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Two-dimensional unsteady lift problems in supersonic flight

Description: The variation of pressure distribution is calculated for a two-dimensional supersonic airfoil either experiencing a sudden angle-of-attack change or entering a sharp-edge gust. From these pressure distributions the indicial lift functions applicable to unsteady lift problems are determined for two cases. Results are presented which permit the determination of maximum increment in lift coefficient attained by an unrestrained airfoil during its flight through a gust. As an application of these re… more
Date: December 5, 1947
Creator: Heaslet, Max A. & Lomax, Harvard
Partner: UNT Libraries Government Documents Department
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Investigation in the Langley 19-foot pressure tunnel of two wings of NACA 65-210 and 64-210 airfoil sections with various type flaps

Description: Report presents the results of an investigation conducted in the Langley 19-foot pressure tunnel to determine the maximum lift and stalling characteristics of two thin wings equipped with several types of flaps. Split, single slotted, and double slotted flaps were tested on one wing which had NACA 65-210 airfoil sections and split and double slotted flaps were tested on the other, which had NACA 64-210 airfoil sections. Both wings were zero sweep, an aspect ratio of 9, and a taper ratio of 0.4.
Date: August 19, 1947
Creator: Sivells, James C. & Spooner, Stanley H.
Partner: UNT Libraries Government Documents Department
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Effect of afterbody length and keel angle on minimum depth of step for landing stability and on take-off stability of a flying boat

Description: From Summary: "Tests were made to fill partly the need for information on the effect of afterbody dimensions on the hydrodynamic stability of a flying boat in smooth water. The dimensions investigated were depth of step, angle of afterbody keel, and length of afterbody. An analysis of the data showed that as either the afterbody length or keel angle was increased an accompanying increase in depth of step was required in order to maintain adequate landing stability."
Date: November 13, 1947
Creator: Olson, Roland E. & Land, Norman S.
Partner: UNT Libraries Government Documents Department
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Analysis of effect of basic design variables on subsonic axial-flow-compressor performance

Description: From Summary: "A blade-element theory for axial-flow compressors has been developed and applied to the analysis of the effects of basic design variables such as Mach number, blade loading, and velocity distribution on compressor performance. The relations among several efficiencies useful in compressor design are derived and discussed. The possible gains in useful operating range obtainable by the use of adjustable stator blades are discussed and a rapid approximate method of calculating blade-… more
Date: November 26, 1947
Creator: Sinnette, John T., Jr.
Partner: UNT Libraries Government Documents Department
open access

Subsonic flow over thin oblique airfoils at zero lift

Description: A previous report gave calculations for the pressure distribution over thin oblique airfoils at supersonic speed. The present report extends the calculations to subsonic speeds. It is found that the flows again can be obtained by the superposition of elementary conical flow fields. In the case of the swept-back wing the pressure distributions remain qualitatively similar at subsonic and supersonic speeds. Thus a distribution similar to the Ackeret type of distribution appears on the root sectio… more
Date: May 1947
Creator: Jones, Robert T.
Partner: UNT Libraries Government Documents Department
open access

Stability derivatives of triangular wings at supersonic speeds

Description: "The analysis of the stability derivatives of low-aspect-ratio triangular wings at subsonic and supersonic speeds, given in NACA TN no. 1423, is extended to apply to triangular wings having large vertex angles and traveling at supersonic speeds. The lift, rolling moment due to sideslip, and damping in roll and pitch for this more general case have been treated elsewhere on the basis of the theory of small disturbances. The surface potentials for angle of attack and rolling taken therefrom are u… more
Date: November 6, 1947
Creator: Ribner, Herbert S. & Malvestuto, Frank S., Jr.
Partner: UNT Libraries Government Documents Department
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Dislocation Theory of the Fatigue of Metals

Description: "A dislocation theory of fatigue failure for annealed solid solutions is presented. On the basis of this theory, an equation giving the dependence of the number of cycles for failure on the stress, the temperature, the material parameters, and the frequency is derived for uniformly stressed specimens. The equation is in quantitative agreement with the data" (p. 183).
Date: September 12, 1947
Creator: Machlin, E. S.
Partner: UNT Libraries Government Documents Department
open access

Design and performance of family of diffusing scrolls with mixed-flow impeller and vaneless diffuser

Description: A family of diffusing scrolls was designed for use with a mixed-flow impeller and a small-diameter vaneless diffuser. The design theory, intended to maintain a uniform pressure around the scroll inlet, permits determination of the position of scroll cross sections of preassigned area by considering the radial variation in fluid density and the effects of friction along the scroll. Inasmuch as the design method leaves the cross-sectional shape undetermined, the effect of certain variations in sc… more
Date: October 1947
Creator: Brown, W. Byron & Bradshaw, Guy R.
Partner: UNT Libraries Government Documents Department
open access

Flight Investigation on a Fighter-Type Airplane of Factors Which Affect the Loads and Load Distributions on the Vertical Tail Surfaces During Rudder Kicks and Fishtails

Description: "Results are presented of a flight investigation conducted on a fighter-type airplane to determine the factors which affect the loads and load distributions on the vertical tail surfaces in maneuvers. An analysis is made of the data obtained in steady flight, rudder kicks, and fishtail maneuvers. For the rudder kicks, the significant loads were the "deflection load" resulting from an abrupt control deflection and the "dynamic load" consisting of a load corresponding to the new static equilibriu… more
Date: 1947
Creator: Boshar, John
Partner: UNT Libraries Government Documents Department
open access

Spark-Timing Control Based on Correlation of Maximum-Economy Spark Timing, Flame-Front Travel, and Cylinder-Pressure Rise

Description: "An investigation was conducted on a full-scale air-cooled cylinder in order to establish an effective means of maintaining maximum-economy spark timing with varying engine operating conditions. Variable fuel-air-ratio runs were conducted in which relations were determined between the spark travel, and cylinder-pressure rise. An instrument for controlling spark timing was developed that automatically maintained maximum-economy spark timing with varying engine operating conditions" (p. 1).
Date: 1947
Creator: Cook, Harvey A.; Heinicke, Orville H. & Haynie, William H.
Partner: UNT Libraries Government Documents Department
open access

Critical Stress of Thin-Walled Cylinders in Axial Compression

Description: Empirical design curves are presented for the critical stress of thin-wall cylinders loaded in axial compression. These curves are plotted in terms of the nondimensional parameters of small-deflection theory and are compared with theoretical curves derived for the buckling of cylinders with simply supported and clamped edges. An empirical equation is given for the buckling of cylinders having a length-radius ratio greater than about 0.75.
Date: March 20, 1947
Creator: Batdorf, S. B.; Schildcrout, Murry & Stein, Manuel
Partner: UNT Libraries Government Documents Department
open access

A Theory of Unstaggered Airfoil Cascades in Compressible Flow

Description: "By use of the methods of thin airfoil theory, which include effects of compressibility, relations are developed which permit the rapid determination of the pressure distribution over an unstaggered cascade of airfoils of a given profile, and the determination of the profile shape necessary to yield a given pressure distribution for small chord/gap ratios. For incompressible flow the results of the theory are compared with available examples obtained by the more exact method of conformal transf… more
Date: September 1947
Creator: Spurr, Robert A. & Allen, H. Julian
Partner: UNT Libraries Government Documents Department
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Damping in pitch and roll of triangular wings at supersonic speeds

Description: A method is derived for calculating the damping coefficients in pitch and roll for a series of triangular wings and a restricted series of sweptback wings at supersonic speeds. The elementary "supersonic source" solution of the linearized equation of motion is used to find the potential function of a line of doublets, and the flows are obtained by surface distributions of these doublet lines. The damping derivatives for triangular wings are found to be a function of the ratio of the tangent of … more
Date: December 12, 1947
Creator: Brown, Clinton E. & Adams, Mac C.
Partner: UNT Libraries Government Documents Department
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Velocity distributions on two-dimensional wing-duct inlets by conformal mapping

Description: The conformal-mapping method of the Cartesian mapping function is applied to the determination of the velocity distribution on arbitrary two-dimensional duct-inlet shapes such as are used in wing installations. An idealized form of the actual wing-duct inlet is analyzed. The effects of leading edge stagger, inlet-velocity ratio, and section lift coefficients on the velocity distribution are included in the analysis. Numerical examples are given and, in part, compared with experimental data.
Date: April 1, 1947
Creator: Perl, W. & Moses, H. E.
Partner: UNT Libraries Government Documents Department
open access

On Similarity Rules for Transonic Flows

Description: "A method used by Tsien to derive similarity rules for hypersonic flows is utilized to derive Von Karman's similarity rules for transonic flows. At the lower limit of the transonic region of flow the theory yields a formula for the critical stream Mach numbers of a given family of symmetrical profiles. It is further shown that this formula can also be obtained by means of the Prandtl-Glauert small-perturbation method" (p. 83).
Date: December 9, 1947
Creator: Kaplan, Carl
Partner: UNT Libraries Government Documents Department
open access

A General Small-Deflection Theory for Flat Sandwich Plates

Description: "A small-deflection theory is developed for the elastic behavior of orthotropic flat plates in which deflections due to shear are taken into account. In this theory, which covers all types of flat sandwich construction, a plate is characterized by seven physical constants (five stiffnesses and two Poisson ratios) of which six are independent. Both the energy expression and the differential equations are developed. Boundary conditions corresponding to simply supported, clamped, and elastically r… more
Date: September 30, 1947
Creator: Libove, Charles & Batdorf, S. B.
Partner: UNT Libraries Government Documents Department
open access

The interdependence of various types of autoignition and knock

Description: A study of the relations existing among pin-point autoignition, homogeneous autoignition, and knock has been made by means of the NACA high-speed camera and the full-view combustion apparatus. High-speed photographic records of combustion, together with corresponding pressure-time traces, of benzene, 2,2,3-trimethylbutane, S-4, and M-4 fuels at various engine conditions have shown the engine conditions under which each of these phenomena occur and the relation of these phenomena to one another.
Date: February 10, 1947
Creator: Olsen, H. Lowell & Miller, Cearcy D.
Partner: UNT Libraries Government Documents Department
open access

Theoretical motions of hydrofoil systems

Description: "Results are presented of an investigation that has been undertaken to develop theoretical methods of treating the motions of hydrofoil systems and to determine some of the important parameters. Variations of parameters include three distributions of area between the hydrofoils, two rates of change of downwash angle with angle of attack, three depths of immersion, two dihedral angles, two rates of change of lift with immersion, three longitudinal hydrofoil spacings, two radii of gyration in pit… more
Date: May 9, 1947
Creator: Imlay, Frederick H.
Partner: UNT Libraries Government Documents Department
open access

Analysis of Performance of Jet Engine From Characteristics of Components 1: Aerodynamic and Matching Characteristics of Turbine Component Determined With Cold Air

Description: "The performance of the turbine component of an NACA research jet engine was investigated with cold air. The interaction and the matching of the turbine with the NACA eight-stage compressor were computed with the combination considered as a jet engine. The over-all performance of the engine was then determined. The internal aerodynamics were studied to the extent of investigating the performance of the first stator ring and its influence on the turbine performance" (p. 397).
Date: June 6, 1947
Creator: Goldstein, Arthur W.
Partner: UNT Libraries Government Documents Department
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Interference Method for Obtaining the Potential Flow Past an Arbitrary Cascade of Airfoils

Description: "A procedure is presented for obtaining the pressure distribution on an arbitrary airfoil section in cascade in a two-dimensional, incompressible, and nonviscous flow. The method considers directly the influence on a given airfoil of the rest of the cascade and evaluates this interference by an iterative process, which appeared to converge rapidly in the cases tried (about unit solidity, stagger angles of 0 degree and 45 degrees). Two variations of the basic interference calculations are descri… more
Date: January 10, 1947
Creator: Katzoff, S.; Finn, Robert S. & Laurence, James C.
Partner: UNT Libraries Government Documents Department
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Effect of combustor-inlet conditions on performance of an annular turbojet combustor

Description: From Summary: "The combustion performance, and particularly the phenomenon of altitude operational limits, was studied by operating the annular combustor of a turbojet engine over a range of conditions of air flow, inlet pressure, inlet temperature, and fuel flow. Information was obtained on the combustion efficiencies, the effect on combustion of inlet variables, the altitude operational limits with two different fuels, the pressure losses in the combustor, the temperature and velocity profile… more
Date: March 21, 1947
Creator: Childs, J. Howard; McCafferty, Richard J. & Surine, Oakley W.
Partner: UNT Libraries Government Documents Department
open access

Frequency-Response Method for Determination of Dynamic Stability Characteristics of Airplanes With Automatic Controls

Description: "A frequency-response method for determining the critical control-gearing and hunting oscillations of airplanes with automatic pilots is presented. The method is graphical and has several advantages over the standard numerical procedure based on Routh's discriminant. The chief advantage of the method is that direct use can be made of the measured response characteristics of the automatic pilot. This feature is especially useful in determining the existence, amplitude, and frequency of the hunti… more
Date: 1947
Creator: Greenberg, Harry
Partner: UNT Libraries Government Documents Department
open access

Effects of sweepback on boundary layer and separation

Description: "Following a law of stress adopted in the Navier-Stokes equations, the configuration of the viscous flow in planes at right angles to the axis of an infinite cylinder is found to be independent of the axial motion of the cylinder. In the limiting case of a yawed or swept wing of very high aspect ratio, certain boundary-layer and separation phenomena are thus determined independently by the crosswise component of velocity. It follows that the effect of sweepback is to increase the area of stable… more
Date: July 1947
Creator: Jones, Robert T.
Partner: UNT Libraries Government Documents Department
open access

Wing plan forms for high-speed flight

Description: From Summary: "It is pointed out that, in the case of an airfoil of infinite aspect ratio moving at an angle of sideslip, the pressure distribution is determined solely by that component of the motion in a direction normal to the leading edge. It follows that the attachment of plane waves to the airfoil at near-sonic or supersonic speeds (Ackeret theory) may be avoided and the pressure drag may be reduced by the use of plan forms in which the angle of sweepback is greater than the Mach angle."
Date: 1947
Creator: Jones, Robert T.
Partner: UNT Libraries Government Documents Department
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