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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 density field in the neighborhood of a test body by optical means" (p. 1).
Date: August 1949
Creator: Zobel
Partner: UNT Libraries Government Documents Department

Lift and Drag of Wings with Small Span

Description: 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.
Partner: UNT Libraries Government Documents Department

Calculations and Experimental Investigations on the Feed-Power Requirement of Airplanes With Boundary-Layer Control

Description: "Calculations and test results are given about the feed-power requirement of airplanes with boundary-layer control. Curves and formulas for the rough estimate of pressure-loss and feed-power requirement are set up for the investigated arrangements which differ structurally and aerodynamically. According to these results the feed power for three different designs is calculated at the end of the report" (p. 1).
Date: September 1947
Creator: Krüger, W.
Partner: UNT Libraries Government Documents Department

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

Pressure-Distribution Measurements on Unyawed Swept-Back Wings

Description: "This report presents comprehensive pressure-distribution measurements on four (4) swept-back wings (phi = 0 deg, 15 deg, 30 deg, and 45 deg) of constant chord and over a large range of angles of attack with symmetrical air flow. The distributions, experimentally obtained, were compared with theoretical ones calculated by the methods of Weissinger and Multhopp" (p. 1).
Date: July 1947
Creator: Jacobs, W.
Partner: UNT Libraries Government Documents Department

Temperatures and Stresses on Hollow Blades For Gas Turbines

Description: "The present treatise reports on theoretical investigations and test-stand measurements which were carried out in the BMW Flugmotoren GMbH in developing the hollow blade for exhaust gas turbines. As an introduction the temperature variation and the stress on a turbine blade for a gas temperature of 900 degrees and circumferential velocities of 600 meters per second are discussed. The assumptions on the heat transfer coefficients at the blade profile are supported by tests on an electrically heated blade model" (p. 1).
Date: September 1947
Creator: Pollmann, Erich
Partner: UNT Libraries Government Documents Department

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).
Date: June 1949
Creator: Zeyen, K. L.
Partner: UNT Libraries Government Documents Department

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 = 20 deg" (p. 1).
Date: May 1949
Creator: Göthert & Röber
Partner: UNT Libraries Government Documents Department

The Influence of the Application of Power during Spin Recovery of Multiengine Airplanes

Description: "The effect of application of power, so far not clarified, is investigated in the present report in order to give the pilot, in addition to the control measures, an expedient for spin recovery of multiengine airplanes. To this end, a series of spins was performed with an airplane of the Go 150 type. It was possible to set up a uniform rule regarding the effect of power, for right end left spins as well as for any combination of the direction of rotation of the propellers" (p. 1).
Date: June 1949
Creator: Höhler, P.
Partner: UNT Libraries Government Documents Department

Investigations of Lateral Stability of a Glide Bomb Using Automatic Control Having No Time Lag

Description: 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.
Partner: UNT Libraries Government Documents Department

Investigations on the Stability, Oscillation, and Stress Conditions of Airplanes with Tab Control: First Partial Report. Derivation of the Equations of Motion and their General Solutions

Description: "For the design and the construction of airplanes the control is of special significance, not only with regard to the flight mechanical properties but also for the proportional arrangement of wing unit, fuselage, and tail unit. Whereas these problems may be regarded as solved for direct control of airplane motions, that is, for immediate operation of the control surfaces, they are not clarified as to oscillations, stability, and stress phenomena occurring in flight motions with Indirect control, as realized for instance in tab control" (p. 1).
Date: September 1949
Creator: Filzek, B.
Partner: UNT Libraries Government Documents Department

On the Installation of Jet Engine Nacelles on a Wing Fourth Partial Report: Pressure-Distribution Measurements on a Sweptback Wing with Jet Engine Nacelle

Description: "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.
Partner: UNT Libraries Government Documents Department

[Memorandums on the Subject of Wind Tunnel Measurements of the Henschel Missile "Zitterrochen"]

Description: "At the request of the Henschel Aircraft Works. A. G. Berlin. three models of the missile "Zitterrochen" were investigated at subsonic velocities.(open jet 215-millimeter diameter) and at supersonic velocities (open jet 110 by 130 millimeters) in order to determine the effect of various wing forms on the air forces and moments. Three-component measurements were taken, and one model was also investigated with deflected control plates" (p. 1).
Date: April 1948
Creator: Weber & Kehl
Partner: UNT Libraries Government Documents Department

Test Report on Three- and Six-Component Measurements on a Series of Tapered Wings of Small Aspect Ratio (Partial Report: Trapezoidal Wing)

Description: The present report, which forms the first of six articles on experiments with airfoils of aspect ratio from 1 to 3 and various planforms, deals with the three- and six-component measurements made on the trapezoidal wing series in the 2.15 x 3-meter wind tunnel of the DVL at the request of the Henschel Aircraft Company.
Date: May 1949
Creator: Lange & Wacke
Partner: UNT Libraries Government Documents Department

Fundamentals of the Control of Gas-Turbine Power Plants for Aircraft, Part 3: Control of Jet Engines

Description: "The basic principles of the control of TL engines are developed on the basis of a quantitative investigation of the behavior of these behavior under various operating conditions with particular consideration of the simplifications permissible in each case. Various possible means of control of jet engines are suggested and are illustrated by schematic designs" (p. 1).
Date: May 1947
Creator: Kühl, H.
Partner: UNT Libraries Government Documents Department

Fundamentals of the Control of Gas-Turbine Power Plants for Aircraft, Part 1: Standardization of the Computations Relating to the Control of Gas-Turbine Power Plants for Aircraft by the Employment of the Laws of Similarity

Description: "It will be shown that by the use of the concept of similarity a simple representation of the characteristic curves of a compressor operating in combination with a turbine may be obtained with correct allowance for the effect of temperature. Furthermore, it becomes possible to simplify considerably the rather tedious investigations of the behavior of gas-turbine power plants under different operating conditions. Characteristic values will be derived for the most important elements of operating behavior of the power plant, which will be independent of the absolute values of pressure and temperature" (p. 1).
Date: April 1947
Creator: Kühl, H.
Partner: UNT Libraries Government Documents Department

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

The Characteristics Method Applied to Stationary Two-Dimensional and Rotationally Symmetrical Gas Flows

Description: "By means of characteristics theory, formulas for the numerical treatment of stationary compressible supersonic flows for the two-dimensional and rotationally symmetrical cases have been obtained from their differential equations" (p. 1).
Date: March 1949
Creator: Pfeiffer, F. & Meyer-König, W.
Partner: UNT Libraries Government Documents Department