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296 Matching Results
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Supersonic Flow Around Circular Cones at Angles of Attack
Note presenting an analysis of the flow around cones without axial symmetry and moving at supersonic velocity. The results of the analysis are applied to the determination of flow around circular cones at small angles of attack. It is shown that good agreement with experimental results can be obtained from the first-order theory if the complete equation for the pressure distribution is used.
Date:
November 1950
Creator:
Ferri, Antonio
System:
The UNT Digital Library
Flexural Fatigue Strengths of Riveted Box Beams - Alclad 14S-T6, Alclad 75S-T6, and Various Tempers of Alclad 24S
Note presenting flexural fatigue tests made on riveted box beams of 14S-T6, 75S-T6, and various tempers of 24S alclad aluminum-alloy sheet in order to gain new knowledge of the fatigue strength of built-up structures. Of the five alloy-temper combinations studied in riveted box-beam sections, the flexural fatigue strengths were found to lie in a rather narrow band and no one combination was found to have higher strength values than all others for the entire range of fatigue life covered in these tests.
Date:
November 1951
Creator:
Eaton, I. D. & Holt, Marshall
System:
The UNT Digital Library
Discrepancies Between Theoretical and Observed Behavior of Cyclically Loaded Bearings
Note presenting an analysis of discrepancies between theory and the experimental behavior of a cyclically loaded shaft rotating in a sleeve bearing. For constant loads rotating at one-half the frequency of shaft rotation, eccentricity ratios were found to be unity when kerosene was used to lubricate the test bearing.
Date:
November 1951
Creator:
Dayton, R. W.; Simons, E. M. & Fend, F. A.
System:
The UNT Digital Library
Viscosities of Air and Nitrogen at Low Pressures
Note presenting information from the results of an investigation to measure the true viscosities of nitrogen and air at a range of pressures and temperatures. Results regarding the region of slip and region of free-molecule viscosity are provided.
Date:
November 1951
Creator:
Johnston, Herrick L.; Mattox, Robert W. & Powers, Robert W.
System:
The UNT Digital Library
An Investigation by the Hodograph Method of Flow Through a Symmetrical Nozzle With Locally Supersonic Regions
Note presenting a study of the flow of a compressible fluid through a channel with locally supersonic regions by using the Tricomi equation in the hodograph variables as an approximation in the sonic region to the equation of flow of an irrotational, inviscid gas. It is shown that this is equivalent to studying the flow of a gas with a pressure-density relation matching the isentropic relation to the third derivative at the sonic point. As specific examples, flows are computed with Mach number equal to unity and to 0.86 at the center of the throat section.
Date:
November 1951
Creator:
Ehlers, F. Edward & Cohen, Hirsh G.
System:
The UNT Digital Library
A Graphical Method for Plotting Amplitude and Phase Angle of Transfer Functions of Dynamic Systems Without Factoring Polynomials
"A method is presented for obtaining amplitude and single plots for rational algebraic functions of an imaginary variable. Application of the method is illustrated by an example in which the frequency response of an automatically controlled aircraft is plotted. The method involves the use of templets but does not require the factoring of polynomials" (p. 1).
Date:
November 1951
Creator:
Smith, Earl F.
System:
The UNT Digital Library
Theoretical aerodynamic characteristics of a family of slender wing-tail-body combinations
The aerodynamic characteristics of an airplane configuration composed of a swept-back, nearly constant chord wing and a triangular tail mounted on a cylindrical body are presented. The analysis is based on the assumption that the free-stream Mach number is near unity or that the configuration is slender. The calculations for the tail are made on the assumption that the vortex system trailing back from the wing is either a sheet lying entirely in the plane of the flat tail surface or has completely "rolled up" into two point vortices that lie either in, above, or below the plane of the tail surface.
Date:
November 1951
Creator:
Lomax, Harvard & Byrd, Paul F.
System:
The UNT Digital Library
Infrared Spectra of 59 Dicyclic Hydrocarbons
"The infrared spectra are presented for 59 dicyclic hydrocarbons consisting of some diphenylalkanes, dicyclohexyalkanes, alkylbiphenyls and alkylbicyclohexyls ranging from C(sub 12) through C(sub 18). The physical properties of these compounds, which were available in a high state of purity, are tabulated for reference purposes" (p. 1).
Date:
November 1951
Creator:
Serijan, K. T.; Goodman, I. A. & Yankauskas, W. J.
System:
The UNT Digital Library
Theoretical and Experimental Investigation of Condensation of Air in Hypersonic Wind Tunnels
Note presenting a theoretical and experimental investigation of the condensation of air in hypersonic wind tunnels. The condensation was detected and measured by condensation-fog light scattering, static-pressure measurements, and changes in wedge shock angles at degrees of supersaturation lower than those predicted by existing condensation theory.
Date:
November 1951
Creator:
Stever, H. Guyford & Rathbun, Kenneth C.
System:
The UNT Digital Library
A Survey of Creep in Metals
"This report summarizes numerous theories relating to creep phenomena and the extent of current knowledge on the subject. Various possible mechanisms by which creep occurs both in single crystals and in polycrystals are described. An extensive bibliography of published works in this field is also included" (p. 1).
Date:
November 1951
Creator:
Schwope, A. D. & Jackson, L. R.
System:
The UNT Digital Library
The Synthesis and Purification of Aromatic Hydrocarbons 4: 1,2,3-Trimethylbenzene
"A six gallon quantity of 1,2,3-trimethylbenezene was prepared and purified in a four-step synthesis involving the condensation of 1,3-pentadiene with crotonaldehyde. The dimethylcyclohexencarboxaldehydes formed were hydrogenated to give the corresponding isomeric dimethylcyclohexylcarbinols. The dehydration of the carbinols and the subsequent dehydrogenation of the trimethylcyclohexenes yielded the 1,2,3-trimethylbenzene. The overall yield was 24 percent; the physical properties of the materials are given" (p. 1).
Date:
November 1946
Creator:
Lamberti, J. M.; Reynolds, T. W. & Chanan, H. H.
System:
The UNT Digital Library
Influence of wing flexibility on force-time relation in shock strut following vertical landing impact
Report presenting testing to determine the force developed in a shock strut as a function of the flexibility of the attached wing structure. Both the experiment and analysis indicated that wing flexibility had some effect on the shape and peak value of the force-time curve in a shock strut.
Date:
November 1949
Creator:
McPherson, Albert E.; Evans, J., Jr. & Levy, Samuel
System:
The UNT Digital Library
Stability derivatives of thin rectangular wings at supersonic speeds: Wing diagonals ahead of tip mach lines
Report presenting theoretical results for the surface-velocity-potential functions, surface-pressure distributions, and stability derivatives for various motions at supersonic speeds of thin flat rectangular wings without dihedral. The investigation included steady and accelerating vertical and longitudinal motions and steady rolling, yawing, sideslipping, and pitching for Mach numbers are provided.
Date:
November 1948
Creator:
Harmon, Sidney M.
System:
The UNT Digital Library
Two-dimensional compressible flow in conical mixed-flow compressors
Report presenting a general method of analysis developed for the two-dimensional, steady, compressible flow through mixed-flow compressors in which the center line of the passage generates a right circular cone about the axis of the compressor. The two-dimensional, radial-discharge compressor is a special case in which the cone angle is equal to 180 degrees. The general analysis also applies to inward-flow turbines.
Date:
November 1948
Creator:
Stanitz, John D.
System:
The UNT Digital Library
An analysis of the errors in curve-fitting problems with an application to the calculation of stability parameters from flight data
From Introduction: "It is shown in the body of this report that the solution to the error problem depends upon a more or less arbitrary definition, the only criterion as to the choice of the definition being the usefulness of the solution to which it leads. In this respect, it may be said of the method derived herein that it is not difficult to apply and appears to lead reasonable values of the errors."
Date:
November 1952
Creator:
Shinbrot, Marvin
System:
The UNT Digital Library
Torsion tests of aluminum-alloy stiffened circular cylinders
Second report in a series presenting torsion testing on aluminum-alloy stiffened circular cylinders. The cylinders were similar to those from the first test with the exception of the wall thickness. Results regarding the action before buckling, buckling of curved panels, tension-field action, and ultimate torsional strengths are provided.
Date:
November 1952
Creator:
Clark, J. W. & Moore, R. L.
System:
The UNT Digital Library
Fatigue Investigation of Full-Scale Transport-Airplane Wings: Variable-Amplitude Tests with a Gust-Loads Spectrum
Report presenting results of simulated flight-history testing, which is part of a research program on the fatigue strength of the wings of C-46 airplanes. Testing was conducted using a forced-vibration method, in which a spectrum of loads derived from gust-frequency statistics was used. Results regarding crack initiation and classification, fatigue-crack propagation, final failure, and a lifetime comparison are provided.
Date:
November 1957
Creator:
Whaley, Richard E.
System:
The UNT Digital Library
Effect of a Rapid Blade-Pitch Increase on the Thrust and Induced-Velocity Response of a Full-Scale Helicopter Rotor
From Summary: "A method has been proposed for predicting the effect of a rapid blade-pitch increase on the thrust and induced-velocity response of a helicopter rotor. General equations have been derived for the ensuing motion of the helicopter. These equations yield time histories of thrust, induced velocity, and helicopter vertical velocity for given rates of blade-pitch-angle changes and given rotor-angular-velocity time histories. The results of the method have been compared with experimental results obtained with a rotor mounted on the Langley helicopter test tower."
Date:
November 1953
Creator:
Carpenter, Paul J. & Fridovich, Bernard
System:
The UNT Digital Library
Theoretical calculations of the effects of finite sideslip at supersonic speeds on the span loading and rolling moment for families of thin sweptback tapered wings at an angle of attack
Report presenting some results obtained from a general investigation of the effects of sideslip on the aerodynamic characteristics of thin sweptback tapered wings with side edges parallel to the axis of wing symmetry. Span load distributions have been calculated for several families of wings sideslipping at an angle of attack.
Date:
November 1953
Creator:
Sherman, Windsor L. & Margolis, Kenneth
System:
The UNT Digital Library
Experimental Investigation of the Effects of Cooling on Friction and on Boundary-Layer Transition for Low-Speed Gas Flow at the Entry of a Tube
Note presenting an investigation of the effect of cooling on boundary-layer transition in the steady flow of air in the entrance of a smooth round tube. The primary purpose was to investigate the practical possibilities of delaying the transition point, and thus increasing the transition Reynolds number, by cooling the laminar boundary layer in a gas. The results indicate that the effect of cooling on transition is not likely to be significant in any normal internal flow.
Date:
November 1953
Creator:
Kline, Stephen J. & Shapiro, Ascher H.
System:
The UNT Digital Library
Low-speed drag of cylinders of various shapes
Report presenting an investigation to find the approximate variation of the drag coefficient with Reynolds number of several cylinders with different cross-sectional shapes. Data were obtained for circular cylinders, elliptical cylinders of two fineness ratios, rectangular and diamond cylinders of three fineness ratios, and two isosceles triangular cylinders.
Date:
November 1953
Creator:
Delany, Noel K. & Sorensen, Norman E.
System:
The UNT Digital Library
Experimental stress analysis of stiffened cylinders with cutouts: Pure torsion
Torsion tests were made on a cylindrical semimonocoque shell of circular cross section. The cylinder was first tested without a cutout, and then with a rectangular cutout which was successively enlarged through six sizes varying from 30 degrees to 130 degrees in circumference and from 1 to 2 bays in length. Strain measurements were made with resistance-type wire strain gages near the cutout on the stringers, the skin, and the rings for each size of cutout, and the stresses obtained are presented in tables. (author).
Date:
November 1953
Creator:
Schlechte, Floyd R. & Rosecrans, Richard
System:
The UNT Digital Library
Use of two-dimensional data in estimating loads on a 45 degree sweptback wing with slats and partial-span flaps
Report presenting a study of the application of two-dimensional data and span-loading theory for estimating the local loading characteristics on a swept wing with flaps. Estimated results are compared with results measured at large scale on a 45 degree sweptback wing of aspect ratio 6 with a 0.4-span double-slotted flap. Results regarding chordwise loading, spanwise loading, and local lift curves are provided.
Date:
November 1953
Creator:
Hunton, Lynn W. & James, Harry A.
System:
The UNT Digital Library
Summary of revised gust-velocity data obtained from V-G records taken on civil transport airplanes from 1933 to 1950
Report presenting gust-velocity data obtained by reevaluating the normal accelerations and airspeeds from V-G records taken on civil transport airplanes from 1933 to 1950. The reevaluation was made on the basis of a derived gust velocity, which is related to the effective gust velocity by a conversion factor that is a function of the type of airplane and operating altitude.
Date:
November 1953
Creator:
Walker, Walter G.
System:
The UNT Digital Library