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Methods of Analyzing Wind-Tunnel Data for Dynamic Flight Conditions
"The effects of power on the stability and the control characteristics of an airplane are discussed and methods of analysis are given for evaluating certain dynamic characteristics of the airplane that are not directly discernible from wind-tunnel tests alone. Data are presented to show how the characteristics of a model tested in a wind tunnel are affected by power. The response of an airplane to a rolling and a yawing disturbance is discussed, particularly in regard to changes in wing dihedral and fin area" (p. 1).
Date:
October 1941
Creator:
Donlan, C. J. & Recant, I. G.
System:
The UNT Digital Library
Aerodynamic heating and the deflection of drops by an obstacle in an air stream in relation to aircraft icing
From Summary: "Two topics of interest to persons attempting to apply the heat method of preventing ice formation on aircraft are considered. Surfaces moving through air at high speed are shown, both theoretically and experimentally, to be subject to important aerodynamic heating effects that will materially reduce the heat required to prevent ice. Numerical calculations of the path of water drops in an air stream around a circular cylinder are given. From these calculations, information is obtained on the percentage of the swept area cleared of drops."
Date:
October 1940
Creator:
Kantrowitz, Arthur
System:
The UNT Digital Library
Investigations Relating to the Extension of Laminar Flow by Means of Boundary-Layer Suction Through Slots
Note presenting experimental investigations of boundary-layer suction through slots as a means of increasing the extent of laminar flow on airfoil sections. The results show that, with the use of suitable slots, substantial increases in the extent of laminar flow can be achieved by boundary-layer control with only a small expenditure of power. Results regarding slot geometry and arrangement, suction slots in an unfavorable pressure gradient, suction slots in a favorable pressure gradient, and determinations of the relations controlling the distribution of suction slots are provided.
Date:
October 1949
Creator:
Loftin, Laurence K., Jr. & Burrows, Dale L.
System:
The UNT Digital Library
Flow Tests of an NACA-Designed Supercharger Inlet Elbow and the Effects of Various Components on the Flow Characteristics at the Elbow Outlet
Note presenting an investigation on a supercharger inlet elbow designed to have a uniform velocity distribution at the outlet with a minimum pressure loss through the bend. The effects of a vane, an impeller-shaft housing, and the combination of the two on the outlet-velocity distribution and total pressure drop through the elbow were determined.
Date:
October 1946
Creator:
Guentert, D. C.; Todd, D. J. & Simmons, W. P., Jr.
System:
The UNT Digital Library
A Relaxation Procedure for the Stress Analysis of a Continuous Beam-Column Elastically Restrained Against Deflection and Rotation at the Supports
Note presenting a method of stress analysis for a continuous beam-column supported by deflectional and rotational springs. The principal feature of the method is the use of a relaxation procedure to determine the deflections and rotations of the supports. The shears and moments at the supports and between the supports can then be calculated with the aid of sample equations and graphs.
Date:
October 1946
Creator:
Hu, Pai C. & Libove, Charles
System:
The UNT Digital Library
Flight investigation of the cooling characteristics of a two-row radial engine installation 3: engine temperature distribution
From Summary: "The temperature distribution of a two-row radial engine in a twin-engine airplane has been investigated in a series of flight tests. The test engine was operated over a wide range of conditions at density altitudes of 5000 and 20,000 feet; quantitative results are presented showing the effects of flight and engine variables upon average engine temperature and over-all temperature spread. Discussions of the effect of the variables on the shape of the temperature patterns and on the temperature distribution of individual cylinders are also included."
Date:
October 1946
Creator:
Rennak, Robert M.; Messing, Wesley E. & Morgan, James E.
System:
The UNT Digital Library
Tests in the gust tunnel of a model of the XBM-1 airplane
Report presenting testing of a dynamically scaled model of a Navy XBM-1 biplane in the gust tunnel to provide data for use in determining the structure of atmospheric gusts from measurements of the motions of the full-scale airplane in rough air. Records for two flights for several gradients were evaluated to give histories of events during passage through the gust.
Date:
October 1939
Creator:
Donely, Philip & Shufflebarger, C. C.
System:
The UNT Digital Library
Turbosupercharger-Rotor Temperatures in Flight
Note presenting temperatures of a turbosupercharger rotor measured in flight for a variety of conditions by thermocouples, the leads of which were brought away from the turbine by means of rotating slip rings and stationary brushes. A consistent and almost linear relation was shown between turbine temperature at the outer edge of the rim and the effective exhaust-gas temperature at the surfaces of the blades on three successive flights at cruising power.
Date:
October 1946
Creator:
Bartoo, Edward R.
System:
The UNT Digital Library
The infrared spectra of spiropentane methylenecyclobutane and 2-methyl-1-butene
The infrared spectra of spiropentane, methylenecyclobutane, and 2-methyl-1-butene were measured in the region from 3 to 14 microns with a rock salt prism spectrometer of medium dispersion. The pure samples were prepared at the NACA Cleveland Laboratory. The vapors of these three C5 hydrocarbons were investigated at room temperature and at pressures in the range from 80 to 300 millimeters of mercury absolute in a 10-centimeter cell. The spectra were compared with each other and with Ramon spectra for the same compounds.
Date:
October 1946
Creator:
Cleaves, Alden P. & Sherrick, Mildred E.
System:
The UNT Digital Library
Effect of Pressure on the Spontaneous Ignition Temperature of Liquid Fuels
Report presenting an investigation of spontaneous ignition temperatures from 1 to 9 atmospheres in the air for n-heptane, isooctane, benzene, JP-4, and JP-5 fuels. Time lags before ignition were measured at each pressure for all fuels. Results regarding the effect of pressure, general comparisons of all fuels, and ignition-lag experiments are provided.
Date:
October 1956
Creator:
O'Neal, Cleveland, Jr.
System:
The UNT Digital Library
Experimental Investigation of the Strength of Multiweb Beams With Corrugated Webs
"The results of an experimental investigation of the strength of multiweb beams with corrugated webs are reported. Included in the investigation were two types of connection between the web and the skin. A comparison between the structural efficiency of corrugated-web and channel-web multiweb beams is presented, and it is shown that, for a considerable range of the structural index, corrugated-web beams can be built which are structurally more efficient than channel-web beams" (p. 1).
Date:
October 1956
Creator:
Fraser, Allister F.
System:
The UNT Digital Library
Tabulation of Mass-Flow Parameters for Use in Design of Turbomachine Blade Rows for Ratios of Specific Heats of 1.3 and 1.4
Report presenting mass-flow tables for ratios of specific heats for the entire range of critical velocity ratio. The tables enable a quick and accurate determination of the integrated average specific mass flow across a region where the end-point velocities are known. A numerical example using the tables is also provided.
Date:
October 1956
Creator:
Whitney, Warren J.
System:
The UNT Digital Library
Investigation of a related series of turbine-blade profiles in cascade
Report presenting an application of airfoil design methods to a series of related turbine-blade profiles to satisfy the conditions of inlet flow angle and turning angle encountered in the usual range of turbine operation. Satisfactory flow conditions were obtained in all of the blade passages tested. Results regarding the turning angles, wake losses, surface pressure distributions, critical Mach numbers, application of compressibility corrections to low-speed tests, and selection of design camber are provided.
Date:
October 1956
Creator:
Dunavant, James C. & Erwin, John R.
System:
The UNT Digital Library
Band-Pass Shock and Vibration Absorbers for Application to Aircraft Landing Gear
Note presenting a description of a new class of frequency-selective shock absorbers called band-pass shock absorbers, which were conceived as a means of overcoming some of the limitations of conventional shock absorbers. The shock absorbers may be designed to isolate two bodies from each other over certain ranges of exciting frequencies or rates of load application while coupling them over the remainder of the frequency spectrum.
Date:
October 1956
Creator:
Schnitzer, Emanuel
System:
The UNT Digital Library
The Effect of Changing the Ratio of Exhaust-Valve Flow Capacity to Inlet-Valve Flow Capacity on Volumetric Efficiency and Output of a Single-Cylinder Engine
Report presenting a series of tests with a single-cylinder engine in order to determine the effect on volumetric efficiency and on engine performance of changing the ratio of exhaust-valve flow capacity to inlet-valve flow capacity when operating with exhaust pressure equal to inlet pressure.
Date:
October 1947
Creator:
Eppes, James V. D.; Livengood, James C. & Taylor, C. Fayette
System:
The UNT Digital Library
Limits of Precision in the Determination of Lattice Parameters and Stresses by the Debye-Scherrer Method
Note an investigation regarding the limits of precision in the determination of lattice parameters. Experiments were performed with copper radiation on zinc samples. Even when the crystal-grain orientation is perfectly uniform, the recording of the intensity distribution will entail errors.
Date:
October 1947
Creator:
Ekstein, Hans & Siegel, Stanley
System:
The UNT Digital Library
Flight Investigation of the Effect of Atmospheric Turbulence on the Climb Performance of an Airplane
Note presenting the results of an investigation consisting of a series of one-engine climb tests with a twin-engine transport airplane, which indicate that light turbulence of the type generally present in clear air over flat terrain has no significant effect on the average rate of climb for a series of runs. Turbulence does, however, increase the variation in the rate of climb from run to run. Results regarding mean rate of climb, standard deviation of the rate of climb, effects of climb duration, and implications of these results are provided.
Date:
October 1951
Creator:
Press, Harry & McClanahan, Herbert C., Jr.
System:
The UNT Digital Library
Expressions for Measuring the Accuracy of Approximate Solutions to Compressible Flow Through Cascades of Blades With Examples of Use
Report presenting four necessary conditions for steady irrotational compressible flow through a straight cascade of blades as derived from the irrotationality condition and conservation of mass and momentum. The expressions used can only give an approximate solution to the conditions, as there are an infinite number of them.
Date:
October 1951
Creator:
Sinnette, John T., Jr.; Costello, George R. & Cummings, Robert L.
System:
The UNT Digital Library
Interaction of Bearing and Tensile Loads on Creep Properties of Joints
The interaction of bearing and tensile loads on the creep behavior of joints was studied. A specimen was designed for this study which possessed some of the general features of pin and rivet joint connections and an apparatus was constructed to apply both bearing and tensile loads to the joint model. Deformation measurements were made by use of a photogrid printed on the joint model.
Date:
October 1956
Creator:
Bodine, E. G.; Carlson, R. L. & Manning, G. K.
System:
The UNT Digital Library
A low-speed experimental investigation of the effect of a sandpaper type of roughness on boundary-layer transition
Report presenting an investigation in the low-turbulence pressure tunnel to determine the effect of size and location of a sandpaper type of roughness on the Reynolds number for transition. Transition was observed by means of a hot-wire anemometer at various chordwise stations for each position of roughness.
Date:
October 1956
Creator:
von Doenhoff, Albert E. & Horton, Elmer A.
System:
The UNT Digital Library
A Simple Method for Calculating the Characteristics of the Dutch Roll Motion of an Airplane
A simple method for calculating the characteristics of the Dutch roll motion of an airplane is obtained by arranging the lateral equations of motion in such form and order that an iterative process is quickly convergent. Primary effects of variation of the important stability derivatives on the period and damping can be seen more clearly from the iterative method than from the fourth-order characteristic equation.
Date:
October 1956
Creator:
Klawans, Bernard B.
System:
The UNT Digital Library
Tables for the Numerical Determination of the Fourier Transform of a Function of Time and the Inverse Fourier Transform of a Function of Frequency, With Some Applications to Operational Calculus Methods
Report presenting a set of tables which aids in the numerical determination of the Fourier transform of a function of time and the inverse Fourier transform of a function of frequency. Many of the operations normally performed theoretically with the operational calculus can be performed numerically with the aid of the tables. Some applications using the tables are described.
Date:
October 1957
Creator:
Huss, Carl R. & Donegan, James J.
System:
The UNT Digital Library
The compressible laminar boundary layer with heat transfer and small pressure gradient
Report presenting a perturbation method for the calculation of velocity and temperature profiles and skin-friction and heat-transfer characteristics for two-dimensional, compressible laminar boundary layers with heat transfer and a small arbitrary pressure gradient is presented. The combined effects of heat transfer and pressure gradient on boundary-layer characteristics are demonstrated by applying the results of the analysis to two representative wings.
Date:
October 1953
Creator:
Low, George M.
System:
The UNT Digital Library
On the Minimization of Airplane Responses to Random Gusts
Note presenting a theoretical study of the motions experienced by aircraft in response to sharp-edge, harmonic, and random gusts. These are compared with approximate solutions based on commonly used assumptions, and the validity of each of the assumptions is assessed.
Date:
October 1957
Creator:
Tobak, Murray
System:
The UNT Digital Library