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Application of a channel design method to high-solidity cascades and tests of an impulse cascade with 90 degrees of turning

Description: From introduction: "A technique for application of the channel design methods of reference 11 to the design of high-solidity cascades with prescribed velocity distributions as a function of arc length along the blade-element profiles is presented herein."
Date: November 30, 1951
Creator: Stanitz, John D. & Sheldrake, Leonard J.
Partner: UNT Libraries Government Documents Department
open access

Axially Symmetric Shapes With Minimum Wave Drag

Description: "The external wave drag of bodies of revolution moving at supersonic speeds can be expressed either in terms of the geometry of the body, or in terms of the body-simulating axial source distribution. For purposes of deriving optimum bodies under various given conditions, it is found that the second of the methods mentioned is the more tractable. By use of a quasi-cylindrical theory, that is, the boundary conditions are applied on the surface of a cylinder rather than on the body itself, the var… more
Date: November 22, 1954
Creator: Heaslet, Max A. & Fuller, Franklyn B.
Partner: UNT Libraries Government Documents Department
open access

The Calculation of Pressure on Slender Airplanes in Subsonic and Supersonic Flow

Description: "Under the assumption that a wing, body, or wing-body combination is slender or flying at near sonic velocity, expressions are given which permit the calculation of pressure in the immediate vicinity of the configuration. The disturbance field, in both subsonic and supersonic flight, is shown to consist of two-dimensional disturbance fields extending laterally and a longitudinal field that depends on the streamwise growth of cross-sectional area. A discussion is also given of couplings, between… more
Date: November 28, 1953
Creator: Heaslet, Max A. & Lomax, Harvard
Partner: UNT Libraries Government Documents Department
open access

Charts for Estimating Performance of High-Performance Helicopters

Description: "Theoretically derived charts showing the profile-drag-thrust ratio are presented for helicopter rotors operating in forward flight and having hinged rectangular blades with a linear twist of 0 degree, 8 degrees, and 16 degrees. The charts, showing the profile-drag characteristics of the rotor for various combinations of pitch angle, ratio of thrust coefficient to solidity, and a parameter representing shaft power input, are presented for tip-speed ratios ranging from 0.05 to 0.50. Also present… more
Date: November 23, 1955
Creator: Gessow, Alfred & Tapscott, Robert J.
Partner: UNT Libraries Government Documents Department
open access

Chordwise and Compressibility Corrections to Slender-Wing Theory

Description: Corrections to slender-wing theory are obtained by assuming a spanwise distribution of loading and determining the chordwise variation which satisfies the appropriate integral equation. Such integral equations are set up in terms of the given vertical induced velocity on the center line or, depending on the type of wing plan form, its average value across the span at a given chord station. The chordwise distribution is then obtained by solving these integral equations. Results are shown for fla… more
Date: November 28, 1952
Creator: Lomax, Harvard & Sluder, Loma
Partner: UNT Libraries Government Documents Department
open access

Cloud-droplet ingestion in engine inlets with inlet velocity ratios of 1.0 and 0.7

Description: From Summary: "The paths of cloud droplets into two engine inlets have been calculated for a wide range of meteorological and flight conditions. The amount of water in droplet form ingested by the inlets and the amount and distribution of water impinging on the inlet walls are obtained from these droplet-trajectory calculations. In both types of inlet, a prolate ellipsoid of revolution represents either part or all of the forebody at the center of an annular inlet to an engine. The configuratio… more
Date: November 2, 1955
Creator: Brun, Rinaldo J.
Partner: UNT Libraries Government Documents Department
open access

A comparison of the experimental subsonic pressure distributions about several bodies of revolution with pressure distributions computed by means of the linearized theory

Description: "An analysis is made of the effects of compressibility on the pressure coefficients about several bodies of revolution by comparing experimentally determined pressure coefficients with corresponding pressure coefficients calculated by the use of the linearized equations of compressible flow. The results show that the theoretical methods predict the subsonic pressure-coefficient changes over the central part of the body but do not predict the pressure-coefficient changes near the nose. Extrapola… more
Date: November 5, 1951
Creator: Matthews, Clarence W.
Partner: UNT Libraries Government Documents Department
open access

Ditching investigations of dynamic models and effects of design parameters on ditching characteristics

Description: From Summary: "Data from ditching investigations conducted at the Langley Aeronautical Laboratory with dynamic scale models of various airplanes are presented in the form of tables. The effects of design parameters on the ditching characteristics of airplanes, based on scale-model investigations and on reports of full-scale ditchings, are discussed. Various ditching aids are also discussed as a means of improving ditching behavior."
Date: November 16, 1956
Creator: Fisher, Lloyd J. & Hoffman, Edward L.
Partner: UNT Libraries Government Documents Department
open access

Drag Minimization for Wings and Bodies in Supersonic Flow

Description: "The minimization of inviscid fluid drag is studied for aerodynamic shapes satisfying the conditions of linearized theory, and subject to imposed constraints on lift, pitching moment, base area, or volume. The problem is transformed to one of determining two-dimensional potential flows satisfying either Laplace's or Poisson's equations with boundary values fixed by the imposed conditions. A general method for determining integral relations between perturbation velocity components is developed. … more
Date: November 29, 1957
Creator: Heaslet, Max A. & Fuller, Franklyn B.
Partner: UNT Libraries Government Documents Department
open access

Effect of chord size on weight and cooling characteristics of air-cooled turbine blades

Description: An analysis has been made to determine the effect of chord size on the weight and cooling characteristics of shell-supported, air-cooled gas-turbine blades. In uncooled turbines with solid blades, the general practice has been to design turbines with high aspect ratio (small blade chord) to achieve substantial turbine weight reduction. With air-cooled blades, this study shows that turbine blade weight is affected to a much smaller degree by the size of the blade chord.
Date: November 13, 1956
Creator: Esgar, Jack B.; Schum, Eugene F. & Curren, Arthur N.
Partner: UNT Libraries Government Documents Department
open access

Generalization of Boundary-Layer Momentum-Integral Equations to Three-Dimensional Flows Including Those of Rotating System

Description: "The Navier-Stokes equations of motion and the equation of continuity are transformed so as to apply to an orthogonal curvilinear coordinate system rotating with a uniform angular velocity about an arbitrary axis in space. A usual simplification of these equations as consistent with the accepted boundary-layer theory and an integration of these equations through the boundary layer result in boundary-layer momentum-integral equations for three-dimensional flows that are applicable to either rota… more
Date: November 1, 1950
Creator: Mager, Artur
Partner: UNT Libraries Government Documents Department
open access

Investigation of separated flows in supersonic and subsonic streams with emphasis on the effect of transition

Description: Report presents the results of experimental and theoretical research conducted on flow separation associated with steps, bases, compression corners, curved surfaces, shock-wave boundary-layer reflections, and configurations producing leading-edge separation. Results were obtained from pressure-distribution measurements, shadowgraph observations, high-speed motion pictures, and oil-film studies. The maximum scope of measurement encompassed Mach numbers between 0.4 and 3.6, and length Reynolds nu… more
Date: November 29, 1956
Creator: Chapman, Dean R.; Kuehn, Donald M. & Larson, Howard K.
Partner: UNT Libraries Government Documents Department
open access

Method for calculating lift distributions for unswept wings with flaps or ailerons by use of nonlinear section lift data

Description: A method is presented which allows the use of nonlinear section lift data in the calculation of the spanwise lift distribution of unswept wings with flaps or ailerons. This method is based upon lifting line theory and is an extension to the method described in NACA rep. 865. The mathematical treatment of the discontinuity in absolute angle of attack at the end of the flap or aileron involves the use of a correction factor which accounts for the inability of a limited trigonometric series to rep… more
Date: November 13, 1950
Creator: Sivells, James C. & Westrick, Gertrude C.
Partner: UNT Libraries Government Documents Department
open access

Methods for obtaining desired helicopter stability characteristics and procedures for stability predictions

Description: Part I of this report presents a brief review of methods available to the helicopter designer for obtaining desired stability characteristics by modifications to the airframe design. The discussion is based on modifications made during the establishment of flying-qualities criteria and includes sample results of theoretical studies of additional methods. The conclusion is reached that it is now feasible to utilize combinations of methods whereby stability-parameter values are realized which in … more
Date: November 30, 1956
Creator: Gustafson, F. B. & Tapscott, Robert J.
Partner: UNT Libraries Government Documents Department
open access

Performance and Boundary-Layer Data From 12 Degree and 23 Degree Conical Diffusers of Area Ratio 2.0 at Mach Numbers Up to Choking and Reynolds Numbers Up to 7.5 X 10(6)

Description: "For each of two inlet-boundary-layer thicknesses, performance and boundary-layer characteristics have been determined for a 12 degree, 10-inch-inlet-diameter diffuser, a 12 degree, 21-inch-inlet-diameter diffuser, and a 23 degree, 21-inch-inlet-diameter diffuser. The investigation covered an inlet Mach number range from about 0.10 to coking. The corresponding inlet Reynolds number, based on inlet diameter, varied from about 0.5 x 10(6) to 7.5 x 10(6)" (p. 1013).
Date: November 15, 1954
Creator: Little, B. H., Jr. & Wilbur, Stafford W.
Partner: UNT Libraries Government Documents Department
open access

The response of an airplane to random atmospheric disturbances

Description: The statistical approach to the gust-load problem, which consists in considering flight through turbulent air to be a stationary random process, is extended by including the effect of lateral variation of the instantaneous gust intensity on the aerodynamic forces. The forces obtained in this manner are used in dynamic analyses of rigid and flexible airplanes free to move vertically, in pitch, and in roll. The effect of the interaction of longitudinal, normal, and lateral gusts on the wind stres… more
Date: November 5, 1956
Creator: Diederich, Franklin W.
Partner: UNT Libraries Government Documents Department
open access

Review of experimental investigations of liquid-metal heat transfer

Description: Experimental data of various investigators of liquid-metal heat-transfer characteristics were reevaluated using as consistent assumptions and methods as possible and then compared with each other and with theoretical results. The reevaluated data for both local fully developed and average Nusselt numbers in the turbulent flow region were found still to have considerable spread, with the bulk of the data being lower than predicted by existing analysis. An equation based on empirical grounds whic… more
Date: November 4, 1954
Creator: Lubarsky, Bernard & Kaufman, Samuel J.
Partner: UNT Libraries Government Documents Department
open access

Some Effects of Bluntness on Boundary-Layer Transition and Heat Transfer at Supersonic Speeds

Description: "Large downstream movements of transition observed when the leading edge of a hollow cylinder or a flat plate is slightly blunted are explained in terms of the reduction in Reynolds number at the outer edge of the boundary layer due to the detached shock wave. The magnitude of this reduction is computed for cones and wedges for Mach numbers to 20. Concurrent changes in outer-edge Mach number and temperature occur in the direction that would increase the stability of the laminar boundary layer. … more
Date: November 21, 1955
Creator: Moeckel, W. E.
Partner: UNT Libraries Government Documents Department
open access

Some effects of frequency on the contribution of a vertical tail to the free aerodynamic damping of a model oscillating in yaw

Description: The damping in yaw and the directional stability of a model freely oscillating in yaw were measured tail-off and tail-on and compared with the values obtained by theoretical consideration of the unsteady lift associated with an oscillating vertical tail. A range of low frequencies comparable to those of the lateral motions of airplanes was covered. The analysis includes the effects of vertical-tail aspect ratio and the two-dimensional effects of compressibility.
Date: November 26, 1951
Creator: Bird, John D.; Fisher, Lewis R. & Hubbard, Sadie M.
Partner: UNT Libraries Government Documents Department
open access

Study of inadvertent speed increases in transport operation

Description: From Summary: "Some factors relating to inadvertent speed and Mach number increases in transport operation are discussed with the object of indicating the manner in which they might vary with different qualities of the airplane and the minimum margins required to guard against reaching unsafe values. The speed increments and the margins required under several assumed conditions are investigated. The results indicate that, on a percentage basis, smaller margins should be required of high-speed a… more
Date: November 16, 1951
Creator: Pearson, Henry A.
Partner: UNT Libraries Government Documents Department
open access

A theoretical and experimental study of planing surfaces including effects of cross section and plan form

Description: A summary is given of the background and present status of the pure-planing theory for rectangular flat plates and v-bottom surfaces. The equations reviewed are compared with experiment. In order to extend the range of available planing data, the principal planing characteristics for models having sharp bottom surfaces having constant angles of dead rise of 20 degrees and 40 degrees. Planing data were also obtained for flat-plate surfaces with very slightly rounded chines for which decreased li… more
Date: November 23, 1956
Creator: Shuford, Charles L., Jr.
Partner: UNT Libraries Government Documents Department
open access

Theoretical Prediction of Pressure Distributions on Nonlifting Airfoils at High Subsonic Speeds

Description: "Theoretical pressure distributions on nonlifting circular-arc airfoils in two-dimensional flows with high subsonic free-stream velocity are found by determining approximate solutions, through an iteration process, of an integral equation for transonic flow proposed by Oswatitsch. The integral equation stems directly from the small-disturbance theory for transonic flow. This method of analysis possesses the advantage of remaining in the physical, rather than the hodograph, variable and can be a… more
Date: November 19, 1953
Creator: Spreiter, John R. & Alksne, Alberta
Partner: UNT Libraries Government Documents Department
open access

Wind-tunnel investigation at low speed of the effects of chordwise wing fences and horizontal-tail position on the static longitudinal stability characteristics of an airplane model with a 35 degree sweptback wing

Description: From Summary: "Low-speed tests of a model with a wing swept back 35 degrees at the 0.33-chord line and a horizontal tail located well above the extended wing-chord plane indicated static longitudinal instability at moderate angles of attack for all configurations tested. An investigation therefore was made to determine whether the longitudinal stability could be improved by the use of chordwise wing fences, by lowering the horizontal tail, or by a combination of both."
Date: November 24, 1954
Creator: Queijo, M. J.; Jaquet, Byron M. & Wolhart, Walter D.
Partner: UNT Libraries Government Documents Department
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