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Computed Temperature Distribution and Cooling of Solid Gas-Turbine Blades

Description: "Computations were made to determine the temperature distribution and cooling of solid gas-turbine blades.A range of temperatures was used from 1500 degrees to 2500 degrees F, blade-root temperatures from 100 degrees to 1000 degrees F, blade thermal conductivity from 8 to 220 BTU/(hr)(sq ft)(degrees F/ft), and net gas to metal heat transfer coefficients from 75 to 250 BTU/(hr)(sq ft)(degrees F)" (p. 1).
Date: February 11, 1947
Creator: Reuter, J. George & Gazley, Carl, Jr.
Partner: UNT Libraries Government Documents Department

Wind-tunnel tests of several model tractor-propeller and pusher-propeller wing extension-shaft arrangements, special report

Description: From Summary: "Tests were made in the 20-foot propeller-research tunnel to investigate the possibility of obtaining increased net efficiencies of propeller-nacelle units by enclosing the engines in the wings and by using extension shafts. A wing of 5-foot chord was fitted with a propeller drive assembly providing for several axial locations of tractor propellers and pusher propellers. A three-blade 4-foot propeller and a three-blade 3 1/2-foot propeller of special design were tested in this wing with spinners and fairings ranging in diameter from 6 to 16 inches."
Date: June 1941
Creator: Harmon, Hubert N.
Partner: UNT Libraries Government Documents Department

Knock-Limited Performance of Triptane and 28-R Fuel Blends as Affected by Changes in Compression Ratio and in Engine Operating Variables

Description: From Summary: "A knock-limited performance investigation was conducted on blends of triptane and 28-P fuel with a 12-cylinder, V-type, liquid-cooled aircraft engine of 1710-cubic-inch displacement at three compression ratios: 6.65, 7.93, and 9.68. At each compression ratio, the effect of changes in temperature of the inlet air to the auxiliary-stage supercharger and in fuel-air ratio were investigated at engine speeds of 2280 and. 3000 rpm. The results show that knock-limited engine performance, as improved by the use of triptane, allowed operation at both take-off and cruising power at a compression ratio of 9.68."
Date: March 11, 1947
Creator: Brun, Rinaldo J.; Feder, Melvin S. & Fisher, William F.
Partner: UNT Libraries Government Documents Department

Effect of Various Blade Modifications on Performance of a 16-Stage High-Pressure-Ratio Axial-Flow Compressor 1 - Effect on Over-All Performance Characteristics of Decreasing Twelfth Through Fifteenth State Stator-Blade Angles 3 Degrees

Description: The stator-blade angles in the twelfth to fifteenth stages of a 16-stage high-pressure-ratio axial-flow compressor were decreased 3 deg The over-all performance of this compressor is compared with the performance of the same compressor with standard blade angles. The matching characteristics of the modified compressor and a two-stage turbine were also obtained and compared with those of the compressor with the original blade angles and the same turbine.
Date: January 22, 1952
Creator: Medeiros, Arthur A.; Hatch, James E. & Dugan, James F., Jr.
Partner: UNT Libraries Government Documents Department

Effect of Angle of Incidence of Second-Stage Vane Assembly on Third-Stage Compressor-Blade Vibration and Engine Performance

Description: "Strain-gages were used to measure blade vibrations causing failures in the third stage of a production 11-stage axial-flow compressor. After the serious third-stage vibration was detected, a series of investigations were conducted with second-stage vane assemblies of varying angles of incidence. Curves presented herein show the effect of varying the angle of incidence of second-stage vane assembly on third-stage rotor-blade vibration amplitude and engine performance" (p. 1).
Date: June 12, 1951
Creator: Meyer, André J., Jr. & Calvert, Howard F.
Partner: UNT Libraries Government Documents Department

The Effect of Clearance Distribution on the Performance of a Compression-Ignition Engine with a Precombustion Chamber

Description: "The clearance distribution in a precombustion chamber cylinder head was varied so that for a constant compression ratio of 13.5 the spherical auxiliary chambers contained 20, 35, 50, and 70 per cent of the total clearance volume. Each chamber was connected to the cylinder by a single circular passage, flared at both ends, and of a cross-sectional area proportional to the chamber volume, thereby giving the same calculated air-flow velocity through each passage. Results of engine-performance tests are presented with variations of power, fuel consumption, explosion pressure, rate of pressure rise, ignition lag, heat loss to the cooling water, and motoring characteristics" (p. 1).
Date: November 1932
Creator: Moore, C. S. & Collins, J. H., Jr.
Partner: UNT Libraries Government Documents Department

Comparison of High-Speed Operating Characteristics of Size 215 Cylindrical-Roller Bearings as Determined in Turbojet Engine and in Laboratory Test Rig

Description: "A comparison of the operating characteristics of 75-millimeter-bore (size 215) cylindrical-roller one-piece inner-race-riding cage-type bearings was made using a laboratory test rig and a turbojet engine. Cooling correlation parameters were determined by means of dimensional analysis, and the generalized results for both the inner- and outer-race bearing operating temperatures are compared for the laboratory test rig and the turbojet engine. Inner- and outer-race cooling-correlation curves were obtained for the turbojet-engine turbine-roller bearing with the same inner- and outer-race correlation parameters and exponents as those determined for the laboratory test-rig bearing" (p. 1).
Date: November 28, 1951
Creator: Macks, E. Fred & Nemeth, Zolton N.
Partner: UNT Libraries Government Documents Department

Component Performance Investigation of J71 Type II Turbines 3 - Overall Performance of J71 Type IIA Turbine

Description: "The over-all component performance characteristics of the J71 Type IIA three-stage turbine were experimentally determined over a range of speed and over-all turbine total-pressure ratio at inlet-air conditions af 35 inches of mercury absolute and 700 deg. R. The results are compared with those obtained for the J71 Type IIF turbine, which was previously investigated, the two turbines being designed for the same engine application. Geometrically the two turbines were much alike, having the same variation of annular flow area and the same number of blades for corresponding stator and rotor rows" (p. 1).
Date: January 20, 1955
Creator: Schum, Harold J.; Davison, Elmer H. & Petrash, Donald A.
Partner: UNT Libraries Government Documents Department

Design and Evaluation of a Turbojet Exhaust Simulator, Utilizing a Solid-Propellant Rocket Motor, for Use in Free-Flight Aerodynamic Research Models

Description: A method has been developed for modifying a rocket motor so that its exhaust characteristics simulate those of a turbojet engine. The analysis necessary to the design is presented along with tests from which the designs are evaluated. Simulation was found to be best if the exhaust characteristics to be duplicated were those of a turbojet engine at high altitudes and with the afterburner operative.
Date: December 17, 1954
Creator: de Moraes, Carlos A.; Hagginbothom, William K., Jr. & Falanga, Ralph A.
Partner: UNT Libraries Government Documents Department

Altitude-Test-Chamber Investigation of McDonnell Afterburner on J34 Engine

Description: "An altitude-test-chamber investigation was conducted to determine the operational and performance characteristics of a McDonnell afterburner with a fixed-area exhaust nozzle on a J34 engine. At rated engine speed, the altitude limit, as determined by combustion blow-out, occurred as a band of unstable operation of about 6000-foot altitude in width with minimum altitude limits from 31,000 feet at a simulated flight Mach number of 0.40 to about 45,500 feet at a simulated flight Mach number of 1.00. Considerable difficulty was experienced in attempting to establish or maintain balanced-cycle engine operation at altitudes above 36,000 feet" (p. 1).
Date: June 2, 1949
Creator: Reller, John O. & Dowman, Harry W.
Partner: UNT Libraries Government Documents Department

Investigation of High-Performance Fuels in Multicylinder and in Single-Cylinder Engines at High and Cruising Engine Speeds

Description: "An investigation was conducted to compare the knock-limited performance of a 20-percent triptane blend in 28-K fuel with that of 28-R and 33-R fuels at high engine speeds, cruising speeds, and two compression ratios in an K-1830-94 multicylinder engine. Data were obtained with the standard compression ratio of 6.7 and with a compression ratio of 3.0. The three fuels were investigated at engine speeds of 1800, 2250, 2600, and 2800 rpm at high and low blower ratios" (p. 1).
Date: February 21, 1947
Creator: Bell, Arthur H.; Nelson, R. Lee & Richard, Paul H.
Partner: UNT Libraries Government Documents Department

Investigation of Single Stage Axial Fans

Description: The following investigations are connected with experiments on fans carried out by the author in the Gouttingen Aerodynamic Laboratory within the framework of the preliminary experiments for the new Gouttingen wind-tunnel project. A fan rotor was developed which had very high efficiency at the design point corresponding to moderate pressure and which, in addition, could operate at a proportionally high pressure, rise. To establish the determining operating factors the author carried out extensive theoretical investigation in Hannover. In this it was necessary, to depart from the usual assumption of vanishing radial velocities. The calculations were substantially lightened by the introduction of diagrams. The, first part of the.report describes the theoretical investigations; the second, the experiments carried out at Gouttingen.
Date: April 1944
Creator: Ruden, P.
Partner: UNT Libraries Government Documents Department

Investigation of X24C-2 10-Stage Axial-Flow Compressor 3 - Surge Characteristics

Description: Compressor operation at low air flows for a given speed is limited by unstable flow conditions, commonly called surge. An investigation of surge in centrifugal compressors (reference 1) showed that the pulsation of pressures and velocities occurred when the slope of the compressor characteristic curve was positive and that the magnitude and frequency, as well as the incidence of surge, depended on the capacity and resistance of the total system. Although the theory presented in reference 1 is applicable to axial-floe compressors, little experimental information is available on the surge characteristics of the individual stages of axial-flow compressors, or on the variation of the surge characteristics with operating conditions.
Date: August 6, 1948
Creator: Buckner, Howard A., Jr. & Downing, Richard M.
Partner: UNT Libraries Government Documents Department

A Method for Estimating Heat Requirements for Ice Prevention Gas Heated Hollow Propeller Blades

Description: Report presenting a method for determining the temperature and flow of heated gas necessary for ice prevention of hollow propeller blades in flight and icing conditions. A variety of conditions are taken into consideration and suggested simplifications and short methods are provided in order to not overcomplicate the design modifications.
Date: December 1947
Creator: Gray, V. H. & Campbell, R. G.
Partner: UNT Libraries Government Documents Department

Investigation of 10-Stage Axial-Flow X24C-2 Compressor, 1, Performance at Inlet Pressure of 21 Inches Mercury Absolute and Inlet Temperature of 538 Degrees R

Description: The performance at inlet pressure of 21 inches mercury absolute and inlet temperature of 538 R for the 10-stage axial-flow X24C-2 compressor from the X24C-2 turbojet engine was investigated. the peak adiabatic temperature-rise efficiency for a given speed generally occurred at values of pressure coefficient fairly close to 0.35.For this compressor, the efficiency data at various speeds could be correlated on two converging curves by the use of a polytropic loss factor derived.
Date: July 15, 1947
Creator: Schum, Harold J. & Buckner, Howard A., Jr.
Partner: UNT Libraries Government Documents Department

Performance Charts for a Turbojet System

Description: "Convenient charts are presented for computing the thrust, fuel consumption, and other performance values of a turbojet system. These charts take into account the effects of ram pressure, compressor pressure ratio, ratio of combustion-chamber-outlet temperature to atmospheric temperature, compressor efficiency, turbine efficiency, combustion efficiency, discharge-nozzle coefficient, losses in total pressure in the inlet to the jet-propulsion unit and in the combustion chamber, and variation in specific heats with temperature. The principal performance charts show clearly the effects of the primary variables and correction charts provide the effects of the secondary variables" (p. 1).
Date: June 1947
Creator: Pinkel, Benjamin & Karp, Irving M.
Partner: UNT Libraries Government Documents Department

Performance of a Mixed-Flow Impeller in Combination with Semivaneless Diffuser

Description: The performance of a mixed-flow impeller in combination with a semivaneless diffuser were experimentally investigated. The diameter of the impeller was 11.0 inches and a maximum tip diameter of 14.74 inches. The semivaneless diffuser had an overall diameter of 28.00 inches. The performance properties of the mixed-flow impeller were also investigated with a 34.00 inch vane loss diffuser having a transition section of the same geometry as the semivaneless diffuser.
Date: April 4, 1947
Creator: Laskin, Eugene B. & Kofskey, Milton G.
Partner: UNT Libraries Government Documents Department

Recent Development of the Two-Stroke Engine 2 - Design Features

Description: "Completing the first paper dealing with charging methods and arrangements, the present paper discusses the design forms of two-stroke engines. Features which largely influence piston running are: (a) The shape and surface condition of the sliding parts. (b) The cylinder and piston materials. (c) Heat conditions in the piston, and lubrication. There is little essential difference between four-stroke and two-stroke engines with ordinary pistons" (p. 1).
Date: May 1945
Creator: Zeman, J.
Partner: UNT Libraries Government Documents Department

Simulated Altitude Performance of Combustors for the 24C Jet Engine: 2: 24C-4 Combustor

Description: "The performance of a 24C-4 combustor was investigated with three different combustor baskets and five modifications of these baskets at conditions simulating static (zero-ram) operation of the 24C jet engine over ranges of altitude and engine speed to determine and improve the altitude operational limits of the 24C combustor. Information was also obtained regarding combustion characteristics, the fuel-flow characteristics of the fuel manifolds, and the combustor total-pressure drop. NACA modifications, which consisted of blocking rows of holes on the baskets, increased the minimum point on the altitude-operational-limit curve, which occurs at low engine speeds, for a narrow-upstream-end basket by 8000 feet (from 23, 000 to 31,000 ft) and for a wide-upstream-end basket by 21,000 feet (from 12, 000 to 34,000 ft)" (p. 1).
Date: November 12, 1947
Creator: Bernardo, Everett; Schroeter, Thomas T. & Miller, Robert C.
Partner: UNT Libraries Government Documents Department

Gas-Dynamic Investigations of the Pulse-Jet Tube, Parts 1 and 2

Description: Based upon a simplified representation of the mode of operation of the pulse-jet tube, the effect of the influences mentioned in the title were investigated and it will be shown that, for a jet tube with a form designed to be aerodynamically favorable, the ability to operate is at least questionable. This investigation will account for the important practical observation made by Paul Schmidt that the ratio of the effective valve cross-sectional area to the tube cross section may not be of any random magnitude and will explain why at too great flight speeds the jet tube ceases to operate. Chemical an thermodynamic processes (for example, constituents or mode of fuel-air-mixture formation or heat losses) are unimportant in this regard.
Date: February 1947
Creator: Schultz-Grunow, F.
Partner: UNT Libraries Government Documents Department

Performance of Single-Stage Turbine of Mark 25 Torpedo Power Plant with Two Special Nozzles 2 - Efficiency with 20 Degrees-Inlet-Angle Rotor Blades

Description: "A single-stage modification of the turbine from a Mark 25 torpedo power plant was investigated to determine the performance with two nozzle designs in combination with special rotor blades having a 20 inlet angle. The performance is presented in terms of blade, rotor, and brake efficiency as a function of blade-jet speed ratio for pressure ratios of 8, 15 (design), and 20. The blade efficiency with the nozzle having circular pas- sages (K) was equal to or higher than that with the nozzle having rectangular passages (J) for all pressure ratios and speeds investigated" (p. 1).
Date: August 25, 1949
Creator: Schum, Harold J. & Whitney, Warren J.
Partner: UNT Libraries Government Documents Department

Tandem Air Propellers

Description: Report discussing tests of 2-blade, adjustable-pitch, counterrotating tandem model propellers, adjusted to absorb equal power at maximum efficiency. The characteristics at several pitch settings and diameter spacings were compared with 2-blade and 4-blade propellers. Tandem propellers were found to have an advantage over single propellers at higher pitch settings.
Date: August 1937
Creator: Lesley, E. P.
Partner: UNT Libraries Government Documents Department

Altitude Performance of J35-A-17 Turbojet Engine in an Altitude Chamber

Description: "An investigation of the altitude performance characteristics of an Allison J35-A-17 turbojet engines have been conducted in an altitude chamber at the NACA Lewis laboratory. Engine performance was obtained over a range of altitudes from 20,000 to 60,000 feet at a flight Mach number of 0.62 and a range of flight Mach numbers from 0.42 to 1.22 at an altitude of 30,000 feet. The performance of the engine over the range investigated could be generalized up to an altitude of 30,000 feet" (p. 1).
Date: January 3, 1951
Creator: Vincent, K. R. & Gale, B. M.
Partner: UNT Libraries Government Documents Department

Practical Possibilities of High-Altitude Flight with Exhaust-Gas Turbines in Connection with Spark Ignition Engines Comparative Thermodynamic and Flight Mechanical Investigations

Description: As a means of preparing for high-altitude flight with spark-ignition engines in conjunction with exhaust-gas turbosuperchargers, various methods of modifying the exhaust-gas temperatures, which are initially higher than a turbine can withstand are mathematically compared. The thermodynamic results first obtained are then examined with respect to the effect on flight speed, climbing speed, ceiling, economy, and cruising range. The results are so presented in a generalized form that they may be applied to every appropriate type of aircraft design and a comparison with the supercharged engine without exhaust-gas turbine can be made.
Date: April 1947
Creator: Weise, A.
Partner: UNT Libraries Government Documents Department