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Two-Dimensional Irrotational Transonic Flows of a Compressible Fluid
The methods of NACA TN No. 995 have been slightly modified and extended in include flows with circulation by considering the alteration of the singularities of the incompressible solution due to the presence of the hypergeometric functions in the analytic continuation of the solution. It was found that for finite Mach numbers the only case in which the nature of the singularity can remain unchanged is for a ratio of specific heats equal to -1. From a study of two particular flows it seems that the effect of geometry cannot be neglected, and the conventional "pressure-correction" formulas are not valid, even in the subsonic region if the body is thick, especially if there is a supersonic region in the flow.
Date:
June 1948
Creator:
Kuo, Yung-Huai
System:
The UNT Digital Library
Tables for the Computation of Wave Drag of Arrow Wings of Arbitrary Airfoil Section
Tables and computing instructions for the rapid evaluation of the wave drag of delta wings and of arrow wings having a ration of the tangent of the trailing-edge sweep angle to the tangent of the leading-edge sweep angle in the range from -1.0 to 0.8. The tables cover a range of both subsonic and supersonic leading edges.
Date:
June 1954
Creator:
Grant, Frederick C. & Cooper, Morton
System:
The UNT Digital Library
An approximate spin design criterion for monoplanes
"A quantitative criterion of merit has been needed to assist airplane designers to incorporate satisfactory spinning characteristics into new designs. An approximate empirical criterion, based on the projected side area and the mass distribution of the airplane, has been formulated in a recent British report. In the present paper, the British results have been analyzed and applied to American designs. A simpler design criterion based solely on the type and the dimensions of the tail, has been developed: it is useful in a rapid estimation of whether a new design is likely to comply with the minimum requirements for safety in spinning" (p. 1).
Date:
June 1939
Creator:
Seidman, Oscar & Donlan, Charles J.
System:
The UNT Digital Library
Effects of Some Present-Day Airplane Design Trends on Requirements for Lateral Stability
Note presenting computations made to determine the effects of some airplane design trends on the fin area and the dihedral angle required for lateral stability. The specific factors studied were wing loading, moments of inertia in roll and yaw, wing chord, and tail length. The results of the computations are presented in the form of diagrams of variations of fin area with dihedral angle for neutral stability.
Date:
June 1941
Creator:
Bamber, Millard J.
System:
The UNT Digital Library
Effects of Range of Stress and of Special Notches on Fatigue Properties of Aluminum Alloys Suitable for Airplane Propellers
"Laboratory tests were made to obtain information on the load-resisting properties of X76S-T aluminum alloy when subjected to static, impact, and repeated loads. Results are presented from static-load test of unnotched specimens in tension and in torsion and of notched specimens in tension. Charpy impact values obtained from bend tests on notched specimens and tension impact values for both notched and unnotched specimens tested at several different temperatures are included" (p. 1).
Date:
June 1942
Creator:
Dolan, Thomas J.
System:
The UNT Digital Library
Acoustical Treatment for the NACA 8- by 6-Foot Supersonic Propulsion Wind Tunnel
"This report presents results of a research and engineering program performed during the first half of 1950 that resulted in an acoustical treatment for the 8- by 6-foot supersonic wind tunnel at the Lewis Flight Propulsion Laboratory" (p. 1).
Date:
June 1955
Creator:
Beranek, Leo L.; Labate, Samuel & Ingard, Uno
System:
The UNT Digital Library
Wind-tunnel investigation of the effect of clipping the tips of triangular wings of different thickness, camber, and aspect ratio - transonic bump method
Report presenting an investigation on a transonic bump to determine the aerodynamic characteristics of a series of triangular wings. Four basic triangular-wing plan forms with different aspect ratios, taper ratios, and combinations of tip clipping were tested over a range of Mach and Reynolds numbers. Results regarding angle of attack, drag coefficient, pitching-moment coefficient with lift coefficient, and various curves are provided.
Date:
June 1956
Creator:
Emerson, Horace F.
System:
The UNT Digital Library
Design and experimental evaluation of a light-weight turbine-wheel assembly
Report presenting lightweight design concepts, which were developed and tested in a full-scale turbine wheel with a tip diameter of 34.3 inches and a tip speed of 1190 feet per second. It consisted of a rotor of two thin alloy disks attached with spacers and bolts and hollow turbine blades. Testing indicated that it would be particularly applicable to an expendable missile engine.
Date:
June 1957
Creator:
Morgan, W. C. & Kemp, R. H.
System:
The UNT Digital Library
Effect of the proximity of the wing first-bending frequency and the short-period frequency on the airplane dynamic-response factor
Report presenting a study of the effect of the frequency of the lowest wing structural mode on the airplane center-of-gravity dynamic-response factor was made my employing simplified transfer functions.
Date:
June 1958
Creator:
Huss, Carl R. & Donegan, James J.
System:
The UNT Digital Library
Stresses in and general instability of monocoque cylinders with cutouts 2: calculation of the stresses in a cylinder with a symmetric cutout
A numerical procedure is presented for the calculation of the stresses in a monocoque cylinder with a cutout. In the procedure the structure is broken up into a great many units; the forces in these units corresponding to specified distortions of the units are calculated; a set of linear equations is established expressing the equilibrium conditions of the units in the distorted state; and the simultaneous linear equations are solved. A fully worked out numerical example, corresponding to the application of a pure bending moment, gave results in good agreement with experiments carried out earlier at the Polytechnic Institute of Brooklyn.
Date:
June 1946
Creator:
Hoff, N. J.; Boley, Bruno A. & Klein, Bertram
System:
The UNT Digital Library
Flight Measurements of the Vibratory Bending and Torsional Stresses on a Modified Supersonic Propeller for Forward Mach Numbers up to 0.95
Note presenting vibratory stress measurements obtained in flight on a modified supersonic propeller for forward mach numbers up to 0.95. The magnitude of the vibratory bending stress was low in relation to the strength of the material throughout the flight range of the airplane. Results of a propeller feathering operation at a Mach number of 0.95 indicated no excessive stresses.
Date:
June 1958
Creator:
O'Bryan, Thomas C.
System:
The UNT Digital Library
Results of an experimental investigation of small viscous dampers
Report presenting the results of an experimental investigation of several small viscous dampers. The characteristics of the dampers are presented in the form of the magnitudes of the damping forces and spring forces as a function of the maximum velocity of the piston. The results indicated that the temperature has a large effect on the force produced by the dampers and demonstrated the necessity for consideration of the heat generated and dissipated as a result of work done by the dampers.
Date:
June 1958
Creator:
Silveira, Milton A.; Maglieri, Domenic J. & Brooks, George W.
System:
The UNT Digital Library
A numerical method for evaluating wave drag
"A numerical method for evaluating the Von Karman wave-drag equation has been developed and applied to the calculation of wave drag for several bodies of revolution. Results indicated good agreement with the exact solution. Sufficient accuracy of wave drag was obtained by using a simple numerical method to determine the second derivatives of the area distributions" (p. 1).
Date:
June 1958
Creator:
Cahn, Maurice S. & Olstad, Walter B.
System:
The UNT Digital Library
Flutter analysis of rectangular wings of very low aspect ratio
Report presenting a flutter analysis for rectangular wings of very low aspect ratio with a constant thickness, which used slender-body aerodynamic theory and thin-plate theory. The results show that the variation of flutter speed and mode shape with aspect ratio. Approximation of the chordwise deflection shape by use of parabolic or cubic curves yields flutter speeds in fair agreement with those of the "exact" theory for a ratio of chord to semispan less than 3 with the cubic approximation giving almost exact results.
Date:
June 1958
Creator:
Fralich, Robert W. & Hedgepeth, John M.
System:
The UNT Digital Library
Further Investigation of Fatigue-Crack Propagation in Aluminum-Alloy Box Beams
Report presenting testing of twenty-one box beams constructed according to nine designs that were subjected to fatigue tests at one load level to study fatigue-crack propagation and accompanying stress redistribution. Six designs had stiffeners riveted to the skin, two had integrally stiffened covers, and one had stiffeners bonded to the skin. Results regarding crack initiation, crack propagation, and stresses are provided.
Date:
June 1958
Creator:
Hardrath, Herbert F. & Leybold, Herbert A.
System:
The UNT Digital Library
Estimation of Compressible Boundary-Layer Growth Over Insulated Surfaces With Pressure Gradient
Note presenting the incompressible boundary-layer theory of Truckenbrodt extended using a modified Stewartson-type transformation to include compressible boundary-layer development over insulated surfaces. The method is applicable to two-dimensional and axisymmetric, laminar and turbulent boundary layer, and accounts for the pressure gradient along the wall for both compressible and incompressible flow. Some experimental measurements of the boundary layer on small axisymmetric bodies on the wall of a supersonic wind tunnel compared with theoretical predictions.
Date:
June 1957
Creator:
Englert, Gerald W.
System:
The UNT Digital Library
Thermodynamic study of a Roots compressor as a source of high-temperature air
Report presenting an analysis to ascertain the feasibility of using the device to produce high-temperature air. The production of high temperature is associated with the leakage of the hot outlet air through the tip clearance to the inlet and the subsequent mixing with the supply air. The calculated performance of the unit is very sensitive to the assumed value of Stanton number.
Date:
June 1957
Creator:
Cohen, Clarence B.; Woollett, Richard R. & Weston, Kenneth C.
System:
The UNT Digital Library
Experimental investigation of an impulse-type supersonic compressor rotor having a turning of 73 degrees at the mean radius
Report presenting testing of a 16-inch-diameter supersonic impulse rotor with guide vanes in Freon-12. Results regarding the overall performance and blade-element performance are provided.
Date:
June 1958
Creator:
Sterrett, James R.
System:
The UNT Digital Library
Effects of Rapid Heating on Strength of Airframe Components
Note presenting results of several experimental investigations which indicate the effects of rapid heating on the bending strength of multiweb beams and ring-stiffened cylinders. Thermal stresses are shown to reduce the bending load carried at buckling by both beams and cylinders.
Date:
June 1957
Creator:
Pride, Richard A.; Hall, John B., Jr. & Anderson, Melvin S.
System:
The UNT Digital Library
Two Factors Influencing Temperature Distributions and Thermal Stresses in Structures
"The influence of joint conductivity and internal radiation on temperature distribution and thermal stresses has been discussed. Joints of poor conductivity can occur in normal fabrication procedure and greatly alter temperature distributions and increase thermal stresses. On the other hand, internal radiation tends to make the temperature distributions more uniform and thereby relieves thermal stress" (p. 1).
Date:
June 1957
Creator:
Brooks, William A., Jr.; Griffith, George E. & Strass, H. Kurt
System:
The UNT Digital Library
The combinations of thermal and load stresses for the onset of permanent buckling in plates
A simple and practical method for evaluating the onset of permanent buckling in plates in the presence of combined thermal and compressive load stresses is outlined. A particular application of the method shows reasonable agreement with tests of 17-7 PH stainless-steel square tubes. The results indicate that the compressive load stress which the plate can support at the onset of permanent buckling is substantially reduced as the temperature difference of the plate and adjoining members increases.
Date:
June 1957
Creator:
Zender, George W. & Pride, Richard A.
System:
The UNT Digital Library
Adaptor for Measuring Principal Strains With Tuckerman Strain Gage
Report discussing an adapter which uses three Tuckerman optical strain gages to measure the displacement of the three vortices of an equilateral triangle along lines 120 degrees apart. These displacements are substituted in well-known equations in order to compute the magnitude and direction of the principal strains. Tests of the adaptor indicate that principal strains over a gage length of 1.42 inch may be measured with a systematic error not exceeding 4 percent and a mean observational error of the order of + or minus 0.000006. The maximum observed error in strain was of the order of 0.00006. The directions of principal strains for unidirectional stress were measured with the adaptor with an average error of the order of 1 degree.
Date:
June 1943
Creator:
McPherson, A. E.
System:
The UNT Digital Library
Effect of Transient Heating on Vibration Frequencies of Some Simple Wing Structures
"Thermal stresses, which may result from transient heating, can cause changes in the effective stiffness of wing structures. Some effects of this change in stiffness were investigated experimentally by radiantly heating three types of simple wing structures: a uniform plate, a solid double-wedge section, and a circular-arc multiweb-wing section. Changes in stiffness were determined by measuring the changes in natural frequency of vibration during transient heating. Some comparisons are made between theoretical calculations and the measured data" (p. 1).
Date:
June 1957
Creator:
Vosteen, Louis F.; McWithey, Robert R. & Thomson, Robert G.
System:
The UNT Digital Library
Normal-pressure tests of circular plates with clamped edges
A fixture is described for making normal-pressure tests of flat plates 5 inches in diameter in which particular care was taken to obtain rigid clamping at the edges. Results are given for 19 plates, ranging in thickness from 0.015 to 0.072 inch. The center deflections and the extreme-fiber stresses at low pressures were found to agree with theoretical values; the center deflections at high pressures were 4 to 12 percent greater than the theoretical values. Empirical curves are derived of the pressure for the beginning of permanent set as a function of the dimensions of the plate and the tensile properties of the material.
Date:
June 1942
Creator:
McPherson, Albert E.; Ramberg, Walter & Levy, Samuel
System:
The UNT Digital Library