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An Analysis of Supersonic Aerodynamic Heating With Continuous Fluid Injection (open access)

An Analysis of Supersonic Aerodynamic Heating With Continuous Fluid Injection

From Introduction: "The aerodynamic heating problem assumes considerable importance at high-supersonic speeds. Sanger and Bredt (reference 1) have calculated the high-speed aerodynamic forces and equilibrium surface temperature at extremely high altitudes where the molecular mean free path is large (free-molecule-flow region) compared with a characteristic body dimension. The theoretical investigation of Lees (reference 2) on the stability of the laminar boundary layer in compressible flow indicates that the laminar boundary layer is completely stable at all Reynolds numbers at supersonic speeds for a sufficiently low ratio of surface temperature to stream temperature."
Date: September 29, 1949
Creator: Klunker, E. B. & Ivey, H. Reese
System: The UNT Digital Library
An apparatus for varying effective dihedral in flight with application to a study of tolerable dihedral on a conventional fighter airplane (open access)

An apparatus for varying effective dihedral in flight with application to a study of tolerable dihedral on a conventional fighter airplane

From Summary: "An apparatus for varying effective dihedral in flight by means of servo actuation of the ailerons in response to sideslip angle is described. The results of brief flight tests of the apparatus on a conventional fighter airplane are presented and discussed. The results of an investigation employing the apparatus to determine the tolerable (safe for normal fighter operation) range of effective dihedral on the test airplane are presented."
Date: August 24, 1949
Creator: Kauffman, William M.; Liddell, Charles J., Jr.; Smith, Allan & Van Dyke, Rudolph D., Jr.
System: The UNT Digital Library
Application of Radial-Equilibrium Condition to Axial-Flow Compressor and Turbine Design (open access)

Application of Radial-Equilibrium Condition to Axial-Flow Compressor and Turbine Design

"Basic general equations governing the three-dimensional compressible flow of gas through a compressor or turbine are given in terms of total enthalpy, entropy, and velocity components of the gas. Two methods of solution are obtained for the simplified, steady axially symmetric flow; one involves the use of a number of successive planes normal to the axis of the machine and short distances apart, and the other involves only three stations for a stage in which an appropriate radial-flow path is used. Methods of calculation for the limiting cases of zero and infinite blade aspect ratios and an approximate method of calculation for finite blade aspect ratio are also given" (p. 1).
Date: January 1, 1949
Creator: Wu, Chung-Hua & Wolfenstein, Lincoln
System: The UNT Digital Library
The application of the statistical theory of extreme values to gust-load problems (open access)

The application of the statistical theory of extreme values to gust-load problems

From Introduction: "Recent developments in the statistical theory of extreme values (references 4 to 10) have indicated a somewhat more rational approach to the problem of predicting the probability of occurrence The present report summarizes some of these findings, indicates the method of application, and evaluates their applicability to certain gust-load problems ."
Date: July 22, 1949
Creator: Press, Harry
System: The UNT Digital Library
Attainable Circulation About Airfoils in Cascade (open access)

Attainable Circulation About Airfoils in Cascade

"From consideration of available information on boundary-layer behavior, a relation among profile thickness, maximum surface velocity, Reynolds number, velocity diagram, and solidity is established for a cascade of airfoils immersed in a two-dimensional incompressible fluid flow. Several cascades are computed to show the effect of various cascade design parameters on minimum required cascade solidity. Comparisons with experimentally determined blade performance show that the derived blade loadings are equal or higher for moderate flow deceleration and somewhat lower for large deceleration. Blades with completely laminar flow appear practical for impulse or reaction blading" (p. 117).
Date: September 1949
Creator: Goldstein, Arthur W. & Mager, Artur
System: The UNT Digital Library
Characteristics of Low-Aspect-Ratio Wings at Supercritical Mach Numbers (open access)

Characteristics of Low-Aspect-Ratio Wings at Supercritical Mach Numbers

"The separation of the flow over wings precipitated by the compression shock that forms as speeds are increased into the supercritical Mach number range has imposed serious difficulties in the improvement of aircraft performance. Three difficulties rise principally as a consequence of the rapid drag rise and the loss of lift that causes serious stability changes when the wing shock-stalls. Favorable relieving effects due to the three-dimensional flow around the tips were obtained and these effects were of such magnitude that it is indicated that low-aspect-ratio wings offer a possible solution of the problems encountered" (p. 1).
Date: 1949
Creator: Stack, John & Lindsey, W. F.
System: The UNT Digital Library
Constant-Pressure Combustion Charts Including Effects of Diluent Addition (open access)

Constant-Pressure Combustion Charts Including Effects of Diluent Addition

"Charts are presented for the calculation of (a) the final temperatures and the temperature changes involved in constant-pressure combustion processes of air and in products of combustion of air and hydrocarbon fuels, and (b) the quantity of hydrocarbon fuels required in order to attain a specified combustion temperature when water, alcohol, water-alcohol mixtures, liquid ammonia, liquid carbon dioxide, liquid nitrogen, liquid oxygen, or their mixtures are added to air as diluents or refrigerants. The ideal combustion process and combustion with incomplete heat release from the primary fuel and from combustible diluents are considered" (p. 1).
Date: 1949
Creator: Turner, L. Richard & Bogart, Donald
System: The UNT Digital Library
Correlation of Physical Properties With Molecular Structure for Some Dicyclic Hydrocarbons Having High Thermal-Energy Release Per Unit Volume (open access)

Correlation of Physical Properties With Molecular Structure for Some Dicyclic Hydrocarbons Having High Thermal-Energy Release Per Unit Volume

"As part of a program to study the correlation between molecular structure and physical properties of high-density hydrocarbons, the net heats of combustion, melting points, boiling points, densities, and kinematic viscosities of some hydrocarbons in the 2-n-alkylbiphenyl, 1,1-diphenylalkane, diphenylalkane, 1,1-dicyclohexylalkane, and dicyclohexylalkane series are presented" (p. 55).
Date: June 20, 1949
Creator: Wise, P. H.; Serijan, K. T. & Goodman, I. A.
System: The UNT Digital Library
Critical Stress of Ring-Stiffened Cylinders in Torsion (open access)

Critical Stress of Ring-Stiffened Cylinders in Torsion

"A chart in terms of nondimensional parameters is presented for the theoretical critical stress in torsion of simply supported cylinders stiffened by identical equally spaced rings of zero torsional stiffness. The results are obtained by solving the equation of equilibrium by means of the Galerkin method. Comparison of the theoretical results with experimental results indicates that ring-stiffened cylinders buckle, on the average, at a buckling stress about 15 percent below the theoretical buckling stress" (p. 1).
Date: November 1949
Creator: Stein, Manuel; Sanders, J. Lyell, Jr. & Crate, Harold
System: The UNT Digital Library
The design of low-turbulence wind tunnels (open access)

The design of low-turbulence wind tunnels

From Summary: "Within the past 10 years there have been placed in operation in the United States four low-turbulence wind tunnels of moderate cross-sectional area and speed, one at the National Bureau of Standards, two at the NACA Langley Laboratory, and one at the NACA Ames Laboratory. This paper reviews briefly the state of knowledge and those features which make possible the attainment of low turbulence in wind tunnels. Specific applications to two wind tunnels are described."
Date: 1949
Creator: Dryden, Hugh L. & Abbott, Ira H.
System: The UNT Digital Library
The development of cambered airfoil sections having favorable lift characteristics at supercritical Mach numbers (open access)

The development of cambered airfoil sections having favorable lift characteristics at supercritical Mach numbers

Several groups of new airfoil sections, designated as the NACA 8-series, are derived analytically to have lift characteristics at supercritical Mach numbers which are favorable in the sense that the abrupt loss of lift, characteristic of the usual airfoil section at Mach numbers above the critical, is avoided. Aerodynamic characteristics determined from two-dimensional wind-tunnel tests at Mach numbers up to approximately 0.9 are presented for each of the derived airfoils. Comparisons are made between the characteristics of these airfoils and the corresponding characteristics of representative NACA 6-series airfoils.
Date: 1949
Creator: Graham, Donald J.
System: The UNT Digital Library
Direct method of design and stress analysis of rotating disks with temperature gradient (open access)

Direct method of design and stress analysis of rotating disks with temperature gradient

A method is presented for the determination of the contour of disks, typified by those of aircraft gas turbines, to incorporate arbitrary elastic-stress distributions resulting from either centrifugal or combined centrifugal and thermal effects. The specified stress may be radial, tangential, or any combination of the two. Use is made of the finite-difference approach in solving the stress equations, the amount of computation necessary in the evolution of a design being greatly reduced by the judicious selection of point stations by the aid of a design chart. Use of the charts and of a preselected schedule of point stations is also applied to the direct problem of finding the elastic and plastic stress distribution in disks of a given design, thereby effecting a great reduction in the amount of calculation. Illustrative examples are presented to show computational procedures in the determination of a new design and in analyzing an existing design for elastic stress and for stresses resulting from plastic flow.
Date: April 4, 1949
Creator: Manson, S. S.
System: The UNT Digital Library
Dynamics of a turbojet engine considered as a quasi-static system (open access)

Dynamics of a turbojet engine considered as a quasi-static system

From Summary: "A determination of the dynamic characteristics of a typical turbojet engine with a centrifugal compressor, a sonic-flow turbine-nozzle diaphragm, and fixed area exhaust nozzle is presented. A generalized equation for transient behavior of the engine was developed; this equation was then verified by calculations using compressor and turbine performance charts extrapolated from equilibrium operating data and by experimental data obtained from an engine operated under transients in fuel flow."
Date: July 27, 1949
Creator: Otto, Edward W. & Taylor, Burt L., III
System: The UNT Digital Library
The effect of blade-section thickness ratio on the aerodynamic characteristics of related full-scale propellers at Mach numbers up to 0.65 (open access)

The effect of blade-section thickness ratio on the aerodynamic characteristics of related full-scale propellers at Mach numbers up to 0.65

The results of an investigation of two 10-foot-diameter, two-blade NACA propellers are presented for a range of blade angles from 20 degrees to 55 degrees at airspeeds up to 500 miles per hour. These results are compared with those from previous investigations of five related NACA propellers in order to evaluate the effects of blade-section thickness ratios on propeller aerodynamic characteristics.
Date: April 25, 1949
Creator: Maynard, Julian D. & Steinberg, Seymour
System: The UNT Digital Library
Effect of Reynolds Number in Turbulent-Flow Range on Flame Speeds of Bunsen Burner Flames (open access)

Effect of Reynolds Number in Turbulent-Flow Range on Flame Speeds of Bunsen Burner Flames

"The effect of flow conditions on the geometry of the turbulent Bunsen flame was investigated. Turbulent flame speed is defined in terms of flame geometry and data are presented showing the effect of Reynolds number of flow in the range of 3000 to 35,000 on flame speed for burner diameters from 1/4 to 1 1/8 inches and three fuels -- acetylene, ethylene, and propane. The normal flame speed of an explosive mixture was shown to be an important factor in determining its turbulent flame speed, and it was deduced from the data that turbulent flame speed is a function of both the Reynolds number of the turbulent flow in the burner tube and of the tube diameter" (p. 1).
Date: 1949
Creator: Bollinger, Lowell M. & Williams, David T.
System: The UNT Digital Library
The effect of torsional flexibility on the rolling characteristics at supersonic speeds of tapered unswept wings (open access)

The effect of torsional flexibility on the rolling characteristics at supersonic speeds of tapered unswept wings

From Summary: "An analysis is presented of the effect of torsional flexibility on the rolling characteristics at supersonic speeds of tapered unswept wings with partial-span constant-percent-chord ailerons extending inboard from the wing tip. The geometric variables considered are aspect ratio, taper ratio, aileron span, and aileron chord. The shape of the wing-torsional-stiffness curve is assumed and the twisting moment is considered to result solely from the pressure distribution caused by aileron deflection, so that the necessity of using a successive-approximation method is avoided."
Date: March 8, 1949
Creator: Tucker, Warren A. & Nelson, Robert L.
System: The UNT Digital Library
Effect of tunnel configuration and testing technique on cascade performance (open access)

Effect of tunnel configuration and testing technique on cascade performance

"An investigation has been conducted to determine the influence of aspect ratio, boundary-layer control by means of slots and porous surfaces, Reynolds number, and tunnel end-wall condition upon the performance of airfoils in cascades. A representative compressor-blade section (the NACA 65-(12)(10) of aspect ratios of 1, 2, and 4 has been tested at low speeds in cascades with solid and with porous side walls. Two-dimensional flow was established in porous-wall cascades of each of the three aspect ratios tested; the flow was not two-dimensional in any of the solid-wall cascades" (p. 263).
Date: November 30, 1949
Creator: Erwin, John R. & Emery, James C.
System: The UNT Digital Library
Effects of wing flexibility and variable air lift upon wing bending moment during landing impacts of a small seaplane (open access)

Effects of wing flexibility and variable air lift upon wing bending moment during landing impacts of a small seaplane

From Summary: "A smooth-water-landing investigation was conducted with a small seaplane to obtain experimental wing-bending-moment time histories together with time histories of the various parameters necessary for the prediction of wing bending moments during hydrodynamic forcing functions. The experimental results were compared with calculated results which include inertia-load effects and the effects of air-load variation during impact. The responses of the fundamental mode were calculated with the use of the measured hydrodynamic forcing functions. From these responses, the wing bending moments due to the hydrodynamic load were calculated according to the procedure given in R.M. No. 2221. The comparison of the time histories of the experimental and calculated wing bending moments showed good agreement both in phase relationship of the oscillations and in numerical values."
Date: December 21, 1949
Creator: Merten, Kenneth F. & Beck, Edgar B.
System: The UNT Digital Library
Equilibrium Operating Performance of Axial-Flow Turbojet Engines by Means of Idealized Analysis (open access)

Equilibrium Operating Performance of Axial-Flow Turbojet Engines by Means of Idealized Analysis

"A method of predicting equilibrium operating performance of turbojet engines has been developed, with the assumption of simple model processes for the components. Results of the analysis are plotted in terms of dimensionless parameters comprising critical engine dimensions and over-all operating variables. This investigation was made of an engine in which the ratio of axial inlet-air velocity to compressor-tip velocity is constant, which approximates turbojet engines with axial-flow compressors" (p. 673).
Date: February 25, 1949
Creator: Sanders, John C. & Chapin, Edward C.
System: The UNT Digital Library
Frequency Response of Linear Systems From Transient Data (open access)

Frequency Response of Linear Systems From Transient Data

"Methods are presented that use general correlative time-response input and output data for a linear system to determine the frequency-response function of that system. These methods give an exact description of any linear system for which such transient data are available. Examples are shown of application of a method to both an underdamped and a critically damped exact second-order system, and to an exact first-order system with and without dead time. Experimental data for a turbine-propeller engine showing the response of engine speed to change in propeller-blade angle are presented and analyzed" (p. 547).
Date: April 1, 1949
Creator: LaVerne, Melvin E. & Boksenbom, Aaron S.
System: The UNT Digital Library
Fundamental effects of aging on creep properties of solution-treated low-carbon N-155 alloy (open access)

Fundamental effects of aging on creep properties of solution-treated low-carbon N-155 alloy

A method is developed whereby the fundamental mechanisms are investigated by which processing, heat treatment, and chemical composition control the properties of alloys at high temperatures. The method used metallographic examination -- both optical and electronic --studies of x-ray diffraction-line widths, intensities, and lattice parameters, and hardness surveys to evaluate fundamental structural conditions. Mechanical properties at high temperatures are then measured and correlated with these measured structural conditions. In accordance with this method, a study was made of the fundamental mechanism by which aging controlled the short-time creep and rupture properties of solution-treated low-carbon n-155 alloy at 1200 degrees F.
Date: January 18, 1949
Creator: Frey, D. N.; Freeman, J. W. & White, A. E.
System: The UNT Digital Library
General algebraic method applied to control analysis of complex engine types (open access)

General algebraic method applied to control analysis of complex engine types

"A general algebraic method of attack on the problem of controlling gas-turbine engines having any number of independent variables was utilized employing operational functions to describe the assumed linear characteristics for the engine, the control, and the other units in the system. Matrices were used to describe the various units of the system, to form a combined system showing all effects, and to form a single condensed matrix showing the principal effects. This method directly led to the conditions on the control system for noninteraction so that any setting disturbance would affect only its corresponding controlled variable" (p. 581).
Date: April 25, 1949
Creator: Boksenbom, Aaron S. & Hood, Richard
System: The UNT Digital Library
General Theory of Aerodynamic Instability and the Mechanism of Flutter (open access)

General Theory of Aerodynamic Instability and the Mechanism of Flutter

"The aerodynamic forces on an oscillating airfoil or airfoil-aileron combination of three independent degrees of freedom have been determined. The problem resolves itself into the solution of certain definite integrals, which have been identified as Bessel functions of the first and second kind and of zero and first order. The theory, being based on potential flow and the Kutta condition, is fundamentally equivalent to the conventional wing-section theory relating to the steady case" (p. 23).
Date: 1949
Creator: Theodorsen, Theodore
System: The UNT Digital Library
Heat transfer to bodies traveling at high speed in the upper atmosphere (open access)

Heat transfer to bodies traveling at high speed in the upper atmosphere

A general method has been developed, using the methods of kinetic theory, whereby the surface temperatures of bodies can be calculated for steady flight at any speed in a rarefied gas. The particular solution was made for a flat plate; however, the calculations can be easily extended to bodies of arbitrary shape.
Date: 1949
Creator: Stalder, Jackson R. & Jukoff, David
System: The UNT Digital Library