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Investigation of frequency-response characteristics of engine speed for a typical turbine-propeller engine

Description: Experimental frequency-response characteristics of engine speed for a typical turbine-propeller engine are presented. These data were obtained by subjecting the engine to sinusoidal variations of fuel flow and propeller-blade-angle inputs. Correlation is made between these experimental data and analytical frequency-response characteristics obtained from a linear differential equation derived from steady-state torque-speed relations.
Date: March 24, 1950
Creator: Taylor, Burt L., III & Oppenheimer, Frank L.
Partner: UNT Libraries Government Documents Department

The flexible mounting of an airplane engine

Description: Discussed here is the suggested installation of the 'unbalanced' 8-cylinder VE-engine. The suggestion was that a flexible mounting be used instead of bolting the engine rigidly to the airplane structure. It was concluded that a flexible connection between the engine and the airplane is probably possible. A flexible connection primarily diminishes the vibrations due to inertia and, to a lesser degree, those due to torque variation. However, engines vibrate more when freely suspended than when rigidly mounted, and this vibration has a detrimental effect on all connections between the engine and the airplane. Therefore, in view of the relatively insignificant advantages which may be derived from the elastic suspension of the engine, the present rigid mounting is to be preferred. Vibration reduction can be achieved by incorporating in the fuselage as many of the rigid airplane parts as possible.
Date: July 1923
Creator: Kutzbach, K.
Partner: UNT Libraries Government Documents Department

Preliminary evaluation of the performance of a uniflow two-stroke-cycle spark-ignition engine combined with a blowdown turbine and a steady-flow turbine

Description: Report presenting calculations based on a theoretical analysis for a composite engine consisting of a uniflow two-stroke-cycle spark-ignition engine, a compressor, a blowdown turbine, and a steady-flow turbine. Operation of the engine is considered for four cases of gas mixtures and steady-flow turbine temperatures.
Date: November 25, 1947
Creator: Sather, Bernard I. & Foster, Hampton H.
Partner: UNT Libraries Government Documents Department

Altitude Starting Tests of a 1000-Pound-Thrust Solid-Propellant Rocket

Description: Four solid-propellant rocket engines of nominal 1000-pound-thrust were tested for starting characteristics at pressure altitudes ranging from 112,500 to 123,000 feet and at a temperature of -75 F. All engines ignited and operated successfully. Average chamber pressures ranged from 1060 to ll90 pounds per square inch absolute with action times from 1.51 to 1.64 seconds and ignition delays from 0.070 t o approximately 0.088 second. The chamber pressures and action times were near the specifications, but the ignition delay was almost twice the specified value of 0.040 second.
Date: August 27, 1952
Creator: Sloop, John L.; Rollbuhler, R. James & Krawczonek, Eugene M.
Partner: UNT Libraries Government Documents Department

Investigation of a high-temperature single-stage turbine suitable for air cooling and turbine stator adjustment 2: performance of vortex turbine at various stator settings

Description: Report presenting a consideration of a mode of engine operation that requires operational flexibility of the turbine, which requires that the turbine stator and exhaust nozzle area are adjusted to maintain a fixed compressor operating point. Results regarding turbine performance and comparison of predicted and experimental turbine performance are provided.
Date: August 3, 1954
Creator: Heaton, Thomas R.; Holeski, Donald E. & Forrette, Robert E.
Partner: UNT Libraries Government Documents Department

Cooling Characteristics of the V-1650-7 Engine, 1, Coolant-Flow Distribution, Cylinder Temperatures, and Heat Rejections at Typical Operating Conditions

Description: From Summary: "An investigation was conducted to determine the coolant-flow distribution, the cylinder temperatures, and the heat rejections of the V-1650-7 engine . The tests were run a t several power levels varying from minimum fuel consumption to war emergency power and at each power level the coolant flows corresponded to the extremes of those likely to be encountered in typical airplane installations, A mixture of 30-percent ethylene glycol and 70-percent water was used as the coolant. The temperature of each cylinder was measured between the exhaust valves, between the intake valves, in the center of the head, on the exhaust-valve guide, at the top of the barrel on the exhaust side, and on each exhaust spark-plug gasket."
Date: May 23, 1947
Creator: Povolny, John H. & Bogdan, Louis J.
Partner: UNT Libraries Government Documents Department

Regenerative-cooling studies in a 5000-pound-thrust liquid-oxygen - JP-4 rocket engine operated at 6000-pounds-per-square-inch combustion-chamber pressure

Description: A study attempting to demonstrate the feasibility of fuel cooling a liquid-oxygen-JP-4 rocket engine operating at a chamber pressure of 600 pounds per square inch and to obtain data for the heat-transfer rates at this chamber pressure. No difficulties were experienced when cooling the engine. Results regarding heat transfer and performance are provided.
Date: April 17, 1956
Creator: Tischler, Adelbert O. & Humphrey, Jack C.
Partner: UNT Libraries Government Documents Department

Altitude-Wind-Tunnel Investigation of a 3000-Pound-Thrust Axial-Flow Turbojet Engine, 7, Pressure and Temperature Distributions

Description: Temperature and pressure distributions for an original and modified 3000 pound thrust axial flow turbojet engine were investigated. Data are included for a range of simulated altitudes from 5000 to 45000 feet, Mach numbers from 0.24 to 1.08, and corrected engine speeds from 10,550 to 13,359 rpm.
Date: December 10, 1948
Creator: Saari, Martin J. & Prince, William R.
Partner: UNT Libraries Government Documents Department

Investigation of altitude performance of AN-F-58 fuels in annular combustor of J34-WE-22 engine

Description: From Summary: "An investigation was conducted in the combustor of a 3000-pound-thrust turbojet engine to determine the altitude performance characteristics of AN-F-58 fuels. Three fuels conforming to AN-F-58 specification were prepared in order to determine the influence of boiling-temperature range and aromatic content on altitude performance. The performance of the three AN-F-58 fuels was compared with the performance of AN-F-48 (grade 100/130) fuel in the range of simulated altitudes from 20,000 to 55,000 feet, corrected engine speeds from 6000 to 12,500 rpm, and flight Mach numbers of 0.2 and 0.6."
Date: December 5, 1949
Creator: Tischler, Adelbert O. & Scull, Wilfred E.
Partner: UNT Libraries Government Documents Department

Effect of uneven air-flow distribution to the twin inlets of an axial-flow turbojet engine

Description: Report presenting a brief investigation conducted to determine the effects of a 60-40 air flow distribution to the twin inlet ducts of an axial-flow turbojet engine. Data were obtained over a range of exhaust gas temperatures at several altitudes at Mach number 0.64. Results regarding the effect on pressure and temperature patterns, compressor performance, effect on combustor and turbine performance, engine pumping characteristics, and operational characteristics are provided.
Date: January 26, 1953
Creator: Wallner, Lewis E.; Conrad, E. William & Prince, William R.
Partner: UNT Libraries Government Documents Department

Performance of multiple jet-exit installations

Description: Report presenting an investigation of the performance of clustered jet-exit installations at Mach numbers from 0.60 to 3.05. The data were obtained with tunnel-wall-mounted models with cold-air-jet exhaust. Results indicated that large base-pressure drag coefficients may be encountered in the transonic and low supersonic speed range and that the best configuration in the test was boattailed between the nacelles, had a cylindrical nacelle afterbody, and a divergent nozzle with a design pressure ratio of 15.
Date: July 7, 1958
Creator: Swihart, John M. & Nelson, William J.
Partner: UNT Libraries Government Documents Department

Preliminary comparison of 17- and 75-millimeter-bore cageless cylindrical roller bearings with conventional cylindrical roller bearings at high speeds

Description: Preliminary results at high speeds indicate lower bearing temperatures, less internal bearing wear, and greater reliability of the conventional, cage-type cylindrical roller bearings than of either full-complement or special cageless roller bearings of the types investigated, although the latter bearing types have been operated successfully to DN values of 1.0 X 10 superscript 6.
Date: March 5, 1953
Creator: Macks, E. Fred; Anderson, W. J. & Nemeth, Zolton N.
Partner: UNT Libraries Government Documents Department

Identification of knock in NACA high-speed photographs of combustion in a spark-ignition engine

Description: Report presents the results of a study of combustion in a spark-ignition engine given in NACA Technical Reports 704 and 727. The present investigation was made with the NACA high-speed motion-picture camera, operating at 40,000 photographs a second, and with a cathode-ray oscillograph operating on a piezoelectric pick-up in the combustion chamber. Photographs are presented showing that the origin of knock is not necessarily in the end gas. The data obtained indicates that knock takes place only in a part of the cylinder charge which has been previously ignited either by autoignition or by the passage of the flame fronts but which has not burned to completion. Mottled regions in the high-speed Schlieren photographs are demonstrated to represent combustion regions.
Date: November 14, 1942
Creator: Miller, Cearcy D. & Olsen, H. Lowell
Partner: UNT Libraries Government Documents Department

Heat transfer in geometrically similar cylinders

Description: The power and heat-stress conditions of geometrically similar engines are discussed. The advantages accruing from smaller cylinder dimensions are higher specific horsepower, lower weight per horsepower, lower piston temperature, and less frontal area, with reduced detonation tendency.
Date: May 1941
Creator: Riekert, P. & Held, A.
Partner: UNT Libraries Government Documents Department

Acceleration Characteristics of R-3350 Engine Equipped with NACA Injection Impeller

Description: From Summary: "Qualitative investigations have shown that use of the NACA injection impeller with the R-3350 engine increases the inertia of the fuel-injection system and, when the standard fuel-metering system is used, this increase in inertia results in poor engine acceleration characteristics. This investigation was therefore undertaken to determine whether satisfactory acceleration characteristics of the engine equipped with the injection impeller could be obtained by simple modifications to the fuel-monitoring system. The engine was operated with two types of carburetor; namely, a hydraulic-metering carburetor incorporating a vacuum-operated accelerating pump and a direct-metering carburetor having a throttle-actuated accelerating pump."
Date: January 8, 1947
Creator: Hickel, Robert O. & Snider, William E.
Partner: UNT Libraries Government Documents Department

The effect of changing the ratio of exhaust-valve flow capacity to inlet-valve flow capacity on volumetric efficiency and output of a single-cylinder engine

Description: Report presenting a series of tests with a single-cylinder engine in order to determine the effect on volumetric efficiency and on engine performance of changing the ratio of exhaust-valve flow capacity to inlet-valve flow capacity when operating with exhaust pressure equal to inlet pressure.
Date: October 1947
Creator: Eppes, James V. D.; Livengood, James C. & Taylor, C. Fayette
Partner: UNT Libraries Government Documents Department

Effect of combustion-chamber shape on the performance of a prechamber compression-ignition engine

Description: The effect on engine performance of variations in the shape of the prechamber, the shape and direction of the connecting passage, the chamber volume using a tangential passage, the injection system, and the direction od the fuel spray in the chamber was investigated using a 5 by 7 inch single-cylinder compression-ignition engine. The results show that the performance of this engine can be considerably improved by selecting the best combination of variables and incorporating them in a single design. The best combination as determined from these tests consisted of a disk-shaped chamber connected to the cylinder by means of a flared tangential passage. The fuel was injected through a single-orifice nozzle directed normal to the air swirl and in the same plane. At an engine speed of 1,500 r.p.m. and with the theoretical fuel quantity for no excess air, the engine developed a brake mean effective pressure of 115 pounds per square inch with a fuel consumption of 0.49 pound per brake horsepower-hour and an explosion pressure of 820 pounds per square inch. A brake mean effective pressure of 100 pounds per square inch with a brake-fuel consumption of 0.44 pound per horsepower-hour at 1,500 r.p.m. was obtained.
Date: December 1934
Creator: Moore, C. S. & Collins, J. H., Jr.
Partner: UNT Libraries Government Documents Department

Preignition-limited performance of several fuels

Description: 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.
Partner: UNT Libraries Government Documents Department

The charging process in a high-speed, single-cylinder, four-stroke engine

Description: From Summary: "Experimental measurements and theoretical calculations were made on an aircraft-type, single cylinder engine, in order to determine the physical nature of the inlet process, especially at high piston speeds. The engine was run at speeds from 1,500 to 2,600 r.p.m. (mean piston speeds of 1,370 to 2,380 feet per minute). Measurements were made of the cylinder pressure during the inlet stroke and of the power output and volumetric efficiency. Measurements were also made, with the engine not running, to determine the resistance and mass of air in the inlet valve port at various crank angles. Results of analysis indicate that mass has an appreciable effect, but friction plays the major part in restricting flow. The observed fact that the volumetric efficiency is considerably less than 100 percent is attributed to thermal effects. An estimate was made of the magnitude of these effects in the present case, and their general nature is discussed."
Date: February 1939
Creator: Reynolds, Blake; Schecter, Harry & Taylor, E. S.
Partner: UNT Libraries Government Documents Department

Effect of preignition on cylinder temperatures, pressures, power output, and piston failures

Description: Report presenting an investigation using a cylinder of a V-type liquid-cooled engine to observe the behavior of the cylinder when operated under preignition conditions. The effects of fuel-air ratio, power output, aromatic content of fuel, engine speed, mixture temperature, and preignition source are provided.
Date: June 1948
Creator: Corrington, Lester C. & Fisher, William F.
Partner: UNT Libraries Government Documents Department

The calculated performance of airplanes equipped with supercharging engines

Description: In part one of this report are presented the theoretical performance curves of an airplane engine equipped with a supercharging compressor. In predicting the gross power of a supercharging engine, the writer uses temperature and pressure correction factors based on experiments made at the Bureau of Standards (NACA report nos. 45 and 46). Means for estimating the temperature rise in the compressor are outlined. Part two of this report presents an estimation of the performance curves of an airplane fitted with a supercharging engine. A supercharging installation suitable for commercial use is described, and it is shown that with the use of the compressor a great saving in fuel and a considerable increase in carrying capacity can be effected simultaneously. In an appendix the writer derives a theoretical formula for the correction of the thrust coefficient of an airscrew to offset the added resistance of the airplane due to the slip-stream effect.
Date: 1921
Creator: Kemble, E. C.
Partner: UNT Libraries Government Documents Department

Comparative study of turbofan and turbojet engines

Description: Report presents a comparison of turbofan and turbojet engines for Mach numbers of up to 3.0 and conventional hydrocarbon fuels. There are four parts of the report: a cycle analysis of turbofan engines and information about their designs, a comparison of several commercial engines proposed for the Air Force, component performance and development problems for turbofan and turbojet engines, and a summary and conclusions based on mission studies.
Date: July 19, 1957
Creator: Kaufman, Harold R.; Benser, William A. & Gabriel, David S.
Partner: UNT Libraries Government Documents Department