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Intensity, scale, and spectra of turbulence in mixing region of free subsonic jet

Description: Report presents the results of the measurements of intensity of turbulence, the longitudinal and lateral correlation coefficients, and the spectra of turbulence in a 3.5-inch-diameter free jet measured with hot-wire anemometers at exit Mach numbers from 0.2 to 0.7 and Reynolds numbers from 192,000 to 725,000.
Date: April 24, 1956
Creator: Laurence, James C.
Partner: UNT Libraries Government Documents Department
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Requirements for Satisfactory Flying Qualities of Airplanes

Description: Report discusses the results of an analysis of available data to determine what measured characteristics are significant in defining satisfactory flying qualities, what characteristics are reasonable to require of an airplane, and what influence the various design features have on the observed flying qualities.
Date: March 24, 1941
Creator: Gilruth, R. R.
Partner: UNT Libraries Government Documents Department
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Application of Spring Tabs to Elevator Controls

Description: Equations are presented for calculating the stick-force characteristics obtained with a spring-tab type of elevator control. The main problems encountered in the design of a satisfactory elevator spring tab are to provide stick forces in the desired range, to maintain the force per g sufficiently constant throughout the speed range, to avoid undesirable "feel" of the control in ground handling or in flight at low airspeeds, and to prevent flutter. Examples are presented to show the design featu… more
Date: November 24, 1944
Creator: Phillips, William H.
Partner: UNT Libraries Government Documents Department
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Square Plate With Clamped Edges Under Normal Pressure Producing Large Deflections

Description: "A theoretical analysis is given for the stresses and deflections of a square plate with clamped edges under normal pressure producing large deflections. Values of the bending stress and membrane stress at the center of the plate and at the midpoint of the edge are given for center deflections up to 1.9 times the plate thickness. The shape of the deflected surface is given for low pressures and for the highest pressure considered" (p. 209).
Date: May 24, 1941
Creator: Levy, Samuel
Partner: UNT Libraries Government Documents Department
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An apparatus for varying effective dihedral in flight with application to a study of tolerable dihedral on a conventional fighter airplane

Description: From Summary: "An apparatus for varying effective dihedral in flight by means of servo actuation of the ailerons in response to sideslip angle is described. The results of brief flight tests of the apparatus on a conventional fighter airplane are presented and discussed. The results of an investigation employing the apparatus to determine the tolerable (safe for normal fighter operation) range of effective dihedral on the test airplane are presented."
Date: August 24, 1949
Creator: Kauffman, William M.; Liddell, Charles J., Jr.; Smith, Allan & Van Dyke, Rudolph D., Jr.
Partner: UNT Libraries Government Documents Department
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The Linearized Characteristics Method and Its Application to Practical Nonlinear Supersonic Problems

Description: "The methods of characteristics has been linearized by assuming that the flow field can be represented as a basic flow field determined by nonlinearized methods and a linearized superposed flow field that accounts for small changes of boundary conditions. The method has been applied to two-dimensional rotational flow where the basic flow is potential flow and to axially symmetric problems where conical flows have been used as the basic flows. In both cases the method allows the determination of… more
Date: July 24, 1951
Creator: Ferri, Antonio
Partner: UNT Libraries Government Documents Department
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Analysis of the effects of wing interference on the tail contributions to the rolling derivatives

Description: From Introduction: "This report presents calculations of the angularity of the air stream with respect to the vertical tail for a rolling airplane, the interference effects of the wing being taken into account. A discussion of the factors which enter into the calculations is given and equations for applying the side-wash results to the determination of the tail contributions to the rolling-stability derivatives are included. The results are compared with some available experimental data."
Date: January 24, 1951
Creator: Michael, William H., Jr.
Partner: UNT Libraries Government Documents Department
open access

Investigation of frequency-response characteristics of engine speed for a typical turbine-propeller engine

Description: Experimental frequency-response characteristics of engine speed for a typical turbine-propeller engine are presented. These data were obtained by subjecting the engine to sinusoidal variations of fuel flow and propeller-blade-angle inputs. Correlation is made between these experimental data and analytical frequency-response characteristics obtained from a linear differential equation derived from steady-state torque-speed relations.
Date: March 24, 1950
Creator: Taylor, Burt L., III & Oppenheimer, Frank L.
Partner: UNT Libraries Government Documents Department
open access

Theory of self-excited mechanical oscillations of helicopter rotors with hinged blades

Description: Vibrations of rotary-wing aircraft may derive their energy from the rotation of the rotor rather than from the air forces. A theoretical analysis of these vibrations is described and methods for its application are explained in Chapter one. Chapter two reports the results of an investigation of the mechanical stability of a rotor having two vertically hinged blades mounted upon symmetrical supports, that is, of equal stiffness and mass in all horizontal directions. Chapter three presents the th… more
Date: August 24, 1956
Creator: Coleman, Robert P. & Feingold, Arnold M.
Partner: UNT Libraries Government Documents Department
open access

Influence of Alloying upon Grain-Boundary Creep

Description: "Grain-boundary displacement, occurring in bicrystals during creep at elevated temperature (350 degrees c), has been measured as a function of the copper content (0.1 to 3 percent) in a series of aluminum-rich aluminum-copper solid-solution alloys. The minimums in stress and temperature, below which grain-boundary motion does not occur, increase regularly with the copper content as would be expected if recovery is necessary for movement. Otherwise, the effects, if any, of the copper solute upon… more
Date: June 24, 1955
Creator: Rhines, F. N.; Bond, W. E. & Kissel, M. A.
Partner: UNT Libraries Government Documents Department
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Effect of horizontal-tail span and vertical location on the aerodynamic characteristics of an unswept tail assembly in sideslip

Description: "An investigation has been conducted in the Langley stability tunnel on a vertical-tail model with a stub fuselage in combination with various horizontal tails to determine the effect of horizontal-tail span and vertical location of the horizontal tail relative to the vertical tail on the aerodynamic characteristics of an unswept tail assembly in sideslip. The results of the investigation indicated that the induced loading carried by the horizontal tail produced a rolling moment about the point… more
Date: December 24, 1952
Creator: Riley, Donald R.
Partner: UNT Libraries Government Documents Department
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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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A high-speed motion-picture study of normal combustion, knock and preignition in a spark-ignition engines

Description: Combustion in a spark-ignition engine was investigated by means of the NACA high-speed motion-picture cameras. This camera is operated at a speed of 40,000 photographs a second and therefore makes possible the study of changes that take place in the intervals as short as 0.000025 second. When the motion pictures are projected at the normal speed of 16 frames a second, any rate of movement shown is slowed down 2500 times. Photographs are presented of normal combustion, of combustion from preigni… more
Date: July 24, 1940
Creator: Rothrock, A. M.; Spencer, R. C. & Miller, Cearcy D.
Partner: UNT Libraries Government Documents Department
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An apparatus for measuring rates of discharge of a fuel-injection system

Description: From Introduction: "An apparatus that gives a quick and an accurate measurement of the rate of discharge has been has been designed by the NACA and is described in this report."
Date: March 24, 1941
Creator: Dutee, Francis J.
Partner: UNT Libraries Government Documents Department
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Longitudinal Stability and Control With Special Reference to Slipstream Effects

Description: Report presents the results of a study of data obtained in the NACA full-scale wind tunnel concerning the effects of interference and of propeller operation on longitudinal stability and control. The data include pitching moments for various power conditions for airplanes with tails removed and with tails set at various stabilizer and elevator angles. A number of surveys of the dynamic pressure and the flow direction in the region of the horizontal tail surface are also included.
Date: August 24, 1939
Creator: Katzoff, S.
Partner: UNT Libraries Government Documents Department
open access

Wind-tunnel investigation of NACA 23012 airfoil with various arrangements of slotted flaps

Description: "An investigation was made in the NACA 7 by 10-foot wind tunnel of a large-chord NACA 23012 airfoil with several arrangements of 25.66 percent chord slotted flaps to determine the section aerodynamic characteristics as affected by slot shape, flap shape, flap location, and flap deflection. The flap position for maximum lift, the polars for arrangements considered favorable for take-off and climb, and the complete section aerodynamic characteristics for selected optimum arrangements were determi… more
Date: February 24, 1939
Creator: Wenzinger, Carl J. & Harris, Thomas A.
Partner: UNT Libraries Government Documents Department
open access

A Theoretical Study of the Moment on a Body in a Compressible Fluid

Description: "The extension to a compressible fluid of Lagally's theorem on the moment on a body in an incompressible fluid and Poggi's method of treating the flow of compressible fluids are employed for the determination of the effect of compressibility on the moment of an arbitrary body. Only the case of the two-dimensional subsonic flow of an ideal compressible fluid is considered. As examples of the application of the general theory, two well-known systems of profiles are treated; namely the elliptic pr… more
Date: March 24, 1939
Creator: Kaplan, Carl
Partner: UNT Libraries Government Documents Department
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Experimental Verification of the Theory of Oscillating Airfoils

Description: "Measurements have been made of the lift on an airfoil in pitching oscillation with a continuous-recording, instantaneous-force balance. The experimental values for the phase difference between the angle of attack and the lift are shown to be in close agreement with theory" (p. 619).
Date: April 24, 1939
Creator: Silverstein, Abe & Joyner, Upshur T.
Partner: UNT Libraries Government Documents Department
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Experiments on Drag of Revolving Disks, Cylinders, and Streamline Rods at High Speeds

Description: An experimental investigation concerned primarily with the extension of test data on the drag of revolving disks, cylinders, and streamline rods to high Mach numbers and Reynolds numbers is presented. A Mach number of 2.7 was reached for revolving rods with Freon 113 as the medium. The tests on disks extended to a Reynolds number of 7,000,000" (p. 367).
Date: April 24, 1944
Creator: Theodorsen, Theodore & Regier, Arthur
Partner: UNT Libraries Government Documents Department
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Pressure Distribution Over Airfoils With Fowler Flaps

Description: Report presents the results of tests made of a Clark y airfoil with a Clark y Fowler flap and of an NACA 23012 airfoil with NACA Fowler flaps. Some of the tests were made in the 7 by 10-foot wind tunnel and others in the 5-foot vertical wind tunnel. The pressures were measured on the upper and lower surfaces at one chord section both on the main airfoils and on the flaps for several angles of attack with the flaps located at the maximum-lift settings.
Date: November 24, 1937
Creator: Wenzinger, Carl J. & Anderson, Walter B.
Partner: UNT Libraries Government Documents Department
open access

The Effect of Humidity on Engine Power at Altitude

Description: "From tests made in the altitude chamber of the Bureau of Standards, it was found that the effect of humidity on engine power is the same at altitudes up to 25,000 feet as at sea level. Earlier tests on automotive engines, made under sea-level conditions, showed that water vapor acts as an inert diluent, reducing engine power in proportion to the amount of vapor present. By combining the effects of atmospheric pressure, temperature, and humidity, it is shown that the indicated power obtainable … more
Date: February 24, 1932
Creator: Brooks, D. B. & Garlock, E. A.
Partner: UNT Libraries Government Documents Department
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A comparison between the theoretical and measured longitudinal stability characteristics of an airplane

Description: This report covers an investigation of the application of the theory of dynamic longitudinal stability, based on the assumption of small oscillations, to oscillations an airplane is likely to undergo in flight. The investigation was conducted with a small parasol monoplane for the fixed-stick condition. The period and damping of longitudinal oscillations were determined by direct measurements of oscillations in flight and also by calculation in which the factors that enter the theoretical stabi… more
Date: June 24, 1932
Creator: Soulé, Hartley A. & Wheatley, John B.
Partner: UNT Libraries Government Documents Department
open access

Wing Characteristics as Affected by Protuberances of Short Span

Description: "The drag and interference caused by short-span protuberances from the surface of an airfoil have been investigated in the NACA variable-density wind tunnel at a Reynolds number of approximately 3,100,000, based on the chord length of the airfoil. The effects of variations of protuberance span length, span position, and shape were measured by determining how the wing characteristics were affected by the addition of the various protuberances" (p. 155).
Date: October 24, 1932
Creator: Jacobs, Eastman N. & Sherman, Albert
Partner: UNT Libraries Government Documents Department
open access

Penetration and Duration of Fuel Sprays From a Pump Injection System

Description: "High-speed motion pictures were taken of individual fuel sprays from a pump injection system. The changes in the spray-tip penetration with changes in the pump speed, injection-valve opening and closing pressures, discharge-orifice area, injection-tube length and diameter, and pump throttle setting were measured. The pump was used with and without a check valve" (p. 241).
Date: August 24, 1931
Creator: Rothrock, A. M. & Marsh, E. T.
Partner: UNT Libraries Government Documents Department
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