NASA/TP-1999-209012FlushAirdataSensing(FADS)SystemCalibrationProceduresandResultsforBluntForebodiesBrentR.Cobleigh,StephenA.Whitmore,andEdwardA.Haering,Jr.DrydenFlightResearchCenterEdwards,CaliforniaJerryBorrerJohnsonSpaceCenterHouston,TexasV.EricRobackLangleyResearchCenterHampton,VirginiaNovember1999TheNASASTIProgramOffice...inProfileSinceitsfounding,NASAhasbeendedicatedtotheadvancementofaeronauticsandspacescience.TheNASAScientificandTechnicalInformation(STI)ProgramOfficeplaysakeypartinhelpingNASAmaintainthisimportantrole.TheNASASTIProgramOfficeisoperatedbyLangleyResearchCenter,theleadcenterforNASA’sscientificandtechnicalinformation.TheNASASTIProgramOfficeprovidesaccesstotheNASASTIDatabase,thelargestcollectionofaeronauticalandspacescienceSTIintheworld.TheProgramOfficeisalsoNASA’sinstitutionalmechanismfordisseminatingtheresultsofitsresearchanddevelopmentactivities.TheseresultsarepublishedbyNASAintheNASASTIReportSeries,whichincludesthefollowingreporttypes:•TECHNICALPUBLICATION.ReportsofcompletedresearchoramajorsignificantphaseofresearchthatpresenttheresultsofNASAprogramsandincludeextensivedataortheoreticalanalysis.Includescompilationsofsignificantscientificandtechnicaldataandinformationdeemedtobeofcontinuingreferencevalue.NASA’scounterpartofpeer-reviewedformalprofessionalpapersbuthaslessstringentlimitationsonmanuscriptlengthandextentofgraphicpresentations.•TECHNICALMEMORANDUM.Scientificandtechnicalfindingsthatarepreliminaryorofspecializedinterest,e.g.,quickreleasereports,workingpapers,andbibliographiesthatcontainminimalannotation.Doesnotcontainextensiveanalysis.•CONTRACTORREPORT.ScientificandtechnicalfindingsbyNASA-sponsoredcontractorsandgrantees.•CONFERENCEPUBLICATION.Collectedpapersfromscientificandtechnicalconferences,symposia,seminars,orothermeetingssponsoredorcosponsoredbyNASA.•SPECIALPUBLICATION.Scientific,technical,orhistoricalinformationfromNASAprograms,projects,andmission,oftenconcernedwithsubjectshavingsubstantialpublicinterest.•TECHNICALTRANSLATION.English-languagetranslationsofforeignscientificandtechnicalmaterialpertinenttoNASA’smission.SpecializedservicesthatcomplementtheSTIProgramOffice’sdiverseofferingsincludecreatingcustomthesauri,buildingcustomizeddatabases,organizingandpublishingresearchresults...evenprovidingvideos.FormoreinformationabouttheNASASTIProgramOffice,seethefollowing:•AccesstheNASASTIProgramHomePageat•E-mailyourquestionviatheInternettohelp@sti.nasa.gov•FaxyourquestiontotheNASAAccessHelpDeskat(301)621-0134•TelephonetheNASAAccessHelpDeskat(301)621-0390•Writeto:NASAAccessHelpDeskNASACenterforAeroSpaceInformation7121StandardDriveHanover,MD21076-1320NASA/TP-1999-209012FlushAirdataSensing(FADS)SystemCalibrationProceduresandResultsforBluntForebodiesBrentR.Cobleigh,StephenA.Whitmore,andEdwardA.Haering,Jr.DrydenFlightResearchCenterEdwards,CaliforniaJerryBorrerJohnsonSpaceCenterHouston,TexasV.EricRobackLangleyResearchCenterHampton,VirginiaNovember1999NationalAeronauticsandSpaceAdministrationDrydenFlightResearchCenterEdwards,California93523-0273NOTICEUseoftradenamesornamesofmanufacturersinthisdocumentdoesnotconstituteanofficialendorsementofsuchproductsormanufacturers,eitherexpressedorimplied,bytheNationalAeronauticsandSpaceAdministration.Availablefromthefollowing:NASACenterforAeroSpaceInformation(CASI)NationalTechnicalInformationService(NTIS)7121StandardDrive5285PortRoyalRoadHanover,MD21076-1320Springfield,VA22161-2171(301)621-0390(703)487-4650ACKNOWLEDGMENTCoverphotocourtesyofNASALangleyResearchCenter,L97-1039,“X-33MetalModelTestinginLowTurbulencePressureTunnel.”1AmericanInstituteofAeronauticsandAstronauticsFLUSHAIRDATASENSING(FADS)SYSTEMCALIBRATIONPROCEDURESANDRESULTSFORBLUNTFOREBODIES*BrentR.Cobleigh,†StephenA.Whitmore,‡andEdwardA.Haering,Jr.§NASADrydenFlightResearchCenterEdwards,CaliforniaJerryBorrer¶NASAJohnsonSpaceCenterHouston,TexasV.EricRoback#NASALangleyResearchCenterHampton,VirginiaAbstractBlunt-forebodypressuredataareusedtostudythebehavioroftheNASADrydenFlightResearchCenterflushairdatasensing(FADS)pressuremodelandsolutionalgorithm.Themodelrelatessurfacepressuremeasurementstotheairdatastate.SplicedfromthepotentialflowsolutionforuniformflowoverasphereandthemodifiedNewtonianimpacttheory,themodelisshowntoapplytoawiderangeofblunt-forebodyshapesandMachnumbers.Calibrationsofasphere,sphericalcones,aRankinehalf-body,andtheF-14,F/A-18,X-33,X-34,andX-38configurationsareshown.Thethreecalibrationparametersarewell-behavedfromMach0.25toMach5.0,anangle-of-attackrangeextendingtogreaterthan30°,andanangle-of-sidesliprangeextendingtogreaterthan15°.Contrarytothesharpcalibrationchangesfoundontraditionalpitot-staticsystemsattransonicspeeds,theFADScalibrationsaresmooth,monotonicfunctionsofMachnumberandeffectiveanglesofattackandsideslip.BecausetheFADScalibrationissensitivetopressureportlocation,detailedmeasurementsoftheactualpressureport*Patentpending.†AerospaceEngineer,Seniormember,AIAA.‡AerospaceEngineer,Seniormember,AIAA.§AerospaceEngineer.¶SeniorSystemsEngineer.#AerospaceTechnologist,Seniormember,AI