National Advisory Committee for Aeronautics (NACA) - 79 Matching Results

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Analytical Treatment of Normal Condensation Shock

Description: "The condensation of water vapor in an air has the following 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" (p. 1).
Date: July 1947
Creator: Heybey
Partner: UNT Libraries Government Documents Department

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

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" (p. 1).
Date: July 1947
Creator: Bilharz, Herbert & Hölder, Ernst
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

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

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" (p. 1).
Date: June 1947
Creator: Kovasznay, Laszlo
Partner: UNT Libraries Government Documents Department

The Combination of Internal-Combustion Engine and Gas Turbine

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" (p. 1).
Date: April 1947
Creator: Zinner, K.
Partner: UNT Libraries Government Documents Department

Compression Shocks of Detached Flow

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" (p. 1).
Date: June 1947
Creator: Eggink
Partner: UNT Libraries Government Documents Department

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

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" (p. 1).
Date: August 1947
Creator: Fuchs, N.
Partner: UNT Libraries Government Documents Department

Cones in Supersonic Flow

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" (p. 1).
Date: August 1947
Creator: Hantzsche, W. & Wendt, H.
Partner: UNT Libraries Government Documents Department

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

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.
Date: June 1947
Creator: Denkmeier, H. & Gross, K.
Partner: UNT Libraries Government Documents Department

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

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.
Date: September 1947
Creator: Weigand, A.
Partner: UNT Libraries Government Documents Department

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

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" (p. 1).
Date: September 1947
Creator: Zobel
Partner: UNT Libraries Government Documents Department

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

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" (p. 1).
Date: April 1947
Creator: Vogt, F.
Partner: UNT Libraries Government Documents Department

Drag Corrections in High-Speed Wind Tunnels

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.
Date: July 1947
Creator: Ludwieg, H.
Partner: UNT Libraries Government Documents Department

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

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" (p. 1).
Date: July 1947
Creator: Regenscheit, B.
Partner: UNT Libraries Government Documents Department

The Effect of Turbulence on the Flame Velocity in Gas Mixtures

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" (p. 1).
Date: April 1947
Creator: Damköhler, Gerhard
Partner: UNT Libraries Government Documents Department

The Elasto-Plastic Stability of Plates

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.
Date: December 1947
Creator: Ilyushin, A. A.
Partner: UNT Libraries Government Documents Department

Equations for Adiabatic but Rotational Steady Gas Flows Without Friction

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.
Date: August 1947
Creator: Schäefer, Manfred
Partner: UNT Libraries Government Documents Department

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

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.
Date: March 1947
Creator: Lemme, H. G.
Partner: UNT Libraries Government Documents Department

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

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" (p. 1).
Date: March 1947
Creator: Lemme, H. A.
Partner: UNT Libraries Government Documents Department

Fundamental Aerodynamic Investigations for Development of Arrow-Stabilized Projectiles

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" (p. 1).
Date: December 1947
Creator: Kurzweg, Hermann
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