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 Decade: 1940-1949
 Year: 1947
 Collection: National Advisory Committee for Aeronautics Collection
Investigations of Compression Shocks and Boundary Layers in Gases Moving at High Speed

Investigations of Compression Shocks and Boundary Layers in Gases Moving at High Speed

Date: January 1, 1947
Creator: Ackeret, J.; Feldmann, F. & Rott, N.
Description: The mutual influences of compression shocks and friction boundary layers were investigated by means of high speed wind tunnels.Schlieren optics provided a clear picture of the flow phenomena and were used for determining the location of the compression shocks, measurement of shock angles, and also for Mach angles. Pressure measurement and humidity measurements were also taken into consideration.Results along with a mathematical model are described.
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The Calculation of Compressible Flows with Local Regions of Supersonic Velocity

The Calculation of Compressible Flows with Local Regions of Supersonic Velocity

Date: March 1, 1947
Creator: Goethert, B. & Kawalki, K. H.
Description: This report addresses a method for the approximate calculation of compressible flows about profiles with local regions of supersonic velocity. The flow around a slender profile is treated as an example.
Contributing Partner: UNT Libraries Government Documents Department
Drag Reduction by Suction of the Boundary Layer Separated Behind Shock Wave Formation at High Mach Numbers

Drag Reduction by Suction of the Boundary Layer Separated Behind Shock Wave Formation at High Mach Numbers

Date: July 1, 1947
Creator: Regenscheit, B.
Description: With an approach of the velocity of flight of a ship to the velocity of sound, there occurs a considerable increase of the drag. The reason for this must be found in the boundary layer separation caused by formation of shock waves. It will be endeavored to reduce the drag increase by suction of the boundary layer. Experimental results showed that drag increase may be considerably reduced by this method. It was, also, observed that, by suction, the position of shock waves can be altered to a considerable extent.
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Temperatures and Stresses on Hollow Blades For Gas Turbines

Temperatures and Stresses on Hollow Blades For Gas Turbines

Date: September 1, 1947
Creator: Pollmann, Erich
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 onthe heat transfer coefficients at the blade profile are supported by tests on an electrically heated blade model. The temperature distribution in the cross section of a blade Is thoroughly investigated and the temperature field determined for a special case. A method for calculation of the thermal stresses in turbine blades for a given temperature distribution is indicated. The effect of the heat radiation on the blade temperature also is dealt with. Test-stand experiments on turbine blades are evaluated, particularly with respect to temperature distribution in the cross section; maximum and minimum temperature in the cross section are ascertained. Finally, the application of the hollow blade for a stationary gas turbine is investigated. Starting from a setup for 550 C gas temperature the improvement of the thermal efficiency and the fuel consumption are considered as well as the increase of ...
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Investigations on Experimental Impellers for Axial Blowers

Investigations on Experimental Impellers for Axial Blowers

Date: April 1, 1947
Creator: Encke, W.
Description: A selection of measurements obtained on experimental impellers for axial blowers will be reported. In addition to characteristic curves plotted for low and for high peripheral velocities, proportions and blade sections for six different blower models and remarks on the design of blowers will be presented.
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The Flow Through Axial Turbine Stages of Large Radial Blade Length

The Flow Through Axial Turbine Stages of Large Radial Blade Length

Date: April 1, 1947
Creator: Eckert & Korbacher
Description: A calulation of the flow in turbine blading is reported that includes the calculation of effect of centrifugal force. Frictional losses on the stator blades and rotor blades are allowed.
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Gas-Dynamic Investigations of the Pulse-Jet Tube, Parts 1 and 2

Gas-Dynamic Investigations of the Pulse-Jet Tube, Parts 1 and 2

Date: February 1, 1947
Creator: Shultz-Grunow, F.
Description: Based upon a simplified representation of the mode of operation of the pulse-jet tube, the effect of the influences mentioned in the title were investigated and it will be shown that, for a jet tube with a fccmndesigned to be aerodynamically favorable, the ability to operate is at least questionable. By taking into account the course of the development of pressure by combustion, a new insight has been obtained into the processes of motion within the jet tube, an insight that explains a number of empirical observations, namely: certain particulars of the sequence of pressure variations; the existence of an optimum valve-opening ratio; the occurrence of an intrusion of air; and the existence of a flight speed above lrhichthe jet tube ceases to operate. At too great an opening ratio or at too great a flight s-peed, the continuous flow through the tube is too predominant over the oscilla~ory process to perinitthe occurrence of an explosion powerful enough to maintain continuous operation. Certain possible means of making the operation of the jet tube more independent of the flight speed and of reducing the flow losses were proposed and discussed.
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Theory of Wings in Nonstationary Flow

Theory of Wings in Nonstationary Flow

Date: June 1, 1947
Creator: Nekrasov, A. I.
Description: This paper gives an overview of equations for vibration and flutter affecting airplane wings in nonstationary flow.
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Possibilities of Reducing the Length of Axial Superchargers for Aircraft Motors

Possibilities of Reducing the Length of Axial Superchargers for Aircraft Motors

Date: January 1, 1947
Creator: Eckert, B.
Description: Axial blowers are gaining importance as aircraft engine superchargers. However, the pressure head obtainable per stage is small. Due to the necessary great number of stages, the physical length of the blower becomes too great for an airworthy device. This report discusses several types of construction that permit a reduction in the length of the blower.
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Investigations of effects of surface temperature and single roughness elements on boundary-layer transition

Investigations of effects of surface temperature and single roughness elements on boundary-layer transition

Date: January 1, 1947
Creator: Liepmann, Hans W & Fila, Gertrude H
Description: The laminar boundary layer and the position of the transition point were investigated on a heated flat plate. It was found that the Reynolds number of transition decreased as the temperature of the plate is increased. It is shown from simple qualitative analytical considerations that the effect of variable viscosity in the boundary layer due to the temperature difference produces a velocity profile with an inflection point if the wall temperature is higher than the free-stream temperature. This profile is confirmed by measurements. The instability of inflection-point profiles is discussed. Studies of the flow in the wake of large, two-dimensional roughness elements are presented. It is shown that a boundary-layer can separate and reattach itself to the wall without having transition take place.
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Calculations and Experimental Investigations on the Feed-Power Requirement of Airplanes with Boundary-Layer Control

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

Date: September 1, 1947
Creator: Krueger, W.
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.
Contributing Partner: UNT Libraries Government Documents Department
Report on Rocket Power Plants Based on T-Substance

Report on Rocket Power Plants Based on T-Substance

Date: July 1, 1947
Creator: Walter, Hellmuth
Description: In the search for an energy source independent of air for the propulsion of underwater craft, attention was early concentrated on T-substance. It was possible to convince the OKM [NACA comment: Navy High Command] very quickly of the importance of this material. In 1934, the first experiments were undertaken. A difficulty was at once presented by the limited concentration that had been attained. At first only 60 percent T-substance could be supplied; this amount was later increased to as much as 85 percent. Decomposition and combustion experiments conducted on the grounds of the CPVA in Kiel-Dietrichsdorf led to the first practical information as to the technical feasibility of the use of T-substance. New perspectives soon developed because a method of concentrated energy production had been found here, which was capable of many applications. The idea of using this energy for the propulsion of missiles either in guns or as rockets suggested itself and appropriate proposals, which quickly led to the construction of the first experimental devices, were made to the official quarters concerned. In January 1937, the first flight of a DVL aircraft with T-substance auxiliary propulsion took place at Alimbsmuhle in the presence of Colonel Udet, who piloted the ...
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Laboratory Report on the Investigation of the Flow around Two Turbine-Blade Profiles using the Interferometer Method

Laboratory Report on the Investigation of the Flow around Two Turbine-Blade Profiles using the Interferometer Method

Date: July 1, 1947
Creator: vonVietinghoff-Scheel, K.
Description: At the request of the Junkers Aircraft and Engine Construction Company, Engine Division, Dessau Main Plant, an investigation was made using the interferometer method on the two turbine-blade profiles submitted. The interferometer method enables making visible the differences in density and consequently the boundary layers that develop when a flow is directed on the profile. Recognition of the points on the profile at which separation of flow occurs is thus possible. By means of the interference photographs the extent of the dead-water region may be ascertained. The size of the dead-water region provides evidence as to the quality of the flow and allows a qualitative estimate of the amount of the flow losses. Interference photographs thus provide means of judging the utility of profiles under specific operating conditions and provide suggestions for possible changes of profile contours that might help to improve flow relations. Conclusions may be drawn concerning the influence of the blade-spacing ratio, the inlet-air angle, and the connection between the curvature of the profile contour and the point of separation of the flow from the profile surface.
Contributing Partner: UNT Libraries Government Documents Department
Some Aerodynamic Relations for an Airfoil in Oblique Flow

Some Aerodynamic Relations for an Airfoil in Oblique Flow

Date: June 1, 1947
Creator: Ringleb, F.
Description: Some aerodynamic relations are derived which exist between two infinitely long airfoils if one is in a straight flow and the other in oblique flow, and both present the same profile in the direction of flow.
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On the Problems of Chaplygin for Mixed Sub-and Supersonic Flows

On the Problems of Chaplygin for Mixed Sub-and Supersonic Flows

Date: January 1, 1947
Creator: Frankl, F.
Description: There are investigated the problems of the flow of a supersonic jet out of a vessel with plane side walls and the problem of the supersonic flow about a wedge when there is a zone of local subsonic velocities ahead of the wedge.
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Lift and Drag of Wings with Small Span

Lift and Drag of Wings with Small Span

Date: August 1, 1947
Creator: Weinig, F.
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.
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Test Report on Measurements on a Series of Tapered Wings of Small Aspect Ratio (Trapezoidal Wing with Fuselage)

Test Report on Measurements on a Series of Tapered Wings of Small Aspect Ratio (Trapezoidal Wing with Fuselage)

Date: July 1, 1947
Creator: Lange & Wacke
Description: This is the second of a series of six reports dealing with three- and six-component measurements on the tapering series at small aspect ratio. The present report concerns the trapezoidal wing with fuselage.
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Pressure-Distribution Measurements on a Straight and on a 35 Degree Swept-Back Tapered Wing

Pressure-Distribution Measurements on a Straight and on a 35 Degree Swept-Back Tapered Wing

Date: January 1, 1947
Creator: Thiel, A. & Weissinger, J.
Description: The spanwise lift-distribution measurements in straight air flow on a straight and a 35 deg swept-back tapered wing (NACA airfoil section 0012) are compared with theory for two angles of attack each (alpha approx. 6 deg and alpha approx. 12 deg) in the unstalled range of flow. The complete pressure distribution for the greater of the two angles is indicated.
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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

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

Date: April 1, 1947
Creator: Luehl, H.
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 bec~mes 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 valu:s of pressure and temperature. At the same time, the investigations provide the basis for scale-model tests on compressors and turbines.
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Calculation of the Pressure Distribution on Bodies of Revolution in the Subsonic Flow of a Gas, Part 1, Axially Symmetrical Flow

Calculation of the Pressure Distribution on Bodies of Revolution in the Subsonic Flow of a Gas, Part 1, Axially Symmetrical Flow

Date: July 1, 1947
Creator: Bilharz, Herbert & Hoelder, Ernst
Description: 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. This requirement yields for the "pseudo-stream function" psi a differential equation which must be fulfilled for as many points on the contour as source lengths are assumed. In this manner, the problem of defining the still unknown source intensities is reduced to the solution of an inhomogeneous equation system. The pressure distribution is then determined with the aid of Bernoulli's equation and adiabatic equation of state. Lastly, the pressure distributions in compressible and incompressible medium are compared on a model problem.
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Pressure-Distribution Measurements on Unyawed Swept-Back Wings

Pressure-Distribution Measurements on Unyawed Swept-Back Wings

Date: July 1, 1947
Creator: Jacobs, W.
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.
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Fundamentals of the Control of Gas-Turbine Power Plants for Aircraft. Part III Control of Jet Engines, Part 3, Control of Jet Engines

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

Date: May 1, 1947
Creator: Kuehl, H.
Description: The basic principles of the control of TL ongincs 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 pormissible in each case. Various possible means of control of jet engines are suggested and are illustrated by schematic designs.
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An Anaylsis of Control Requirements and Control Parameters for Direct-Coupled Turbojet Engines

An Anaylsis of Control Requirements and Control Parameters for Direct-Coupled Turbojet Engines

Date: January 1, 1947
Creator: Novik, David & Otto, Edward W.
Description: Requirements of an automatic engine control, as affected by engine characteristics, have been analyzed for a direct-coupled turbojet engine. Control parameters for various conditions of engine operation are discussed. A hypothetical engine control is presented to illustrate the use of these parameters. An adjustable speed governor was found to offer a desirable method of over-all engine control. The selection of a minimum value of fuel flow was found to offer a means of preventing unstable burner operation during steady-state operation. Until satisfactory high-temperature-measuring devices are developed, air-fuel ratio is considered to be a satisfactory acceleration-control parameter for the attainment of the maximum acceleration rates consistent with safe turbine temperatures. No danger of unstable burner operation exists during acceleration if a temperature-limiting acceleration control is assumed to be effective. Deceleration was found to be accompanied by the possibility of burner blow-out even if a minimum fuel-flow control that prevents burner blow-out during steady-state operation is assumed to be effective. Burner blow-out during deceleration may be eliminated by varying the value of minimum fuel flow as a function of compressor-discharge pressure, but in no case should the fuel flow be allowed to fall below the value required for steady-state burner operation.
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An Analysis of the Full-Floating Journal Bearing

An Analysis of the Full-Floating Journal Bearing

Date: January 28, 1947
Creator: Shaw, M.C. & Nussdorfer, T.J.
Description: An analysis of the operating characteristics of a full-floating bearing - a bearing in which a floating sleeve is located between the journal and bearing surfaces - is presented together with charts - from which the performance of such bearings may be predicted. Examples are presented to illustrate the use of these charts and a limited number of experiments conducted upon a glass full-floating bearing to verify some results of the analysis are reported. The floating sleeve can operate over a wide range of speeds for a given shaft speed, the exact value depending principally upon the ratio of clearances and upon the ratio of radii of the bearing. Lower operating temperatures at high rotative speeds are to be expected by using a full-floating bearing. This lower operating temperature would be obtained at the expense of the load-carrying capacity of the bearing if, for comparison, the clearances remain the same in both bearings. A full-floating bearing having the same load capacity as a conventional journal bearing may be designed if decreased clearances are allowable.
Contributing Partner: UNT Libraries Government Documents Department
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