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Axial Superchargers

Description: Improvements, however, have been attained which permit a shortening of the structure without any impairment of the efficiency. The axial supercharger has a better efficiency and a simpler design than the radial supercharger. The relatively narrow range in which it operates satisfactorily should not be a very disturbing factor for practical flight problems. The length of this type of supercharger may be reduced considerably if some impairment in the efficiency is permitted.
Date: August 1944
Creator: Betz, A.
Partner: UNT Libraries Government Documents Department
open access

Integral Methods in the Theory of the Boundary Layer

Description: From Summary: "The application of the well-known basic principle of mechanics, the principle of Jourdain, to problems of the theory of the boundary layer leads to an equation from which the equations of Von Karman, Leibenson, and Golubev are derived as special cases. The given equation may be employed in other integral methods. The present paper deals with the method of the variation of the thickness of the boundary layer. A number of new approximate formulas valuable in aerodynamic calculation… more
Date: July 1944
Creator: Loitsianskii, L. G.
Partner: UNT Libraries Government Documents Department
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Analysis of Experimental Investigations of the Planing Process of the Surface of Water

Description: Pressure distribution and spray measurements were carried out on rectangular flat and V-bottom planing surfaces. Lift, resistance, and center of pressure data are analyzed and it is shown how these values may be computed for the pure planing procees of a flat or V-bottom suface of arbitrary beam, load and speed, the method being illustrated with the aid of an example.
Date: March 1944
Creator: Sottorf, W.
Partner: UNT Libraries Government Documents Department
open access

Gas Jets

Description: "A brief summary of the contents of this paper is presented here. In part I the differential equations of the problem of a gas flow in two dimensions is derived and the particular integrals by which the problem on jets is solved are given. Use is made of the same independent variables as Molenbroek used, but it is found to be more suitable to consider other functions. The stream function and velocity potential corresponding to the problem are given in the form of series" (p. 1).
Date: August 1944
Creator: Chaplygin, S.
Partner: UNT Libraries Government Documents Department
open access

The Frictional Force with Respect to the Actual Contact Surface

Description: "Hardy's statement that the frictional force is largely adhesion, and to a lesser extent, deformation energy is proved by a simple experiment. The actual contact surface of sliding contacts and hence the friction per unit of contact surface was determined in several cases. It was found for contacts in normal atmosphere to be about one-third t-one-half as high as the macroscopic tearing strength of the softest contact link, while contacts annealed in vacuum and then tested, disclosed frictional … more
Date: August 1944
Creator: Holm, Ragnar
Partner: UNT Libraries Government Documents Department
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The Wall Interference of a Wind Tunnel of Elliptic Cross Section

Description: "The wall interference is obtained for a wind tunnel of elliptic section for the two cases of closed and open working sections. The approximate and exact methods used gave results in practically good agreement. Corresponding to the result given by Glauert for the case of the closed rectangular section, the interference is found to be a minimum for a ratio of minor to major axis of 1:square root of 2" (p. 1).
Date: November 1944
Creator: Tani, Itiro & Sanuki, Matao
Partner: UNT Libraries Government Documents Department
open access

Profile Measurements During Cavitation

Description: One of the problems of modern cavitation research is the experimental determination of the wing loads on airfoils during cavitation. Such experiments were made on various airfoils with the support of the naval ministry at the Kaiser Wilhelm Institute for Flow Research at Goettingen.
Date: January 1944
Creator: Walchner, O.
Partner: UNT Libraries Government Documents Department
open access

Researches on the Piston Ring

Description: "In internal combustion engines, steam engines, air compressors, and so forth, the piston ring plays an important role. Especially, the recent development of Diesel engines which require a high compression pressure for their working, makes, nowadays, the packing action of the piston ring far more important than ever. Though a number of papers have been published in regard to researches on the problem of the piston ring, none has yet dealt with an exact measurement of pressure exerted on the cyl… more
Date: February 1944
Creator: Ebihara, Keikiti
Partner: UNT Libraries Government Documents Department
open access

The Theory of a Free Jet of a Compressible Gas

Description: "In the present report the theory of free turbulence propagation and the boundary layer theory are developed for a plane-parallel free stream of a compressible fluid. In constructing the theory use was made of the turbulence hypothesis by Taylor (transport of vorticity) which gives best agreement with test results for problems involving heat transfer in free jets" (p. 1).
Date: March 1944
Creator: Abramovich, G. N.
Partner: UNT Libraries Government Documents Department
open access

Determination of the Stresses Produced by the Landing Impact in the Bulkheads of a Seaplane Bottom

Description: "The present report deals with the determination of the impact stresses in the bulkhead floors of a seaplane bottom. The dynamic problem is solved on the assumption of a certain elastic system, the floor being assumed as a weightless elastic beam with concentrated masses at the ends (due to the mass of the float) and with a spring which replaces the elastic action of the keel in the center. The distributed load on the floor is that due to the hydrodynamic force acting over a certain portion of … more
Date: January 1944
Creator: Darevsky, V. M.
Partner: UNT Libraries Government Documents Department
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Investigation of Single Stage Axial Fans

Description: The following investigations are connected with experiments on fans carried out by the author in the Gouttingen Aerodynamic Laboratory within the framework of the preliminary experiments for the new Gouttingen wind-tunnel project. A fan rotor was developed which had very high efficiency at the design point corresponding to moderate pressure and which, in addition, could operate at a proportionally high pressure, rise. To establish the determining operating factors the author carried out extensi… more
Date: April 1944
Creator: Ruden, P.
Partner: UNT Libraries Government Documents Department
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Methods of Stress Calculation in Rotating Disks

Description: "The paper describes methods of computing the stresses in disks of a given profile as well as methods of choosing the disk profiles for a given stress distribution for turhines, turbo blowers, and so forth. A new method of integrating the differential equations of Stodola leads to a simplification of the computation for disks of hyperbolic profile" (p. 1).
Date: September 1944
Creator: Tumarkin, S.
Partner: UNT Libraries Government Documents Department
open access

DVL Angular Velocity Recorder

Description: "In many studies, especially of nonstationary flight motion, it is necessary to determine the angular velocities at which the airplane rotates about its various axes. The three-component recorder is designed to serve this purpose. If the angular velocity for one flight attitude is known, other important quantities can be derived from its time rate of change, such as the angular acceleration by differentiations, or - by integration - the angles of position of the airplane - that is, the angles f… more
Date: August 1944
Creator: Liebe, Wolfgang
Partner: UNT Libraries Government Documents Department
open access

Heat Transfer in a Turbulent Liquid or Gas Stream

Description: "The theory of heat.transfer from a solid body to a liquid stream could he presented previously only with limiting assumptions about the movement of the fluid (potential flow, laminar frictional flow). (See references 1, 2, and 3). For turbulent flow, the most important practical case, the previous theoretical considerations did not go beyond dimensionless formulas and certain conclusions as to the analogy between the friction factor and the unit thermal conductance, (See references 4, 5, 6, an… more
Date: October 1944
Creator: Latzko, H.
Partner: UNT Libraries Government Documents Department
open access

Determination of the Actual Contact Surface of a Brush Contact

Description: "The number of partial contact surfaces of a brush-ring contact is measured by means of a statistical method. The particular brush is fitted with wicks - that is, insulated and cemented cylinders of brush material, terminating in the brush surface. The number of partial contact surfaces can be computed from the length of the rest periods in which such wicks remain without current" (p. 1).
Date: August 1944
Creator: Holm, Ragnar
Partner: UNT Libraries Government Documents Department
open access

The Surface Structure of Ground Metal Crystals

Description: "The changes produced on metallic surfaces as a result of grinding and polishing are not as yet fully understood. Undoubtedly there is some more or less marked change in the crystal structure, at least, in the top layer. Hereby a diffusion of separated crystal particles may be involved, or, on plastic material, the formation of a layer in greatly deformed state, with possible recrystallization in certain conditions" (p. 1).
Date: August 1944
Creator: Boas, W. & Schmid, E.
Partner: UNT Libraries Government Documents Department
open access

Comparative Results of Tests on Several Different Types of Nozzles

Description: "This paper presents the results of tests conducted to determine the effect of the constructional elements of a Laval nozzle on the velocity and pressure distribution and the magnitude of the reaction force of the jet. The effect was studied of the shapes of the entrance section of the nozzle and three types of divergent sections: namely, straight cone, conoidal with cylindrical and piece and diffuser obtained computationally by a graphical method due to Professor F. I. Frankle. The effect of t… more
Date: June 1944
Creator: Kisenko, M. S.
Partner: UNT Libraries Government Documents Department
open access

An Experimental Investigation of the Flow of Air in a Flat Broadening Channel

Description: "The wide use of diffusers, in various fields of technology, has resulted in several experimental projects to study the action and design of diffusers. Most of the projects dealt with steam (steam turbine nozzles). But diffusers have other applications - that is, ventilators, smoke ducts, air coolers, refrigeration, drying, and so forth. At present there is another application for diffusers in wind-tunnel design" (p. 1).
Date: January 1944
Creator: Vedernikoff, A. N.
Partner: UNT Libraries Government Documents Department
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