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  • 1
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    Atmospheric analysis for airdata calibration on research aircraft (1992)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: In-flight airdata calibrations are used to determine the aerodynamic influence of an airplane on pitot-static pressure measurements of altitude and speed. Conventional flight-test calibration techniques are briefly reviewed and meteorological analysis methods for estimating calibration reference values of atmospheric conditions are described. There are cases where some conventional in-flight techniques are not entirely satisfactory for research aircraft because of added equipment requirements or flight envelope and location limitations. In these cases, atmospheric wind and pressure information can be used to complement conventional techniques. Accuracy of the atmospheric measurements and the variability of upper-air winds and pressure values are discussed. Results from several flight research aircraft show that wind reference calibration is generally less accurate than calibration accuracy standards for civil and research aircraft. Examples of pressure reference altimetry derived from meteorological analyses are also presented for a variety of flight research programs. These flight data show that the reference pressure accuracy provided by meteorological analyses is usually within civil aircraft and flight research airdata calibration accuracy standards. Meteorological analyses altimetry is particularly useful when it is not feasible to restrict the test airplane altitude, location, or maneuver envelope.
    Keywords: AIRCRAFT INSTRUMENTATION
    Type: AIAA PAPER 92-0293
    Format: text
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    NASA TECHNICAL REPORTS
  • 2
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    Aerothermal test results from the second flight of the Pegasus booster (1992)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A survey of temperature, heat-flux, and pressure measurements was obtained at speeds through Mach 8.0 on the second flight of the Pegasus air-launched space booster system. All sensors were distributed on the wing-body fairing or fillet. Sensors included thin foil-gauge thermocouples installed near the surface within the thermal protection system. Thermocouples were also installed on the surface of nonablating plugs. The resulting temperature time history allowed derivation of convective heat flux. In addition, commercially available calorimeters were installed on the fillet at selected locations. Calorimeters exhibited a larger change in measured heat flux than collocated nonablating plugs in response to particular events. Similar proportional variations in heat flux across different regions of the fillet were detected by both the calorimeters and nonablating plugs. Pressure ports were installed on some nonablating plugs to explore the effects of port protrusion and high-frequency noise on pressure requirements. The effect of port protrusion on static-pressure measurements was found to decrease with increasing Mach number. High-frequency noise suppression was found to be desirable but not required on any future flight.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA-TM-4391 , H-1827 , NAS 1.15:4391
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    A system for testing airdata probes at high angles of attack using a ground vehicle (1991)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A system to calibrate airdata probes at angles of attack between 0 and 90 deg was developed and tested at the NASA Ames Dryden Flight Research Facility. This system used a test fixture mounted to the roof of a ground vehicle and included an onboard instrumentation and data acquisition system for measuring pressures and flow angles. The data could be easily transferred to the facility mainframe computer for further analysis. The system was designed to provide convenient and inexpensive airdata probe calibrations for projects which require airdata at high angles of attack, such as the F-18 High Alpha Research Program. This type of probe was tested to 90 deg angle of attack in a wind tunnel and using the ground vehicle system. The results of both tests are in close agreement. An airdata probe with a swiveling pilot-static tube was also calibrated with the ground vehicle system. This paper presents the results of these tests and gives a detailed description of the test system.
    Keywords: RESEARCH AND SUPPORT FACILITIES (AIR)
    Type: AIAA PAPER 91-0088
    Format: text
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  • 4
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    Aerothermal test results from the first flight of the Pegasus air-launched space booster (1991)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A survey of temperature measurements at speeds through Mach 8.0 on the first flight of the Pegasus air-launched booster system is discussed. In addition, heating rates were derived from the temperature data obtained on the fuselage in the vicinity of the wing shock interaction. Sensors were distributed on the wing surfaces, leading edge, and on the wing-body fairing or fillet. Side-by-side evaluations were obtained for a variety of sensor installations. Details of the trajectory reconstruction through first-stage separation are provided. Given here are indepth descriptions of the sensor installations, temperature measurements, and derived heating rates along with interpretations of the results.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA-TM-4330 , H-1672 , NAS 1.15:4330
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Airdata calibration of a high-performance aircraft for measuring atmospheric wind profiles (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The research airdata system of an instrumented F-104 aircraft has been calibrated to measure winds aloft in support of the Space Shuttle wind measurement investigation. The F-104 aircraft was equipped with a research pitot-static noseboom with integral angle-of-attack and flank angle-of-attack vanes and a ring-laser-gyro inertial reference unit. The F-104 aircraft and instrumentation configuration, flight test maneuvers, data corrections, calibration techniques, and resulting calibrations and data repeatability are presented. Recommendations for future airdata systems on aircraft used to measure winds aloft are also given.
    Keywords: AIRCRAFT INSTRUMENTATION
    Type: AIAA PAPER 90-0230
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  • 6
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    SCAMP: Rapid Focused Sonic Boom Waypoint Flight Planning Methods, Execution, and Results (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Successful execution of the flight phase of the Superboom Caustic Analysis and Measurement Project (SCAMP) required accurate placement of focused sonic booms on an array of prepositioned ground sensors. While the array was spread over a 10,000-ft-long area, this is a relatively small region when considering the speed of a supersonic aircraft and sonic boom ray path variability due to shifting atmospheric conditions and aircraft trajectories. Another requirement of the project was to determine the proper position for a microphone-equipped motorized glider to intercept the sonic boom caustic, adding critical timing to the constraints. Variability in several inputs to these calculations caused some shifts of the focus away from the optimal location. Reports of the sonic booms heard by persons positioned amongst the array were used to shift the focus closer to the optimal location for subsequent passes. This paper describes the methods and computations used to place the focused sonic boom on the SCAMP array and gives recommendations for their accurate placement by future quiet supersonic aircraft. For the SCAMP flights, 67% of the foci were placed on the ground array with measured positions within a few thousand feet of computed positions. Among those foci with large caustic elevation angles, 96% of foci were placed on the array, and measured positions were within a few hundred feet of computed positions. The motorized glider captured sonic booms on 59% of the passes when the instrumentation was operating properly.
    Keywords: Acoustics
    Type: DFRC-E-DAA-TN6916 , AIAA Aerospace Sciences Meeting; Dec 19, 2012 - Dec 21, 2012; Grapevine, TX; United States|Industry Panel Presentation at the University of Southern California; Nov 03, 2017; Los Angeles, CA; United States
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  • 7
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    The Effect of Sonic Booms on Earthquake Warning Systems (2011)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Several aerospace companies are designing quiet supersonic business jets for service over the United States. These aircraft have the potential to increase the occurrence of mild sonic booms across the country. This leads to interest among earthquake warning (EQW) developers and the general seismological community in characterizing the effect of sonic booms on seismic sensors in the field, their potential impact on EQW systems, and means of discriminating their signatures from those of earthquakes. The SonicBREWS project (Sonic Boom Resistant Earthquake Warning Systems) is a collaborative effort between Seismic Warning Systems, Inc. (SWS) and NASA Dryden Flight Research Center. This project aims to evaluate the effects of sonic booms on EQW sensors. The study consists of exposing high-sample-rate (1000 sps) triaxial accelerometers to sonic booms with overpressures ranging from 10 to 600 Pa in the free field and the built environment. The accelerometers record the coupling of the sonic boom to the ground and surrounding structures, while microphones record the acoustic wave above ground near the sensor. Sonic booms are broadband signals with more high-frequency content than earthquakes. Even a 1000 sps accelerometer will produce a significantly aliased record. Thus the observed peak ground velocity is strongly dependent on the sampling rate, and increases as the sampling rate is reduced. At 1000 sps we observe ground velocities that exceed those of P-waves from M〈sub〉L 〈/sub〉 3 earthquakes at local distances, suggesting that sonic booms are not negligible for EQW applications. We present the results of several experiments conducted under SonicBREWS showing the effects of typical-case low amplitude sonic booms and worst-case high amplitude booms. We show the effects of various sensor placements and sensor array geometries. Finally, we suggest possible avenues for discriminating sonic booms from earthquakes for the purposes of EQW.
    Keywords: Geosciences (General)
    Type: DFRC-E-DAA-TN3366 , Seismological Society of America''s Annual Meeting; Apr 13, 2011; Memphis, TX; United States
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    NASA TECHNICAL REPORTS
  • 8
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    High-Quality Seismic Observations of Sonic Booms (2011)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The SonicBREWS project (Sonic Boom Resistant Earthquake Warning Systems) is a collaborative effort between Seismic Warning Systems, Inc. and NASA Dryden Flight Research Center. This project aims to evaluate the effects of sonic booms on Earthquake Warning Systems in order to prevent such systems from experiencing false alarms due to sonic booms. The airspace above the Antelope Valley, California includes the High Altitude Supersonic Corridor and the Black Mountain Supersonic Corridor. These corridors are among the few places in the US where supersonic flight is permitted, and sonic booms are commonplace in the Antelope Valley. One result of this project is a rich dataset of high-quality accelerometer records of sonic booms which can shed light on the interaction between these atmospheric phenomena and the solid earth. Nearly 100 sonic booms were recorded with low-noise triaxial MEMS accelerometers recording 1000 samples per second. The sonic booms had peak overpressures ranging up to approximately 10 psf and were recorded in three flight series in 2010 and 2011. Each boom was recorded with up to four accelerometers in various array configurations up to 100 meter baseline lengths, both in the built environment and the free field. All sonic booms were also recorded by nearby microphones. We present the results of the project in terms of the potential for sonic-boom-induced false alarms in Earthquake Warning Systems, and highlight some of the interesting features of the dataset.
    Keywords: Geosciences (General)
    Type: DFRC-372 , S31D-2272 , DFRC-E-DAA-TN4480 , AGU Fall Meeting 2011; Dec 05, 2011 - Dec 09, 2011; San Francisco, CA; United States
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  • 9
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    Quiet Sonic Booms: A NASA and Industry Progress Report (2011)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: The purpose of this Oral Presentation is to present a progress report on NASA and Industry efforts related to Quiet Sonic Boom Program activities. This presentation will review changes in aircraft shaping to produce quiet supersonic booms and associated supersonic flight test methods and results. In addition, new flight test profiles have been recently developed that have allowed for the generation of sonic booms of varying intensity. These new flight test profiles have allowed for ground testing of the response of various building structures to sonic booms and the associated public acceptability to various sonic boom intensities. The new flight test profiles and associated ground measurement test methods will be reviewed. Finally, this Oral Presentation will review the International Regulatory requirements that would be involved to change aviation regulation and allow for overland quiet supersonic flight.
    Keywords: Acoustics
    Type: DFRC-E-DAA-TN3217 , 43rd European Symposium of the Society of Experimental; May 25, 2011; Venice; Italy
    Format: text
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    NASA TECHNICAL REPORTS
  • 10
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    Human Response to Low-Intensity Sonic Booms Heard Indoors and Outdoors (2010)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Test subjects seated inside and outside a house were exposed to low-intensity N-wave sonic booms during a 3-week test period in June 2006- The house was instrumented to measure the booms both inside and out. F-18 aircraft were flown to achieve a variety of boom overpressures from approximately .1 to .6 psf During four test days, seventy-seven test subjects heard the booms while seated inside and outside the house. Using the Magnitude Estimation methodology and artificial reference sounds ; the subjects rated the annoyance of the booms. Since the same subjects heard similar booms both inside and outside the house, comparative ratings of indoor and outdoor annoyance were obtained. For a given metric level, indoor subjects gave higher annoyance scores than outdoor subjects. For a given boom; annoyance scores inside were on average the same as those outside. In a post-test questionnaire, the majority of subjects rated the indoor booms as more annoying than the outdoor ones. These results are discussed in this paper.
    Keywords: Acoustics
    Type: NASA/TM-2010-216685 , L-19846 , NF1676L-10465
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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