National Advisory Committee for Aeronautics (NACA) - 509 Matching Results

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A simplified method for the determination and analysis of the neutral-lateral-oscillatory-stability boundary

Description: A necessary condition for neutral oscillatory stability is that Routh's discriminant r, formed from the coefficients of the stability equation, is equal to zero. Computations obtained from rsub1=0 and d=0 show very good agreement with the results calculated by the expression for r=0. The nature of the modes of motion as a function of the directional-stability derivative and the effective-dihedral derivative is discussed in detail.
Date: 1949
Creator: Sternfield, Leonard & Gates, Ordway B., Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Heat transfer to bodies traveling at high speed in the upper atmosphere

Description: 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
Item Type: Refine your search to only Report
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: A low-scale wind-tunnel investigation was conducted in rolling flow to determine the effects of aspect ratio and sweep (when varied independently) on the rolling stability derivatives for a series of untapered wings. The rolling-flow equipment of the Langley stability tunnel was used for the tests. The data of the investigation have been used to develop a method of accounting for the effects of the drag on the yawing moment due to rolling throughout the lift range.
Date: January 19, 1949
Creator: Goodman, Alex & Fisher, Lewis R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The effect of torsional flexibility on the rolling characteristics at supersonic speeds of tapered unswept wings

Description: 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 ai… more
Date: March 8, 1949
Creator: Tucker, Warren A. & Nelson, Robert L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Attainable Circulation About Airfoils in Cascade

Description: "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 loadi… more
Date: September 1949
Creator: Goldstein, Arthur W. & Mager, Artur
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Two-dimensional compressible flow in centrifugal compressors with straight blades

Description: "Six numerical examples are presented for steady, two-dimensional, compressible, nonviscous flow in centrifugal compressors with thin straight blades, the center lines of which generate the surface of a right circular cone when rotated about the axis of the compressor. A seventh example is presented for incompressible flow. The solutions were obtained in a region of the compressors, including the impeller tip, that was considered to be unaffected by the diffuser vanes or by the impeller-inlet c… more
Date: June 21, 1949
Creator: Stanitz, John D. & Ellis, Gaylord O.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Application of Radial-Equilibrium Condition to Axial-Flow Compressor and Turbine Design

Description: "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 … more
Date: January 1, 1949
Creator: Wu, Chung-Hua & Wolfenstein, Lincoln
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Laminar mixing of a compressible fluid

Description: From Summary: "A theoretical investigation of the velocity profiles for laminar mixing of a high-velocity stream with a region of fluid at rest has been made assuming that the Prandtl number is unity. A method which involves only quadratures is presented for calculating the velocity profile in the mixing layer for an arbitrary value of the free-stream Mach number. Detailed velocity profiles have been calculated for free-stream Mach numbers of 0, 1, 2, 3, and 5."
Date: January 5, 1949
Creator: Chapman, Dean R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Investigation with an interferometer of the turbulent mixing of a free supersonic jet

Description: The free turbulent mixing of a supersonic jet of Mach number 1.6 has been experimentally investigated. An interferometer, of which a description is given, was used for the investigation. Density and velocity distributions through the mixing zone have been obtained. It was found that there was similarity in distribution at the cross sections investigated and that, in the subsonic portion of the mixing zone, the velocity distribution fitted the theoretical distribution for incompressible flow. It… more
Date: January 21, 1949
Creator: Gooderum, Paul B.; Wood, George P. & Brevoort, Maurice J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Characteristics of Low-Aspect-Ratio Wings at Supercritical Mach Numbers

Description: "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 effe… more
Date: 1949
Creator: Stack, John & Lindsey, W. F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effect of Reynolds Number in Turbulent-Flow Range on Flame Speeds of Bunsen Burner Flames

Description: "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 i… more
Date: 1949
Creator: Bollinger, Lowell M. & Williams, David T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Recommendations for Numerical Solution of Reinforced-Panel and Fuselage-Ring Problems

Description: "Procedures are recommended for solving the equations of equilibrium of reinforced panels and isolated fuselage rings as represented by the external loads and the operations table established according to Southwell's method. From the solution of these equations the stress distribution can be easily determined. The method of systematic relaxations, the matrix-calculus method, and several other methods applicable in special cases are discussed" (p. 1).
Date: 1949
Creator: Hoff, N. J. & Libby, Paul A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Two-Dimensional Compressible Flow in Turbomachines With Conic Flow Surfaces

Description: "A general method of analysis is developed for two-dimensional, steady, compressible flow in stators or rotors of radial and mixed flow turbomachines with conic flow surfaces (surfaces of right circular cones generated by center line of flow passage in the axial-radial plane). The variables taken into account are: (1) tip speed of the rotor, (2) flow rate, (3) blade shape, (4) variation in passage height with radius, (5) number of blades, and (6) cone angle of the flow surface. Relaxation metho… more
Date: 1949
Creator: Stanitz, John D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The effect of blade-section thickness ratio on the aerodynamic characteristics of related full-scale propellers at Mach numbers up to 0.65

Description: 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
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Investigation of Separation of the Turbulent Boundary Layer

Description: "An investigation was conducted on a turbulent boundary layer near a smooth surface with pressure gradients sufficient to cause flow separation. The Reynolds number was high, but the speeds were entirely within the incompressible flow range. The investigation consisted of measurements of mean flow, three components of turbulence intensity, turbulent shearing stress, and correlations between two fluctuation components at a point and between the same component of different points" (p. 1).
Date: June 1, 1949
Creator: Schubauer, G. B. & Klebanoff, P. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Spectra and diffusion in a round turbulent jet

Description: "In a round turbulent jet at room temperature, measurement of the shear correlation coefficient as a function of frequency (through band-pass filters) has given a rather direct verification of Kolmogoroff's local-isotropy hypothesis. One-dimensional power spectra of velocity and temperature fluctuations, measured in unheated and heated jets, respectively, have been contrasted. Under the same conditions, the two corresponding transverse correlation functions have been measured and compared" (p. … more
Date: August 17, 1949
Creator: Corrsin, Stanley & Uberoi, Mahinder S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Influence of chemical composition on rupture properties at 1200 degrees F of forged chromium-cobalt-nickel-iron base alloys in solution-treated and aged condition

Description: From Summary: "The influence of systematic variations of chemical composition on rupture properties at 1200 degrees F. was determined for 62 modifications of a basic alloy containing 20 percent chromium, 20 percent nickel, 20 percent cobalt, 3 percent molybdenum, 2 percent tungsten, 1 percent columbium, 0.15 percent carbon, 1.7 percent manganese, 0.5 percent silicon, 0.12 percent nitrogen and the balance iron. These modifications included individual variations of each of 10 elements present and… more
Date: October 26, 1949
Creator: Reynolds, E. E.; Freeman, J. W. & White, A. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Theoretical antisymmetric span loading for wings of arbitrary plan form at subsonic speeds

Description: A simplified lifting-surface theory that includes effects of compressibility and spanwise variation of section lift-curve slope is used to provide charts with which antisymmetric loading due to arbitrary antisymmetric angle of attack can be found for wings having symmetric plan forms with a constant spanwise sweep angle of the quarter-chord line. Consideration is given to the flexible wing in roll. Aerodynamic characteristics due to rolling, deflected ailerons, and sideslip of wings with dihedr… more
Date: December 22, 1949
Creator: DeYoung, John
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Investigation of Fretting by Microscopic Observation

Description: "An experimental investigation, using microscopic observation and color motion photomicrographs of the action, was conducted to determine the cause of fretting. Glass and other noncorrosive materials, as well as metals, were used as specimens. A very simple apparatus vibrated convex surfaces in contact with stationary flat surfaces at frequencies of 120 cycles or less than l cycle per second, an amplitude of 0.0001 inch, and load of 0.2 pound" (p. 135).
Date: August 31, 1949
Creator: Godfrey, Douglas
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Dynamics of a turbojet engine considered as a quasi-static system

Description: 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 … more
Date: July 27, 1949
Creator: Otto, Edward W. & Taylor, Burt L., III
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effects of wing flexibility and variable air lift upon wing bending moment during landing impacts of a small seaplane

Description: 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 w… more
Date: December 21, 1949
Creator: Merten, Kenneth F. & Beck, Edgar B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effect of tunnel configuration and testing technique on cascade performance

Description: "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 aspe… more
Date: November 30, 1949
Creator: Erwin, John R. & Emery, James C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A theoretical analysis of the effect of time lag in an automatic stabilization system on the lateral oscillatory stability of an airplane

Description: "A method is presented for determining the effect of time lag in an automatic stabilization system on the lateral oscillatory stability of an airplane. The method is based on an analytical-graphical procedure. The critical time lag of the airplane-autopilot system is readily determined from the frequency-response analysis. The method is applied to a typical present-day airplane equipped with an automatic pilot sensitive to yawing acceleration and geared to the rudder so that rudder control is a… more
Date: October 28, 1949
Creator: Sternfield, Leonard & Gates, Ordway B., Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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