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 Decade: 1940-1949
 Year: 1947
 Serial/Series Title: NACA Technical Memorandums
 Collection: National Advisory Committee for Aeronautics Collection
Analytical Treatment of Normal Condensation Shock

Analytical Treatment of Normal Condensation Shock

Date: July 1, 1947
Creator: Heybey
Description: The condensation of water vapor in an air consequences: acquisition of heat (liberated heat vaporization; loss of mass on the part of the flowing gas (water vapor is converted to liquid); change in the specific gas constants and of the ratio k of the specific heats (caused by change of gas composition). A discontinuous change of state is therefore connected with the condensation; schlieren photographs of supersonic flows in two-dimensional Laval nozzles show two intersecting oblique shock fronts that in the case of high humidities may merge near the point of intersection into one normal shock front.
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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.
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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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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.
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Calibration and Measurement in Turbulence Research by the Hot-Wire Method

Calibration and Measurement in Turbulence Research by the Hot-Wire Method

Date: June 1, 1947
Creator: Kovasznay, Kaszlo
Description: The problem of turbulence in aerodynamics is at present being attacked both theoretically and experimentally. In view of the fact however that purely theoretical considerations have not thus far led to satisfactory results the experimental treatment of the problem is of great importance. Among the different measuring procedures the hot wire methods are so far recognized as the most suitable for investigating the turbulence structure. The several disadvantages of these methods however, in particular those arising from the temperature lag of the wire can greatly impair the measurements and may easily render questionable the entire value of the experiment. The name turbulence is applied to that flow condition in which at any point of the stream the magnitude and direction of the velocity fluctuate arbitrarily about a well definable mean value. This fluctuation imparts a certain whirling characteristic to the flow.
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Coefficient of Friction, Oil Flow and Heat Balance of a Full-Journal Bearing

Coefficient of Friction, Oil Flow and Heat Balance of a Full-Journal Bearing

Date: October 1, 1947
Creator: Orloff, P. I.
Description: None
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The Combination of Internal-Combustion Engine and Gas Turbine

The Combination of Internal-Combustion Engine and Gas Turbine

Date: April 1, 1947
Creator: Zinner, K.
Description: While the gas turbine by itself has been applied in particular cases for power generation and is in a state of promising development in this field, it has already met with considerable success in two cases when used as an exhaust turbine in connection with a centrifugal compressor, namely, in the supercharging of combustion engines and in the Velox process, which is of particular application for furnaces. In the present paper the most important possibilities of combining a combustion engine with a gas turbine are considered. These "combination engines " are compared with the simple gas turbine on whose state of development a brief review will first be given. The critical evaluation of the possibilities of development and fields of application of the various combustion engine systems, wherever it is not clearly expressed in the publications referred to, represents the opinion of the author. The state of development of the internal-combustion engine is in its main features generally known. It is used predominantly at the present time for the propulsion of aircraft and road vehicles and, except for certain restrictions due to war conditions, has been used to an increasing extent in ships and rail cars and in some fields ...
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Compression Shocks of Detached Flow

Compression Shocks of Detached Flow

Date: June 1, 1947
Creator: Eggink
Description: It is known that compression shocks which lead from supersonic to subsonic velocity cause the flow to separate on impact on a rigid wall. Such shocks appear at bodies with circular symmetry or wing profiles on locally exceeding sonic velocity, and in Laval nozzles with too high a back pressure. The form of the compression shocks observed therein is investigated.
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Concerning the Velocity of Evaporation of Small Droplets in a Gas Atmosphere

Concerning the Velocity of Evaporation of Small Droplets in a Gas Atmosphere

Date: August 1, 1947
Creator: Fuchs, N.
Description: 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. The question at hand, and also the equivalent question of the velocity of growth of droplets in a supersaturated atmosphere, is highly significant in meteorology and for certain industrial purposes. Since the literature concerning this is very insufficient and many important aspects either are not considered at all or are reported incorrectly, it seems that a short discussion is not superfluous. A special consideration will be given to the various assumptions and neglections that are necessary in deriving the fundamental equation of Maxwell. The experimental work available, which is very insufficient and in part poorly dependable, can be used as an accurate check on the theory only in very few cases.
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Cones in Supersonic Flow

Cones in Supersonic Flow

Date: August 1, 1947
Creator: Hantzsche, W. & Wendt, H.
Description: 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.
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Description of Russian Aircraft Engines "AM 35" and "AM 38"

Description of Russian Aircraft Engines "AM 35" and "AM 38"

Date: June 1, 1947
Creator: Denkmeier, H. & Gross, K.
Description: The Russian AM 35 and AM 38 aircraft engines have superchargers with a swirl throttle, which appears to be a purely Russian development. This paper gives the results of test runs of the two engines, including the effects of the swirl throttle on engine performance.
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Determination of the Stress Concentration Factor of a Stepped Shaft Stressed in Torsion by Means of Precision Strain Gages

Determination of the Stress Concentration Factor of a Stepped Shaft Stressed in Torsion by Means of Precision Strain Gages

Date: September 1, 1947
Creator: Weigand, A.
Description: The stress distribution in stepped shafts stressed in torsion is determined by means of the electric precision strain gage the stress concentration factor is ascertained from the measurements. It is shown that the test values always are slightly lower than the values resulting from an approximate formula.
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Development and Construction of an Interferometer for Optical Measurements of Density Fields

Development and Construction of an Interferometer for Optical Measurements of Density Fields

Date: September 1, 1947
Creator: Zobel, Th.
Description: A method of interference is described in the present report which promises profitable application in aeronautical research. The physical foundation of the method and a simple method of adjustment are briefly discussed. The special technical construction of the instrument is described which guarantees its use also in the case of vibrations of the surrounding space and permits the investigation of unsteady phenomena. It is found that the interference method will make the small differences in density in the flow field around the body even at low speeds. (40 m/sec) optically measurable.
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The Distribution of Loads on Rivets Connecting a Plate to a Beam under Transverse Loads

The Distribution of Loads on Rivets Connecting a Plate to a Beam under Transverse Loads

Date: April 1, 1947
Creator: Vogt, F.
Description: This report gives theoretical discussion of the distribution of leads on rivets connecting a plate to a beam under transverse leads. Two methods of solution are given which are applicable to loads up to the limit of proportionality; in the first the rivets are treated as discrete members, and in the second they are replaced by a continuous system of jointing. A method of solution is also given which is applicable to the case when nonlinear deformations occur in the rivets and the plate, but not in the beam. The methods are illustrated by numerical examples, and these show that the loads carried by the rivets and the plate are less than the values given by classical theory, which does not take into account the slip of the rivets, even below the limit of proportionality. The difference is considerably accentuated when nonlinear deformations occur in the restructure and the beam then carries the greater portion of the bending moment. If the material of the beam has a higher proportional limit and a higher ultimate strength than the material of the plate, there is thus a transfer of load from weaker to stronger material, and this is to the advantage of ...
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Drag Corrections in High-Speed Wind Tunnels

Drag Corrections in High-Speed Wind Tunnels

Date: July 1, 1947
Creator: Ludwieg, H.
Description: In the vicinity of a body in a wind tunnel the displacement effect of the wake, due to the finite dimensions of the stream, produces a pressure gradient which evokes a change of drag. In incompressible flow this change of drag is so small, in general, that one does not have to take it into account in wind-tunnel measurements; however, in compressible flow it beoomes considerably larger, so that a correction factor is necessary for measured values. Correction factors for a closed tunnel and an open jet with circular cross sections are calculated and compared with the drag - corrections already bown for high-speed tunnnels.
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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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The Effect of Turbulence on the Flame Velocity in Gas Mixtures

The Effect of Turbulence on the Flame Velocity in Gas Mixtures

Date: April 1, 1947
Creator: Damkoehler, Gerhard
Description: The present report deals with the effect of turbulence on the propagation of the flame. Being based upon experiments with laminar as well as turbulent Bunsen flames, both the physico-chemical and the hydro-dynamical aspects of the problem are analyzed. A number of new deductions, interesting from the point of view of engine combustion and other very rapidly changing flame reactions, are made.
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The Elasto-Plastic Stability of Plates

The Elasto-Plastic Stability of Plates

Date: December 1, 1947
Creator: Ilyushin, A. A.
Description: This article explains results developed from the following research: 'The Stability of Plates and Shells beyond the Elastic Limit.' A significant improvement is found in the derivation of the relations between the stress factors and the strains resulting from the instability of plates and shells. In a strict analysis, the problem reduces to the solution of two simultaneous nonlinear partial differential equations of the fourth order in the deflection and stress function, and in the approximate analysis to a single linear equation of the Bryan type. Solutions are given for the special cases of a rectangular plate buckling into a cylindrical form, and of an arbitrarily shaped plate under uniform compression. These solutions indicate that the accuracy obtained by the approximate method is satisfactory.
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Equations for Adiabatic but Rotational Steady Gas Flows without Friction

Equations for Adiabatic but Rotational Steady Gas Flows without Friction

Date: August 1, 1947
Creator: Schaefer, Manfred
Description: 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. 2) The gas behaves adiabatically, not during the compression shock itself but both before and after the shock. However, the adiabatic equation (p/rho(sup kappa) = C) is not valid for the entire gas flow with the same constant C but rather with an appropriate individual constant for each portion of the gas. For steady flows, this means that the constant C of the adiabatic equation is a function of the stream function. Consequently, a gas that has been flowing "isentropically",that is, with the same constant C of the adiabatic equation throughout (for example, in origination from a region of constant density, temperature, and velocity) no longer remains isentropic after a compression shock if the compression shock is not extremely simple (wedge shaped in a two-dimensional flow or cone shaped in ...
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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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Force and pressure-distribution measurements on a rectangular wing with a slotted droop nose and with either plain and split flaps in combination or a slotted flap.

Force and pressure-distribution measurements on a rectangular wing with a slotted droop nose and with either plain and split flaps in combination or a slotted flap.

Date: March 1, 1947
Creator: Lemme, H G
Description: Force measurements and pressure distribution measurements on the midsection were made on a rectangular wing with slotted droop nose and end plates, on which could be placed a choice of either a plain flap-split flap combination or a slotted flap. (author).
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Force and Pressure-Distribution Measurements on a Rectangular Wing with Double-Hinged Nose

Force and Pressure-Distribution Measurements on a Rectangular Wing with Double-Hinged Nose

Date: March 1, 1947
Creator: Lemme, H. A.
Description: The previous measurements on airfoils with hinged nose disclosed a comparatively large low-pressure peak at the bend of the hinged nose; which favored the separation of flow. It was therefore attempted to reduce these low-pressure peaks by reducing the camber of the forward profile and thereby ensure a longer adherence of the flow and a maximum lift increase. The forces were measured on a rectangular wing with double-hinged nose and end plates, the pressure distributions were measured in the center section of the wing. The measurements disclosed that the highest lift attained with a single-hinged nose cannot be increased by a double-hinged nose. The sum of the deflection angles of both hinged noses related to the maximum lift is about equal to the corresponding angle of the single-hinge nose (approx. 30 deg to 40). The respective angle of attack in both cases amounts to approx. 21 deg. Even the low-pressure peak is about the same in both cases (P/q approx. -5.5). Therefore, a milder curvature of the forward portion of the profile affords no definite increase of the maximum lift.
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Fundamental Aerodynamic Investigations for Development of Arrow-Stabilized Projectiles

Fundamental Aerodynamic Investigations for Development of Arrow-Stabilized Projectiles

Date: December 1, 1947
Creator: Kurzweg, Hermann
Description: The numerous patent applications on arrow-stabilized projectiles indicate that the idea of projectiles without spin is not new, but has appeared in various proposals throughout the last decades. As far as projectiles for subsonic speeds are concerned, suitable shapes have been developed for sometime, for example, numerous grenades. Most of the patent applications, though, are not practicable particularly for projectiles with supersonic speed. This is because the inventor usually does not have any knowledge of aerodynamic flow around the projectile nor any particular understanding of the practical solution. The lack of wind tunnels for the development of projectiles made it necessary to use firing tests for development. These are obviously extremely tedious or expensive and lead almost always to failures. The often expressed opinion that arrow-stabilized projectiles cannot fly supersonically can be traced to this condition. That this is not the case has been shown for the first time by Roechling on long projectiles with foldable fins. Since no aerodynamic investigations were made for the development of these projectiles, only tedious series of firing tests with systematic variation of the fins could lead to satisfactory results. These particular projectiles though have a disadvantage which lies in the nature cf foldable ...
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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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