Wind Tunnel Evaluation of a Model Helicopter Main-

NASA/TP-2001-211260AMCOM/AFDD/TR-00-A-003ARL-TR-2154WindTunnelEvaluationofaModelHelicopterMain-RotorBladeWithSlottedAirfoilsattheTipKevinW.NoonanJointResearchProgramOfficeAeroflightdynamicsDirectorateU.S.ArmyAviationandMissileCommandLangleyResearchCenter,Hampton,VirginiaWilliamT.Yeager,Jr.,JeffreyD.Singleton,MatthewL.Wilbur,andPaulH.MirickVehicleTechnologyCenterU.S.ArmyResearchLaboratoryLangleyResearchCenter,Hampton,VirginiaDecember2001TheNASASTIProgramOffice...inProfileSinceitsfounding,NASAhasbeendedicatedtotheadvancementofaeronauticsandspacescience.TheNASAScientificandTechnicalInformation(STI)ProgramOfficeplaysakeypartinhelpingNASAmaintainthisimportantrole.TheNASASTIProgramOfficeisoperatedbyLangleyResearchCenter,theleadcenterforNASA’sscientificandtechnicalinformation.TheNASASTIProgramOfficeprovidesaccesstotheNASASTIDatabase,thelargestcollectionofaeronauticalandspacescienceSTIintheworld.TheProgramOfficeisalsoNASA’sinstitutionalmechanismfordisseminatingtheresultsofitsresearchanddevelopmentactivities.TheseresultsarepublishedbyNASAintheNASASTIReportSeries,whichincludesthefollowingreporttypes:•TECHNICALPUBLICATION.ReportsofcompletedresearchoramajorsignificantphaseofresearchthatpresenttheresultsofNASAprogramsandincludeextensivedataortheoreticalanalysis.Includescompilationsofsignificantscientificandtechnicaldataandinformationdeemedtobeofcontinuingreferencevalue.NASAcounterpartofpeer-reviewedformalprofessionalpapers,buthavinglessstringentlimitationsonmanuscriptlengthandextentofgraphicpresentations.•TECHNICALMEMORANDUM.Scientificandtechnicalfindingsthatarepreliminaryorofspecializedinterest,e.g.,quickreleasereports,workingpapers,andbibliographiesthatcontainminimalannotation.Doesnotcontainextensiveanalysis.•CONTRACTORREPORT.ScientificandtechnicalfindingsbyNASA-sponsoredcontractorsandgrantees.•CONFERENCEPUBLICATION.Collectedpapersfromscientificandtechnicalconferences,symposia,seminars,orothermeetingssponsoredorco-sponsoredbyNASA.•SPECIALPUBLICATION.Scientific,technical,orhistoricalinformationfromNASAprograms,projects,andmissions,oftenconcernedwithsubjectshavingsubstantialpublicinterest.•TECHNICALTRANSLATION.English-languagetranslationsofforeignscientificandtechnicalmaterialpertinenttoNASA’smission.SpecializedservicesthatcomplementtheSTIProgramOffice’sdiverseofferingsincludecreatingcustomthesauri,buildingcustomizeddatabases,organizingandpublishingresearchresults...evenprovidingvideos.FormoreinformationabouttheNASASTIProgramOffice,seethefollowing:•AccesstheNASASTIProgramHomePageat•[e-mail]•FaxyourquestiontotheNASASTIHelpDeskat(301)621-0134•TelephonetheNASASTIHelpDeskat(301)621-0390•Writeto:NASASTIHelpDeskNASACenterforAeroSpaceInformation7121StandardDriveHanover,MD21076-1320NationalAeronauticsandSpaceAdministrationLangleyResearchCenterHampton,Virginia23681-2199NASA/TP-2001-211260AMCOM/AFDD/TR-00-A-003ARL-TR-2154WindTunnelEvaluationofaModelHelicopterMain-RotorBladeWithSlottedAirfoilsattheTipKevinW.NoonanJointResearchProgramOfficeAeroflightdynamicsDirectorateU.S.ArmyAviationandMissileCommandLangleyResearchCenter,Hampton,VirginiaWilliamT.Yeager,Jr.,JeffreyD.Singleton,MatthewL.Wilbur,andPaulH.MirickVehicleTechnologyCenterU.S.ArmyResearchLaboratoryLangleyResearchCenter,Hampton,VirginiaDecember2001Availablefrom:NASACenterforAeroSpaceInformation(CASI)NationalTechnicalInformationService(NTIS)7121StandardDrive5285PortRoyalRoadHanover,MD21076-1320Springfield,VA22161-2171(301)621-0390(703)605-6000Theuseoftrademarksornamesofmanufacturersinthisreportisforaccuratereportinganddoesnotconstituteanofficialendorsement,eitherexpressedorimplied,ofsuchproductsormanufacturersbytheNationalAeronauticsandSpaceAdministrationortheU.S.Army.SummaryDataforrotorsusingunconventionalairfoilsareofinteresttopermitanevaluationofthistechnology’scapabilitytomeettheU.S.Army’sneedforincreasedhelicoptermissioneffectivenessandimprovedsafetyandsurvivability.Thus,anexperimentalinvestigationwasconductedintheLangleyTransonicDynamicsTunnel(TDT)toevaluatetheeffectofusingslottedairfoilsintherotorbladetipregion(85to100percentradius)onrotoraerodynamicperformanceandloads.Fourrotorconfigurationsweretestedinforwardflightatadvanceratiosfrom0.15to0.45andinhoverin-groundeffect.ThehovertipMachnumberwas0.627,whichisrepresentativeofadesignpointof4000-ftgeometricaltitudeandatemperatureof95°F.Thebaselinerotorconfigurationhadaconventionalsingle-elementairfoilinthetipregion.Asecondrotorcon-figurationhadaforward-slottedairfoilwitha-6°slat,athirdconfigurationhadaforward-slottedairfoilwitha-10°slat,andafourthconfigurationhadanaft-slot-tedairfoilwitha3°flap(trailingedgedown).Theresultsofthisinvestigationindicatethatthe-6°slatconfigurationofferssomeperformanceandloadsbenefitsovertheotherthreeconfigurations.Atthehigherrotorliftcoefficientsateachadvanceratio,the-6°slatconfigurationhadthelowestrotortorquecoefficient,whereasthebaselinerotorhadthelowesttorquecoefficientforthelowerliftcoefficients.Forhoverin-groundeffect,the-6°sla