Conceptual and Preliminary Design of a Long Endurance Electric UAV Luís Miguel Almodôvar Parada Thesis to obtain the Master of Science Degree in Aerospace Engineering Supervisor: Prof. André Calado Marta Examination Committee Chairperson: Prof. Filipe Szolnoky Ramos Pinto Cunha Supervisor: Prof. André Calado Marta Member of the Committee: Dr. José Lobo do Vale November 2016 ii Pelaminhafam´ılia,porterpermanecido. iii iv Acknowledgments Firstofall, Iwouldliketoexpress mygratitudetomy thesissupervisor, professorAndre´ Calado Marta, for all technical guidance, patience and moral support throughout the period of time it took me to write thisdocument. Moving on to the extracurricular plan, a word of appreciation is due to the Autonomous Section of AppliedAeronautics(S3A).Itwasthankstotheworkdevelopedatthishands-onorganizationofstudents thatIstartedgaininginterestinmodelaircraft,whichmademelookatthisthesissubjecttwice. Furthermore,Iwanttothankafewfriendsandacquaintancesthathelpedmethroughmyacademic life. Borrowedclassnotes,carrides,sleeplessnightsworkingforcourseprojects,miraculouspiecesof code,etc... allgenuinecontributionsmattered. Finally, I must dedicate this work to my family, the foundation that allowed me to harvest a higher education level. To my parents, for supporting me financially and emotionally, while respecting my decisionsanddailystruggles. Tomygrandparents,fordiligentlynurturingmeovertheyearswithallthe resiliencetheycouldpossiblyseed. Andlastbutnotleast, tomybrotherandtomysister, forbeingthe bestdistractionsofmylife. v vi Resumo A presente tese documenta o projeto conceptual e preliminar de um ve´ıculo ae´reo na˜o tripulado de grandeautonomiamovidoaenergiasolar. Tendoemcontapropo´sitosdevigilaˆncia, operfildamissa˜o requerumasubidainicial,aumataxaquepermitaascender1000msobrepistaem10minutos,seguido de voo nivelado com uma autonomia de 8 horas e um alcance de 200 km durante o equino´cio. Na fase conceptual, va´rias configurac¸o˜es de aeronaves foram avaliadas considerando os requerimentos da missa˜o. Recorrendo a` metodologia de um processo anal´ıtico hiera´rquico, o conceito de avia˜o com caudaemVemotormontadonatraseiradafuselagemfoiescolhidoatrave´sdecomparac¸o˜esemparel- hadasentreos10crite´riosdamissa˜o(Aerodinaˆmica,EstruturasePeso,Integrac¸a˜odePaine´isSolares, Propulsa˜o,FabricoeManutenc¸a˜o,EstabilidadeeControlo,VolumedeCarga,Integrac¸a˜odeVisa˜oRe- motana1a Pessoa,DescolagemeAterragem,eCaracter´ısticasPorta´teis)e8poss´ıveisconfigurac¸o˜es. UmapesquisanomercadodosUAVproporcionouumaestimativainicialparaopesovazioedimenso˜es da aeronave. Atrave´s de uma pesquisa bibliogra´fica, o sistema de comunicac¸o˜es ficou definido de antema˜o e o sistema propulsivo tambe´m foi alvo de uma estimativa inicial. Durante o projeto prelimi- nar, a aeronave foi redimensionada realizando um conjunto de iterac¸o˜es de ponto fixo, cujo ponto de projeto resultante garante que e´ fisicamente poss´ıvel cumprir os requisitos do voo. Aliando mu´ltiplas ana´lises aerodinaˆmicas, realizadas numa ferramenta computacional que suporta baixos nu´meros de Reynolds, com a eficieˆncia apurada para o sistema de propulsa˜o, os consumos de poteˆncia de cada fase da missa˜o foram determinados assumindo condic¸o˜es meteorolo´gicas ideais. A energia solar re- cebidapelospaine´isfotovoltaicosinstaladosfoideterminadaparaumau´nicalocalizac¸a˜o,aplicandoum modelo teo´rico de irradiac¸a˜o em diferentes estac¸o˜es do ano. Verificou-se que no equino´cio de Marc¸o aautonomiaalcanc¸ouas7.5horas,enquantoquenodeSetembrooseuvalorma´ximoaumentoupara quase 10 horas. Um conjunto das partes da aeronave foi desenhado em CAD sem detalhar soluc¸o˜es estruturais para o seu interior. As partes desenvolvidas incluem uma asa de treˆs pec¸as com 5 metros de envergadura, uma fuselagem composta por duas pec¸as desmonta´veis, perfazendo 1.9 metros de comprimento,eduasmetadesindividuaisdeumacaudaemV.Oscomponentesavio´nicosedosistema depropulsa˜otambe´mforammodeladosdeformasimplificadanointeriordaaeronave,comoso´lidosde densidade uniforme. Uma ana´lise de estabilidade de voo foi levada a cabo, resultando numa margem esta´ticade5.6%comC nuloemcondic¸o˜esdevoonivelado. Visionandoumfuturoprojetodetalhado, m oenvelopedevoocruzeirofoigeradoeadistribuic¸a˜odepressa˜onaasafoiobtida. Palavras-chave: UAVSolar,ProcessoAnal´ıticoHiera´rquico,PontodeProjeto,BaixoNu´mero deReynolds,Autonomia,EnvelopedeVoo. vii viii Abstract The present thesis documents the conceptual and preliminary design of a solar long endurance Un- manned Aerial Vehicle (UAV). Having in mind surveillance goals, the mission profile requires an initial climb, at a rate that allows to ascend 1000 m above runway in 10 minutes, followed by cruise with an enduranceof8 hoursanda range200kmduring theequinox. Intheconceptualstage, several aircraft configurationswereevaluatedconsideringthemissionrequirements. ResortingtotheAnalyticHierarchy Processmethodology,therearpusherV-tailairplaneconceptwaschosenthroughpairwisecomparisons between10missioncriteria(Aerodynamics,StructuresanWeight,SolarPanelsIntegration,Propulsion, Manufacturing and Maintenance, Stability and Control, Payload Volume, Remote-Person View Integra- tion,Take-offandLandingandPortableCapabilities)and8prospectivecandidateconfigurations. AUAV market investigation provided an initial estimate of the empty weight fraction and airframe dimensions. Throughbibliographicresearch,thecommunicationssystemwasdefinedbeforehandandthepropulsion system also received an initial estimate. In the preliminary design phase, the airframe was resized by performing a set of fixed point iterations, whose resulting design point ensured it is physically possible to fulfill flight requirements. Allying multiple aerodynamic analyses, performed on a low Reynolds num- ber computational tool, with the ascertained efficiency of the propulsion system, power consumption at each mission stage was determined under ideal weather conditions. The solar energy received by the photo-voltaic arrays installed was determined in a single location applying a theoretical irradiation modelindifferentseasonsoftheyear. ItwasverifiedthatintheMarchequinoxendurancereached7.5 hours, while in September its maximum increased to almost 10 hours. An aircraft CAD assembly was modeledwithoutinternalairframedetail. Thedevelopedpartsincludeathree-piece5meterspanwing, a fuselage composed by two connectable pieces, totaling 1.9 meter length, and two individual V-tail halves. On-boardpropulsionandavionicscomponentswerealsomodeledinasimplifiedway,assolids ofuniformdensity. Aflightstabilityanalysiswasperformed,resultinginastaticmarginof5.6%withnull C incruiseconditions. Lookingatafuturedetaileddesign,thecruiseflightenvelopewascreatedand m thewingpressuredistributionwasobtained. Keywords: Solar UAV, Analytic Hierarchy Process, Design Point, Low Reynolds Number, En- durance,FlightEnvelope. ix x
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