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  • AIRCRAFT PROPULSION AND POWER  (270)
  • 1975-1979  (270)
  • 1977  (270)
  • 101
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    Summary of forward velocity effects on fan noise (1977)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Available experimental data comparing the in-flight and static behavior of fan noise are reviewed. These results are then compared with recent data obtained for a fan stage tested with forward velocity in a low speed wind tunnel. Tentative conclusions are presented about the significance and nature of the changes in noise observed when a forward velocity is imposed. Finally, the implications of the emerging picture of in-flight fan source noise for suppressor design are discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-73722 , E-9209 , Aeroacoustics Conf.; Oct 03, 1977 - Oct 05, 1977; Atlanta
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    NASA TECHNICAL REPORTS
  • 102
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    Effects of Simulated Flight on Fan Noise Suppression (1977)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Attenuation properties of three treated fan inlets were evaluated. Tunnel flow simulated the inflow clean-up effect on source noise observed in flight and allowed observation of the blade passage frequency tone cut-off phenomenon. Acoustic data consisted of isolated inlet noise measured in the far field at two fixed positions and with traverses at four frequencies. Attenuation and source noise properties with and without flight simulation are compared and discussed. Averaged attenuation properties showed relative agreement of the inlets with their design intent, however, tunnel flow significantly affected the attenuation spectra.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-73708 , E-9247 , Aeroacoustics Conf.; Oct 03, 1977 - Oct 05, 1977; Atlanta
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    NASA TECHNICAL REPORTS
  • 103
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    Aero-acoustic performance comparison of core engine noise suppressors on NASA quiet engine C (1977)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The relative aero-acoustic effectiveness of two core engine suppressors, a contractor-designed suppressor delivered with the Quiet Engine, and a NASA-designed suppressor was evaluated. The NASA suppressor was tested with and without a splitter making a total of three configurations being reported in addition to the baseline hardwall case. The aerodynamic results are presented in terms of tailpipe pressure loss, corrected net thrust, and corrected specific fuel consumption as functions of engine power setting. The acoustic results are divided into duct and far-field acoustic data. The NASA-designed core suppressor did the better job of suppressing aft end noise, but the splitter associated with it caused a significant engine performance penality. The NASA core suppressor without the spltter suppressed most of the core noise without any engine performance penalty.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-73662 , E-9182 , Propulsion Conf.; Jul 11, 1977 - Jul 13, 1977; Orlando, FL; United States
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    NASA TECHNICAL REPORTS
  • 104
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    The effect of ambient temperature and humidity on the carbon monoxide emissions of an idling gas turbine (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Changes in ambient temperature and humidity affect the exhaust emissions of a gas turbine engine. The results of a test program employing a JT8D combustor are presented which quantize the effect of these changes on carbon monoxide emissions at simulated idle operating conditions. Analytical results generated by a kinetic model of the combustion process and reflecting changing ambient conditions are given. It is shown that for a complete range of possible ambient variations, significant changes do occur in the amount of carbon monoxide emitted by a gas turbine engine.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Spring Technical Meeting; Mar 28, 1977 - Mar 30, 1977; Cleveland, OH
    Format: text
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    NASA TECHNICAL REPORTS
  • 105
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    Rotor burst protection program: Statistics on aircraft gas turbine engine rotor failures that occurred in US commercial aviation during 1975 (1977)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Statistics on gas turbine rotor failures that have occurred in U.S. commercial aviation during 1975 are presented. The compiled data were analyzed to establish: (1) The incidence of rotor failures and the number of contained and uncontained rotor bursts; (2) The distribution of rotor bursts with respect to engine rotor component; i.e., fan, compressor or turbine; (3) The type of rotor fragment (disk, rim or blade) typically generated at burst; (4) The cause of failure; (5) The type of engines involved; and (6) The flight condition at the time of failure.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135304 , NAPTC-PE-106
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  • 106
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    Effects of simulated flight on fan noise suppression (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Attenuation properties of three treated fan inlets were evaluated in the NASA-Lewis Anechoic Wind Tunnel using a subsonic tip speed, 50.8 cm-diameter fan. Tunnel flow simulated the inflow clean-up effect on source noise observed in flight and allowed observation of the blade passage frequency tone cut-off phenomenon. Acoustic data consisted of isolated inlet noise measured in the far field at two positions and with traverses at four frequencies. Averaged attenuation properties showed relative agreement of the inlets with their design intent; however, tunnel flow significantly affected the attenuation spectra. With no tunnel flow the strong blade passage tone was more highly attenuated than the adjacent broadband noise. With tunnel flow, when cut-off was observed, the attenuation at the tone frequency was comparable to that for broadband noise. Tunnel flow increased by several dB the maximum attenuation occurring at midfrequencies of the attenuation spectra. The combined effect of tunnel flow on attenuation and source noise resulted in suppressed fan noise levels throughout the spectra. Tunnel flow caused some substantial directivity variations that are interpreted as acoustic mode changes, with tunnel flow generally reducing the proportion of modes near cut-off.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 77-1334 , Aeroacoustics Conference; Oct 03, 1977 - Oct 05, 1977; Atlanta, GA
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  • 107
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    Effects of forward motion on jet and core noise (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: A study was conducted to investigate the effects of forward motion on both jet and core noise. Measured low-frequency noise from static-engine and from flyover tests with a DC-9-30 powered by JT8D-109 turbofan engines and with a DC-10-40 powered by JT9D-59A turbofan engines was separated into jet- and core noise components. Comparisons of the static and the corresponding in-flight jet- and core-noise components are presented. The results indicate that for the DC-9 airplane at low power settings, where core noise is predominant, the effect of convective amplification on core-noise levels is responsible for the higher in-flight low-frequency noise levels in the inlet quadrant. Similarly, it was found that for the DC-10 airplane with engines mounted under the wings and flaps and flap deflection greater than 30 degrees, the contribution from jet-flap-interaction noise is as much as 5 dB in the inlet quadrant and is responsible for higher in-flight low-frequency noise levels during approach conditions. Those results indicate that to properly investigate flight effects, it is important to consider the noise contributions from other low-frequency sources, such as the core and the jet-flap interaction.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 77-1330 , DOUGLAS-6616 , Aeroacoustics Conference; Oct 03, 1977 - Oct 05, 1977; Atlanta, GA
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  • 108
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    Measurement of far field combustion noise from a turbofan engine using coherence functions (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Coherence measurements between fluctuating pressure in the combustor of a YF-102 turbofan engine and far-field acoustic pressure were made. The results indicated that a coherent relationship between the combustor pressure and far-field existed only at frequencies below 250 Hz, with the peak occurring near 125 Hz. The coherence functions and the far-field spectra were used to compute the combustor-associated far-field noise in terms of spectra, directivity, and acoustic power, over a range of engine operating conditions. The acoustic results so measured were compared with results obtained by conventional methods, as well as with various semiempirical predictions schemes. Examination of the directivity patterns indicated a peak in the combustion noise near 120 deg (relative to the inlet axis).
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 77-1277 , Aeroacoustics Conference; Oct 03, 1977 - Oct 05, 1977; Atlanta, GA
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  • 109
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    Experimental and analytical separation of hydrodynamic, entropy and combustion noise in a gas turbine combustor (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: This paper deals with noise sources which are central to the problem of core engine noise in turbopropulsion systems. The sources dealt with are entropy noise and direct combustion noise, as well as a non-propagating psuedosound which is hydrodynamic noise. It is shown analytically and experimentally that a transition can occur from a combustion noise dominant situation to an entropy noise dominant case if the contraction of a terminating nozzle to the combustor is high enough. In the combustor tested, entropy noise is the dominant source for propagational noise if the combustor is choked at the exit. Analysis techniques include spectral, cross spectral, cross correlation, and ordinary and partial coherence analysis. Measurements include exterior and interior fluctuating and mean pressures and temperatures.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 77-1275 , Aeroacoustics Conference; Oct 03, 1977 - Oct 05, 1977; Atlanta, GA
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    NASA TECHNICAL REPORTS
  • 110
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    Theoretical jet exhaust noise model for the duct burning turbofan (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: A model was developed to predict the acoustic power spectrum for a Duct Burning Turbofan (DBTF) whose cycle results in a high velocity, high temperature fan stream and a lower velocity, lower temperature primary stream. Model tests have demonstrated that a DBTF may produce substantially less noise than a conventional turbojet with the same thrust and weight flow. Predictions from the model agreed well with measured data from the model tests. The characteristics of the DBTF acoustic power spectrum were shown to be related to the rapid mixing of the fan and primary streams. The effects of fan to primary velocity ratio, temperature ratio, area ratio, and the effect of nozzle geometry on DBTF jet noise were determined.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 77-1264 , Aeroacoustics Conference; Oct 03, 1977 - Oct 05, 1977; Atlanta, GA
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  • 111
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    Quiet, Clean, Short-Haul Experimental Engines /QCSEE/ - A technology development program (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: NASA's QCSEE Program (Quiet, Clean, Short-Haul Experimental Engine) performed by the General Electric Company covers a wide range of advanced propulsion technology features applicable to future subsonic engine concepts. These technology features are combined into two engine and nacelle configurations for demonstration of program goals. This paper presents descriptions of two engine/nacelle configurations and shows the flow of technology developed in component programs into the configurations. The under-the-wing (UTW) configuration, featuring major innovative and advanced components, such as a large variable pitch fan and a composite material integrated engine and nacelle structure, has been tested at General Electric's Peebles, Ohio test facility. The key characteristics of the engine as observed from the initial test series are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: ASME PAPER 77-GT-109 , Gas Turbine Conference and Products Show; Mar 27, 1977 - Mar 31, 1977; Philadelphia, PA
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    NASA TECHNICAL REPORTS
  • 112
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    NASA Quiet, Clean General Aviation Turbofan /QCGAT/ program status (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Emissions pollution studies, noise studies, and engine performance studies and their place in QCGAT developmental program status are reported. The Lycoming TFE 731 turbofan engine, the GE T700-GE-700 high bypass ratio turbofan, and the AVCO-Lycoming LTS 101 turboshaft engine are prominent candidates in the tests for urban quiet turbofan service. Two phases in the program are characterized. Engine quieting, polluting emissions abatement, and fuel economies are particularly important for the anticipated rise in number of jet propulsion craft using smaller airports adjacent to communities accustomed to low noise/pollution backgrounds.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: ASME PAPER 77-GT-77 , Gas Turbine Conference and Products Show; Mar 27, 1977 - Mar 31, 1977; Philadelphia, PA
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  • 113
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    Containment of composite fan blades (1977)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The development of containment concepts for use with large composite fan blades, taking into account the frangible nature of composite blades is considered. Aspects of the development program include; (1) an analysis to predict the interaction between a failed fan blade and the blade containment structure; (2) scaling factors to allow impact testing using subscale containment rings and simulated blades; (3) the design and fabrication of containment systems for further evaluation in a rotating rig test facility; (4) evaluate the test data against the analytically predicted results; and (5) determine overall systems weights and design characteristics of a composite fan stage installation and compare to the requirements of an equivalent titanium fan blade system. Progress in the blade impact penetration tests and the design and fabrication of blade containment systems is reported.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-158168 , QPR-4 , R77AEG450
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    NASA TECHNICAL REPORTS
  • 114
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    Quiet Clean Short-haul Experimental Engine (QCSEE) under-the-wing engine composite fan blade design report (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A total of 38 quiet clean short haul experimental engine under the wing composite fan blades were manufactured for various component tests, process and tooling, checkout, and use in the QCSEE UTW engine. The component tests included frequency characterization, strain distribution, bench fatigue, platform static load, whirligig high cycle fatigue, whirligig low cycle fatigue, whirligig strain distribution, and whirligig over-speed. All tests were successfully completed. All blades planned for use in the engine were subjected to and passed a whirligig proof spin test.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135046 , R77AEG177
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  • 115
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    Quiet Clean Short-haul Experimental Engine (QCSEE) main reduction gears detailed design report (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Lightweight turbine engines with geared slower speed fans are considered. The design of two similar but different gear ratio, minimum weight, epicyclic star configuration main reduction gears for the under the wing (UTW) and over the wing (OTW) engines is discussed. The UTW engine reduction gear has a ratio of 2.465:1 and a 100% power design rating of 9885 kW (13,256 hp) at 3143 rpm fan speed. The OTW engine reduction gear has a ratio of 2.062:1 and a 100% power design rating of 12813 kW (17183 hp) at 3861 rpm fan speed. Details of configuration, stresses, deflections, and lubrication are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134872 , CW-WR-77-024
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    NASA TECHNICAL REPORTS
  • 116
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    Quiet Clean Short-haul Experimental Engine (QCSEE) main reduction gears test program (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Sets of under the wing (UTW) engine reduction gears and sets of over the wing (OTW) engine reduction gears were fabricated for rig testing and subsequent installation in engines. The UTW engine reduction gears which have a ratio of 2.465:1 and a design rating of 9712 kW at 3157 rpm fan speed were operated at up to 105% speed at 60% torque and 100% speed at 125% torque. The OTW engine reduction gears which have a ratio of 2.062:1 and a design rating of 12,615 kW at 3861 rpm fan speed were operated at up to 95% speed at 50% torque and 80% speed at 109% torque. Satisfactory operation was demonstrated at powers up to 12,172 kW, mechanical efficiency up to 99.1% UTW, and a maximum gear pitch line velocity of 112 m/s (22,300 fpm) with a corresponding star gear spherical roller bearing DN of 850,00 OTW. Oil and star gear bearing temperatures, oil churning, heat rejection, and vibratory characteristics were acceptable for engine installation.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134669 , CW-WR-77-008
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    NASA TECHNICAL REPORTS
  • 117
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    Acoustic analysis of aft noise reduction techniques measured on a subsonic tip speed 50.8 cm (twenty inch) diameter fan (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Sound data which were obtained during tests of a 50.8 cm diameter, subsonic tip speed, low pressure ratio fan were analyzed. The test matrix was divided into two major investigations: (1) source noise reduction techniques; and (2) aft duct noise reduction with acoustic treatment. Source noise reduction techniques were investigated which include minimizing second harmonic noise by varying vane/blade ratio, variation in spacing, and lowering the Mach number through the vane row to lower fan broadband noise. Treatment in the aft duct which includes flow noise effects, faceplate porosity, rotor OGV treatment, slant cell treatment, and splitter simulation with variable depth on the outer wall and constant thickness treatment on the inner wall was investigated. Variable boundary conditions such as variation in treatment panel thickness and orientation, and mixed porosity combined with variable thickness were examined. Significant results are reported.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134891 , R75AEG368
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  • 118
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    Quiet Clean Short-haul Experimental Engine (QCSEE) Over The Wing (OTW) design report (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The design, fabrication, and testing of two experimental high bypass geared turbofan engines and propulsion systems for short haul passenger aircraft are described. The propulsion technology required for future externally blown flap aircraft with engines located both under the wing and over the wing is demonstrated. Composite structures and digital engine controls are among the topics included.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134848 , R75AEG443
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  • 119
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    Quiet Clean Short-haul Experimental Engine (QCSEE): The aerodynamic and mechanical design of the QCSEE under-the-wing fan (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The design, fabrication, and testing of two experimental high bypass geared turbofan engines and propulsion systems for short haul passenger aircraft are described. The aerodynamic and mechanical design of a variable pitch 1.34 pressure ratio fan for the under the wing (UTW) engine are included. The UTW fan was designed to permit rotation of the 18 composite fan blades into the reverse thrust mode of operation through both flat pitch and stall pitch directions.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135009 , R75AEG484
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  • 120
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    Quiet Clean Short-haul Experimental Engine (QCSEE) Under-The-Wing (UTW) composite nacelle subsystem test report (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The element and subcomponent testing conducted to verify the under the wing composite nacelle design is reported. This composite nacelle consists of an inlet, outer cowl doors, inner cowl doors, and a variable fan nozzle. The element tests provided the mechanical properties used in the nacelle design. The subcomponent tests verified that the critical panel and joint areas of the nacelle had adequate structural integrity.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135075 , R76AEG420
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  • 121
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    Quiet Clean Short-haul Experimental Engine (QCSEE) Over-The-Wing (OTW) boilerplate nacelle design report (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A summary of the mechanical design of the boiler plate nacelle for the QCSEE over the wing (OTW) engine is presented. The nacelle, which features a D-shaped nozzle/thrust reverser and interchangeable hard wall and acoustic panels, is utilized in the engine testing to establish the aerodynamic and acoustic requirements for nozzles and reversers of this type.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135168 , R77AEG300
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  • 122
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    Quiet Clean Short-haul Experimental Engine (QCSEE). Under-The-Wing (UTW) engine boilerplate nacelle test report, volume 1 (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The design and testing of high bypass geared turbofan engines with nacelles forming the propulsion systems for short haul passenger aircraft are considered. The test results demonstrate the technology required for externally blown flap aircraft for introduction into passenger service in the 1980's. The equipment tested is described along with the test facility and instrumentation. A chronological history of the test and a summary of results are given.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135249 , R77AEG2121-VOL-1
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  • 123
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    Quiet Clean Short-haul Experimental Engine (QCSEE). Aerodynamic and aeromechanical performance of a 50.8 cm (20 inch) diameter 1.34 PR variable pitch fan with core flow (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The fan aerodynamic and aeromechanical performance tests of the quiet clean short haul experimental engine under the wing fan and inlet with a simulated core flow are described. Overall forward mode fan performance is presented at each rotor pitch angle setting with conventional flow pressure ratio efficiency fan maps, distinguishing the performance characteristics of the fan bypass and fan core regions. Effects of off design bypass ratio, hybrid inlet geometry, and tip radial inlet distortion on fan performance are determined. The nonaxisymmetric bypass OGV and pylon configuration is assessed relative to both total pressure loss and induced circumferential flow distortion. Reverse mode performance, obtained by resetting the rotor blades through both the stall pitch and flat pitch directions, is discussed in terms of the conventional flow pressure ratio relationship and its implications upon achievable reverse thrust. Core performance in reverse mode operation is presented in terms of overall recovery levels and radial profiles existing at the simulated core inlet plane. Observations of the starting phenomena associated with the initiation of stable rotor flow during acceleration in the reverse mode are briefly discussed. Aeromechanical response characteristics of the fan blades are presented as a separate appendix, along with a description of the vehicle instrumentation and method of data reduction.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135017 , R75AEG445
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  • 124
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    Quiet Clean Short-haul Experimental Engine (QCSEE). Composite fan frame subsystem test report (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The element and subcomponent testing conducted to verify the composite fan frame design of two experimental high bypass geared turbofan engines and propulsion systems for short haul passenger aircraft is described. Emphasis is placed on the propulsion technology required for future externally blown flap aircraft with engines located both under the wing and over the wing, including technology in composite structures and digital engine controls. The element tests confirmed that the processes used in the frame design would produce the predicted mechanical properties. The subcomponent tests verified that the detail structural components of the frame had adequate structural integrity.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135010 , R76AEG233
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  • 125
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    Quiet Clean Short-haul Experimental Engine (QCSEE) over-the-wing control system design report (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A control system incorporating a digital electronic control was designed for the over-the-wing engine. The digital electronic control serves as the primary controlling element for engine fuel flow and core compressor stator position. It also includes data monitoring capability, a unique failure indication and corrective action feature, and optional provisions for operating with a new type of servovalve designed to operate in response to a digital-type signal and to fail with its output device hydraulically locked into position.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135337 , R77AEG664
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    NASA TECHNICAL REPORTS
  • 126
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    Quiet Clean Short-haul Experimental Engine (QCSEE). Core engine noise measurements (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Noise measurements were taken on a turbofan engine which uses the same core, with minor modifications, employed on the quiet clean short-haul experimental engine (QCSEE) propulsion systems. Both nearfield and farfield noise measurements were taken in order to determine the core internally generated noise levels. The resulting noise measurements were compared to predicted combustor and turbine noise levels, to verify or improve the predicted QCSEE combustor and turbine noise levels.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135160 , R75AEG511
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  • 127
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    Quiet Clean Short-haul Experimental Engine (QCSEE). Under-The-Wing (UTW) engine boilerplate nacelle test report. Volume 3: Mechanical performance (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Results of initial tests of the under the wing experimental engine and boilerplate nacelle are presented. The mechanical performance of the engine is reported with emphasis on the advanced technology components. Technology elements of the propulsion system covered include: system dynamics, composite fan blades, reduction gear, lube and accessory drive system, fan frame, inlet, core cowl cooling, fan exhaust nozzle, and digital control system.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135251 , R77AEG212-VOL-3
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  • 128
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    Quiet Clean Short-haul Experimental Engine (QCSEE) preliminary over-the-wing flight propulsion system analysis report (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The preliminary design of the over-the-wing flight propulsion system installation and nacelle component and systems design features of a short-haul, powered lift aircraft are presented. Economic studies are also presented and show that high bypass, low pressure ratio turbofan engines have the potential of providing an economical propulsion system for achieving the very quiet aircraft noise level of 95 EPNdB on a 152.4 m sideline.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135296 , R77AEG305
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  • 129
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    Quiet Clean Short-haul Experimental Engine (QCSEE) under-the-wing engine simulation report (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Hybrid computer simulations of the under-the-wing engine were constructed to develop the dynamic design of the controls. The engine and control system includes a variable pitch fan and a digital electronic control. Simulation results for throttle bursts from 62 to 100 percent net thrust predict that the engine will accelerate 62 to 95 percent net thrust in one second.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134914 , R75AEG444
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  • 130
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    Quiet Clean Short-Haul Experimental Engine (QCSEE). Under-the-wing (UTW) engine boilerplate Nacelle test report. Volume 2: Aerodynamics and performance (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The initial phase of testing of the under the wing engine and boilerplate nacelle components is discussed. The aerodynamics and performance are outlined.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135250 , R77AEG2122-VOL-2
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  • 131
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    Method of fan sound mode structure determination computer program user's manual: Modal calculation program (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A computer user's manual describing the operation and the essential features of the Modal Calculation Program is presented. The modal Calculation Program calculates the amplitude and phase of modal structures by means of acoustic pressure measurements obtained from microphones placed at selected locations within the fan inlet duct. In addition, the Modal Calculation Program also calculates the first-order errors in the modal coefficients that are due to tolerances in microphone location coordinates and inaccuracies in the acoustic pressure measurements.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135295 , PWA-5554-5
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  • 132
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    Method of fan sound mode structure determination computer program user's manual: Microphone location program (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A computer user's manual describing the operation and the essential features of the microphone location program is presented. The Microphone Location Program determines microphone locations that ensure accurate and stable results from the equation system used to calculate modal structures. As part of the computational procedure for the Microphone Location Program, a first-order measure of the stability of the equation system was indicated by a matrix 'conditioning' number.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135294 , PWA-5554-4
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  • 133
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    Method of fan sound mode structure determination (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A method for the determination of fan sound mode structure in the Inlet of turbofan engines using in-duct acoustic pressure measurements is presented. The method is based on the simultaneous solution of a set of equations whose unknowns are modal amplitude and phase. A computer program for the solution of the equation set was developed. An additional computer program was developed which calculates microphone locations the use of which results in an equation set that does not give rise to numerical instabilities. In addition to the development of a method for determination of coherent modal structure, experimental and analytical approaches are developed for the determination of the amplitude frequency spectrum of randomly generated sound models for use in narrow annulus ducts. Two approaches are defined: one based on the use of cross-spectral techniques and the other based on the use of an array of microphones.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135293 , PWA-5554-3
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  • 134
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    Optimization study for high speed radial turbine with special reference to design variables (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Numerical results of a theoretical investigation are presented to provide information about the effect of variation of the different design and operating parameters on radial inflow turbine performance. The effects of variations in the mass flow rate, rotor tip Mach number, inlet flow angles, number of rotor blades and hub to shroud radius ratio, on the internal fluid dynamics of turbine rotors, was investigated. A procedure to estimate the flow deviation angles at the turbine exit is also presented and used to examine the influence of the operating conditions and the rotor geometrical configuration on these deviations. The significance of the results obtained is discussed with respect to improved turbine performance.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-152094
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  • 135
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    An analysis of the rotor blade stresses of the three stage compressor of the Ames Research Center 11- by 11-foot transonic wind tunnel (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The static and dynamic rotor blade stresses of the three stage compressor were measured. Data are presented in terms of total blade stress for the complete operational range of compressor speeds and tunnel total pressures. Modal frequencies and variations with tunnel conditions were measured. Phase angles and coherences between various gage combinations are also presented. Recommendations for improvements are given for future rotor blade experimental investigations.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-152083
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  • 136
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    Experimental clean combustor program: Turbulence characteristics of compressor discharge flows (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The results of turbulence measurements at the entrance to the diffuser duct of a large gas turbine are presented. Hot film and hot wire measurements were conducted over a compressor discharge temperature range of 450K to 608K. It was found that the turbulent intensity at the I.D. and midspan locations increases gradually from 6 + or - 1 percent at idle to 7 + or - 1 percent at approach; the turbulent intensity at the O.D. location increases from 7.5 + or - 0.5 percent at idle to 15 + or - 0.5 percent at approach. The energy in the velocity waves is uniformly distributed over a 0.1 to 5 kHz bandwidth, and the cut-off frequency is not a strong function of the engine operation. The axial length of the Fourier components within this bandwidth varies from 0.021 to 1.05m. The turbulence near the diffuser O.D. is of sufficient amplitude and scale to affect the flow to the front end sections of the burner.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135277 , PWA-5540
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  • 137
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    Computer Program for Calculation of a Gas Temperature Profile by Infrared Emission: Absorption Spectroscopy (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A computer program to calculate the temperature profile of a flame or hot gas was presented in detail. Emphasis was on profiles found in jet engine or rocket engine exhaust streams containing H2O or CO2 radiating gases. The temperature profile was assumed axisymmetric with an assumed functional form controlled by two variable parameters. The parameters were calculated using measurements of gas radiation at two wavelengths in the infrared. The program also gave some information on the pressure profile. A method of selection of wavelengths was given that is likely to lead to an accurate determination of the parameters. The program is written in FORTRAN IV language and runs in less than 60 seconds on a Univac 1100 computer.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-73848 , E-9436
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  • 138
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    Influence of oil-squeeze-film damping on steady-state response of flexible rotor operating to supercritical speeds (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Experimental data were obtained for the unbalance response of a flexible rotor to speeds above the third lateral bending critical. Squeeze-film damping coefficients calculated from measured data showed good agreement with short-journal-bearing approximations over a frequency range from 5000 to 31,000 cmp. Response of a rotor to varying amounts of unbalance was investigated. A very lightly damped rotor was compared with one where oil-squeeze dampers were applied.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-1094 , E-9091
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  • 139
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    Mechanical characteristics of stability-bleed valves for a supersonic inlet (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Mechanical characteristics of a set of direct-operated relief valves used in a throat-bypass stability-bleed system designed for the YF-12 aircraft inlet are described. A comparison of data taken before and after the windtunnel tests (at room temperature) showed that both the effective spring rate and the piston friction had decreased during the wind tunnel tests. In neither the effective spring rate nor the piston friction was the magnitude of change great enough to cause significant impairment of overall system effectiveness. No major valve mechanical problems were encountered in any of the tests. During high temperature bench tests, piston frictional drag increased. The friction returned to its initial room temperature value when the stability-bleed valve was disassembled and reassembled. The problem might be solved by using a different material for the piston sleeve bearing and the piston rings.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-3483 , E-8852
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  • 140
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    High frequency dynamic engine simulation (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A digital computer simulation of a mixed flow, twin spool turbofan engine was assembled to evaluate and improve the dynamic characteristics of the engine simulation to disturbance frequencies of at least 100 Hz. One dimensional forms of the dynamic mass, momentum and energy equations were used to model the engine. A TF30 engine was simulated so that dynamic characteristics could be evaluated against results obtained from testing of the TF30 engine at the NASA Lewis Research Center. Dynamic characteristics of the engine simulation were improved by modifying the compression system model. Modifications to the compression system model were established by investigating the influence of size and number of finite dynamic elements. Based on the results of this program, high frequency engine simulations using finite dynamic elements can be assembled so that the engine dynamic configuration is optimum with respect to dynamic characteristics and computer execution time. Resizing of the compression systems finite elements improved the dynamic characteristics of the engine simulation but showed that additional refinements are required to obtain close agreement simulation and actual engine dynamic characteristics.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135313 , PWA-5543
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  • 141
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    Advanced supersonic propulsion study, phases 3 and 4 (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An evaluation of various advanced propulsion concepts for supersonic cruise aircraft resulted in the identification of the double-bypass variable cycle engine as the most promising concept. This engine design utilizes special variable geometry components and an annular exhaust nozzle to provide high take-off thrust and low jet noise. The engine also provides good performance at both supersonic cruise and subsonic cruise. Emission characteristics are excellent. The advanced technology double-bypass variable cycle engine offers an improvement in aircraft range performance relative to earlier supersonic jet engine designs and yet at a lower level of engine noise. Research and technology programs required in certain design areas for this engine concept to realize its potential benefits include refined parametric analysis of selected variable cycle engines, screening of additional unconventional concepts, and engine preliminary design studies. Required critical technology programs are summarized.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135236 , R77AEG635
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  • 142
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    Augmentor emissions reduction technology program (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Technology to reduce pollutant emissions from duct-burner-type augmentors for use on advanced supersonic cruise aircraft was investigated. Test configurations, representing variations of two duct-burner design concepts, were tested in a rectangular sector rig at inlet temperature and pressure conditions corresponding to takeoff, transonic climb, and supersonic cruise flight conditions. Both design concepts used piloted flameholders to stabilize combustion of lean, premixed fuel/air mixtures. The concepts differed in the flameholder type used. High combustion efficiency (97%) and low levels of emissions (1.19 g/kg fuel) were achieved. The detailed measurements suggested the direction that future development efforts should take to obtain further reductions in emission levels and associated improvements in combustion efficiency over an increased range of temperature rise conditions.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135215 , R77AEG593
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  • 143
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    Effect of fuel properties on performance of single aircraft turbojet combustor at simulated idle, cruise, and takeoff conditions (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The performance of a single-can JT8D combustor was investigated with a number of fuels exhibiting wide variations in chemical composition and volatility. Performance parameters investigated were combustion efficiency, emissions of CO, unburned hydrocarbons and nitrogen oxides, as well as liner temperatures and smoke. The most pronounced effects of changes in fuel composition were observed at simulated cruise and takeoff conditions where smoke and liner temperatures increased significantly as the hydrogen content of the fuel decreased. At the simulated idle condition, emissions of CO and unburned hydrocarbons increased slightly and, accordingly, combustion efficiencies decreased slightly as the hydrogen content of the fuels decreased.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-73780 , E-9336
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  • 144
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    ENGINEL: A single rotor turbojet engine cycle match performance program (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: ENGINEL is a computer program which was developed to generate the design and off-design performance of a single rotor turbojet engine with or without afterburning using a cycle match procedure. It is capable of producing engine performance over a wide range of altitudes and Mach numbers. The flexibility, of operating with a variable geometry turbine, for improved off-design fuel consumption or with a fixed geometry turbine as in conventional turbojets, has been incorporated. In addition, the option of generation engine performance with JP4, liquid hydrogen or methane as fuel is provided.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-145267
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  • 145
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    Evaluation of a low aspect ratio small axial compressor stage, volume 2 (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: For abstract, see N78-12081.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135241 , PWA-FR-8499-VOL-2
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  • 146
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    Cost/benefit analysis of advanced material technologies for small aircraft turbine engines (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Cost/benefit studies were conducted on ten advanced material technologies applicable to small aircraft gas turbine engines to be produced in the 1985 time frame. The cost/benefit studies were applied to a two engine, business-type jet aircraft in the 6800- to 9100-Kg (15,000- to 20,000-lb) gross weight class. The new material technologies are intended to provide improvements in the areas of high-pressure turbine rotor components, high-pressure turbine rotor components, high-pressure turbine stator airfoils, and static structural components. The cost/benefit of each technology is presented in terms of relative value, which is defined as a change in life cycle cost times probability of success divided by development cost. Technologies showing the most promising cost/benefits based on relative value are uncooled single crystal MAR-M 247 turbine blades, cooled DS MAR-M 247 turbine blades, and cooled ODS 'M'CrAl laminate turbine stator vanes.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135265 , AIRESEARCH-21-2391 , RADC-TR-77-216
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  • 147
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    Evaluation of a low aspect ratio small axial compressor stage, volume 1 (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A program was conducted to evaluate the effects of scaling, tip clearance, and IGV reset on the performance of a low aspect ratio compressor stage. Stage design was obtained by scaling an existing single stage compressor by a linear factor of 0.304. The design objective was to maintain the meanline velocity field of the base machine in the smaller size. Adjustments were made to account for predicted blockage differences and to chord lengths and airfoil edge radii to obtain reasonable blade geometries. Meanline velocity diagrams of the base stage were not maintained at the scaled size. At design speed and flowrate the scaled stage achieved a pressure ratio of 1.423, adiabatic efficiency of 0.822, and surge margin of 18.5%. The corresponding performance parameters for the base stage were 1.480, 0.872, and 25.2%, respectively. The base stage demonstrated a peak efficiency at design speed of 0.872; the scaled stage achieved a level of 0.838. When the scaled stage rotor and stator tip clearances were doubled, the stage achieved a pressure ratio of 1.413, efficiency of 0.799, and surge margin of 16.0% at the design flowrate. The peak stage efficiency at design speed was 0.825 with the increased clearance. Increased prewhirl lowered the stage pressure ratio as expected. Stage efficiency was maintained with ten degrees of increased prewhirl and then decreased substantially with ten additional degrees of reset.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135240 , PWA-FR-8499-VOL-1
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  • 148
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    Altitude test of several afterburner configurations on a turbofan engine with a hydrogen heater to simulate an elevated turbine discharge temperature (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A performance test of several experimental afterburner configurations was conducted with a mixed-flow turbofan engine in an altitude facility. The simulated flight conditions were for Mach 1.4 at two altitudes, 12,190 and 14,630 meters. Turbine discharge temperatures of 889 and 1056 K were used. A production afterburner was tested for comparison. The research afterburners included partial forced mixers with V-gutter flameholders, a carburetted V-gutter flameholder, and a triple ring V-gutter flameholder with four swirl-can fuel mixers. Fuel injection variations were included. Performance data shown include augmented thrust ratio, thrust specific fuel consumption, combustion efficiency, and total pressure drop across the afterburner.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-1068 , E-9207
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  • 149
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    Effect of forward motion on engine noise (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Methods used to determine a procedure for correcting static engine data for the effects of forward motion are described. Data were analyzed from airplane flyover and static-engine tests with a JT8D-109 low-bypass-ratio turbofan engine installed on a DC-9-30, with a CF6-6D high-bypass-ratio turbofan engine installed on a DC-10-10, and with a JT9D-59A high-bypass-ratio turbofan engine installed on a DC-10-40. The observed differences between the static and the flyover data bases are discussed in terms of noise generation, convective amplification, atmospheric propagation, and engine installation. The results indicate that each noise source must be adjusted separately for forward-motion and installation effects and then projected to flight conditions as a function of source-path angle, directivity angle, and acoustic range relative to the microphones on the ground.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134954 , MDC-J7708
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  • 150
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    Integrated gas turbine engine-nacelle (1977)
    In:  CASI
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    Publication Date: 2019-06-27
    Description: A nacelle for use with a gas turbine engine is presented. An integral webbed structure resembling a spoked wheel for rigidly interconnecting the nacelle and engine, provides lightweight support. The inner surface of the nacelle defines the outer limits of the engine motive fluid flow annulus while the outer surface of the nacelle defines a streamlined envelope for the engine.
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  • 151
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    JT9D engine diagnostics. Task 2: Feasibility study of measuring in-service flight loads (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The feasibility of measuring JT9D propulsion system flight inertia loads on a 747 airplane is studied. Flight loads background is discussed including the current status of 747/JT9D loads knowledge. An instrumentation and test plan is formulated for an airline-owned in-service airplane and the Boeing-owned RA001 test airplane. Technical and cost comparisons are made between these two options. An overall technical feasibility evaluation is made and a cost summary presented. Conclusions and recommendations are presented in regard to using existing inertia loads data versus conducting a flight test to measure inertia loads.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135395 , D6-44664
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  • 152
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    Analysis of the cross flow in a radial inflow turbine scroll (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Equations of motion were derived, and a computational procedure is presented, for determining the nonviscous flow characteristics in the cross-sectional planes of a curved channel due to continuous mass discharge or mass addition. An analysis was applied to the radial inflow turbine scroll to study the effects of scroll geometry and the through flow velocity profile on the flow behavior. The computed flow velocity component in the scroll cross-sectional plane, together with the through flow velocity profile which can be determined in a separate analysis, provide a complete description of the three dimensional flow in the scroll.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135320
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  • 153
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    Evaluation of Federal Aviation Administration ion engine exhaust sampling rake (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A FAA exhaust emissions rake was tested in the Experimental Clean Combustor Program, Phase 3 to permit comparison of the values of gaseous emissions and smoke measured by the FAA rake with those measured with the NASA Pratt and Whitney Aircraft (P and WA) rake used in the Phase 3 Experimental Clean Combustor Program and with station seven probes. The results showed that the levels of CO, THC, NOx and smoke measured by the FAA and NASA/P and WA rakes agree well at high power, but that CO emissions measured by the FAA rake were approximately 10 percent higher than those measured by the NASA/P and WA rake at low power.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135213 , PWA-5534 , FAA-RD-77-115 , AD-A133422
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  • 154
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    Review of problems in application of supersonic combustion (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The problem of air-breathing engines capable of flying at very high Mach numbers is described briefly. Possible performance of supersonic combustion ramjets is outlined briefly and the supersonic combustion process is described. Two mechanisms of combustion are outlined: one is supersonic combustion controlled by convection process, and the second is controlled by diffusion. The parameters related to the combustion process are discussed in detail. Data and analyses of reaction rates and mixing phenomena are represented; the flame mechanism is discussed, and experimental results are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Selected Papers on Advanced Design of Air Vehicles; p 13-30
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  • 155
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    Analysis of simple 2-D and 3-D metal structures subjected to fragment impact (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Theoretical methods were developed for predicting the large-deflection elastic-plastic transient structural responses of metal containment or deflector (C/D) structures to cope with rotor burst fragment impact attack. For two-dimensional C/D structures both, finite element and finite difference analysis methods were employed to analyze structural response produced by either prescribed transient loads or fragment impact. For the latter category, two time-wise step-by-step analysis procedures were devised to predict the structural responses resulting from a succession of fragment impacts: the collision force method (CFM) which utilizes an approximate prediction of the force applied to the attacked structure during fragment impact, and the collision imparted velocity method (CIVM) in which the impact-induced velocity increment acquired by a region of the impacted structure near the impact point is computed. The merits and limitations of these approaches are discussed. For the analysis of 3-d responses of C/D structures, only the CIVM approach was investigated.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Assessment of Technol. for Turbojet Engine Rotor Failures; p 151-215
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  • 156
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    Stalled and stall-free performance of axial-flow compressor stage with three inlet-guide-vane and stator-blade settings (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The performance of the first stage of a transonic, multistage compressor was mapped over a range of inlet-guide-vane and stator-blade settings. Both stall-free and deep-stall performance data were obtained. For the settings tested, as stall was encountered and flow was further reduced, a relatively sharp drop in pressure ratio occurred and was followed by a continuing but more gradual reduction in pressure ratio with reduced flow. The position of the stall line on the map of pressure ratio against equivalent weight flow was essentially unaffected over the range of inlet-guide-vane and stator-blade settings.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TN-D-8457 , E-8222
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  • 157
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    Single stage, low noise, advanced technology fan. Volume 4: Fan aerodynamics. Section 2: Overall and blade element performance data tabulations (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: For abstract, see N77-17060.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134893 , R76AEG566-VOL-4
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  • 158
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    Single-stage, low-noise, advanced technology fan. Volume 4: Fan aerodynamics. Section 1: Results and analysis (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Test results at design speed show fan total pressure ratio, weight flow, and adiabatic efficiency to be 2.2, 2.9, and 1.8% lower than design goal values. The hybrid acoustic inlet (which utilizes a high throat Mach number and acoustic wall treatment for noise suppression) demonstrated total pressure recoveries of 98.9% and 98.2% at takeoff and approach. Exhaust duct pressure losses differed between the hardwall duct and treated duct with splitter by about 0.6% to 2.0% in terms of fan exit average total pressure (depending on operating condition). When the measured results were used to estimate pressure losses, a cruise sfc penalty of 0.68%, due to the acoustically treated duct, was projected.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134892 , R76AEG565-VOL-4
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  • 159
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    Oil cooling system for a gas turbine engine (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A gas turbine engine fuel delivery and control system is provided with means to recirculate all fuel in excess fuel control requirements back to the aircraft fuel tank. This increases the fuel pump heat sink and decreases the pump temperature rise without the addition of valving other than normally employed. A fuel/oil heat exchanger and associated circuitry is provided to maintain the hot engine oil in heat exchange relationship with the cool engine fuel. Where anti-icing of the fuel filter is required, means are provided to maintain the fuel temperature entering the filter at or above a minimum level to prevent freezing thereof. In one embodiment, a divider valve is provided to take all excess fuel from either upstream or downstream of the fuel filter and route it back to the tanks, the ratio of upstream to downstream extraction being a function of fuel pump discharge pressure.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 160
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    Analysis of dynamic inlet distortion applied to a parallel compressor model (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An investigation of surge was conducted by using a parallel compressor model of the J85-13 compressor implement on an analog computer. Surges were initiated by various types of dynamic disturbances in inlet pressure. The compressor model was less sensitive to disturbances of short duration, high frequency, and long duration where the compressor discharge pressure could react. Adding steady distortion to dynamic disturbances reduced the amount of dynamic disturbance required to effect surge. Steady and unsteady distortions combined linearly to reduce surge margin.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-3522 , E-8979
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  • 161
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    A computationally fast one-dimensional diffusion-photochemistry model of SST wakes (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: A computational technique applicable to analysis of supersonic transport (SST) wake photochemistry and diffusion is presented. Sensitivity studies of SST effluent effects upon ozone depletion are facilitated by the computational rapidity of the method. The article compares results from other studies and predictions of some variables related to global NOx input. Results indicate that the NO/NO2 ratio in an SST wake at photochemical equilibrium is a sensitive function of photolysis rates.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA Journal; 15; Aug. 197
    Format: text
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  • 162
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    Computer program for the analysis of the cross flow in a radial inflow turbine scroll (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A computer program was used to solve the governing of the potential flow in the cross sectional planes of a radial inflow turbine scroll. A list of the main program, the subroutines, and typical output example are included.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135321
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  • 163
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    Cost benefit study of advanced materials technology for aircraft turbine engines (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The cost/benefits of eight advanced materials technologies were evaluated for two aircraft missions. The overall study was based on a time frame of commercial engine use of the advanced material technologies by 1985. The material technologies evaluated were eutectic turbine blades, titanium aluminide components, ceramic vanes, shrouds and combustor liners, tungsten composite FeCrAly blades, gamma prime oxide dispersion strengthened (ODS) alloy blades, and no coat ODS alloy combustor liners. They were evaluated in two conventional takeoff and landing missions, one transcontinental and one intercontinental.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135235
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  • 164
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    Advanced supersonic propulsion study, phase 4 (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Installation characteristics for a Variable Stream Control Engine (VSCE) were studied for three advanced supersonic airplane designs. Sensitivity of the VSCE concept to change in technology projections was evaluated in terms of impact on overall installed performance. Based on these sensitivity results, critical technology requirements were reviewed, resulting in the reaffirmation of the following requirements: low-noise nozzle system; a high performance, low emissions duct burner and main burner; hot section technology; variable geometry components; and propulsion integration features, including an integrated electronic control system.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135273 , PWA-5547-4
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  • 165
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    Rotor burst protection program: Experimentation to provide guidelines for the design of turbine rotor burst fragment containment rings (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Empirical guidelines for the design of minimum weight turbine rotor disk fragment containment rings made from a monolithic metal were generated by experimentally establishing the relationship between a variable that provides a measure of containment ring capability and several other variables that both characterized the configurational aspects of the rotor fragments and containment ring, and had been found from exploratory testing to have had significant influence on the containment process. Test methodology and data analysis techniques are described. Results are presented in graphs and tables.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: MIT An Assessment of Technol. for Turbojet Engine Rotor Failures; p 107-149
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  • 166
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    An investigation of temperature distribution in cooled guide vanes (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A numerical study to determine the temperature distribution in the guide vane blades of a radial inflow turbine is presented. A computer program was developed which permits the temperature distribution to be calculated when the blade is cooled internally using a combination of impingement and film cooling techniques. The study is based on the use of the finite difference method in a two dimensional heat conduction problem. The results are then compared to determine the best cooling configuration for a certain coolant to primary mass flow ratio.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-152048
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  • 167
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    Identification of Spey engine dynamics in the augmentor wing jet STOL research aircraft from flight data (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The development and validation of a spey engine model is described. An analysis of the dynamical interactions involved in the propulsion unit is presented. The model was reduced to contain only significant effects, and was used, in conjunction with flight data obtained from an augmentor wing jet STOL research aircraft, to develop initial estimates of parameters in the system. The theoretical background employed in estimating the parameters is outlined. The software package developed for processing the flight data is described. Results are summarized.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-152054
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  • 168
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    Noise characteristics of upper surface blown configurations. Experimental program and results (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An experimental data base was developed from the model upper surface blowing (USB) propulsive lift system hardware. While the emphasis was on far field noise data, a considerable amount of relevant flow field data were also obtained. The data were derived from experiments in four different facilities resulting in: (1) small scale static flow field data; (2) small scale static noise data; (3) small scale simulated forward speed noise and load data; and (4) limited larger-scale static noise flow field and load data. All of the small scale tests used the same USB flap parts. Operational and geometrical variables covered in the test program included jet velocity, nozzle shape, nozzle area, nozzle impingement angle, nozzle vertical and horizontal location, flap length, flap deflection angle, and flap radius of curvature.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-145143 , LG77ER0198
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  • 169
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    Attenuation of upstream-generated low frequency noise by gas turbines (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The acoustic transfer functions of low frequency (below 3500 Hz) noise through aircraft turbines were investigated. Model test results were compared with theoretical predictions in order to assess the validity of the theory. Component tests were conducted on both high pressure and low pressure model turbines. The influence of inlet temperature and turbine speed attenuation was evaluated, while the effects of turbine pressure ratio, blade-row choking, and additional downstream stages were determined. Preliminary identification of pertinent aeroacoustic correlating parameters was made.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135219 , R77AEG482
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  • 170
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    Experimental investigation of a swept-strut fuel-injector concept for scramjet application (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Results are presented of an experiment to investigate the behavior at Mach 4 flight conditions of the swept-strut fuel-injector concept employed in the Langley integrated modular scramjet engine design. Autoignition of the hydrogen fuel was not achieved at stagnation temperatures corresponding to a flight Mach number of 4; however, once ignition was achieved, stable combustion was maintained. Pressure disturbances upstream of the injector location, which were caused by fuel injection and combustion, were generally not observed; this indicates the absence of serious adverse combustor-inlet interactions. Mixing performance and reaction performance determined from probe surveys and wall pressure data indicate that high combustion efficiency should be obtained with the combustor length provided in the scramjet engine design. No adverse interaction between the perpendicular and parallel fuel-injection modes was observed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TN-D-8454 , L-11050
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  • 171
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    Dual cycle aircraft turbine engine (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A method and apparatus are presented for improving operating efficiency over broad ranges of flight conditions and for reducing jet engine noise output in takeoff and landing by controlling the airflow entering and exiting the engines. A turbojet engine apparatus is described which operates efficiently at both subsonic and supersonic speeds and a method is described which enables a turbofan with an associated satellite turbojet or turbofan to operate more efficiently at both subsonic and supersonic speeds. In both cases, takeoff and landing noise is reduced substantially. The apparatus consists essentially of arranging for two separate portions of an engine to act upon one airstream or, alternately, to operate on independent airstreams.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 172
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    Analysis and documentation of QCSEE (Quiet Clean Short-haul Experimental Engine) over-the-wing exhaust system development (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A static scale model test program was conducted in the static test area of the NASA-Langley 9.14- by 18.29 m(30- by 60-ft) Full-Scale Wind Tunnel Facility to develop an over-the-wing (OTW) nozzle and reverser configuration for the Quiet Clean Short-Haul Experimental Engine (QCSEE). Three nozzles and one basic reverser configuration were tested over the QCSEE takeoff and approach power nozzle pressure ratio range between 1.1 and 1.3. The models were scaled to 8.53% of QCSEE engine size and tested behind two 13.97-cm (5.5-in.) diameter tip-turbine-driven fan simulators coupled in tandem. An OTW nozzle and reverser configuration was identified which satisfies the QCSEE experimental engine requirements in terms of nozzle cycle area variation capability and reverse thrust level, and provides good jet flow spreading over a wing upper surface for achievement of high propulsive lift performance.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-2792 , R76AEG407
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  • 173
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    Preliminary study of a hydrogen peroxide rocket for use in moving source jet noise tests (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A preliminary investigation was made of using a hydrogen peroxide rocket to obtain pure moving source jet noise data. The thermodynamic cycle of the rocket was analyzed. It was found that the thermodynamic exhaust properties of the rocket could be made to match those of typical advanced commercial supersonic transport engines. The rocket thruster was then considered in combination with a streamlined ground car for moving source jet noise experiments. When a nonthrottlable hydrogen peroxide rocket was used to accelerate the vehicle, propellant masses and/or acceleration distances became too large. However, when a throttlable rocket or an auxiliary system was used to accelerate the vehicle, reasonable propellant masses could be obtained.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-73678 , E-9210
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  • 174
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    Blade retainer assembly (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A retaining assembly is provided for locking radially extending blades in a rotor disc associated with a gas turbine engine. The assembly includes a pair of spaced apart lugs axially extending from one side of the disc to form an access gap for insertion of a blade tang into a dovetail slot in the rotor disc. A pair of axially aligned inwardly facing recesses are disposed in the lugs. A retaining member resides in the recesses and extends across the gap to preclude egress of the blade tang from the dovetail slot. The retaining member includes at least one axially extending protrusion adapted to radially overlap and abuttingly engage a radially inwardly facing abutment surface on the lugs.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 175
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    Preliminary design of propulsion system for V/STOL research and technology aircraft (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The V/STOL Research and Technology Aircraft (RTA)propulsion system design effort is limited to components of the lift/cruise engines, turboshaft engine modifications, lift fan assembly, and propulsion system performance generation. The uninstalled total net thrust with all engines and fans operating at intermediate power was 37,114 pounds. Uninstalled system total net thrust was 27,102 pounds when one lift/cruise is inoperative. Components have lives above the 500 hours of the RTA duty cycle. The L/C engine used in a fixed nacelle has the cross shaft forward of the reduction gear whereas the cross shaft is aft of the reduction gear in a tilt nacelle L/C engine. The lift/cruise gearbox contains components and technologies from other DDA engines. The rotor has a 62-inch diameter and contains 22 composite blades that have a hub/tip ratio of 0.454. The blade pitch change mechanism contains hydraulic and mechanical redundancy. The lift fan assembly is completely self-contained including oil cooling in 10 exit vanes.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135207 , DDA-EDR-9082
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  • 176
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    Static and wind tunnel near-field/far-field jet noise measurements from model scale single-flow base line and suppressor nozzles. Summary report (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A test program was conducted in the Boeing large anechoic test chamber and the NASA-Ames 40- by 80-foot wind tunnel to study the near- and far-field jet noise characteristics of six baseline and suppressor nozzles. Static and wind-on noise source locations were determined. A technique for extrapolating near field jet noise measurements into the far field was established. It was determined if flight effects measured in the near field are the same as those in the far field. The flight effects on the jet noise levels of the baseline and suppressor nozzles were determined. Test models included a 15.24-cm round convergent nozzle, an annular nozzle with and without ejector, a 20-lobe nozzle with and without ejector, and a 57-tube nozzle with lined ejector. The static free-field test in the anechoic chamber covered nozzle pressure ratios from 1.44 to 2.25 and jet velocities from 412 to 594 m/s at a total temperature of 844 K. The wind tunnel flight effects test repeated these nozzle test conditions with ambient velocities of 0 to 92 m/s.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-2841 , D6-44121-3
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  • 177
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    Static, noise, and transition tests of a combined-surface-blowing V/STOL lift/propulsion system (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Efficient thrust vectoring and high levels of circulatory lift were obtained in tests of a half model V/STOL airplane by using a type of externally blown jet flap in which the jet exhaust from wing-mounted cruise fans is directed over both upper and lower surfaces of a flapped wing. Approximately 90% thrust recovery with 87 deg of thrust vectoring was achieved under static conditions using 89 deg of trailing edge flap deflection. The approximately 10% loss appears to be associated primarily with pressure losses due to the flap brackets or slot entries. The jet induced lift was shown to be 55% of the theoretical value for a fullspan jet-flapped wing, even though only 27.5% of the wingspan was immersed in the jet. Steady rate of descent capability in excess of 1,000 feet per minute is predicted. The possibility of significant aerodynamic-noise cancelling when blowing over both surfaces at high velocities is indicated.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-151954 , D210-11175-1
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  • 178
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    Boron/aluminum fan blades for SCAR engines (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Processing procedures were developed to enhance boron/aluminum bond behavior and foreign object damage (FOD) tolerance. Design and analysis indicated that the J101 Stage 1 fan blade meets the required frequencies without a midspan shroud. The fabricability of full size J101 blades was assessed, while six blades were fabricated and finished machined.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135184
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  • 179
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    Experimental apparatus for investigation of fan aeroelastic instabilities in turbomachinery (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The application, installation, and monitoring of dynamic strain gage instrumentation on the rotating fan blades for subsonic stalled flutter mode of the first fan rotor are described. The engine installation, the modifications to the engine controls to obtain off schedule operation of the fan, engine aerodynamic instrumentation, and general data acquisition systems are discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-3508 , E-9088
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  • 180
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    A method to estimate weight and dimensions of aircraft gas turbine engines. Volume 3: Programmer's manual (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: For abstract, see N77-25171.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135172 , D6-44258-VOL-3
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  • 181
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    A method to estimate weight and dimensions of aircraft gas turbine engines. Volume 2: User's manual (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: For abstract, see N77-25171.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135171 , D6-44258-VOL-2
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  • 182
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    A method to estimate weight and dimensions of aircraft gas turbine engines. Volume 1: Method of analysis (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Weight and envelope dimensions of aircraft gas turbine engines are estimated within plus or minus 5% to 10% using a computer method based on correlations of component weight and design features of 29 data base engines. Rotating components are estimated by a preliminary design procedure where blade geometry, operating conditions, material properties, shaft speed, hub-tip ratio, etc., are the primary independent variables used. The development and justification of the method selected, the various methods of analysis, the use of the program, and a description of the input/output data are discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135170 , D6-44258-VOL-1
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  • 183
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    Noise of fan designed to reduce stator lift fluctuations (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An existing fan stage was redesigned to reduce stator lift fluctuations and was acoustically tested at three nozzle sizes for reduced noise generation. The lift fluctuations on the stator were reduced by increasing the stator cord, adjusting incidence angles, and adjusting the rotor velocity diagrams. Broadband noise levels were signficantly reduced in the middle to high frequencies. Blade passage tone sound power was not lessened, but decreases in the harmonics were observed. Aerodynamic improvements in both performance and efficiency were obtained.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-3538 , E-8986
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  • 184
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    Performance of high-area-ratio annular dump diffuser using suction-stabilized-vortex flow control (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A short annular dump diffuser having a geometry conductive to formation of suction stabilized toroidal vortices in the region of abrupt area change was tested. The overall diffuser area ratio was 4.0 and the length to inlet height ratio was 2.0. Performance data were obtained at near ambient temperature and pressure for inlet Mach numbers of 0.18 and 0.30 with suction rates ranging from 0 to 18 percent of total inlet mass flowrate. Results show that the exit velocity profile could be readily biased toward either wall by adjustment of inner and outer wall suction rates. Symmetric exit velocity profiles were inherently unstable with a tendency to revert to a hub or tip bias. Diffuser effectiveness was increased from about 38 percent without suction to over 85 percent at a total suction rate of 10 to 12 percent. At the same time diffuser total pressure loss was reduced from 3.1 percent to 1.1 percent at an inlet Mach number of 0.3.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-3535 , E-9011
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  • 185
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    Analytical prediction of the performance and stability of a J85-13 compressor with distorted inlet flow (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The parallel compressor concept was studied using a compressor model based on the overall clean-inlet performance map obtained from experimental tests in an altitude chamber using a General Electric J85-13 turbojet engine. The model, which includes a static-pressure balance calculation at compressor discharge, was exercised at conditions corresponding to 10 different screen-induced distortion patterns included in the experimental data base. The spoiled area of these patterns ranged from 30 deg to 180 deg, and the distortion screen density, or the area blocked by the screen wire per unit area of screen, varied from 26 to 69 percent. The study indicates that at the higher corrected speeds, the analytical surge lines obtained are good representations of the corresponding experimental surge lines and are independent of distortion angle or distortion angle or distortion level.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-3515 , E-8887
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  • 186
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    Inlet Reynolds number and temperature effects on the steady-state performance of a TFE731-2 turbofan engine (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Effects of varying engine inlet Reynolds number index (0.75, 0.50, 0.25, and 0.12) and temperature (289 and 244 K) on a TFE731-2 turbofan engine were evaluated. Results were classified as either compression system effects or effects on overall performance. Standard performance maps are used to present compression system performance. Overall performance parameters are presented as a function of low rotor speed corrected to engine inlet temperature.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-3537 , E-8941
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  • 187
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    Interior and exterior fuselage noise measured on NASA's C-8a augmentor wing jet-STOL research aircraft (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Interior and exterior fuselage noise levels were measured on NASA's C-8A Augmentor Wing Jet-STOL Research Aircraft in order to provide design information for the Quiet Short-Haul Research Aircraft (QSRA), which will use a modified C-8A fuselage. The noise field was mapped by 11 microphones located internally and externally in three areas: mid-fuselage, aft fuselage, and on the flight deck. Noise levels were recorded at four power settings varying from takeoff to flight idle and were plotted in one-third octave band spectra. The overall sound pressure levels of the external noise field were compared to previous tests and found to correlate well with engine primary thrust levels. Fuselage values were 145 + or - 3 dB over the aircraft's normal STOL operating range.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-73235 , A-7012
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  • 188
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    Preliminary studies of autoignition and flashback in a premixing-prevaporizing flame tube using Jet-A fuel at lean equivalence ratios (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Lean equivalence ratios from 0.3 to 0.7 were observed. Combustor inlet air pressures were varied from 0.54 to 2.5 MPa, combustor inlet air temperatures from 550 to 700 K, and reference velocities from 8 to 35 meters per second. Autoignition delay times ranged from 15 to 100 milliseconds and varied inversely with pressure. The Arrhenius activation energy was 41,840 joules per mole. Temperature rise data were obtained in a long premixing-prevaporizing tube at a pressure of 0.56 MPa. Preflame temperature rise data were a function of equivalence ratio, inlet air temperature, and tube residence time. Significant temperature rise occurred above temperatures of 760 K, with autoignition occurring at 775 K for equivalence ratios greater than 0.47. The reactions were similar to cool-flame phenomena. Flashback velocities were measured at temperatures of 610 and 700 K, pressure of 0.56 MPa, and equivalence ratios from 0.6 to 1. Flashback velocities varied from 30 to 65 meters per second.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-3526 , E-9039
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  • 189
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    Application of differential similarity to finding nondimensional groups important in tests of cooled engine components (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The method of differential similarity is applied to the partial differential equations and boundary conditions which govern the temperature, velocity, and pressure fields in the flowing gases and the solid stationary components in air-cooled engines. This procedure yields the nondimensional groups which must have the same value in both the test rig and the engine to produce similarity between the test results and the engine performance. These results guide the experimentalist in the design and selection of test equipment that properly scales quantities to actual engine conditions. They also provide a firm fundamental foundation for substantiation of previous similarity analyses which employed heuristic, physical reasoning arguments to arrive at the nondimensional groups.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-3484 , E-8943
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  • 190
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    Definition of propulsion system for V/STOL research and technology aircraft (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Wind tunnel test support, aircraft contractor support, a propulsion system computer card deck, preliminary design studies, and propulsion system development plan are reported. The Propulsion system consists of two lift/cruise turbofan engines, one turboshaft engine and one lift fan connected together with shafting into a combiner gearbox. Distortion parameter levels from 40 x 80 test data were within the established XT701-AD-700 limits. The three engine-three fan system card deck calculates either vertical or conventional flight performance, installed or uninstalled. Design study results for XT701 engine modifications, bevel gear cross shaft location, fixed and tilt fan frames and propulsion system controls are described. Optional water-alcohol injection increased total net thrust 10.3% on a 90 F day. Engines have sufficient turbine life for 500 hours of the RTA duty cycle.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135161 , EDR-9020
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  • 191
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    Numerical solution for the temperature distribution in a cooled guide vane blade of a radial gas turbine (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A two dimensional finite difference numerical technique is presented to determine the temperature distribution of an internal cooled blade of radial turbine guide vanes. A simple convection cooling is assumed inside the guide vane blade. Such cooling has relatively small cooling effectiveness at the leading edge and at the trailing edge. Heat transfer augmentation in these critical areas may be achieved by using impingement jets and film cooling. A computer program is written in FORTRAN IV for IBM 370/165 computer.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-137943
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  • 192
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    A numerical study of the temperature field in a cooled radial turbine rotor (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The three dimensional temperature distribution in the cooled rotor of a radial inflow turbine is determined numerically using the finite element method. Through this approach, the complicated geometries of the hot rotor and coolant passage surfaces are handled easily, and the temperatures are determined without loss of accuracy at these convective boundaries. Different cooling techniques with given coolant to primary flow ratios are investigated, and the corresponding rotor temperature fields are presented for comparison.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-137951
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  • 193
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    A study of the optimization method used in the NAVY/NASA gas turbine engine computer code (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Sources of numerical noise affecting the convergence properties of the Powell's Principal Axis Method of Optimization in the NAVY/NASA gas turbine engine computer code were investigated. The principal noise source discovered resulted from loose input tolerances used in terminating iterations performed in subroutine CALCFX to satisfy specified control functions. A minor source of noise was found to be introduced by an insufficient number of digits in stored coefficients used by subroutine THERM in polynomial expressions of thermodynamic properties. Tabular results of several computer runs are presented to show the effects on program performance of selective corrective actions taken to reduce noise.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135180 , AMA-77-1
    Format: application/pdf
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  • 194
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    Analytical screening of low emissions, high performance duct burners for supersonic cruise aircraft engines (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An analytical screening study was conducted to identify duct burner concepts capable of providing low emissions and high performance in advanced supersonic engines. Duct burner configurations ranging from current augmenter technology to advanced concepts such as premix-prevaporized burners were defined. Aerothermal and mechanical design studies provided the basis for screening these configurations using the criteria of emissions, performance, engine compatibility, cost, weight and relative risk. Technology levels derived from recently defined experimental low emissions main burners are required to achieve both low emissions and high performance goals. A configuration based on the Vorbix (Vortex burning and mixing) combustor concept was analytically determined to meet the performance goals and is consistent with the fan duct envelope of a variable cycle engine. The duct burner configuration has a moderate risk level compatible with the schedule of anticipated experimental programs.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135157 , PWA-5489
    Format: application/pdf
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  • 195
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    Ultra high tip speed (670.6 m/sec) fan stage with composite rotor: Aerodynamic and mechanical design (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A highly loaded, single-stage compressor having a tip speed of 670.6 m/sec was designed for the purpose of investigating very high tip speeds and high aerodynamic loadings to obtain high stage pressure ratios at acceptable levels of efficiency. The design pressure ratio is 2.8 at an adiabatic efficiency of 84.4%. Corrected design flow is 83.4 kg/sec; corrected design speed is 15,200 rpm; and rotor inlet tip diameter is 0.853 m. The rotor uses multiple-circular-arc airfoils from 0 to 15% span, precompression airfoils assuming single, strong oblique shocks from 21 to 43% span, and precompression airfoils assuming multiple oblique shocks from 52% span to the tip. Because of the high tip speeds, the rotor blades are designed to be fabricated of composite materials. Two composite materials were investigated: Courtaulds HTS graphite fiber in a Kerimid 601 polyimide matrix and the same fibers in a PMR polyimide matrix. In addition to providing a description of the aerodynamic and mechanical design of the 670.0 m/sec fan, discussion is presented of the results of structural tests of blades fabricated with both types of matrices.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135122 , PWA-5487
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  • 196
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    Detailed design of a quiet high flow fan (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A single stage fan was designed to demonstrate the noise abatement properties of near-sonic inlet flow and long-chord stator vanes for the reduction of both upstream and downstream propagated fan source noise. It is designed to produce a pressure ratio of 1.653:1 with an adiabatic efficiency of 83.9%. The fan has a 508 mm inlet diameter with a hub/tip ratio of 0.426 and a design tip speed of 533.4 m/sec. The design inlet specific flow rate is 219.71 kg/sec sq m and there are 10 tandem stator vanes with a combined aspect ratio of 0.54.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135126 , EDR-9071
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  • 197
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    Analysis of turbofan propulsion system weight and dimensions (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Weight and dimensional relationships that are used in aircraft preliminary design studies are analyzed. These relationships are relatively simple to prove useful to the preliminary designer, but they are sufficiently detailed to provide meaningful design tradeoffs. All weight and dimensional relationships are developed from data bases of existing and conceptual turbofan engines. The total propulsion system is considered including both engine and nacelle, and all estimating relations stem from physical principles, not statistical correlations.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-73199 , A-6890
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  • 198
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    Thrust reverser design studies for an over-the-wing STOL transport (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Aerodynamic and acoustics analytical studies were conducted to evaluate three thrust reverser designs for potential use on commercial over-the-wing STOL transports. The concepts were: (1) integral D nozzle/target reverser, (2) integral D nozzle/top arc cascade reverser, and (3) post exit target reverser integral with wing. Aerodynamic flowpaths and kinematic arrangements for each concept were established to provide a 50% thrust reversal capability. Analytical aircraft stopping distance/noise trade studies conducted concurrently with flow path design showed that these high efficiency reverser concepts are employed at substantially reduced power settings to meet noise goals of 100 PNdB on a 152.4 m sideline and still meet 609.6 m landing runway length requirements. From an overall installation standpoint, only the integral D nozzle/target reverser concept was found to penalize nacelle cruise performance; for this concept a larger nacelle diameter was required to match engine cycle effective area demand in reverse thrust.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-151958 , R77AEG190
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  • 199
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    The Influence of Forward Flight on Propeller Noise (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The effect of flight on blade surface pressures and propeller noise was reported. There were significant differences in blade surface pressures and far-field noise between static and flight conditions. The static data showed many high-intensity, tone-like peaks whereas the flight data was generally free from tones. The turbulence ingested by the propeller operating statically was dominated by long, thin eddies. In flight the scale of the turbulence was greately reduced from that observed statically.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-145105
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  • 200
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    Cold-air investigation of a 31/2-stage fan-drive turbine with a stage loading factor of 4 designed for an integral lift engine. 2: Performance of 2-, 3- and 3 1/2-stage configurations (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The stage work distribution among the three stages was very close to the design value. The specific work output-mass flow characteristics of the three stages were closely matched. The efficiency of the 3 1/2 stage turbine at design specific work output and design speed was within 0.008 of the estimated value, and this agreement was felt to demonstrate the adequacy of the prediction method in the high stage loading factor regime.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-3482 , E-8874
    Format: application/pdf
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