National Advisory Committee for Aeronautics (NACA) - 327 Matching Results

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Two-dimensional aerodynamic characteristics of 34 miscellaneous airfoil sections

Description: The aerodynamic characteristics of 34 miscellaneous airfoils tested in the Langley two-dimensional low-turbulence tunnels are presented. The data include lift, drag, and in some cases, pitching-moment characteristics, for Reynolds numbers between 3.0 x 10 (exp 6) and 9.0 x 10 (exp 6).
Date: January 31, 1949
Creator: Loftin, Laurence K., Jr. & Smith, Hamilton A.
Partner: UNT Libraries Government Documents Department

Vibration survey of blades in 10-stage axial-flow compressor: 1: static investigation

Description: From Summary: "An investigation was conducted to determine the cause of failures in the seventh- and tenth-stage blades of an axial-flow compressor. The natural frequencies of all rotor blades were measured and critical-speed diagrams were plotted. These data show that the failures were possibly caused by resonance of a first bending-mode vibration excited by a fourth order of the rotor speed in the seventh stage and a sixth order in the tenth stage."
Date: January 31, 1949
Creator: Meyer, André J., Jr. & Calvert, Howard F.
Partner: UNT Libraries Government Documents Department

Performance of Axial-Flow Supersonic Compressor on XJ-55-FF-1 Turbojet Engine 1: Preliminary Performance of Compressor

Description: An investigation was conducted to determine the performance characteristics of the axial-flow supersonic compressor of the XJ-55-FF-1 turbo Jet engine. The test unit consisted of a row of inlet guide vanes and a supersonic rotor; the stator vanes after the rotor were omitted. The maximum pressure ratio produced in the single stage was 2.28 at an equivalent tip speed or 1814 feet per second with an adiabatic efficiency of approximately 0.61, equivalent weight flow of 13.4 pounds per second. The maximum efficiency of 0.79 was obtained at an equivalent tip speed of 801 feet per second.
Date: January 30, 1949
Creator: Hartmann, Melvin J. & Graham, Robert C.
Partner: UNT Libraries Government Documents Department

Experimental pressure distributions over wing tips at Mach number 1.9 I :wing tip with subsonic leading edge

Description: An investigation was conducted at a Mach number of 1.91 to determine spanwise pressure distribution over a wing tip in a region influenced by a sharp subsonic leading edge swept back at 70 degrees. Except for pressure distribution on the top surface in the immediate vicinity of the subsonic leading edge, the maximum difference between linearized theory and experimental data was 2 1/2 percent (of free-stream dynamic pressure) for angles of attack up to 4 degrees and 7 percent for angles of attack up to 8 degrees. Pressures on the top surface nearest the subsonic edge indicated local expansions beyond values predicted by linearized theory.
Date: January 27, 1949
Creator: Jagger, James M. & Mirels, Harold
Partner: UNT Libraries Government Documents Department

Lateral-Control Investigation on a 37 Degree Sweptback Wing of Aspect Ratio 6 at a Reynolds Number of 6,800,000

Description: Memorandum presenting the low-speed lateral-control characteristics of a 37 degree sweptback semispan wing of aspect ratio 6 and NACA 64-series airfoil sections in the 19-foot pressure tunnel. The investigation included the measurement of the hinge-moment characteristics of an aileron and the rolling-effectiveness characteristics of the aileron and two configurations of spoilers.
Date: January 27, 1949
Creator: Graham, Robert R. & Koven, William
Partner: UNT Libraries Government Documents Department

On the flying qualities of helicopters

Description: Report presenting the flying qualities problems of current helicopters, including instability with angle of attack in forward flight, control sensitivity in hovering, and control forces following control movement in maneuvers. Some possible solutions to these issues are presented.
Date: January 27, 1949
Creator: Reeder, John P. & Gustafson, F. B.
Partner: UNT Libraries Government Documents Department

Aerodynamic study of a wing-fuselage combination employing a wing swept back 63 degrees: Characteristics at a Mach number of 1.53 including effect of small variations of sweep

Description: Measured values of lift, drag, and pitching moment at a Mach number of 1.53 and Reynolds numbers of 0.31, 0.62, and 0.84 million are presented for a wing-fuselage combination having a wing leading-edge sweep angle of 63 degrees, an aspect ratio of 3.42, a taper ratio of 0.25, and an NACA 64A006 section in the stream direction. Data are also presented for sweep angles of 57.0 degrees, 60.4 degrees, 67.0 degrees, and 69.9 degrees. The experimentally determined characteristics were less favorable than indicated by the linear theory but the experimental and theoretical trends with sweep were in good agreement. Boundary-layer-flow tests showed that laminar boundary-layer separation was the primary cause of the differences between experiment and theory.
Date: January 26, 1949
Creator: Madden, Robert T.
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation at low speeds of various plug-aileron and lift-flap configurations on a 42 degree sweptback semispan wing

Description: Report presenting a wind-tunnel investigation on a 42 degree sweptback-wing model to determine the lateral control characteristics of a plug-aileron configuration. The configuration consisted of six segments extending from the wing 20-percent-span to the wing 80-percent-span stations and with the center of each plug on the wing 70-percent-chord line. Results regarding wing aerodynamic characteristics and lateral control characteristics are provided.
Date: January 26, 1949
Creator: Schneiter, Leslie E. & Watson, James M.
Partner: UNT Libraries Government Documents Department

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 was found that the rates of spread of the mixing zone both into the jet and into the ambient air were less than those of subsonic jets.
Date: January 21, 1949
Creator: Gooderum, Paul B.; Wood, George P. & Brevoort, Maurice J.
Partner: UNT Libraries Government Documents Department

Performance of 24-inch supersonic axial-flow compressor in air 2: performance of compressor rotor at equivalent tip speeds from 800 to 1765 feet per second

Description: Report presenting an investigation of a 24-inch-diameter rotor for a supersonic axial-flow compressor in air up to an actual tip speed of 1654 feet per second and a maximum equivalent tip speed of 1765 feet per second. Results regarding overall performance, rotor-inlet characteristics, rotor-passage flow characteristics, and rotor-outlet characteristics are provided.
Date: January 21, 1949
Creator: Johnsen, Irving A.; Wright, Linwood C. & Hartmann, Melvin J.
Partner: UNT Libraries Government Documents Department

Response of a Rotating Propeller to Aerodynamic Excitation

Description: The flexural vibration of a rotating propeller blade with clamped shank is analyzed with the object of presenting, in matrix form, equations for the elastic bending moments in forced vibration resulting from aerodynamic forces applied at a fixed multiple of rotational speed. Matrix equations are also derived which define the critical speeds end mode shapes for any excitation order and the relation between critical speed and blade angle. Reference is given to standard works on the numerical solution of matrix equations of the forms derived. The use of a segmented blade as an approximation to a continuous blade provides a simple means for obtaining the matrix solution from the integral equation of equilibrium, so that, in the numerical application of the method presented, the several matrix arrays of the basic physical characteristics of the propeller blade are of simple form, end their simplicity is preserved until, with the solution in sight, numerical manipulations well-known in matrix algebra yield the desired critical speeds and mode shapes frame which the vibration at any operating condition may be synthesized. A close correspondence between the familiar Stodola method and the matrix method is pointed out, indicating that any features of novelty are characteristic not of the analytical procedure but only of the abbreviation, condensation, and efficient organization of the numerical procedure made possible by the use of classical matrix theory.
Date: January 21, 1949
Creator: Arnoldi, Walter E.
Partner: UNT Libraries Government Documents Department

The effect of rate of change of angle of attack on the maximum lift coefficient of a pursuit airplane

Description: Report presenting an investigation of the effect of the rate of change of angle of attack on the maximum lift coefficient of a pursuit airplane equipped with a low-drag-type wing in stalls of varying abruptness over a range of Mach and Reynolds numbers. Maximum lift coefficients were found to increase linearly with increasing rate of change of angle of attack per chord length of travel up to the maximum rate attained in the tests.
Date: January 20, 1949
Creator: Gadeberg, Burnett L.
Partner: UNT Libraries Government Documents Department

Investigation of a thin wing of aspect ratio 4 in the Ames 12-foot pressure wind tunnel 4 : the effect of a constant-chord leading-edge flap at high subsonic speeds

Description: Report presenting wind-tunnel tests of a semispan model of a thin sharp-edged unswept wing of aspect ratio 4 and taper ratio 0.5 equipped with a full-span, constant-chord, leading-edge flap. The effectiveness of the leading-edge flap in improving the lift-drag ratio of the wing was investigated over a range of Mach and Reynolds numbers. Results regarding the lift characteristics, drag characteristics, pitching-moment characteristics, and lift-drag ratio are provided.
Date: January 20, 1949
Creator: Johnson, Ben H., Jr. & Reed, Verlin D.
Partner: UNT Libraries Government Documents Department

Pressure Distributions on Thin Conical Body of Elliptic Cross Section at Mach Number 1.89

Description: Memorandum presenting an investigation conducted to determine the pressure distribution on a conical body of elliptic cross section at a Mach number of 1.89. Experimental data are presented for a range of angles of yaw from -16 to 16 degrees and angles of attack from -10 to 10 degrees. As the angle of flow deflection was increased, the deviation from experiment of the theoretical pressure distribution slightly increased, although agreement was satisfactory over the entire range of calculations.
Date: January 20, 1949
Creator: Maslen, Stephen H.
Partner: UNT Libraries Government Documents Department

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.
Partner: UNT Libraries Government Documents Department

Two-dimensional wind-tunnel investigation of two NACA 6-series airfoils with leading-edge slats

Description: Report presenting an investigation of two NACA 6-series airfoils, the NACA 64(sub)1-212 and NACA 65A109 with leading edge slats and split flaps deflected 60 degrees. Information about optimum slat positions, airfoil section lift characteristics, pitching-moment characteristics, and effect of roughness on the lift characteristics was obtained.
Date: January 19, 1949
Creator: Gottlieb, Stanley M.
Partner: UNT Libraries Government Documents Department

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 these measured structural conditions. In accordance with this method, a study was made of the fundamental mechanism by which aging controlled the short-time creep and rupture properties of solution-treated low-carbon n-155 alloy at 1200 degrees F.
Date: January 18, 1949
Creator: Frey, D. N.; Freeman, J. W. & White, A. E.
Partner: UNT Libraries Government Documents Department

Longitudinal Stability and Control Characteristics of a Semispan Wind-Tunnel Model of the XF7U-1 Airplane and a Comparison with Complete-Model Wind-Tunnel Tests and Semispan-Model Wing-Flow Tests

Description: An investigation was conducted on an 0.08-scale semispan model of the Chance Vought XF7U-1 airplane in the Langley high-speed 7- by 10-foot tunnel in the Mach number range from 0.40 to 0.97. The results are compared with those obtained with an 0.08-scale sting-mounted complete model tested in the same tunnel and with an 0.026-scale semispan model tested by the wing-flow method. The lift-curve slopes obtained for the 0.08-scale semispan model and the 0.026-scale wing-flow model were in good agreement but both were generally lower than the values obtained for the sting model.
Date: January 18, 1949
Creator: Goodson, Kenneth W. & King, Thomas J., Jr.
Partner: UNT Libraries Government Documents Department

Report on Investigation of Developed Turbulence

Description: The recent experiments by Jakob and Erk, on the resistance of flowing water in smooth pipes, which are in good agreement with earlier measurements by Stenton and Pannell, have caused me to change my opinion that the empirical Blasius law (resistance proportional to the 7/4 power of the mean velocity) was applicable up to arbitrarily high Reynolds numbers. According to the new tests the exponent approaches 2 with increasing Reynolds number, where it remains an open question whether or not a specific finite limiting value of the resistance factor lambda is obtained at R = infinity. With the collapse of Blasius' law the requirements which produced the relation that the velocity in the proximity of the wall varied in proportion to the 7th root of the wall distance must also become void. However, it is found that the fundamental assumption that led to this relationship can be generalized so as to furnish a velocity distribution for any empirical resistance law. These fundamental assumptions can be so expressed that for the law of velocity distribution in proximity of the wall as well as for that of friction at the wall, a form can be found in which the pipe diameter no longer occurs, or in other words, that the processes in proximity of a wall are not dependent upon the distance of the opposite wall.
Date: January 18, 1949
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department

Theoretical investigation of the dynamic lateral stability characteristics of Douglas design No. 39C, an early version of the X-3 research airplane

Description: Contains results of calculations made to determine the neutral oscillatory stability boundaries, period and time to damp of the oscillatory mode, and motions following disturbances. The calculations were made for Mach numbers of 0.75 and 2.3 at an attitude of 35,000 feet and for the landing condition at sea level.
Date: January 18, 1949
Creator: Bennett, Charles V.
Partner: UNT Libraries Government Documents Department

High-speed wind-tunnel investigation of a sweptback wing with an added triangular area at the center

Description: Report discussing an investigation of two sweptback wings of different plan form in order to determine the effects of adding a triangular area to the inboard section of a conventional sweptback wing as a way to create a wing with two stages of sweepback. Lift, drag, and pitching-moment characteristics are provided for a range of Mach numbers.
Date: January 14, 1949
Creator: Henry, Beverly Z., Jr.
Partner: UNT Libraries Government Documents Department

The Compressible Flow Past Various Plane Profiles Near Sonic Velocity

Description: In an earlier report UM No.1117 by Gothert,the single-source method was applied to the compressible flow around circles, ellipses, lunes, and around an elongated body of revolution at different Mach numbers and the results compared as far as possible with the calculations by Lamla ad Busemann. Essentially, it was found that with favorable source arrangement the single-source method is in good agreement with the calculations of the same degree of approximation by.Lamla and Busemann. Near sonic velocity the number of steps must be increased considerably in order to sufficiently approximate the adiabatic curve. After exceeding a certain Mach number where local supersonic fields occur already, it was no longer possible, in spite of the substantially increased number of steps, to obtain a systematic solution because the calculation diverged. This result,was interpreted to mean that above this point of divergence the symmetrical type of flow ceases to exist and changes into the unsymmetrical type characterized by compressibility shocks.
Date: January 13, 1949
Creator: Goethert, B. & Kawalki, K. H.
Partner: UNT Libraries Government Documents Department

An investigation of the characteristics of three NACA 1-series nose inlets at subcritical and supercritical Mach numbers

Description: Report presenting an investigation of the characteristics of three representative NACA 1-series nose inlets over a Mach number range extending from 0.4 to 0.925 in the high-speed wind tunnel. Results regarding pressure distribution, drag, and some potential design considerations are provided.
Date: January 13, 1949
Creator: Pendley, Robert E. & Smith, Norman F.
Partner: UNT Libraries Government Documents Department