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Aerodynamic principles of the direct lifting propeller

Description: From Summary: "The purpose of this report is to make the complicated processes on the direct-lift propeller amenable to analysis and observation. This is accomplished by placing the physical phenomena, starting with the most elementary process, in the foreground, while limiting the mathematical treatment to the most essential in view of the fundamental defects of the theorems. Comparison with model experiments supplements and corroborates the theoretical results."
Date: January 1934
Creator: Schrenk, Martin
Partner: UNT Libraries Government Documents Department
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The Buckling of Curved Tension-Field Girders

Description: "The present paper reports on experiments made to determine the buckling load under shear of circular curved tension-field webs. The buckling load of the webs may be expressed with reference to the buckling load of the stiffeners. It is found that within the explored range the buckling load is approximately twice as great as that of the identically stiffened flat wall of equal web depth" (p. 1).
Date: January 1938
Creator: Limpert, G.
Partner: UNT Libraries Government Documents Department
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Calculation of the Induced Efficiency of Heavily Loaded Propellers Having Infinite Number of Blades

Description: Report presenting an approximate method of computing the induced efficiency of heavily loaded propellers in suitable form for extension to finite number of blades and a comparison of results obtained using the method with the data of the Betz-Helmbold theory for heavily loaded propellers.
Date: January 1939
Creator: Lösch, F.; Kramer, K. N.; Bock, G. & Nikodemus, R.
Partner: UNT Libraries Government Documents Department
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Clerget 100 Hp Heavy-Oil Engine

Description: A complete technical description of the Clerget heavy-oil engine is presented along with the general characteristics. The general characteristics are: 9 cylinders, bore 120 mm, stroke 130 mm, four-stroke cycle engine, rated power limited to 100 hp at 1800 rpm; weight 228 kg; propeller with direct drive and air cooling. Moving parts, engine block, and lubrication are all presented.
Date: January 1931
Creator: Léglise, Pierre
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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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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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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The D.V.L. Gliding-Angle Control (W. Hübner Design)

Description: This report describes a device for arbitrary enlargement of the gliding angle of airplanes, especially of such with flat gliding angle and difficult landing characteristics. The D.V.L. gliding angle control (design, Hubner) permits a local interruption of the lift distribution along the span and consequently an increased induced drag. The mechanism comprises two wing rudders operated by lever from the pilot's cockpit. Said rudders are fitted on the top side of the wing near the leading edge. Th… more
Date: January 1933
Creator: Hübner, Walter & Pleines, Wilhelm
Partner: UNT Libraries Government Documents Department
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Dynamic Breaking Tests of Airplane Parts

Description: "The static stresses of airplane parts, the magnitude of which can be determined with the aid of static load assumptions, are mostly superposed by dynamic stresses, the magnitude of which has been but little explored. The object of the present investigation is to show how the strength of airplane parts can best be tested with respect to dynamic stresses with and without superposed static loading, and to what extent the dynamic strength of the parts depends on their structural design. Experiment… more
Date: January 1933
Creator: Hertel, Heinrich
Partner: UNT Libraries Government Documents Department
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Dynamic Testing of Airplane Shock-Absorbing Struts

Description: "Measurement of perpendicular impacts of a landing gear with different shock-absorbing struts against the drum testing stand. Tests were made with pneumatic shock absorbers having various degrees of damping, liquid shock absorbers, steel-spring shock absorbers and rigid struts. Falling tests and rolling tests. Maximum impact and gradual reduction of the impacts in number and time in the falling tests. Maximum impact and number of weaker impacts in rolling tests" (p. 1).
Date: January 1932
Creator: Langer, P. & Thomé, W.
Partner: UNT Libraries Government Documents Department
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Effect of aerodynamic design on glider performance

Description: The performance of a glider is determined by means of the velocity polar, which represents the connection between horizontal and sinking speed. The mean sinking speed for a given speed range can be determined on the basis of the velocity polar. These data form the basis for the most propitious design of a performance-type glider with a view to long-distance flight.
Date: January 1935
Creator: Lippisch, A.
Partner: UNT Libraries Government Documents Department
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Evaluation of Scavenging in Two-Stroke-Cycle Engines

Description: The viewpoints are discussed, according to which the scavenging of two-stroke-cycle engines can be evaluated, and the relations between scavenging pressure and the quantity of the scavenging medium required, as also between the scavenging pressure and the revolution speed, are developed. It is further shown that the power increase is limited by the scavenging process, so that further researches are desirable for qualitative improvement. These results lead to several conclusions regarding the pr… more
Date: January 1934
Creator: Venediger, Herbert J.
Partner: UNT Libraries Government Documents Department
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Flow in Smooth Straight Pipes at Velocities Above and Below Sound Velocity

Description: "To investigate the laws of flow of compressible fluids in pipes, tests were carried out with air flowing at velocities below and above that of sound in straight smooth pipes. Air was chosen as the flow medium. In order that the effect of compressibility may be brought out most effectively, the velocity should lie between 100 and 500 m/s (200 and 1,000 mph); that is, be of the order of magnitude of the velocity of sound in air. The behavior of the compression shock in a smooth cylindrical pipe … more
Date: January 1938
Creator: Frössel, W.
Partner: UNT Libraries Government Documents Department
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Gliding in Convection Currents

Description: "A survey of the possibilities of gliding in convection currents reveals that heretofore only the most simple kind of ascending convection currents, that is, the "thermic" of insolation, has been utilized to any extent. With the increasing experience in gliding, the utilization of the peculiar nature of the "wind thermic" and increased glider speed promises further advances. Evening, ocean, and height "thermic" are still in the exploration stage, and therefore not amenable to survey in their ef… more
Date: January 1935
Creator: Georgii, W.
Partner: UNT Libraries Government Documents Department
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The Gyroplane: Its Principles and Its Possibilities

Description: This report begins by indicating several simple principles concerning the velocity distribution over the blades of a lifting propeller of diameter D, revolving at n revolutions per second, and animated by a horizontal movement of translation at speed V. The calculation, compared with the test data, has shown that the aerodynamic action of the air on the blades depends almost only on the velocity components in a plane at right angles to the blade span. A history of gyroplane and gyrocopter devel… more
Date: January 1937
Creator: Breguet, Louis
Partner: UNT Libraries Government Documents Department
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The Heat Transfer of Cooling Fins on Moving Air

Description: The present report is a comparison of the experimentally defined temperature and heat output of cooling fins in the air stream with theory. The agreement is close on the basis of a mean coefficient of heat transfer with respect to the total surface. A relationship is established between the mean coefficient of heat transfer, the dimensions of the fin arrangement, and the air velocity.
Date: January 1935
Creator: Doetsch, Hans
Partner: UNT Libraries Government Documents Department
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Meteorological-Physical Limitations of Icing in the Atmosphere

Description: The icing hazard can, in most cases, be avoided by correct execution of the flights according to meteorological viewpoints and by meteorologically correct navigation (horizontal and, above all, vertical). The zones of icing hazard are usually narrowly confined. Their location can be ascertained with, in most cases, sufficient accuracy before take-off.
Date: January 1939
Creator: Findeisen, W.
Partner: UNT Libraries Government Documents Department
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The Problem of the Propeller in Yaw With Special Reference to Airplane Stability

Description: The quantity of air which the disk area described by propeller blades travels through, is accelerated rearward conformably to the momentum of the forces acting on the propeller. The accelerated air mass forms behind the propeller the so-called slipstream, in which among others, the mean velocity of advance is increased. If the propeller axis slopes toward the relative flight direction, the slipstream direction likewise changes, i.e., it sets up a downwash behind the propeller.
Date: January 1933
Creator: Misztal, Franz
Partner: UNT Libraries Government Documents Department
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Resistance of Plates and Pipes at High Reynolds Numbers

Description: It was learned that the law of resistance for high R values does not follow the simple powers, and that the powers, which can be obtained approximately for the velocity distribution, gradually change. Since, moreover, very important investigations have recently been made on the resistance of plates at very high R values, it seemed of interest to apply the above line of reasoning to the new general law of resistance. For this purpose, the resistance and velocity distribution along the plate must… more
Date: January 1931
Creator: Schiller, L. & Hermann, R.
Partner: UNT Libraries Government Documents Department
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The Small Wind Tunnel of the DVL

Description: A general description of the small DVL wind tunnel is provided, with emphasis on air conduction, blower and velocity regulation, velocity measurement, and balance and model suspension.
Date: January 1934
Creator: Seewald, Friedrich
Partner: UNT Libraries Government Documents Department
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Status of Wing Flutter

Description: "This report presents a survey of previous theoretical and experimental investigations on wing flutter covering thirteen cases of flutter observed on airplanes. The direct cause of flutter is, in the majority of cases, attributable to (mass-) unbalanced ailerons. Under the conservative assumption that the flutter with the phase angle most favorable for excitation occurs only in two degrees of freedom, the lowest critical speed can be estimated from the data obtained on the oscillation bench" (p… more
Date: January 1936
Creator: Küssner, H. G.
Partner: UNT Libraries Government Documents Department
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