents Department
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Experimental Investigation of the Physical Properties of Medium and Heavy Oils, Their Vaporization and Use in Explosion Engines Part 4

Description: This report presents a theoretical treatment of the vaporization process of medium and heavy oils. The results of this investigation, which were mostly obtained from the lighter components of the heavy fuels, require a 10- or 16-fold vaporization in comparison with gasoline. We must attain a still finer degree of atomization, in order to include the heavier components.
Date: December 1926
Creator: Heinlein, Fritz
Partner: UNT Libraries Government Documents Department
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Two-Stroke-Cycle Engines for Airplanes

Description: Now that the two-stroke-cycle engine has begun to make its appearance in automobiles, it is important to know what services we have a right to expect of it in aeronautics, what conditions must be met by engines of this type for use on airplanes and what has been accomplished.
Date: January 1926
Creator: Jalbert, J.
Partner: UNT Libraries Government Documents Department
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Flight Tests on Airplanes

Description: This report presents test procedures, methods, and instruments for flight testing of aircraft. Dynamic-pressure gauges are discussed at length.
Date: April 1926
Creator: Koppe, Heinrich
Partner: UNT Libraries Government Documents Department
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Development of Light and Small Airplanes

Description: Memorandum presenting an overview of the development of light and small airplanes. Some of the characteristics explored include the development of airplanes of medium weight, development in countries other than Germany, development of light airplanes, general constructive fiducial lines, safety problems, the economy problem, and some special structural considerations are provided.
Date: July 1926
Creator: Lachmann, G.
Partner: UNT Libraries Government Documents Department
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Central Aerohydrodynamic Institute of Moscow, Russia

Description: The staff and construction of the Institute are described as well as a variety of experiments and researches being conducted there. The six sections of the laboratory are described, including the Section for Theoretical Researches, Section for Aerodynamic Researches, Windmill Section, Section for Engine-Propeller Groups, Section for Material Testing, and Section for Instrument Making. Special attention is given to the various wind tunnels and testing facilities present.
Date: November 1926
Creator: Margoulis, W.
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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Devices for Prevention of Stalled Flight

Description: Memorandum describing warning or correcting devices based on the registering of two distinct factors, the air speed and the angle of attack. The authors of the report define the conditions for the flight of an airplane and then study the causes of stalled flight in the different cases where it can occur.
Date: November 1926
Creator: Mazer, Paul
Partner: UNT Libraries Government Documents Department
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