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Some Recent Contributions to the Study of Transition and Turbulent Boundary Layers

Description: Report presenting a paper in two parts about transition and turbulent boundary layers. The first part reviews the current problem of the instability of laminar boundary layers. The second part reviews the current state of knowledge of the mechanics of turbulent boundary layers and of the methods now being used for fundamental studies of the turbulent fluctuations in turbulent boundary layers.
Date: April 1947
Creator: Dryden, Hugh L.
Partner: UNT Libraries Government Documents Department

Considerations of the Total Drag of Supersonic Airfoil Sections

Description: The results of calculations of the viscous and pressure drags of some two-dimensional supersonic airfoils at zero lift are presented. The results indicate that inclusion of viscous drag alters many previous results regarding the desirability of certain airfoil shapes for securing low drags at supersonic speeds. At certain Reynolds and Mach numbers, for instance, a circular-arc airfoil may theoretically have less drag than the previously advocated symmetrical wedge-shape profile; although under different conditions, the circular-arc airfoil may have a higher drag.
Date: July 1947
Creator: Ivey, H. Reese & Klunker, E. Bernard
Partner: UNT Libraries Government Documents Department

Two-Dimensional Irrotational Transonic Flows of a Compressible Fluid

Description: 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
Partner: UNT Libraries Government Documents Department

Tables and charts of flow parameters across oblique shocks

Description: Shock-wave equations have been evaluated for a range of Mach number in front of the shock from 1.05 to 4.0. Mach number behind the shock, pressure ratio, derivation of flow, and angle of shock are presented on charts. Values are also included for density ratio and change in entropy.
Date: August 1948
Creator: Neice, Mary M.
Partner: UNT Libraries Government Documents Department

Two-dimensional subsonic compressible flows past arbitrary bodies by the variational method

Description: Instead of solving the nonlinear differential equation which governs the compressible flow, an approximate method of solution by means of the variational method is used. The general problem of steady irrotational flow past an arbitrary body is formulated. Two examples were carried out, namely, the flow past a circular cylinder and the flow past a thin curved surface. The variational method yields results of velocity and pressure distributions which compare excellently with those found by existing methods. These results indicate that the variational method will yield good approximate solution for flow past both thick and thin bodies at both high and low Mach numbers.
Date: March 1951
Creator: Wang, Chi-Teh
Partner: UNT Libraries Government Documents Department

Performance of B. M. W. 185-horsepower airplane engine

Description: Report discusses the results of testing on a B.M.W. engine in an altitude chamber where temperature and pressure can be controlled to simulate flight at various altitudes. Results for various engine speeds, altitudes, and propeller speeds are provided.
Date: April 13, 1922
Creator: Sparrow, Stanwood Willston
Partner: UNT Libraries Government Documents Department

Tables for the Computation of Wave Drag of Arrow Wings of Arbitrary Airfoil Section

Description: 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, Fredrick C. & Cooper, Morton
Partner: UNT Libraries Government Documents Department

Average Outside-Surface Heat-Transfer Coefficients and Velocity Distributions for Heated and Cooled Impulse Turbine Blades in Static Cascades

Description: Heat-transfer investigation conducted on cooled as well heated impulse-type turbine blades in a static cascade to determine the effect of direction of heat flow on convective heat-transfer coefficients.
Date: March 9, 1951
Creator: Hubbartt, James E. & Schum, Eugene F.
Partner: UNT Libraries Government Documents Department

Charts for the Computation of Equilibrium Composition of Chemical Reactions in the Carbon-Hydrogen-Nitrogen System at Temperatures from 2000 to 5000 Degrees K

Description: Charts are provided for the estimation and progressive adjustment of two independent variables on which the calculations are based. Additional charts are provided for the graphical calculation of the composition.
Date: July 1948
Creator: Huff, Vearl N. & Calvert, Clyde S.
Partner: UNT Libraries Government Documents Department

Flight Tests of Modifications to Improve the Aileron Control Characteristics of a North American XP-51 Airplane (AC No. 41-38)

Description: Investigations were undertaken to improve the ailerons of a P-51 fighter so as to obtain greater effectiveness without increasing the stick forces. Modifications consisted of increasing the deflection range of the aileron to 70 percent and changing the original concave section to a thick section with beveled trailing edge. Results of the modified ailerons showed an increase in effectiveness over the original aileron of 70 percent at low speed and 55 percent at high speeds.
Date: June 1942
Creator: White, M. D. & Hoover, Herbert H.
Partner: UNT Libraries Government Documents Department

The effect of exhaust-stack shape on the design and performance of the individual cylinder exhaust-gas jet-propulsion system

Description: Report presenting tests on a single-cylinder, air-cooled engine to determine the effect of several different exhaust-stack shapes on the design and performance of the individual cylinder exhaust-gas jet-propulsion systems. Results regarding the effect of nozzle area and stack shape on exhaust-gas jet thrust, effect of nozzle area and stack shape on overall performance for the S-shape, the 90 degree bend, and the 180 degree bend, the effect on the shape on engine power and volumetric efficiency, and the effect of a branched stack on engine power are provided.
Date: November 1942
Creator: Turner, L. Richard & Humble, Leroy V.
Partner: UNT Libraries Government Documents Department

The effect of cowling on cylinder temperatures and performance of a Wright J-5 engine

Description: This report presents the results of tests conducted to determine the effect of different amounts and kinds of cowling on the performance and cylinder temperatures of a standard Wright J-5 engine. These tests were conducted in conjunction with drag and propeller tests in which the same cowlings were used. Four different cowlings were investigated varying from the one extreme of no cowling on the engine to the other extreme of the engine completely cowled and the cooling air flowing inside the cowling through an opening in the nose and out through an annular opening at the rear of the engine. Each cowling was tested at air speeds of approximately 60, 80, and 100 miles per hour.
Date: May 2, 1929
Creator: Schey, Oscar W. & Biermann, Arnold E.
Partner: UNT Libraries Government Documents Department

Analysis of circular shell-supported frames

Description: From Summary: "This paper deals with the single problem of circular shell-supported frames subjected to concentrated loadings. A mathematical attack is developed and presented in the form of nondimensional-coefficient curves."
Date: May 1944
Creator: Wignot, J. E.; Combs, Henry & Ensrud, A. F.
Partner: UNT Libraries Government Documents Department

The problem of longitudinal stability and control at high speeds

Description: Report discussing the difficulty in pulling of high-speed dives, which is primarily due to the effect of compressibility on the lift of the wing. Some of the means described for providing increased longitudinal control include auxiliary flaps and a controllable stabilizer.
Date: November 1943
Creator: Hood, Manley J. & Allen, H. Julian
Partner: UNT Libraries Government Documents Department

Supplies and production of aircraft woods

Description: The purpose of this report is to present in brief form such information as is available regarding the supplies of the kinds of wood that have been used or seem likely to become important in the construction of airplanes, and the amount of lumber of each species normally put on the market each year. A general statement is given of the uses to which each kind of wood is or may be put.
Date: 1920
Creator: Sparhawk, W. N.
Partner: UNT Libraries Government Documents Department

Tests of a thermal ice-prevention system for a wing leading-edge landing-light installation

Description: Report discussing the creation of a thermal ice-prevention system of a bomber-type airplane to provide protection against ice and fog formations on the transparent fairing over the landing light in the wing leading edge. A comparison between the design performance and actual performance showed that the outer-surface heat-transfer coefficient was correctly predicted, but the inner-surface heat-transfer coefficient was four times as large, leading to failure of the plastic fairing.
Date: December 1944
Creator: Hillendahl, Wesley H.
Partner: UNT Libraries Government Documents Department

Intercooler cooling-air weight flow and pressure drop for minimum drag loss

Description: Report presenting an analysis of the power losses in airplane flight of cross-flow plate and tubular intercoolers to determine the cooling-air weight flow and pressure drop that give minimum total power loss for any given cooling effectiveness. The investigation covers a range of flight conditions of altitude, airspeed, lift-drag ratio, supercharger-pressure ratio, and adiabatic efficiency.
Date: April 1944
Creator: Reuter, J. George & Valerino, Michael F.
Partner: UNT Libraries Government Documents Department

An approximate spin design criterion for monoplanes

Description: "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.
Partner: UNT Libraries Government Documents Department

Flight tests of thermal ice-prevention equipment in the XB-24F airplane

Description: Report presenting performance tests of thermal ice-prevention equipment designed and installed in the XB-24F airplane in icing and non-icing conditions. The recorded temperature and air-flow data, and the calculated quantities of heat flow throughout the system are presented in tabular form.
Date: October 7, 1943
Creator: Neel, Carr B. & Jones, Alun R.
Partner: UNT Libraries Government Documents Department

Wall interference in a two-dimensional-flow wind tunnel with consideration of the effect of compressibility

Description: Report presenting tunnel-wall corrections for an airfoil of finite thickness and camber in a two-dimensional-flow wind tunnel. The theory takes account of the effects of the wake of the airfoil and of the compressibility of the fluid and is based on the assumption that the chord of the airfoil is small in comparison with the height of the tunnel. The theoretical results are compared with the small amount of low-speed experimental data available and agreement is seen to be satisfactory, even for relatively large values of the chord-height ratio.
Date: December 1944
Creator: Allen, H. Julian & Vincenti, Walter G.
Partner: UNT Libraries Government Documents Department