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

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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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Frequency Response of Linear Systems From Transient Data

Description: "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… more
Date: April 1, 1949
Creator: LaVerne, Melvin E. & Boksenbom, Aaron S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Method of designing cascade blades with prescribed velocity distributions in compressible potential flows

Description: By use of the assumption that the pressure-volume relation is linear, a solution to the problem of designing a cascade for a given turning and with a prescribed velocity distribution along the blade in a potential flow of a compressible perfect fluid was obtained by a method of correspondence between potential flows of compressible and incompressible fluids. The designing of an isolated airfoil with a prescribed velocity distribution along the airfoil is considered as a special case of cascade.… more
Date: October 1, 1949
Creator: Costello, George R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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On Stability of Free Laminar Boundary Layer Between Parallel Streams

Description: "An analysis and calculations on the stability of the free laminar boundary layer between parallel streams were made for an incompressible fluid using the Tollmien-Schlichting theory of small disturbances. Because the boundary conditions are at infinity, two solutions of the Orr-Sommerfeld stability equations need not be considered, and the remaining two solutions are exponential in character at the infinite boundaries. The calculations show that the flow is unstable except for very low Reynold… more
Date: March 21, 1949
Creator: Lessen, Martin
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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General algebraic method applied to control analysis of complex engine types

Description: "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 … more
Date: April 25, 1949
Creator: Boksenbom, Aaron S. & Hood, Richard
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Theoretical analysis of various thrust-augmentation cycles for turbojet engines

Description: "The results of analytical studies of tail-pipe-burning, water-injection, and bleedoff methods of thrust augmentation are presented that provide an insight into the operating characteristics of these augmentation methods and summarizes the performance that may be obtained when applied to a typical turbojet engine. A brief description of the principles of operation of each augmentation method is given, together with curves that illustrate the effects of the principal design and operating variabl… more
Date: September 2, 1949
Creator: Lundin, Bruce T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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An introduction to the physical aspects of helicopter stability

Description: In order to provide engineers interested in rotating-wing aircraft, but with no specialized training in stability theory, some understanding of the factors that influence the flying qualities of the helicopter, an explanation is made of both the static stability and the stick-fixed oscillation in hovering and forward flight in terms of fundamental physical quantities. Three significant stability factors -- static stability with angle of attack, static stability with speed, and damping due to a … more
Date: September 19, 1949
Creator: Gessow, Alfred & Amer, Kenneth B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Fundamental effects of aging on creep properties of solution-treated low-carbon N-155 alloy

Description: 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 thes… more
Date: January 18, 1949
Creator: Frey, D. N.; Freeman, J. W. & White, A. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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