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Engines and propellers for powered gliders and light airplanes

Description: The object of the present paper is to consider the interaction of engine, propeller, and airplane for the low-power range. The discussion is presented in a form so as to provide the engine builder with a basis in his selection in the type of engine required, a suitable selection being possible only in connection with considerations on the best possible propeller.
Date: March 1, 1938
Creator: Gropp, H
Partner: UNT Libraries Government Documents Department

Engine and inspection tests of methyl tert-butyl ether as a component of aviation fuel

Description: Report presenting an investigation of the suitability of methyl tert-butyl ether as a component of aviation fuel from considerations of knock-limited performance tests and laboratory inspection tests. Data were obtained from testing on the 17.6 engine under supercharged conditions with fuel blends containing 10 and 20 percent methyl tert-butyl ether. Results regarding small-scale-engine data, full-scale-engine data, and inspection data are provided.
Date: August 1944
Creator: Barnett, Henry C.; Meyer, Carl L. & Jones, Anthony W.
Partner: UNT Libraries Government Documents Department

Equations and charts for the rapid estimation of hinge-moment and effectiveness parameters for trailing-edge controls having leading and trailing edges swept ahead of the Mach lines

Description: Existing conical-flow solutions have been used to calculate the hinge-moments and effectiveness parameters of trailing-edge controls having leading and trailing edges swept ahead of the Mach lines and having streamwise root and tip chords. Equations and detailed charts are presented for the rapid estimation of these parameters. Also included is an approximate method by which these parameters may be corrected for airfoil-section thickness.
Date: January 1, 1951
Creator: Goin, Kennith L
Partner: UNT Libraries Government Documents Department

Equilibrium operating performance of axial-flow turbojet engines by means of idealized analysis

Description: A method of predicting equilibrium operating performance of turbojet engines has been developed, with the assumption of simple model processes for the components. Results of the analysis are plotted in terms of dimensionless parameters comprising critical engine dimensions and over-all operating variables. This investigation was made of an engine in which the ratio of axial inlet-air velocity to compressor-tip velocity is constant, which approximates turbojet engines with axial-flow compressors. Experimental correlation of the theory with data from several existing axial-flow-type engines was good and showed close correlation between calculated and measured performance.
Date: January 1, 1950
Creator: Sanders, John C & Chapin, Edward C
Partner: UNT Libraries Government Documents Department

Experimental investigation of aircraft propellers exposed to oblique air currents

Description: Two screw propellers, a normal airplane propeller with a pitch/diameter ratio H/D = 0.5 and a helicopter propeller H/D = 0.2 were tested in the large wind tunnel of the Gottigen Aerodynamic Institute. With both propellers the angle between the propeller axis and the direction of the wind was varied from 0 to 90 degrees. In addition to the three force and the three moment components in a wind-fast coordinate system, the corresponding components in a propeller-fast coordinate system, a total of six force and six moment components, together with the propulsive efficiency, were measured or calculated from measurements. The results are given in the form of diagrams and briefly discussed. The propeller models and method of experimentation are described and the symbols are defined.
Date: April 1, 1930
Creator: Flachsbart, O & Krober, G
Partner: UNT Libraries Government Documents Department

The enlarged N.A.C.A. tank, and some of its work

Description: The most conspicuous of the features of the enlarged N.A.C.A. tank are derived directly from those of the original tank and owe their present form not only to the reasons for their first use but also to the experience obtained with them. As in the original tank, there are: 1) A basin of great length (new 2,880 feet); 2) Rails made of structural H beams, without machining; 3) A towing carriage of very high speed (now 80 mph maximum); 4) Rubber tires on all the wheels, pneumatic on the running wheels and solid on the guide wheels.
Date: November 1, 1939
Creator: Truscott, Starr
Partner: UNT Libraries Government Documents Department

End-zone water injection as a means of suppressing knock in a spark-ignition engine

Description: Report discusses the results of an investigation into the effectiveness of water injection into the combustion end zone of a spark-ignition engine cylinder for the suppression of knock. The injection angle was found to be very important for obtaining maximum results. The results of various angles and amounts of water were examined.
Date: September 1944
Creator: Brun, Rinaldo J.; Olsen, H. Lowell & Miller, Cearcy D.
Partner: UNT Libraries Government Documents Department

Calculations on the forces and moments for an oscillating wing-aileron combination in two-dimensional potential flow at sonic speed

Description: From Summary: "The linearized theory for compressible unsteady flow is used, as suggested in recent contributions to the subject, to obtain the velocity potential and the lift and moment for a thin harmonically oscillating, two-dimensional wing-aileron combination moving at sonic speed. The velocity potential is derived by considering the sonic case as the limit of the linearized supersonic theory. From the velocity potential explicit expressions for the lift and moment are developed for vertical translation and pitching of the wing and rotation of the aileron. The sonic results are compared and found to be consistent with previously obtained subsonic and supersonic results. Several figures are presented showing the variation of lift and moment with reduced frequency and Mach number and the influence of Mach number on some cases of bending-torsion flutter."
Date: September 4, 1951
Creator: Nelson, Herbert C. & Berman, Julian H.
Partner: UNT Libraries Government Documents Department

Calculations of the Performance of a Compression-Ignition Engine-Compressor Turbine Combination I : Performance of a Highly Supercharged Compression-Ignition Engine

Description: Small high-speed single-cylinder compression-ignition engines were tested to determine their performance characteristics under high supercharging. Calculations were made on the energy available in the exhaust gas of the compression-ignition engines. The maximum power at any given maximum cylinder pressure was obtained when the compression pressure was equal to the maximum cylinder pressure. Constant-pressure combustion was found possible at an engine speed of 2200 rpm. Exhaust pressures and temperatures were determined from an analysis of indicator cards. The analysis showed that, at rich mixtures with the exhaust back pressure equal to the inlet-air pressure, there is excess energy available for driving a turbine over that required for supercharging. The presence of this excess energy indicates that a highly supercharged compression-ignition engine might be desirable as a compressor and combustion chamber for a turbine.
Date: December 1, 1945
Creator: Sanders, J. C. & Mendelson, Alexander
Partner: UNT Libraries Government Documents Department

The controls at low hinge moments

Description: A very stable airplane remains very maneuverable when the hinge moments of the controls remain inferior to those obtained with the conventional forms and when the wing lift at high angles has been improved. From this point of view, elevators balanced by recoil of the hinge, and slotted wings present some interesting features.
Date: September 1, 1932
Creator: Pris, M
Partner: UNT Libraries Government Documents Department

The conversion of energy in a radiator

Description: It was a worthwhile task to research methods to lower the cooling drag of radiators. And the success of these efforts has been so great that without this research the modern high-speed airplane would have decidedly inferior performance. It is the purpose of this report to give a comprehensive discussion of all the fundamental principles and phenomena that offer a key to understanding modern cooling problems.
Date: July 1938
Creator: Weise, A.
Partner: UNT Libraries Government Documents Department

Convection of a pattern of vorticity through a shock wave

Description: An arbitrary weak spatial distribution of vorticity can be represented in terms of plane sinusoidal shear waves of all orientations and wave lengths (Fourier integral). The analysis treats the passage of a single representative weak shear wave through a plane shock and shows refraction and modification of the shear wave with simultaneous generation of an acoustically intense sound wave. Applications to turbulence and to noise in supersonic wind tunnels are indicated.
Date: January 1, 1954
Creator: Ribner, H S
Partner: UNT Libraries Government Documents Department

Contribution to the mutual interference of wing and propeller

Description: The change of induced wing drag due to the field of flow of the propeller was analyzed quantitatively. The field of flow of the propeller is represented by a uniform distribution of sinks over the propeller disk area, whose strength is determined by the increase in speed in the slipstream. The superposition of this sink flow on the basic flow reproduces the actual field of flow outside of the slipstream with close approximation.
Date: September 1, 1934
Creator: Wieselsberger, C
Partner: UNT Libraries Government Documents Department

Contribution to the theory of tail-wheel shimmy

Description: A basic theoretical and experimental investigation is made of the shimmy behavior of a swiveling landing gear, the experimental tests being conducted with a small wheel mounted over a continuous belt. Effects of wheel loading, rolling velocity, rearward position of the wheel with respect to the swivel axis, tire elasticity, and torsional flexibility of the fuselage are investigated both experimentally and theoretically. A major theoretical conclusion is that the motion of a landing gear moving in a straight line without fuselage elasticity is stable for a sufficiently large rearward position of the wheel behind the swivel axis, and this conclusion is well verified quantitatively by the experimental data.
Date: December 1, 1954
Creator: Melzer, M
Partner: UNT Libraries Government Documents Department

The Effect of Inlet Pressure and Temperature on the Efficiency of a Single Stage Impulse Turbine Having an 11.0-Inch Pitch-Line Diameter Wheel

Description: Efficiency tests have been conducted on a single-stage impulse engine having an 11-inch pitch-line diameter wheel with inserted buckets and a fabricated nozzle diaphragm. The tests were made to determine the effect of inlet pressure, Inlet temperature, speed, and pressure ratio on the turbine efficiency. An analysis is presented that relates the effect of inlet pressure and temperature to the Reynolds number of the flow. The agreement between the analysis and the experimental data indicates that the changes in turbine efficiency with Inlet pressure and temperature may be principally a Reynolds number effect.
Date: June 1, 1945
Creator: Gabriel, David S.; Carmen, Robert L. & Trautwein, Elmer E
Partner: UNT Libraries Government Documents Department

Effect of intense sound waves on a stationary gas flame

Description: Intense sound waves with a resonant frequency of 5000 cycles per second were imposed on a stationary propane-air flame issuing from a nozzle. In addition to a slight increase of the flame velocity, a fundamental change both in the shape of the burning zone and in the flow pattern could be observed. An attempt is made to explain the origin of the variations in the flame configuration on the basis of transition at the nozzle from jet flow to potential flow.
Date: July 1, 1950
Creator: Hahnemann, H & Ehret, L
Partner: UNT Libraries Government Documents Department

Effect of initial mixture temperature on flame speed of methane-air, propane-air, and ethylene-air mixtures

Description: Flame speeds based on the outer edge of the shadow cast by the laminar Bunsen cone were determined as functions of composition for methane-air mixtures at initial mixture temperatures ranging from -132 degrees to 342 degrees c and for propane-air and ethylene-air mixtures at initial mixture temperatures ranging from -73 degrees to 344 degrees c. The data showed that maximum flame speed increased with temperature at an increasing rate. The percentage change in flame speed with change in initial temperature for the three fuels followed the decreasing order, methane, propane, and ethylene. Empirical equations were determined for maximum flame speed as a function of initial temperature over the temperature range covered for each fuel. The observed effect of temperature on flame speed for each of the fuels was reasonably well predicted by either the thermal theory as presented by Semenov or the square-root law of Tanford and Pease.
Date: January 1, 1952
Creator: Dugger, Gordon L
Partner: UNT Libraries Government Documents Department

The Effect of Inlet Temperature and Pressure on the Efficiency of Single-Stage Impulse Turbine Having a 13.2-Inch Pitch-Line Diameter Wheel

Description: From Summary: "Efficiency tests have been conducted on a single-stage impulse turbine having a 13.2-inch pitch-line diameter wheel and a cast nozzle diaphragm over a range of turbine speeds from 3000 to 17,000 rpm, pressure ratios from 1.5 to 5.0, inlet total temperatures from 1200 deg to 2000 deg R, and inlet total pressures from 18 to 59 inches of mercury absolute. The effect of inlet temperature and pressure on turbine efficiency for constant pressure ration and blade-to-jet speed ration is correlated against a factor derived from the equation for Reynolds number. The degree of correlation indicates that the change in turbine efficiency with inlet temperature and pressure for constant pressure ration and blade-to-jet speed ration is principally a Reynolds number effect."
Date: September 1945
Creator: Chanes, Ernest R. & Carman, L. Robert
Partner: UNT Libraries Government Documents Department

Effect of interaction on landing-gear behavior and dynamic loads in a flexible airplane structure

Description: The effects of interaction between a landing gear and a flexible airplane structure on the behavior of the landing gear and the loads in the structure have been studied by treating the equations of motion of the airplane and the landing gear as a coupled system. The landing gear is considered to have nonlinear characteristics typical of conventional gears, namely, velocity-squared damping, polytropic air-compression springing, and exponential tire force-deflection characteristics. For the case where only two modes of the structure are considered, an equivalent three-mass system is derived for representing the airplane and landing-gear combination, which may be used to simulate the effects of structural flexibility in jig drop tests of landing gears. As examples to illustrate the effects of interaction, numerical calculations, based on the structural properties of two large airplanes having considerably different mass and flexibility characteristics, are presented.
Date: January 1, 1956
Creator: Cook, Francis E & Milwitzky, Benjamin
Partner: UNT Libraries Government Documents Department

Effect of increasing the size of the valve-guide boss on the exhaust-valve temperature and the volumetric efficiency of an aircraft cylinder

Description: From Summary: "An exhaust-port design was developed that provides a heat-flow path of increased area from the valve stem to the outside surface of a Wright C9GC cylinder. The effects of the new port design on exhaust-valve temperature and volumetric efficiency were determined from single-cylinder engine tests. A reduction of 70 degrees Fahrenheit in the exhaust-valve temperature was obtained with no decrease in volumetric efficiency or power output."
Date: February 1945
Creator: Peters, Max D.
Partner: UNT Libraries Government Documents Department

The effect of increase in combustion-air inlet temperature from 80 to 130 F on the sea-level performance of a 22-inch-diameter pulse-jet engine

Description: Report discussing testing on 22 inch-diameter pulse-jet engines to determine the effect on performance of a change in combustion-air temperature from approximately 80 degrees to 130 degrees. The effects on jet thrust, combustion-air flow, and engine thrust are described.
Date: July 1946
Creator: Valerino, Michael F.; Essig, Robert H. & Hughes, Richard F.
Partner: UNT Libraries Government Documents Department

The effect of increased cooling surface on performance of aircraft-engine cylinders as shown by tests of the NACA cylinder

Description: 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.
Date: January 1, 1944
Creator: Schey, Oscar W.; Rollin, Verne G. & Ellerbrock, Herman H., Jr.
Partner: UNT Libraries Government Documents Department