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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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The Vortex Theory and Its Significance in Aviation

Description: This report will present ideas closely related to the vortex conception and illustrate them in the simplest possible terms. In addition to these general considerations, this report will attempt to show the application of the vortex theory in connection with the wing theory.
Date: July 1930
Creator: Betz, A.
Partner: UNT Libraries Government Documents Department
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Riveting in Metal Airplane Construction Part 1 : Riveting Methods and Equipment in German Metal Airplane Construction

Description: "Although all constructors in Germany use duralumin quite frequently, and prefer cold riveting exclusively for permanent (nondetachable) connections of individual structural components, their methods and equipment are very diversified. The differences are due to a great extent to the diversity of structural types and to the special shapes of the individual subassemblies. The results is that different manufacturers have developed totally different riveting methods, as well as entirely different … more
Date: December 1930
Creator: Pleines, Wilhelm
Partner: UNT Libraries Government Documents Department
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Göttingen Six-Component Scale Measurements on a Junkers A 35 Airplane Model

Description: The suggestion for the measurements collected in this report was prompted by the results of spinning experiments. For the theoretical spinning investigations there was a lack of data on lateral force, yawing, and rolling moment of airplanes.
Date: October 1930
Creator: Blenk, Hermann
Partner: UNT Libraries Government Documents Department
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Mathematical treatise on the recovery from a flat spin

Description: In this mathematical investigation, made in collaboration with Dr. Wilhelm Schmidt, we interpret the temporary change (due to some disturbance) in the quantities which define the position of the airplane while in a flat spin. We further examine the effect of this change, of the means resorted to to produce the disturbance, and thus reveal the expedients available for recovering from a flat spin.
Date: November 1930
Creator: Fuchs, R.
Partner: UNT Libraries Government Documents Department
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Investigation of the Variations in the Velocity of the Air Flow About a Wing Profile

Description: Memorandum presenting an investigation to determine the variations in the velocity of the air when it was obliged to flow about a wing profile. Special interest was paid to the determination of velocity as compared with that of the undisturbed flow and of the velocity drop in successive planes perpendicular to the flow direction at increasing distances from the wing profile.
Date: July 1930
Creator: Repenthin, Walter
Partner: UNT Libraries Government Documents Department
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Combating Airplane Fires

Description: This report provides a summary of the important steps to be taken in combating airplane fires. Some considerations and ways of preventing fires from developing are provided.
Date: January 1930
Creator: Brunat, Henri
Partner: UNT Libraries Government Documents Department
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Coefficients of Flow of Standard Nozzles

Description: We first undertook experiments with air, devoted principally to the investigation of the disturbances due to the differences in the nature of the flow to the nozzle. The difficulty of measuring the air, however, caused us to experiment with water. Due to the possibility of measuring the capacity of the container, this method was much more accurate than measuring with Pitot tobes.
Date: January 1930
Creator: Mueller, H. & Peters, H.
Partner: UNT Libraries Government Documents Department
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Experimental Research on the Friction of Pivots

Description: In horology the friction between solids is of the greatest importance; one limited, however, to the application of the laws of Coulomb which, do not at all correspond with reality. This report presents a review of the subject and some general conclusions. The choice of lubricant is discussed as well as the pressure between frictional surfaces. The gears in a watch are used extensively as examples.
Date: May 1930
Creator: Jaquerod, A.; Defossez, L. & Mügeli, H
Partner: UNT Libraries Government Documents Department
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Load Assumptions for Calculating the Strength of Airplanes

Description: "The following load assumptions shall be taken as the basis of the strength calculations. Certain definite load conditions (e.g. of flight, control, landing and transport) shall be assumed. The loads shall be assumed to be safe loads, constant or only slowly variable, and the inertia forces due to elastic deformation are accordingly disregarded. The external forces, the force of gravity and the inertia forces on the whole airplane shall produce a condition of equilibrium" (p. 1).
Date: September 1930
Partner: UNT Libraries Government Documents Department
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Relation Between the Stability Characteristics and the Controllability of German Airplanes

Description: This survey is intended to give a general approximate idea of the stability and controllability of German airplanes. Both flight characteristics, including the behavior of the airplane under the action of deflected controls and external disturbances, and flight performance, which refers to climbing, speed, take-off, and landing qualities.
Date: February 1930
Creator: Hübner, Walter
Partner: UNT Libraries Government Documents Department
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"Gloster" Metal Construction

Description: This report details the methods of construction employed by the Gloster Company in their fabrication of metal aircraft parts. Ribs, spars, wings, and metal treatments to prevent oxidation are all discussed.
Date: June 1930
Partner: UNT Libraries Government Documents Department
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Contribution to the Study of Normal Burning in Gaseous Carbureted Mixtures: Part 1

Description: In the present study it is proposed to provide an equipment permitting the study of the propagation of the region of reaction in mixtures of air and carbureted gases enclosed within a cylinder. Ignition is produced at the end of compression by an electric spark. With this apparatus it is proposed to determine: 1) the influence of the richness of the explosive mixture on the rate of flame propagation; 2) the influence of the degree of volumetric compression on one of the hydrocarbons; 3) the inf… more
Date: January 1930
Creator: Duchene, M. R.
Partner: UNT Libraries Government Documents Department
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Effects of the End Fixation of Airplane Struts

Description: The main purpose of this report is to give references to literature on the subject of end fixation of airplane struts and also to furnish the constructor with a general survey of the simplest methods for estimating the end-fixation effect.
Date: September 1930
Creator: Teichmann, Alfred
Partner: UNT Libraries Government Documents Department
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Impact Tests on Rubber Compression Springs for Airplane Landing Gears

Description: The present report gives the results of tests which were made for the purpose of solving the problem of whether diagrams obtained from pressure tests could be conclusive for the determination of the safe impact coefficients. It is first established that the rubber rings adhere firmly to the compression surfaces during deformation. Suggestions are thus obtained for a constructive simplification of the rubber rings. The hysteresis phenomenon is ascribed to external and internal friction forces. A… more
Date: July 1930
Creator: Hohenemser, K.
Partner: UNT Libraries Government Documents Department
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Velocity Distribution in the Boundary Layer of a Submerged Plate

Description: This report deals with the measurement of the velocity distribution of the air in the velocity of a plate placed parallel to the air flow. The measurements took place in a small wind tunnel where the diameter of the entrance cone is 30 cm and the length of the free jet between the entrance and exit cones is about 2.5 m. The measurements were made in the free jet where the static pressure was constant, which was essential for the method of measurement used.
Date: October 1930
Creator: Hansen, M.
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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Structural Details of the Giant Dornier Seaplane "Do X."

Description: Memorandum presenting a description of the Dornier seaplane Do X. Details of the general description, materials, details of the main wing and upper wing, details of the hull and of the wing stubs, tail surfaces and control lines, power plant, and launching car and floating dock are provided.
Date: January 1930
Creator: Gustosa, Corrado
Partner: UNT Libraries Government Documents Department
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Balanced and Servo Control Surfaces

Description: "Many reports on various control systems are available, but the results cannot be generally applied since the effect of particular changes of surface-form and mounting are subject to variations depending upon airfoil section and influences of airplane layout. This report presents a simple analysis of several control systems in more general use. Elevators, ailerons, and rudders are all discussed" (p. 1).
Date: May 1930
Partner: UNT Libraries Government Documents Department
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Diesel-Engine Investigations: Ignition-Chamber Engines

Description: This report presents a thorough investigation of the functioning process and injection and combustion characteristics of ignition-chamber engines.
Date: October 1930
Creator: Neumann, Kurt
Partner: UNT Libraries Government Documents Department
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Flight Tests for the Determination of Static Longitudinal Stability

Description: The accuracy of the instruments used for flight test measurements has been inadequate so a new series of tests were commissioned with the development of an accurate elevator setting recorder.
Date: September 1930
Creator: Blenk, Hermann
Partner: UNT Libraries Government Documents Department
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English Airplane Construction

Description: English airplane construction is presented with a particular emphasis on metal construction techniques. Steel rib and fuselage construction are discussed as well as the use of duralumin in construction.
Date: December 1930
Creator: Schwencke, D.
Partner: UNT Libraries Government Documents Department
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A Possible Method for Preventing the Autorotation of Airplane Wings

Description: "At the suggestion of Professor Betz, the following device was tested with the object of reducing the autorotational speed of airplane wings. The model of a normal wing with the Gottigen profile 420, 1 meter span and 0.2 meter chord was provided with a pair of symmetrical slots on the suction side, connected with each other inside the wing. The arrangement of the testing equipment and models are given and the effect of the slots can be seen in the experimental curves that are included" (p. 1).
Date: June 1930
Creator: Schrenk, Oskar
Partner: UNT Libraries Government Documents Department
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