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Recent experiments at the Gottingen Aerodynamic Institute
This report presents the results of various experiments carried out at the Gottingen Aerodynamic Institute. These include: experiments with Joukowski wing profiles; experiments on an airplane model with a built-in motor and functioning propeller; and the rotating cylinder (Magnus Effect).
Date:
July 1925
Creator:
Ackeret, J.
System:
The UNT Digital Library
The Stresses in Columns Under Combined Axial and Side Loads
The problem before us is to determine the total stresses in an axially loaded column of any degree of restraint which is also subject to transverse bending both from a uniformly distributed load and from concentrated loads. The solution of this problem is of special importance in the design of aircraft which consist of slender columns" (p. 1).
Date:
July 1922
Creator:
Arnstein, Karl & Truscott, Starr
System:
The UNT Digital Library
Velocity and Pressure Distribution Behind Bodies in an Air Current
The following experiments on the air flow behind bodies were made for the purpose of assisting in the explanation of the phenomena connected with air resistance. The first two series of experiments dealt with the phenomena behind a cylinder. The third series of experiments was carried out behind a streamlined strut.
Date:
July 1924
Creator:
Betz, A.
System:
The UNT Digital Library
The Vortex Theory and Its Significance in Aviation
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.
System:
The UNT Digital Library
Design of Centrifugal Impeller Blades
This paper restricts itself to radial impellers with cylindrical blades since, as Prasil has shown, the flow about an arbitrarily curved surface of revolution may be reduced to this normal form we have chosen by a relatively simple conformal transformation. This method starts from the simple hypotheses of the older centrifugal impeller theory by first assuming an impeller with an infinite number of blades. How the flow is then modified is then investigated.
Date:
July 1939
Creator:
Betz, A. & Flügge-Lotz, I.
System:
The UNT Digital Library
Diagrams for Calculation of Airfoil Lattices
"The field for curved blades is represented by a vortex series with a vortex removed at the blade point. Further, an example of calculation of a curved blade from this series is given, whereby the necessary accuracy required of the different methods in practice is shown according to the case considered" (p. 1).
Date:
July 1942
Creator:
Betz, Albert
System:
The UNT Digital Library
Calculation of the Pressure Distribution on Bodies of Revolution in the Subsonic Flow of a Gas Part 1 - Axially Symmetrical Flow
"The present report concerns a method of computing the velocity and pressure distributions on bodies of revolution in axially symmetrical flow in the subsonic range. The differential equation for the velocity potential Phi of a compressible fluid motion is linearized tn the conventional manner, and then put in the form Delta(Phi) = 0 by affine transformation. The quantity Phi represents the velocity potential of a fictitious incompressible flow, for which a constant superposition of sources by sections is secured by a method patterned after von Karman which must comply with the boundary condition delta(phi)/delta(n) = 0 at the originally specified contour" (p. 1).
Date:
July 1947
Creator:
Bilharz, Herbert & Hölder, Ernst
System:
The UNT Digital Library
Charts for Checking the Stability of Compression Members in Trusses
"The present report contains a set of charts developed for computing the fixity effect on a compression member in a truss through its adjacent members, the amount of fixity being considered variable with the particular total truss load. The use of the charts is illustrated on two- and three-bay systems, as well as on a triangular truss" (p. 1).
Date:
July 1936
Creator:
Borkmann, K.
System:
The UNT Digital Library
Reflection and Refraction of Acoustic Waves by a Shock Wave
"The presence of sound waves in one or the other of the fluid regions on either side of a shock wave is made apparent, in the region under superpressure, by acoustic waves (reflected or refracted according to whether the incident waves lie in the region of superpressure or of subpressure) and by thermal waves. The characteristics of these waves are calculated for a plane, progressive, and uniform incident wave. In the case of refraction, the refracted acoustic wave can, according to the incidence, be plane, progressive, and uniform or take the form of an 'accompanying wave' which remains attached to the front of the shock while sliding parallel to it" (p. 1).
Date:
July 1957
Creator:
Brillouin, J.
System:
The UNT Digital Library
Aero Dopes and Varnishes
Report discussing before proceeding to discuss the preparation of dope solutions, it will be necessary to consider some of the essential properties which should be possessed of a dope film, deposited in and on the surface of an aero fabric. The first is that it should tighten the material and second it should withstand weathering.
Date:
July 1927
Creator:
Britton, H. T. S.
System:
The UNT Digital Library
Aerodynamics and Ballistics
Ballistics is a science hundreds of years old and this report is an attempt to show how these older principles can be used in the newer science of aerodynamics.
Date:
July 1922
Creator:
Burzio, Filippo
System:
The UNT Digital Library
On the Installation of Jet Engine Nacelles on a Wing Fourth Partial Report: Pressure-Distribution Measurements on a Sweptback Wing with Jet Engine Nacelle
"The present report, which deals with pressure-distribution measurements made on a sweptback wing with a jet engine nacelle, is similar to a report on pressure-distribution measurements on a rectangular wing with a jet engine nacelle (second partial report). Here, in investigations preliminary to high-speed measurements, as in the second partial report, useful arrangements and fillet designs have been discovered" (p. 1).
Date:
July 1949
Creator:
Buschner, R.
System:
The UNT Digital Library
Subsonic Gas Flow Past A Wing Profile
"The use of the linearized equations of Chaplygin to calculate the subsonic flow of a gas permits solving the problem of the flow about a wing profile for absence and presence of circulation. The solution is obtained in a practical convenient form that permits finding all the required magnitudes for the gas flow (lift, lift moment velocity distribution over the profile, and critical Mach number). This solution is not expressed in simple closed form; for a certain simplifying assumption, however, the equations of Chaplygin can be reduced to equations with constant coefficients, and solutions are obtained by using only the mathematical apparatus of the theory of functions of a complex variable" (p. 1).
Date:
July 1950
Creator:
Christianovich, S. A. & Yuriev, I. M.
System:
The UNT Digital Library
The Present Status of Airship Construction, Especially of Airship-Framing Construction
"This work proposes to sketch, in broad outline, the status of airship construction in the various countries, at a time when commerce over great distances might be finally opened up to the airship through the performances of the "Graf Zeppelin." After a short historical review, a survey of the most important rigid and semirigid airships built since 1925, their differences and special problems, is made. In more detailed treatment, the framing construction of the more recent rigid airships and some especially interesting structural questions are investigated" (p. 1).
Date:
July 1938
Creator:
Ebner, Hans
System:
The UNT Digital Library
Prediction of Downwash and Dynamic Pressure at the Tail From Free-Flight Measurements
"The present measurements form a continuation of earlier flight tests published in a previous report for predicting the downwash at the tail of an airplane. The method makes use of the tail itself as integrating contact surface to the extent that, beginning from the measurement of the self-alignment of the elevator, the mean downwash angle and dynamic pressure at the tail are determined. The instrumental accuracy is considerably improved if the elevator is completely separate from the controls during the tests, because the effect of friction on the self-alignment of the elevator is then reduced to a minimum and a finer elevator weight balance is rendered possible" (p. 1).
Date:
July 1942
Creator:
Eujen, E.
System:
The UNT Digital Library
The Transport of Vorticity Through Fluids in Turbulent Motion: In the Light of the Prandtl and Taylor Theories
The report studies the problem of the transport of vorticity or of momentum in light of the Taylor and Prandtl theories which are briefly reviewed. It also show how the formulas of Prandtl could be brought into agreement with experimental results in those cases where they agree with the principle of statistic similitude of Karman, and particularly in the problem of the distribution of velocity and temperature in the wake of a heated cylindrical obstacle.
Date:
July 1936
Creator:
Ferrari, C.
System:
The UNT Digital Library
Experimental Results With Airfoils Tested in the High-Speed Tunnel at Guidonia
The results are presented of a triple series of tests using force measurements, pressure-distribution measurements, and air flow photographs on airfoil sections suitably selected so that comparison could be made between the experimental and theoretical results. The comparison with existing theory is followed by a discussion of the divergences found, and an attempt is made to find their explanation.
Date:
July 1940
Creator:
Ferri, Antonio
System:
The UNT Digital Library
Investigations and Experiments in the Guidonia Wind Tunnel
This paper is a presentation of the experiments and equipment used in investigations at the Guidonia wind tunnel. The equipment consisted of: a number of subsonic and supersonic cones, an aerodynamic balance, and optical instruments operating on the Schlieren and interferometer principle.
Date:
July 1939
Creator:
Ferri, Antonio
System:
The UNT Digital Library
Relation Of "Lilienthal Effect" to Dynamic Soaring Flight
"In this article, the phenomena of the upward component in the case of flat surfaces will be referred to as the "Lilienthal effect." The Lilienthal effect will be distinguished from the Knoller-Betz effect which is explained by means of vertical wind oscillations, at the basis of which, however, there lie air motions which the Lilienthal effect could not produce. It will be shown that the same cause, which can produce the Lilienthal effect on flat airfoils, considerably strengthens the thrust due to the Knoller-Betz effect" (p. 1).
Date:
July 1925
Creator:
Fick, Roderich
System:
The UNT Digital Library
Investigation of Flow in a Centrifugal Pump
"The investigation of the flow in a centrifugal pump indicated that the flow patterns in frictional fluid are fundamentally different from those in frictionless fluid. In particular, the dead air space adhering to the section side undoubtedly causes a reduction of the theoretically possible delivery head. The velocity distribution over a parallel circle is also subjected to a noticeable change as a result of the incomplete filling of the passages" (p. 1).
Date:
July 1946
Creator:
Fischer, Karl
System:
The UNT Digital Library
The Design of Jet Pumps
This report shows that by applying both energy and impulse theorems the optimum throat dimension of the mixing nozzle and the best shape of intake can be predicted approximately in a relatively simple manner. The necessary length of the mixing nozzle follows from Prandtl's turbulent mixing theory. The calculations are carried out for the mixing of similar and dissimilar fluids.
Date:
July 1941
Creator:
Flügel, Gustav
System:
The UNT Digital Library
Statistical Study of Turbulence: Spectral Functions and Correlation Coefficients
"In reading the publications on turbulence of different authors, one often runs the risk of confusing the various correlation coefficients and turbulence spectra. We have made a point of defining, by appropriate concepts, the differences which exist between these functions. Besides, we introduce in the symbols a few new characteristics of turbulence" (p. 1).
Date:
July 1958
Creator:
Frenkiel, Francois N.
System:
The UNT Digital Library
Air forces and air-force moments at large angles of attack and how they are affected by the shape of the wing
From Summary: "The present report is, in the first place, a compilation of the test results now available from wing tests up to angles of attack 90^o. Reports are also given of tests with monoplane and auxiliary wings in the Gottingen wind tunnel for the purpose of plotting a steadily rising curve of the normal force as a foundation of the angle of attack."
Date:
July 1930
Creator:
Fuchs, Richard & Schmidt, Wilhelm
System:
The UNT Digital Library
The Dangerous Flat Spin and the Factors Affecting It
This report deals first with the fundamental data required for the investigation. These are chiefly the aerodynamic forces and moments acting on an airplane in a flat spin. It is shown that these forces and moments depend principally on the angle of attack and on the rotation about the path axis, and can therefore either be measured in a wind tunnel or calculated from wind-tunnel measurements of lift, drag and moment about the leading edge of the wing of an airplane model at rest.
Date:
July 1931
Creator:
Fuchs, Richard & Schmidt, Wilhelm
System:
The UNT Digital Library