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Aerodynamic Forces on a Vibrating Unstaggered Cascade
"The unsteady aerodynamic forces, [based on two-dimensional incompressible flow considerations], are determined for an unstaggered cascade, the blades of which are vibrating in phase in an approach flow parallel to the blades" (p. 1).
Date:
August 1957
Creator:
Söhngen, H.
System:
The UNT Digital Library
Study of the Micro-Nonuniformity of the Plastic Deformation of Steel
"The plastic flow during deformation of real polycrystalline metals has specific characteristics which distinguish the plastic deformation of metals from the deformation of ordinary isotropic bodies. One of these characteristics is the marked micro-nonuniformity of the plastic deformation of metals. P.O. Pashkov demonstrated the presence of a considerable micro-nonuniformity of the plastic deformation of coarse-grained steel wit medium or low carbon content" (p. 1).
Date:
August 1957
Creator:
Chechulin, B. B.
System:
The UNT Digital Library
Effects of Intermittent Versus Continuous Heating upon the Tensile Properties of 2024-T4, 6061-T6 and 7075-T6 Alloys
In some applications, aluminum alloys are subjected to intermittent heating at elevated temperature. It is generally considered that the effects of such intermittent heating are cumulative, and therefore are the same as if the heating had been continuous for the same total length of time. The object of these tests was to determine the effects of intermittent and continuous heating at 300 and 400 F, for total periods of 100 and 200 hr, upon the tensile properties of 2024-T4 and 6061-T6 alloy rolled-and-drawn rod and 7075-T6 alloy extrusions, at room temperature and at the temperature of heating.
Date:
August 1956
Creator:
Stickley, G. W. & Anerson, H. L.
System:
The UNT Digital Library
The Fatigue Strength of Riveted Joints and Lugs
This report deals with a number of tests on riveted joints and lugs for the primary purpose of comparing the several types of riveted joints and to study the effect of various factors on the fatigue strength of lugs. A check was made to ascertain whether or not an estimate of the fatigue life at a certain loading could be made from the dimensions of the joint and the fatigue data of the unnotched materials. Recommendations are made on the proportioning of joints to obtain better fatigue behavior.
Date:
August 1956
Creator:
Schijve, J.
System:
The UNT Digital Library
Safeguards Against Flutter of Airplanes
This report is a compilation of practical rules, derived at the same time from theory and from experience, intended to guide the aeronautical engineer in the design of flutter-free airplanes. Rules applicable to the wing, the ailerons, flaps, tabs,tail surfaces, and fuselage are discussed.
Date:
August 1956
Creator:
De Vries, Gerhard
System:
The UNT Digital Library
Tests to Determine the Adhesive Power of Passenger-Car Tires
"The concept of the adhesive power of a tire with respect to the road involves several properties which result from the purpose of the tire; namely, connecting link between vehicle and road: (1) The tire must transfer the tractive and braking forces acting in the direction of travel (tractive and braking adhesion); (2) The tire is to prevent lateral deviations of the vehicle from the desired direction of travel (track adhesion)" (p. 1).
Date:
August 1956
Creator:
Förster, B.
System:
The UNT Digital Library
Papers on Shimmy and Rolling Behavior of Landing Gears Presented at Stuttgart Conference October 16 and 17, 1941
Report presenting a compilation of papers on shimmy and rolling behavior of landing gears.
Date:
August 1954
Creator:
Fromm, H.; Hoffman, E.; Harling, R.; Schrode, H.; Kraft, P.; Scheubel, Franz Nikolaus et al.
System:
The UNT Digital Library
On the Representation of the Stability Region in Oscillation Problems With the Aid of the Hurwitz Determinants
This report concerns the use of the Hurwitz determinants in defining boundaries of regions where oscillatory phenomena are to be stable or unstable. A simplification is suggested as an aid in reducing the computations usually required, although it is emphasized that point checks in the various regions defined are required using the complete set of Hurwitz determinants or some other complete stability determination.
Date:
August 1952
Creator:
Sponder, E.
System:
The UNT Digital Library
The Flow of Gases in Narrow Channels
Measurements were made of the flow of gases through various narrow channels a few microns wide at average pressures from 0.00003 to 40 cm. Hg. The flow rate, defined as the product of pressure and volume rate of flow at unit pressure difference, first decreased linearly with decrease in mean pressure in the channel, in agreement with laminar-flow theory, reached a minimum when the mean path length was approximately equal to the channel width, and then increased to a constant value. The product of flow rate and square root of molecular number was approximately the same function of mean path length for all gases for a given channel.
Date:
August 1951
Creator:
Rasmussen, R. E. H.
System:
The UNT Digital Library
Lateral Control by Spoilers at the DVL
"The present report describes the development of spoiler control at the DVL from the end of 1936 until the beginning of 1939. The authors are fully aware that the present report also forms only a contribution to the problem of spoiler control and offers at best a possibility of extrapolation regarding the behavior of the control in modern airplanes. A modern airplane (Me 109) is being reconstructed for conversion to spoiler control" (p. 1).
Date:
August 1951
Creator:
Kramer, Max; Zobel, Theodor W. & Esche, C. G.
System:
The UNT Digital Library
On the recording of turbulent longitudinal and transverse fluctuations
"A thorough understanding of the turbulent flow movements cannot be arrived at from investigations of the temporal mean values of the flows alone. Study of the fluctuation phenomena themselves is indispensable. Thus turbulence research entered a new promising stage when investigators started performing fluctuation measurements and basing theories on those measurements" (p. 1).
Date:
August 1951
Creator:
Reichardt, H.
System:
The UNT Digital Library
Three Papers From Conference On "Wing and Tail-Surface Oscillations: March 6-8, 1941, Munich
Memorandum presenting three papers regarding aerodynamic balance of control surfaces. The specific topics covered include some general remarks regarding aerodynamically balanced control surfaces, aerodynamically equivalent systems for various forms of control surfaces within the scope of two-dimensional wing theory, and comparative calculations concerning aerodynamic balance of control surfaces.
Date:
August 1951
Creator:
Söhngen, Heinz; Schwarz, L. & Dietze, F.
System:
The UNT Digital Library
Contribution to the Problem of Buckling of Orthotropic Plates, With Special Reference to Plywood
Planar stress-strain relations and bending stress-strain relations are presented for elastic orthotropic plates and specialized to plywood. These relations are used to derive the differential equation and energy expression for the buckling of orthotropic rectangular plates whose principal stiffness directions are not parallel to the plate edges. Buckling analyses are made for the case of pure compression and pure shear of a long plate-strip.
Date:
August 1950
Creator:
Thielemann, Wilhelm
System:
The UNT Digital Library
Dependence of the Elastic Strain Coefficient of Copper on the Pre-Treatment
The effect of various pre-treatments on the elastic strain coefficient (alpha) (defined as the reciprocal of the modulus of elasticity E) (Epsilon) and on the mechanical hysteresis of copper has been investigated. Variables comprising the pre-treatments were pre-straining by stretching in a tensile testing machine and by drawing through a die, aging at room and elevated temperatures and annealing. The variation of the elastic strain coefficient with test stress was also investigated.
Date:
August 1950
Creator:
Kuntze, Wilhelm
System:
The UNT Digital Library
Investigations of Lateral Stability of a Glide Bomb Using Automatic Control Having No Time Lag
The investigation of the lateral stability of an automatically controlled glide bomb led also to the attempt of clarifying the influence of a phugoid oscillation or of any general longitudinal oscillation on the lateral stability of a glide bomb. Under the assumption that its period of oscillation considerably exceeds the rolling and yawing oscillation and that c(sub a) is, at least in sections, practically constant, the result of this test is quite simple. It becomes clear that the influence of the phugoid oscillation may be replaced by suitable variation of the rolling-yawing moment on a rectilinear flight path instead of the phugoid oscillation.
Date:
August 1950
Creator:
Sponder, E. W.
System:
The UNT Digital Library
Flow Measurement by Means of Light Interference
"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 density field in the neighborhood of a test body by optical means" (p. 1).
Date:
August 1949
Creator:
Zobel
System:
The UNT Digital Library
Moments of Cambered Round Bodies
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
System:
The UNT Digital Library
Measurements on Compressor-Blade Lattices
From Summary: "At the end of 1940 an investigation of a guide-vane lattice for the compressor of a TL unit [NACA comment: Turbojet] was requested. The greatest possible Mach number had to be attained. The investigation was conducted with an annular lattice subjected to axial flow. A direct-current shunt motor with a useful output of 235 horsepower at an engine speed of 1800 qm was available for driving the necessary blower."
Date:
August 1948
Creator:
Weinig, F.
System:
The UNT Digital Library
Rotating Disks in the Region of Permanent Deformation
This technical memorandum is a mathematical investigation of the problem of overspeeded disks. New methods must be sought for obtaining a satisfactory stress equalization in the cross section of these disks.
Date:
August 1948
Creator:
László, F.
System:
The UNT Digital Library
Concerning the Velocity of Evaporation of Small Droplets in a Gas Atmosphere
"The evaporation velocity of liquid droplets under various conditions is theoretically calculated and a number of factors are investigated which are neglected in carrying out the fundamental equation of Maxwell. It is shown that the effect of these factors at the small drop sizes and the small weight concentrations ordinarily occurring in fog can be calculated by simple corrections. The evaporation process can be regarded as quasi-stationary in most cases" (p. 1).
Date:
August 1947
Creator:
Fuchs, N.
System:
The UNT Digital Library
Cones in Supersonic Flow
"In the case of cones in axially symmetric flow of supersonic velocity, adiabatic compression takes place between shock wave and surface of the cone. Interpolation curves betwen shock polars and the surface are therefore necessary for the complete understanding of this type of flow. They are given in the present report by graphical-numerical integration of the differential equation for all cone angles and airspeeds" (p. 1).
Date:
August 1947
Creator:
Hantzsche, W. & Wendt, H.
System:
The UNT Digital Library
Equations for Adiabatic but Rotational Steady Gas Flows Without Friction
This paper makes the following assumptions: 1) The flowing gases are assumed to have uniform energy distribution. ("Isoenergetic gas flows," that is valid with the same constants for the the energy equation entire flow.) This is correct, for example, for gas flows issuing from a region of constant pressure, density, temperature, end velocity. This property is not destroyed by compression shocks because of the universal validity of the energy law.
Date:
August 1947
Creator:
Schäefer, Manfred
System:
The UNT Digital Library
Investigations on Reductions of Friction on Wings, in Particular by Means of Boundary Layer Suction
Memorandum presenting investigation on reductions of friction on wings, especially by means of boundary-layer suction. The report is broken up into several sections, including: causes of transition, laminar profiles with the transition taking place, laminar boundary-layer suction, investigation of the laminar pressure increase, investigation of the slot flow for laminar boundary-layer suction with single slots, tests about keeping a boundary layer for high Reynolds laminar with the aid of boundary-layer suction, and an investigation of a slightly-cambered laminar suction profile of 10.5-percent thickness.
Date:
August 1947
Creator:
Pfenninger, Werner
System:
The UNT Digital Library
Lift and Drag of Wings with Small Span
The lift coefficient of a wing of small span at first shows a linear increase for the increasing angle of attack, but to a lesser degree then was to be expected according to the theory of the lifting line; thereafter the lift coefficient increases more rapidly than linearity, as contrasted with the the theory of the lifting line. The induced drag coefficient for a given lift coefficient, on the other hand, is obviously much smaller than it would be according to the theory. A mall change in the theory of the lifting line will cover these deviations.
Date:
August 1947
Creator:
Weinig, F.
System:
The UNT Digital Library