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The Flow About a Section of a Finite-Aspect-Ratio NACA 0018 Airfoil on a Transonic Bump

Description: Note presenting pressure distributions on a semispan rectangular wing model with an NACA 0015 airfoil section and a moderate aspect ratio at one spanwise station in tests made on a transonic bump in the 16-foot high-speed wind tunnel. The results indicated that at a fixed angle of attack, a region developed over the airfoil wherein the Mach number at each point remained essentially constant as the free-stream Mach number was increased above the critical.
Date: October 1953
Creator: Mellenthin, Jack A.
Partner: UNT Libraries Government Documents Department

An Investigation of a Lifting 10-Percent-Thick Symmetrical Double-Wedge Airfoil at Mach Number Up to 1

Description: Note presenting pressure measurements on the surface of a two-dimensional symmetrical double-wedge airfoil obtained from tests in the Langley 4- by 19-inch semiopen tunnel at lifting conditions and Mach numbers up to 1. The purpose of the investigation was to obtain normal-force, pressure-drag, and pitching-moment data and to compare them with available experimental and theoretical results.
Date: November 1954
Creator: Humphreys, Milton D.
Partner: UNT Libraries Government Documents Department

Exploratory Investigation of the Flow in the Separated Region Ahead of Two Blunt Bodies at Mach Number 2

Description: Memorandum presenting an investigation of flow separation from a flat plate ahead of two blunt two-dimensional bodies in detail at Mach number 2. Interferograms were obtained for the separated regions, and the pitot-pressure distribution and flow directions were surveyed in one of the regions. Results regarding recovery factors and static pressures, density, total pressure, Mach number distribution, and flow-direction survey are provided.
Date: June 30, 1955
Creator: Bernstein, Harry & Brunk, William E.
Partner: UNT Libraries Government Documents Department

High-Altitude Cooling 4: Intercoolers

Description: "The variation of intercooling requirements with altitude is discussed and the corresponding effects on intercooler design are shown. A discussion is also given of the relations among the various design parameters and of the ranges of choice in design. The important effects of the various factors on intercooler proportions are illustrated with charts for the Harrison copper cross-flow intercooler" (p. 1).
Date: September 1944
Creator: Rubert, K. F.
Partner: UNT Libraries Government Documents Department

Investigation of Variation in Base Pressure Over the Reynolds Number Range in Which Wake Transition Occurs for Nonlifting Bodies of Revolution at Mach Numbers From 1.62 to 2.62

Description: Note presenting an investigation to determine the Reynolds and Mach number effects on the base pressure of a nonlifting ogival body of revolution over the Reynolds number range in which wake transition occurs. The results were compared with previous base-pressure data and also with the qualitative theoretical predictions of Crocco and Lees.
Date: January 1957
Creator: Van Hise, Vernon
Partner: UNT Libraries Government Documents Department

The Measurement of Pressure Altitude on Aircraft

Description: Note presenting a determination of the accuracy with which pressure altitude can be measured by calculation of the errors in the measuring system, errors arising from operation of the system, and variations in atmospheric pressure. Some possibilities for reducing errors in the categories of altimeter-scale error, static-pressure error, atmospheric-reference error, flight technical error, friction error, and service error are provided.
Date: October 1957
Creator: Gracey, William
Partner: UNT Libraries Government Documents Department

Effect of Normal Pressure on the Critical Compressive Stress of Curved Sheet

Description: Results are presented of tests of two specimens tested to study the effect of normal pressure on the critical compressive stress for thin curved sheets. These specimens are designated by their respective rib spacings of 10 inches and 30 inches. The relationship between compressive stress and normal pressure at which buckles disappeared is independent of whether the buckles were made to disappear by increase of normal pressure or decrease of compressive stress. (author).
Date: August 25, 1942
Creator: Rafel, Norman
Partner: UNT Libraries Government Documents Department

Wind-Tunnel Investigation at a Mach Number of 2.01 of Forebody Strakes for Improving Directional Stability of Supersonic Aircraft

Description: Memorandum presenting an investigation in the 4- by 4-foot supersonic pressure tunnel to determine the effects of forebody strakes on the aerodynamic characteristics in sideslip of a delta-wing airplane model at Mach number of 2.01. The presence of the strakes increased the directional-stability level for both vertical-tail arrangements. Results of pressure tunnels for a forebody show that the presence of the strakes provides a stabilizing influence on the forebody which is consistent with the results of force tests.
Date: May 26, 1958
Creator: Driver, Cornelius
Partner: UNT Libraries Government Documents Department

The Response of Pressure Measuring Systems to Oscillating Pressures

Description: Note presenting a method for calculating the response and lag in pressure measuring systems subjected to steady-state sinusoidally varying pressures. The pressure system is assumed to consist of an inlet restriction, tubing length, and connected instrument volume. Results of the phase-shift determination are provided.
Date: February 1949
Creator: Taback, Israel
Partner: UNT Libraries Government Documents Department

A Miniature Electrical Pressure Gage Utilizing a Stretched Flat Diagram

Description: "A variable-air-gap, inductance-type, electrical pressure gage is described that is basically 7/16 inch in diameter and 1/4 inch in thickness. The gage was designed to measure accurately pressures fluctuating at high frequencies and has proved to be a value as a general-purpose electrical gage for aeronautical work where small size and minimum response to acceleration forces are important factors. Design equations and curves are presented which can be used to predict the deflections and fundamental natural frequencies of stretched flat diaphragms" (p. 1).
Date: April 1952
Creator: Patterson, John L.
Partner: UNT Libraries Government Documents Department

Investigation of Perforated Convergent-Divergent Diffusers With Initial Boundary Layer

Description: An experimental investigation was made at Mach number 1.90 of the performance of a series of perforated convergent-divergent supersonic diffusers operating with initial boundary layer, which was induced and controlled by lengths of cylindrical inlets affixed to the diffusers. Supercritical mass-flow and peak total-pressure recoveries were decreased slightly by use of the longest inlets (4 inlet diameters in length). Combinations of cylindrical inlets, perforated diffusers, and subsonic diffuser were evaluated as simulated wind tunnels having second throats. Comparisons with noncontracted configurations of similar scale indicated conservatively computed power reductions of 25 percent.
Date: August 15, 1950
Creator: Weinstein, Maynard I.
Partner: UNT Libraries Government Documents Department

Investigation of an Underslung Scoop Inlet at Mach Numbers to 1.99

Description: Memorandum presenting a study of the performance of a scoop-type inlet on the bottom of a body of revolution at a range of Mach numbers and angles of attack to 10 degrees. The investigation included a study of the effects of altering the approach surface ahead of the inlet, extending the boundary-layer splitter plate, and bleeding air at the throat and exit of the diffuser. Results regarding the flow survey ahead of the inlet, alternative configurations, internal-flow details of the basic configuration, air bleed at the throat, and air bypass at the engine face are provided.
Date: March 13, 1957
Creator: Weinstein, Maynard I.; Vargo, Donald J. & McKevitt, Frank
Partner: UNT Libraries Government Documents Department

Characteristics of a 40 Degree Cone for Measuring Mach Number, Total Pressure, and Flow Angles at Supersonic Speeds

Description: Note presenting an experimental investigation conducted to determine the characteristics of a 40 degree cone for use in the measurement of Mach number, total pressure, and flow angles. The cone had a total-pressure orifice at the apex and four equally spaced static-pressure orifices on the surface and pressure measurements were taken at a range of angles of pitch, Mach numbers, and Reynolds numbers. Results regarding cone pressure distribution, determination of Mach number, determination of total pressure, and determination of flow angles are provided.
Date: May 1957
Creator: Centolanzi, Frank J.
Partner: UNT Libraries Government Documents Department

Prediction of Downwash and Dynamic Pressure at the Tail From Free-Flight Measurements

Description: "The present measurements form a continuation of earlier flight tests published in a previous report for predicting the downwash at the tail of an airplane. The method makes use of the tail itself as integrating contact surface to the extent that, beginning from the measurement of the self-alignment of the elevator, the mean downwash angle and dynamic pressure at the tail are determined. The instrumental accuracy is considerably improved if the elevator is completely separate from the controls during the tests, because the effect of friction on the self-alignment of the elevator is then reduced to a minimum and a finer elevator weight balance is rendered possible" (p. 1).
Date: July 1942
Creator: Eujen, E.
Partner: UNT Libraries Government Documents Department

Travel of the Center of Pressure of Airfoils Transversely to the Air Stream

Description: The experiments here described were performed for the purpose of obtaining the essential facts concerning the distribution of the air force along the span. We did not follow, however, the time-consuming method of point-to-point measurements of the pressure distribution on the wing surfaces, but determined directly the moment of mean force about an axis passing through the middle of the span parallel to the direction of flight.
Date: September 1929
Creator: Katzmayr, Richard
Partner: UNT Libraries Government Documents Department

Pressure distribution over thick tapered airfoils, NACA 81, USA 27c modified and USA 35

Description: "At the request of the United States Army Air Service, the tests reported herein were conducted in the 5-foot atmospheric wind tunnel of the Langley Memorial Aeronautical Laboratory. The object was the measurement of pressures over three representative thick, tapered airfoils which are being used on existing or forthcoming army airplanes. The results are presented in the form of pressure maps, cross-plan load and normal force coefficient curves and load contours" (p. 433).
Date: 1926
Creator: Reid, Elliott G.
Partner: UNT Libraries Government Documents Department

The flow and force characteristics of supersonic airfoils at high subsonic speeds

Description: Report presenting an investigation at subsonic Mach numbers in the rectangular high-speed tunnel on five supersonic airfoils and, for comparison, on two subsonic airfoils. Two-dimensional data were obtained by pressure measurements and schileren photographs at angles of attack from 0 to 4 degrees for a range of Mach numbers between 0.30 and 0.90. Results regarding pressure distributions, normal-force coefficients, pitching-moment of normal-force about the quarter-chord point, drag coefficient, and unusual flow at high Mach numbers are provided.
Date: March 1947
Creator: Lindsey, W. F.; Daley, Bernard N. & Humphreys, Milton D.
Partner: UNT Libraries Government Documents Department

Preliminary experimental investigation of low-speed turbulent boundary layers in adverse pressure gradients

Description: Report presenting measurements of velocity profiles and skin friction in subsonic turbulent boundary layers with adverse pressure gradients. The skin friction in an adverse pressure gradient was found to decrease steadily with distance to a value approaching zero for the region of separation. Results regarding the mean velocity distribution and separation, comparison of experimental values with semiempirical relations, and wall shearing stress are provided.
Date: October 1953
Creator: Sandborn, Virgil A.
Partner: UNT Libraries Government Documents Department

Study of the momentum distribution of turbulent boundary layers in adverse pressure gradients

Description: Report presenting the evaluation and analysis of the mean and turbulent terms of the equations of motion and the stress tensor at four stations in a turbulent boundary layer with a progressively increasing adverse pressure gradient. Report presenting mean flow parameters, summary of velocity measurements, evaluation of wall shearing stress, shear stress distribution across boundary layer, and stress tensor are provided.
Date: January 1955
Creator: Sandborn, Virgil A. & Slogar, Raymond J.
Partner: UNT Libraries Government Documents Department

Nonmetallic diaphragms for instruments

Description: "This report, the second of a series of reports relating to the general subject of instrument diaphragms. The first report of the series was published as Technical Report no. 165, "diaphragms for aeronautic instruments," and comprised an outline of historical developments and theoretical principles. The present report relates entirely to nonmetallic diaphragms, the use of which in certain types of pressure elements has been increasing for some time" (p. 423).
Date: 1925
Creator: Eaton, H. N. & Buckingham, C. T.
Partner: UNT Libraries Government Documents Department

Some Effects of Compressibility on the Flow Through Fans and Turbines

Description: "The laws of conservation of mass, momentum, and energy are applied to the compressible flow through a two-dimensional cascade of airfoils. A fundamental relation between the ultimate upstream and downstream flow angles, the inlet Mach number, and the pressure ratio across the cascade is derived. Comparison with the corresponding relation for incompressible flow shows large differences. The fundamental relation reveals two ranges of flow angles and inlet Mach numbers, for which no ideal pressure ratio exists" (p. 123).
Date: August 1, 1945
Creator: Perl, W. & Epstein, H. T.
Partner: UNT Libraries Government Documents Department