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Moments of Cambered Round Bodies

Description: Results are presented for the moments and position of force centers of a series of cambered round bodies derived from a torpedo-like body of revolution. The effects of placing fins on the rear of the body of revolution are also included.
Date: August 1949
Creator: Kempf, Günther
Partner: UNT Libraries Government Documents Department
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The theory of plasticity in the case of simple loading accompanied by strain-hardening

Description: The author has previously shown that a deformation theory of plasticity is entirely adequate when the loading is simple; that is, when all the applied forces grow in proportion to a single parameter. The author now shows how a general plasticitytheory for any complex loading may be constructed by successively adding quantities of the nature of correction terms to the deformation theory. All of the theories of plasticity so far suggested for the complex loading condition are shown to be special … more
Date: February 1949
Creator: Ilyushin, A. A.
Partner: UNT Libraries Government Documents Department
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Lecture Series "Boundary Layer Theory". Part I - Laminar Flows, Part 1, Laminar Flows

Description: Report presenting a lecture series that aims to give a survey of the more recent results of the theory of viscous fluids and their importance to actual applications. The primary focus is on the theory of the boundary of frictional layer.
Date: April 1949
Creator: Schlichting, H.
Partner: UNT Libraries Government Documents Department
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On the Motions of an Oscillating System Under the Influence of Flip-Flop Controls

Description: "So-called flip-flop controls (also called "on-off-course controls") are frequently preferred to continuous controls because of their simple construction. Thus they are used also for the steering control of airplanes. Such a body possesses-even if one thinks, for instance, only of the symmetric longitudinal motion - three degrees of freedom so that a study of its motions under the influence of an intermittent control is at least lengthy. Thus, it is suggested that an investigation of the basic … more
Date: November 1949
Creator: Flügge-Lotz, I. & Klotter, K.
Partner: UNT Libraries Government Documents Department
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Two-Dimensional Wing Theory in the Supersonic Range

Description: The plane problem of the vibrating airfoil in supersonic flow is dealt with and solved within the scope of a linearized theory by the method of the acceleration potential.
Date: June 1949
Creator: Hönl, H.
Partner: UNT Libraries Government Documents Department
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Two-Dimensional Motion of a Gas at Large Supersonic Velocities

Description: "A large number of papers have been devoted to the problem of integration of equations of two-dimensional steady nonvertical adiabatic motion of a gas. Most of these papers are based on the application of the hodograph method of S. A. Chaplygin in which the plane of the hodograph of the velocity is taken as the region of variation of the independent variables in the equations of motion; the equations become linear in this plane. The exact integration of these equations is, however, obtained in … more
Date: October 1949
Creator: Falkovich, S. V.
Partner: UNT Libraries Government Documents Department
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Systematic model researches on the stability limits of the DVL series of float designs

Description: "To determine the trim range in which a seaplane can take off without porpoising, stability tests were made of a Plexiglas model, composed of float, wing, and tailplane, which corresponded to a full-size research airplane. The model and full-size stability limits are in good agreement. After all structural parts pertaining to the air frame were removed gradually, the aerodynamic forces replaced by weight forces, and the moment of inertia and position of the center of gravity changed, no marked … more
Date: December 1949
Creator: Sottorf, W.
Partner: UNT Libraries Government Documents Department
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Experimental Flights for Testing of a Reactor as an Expedient for the Termination of Dangerous Spins

Description: "In the Institute for Flight Mechanics of the DVL a reactor arrangement with a maximum output of 100 kg was investigated as an expedient for the termination of dangerous spins on an airplane of the FW 56 type. reproduce the influence of a disturbance of the steady spin condition by a pitching or yawing moment. The tests were meant to reproduce the influence of a disturbance of the steady spin condition by a pitching and yawing moment" (p. 1).
Date: July 1949
Creator: Höhler, P. & v. Köppen, I.
Partner: UNT Libraries Government Documents Department
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Computation of Thin-Walled Prismatic Shells

Description: "We consider a prismatic shell consisting of a finite number of narrow rectangular plates and having in the cross-section a finite number of closed contours (fig. 1(a)). We shall assume that the rectangular plates composing the shell are rigidly joined so that there is no motion of any kind of one plate relative to the others meeting at a given connecting line. The position of a point on the middle prismatic surface is considered to be defined by the coordinate z, the distance to a certain init… more
Date: June 1949
Creator: Vlasov, V. Z.
Partner: UNT Libraries Government Documents Department
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Some New Problems on Shells and Thin Structures

Description: "Cylindrical shells of arbitrary section, reinforced by longitudinal and transverse members (stringers and ribs) are considered by us, for a sufficiently close spacing of the ribs, as in our previously published papers (references 1 end 2), as thin-walled orthotropic spatial systems at the cross-sections of which only axial (normal and shearing) forces can arise. The longitudinal bending and twisting moments, due to their weak effect on the stress state of the shell, are taken equal to zero. Al… more
Date: March 1949
Creator: Vlasov, V. S.
Partner: UNT Libraries Government Documents Department
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Behavior of the Laminar Boundary Layer for Periodically Oscillating Pressure Variation

Description: "The calculation of the phenomena within the boundary layer of bodies immersed in a flow underwent a decisive development on the basis of L. Prandtl's trains of thought, stated more than forth years ago, and by numerous later treatises again and again touching upon them. The requirements of the steadily improving aerodynamics of airplanes have greatly increased with the passing of time and recently research became particularly interested in such phenomena in the boundary layer as are caused by … more
Date: September 1949
Creator: Quick, August Wilhelm & Schröder, K.
Partner: UNT Libraries Government Documents Department
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Heat Transmission in the Boundary Layer

Description: "In the present paper which deals with the heat transfer between the gas and the wall for large temperature drops and large velocities use is made of the method of Dorodnitsyn of the introduction of a new independent variable, with this difference, however, that the relation between the temperature field (that is, density) and the velocity field in the general case considered is not assumed given but is determined from the solution of the problem. The effect of the compressibility arising from … more
Date: April 1949
Creator: Kalikhman, L. E.
Partner: UNT Libraries Government Documents Department
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Theory of Characteristics

Description: The theory of characteristics will be presented generally for quasilinear differential equations of the second order in two variables. This is necessary because of the manifold requirements to be demanded from the theory of characteristics.
Date: September 1949
Creator: Tollmien, W.
Partner: UNT Libraries Government Documents Department
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Two-Dimensional Potential Flows

Description: Contents include the following: Characteristic differential equations - initial and boundary conditions. Integration of the second characteristic differential equations. Direct application of Meyer's characteristic hodograph table for construction of two-dimensional potential flows. Prandtl-Busemann method. Development of the pressure variation for small deflection angles. Numerical table: relation between deflection, pressure, velocity, mach number and mach angle for isentropic changes of stat… more
Date: November 1949
Creator: Schäefer, Manfred & Tollmien, W.
Partner: UNT Libraries Government Documents Department
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Lift Force of an Arrow-Shaped Wing

Description: "The flow about a conical body of an ideal compressible fluid is considered. Assume that the velocity of the oncoming flow at infinity W is directed along the z-axis. The system of Cartesian coordinates x, y, z with origin at the vertex of the cone O is shown" (p. 1).
Date: October 1949
Creator: Gurevich, M. I.
Partner: UNT Libraries Government Documents Department
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Contribution to the Problem of Flow at High Speed

Description: Report divided into two sections about flow problems encountered at high speeds. The topics include: 1) A Few General Remarks Covering the Prandtl-Busemann Method; and 2) Effect of Compressibility in Axially Symmetrical Flow around an Ellipsoid.
Date: June 1949
Creator: Schmieden, C. & Kawalki, K. H.
Partner: UNT Libraries Government Documents Department
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Landing Procedure in Model Ditching Tests of Bf 109

Description: The purpose of the model tests is to clarify the motions in the alighting on water of a land plane. After discussion of the model laws, the test method and test procedure are described. The deceleration-time-diagrams of the landing of a model of the Bf 109 show a high deceleration peek of greater than 20g which can be lowered to 4 to 6g by radiator cowling and brake skid.
Date: December 1949
Creator: Sottorf, W.
Partner: UNT Libraries Government Documents Department
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Susceptibility to Welding Cracking, Welding Sensitivity, Susceptibility to Welding Seam Cracking, and Test Methods for These Failures

Description: "In the years after the First World war a very rapid development, which even today has by no means come to an end, took place in the field of welding; here also, as in most technical innovations, failures made their appearance. Thereupon comprehensive Investigations were undertaken by steel manufacturers and consumers with cooperation of the authorities. In most cases the reasons for failure could be determined and eliminated and further occurrences avoided by the use of new test methods" (p. 1… more
Date: June 1949
Creator: Zeyen, K. L.
Partner: UNT Libraries Government Documents Department
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Flow Measurement by Means of Light Interference

Description: "There has been under development for the high-speed wind tunnel of the LFA an optical measuring arrangement for the qualitative and quantitative investigation of flow. By the use of interference measurements, the determination of density at the surface of the bodies being tested in the air stream and in the vicinity of these bodies can be undertaken. The results obtained so far in the simple preliminary investigations show that it is possible, even at a low Reynolds number, to obtain the densi… more
Date: August 1949
Creator: Zobel
Partner: UNT Libraries Government Documents Department
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Systematic Investigations of the Effects of Plan Form and Gap between the Fixed Surface and Control Surface on Simple Flapped Wings

Description: "Four component measurements of 12 wings of symmetric profile having flaps with chord ratios t(sub R)/t(sub L) = 0.3 and t(sub R)/t(sub L) = 0.2 are treated in this report. As a result of the investigations, the effects of plan form and gap between fixed surface and control surface have been clarified. Lift, drag, pitching moment, and hinge moment were measured in the control-surface deflection range: -23 deg < or = beta < or = 23 deg and the range of angle of attack: -20 deg < or = alpha < or … more
Date: May 1949
Creator: Göthert & Röber
Partner: UNT Libraries Government Documents Department
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Experimental study of flow past turbine blades

Description: From Introduction: "The requirements on gas turbines for aircraft power units, namely, adequate efficiency, operation at high gas temperatures, low weight, and small dimensions, must be taken into consideration during the design of the blading. To secure good efficiency, it is necessary that the gas flow past the blades as smoothly as possible without separation. This is relatively easily obtainable in the accelerated flow of turbine blading, if the blade spacing is chosen small enough. A small… more
Date: June 1949
Creator: Eckert, E. & Vietinghoff-Scheel, K. V.
Partner: UNT Libraries Government Documents Department
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On Wind Tunnel Tests and Computations Concerning the Problem of Shrouded Propellers

Description: "Results of measurements on a shrouded propeller are given. The propeller is designed for the high ratio of advance and high thrust loading. The effect of the shape of propeller and shroud upon the aerodynamic coefficients of the propulsion unit can be seen from the results" (p. 1).
Date: February 1949
Creator: Krüger, W.
Partner: UNT Libraries Government Documents Department
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Lame's Wave Functions of the Ellipsoid of Revolution

Description: "Lamé's wave functions result by separation of the wave equation in elliptic coordinates and by integration of the ordinary differential equations thus originating. They are a generalization of Lamé's potential functions which originate in the same manner from the potential equation. Lamé's wave functions are applied for boundary value problems of the wave equation for regions of space bounded by surfaces of a system of confocal ellipsoids and hyperboloids" (p. 1).
Date: April 1949
Creator: Meixner, J.
Partner: UNT Libraries Government Documents Department
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Calculation of Counterrotating Propellers

Description: "A method for calculation of a counterrotating propeller which is similar to Walchner's method for calculation of the single propeller in the free air stream is developed and compared with measurements. Several dimensions which are important for the design are given end simple formulas for the gain in efficiency derived. Finally a survey of the behavior of the propeller for various operating conditions is presented" (p. 1).
Date: March 1949
Creator: Ginzel, F.
Partner: UNT Libraries Government Documents Department
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