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Two-dimensional subsonic compressible flows past arbitrary bodies by the variational method

Description: Instead of solving the nonlinear differential equation which governs the compressible flow, an approximate method of solution by means of the variational method is used. The general problem of steady irrotational flow past an arbitrary body is formulated. Two examples were carried out, namely, the flow past a circular cylinder and the flow past a thin curved surface. The variational method yields results of velocity and pressure distributions which compare excellently with those found by existi… more
Date: March 1951
Creator: Wang, Chi-Teh
Partner: UNT Libraries Government Documents Department
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A flight investigation to increase the safety of a light airplane

Description: Report presenting information about a series of modifications incorporated into light airplanes to increase safety, including decreasing the wing incidence, increasing the wing washout, increasing the area and aspect ratio of the horizontal and vertical tails, moving the elevators out of propeller slipstreams, depressing the thrust axis, and limiting the rudder travel. The new inherent safety characteristics and effects on the airplane's performance are provided.
Date: March 1947
Creator: Hunter, P. A. & Vensel, J. R.
Partner: UNT Libraries Government Documents Department
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Compressive Buckling of Simply Supported Plates With Longitudinal Stiffeners

Description: "Charts are presented for the analysis of the stability under compression of simply supported rectangular plates with one, two, three, and an infinite number of identical equally spaced longitudinal stiffeners that have zero torsional stiffness" (p. 1).
Date: March 1949
Creator: Seide, Paul & Stein, Manuel
Partner: UNT Libraries Government Documents Department
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Linear theory of boundary effects in open wind tunnels with finite jet lengths

Description: Report in two parts: one examines the boundary conditions for an open wind tunnel with special references to the effects of the closed entrance and exit sections, while the other derives solutions of four types of two-dimensional open tunnels, including one in which the pressures on the two free surfaces are not equal.
Date: March 1949
Creator: Katzoff, Samuel; Gardner, Clifford S.; Diesendruck, Leo & Eisenstadt, Bertram J.
Partner: UNT Libraries Government Documents Department
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Matrix Methods for Calculating Cantilever-Beam Deflections

Description: Note presenting the method of numerical integration for calculation of beam deflection in matrix form to give it the advantages which are inherent in an influence-coefficient method. Examples are presented to show that the use of weighted matrices reduces the calculation time required to obtain a desired degree of accuracy.
Date: March 1949
Creator: Benscoter, Stanley U. & Gossard, Myron L.
Partner: UNT Libraries Government Documents Department
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Data on Optimum Length, Shear Strength, and Tensile Strength of Age-Hardened 17S-T Machine-Countersunk Rivets in 75S-T Sheet

Description: Report presenting a series of tensile-strength and shear-strength tests made on age-hardened 17S-T rivets machine-countersunk in 75S-T sheets. The results of the tests indicated that the joints can be made satisfactorily with regard to both flushness and strength if the ratio of buck to diameter is kept to a certain value.
Date: March 1947
Creator: Schuette, Evan H. & Niles, Donald E.
Partner: UNT Libraries Government Documents Department
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The streamline pattern in the vicinity of an oblique airfoil

Description: "A method for determining the streamwise flow pattern of a nonviscous incompressible fluid about an oblique airfoil from the corresponding flow pattern about the airfoil in normal position is presented and illustrated in two examples. The method can be extended to account approximately for compressibility effects by applying the Prandtl-Glauert correction factor to the flow pattern that is normal to the leading edge of the airfoil. The method is expected to be useful in determining the shape of… more
Date: March 1947
Creator: Watkins, Charles E.
Partner: UNT Libraries Government Documents Department
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Effect of forebody warp on the hydrodynamic qualities of a hypothetical flying boat having a hull length-beam ratio of 15

Description: Report of an investigation of the effect of forebody warp on the hydrodynamic qualities of a hypothetical flying boat with a hull length-beam ratio of 15 in smooth water and in waves. Warping the forebody planing bottom was found to appreciably increase the range of stable trim between the lower and upper trim limits of stability, although the center-of-gravity limits of stability were reduced.
Date: March 1949
Creator: Carter, Arthur W. & Weinstein, Irving
Partner: UNT Libraries Government Documents Department
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Data on the Compressive Strength of 75S-T6 Aluminum-Alloy Flat Panels with Longitudinal Extruded Z-Section Stiffeners

Description: "The experimental results are presented for a part of an investigation of the compressive strength of 75S-T6 aluminum-alloy flat panels with longitudinal extruded Z-section stiffeners. This part of the investigation is concerned with panels in which the ratio of the thickness of the stiffener material to the skin material varies from 0.4 to 1.0 and the ratio of stiffener spacing to skin thickness varies from 15 to 40" (p. 1).
Date: March 1949
Creator: Hickman, William A. & Dow, Norris F.
Partner: UNT Libraries Government Documents Department
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Experimental Investigation of the Stress Distribution Around Reinforced Circular Cut-Outs in Skin Stringer Panels Under Axial Loads

Description: Note presenting results of strain surveys around four reinforced circular cut-outs successively made in an axially loaded skin-stringer tension panel. Curves are presented which show the distribution of stringer and shear stresses in the panel and bending stresses in the reinforcing rings.
Date: March 1947
Creator: Farb, Daniel
Partner: UNT Libraries Government Documents Department
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Frequency-Response Method for Determination of Dynamic Stability Characteristics of Airplanes With Automatic Controls

Description: Note presenting a frequency-response method for determining the critical control-gearing and hunting oscillations of airplanes with automatic pilots. The method is graphical and has several advantages over the standard numerical procedure based on Routh's discriminant. Several examples are worked out to illustrate the application of the frequency-response method in determining the effect of automatic-pilot lag or lead on critical control gearing and in determining the amplitude and frequency of… more
Date: March 1947
Creator: Greenberg, Harry
Partner: UNT Libraries Government Documents Department
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Effect of Automatic Stabilization on the Lateral Oscillatory Stability of a Hypothetical Airplane at Supersonic Speeds

Description: Note presenting an investigation to determine the effect of automatic stabilization on the lateral oscillatory stability of a hypothetical supersonic airplane. The investigation included an autopilot sensitive to either the yawing or rolling angular velocity. The results of the investigation indicated that all the automatic pilots improved the stability of the original unstable short-period oscillation.
Date: March 1949
Creator: Sternfield, Leonard
Partner: UNT Libraries Government Documents Department
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Notes on the Foundations of the Theory of Small Displacements of Orthotropic Shells

Description: Note presenting a survey that has been made of the various systems of equations which have been given in the literature for the analysis of small deflections of thin elastic shell. A new system of equations has been derived for the analysis of shells, which includes the effects of transverse shear and normal stresses.
Date: March 1949
Creator: Hildebrand, F. B.; Reissner, E. & Thomas, G. B.
Partner: UNT Libraries Government Documents Department
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Flutter of a uniform wing with an arbitrarily placed mass according to a differential-equation analysis and a comparison with experiment

Description: Report presenting a method for the calculation of flutter speed of a uniform wing carrying an arbitrarily placed concentrated mass. The method involves the solution of the differential equations of motion of the wing at flutter speed and does not require the assumption of specific normal modes of vibration.
Date: March 1949
Creator: Runyan, Harry L. & Watkins, Charles E.
Partner: UNT Libraries Government Documents Department
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The influence of blade-width distribution on propeller characteristics

Description: Report presenting combined force and wake survey tests on three-blade model propellers in order to determine the effects of blade-width distribution on constant-speed efficiency characteristics. The most important result is the demonstration that blade-width distribution has a marked influence on the constant-speed efficiency characteristics of propellers.
Date: March 1949
Creator: Reid, Elliott G.
Partner: UNT Libraries Government Documents Department
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Preliminary Analysis of NACA Measurements of Atmospheric Turbulence Within a Thunderstorm - U.S. Weather Bureau Thunderstorm Project

Description: "A general description of the field operations of the U.S. Weather Bureau thunderstorm project conducted in the vicinity of Orlando, Florida during the summer month of 1946 is given. The participation of NACA in this project is described and measurements of atmospheric turbulence taken by NACA are presented for one of the flights. The results indicate that some regions of thunderstorms may present no great hazard to flight, while exceptionally severe conditions of atmospheric turbulence may occ… more
Date: March 1947
Creator: Tolefson, Harold B.
Partner: UNT Libraries Government Documents Department
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Investigation at low speeds of the effect of aspect ratio and sweep on rolling stability derivatives of untapered wings

Description: Report presenting a wind-tunnel investigation conducted in rolling flow to determine the effects of aspect ratio and sweep on the rolling stability derivatives for a series of untapered wings. The results indicated that when the aspect ratio is held constant, an increase in sweepback angle causes a significant reduction in the damping in roll at low lift coefficients for only the higher aspect ratios tested.
Date: March 1949
Creator: Goodman, Alex & Fisher, Lewis R.
Partner: UNT Libraries Government Documents Department
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Strength analysis of stiffened thick beam webs

Description: Report presenting a method for the strength analysis of stiffened beam webs as applied to beams with ratios of applied shear to buckling shear less than 2.5. Results regarding critical shear stress, forced crippling failure in uprights, and web failures are provided.
Date: March 1949
Creator: Levin, L. Ross & Sandlin, Charles W., Jr.
Partner: UNT Libraries Government Documents Department
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Ambient Pressure Determination at High Altitudes by Use of Free-Molecule Theory

Description: "Several methods (references 1 and 2) based on gas-dynamic principles are available for reducing such measurements. The results obtained by these methods are subject to the limitation of the gas-dynamic theory which is that the mean free path of the molecules between impacts, is small with respect to the measuring device. Inasmuch as no information on the subject is to present known to be available, the purpose of the present paper is to present a method based on the concept of free-molecule th… more
Date: March 1949
Creator: Wiener, Bernard
Partner: UNT Libraries Government Documents Department
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Dynamometer-stand investigation of a group of mufflers

Description: Report presenting an experimental investigation of a series of exhaust mufflers installed on a typical six-cylinder light-airplane engine mounted on a ground dynamometer sound. Several conclusions regarding muffler design are drawn from this testing. Since engine and propeller noise are about equal for this power-plant installation, both engine-exhaust and propeller noises must be reduced to obtain a sizable reduction in overall sound-pressure level.
Date: March 1949
Creator: Davis, Don D., Jr. & Czarnecki, K. R.
Partner: UNT Libraries Government Documents Department
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Effect of heat and power extraction on turbojet-engine performance 1: analytical method of performance evaluation with compressor-outlet air bleed

Description: Report presenting an analytical investigation of the performance of a turbojet engine with air bled off at the compressor outlet. A wide range of engine and flight conditions are covered and air bleeds of 0 to 15 percent of the air mass flow are considered. Results are provided in the form of generalized performance charts that are applicable to a wide range of operating conditions.
Date: March 1950
Creator: Hensley, Reece V.; Rom, Frank E. & Koutz, Stanley L.
Partner: UNT Libraries Government Documents Department
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Tables of wing-aileron coefficients of oscillating air forces for two-dimensional supersonic flow

Description: Report presenting the wing-aileron coefficients of oscillating air forces for two-dimensional supersonic flow for a variety of Mach numbers. Various ratios of control-surface chord to airfoil chord are employed in the calculation and for each combination of chord ratio and Mach number, approximate 35 values of reduced frequency are utilized.
Date: March 1950
Creator: Huckel, Vera & Durling, Barbara J.
Partner: UNT Libraries Government Documents Department
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Velocity Distribution on Wing Sections of Arbitrary Shape in Compressible Potential Flow 3: Circulatory Flows Obeying the Simplified Density-Speed Relation

Description: "The method of computing velocity and pressure distributions along wing profiles under the assumption of the simplified density-speed relation, outlined in NACA Technical Note 1006, is extended to the case of a nonsymmetrical profile and a flow with circulation. The shape of the profile, the speed of the undisturbed flow, and a parameter determining the angle of attack may be prescribed. The problem is reduced to a nonlinear integral equation which can be solved numerically by an iteration meth… more
Date: March 1950
Creator: Bers, Lipman
Partner: UNT Libraries Government Documents Department
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A method of computing subsonic flows around given airfoils

Description: From Summary: "An extremely simple computational method is established for obtaining circulatory flows around given bodies to a high degree of accuracy for flows satisfying the linear pressure and specific-volume equation of state. The method depends not on an integral equation but on the transformation from the holograph to the physical plane involving the determination of an arbitrary analytic function. The determination of the arbitrary analytic function by elementary means results in a clos… more
Date: March 1950
Creator: Gelbart, Abe & Resch, Daniel
Partner: UNT Libraries Government Documents Department
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