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Minimum-drag ducted and pointed bodies of revolution based on linearized supersonic theory (open access)

Minimum-drag ducted and pointed bodies of revolution based on linearized supersonic theory

The linearized drag integral for bodies of revolution at supersonic speeds is presented in a double-integral form which is not based on slender-body approximations but which reduces to the equal slender-body expression in the proper limit. With the aid of a suitably chosen auxiliary condition, the minimum-external-wave-drag problem is solved for a transition section connecting two semi-infinite cylinders. The projectile tip is a special case and is compared with the Von Karman projectile tip. Calculations are presented which indicate that the method of analysis gives good first-order results in the moderate supersonic range.
Date: March 1, 1954
Creator: Parker, Hermon M.
System: The UNT Digital Library
A study of the zero-lift drag-rise characteristics of wing-body combinations near the speed of sound (open access)

A study of the zero-lift drag-rise characteristics of wing-body combinations near the speed of sound

"Comparisons have been made of the shock phenomena and drag-rise increments for representative wing and central-body combinations with those for bodies of revolution having the same axial developments of cross-sectional areas normal to the airstream. On the basis of these comparisons, it is concluded that near the speed of sound the zero-lift drag rise of a low-aspect-ratio thin-wing and body combination is primarily dependent on the axial development of the cross-sectional areas normal to the airstream. It follows that the drag rise for any such configuration is approximately the same as that for any other with the same development of cross-sectional areas" (p. 519).
Date: August 1, 1952
Creator: Whitcomb, Richard T.
System: The UNT Digital Library
Performance of NACA eight-stage axial-flow compressor designed on the basis of airfoil theory (open access)

Performance of NACA eight-stage axial-flow compressor designed on the basis of airfoil theory

"The NACA has conducted an investigation to determine the performance that can be obtained from a multistage axial-flow compressor based on airfoil research. A theory was developed; an eight-stage axial-flow compressor was designed, constructed, and tested. The performance of the compressor was determined for speeds from 5000 to 14,000 r.p.m with varying air flow at each speed" (p. 81).
Date: August 1, 1944
Creator: Sinnette, John T., Jr.; Schey, Oscar W. & King, J. Austin
System: The UNT Digital Library
The Effect of Increased Cooling Surface on Performance of Aircraft-Engine Cylinders as Shown by Tests of the NACA Cylinder (open access)

The Effect of Increased Cooling Surface on Performance of Aircraft-Engine Cylinders as Shown by Tests of the NACA Cylinder

A method of constructing fins of nearly optimum proportions has been developed by the NACA to the point where a cylinder has been manufactured and tested. Data were obtained on cylinder temperature for a wide range of inlet-manifold pressures, engine speeds, and cooling-pressure differences. The results indicate that an improvement of 40 percent in the outside-wall heat-transfer coefficient could be realized on the present NACA cylinder by providing a thermal bond equivalent to that of an integral fin-cylinder wall combination between the preformed fins and the cast cylinder wall" (p. 107).
Date: July 1, 1944
Creator: Schey, Oscar W.; Rollin, Vern G. & Ellerbrock, Herman H., Jr.
System: The UNT Digital Library
Compressibility and Heating Effects on Pressure Loss and Cooling of a Baffled Cylinder Barrel (open access)

Compressibility and Heating Effects on Pressure Loss and Cooling of a Baffled Cylinder Barrel

"Theoretical investigations have shown that, because air is compressible, the pressure-drop requirements for cooling an air-cooled engine will be much greater at high altitudes and high speeds than at sea level and low speeds. Tests were conducted by the NACA to obtain some experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. The results reported in the present paper are regarded as preliminary to tests on single-cylinder and multicylinder engines. Tests were conducted over a wide range of air flows and density altitudes" (p. 1).
Date: July 1, 1944
Creator: Goldstein, Arthur W. & Ellerbrock, Herman H., Jr.
System: The UNT Digital Library
Preignition-limited performance of several fuels (open access)

Preignition-limited performance of several fuels

Preignition-limited performance data were obtained on a supercharged CFR engine at two sets of operating conditions over a wide range of fuel-air ratios to determine the preignition characteristics for the following five fuels: s-3 reference fuel, s-3 plus 4 ml. tel per gallon, afd-33(140-p), benzene, and diisobutylene. Maximum thermal-plug temperatures at constant intake-air pressures were also determined to correlate the preignition characteristics of each fuel with its ability to increase general engine-temperature levels. Additional runs were made to compare the preignition-limited performance of triptane, triptane plus 4 ml. tel per gallon, and an-f-28r fuel.
Date: October 1, 1944
Creator: Male, Donald W. & Evvard, John C.
System: The UNT Digital Library
Knock-limited performance of several internal coolants (open access)

Knock-limited performance of several internal coolants

The effect of internal cooling on the knock-limited performance of an-f-28 fuel was investigated in a CFR engine, and the following internal coolants were used: (1) water, (2), methyl alcohol-water mixture, (3) ammonia-methyl alcohol-water mixture, (4) monomethylamine-water mixture, (5) dimethylamine-water mixture, and (6) trimethylamine-water mixture. Tests were run at inlet-air temperatures of 150 degrees and 250 degrees F. to indicate the temperature sensitivity of the internal-coolant solutions.
Date: February 1, 1944
Creator: Bellman, Donald R. & Evvard, John C.
System: The UNT Digital Library
Nitrited-Steel Piston Rings for Engines of High Specific Power (open access)

Nitrited-Steel Piston Rings for Engines of High Specific Power

"Several designs of nitrided-steel piston rings were performance-tested under variable conditions of output. The necessity of good surface finish and conformity of the ring to the bore was indicated in the preliminary tests. Nitrided-steel rings of the same dimensions as cast-iron rings operating on the original piston were unsatisfactory, and the final design was a lighter, rectangular, thin-face-width ring used on a piston having a maximum cross-head area and a revised skirt shape. Results were obtained from single-cylinder and multicylinder engine runs" (p. 1).
Date: April 1, 1944
Creator: Collins, John H., Jr.; Bisson, Edmond E. & Schmiedlin, Ralph F.
System: The UNT Digital Library
Air-Consumption Parameters for Automatic Mixture Control of Aircraft Engines (open access)

Air-Consumption Parameters for Automatic Mixture Control of Aircraft Engines

From Introduction: "The purpose of this analysis was to investigate the use of a function of intake-manifold pressure, exhaust back pressure, intake manifold temperature, and engine speed in place of a venturi as a means of measuring engine air consumption and to determine if this function is suitable for automatic mixture control."
Date: September 1, 1944
Creator: Shames, Sidney J.
System: The UNT Digital Library
An experimental investigation of rectangular exhaust-gas ejectors applicable for engine cooling (open access)

An experimental investigation of rectangular exhaust-gas ejectors applicable for engine cooling

"An experimental investigation of rectangular exhaust-gas ejector pumps was conducted to provide data that would serve as a guide to the design of ejector applications for aircraft engines with marginal cooling. The pumping characteristics of rectangular ejectors actuated by the exhaust of a single-cylinder aircraft engine were determined for a range of ejector mixing-section area from 20 to 50 square inches, over-all length from 12 to 42 inches, aspect ratio from 1 to 5, diffusing exit area from 20 to 81 square inches, and exhaust-nozzle aspect ratio from 1 to 42" (p. 161).
Date: May 1, 1944
Creator: Manganiello, Eugene J. & Bogatsky, Donald
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

"Basic general equations governing the three-dimensional compressible flow of gas through a compressor or turbine are given in terms of total enthalpy, entropy, and velocity components of the gas. Two methods of solution are obtained for the simplified, steady axially symmetric flow; one involves the use of a number of successive planes normal to the axis of the machine and short distances apart, and the other involves only three stations for a stage in which an appropriate radial-flow path is used. Methods of calculation for the limiting cases of zero and infinite blade aspect ratios and an approximate method of calculation for finite blade aspect ratio are also given" (p. 1).
Date: January 1, 1949
Creator: Wu, Chung-Hua & Wolfenstein, Lincoln
System: The UNT Digital Library
Equations for the Design of Two-Dimensional Supersonic Nozzles (open access)

Equations for the Design of Two-Dimensional Supersonic Nozzles

"Equations are presented for obtaining the wall coordinates of two-dimensional supersonic nozzles. The equations are based on the application of the method of characteristics to irrotational flow of perfect gases in channels. Curves and tables are included for obtaining the parameters required by the equations for the wall coordinates. A brief discussion of characteristics as applied to nozzle design is given to assist in understanding and using the nozzle-design method of this report. A sample design is shown" (p. 1).
Date: June 1, 1948
Creator: Pinkel, I. Irving
System: The UNT Digital Library
A Thermodynamic Study of the Turbojet Engine (open access)

A Thermodynamic Study of the Turbojet Engine

"Charts are presented for computing thrust, fuel consumption, and other performance values of a turbojet engine for any given set of operating conditions and component efficiencies. The effects of pressure losses in the inlet duct and the combustion chamber, of variation in physical properties of the gas as it passes through the system, of reheating of the gas due to turbine losses, and of change in mass flow by the addition of fuel are included. The principle performance chart shows the effects of primary variables and correction charts provide the effects of secondary variables and of turbine-loss reheat on the performance of the system" (p. 599).
Date: June 1, 1946
Creator: Pinkel, Benjamin & Karp, Irving M.
System: The UNT Digital Library
Velocity distributions on two-dimensional wing-duct inlets by conformal mapping (open access)

Velocity distributions on two-dimensional wing-duct inlets by conformal mapping

The conformal-mapping method of the Cartesian mapping function is applied to the determination of the velocity distribution on arbitrary two-dimensional duct-inlet shapes such as are used in wing installations. An idealized form of the actual wing-duct inlet is analyzed. The effects of leading edge stagger, inlet-velocity ratio, and section lift coefficients on the velocity distribution are included in the analysis. Numerical examples are given and, in part, compared with experimental data.
Date: April 1, 1947
Creator: Perl, W. & Moses, H. E.
System: The UNT Digital Library
Calculations of Economy of 18-Cylinder Radial Aircraft Engine With Exhaust-Gas Turbine Geared to the Crankshaft (open access)

Calculations of Economy of 18-Cylinder Radial Aircraft Engine With Exhaust-Gas Turbine Geared to the Crankshaft

Calculations based on dynamometer test-stand data obtained on an 18-cylinder radial engine were made to determine the improvement in fuel consumption that can be obtained at various altitudes by gearing an exhaust-gas turbine to the engine crankshaft in order to increase the engine-shaft work.
Date: January 1, 1945
Creator: Hannum, Richard W. & Zimmerman, Richard H.
System: The UNT Digital Library
Analysis of wind-tunnel stability and control tests in terms of flying qualities of full-scale airplanes (open access)

Analysis of wind-tunnel stability and control tests in terms of flying qualities of full-scale airplanes

From Introduction: "The purpose of this paper is to outline a suggested form of presentation of the results of a stability and control investigation in terms of flying qualities as defined in reference 1 and to systematize and review briefly the analytical work required for this type of presentation. No effort is made to specify definite test procedures."
Date: April 1, 1943
Creator: Kayten, Gerald G.
System: The UNT Digital Library
Quantitative Treatment of the Creep of Metals by Dislocation and Rate-Process Theories (open access)

Quantitative Treatment of the Creep of Metals by Dislocation and Rate-Process Theories

"An equation for the steady-state rate of creep has been derived by applying the theory of dislocations to the creep of pure metals. The form of this equation is in agreement with empirical equations describing creep rates. The theory was also used to predict the dependence of steady-state rate of creep on physical constants of the material and good agreement was obtained with data in the literature for pure annealed metals" (p. 169).
Date: January 1, 1946
Creator: Nowick, A. S. & Machlin, E. S.
System: The UNT Digital Library
A visual photographic study of cylinder lubrication (open access)

A visual photographic study of cylinder lubrication

From Summary: "A V-type engine provided with a glass cylinder was used to study visually the lubrication characteristics of an aircraft-type piston. Photographs and data were obtained with the engine motored at engine speeds up to 1000 r.p.m. and constant cylinder-head pressures of 0 and 50 pounds per square inch. A study was made of the orientation of the piston under various operating conditions, which indicated that the piston was inclined with the crown nearest the major-thrust cylinder face throughout the greater part of the cycle. The piston moved laterally in the cylinder under the influence of piston side thrust."
Date: August 1, 1945
Creator: Shaw, Milton C. & Nussdorfer, Theodore
System: The UNT Digital Library
Cylinder-Temperature Correlation of a Single-Cylinder Liquid-Cooled Engine (open access)

Cylinder-Temperature Correlation of a Single-Cylinder Liquid-Cooled Engine

"An analysis based on nonboiling forced-convection heat-transfer theory is made of the cooling processes in liquid-cooled engine cylinders. Semiempirical equations that relate the average head and barrel temperatures with the primary engine and coolant parameters are derived. A correlation method based on these equations is applied to data obtained from previously reported investigations, which were conducted over large ranges of engine and coolant conditions with two liquid-cooled cylinders using water and various aqueous ethylene glycol solutions as coolants" (p. 285)
Date: October 1, 1946
Creator: Pinkel, Benjamin; Manganiello, Eugene J. & Bernardo, Everett
System: The UNT Digital Library
An Analysis of the Full-Floating Journal Bearing (open access)

An Analysis of the Full-Floating Journal Bearing

Report discussing an analysis of the operating characteristics of a full-floating journal bearing, a bearing in which a floating sleeve is located between the journal and bearing surfaces, is presented together with charts from which the performance of such bearings may be predicted.
Date: January 1, 1947
Creator: Shaw, M. C. & Nussdorfer, T. J., Jr.
System: The UNT Digital Library
Some Effects of Compressibility on the Flow Through Fans and Turbines (open access)

Some Effects of Compressibility on the Flow Through Fans and Turbines

"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.
System: The UNT Digital Library
The Measurement of Fuel-Air Ratio by Analysis of the Oxidized Exhaust Gas (open access)

The Measurement of Fuel-Air Ratio by Analysis of the Oxidized Exhaust Gas

"An investigation was made to determine a method of measuring fuel-air ratio that could be used for test purposes in flight and for checking conventional equipment in the laboratory. Two single-cylinder test engines equipped with typical commercial engine cylinders were used. The fuel-air ratio of the mixture delivered to the engines was determined by direct measurement of the quantity of air and of fuel supplied and also by analysis of the oxidized exhaust gas and of the normal exhaust gas" (p. 73).
Date: October 1, 1943
Creator: Gerrish, Harold C. & Meem, J. Lawrence, Jr.
System: The UNT Digital Library
Direct Measurements of Skin Friction (open access)

Direct Measurements of Skin Friction

"A device has been developed to measure local skin friction on a flat plate by measuring the force exerted upon a very small movable part of the surface of the flat plate. These forces, which range from about 1 milligram to about 100 milligrams, are measured by means of a reactance device. The apparatus was first applied to measurements in the low-speed range, both for laminar and turbulent boundary layers. The device was then applied to high-speed subsonic flow and the turbulent-skin-friction coefficients were determined up to a Mach number of about 0.8" (p. 281).
Date: June 1, 1951
Creator: Dhawan, Satish
System: The UNT Digital Library
Investigation of Separation of the Turbulent Boundary Layer (open access)

Investigation of Separation of the Turbulent Boundary Layer

"An investigation was conducted on a turbulent boundary layer near a smooth surface with pressure gradients sufficient to cause flow separation. The Reynolds number was high, but the speeds were entirely within the incompressible flow range. The investigation consisted of measurements of mean flow, three components of turbulence intensity, turbulent shearing stress, and correlations between two fluctuation components at a point and between the same component of different points" (p. 1).
Date: June 1, 1949
Creator: Schubauer, G. B. & Klebanoff, P. S.
System: The UNT Digital Library