Investigations Relating to the Extension of Laminar Flow by Means of Boundary-Layer Suction Through Slots (open access)

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
Quantitative Study of Variations in Concentration of Glycerol and Aerosol OT on Foaming Volume of Oil at Room Temperature (open access)

Quantitative Study of Variations in Concentration of Glycerol and Aerosol OT on Foaming Volume of Oil at Room Temperature

"The amount of foam that can be formed in the presence of certain pure chemical agents was investigated by a new method. The effect of variations in concentration and proportion of Aerosol OT and glycerol was studied and the effects of various other mixtures have been given for comparison. Both Gulf Agent and Aerosol-OT - glycerol mixtures, when present in comparable amounts, prohibited the formation of the normal volumes of foam to the same extent and in the optimum cases reduced it to only one-tenth of its normal value" (p. 1).
Date: April 1949
Creator: McBain, J. W. & Ross, Sydney
System: The UNT Digital Library
Effect of Various Compounds in Use With Airplane Engines Upon Foaming of Aircraft Lubricating Oil (open access)

Effect of Various Compounds in Use With Airplane Engines Upon Foaming of Aircraft Lubricating Oil

Report presenting an investigation of aircraft lubricating oil that is contaminated with various materials used in connection with airplane engines or contained in the fuel. Over 60 of the materials have been tested to determine their influence on the foaming of an aircraft lubricating oil. All but 13 of the compounds were found to have a small or negligible effect, but the other 13 were found to be strong foaming agents.
Date: April 1949
Creator: McBain, J. W. & Woods, W. W.
System: The UNT Digital Library
The Buckling of Parallel Simply Supported Tension and Compression Members Connected by Elastic Deflectional Springs (open access)

The Buckling of Parallel Simply Supported Tension and Compression Members Connected by Elastic Deflectional Springs

Note presenting an investigation of the problem of the buckling of parallel simply supported tension and compression members connected by equally stiff and equally spaced elastic deflection springs as an approximation to the problem of the effect of finite stiffness of ribs and tension surface on the buckling load of the compression surface of a wing. Charts relating compressive buckling load, deflectional spring stiffness, and the ratio of the flexural stiffness of the members are given for tension and compression members with various numbers of spans.
Date: February 1949
Creator: Seide, Paul & Eppler, John F.
System: The UNT Digital Library
Compressive Buckling of Simply Supported Plates With Longitudinal Stiffeners (open access)

Compressive Buckling of Simply Supported Plates With Longitudinal Stiffeners

"Charts are presented for the analysis of the stability under compression of simply supported rectangular plates with one, two, three, and an infinite number of identical equally spaced longitudinal stiffeners that have zero torsional stiffness" (p. 1).
Date: March 1949
Creator: Seide, Paul & Stein, Manuel
System: The UNT Digital Library
Linear theory of boundary effects in open wind tunnels with finite jet lengths (open access)

Linear theory of boundary effects in open wind tunnels with finite jet lengths

Report in two parts: one examines the boundary conditions for an open wind tunnel with special references to the effects of the closed entrance and exit sections, while the other derives solutions of four types of two-dimensional open tunnels, including one in which the pressures on the two free surfaces are not equal.
Date: March 1949
Creator: Katzoff, Samuel; Gardner, Clifford S.; Diesendruck, Leo & Eisenstadt, Bertram J.
System: The UNT Digital Library
Matrix Methods for Calculating Cantilever-Beam Deflections (open access)

Matrix Methods for Calculating Cantilever-Beam Deflections

Note presenting the method of numerical integration for calculation of beam deflection in matrix form to give it the advantages which are inherent in an influence-coefficient method. Examples are presented to show that the use of weighted matrices reduces the calculation time required to obtain a desired degree of accuracy.
Date: March 1949
Creator: Benscoter, Stanley U. & Gossard, Myron L.
System: The UNT Digital Library
Effect of forebody warp on the hydrodynamic qualities of a hypothetical flying boat having a hull length-beam ratio of 15 (open access)

Effect of forebody warp on the hydrodynamic qualities of a hypothetical flying boat having a hull length-beam ratio of 15

Report of an investigation of the effect of forebody warp on the hydrodynamic qualities of a hypothetical flying boat with a hull length-beam ratio of 15 in smooth water and in waves. Warping the forebody planing bottom was found to appreciably increase the range of stable trim between the lower and upper trim limits of stability, although the center-of-gravity limits of stability were reduced.
Date: March 1949
Creator: Carter, Arthur W. & Weinstein, Irving
System: The UNT Digital Library
Data on the Compressive Strength of 75S-T6 Aluminum-Alloy Flat Panels with Longitudinal Extruded Z-Section Stiffeners (open access)

Data on the Compressive Strength of 75S-T6 Aluminum-Alloy Flat Panels with Longitudinal Extruded Z-Section Stiffeners

"The experimental results are presented for a part of an investigation of the compressive strength of 75S-T6 aluminum-alloy flat panels with longitudinal extruded Z-section stiffeners. This part of the investigation is concerned with panels in which the ratio of the thickness of the stiffener material to the skin material varies from 0.4 to 1.0 and the ratio of stiffener spacing to skin thickness varies from 15 to 40" (p. 1).
Date: March 1949
Creator: Hickman, William A. & Dow, Norris F.
System: The UNT Digital Library
Corrosion tests of a heated wing utilizing an exhaust-gas-air mixture for ice prevention (open access)

Corrosion tests of a heated wing utilizing an exhaust-gas-air mixture for ice prevention

Report presenting an investigation of the exhaust of corrosive attack in an aluminum alloy wing employing an exhaust-gas-air mixture as a heating medium for ice prevention. There were no cases of structurally serious corrosion on either painted or plain specimens removed from the wing for detailed microscopic and metallurgic examination.
Date: January 1949
Creator: Holdaway, George H.
System: The UNT Digital Library
Study by the Prandtl-Glauert method of compressibility effects and critical Mach number for ellipsoids of various aspect ratios and thickness ratios (open access)

Study by the Prandtl-Glauert method of compressibility effects and critical Mach number for ellipsoids of various aspect ratios and thickness ratios

From Summary: "By the use of a form of the Prandtl-Glauert method that is valid for three-dimensional flow problems, the value of the maximum incremental velocity for compressible flow about thin ellipsoids at zero angle of attack is calculated as a function of the Mach number for various aspect ratios and thickness ratios. The critical Mach numbers (within the accuracy of the Prandtl-Glauert method) of the various ellipsoids are also determined. The results indicate an increase in critical Mach number with decrease in aspect ratio which is large enough to explain experimental results on low-aspect-ratio wings at zero lift."
Date: January 1949
Creator: Hess, Robert V. & Gardner, Clifford S.
System: The UNT Digital Library
Investigation of Meteorological Conditions Associated with Aircraft Icing in Layer-Type Clouds for 1947-48 Winter (open access)

Investigation of Meteorological Conditions Associated with Aircraft Icing in Layer-Type Clouds for 1947-48 Winter

Rotating-cylinder measurements of the icing conditions encountered in flight during the winter of 1947-48 are presented. Liquid water content, drop size, and temperature data are shown to be consistent with previously measured conditions and with proposed maximum icing conditions in supercooled layer-type clouds. Cumulative frequency graphs of meteorological parameters indicate the frequency with which various icing conditions have been encountered in the Great Lakes area and surrounding states.
Date: January 1949
Creator: Kline, Dwight B.
System: The UNT Digital Library
Gust-tunnel investigation of a wing model with semichord line swept back 30 degrees (open access)

Gust-tunnel investigation of a wing model with semichord line swept back 30 degrees

Report presenting tests in the gust tunnel of the 30 degree sweptback wing model to provide information on some of the problems encountered in the prediction of gust loads for airplanes incorporating swept wings. The results indicate that within the scope of the data and the values of gradient distance investigated, the maximum acceleration increment depends on the slope of the lift curve of an equivalent straight wing multiplied by the cosine of the angle of sweep and on the effect of gradual penetration of the sweptback wing into the gust.
Date: January 1949
Creator: Reisert, Thomas D.
System: The UNT Digital Library
Application of Radial-Equilibrium Condition to Axial-Flow Compressor and Turbine Design (open access)

Application of Radial-Equilibrium Condition to Axial-Flow Compressor and Turbine Design

Note presenting some of the basic general equations governing the three-dimensional compressible flow of gas through a compressor or a turbine in terms of velocity components, total enthalpy, and entropy. The equations are applied to investigate the maximum compatible number of the radial variations of the gas properties between successive blade rows that a designer is free to specify.
Date: January 1949
Creator: Wu, Chung-Hua & Wolfenstein, Lincoln
System: The UNT Digital Library
Effect of hull length-beam ratio on the hydrodynamic characteristics of flying boats in waves (open access)

Effect of hull length-beam ratio on the hydrodynamic characteristics of flying boats in waves

Report presenting an investigation of the take-off and landing behavior in waves of models of a hypothetical flying boat with hull length-beam ratios of 6 and 15. The flying boat had a design gross weight of 75,000 pounds, a wing loading of 41.1 pounds per square foot, and a power loading of 11.5 pounds per brake horsepower for take-off. Results regarding the landing behavior, spray characteristics, and taxiing and take-off behavior are provided.
Date: January 1949
Creator: Carter, Arthur W.
System: The UNT Digital Library
Flight Investigation in Climb and at High Speed of a Two-Blade and a Three-Blade Propeller (open access)

Flight Investigation in Climb and at High Speed of a Two-Blade and a Three-Blade Propeller

Note presenting an investigation of a two-blade and a three-blade propeller on a slender-nose fighter airplane in climb and at high speed.
Date: January 1949
Creator: Hammack, Jerome B.
System: The UNT Digital Library
Comparison of the structural efficiency of panels having straight-web and curved-web Y-section stiffeners (open access)

Comparison of the structural efficiency of panels having straight-web and curved-web Y-section stiffeners

Report presenting comparisons of the structural efficiency of panels with straight-web and curved-web Y-section stiffeners. In the high-stress region in which failure is at least in part associated with local buckling, panels with curved-web Y-section stiffeners have higher structural efficiencies than panels with straight-web Y-section stiffeners, which is evidenced by higher average stresses at failure, smaller stiffener heights, or wider average spacing of rivet lines.
Date: January 1949
Creator: Dow, Norris F. & Hickman, William A.
System: The UNT Digital Library
Effects of Partial Admission on Performance of a Gas Turbine (open access)

Effects of Partial Admission on Performance of a Gas Turbine

Report presenting an investigation of the effect of partial admission of the driving fluid on the performance of a representative full-admission, production-type gas turbine. Results regarding losses, full-admission performance, partial-admission performance, partial admission as a means of power control, and a comparison of partial admission with other methods of power control are provided.
Date: February 1949
Creator: Kohl, Robert C.; Herzig, Howard Z. & Whitney, Warren J.
System: The UNT Digital Library
Method for Evaluating From Shadow or Schlieren Photographs the Pressure Drag in Two-Dimensional or Axially Symmetrical Flow Phenomena With Detached Shock (open access)

Method for Evaluating From Shadow or Schlieren Photographs the Pressure Drag in Two-Dimensional or Axially Symmetrical Flow Phenomena With Detached Shock

"A method has been developed for evaluating from shadow or schileren photographs the pressure drag of axially symmetrical bodies at zero angle of attack or of two-dimensional bodies producing detached shock. The method consists in the determination of the flow properties along a characteristic line and the application of the momentum theorem to a stream tube around the body. The method can be applied to the determination of external drag of supersonic inlets with subsonic flow at the entrance of the inlet" (p. 1).
Date: February 1949
Creator: Ferri, Antonio
System: The UNT Digital Library
Comparison between predicted and observed performance of gas-turbine stator blade designed for free-vortex flow (open access)

Comparison between predicted and observed performance of gas-turbine stator blade designed for free-vortex flow

Report presenting a comparison between the calculated design performance of a gas-turbine stator blade and its performance in a sector of an annular cascade tunnel. The gas velocities on the blade surface were computed by the stress filament method and compared with experimental values, with which they agreed satisfactorily. Results regarding discharge angle, vane-surface-velocity distribution, tangential- and axial-velocity distribution, and radial-equilibrium consideration are provided.
Date: April 1949
Creator: Huppert, M. C. & MacGregor, Charles
System: The UNT Digital Library
The application of airfoil studies to helicopter rotor design (open access)

The application of airfoil studies to helicopter rotor design

From Summary: "In order to facilitate the application of miscellaneous airfoil data to the problems of the helicopter designer, a discussion of a number of the problems most frequently arising is presented. A reference list of published papers on airfoil section characteristics (or their application) which experience has shown to be useful in connection with these helicopter problems is included."
Date: February 1949
Creator: Gustafson, F. B.
System: The UNT Digital Library
A study of flow changes associated with airfoil section drag rise at supercritical speeds (open access)

A study of flow changes associated with airfoil section drag rise at supercritical speeds

Report presenting a study of experimental pressure distributions and section characteristics for several moderately thick airfoil sections were made. The pressure distributions and section force characteristics of several moderately thick airfoil sections at Mach numbers above the drag-divergence Mach numbers were analyzed.
Date: February 1949
Creator: Nitzberg, Gerald E. & Crandall, Stewart
System: The UNT Digital Library
Effects of Several Design Variables on Turbine-Wheel Weight (open access)

Effects of Several Design Variables on Turbine-Wheel Weight

Report presenting an analysis showing the effect of several design variables on turbine-wheel flight. Equations are developed for the calculations of weights of the disk, the rim, and the blades, and use the following variables: the blading aspect ratio and solidity, the ratio of the centrifugal stress at the blade roots to that in the disk, and the ratio of wheel diameter at the blade root to wheel diameter at the blade tip.
Date: February 1949
Creator: LaValle, Vincent L. & Huppert, Merle C.
System: The UNT Digital Library
On Compressibility Corrections for Subsonic Flow Over Bodies of Revolution (open access)

On Compressibility Corrections for Subsonic Flow Over Bodies of Revolution

"A study of the subsonic flow past an infinitely long corrugated circular cylinder is presented to show the relation between two-dimensional and axisymmetrical flow. In fact, a solution is obtained which contains as limiting cases both the Prandtl-Glauert correction for two-dimensional flow and the Göthert correction for flow past slender bodies of revolution. Included in the paper are velocity-correction formulas for a cylinder with a single bump and for a corrugated cylinder in the presence of walls" (p. 1).
Date: February 1949
Creator: Reissner, Eric
System: The UNT Digital Library