Fundamentals of Aerospace Engineering PDF 2014

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Anundergr aduateint roduct orycourset o t hefas cinati ngdisci pli neofaerospace Fundamentalsof ng neeri engi neeri ng Fundamentalsof Aeros paceEngineeri ng paceEngi ManuelSol erisas sist antPr ofessoratthe Ani ntr oduct orycour set oaer onaut icalengi neer ing Uni versi dadCar losIIIdeMadr i d.He teachesunder graduateandgr aduat e Aeros cour sesinthef ieldofaer ospace engi neeri ng.Hi sr esearchinterestsfocus onopt i malcont rol ,aviati onenvi r onmental f inger pri nt,andai rnavigation.In201 3hewasawar ded wit htheSESAR youngs cientistaward. Fundament alsofAer ospaceEngi neeringi sat extbook thatpr ovidesani nt roductor y,thoroughover view of aeronaut icalengi neer ing,andi tisaimedats ervingas reference f oran under gr aduat e cour se on aer ospace engi neer ing.Thebooki sdividedi ntothr eepar ts, namel y:I ntroduct ion( TheScope,Gener ali ties),The Aircr aft(Aer odynami cs,Mat ericalsandSt r uctur es, Propul si on,I nstrument sandSys t ems ,Flight Mechani cs ) ,andAi rTr anspor t at i on,Ai r por ts,andAi r ManuelSoler Navi gat ion.Thi sbooki sli cencedunder CC- BY- NC- SA.Theel ectr oni cver si oni savai l abl ein openacces satwww. aerospaceengi neering.es. Ma nue lSol er Fundamentals of Aerospace Engineering An introductory course to aeronautical engineering Fundamentals of Aerospace Engineering An introductory course to aeronautical engineering Manuel Soler. Assistant Professor, Universidad Carlos III. Manuel Soler [Ed.]. Printed by Create Space. Madrid, January 2014. All contents of this books are subject to the following license except when explicitly speciﬁed the opposite. C BY: $ \ This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. You are free to copy, distribute, and publicly communicate this creation as long as*: BY: You give credit to the author and editor in the terms herein speciﬁed. $ You do not use it for commercial purposes. \ You license your derivative creations under the identical terms. C * Some of these conditions might not apply if you obtain explicit authorization by the owner of the rights. Notice also that this license applies to all contents except when explicitly licensed under other licenses as it is the case for those passages based on Wikipedia sources (licensed under CC-BY-SA) and some ﬁgures. Interior design and layout by Manuel Fernando Soler Arnedo using LATEX and font iwona. Cover design by Francisco Javier García Caro and Manuel Fernando Soler Arnedo, First edition January, 2014 © Manuel Fernando Soler Arnedo, 2014 © Manuel Soler [Ed.] 2014 isbn-13: 978-14-937277-5-9 isbn-10: 1493727753 Printed by Create Space Dedicado a Reme, con amor virtuoso. Education is not the piling on of learning, information, data, facts, skills, or abilities–that’s training or instruction–but is rather a making visible what is hidden as a seed [...] To be educated, a person doesn’t have to know much or be informed, but he or she does have to have been exposed vulnerably to the transformative events of an engaged human life [...] One of the greatest problems of our time is that many are schooled but few are educated. Thomas More, The Education of the Heart. Lo que más necesitan, aun los mejores de nuestros buenos estudiantes, es mayor intensidad de vida, mayor actividad para todo, en espíritu y cuerpo: trabajar más, sentir más, pensar más, querer más, jugar más, dormir más, comer más, lavarse más, divertirse más. Francisco Giner de los Ríos. El espíritu de la casa, como llamaban los residentes al esfuerzo para transmitir la mejor tradición española de educación liberal, quedaba reﬂejado en una cierta forma de vida construida en torno a la responsabilidad personal, el trabajo, la búsqueda de la excelencia, el culto a la amistad y el ocio creativo, con el ﬁn de que el esfuerzo particular se viera proyectado en la sociedad [...] El espíritu de la casa simboliza su modelo de educación integral, basado en la tolerancia, el pluralismo y el diálogo entre distintas disciplinas de las artes y las ciencias, entre diferentes generaciones, y entre tradición y modernidad [...] Nota sobe El Espíritu de la casa. Exposición 100 años de la residencia de estudiantes. Residencia de estudiantes, Madrid. Una niña apunto de cumplir 10 años declara: cuando sea mayor, me inscribiré en el partido más cruel. Si mi partido está en el poder, no tendré nada que temer; y si es el otro sufriré menos puesto que es el partido menos cruel el que me perseguirá [...] Conozco ese razonamiento [...] Albert Camus, Carnets, Vol. 3. Este es el verdadero problema: suceda lo que suceda, yo siempre te defenderé contra el pelotón de fusilamiento, pero tú te verás obligado a aprobar que me fusilen. Episodio vital de Albert Camus: palabras a un antiguo resistente, recién afiliado al partido comunista. Valía más perecer con la justicia que triunfar con la injusticia. Albert Camus, en algún momento de la postguerra. La libertad no es un estado natural del hombre, es una conquista perpetua frente a la naturaleza, la sociedad y uno mismo. Albert Camus en el semanario L’Express, 1955. Albert Camus, Notas sacadas de Revista Turia, num. 107. About the author Manuel Soler received a Bachelor’s Degree in Aeronautical and Aerospace Engineering (5-Year B.Sc, 07), a Master’s degree in Aerospace Science and Technology (M.Sc, 11), both from the Universidad Politécnica de Madrid, and a Doctorate Degree in Aerospace Engineering (Ph.D, 13) from the Universidad Rey Juan Carlos, Madrid. He developed his early professional career in companies of the aeronautical sector. In 2008, he joined the Universidad Rey Juan Carlos, where he was a lecturer in the area of aerospace engineering. Since January 2014, Manuel Soler is Assistant Professor at the Universidad Carlos III de Madrid, where he teaches undergraduate and graduate courses in the ﬁeld of aerospace engineering and conducts research activities. He has been a visiting scholar at ETH Zurich, Switzerland, and UC Berkeley, USA. His research interests focus on optimal control with application to green trajectory planning for commercial aircraft in Air Traﬃc Management (ATM). Dr. Soler has participated in several research projects and has published his work in diﬀerent international journal and conference papers. He has been awarded with the SESAR young scientist award 2013. Contents Contents Preface........................................ xvii Acknowledgments................................... xviii List of ﬁgures..................................... xxiii List of tables..................................... xxvi I Introduction 1 1 The Scope 3 1.1 Engineering.................................. 4 1.2 Aerospace activity............................... 5 1.3 Aviation research agenda........................... 12 1.3.1 Challenges.............................. 12 1.3.2 Clean Sky.............................. 13 1.3.3 SESAR................................ 15 References...................................... 17 2 Generalities 19 2.1 Classiﬁcation of aerospace vehicles..................... 20 2.1.1 Fixed wing aircraft.......................... 21 2.1.2 Rotorcraft............................... 23 2.1.3 Missiles................................ 24 2.1.4 Space vehicles............................ 25 2.2 Parts of the aircraft.............................. 27 2.2.1 Fuselage............................... 27 2.2.2 Wing................................. 28 2.2.3 Empennage.............................. 30 2.2.4 Main control surfaces........................ 31 2.2.5 Propulsion plant........................... 32 ix Contents 2.3 Standard atmosphere............................. 33 2.3.1 Hypotheses.............................. 33 2.3.2 Fluid-static equation......................... 34 2.3.3 ISA equations............................ 34 2.3.4 Warm and cold atmospheres.................... 36 2.3.5 Barometric altitude.......................... 37 2.4 System references............................... 37 2.5 Problems.................................... 39 References...................................... 43 II The aircraft 45 3 Aerodynamics 47 3.1 Fundamentals of ﬂuid mechanics....................... 48 3.1.1 Generalities............................. 48 3.1.2 Continuity equation......................... 49 3.1.3 Quantity of movement equation................... 50 3.1.4 Viscosity............................... 52 3.1.5 Speed of sound............................ 56 3.2 Airfoils shapes................................. 58 3.2.1 Airfoil nomenclature......................... 59 3.2.2 Generation of aerodynamic forces.................. 60 3.2.3 Aerodynamic dimensionless coeﬃcients.............. 63 3.2.4 Compressibility and drag-divergence Mach number........ 66 3.3 Wing aerodynamics.............................. 68 3.3.1 Geometry and nomenclature..................... 68 3.3.2 Flow over a ﬁnite wing....................... 69 3.3.3 Lift and induced drag in wings................... 71 3.3.4 Characteristic curves in wings.................... 72 3.3.5 Aerodynamics of wings in compressible and supersonic regimes. 73 3.4 High-lift devices................................ 74 3.4.1 Necessity of high-lift devices.................... 74 3.4.2 Types of high-lift devices...................... 75 3.4.3 Increase in CLmax........................... 77 3.5 Problems.................................... 79 References...................................... 101 4 Aircraft structures 103 4.1 Generalities.................................. 104 4.2 Materials.................................... 108 x Contents 4.2.1 Properties.............................. 108 4.2.2 Materials in aircraft......................... 109 4.3 Loads...................................... 113 4.3.1 Fuselage loads............................ 113 4.3.2 Wing and tail loads......................... 114 4.3.3 Landing gear loads......................... 114 4.3.4 Other loads.............................. 114 4.4 Structural components of an aircraft..................... 114 4.4.1 Structural elements and functions of the fuselage......... 115 4.4.2 Structural elements and functions of the wing........... 117 4.4.3 Tail.................................. 118 4.4.4 Landing gear............................. 118 References...................................... 119 5 Aircraft instruments and systems 121 5.1 Aircraft instruments.............................. 122 5.1.1 Sources of data........................... 123 5.1.2 Instruments requirements...................... 126 5.1.3 Instruments to be installed in an aircraft.............. 126 5.1.4 Instruments layout.......................... 130 5.1.5 Aircrafts’ cockpits.......................... 131 5.2 Aircraft systems................................ 135 5.2.1 Electrical system........................... 135 5.2.2 Fuel system............................. 137 5.2.3 Hydraulic system........................... 139 5.2.4 Flight control systems: Fly-By-Wire................ 140 5.2.5 Air conditioning & pressurisation system.............. 142 5.2.6 Other systems............................ 143 References...................................... 145 6 Aircraft propulsion 147 6.1 The propeller................................. 148 6.1.1 Propeller propulsion equations................... 148 6.2 The jet engine................................. 150 6.2.1 Some aspects about thermodynamics................ 151 6.2.2 Inlet.................................. 153 6.2.3 Compressor.............................. 154 6.2.4 Combustion chamber......................... 156 6.2.5 Turbine................................ 158 6.2.6 Nozzles................................ 160 6.3 Types of jet engines.............................. 162 xi Contents 6.3.1 Turbojets............................... 162 6.3.2 Turbofans............................... 164 6.3.3 Turboprops.............................. 165 6.3.4 After-burning turbojet........................ 166 References...................................... 167 7 Mechanics of flight 169 7.1 Performances.................................. 170 7.1.1 Reference frames........................... 170 7.1.2 Hypotheses.............................. 170 7.1.3 Aircraft equations of motion..................... 172 7.1.4 Performances in a steady linear ﬂight............... 175 7.1.5 Performances in steady ascent and descent ﬂight......... 175 7.1.6 Performances in gliding....................... 176 7.1.7 Performances in turn maneuvers.................. 177 7.1.8 Performances in the runway..................... 179 7.1.9 Range and endurance........................ 182 7.1.10 Payload-range diagram....................... 184 7.2 Stability and control............................. 187 7.2.1 Fundamentals of stability...................... 187 7.2.2 Fundamentals of control....................... 189 7.2.3 Longitudinal balancing........................ 191 7.2.4 Longitudinal stability and control.................. 192 7.2.5 Lateral-directional stability and control.............. 194 7.3 Problems.................................... 196 References...................................... 229 III Air Transportation, Airports, and Air Navigation 231 8 Air transportation 233 8.1 Regulatory framework............................. 234 8.1.1 ICAO................................. 234 8.1.2 IATA.................................. 239 8.2 The market of aircraft for commercial air transportation.......... 240 8.2.1 Manufacturers in the current market of aircraft.......... 241 8.2.2 Types of aircraft........................... 243 8.2.3 Future market of aircraft....................... 245 8.3 Airlines’ cost strucutre............................ 247 8.3.1 Operational costs.......................... 248 8.4 Environmental impact............................. 256 xii Contents 8.4.1 Sources of environmental impact.................. 256 8.4.2 Aircraft operations’ environmental ﬁngerprint............ 257 References...................................... 268 9 Airports 269 9.1 Introduction.................................. 270 9.1.1 Airport designation and naming................... 270 9.1.2 The demand of air transportation.................. 271 9.1.3 The master plan........................... 273 9.2 Airport conﬁguration.............................. 273 9.2.1 Airport description.......................... 273 9.2.2 The runway.............................. 276 9.2.3 The terminal............................. 282 9.2.4 Airport services............................ 287 9.3 Airport operations............................... 288 9.3.1 Air Traﬃc Management (ATM) services.............. 288 9.3.2 Airport navigational aids...................... 289 9.3.3 Safety management......................... 295 9.3.4 Environmental concerns....................... 295 References...................................... 297 10 Air navigation 299 10.1 Introduction.................................. 300 10.1.1 Deﬁnition............................... 300 10.1.2 History................................ 300 10.2 Technical and operative framework...................... 306 10.2.1 Communications, Navigation & Surveillance (CNS)........ 306 10.2.2 Air Traﬃc Management (ATM)................... 308 10.3 Airspace Management (ASM)........................ 311 10.3.1 ATS routes.............................. 311 10.3.2 Airspace organization in regions and control centers....... 314 10.3.3 Restrictions in the airspace..................... 316 10.3.4 Classiﬁcation of the airspace according to ICAO......... 317 10.3.5 Navigation charts.......................... 317 10.3.6 Flight plan.............................. 321 10.4 Technical support: CNS system....................... 321 10.4.1 Communication systems....................... 322 10.4.2 Navigation systems......................... 325 10.4.3 Surveillance systems......................... 343 10.5 SESAR concept................................ 348 10.5.1 Single European Sky........................ 348 xiii Contents 10.5.2 SESAR................................ 348 References...................................... 349 IV Appendixes 351 A 6-DOF Equations of Motion 353 A.1 Reference frames............................... 354 A.2 Orientation between reference frames.................... 355 A.2.1 Wind axes-Local horizon orientation................ 357 A.2.2 Body axed-Wind axes orientation.................. 358 A.3 General equations of motion......................... 358 A.3.1 Dynamic relations.......................... 358 A.3.2 Forces acting on an aircraft..................... 360 A.4 Point mass model............................... 361 A.4.1 Dynamic relations.......................... 361 A.4.2 Mass relations............................ 362 A.4.3 Kinematic relations......................... 362 A.4.4 Angular kinematic relations..................... 364 A.4.5 General diﬀerential equations system............... 364 References...................................... 367 Index 374 xiv Preface Preface Fundamentals of Aerospace Engineering covers an undergraduate, introductory course to aeronautical engineering and aims at combining theory and practice to provide a comprehensive, thorough introduction to the fascinating, yet complex discipline of aerospace engineering. This book is the ulterior result of three year of teaching a course called Aerospace Engineering in the ﬁrst year of a degree in aerospace engineering (with a minor in air navigation) at the Universidad Rey Juan Carlos, in Madrid, Spain. When I started preparing the course, back in 2010, I realized there was not a suitable text-book reference due to two fundamental reasons: First, the above mentioned degree was in english, a trend that is becoming more and more popular in Spain now, but it was completely new at those days. Therefore, the classical references used in similar courses in Spain (introductory courses in aeronautical and aerospace engineering) were written in Spanish. Second, as opposed to most parts of the world, e.g., the USA and most of Europe, where traditionally airports, air transportation, and air navigation are included in the branch of civil or transportation engineering, the studies of aeronautical and aerospace engineering in Spain (due to national legislation) include aspects related to airports, air transportation, and air navigation. As a consequence, the classical references written in english and used as classical references in similar courses did not cover part of the contents of the course. Therefore, I started writing my own lecture notes: in english and covering issues related to airports, air transportation, and air navigation. After three preliminary, draft versions used as reference lecture notes throughout the past years, they have evolved into the book I’m presenting herein. The book is divided into three parts, namely: Introduction, The Aircraft, and Air Transportation, Airports, and Air Navigation. The ﬁrst part is divided in two chapters in which the student must achieve to understand the basic elements of atmospheric ﬂight (ISA and planetary references) and the technology that apply to the aerospace sector, in particular with a speciﬁc comprehension of the elements of an aircraft. The second part focuses on the aircraft and it is divided in ﬁve chapters that introduce the student to aircraft aerodynamics (ﬂuid mechanics, airfoils, xv Preface wings, high-lift devices), aircraft materials and structures, aircraft propulsion, aircraft instruments and systems, and atmospheric ﬂight mechanics (performances and stability and control). The third part is devoted to understand the global air transport system (covering both regulatory and economical frameworks), the airports, and the global air navigation system (its history, current status, and future development). The theoretical contents are illustrated with ﬁgures and complemented with some problems/exercises. The problems deal, fundamentally, with aerodynamics and ﬂight mechanics, and were proposed in diﬀerent exams. The course is complemented by a practical approach. Students should be able to apply theoretical knowledge to solve practical cases using academic (but also industrial) software, such as MATLAB (now we are moving towards open source software such as SciLab). The course also includes a series of assignments to be completed individually or in groups. These tasks comprise an oral presentation, technical reports, scientiﬁc papers, problems, etc. The course is supplemented by scientiﬁc and industrial seminars, recommended readings, and a visit to an institution or industry related to the study and of interest to the students. All this documentation is not explicitly in the book but can be accessed online at the book’s website www.aerospaceengineering.es. The slides of the course are also available at the book’s website www.aerospaceengineering.es. At this point, the reader should have noticed that space engineering is almost totally missing. I’m afraid this is true. The course originally was aimed at providing an introduction to aeronautical engineering with the focus on commercial aircraft, and thus space vehicles, space systems, space materials, space operations, and/or orbital mechanics are not covered in this book. Neither helicopters or unmanned air vehicles are covered. This is certainly something to add in future editions. Fundamentals of Aerospace Engineering is licensed under a Creative Commons Attribution-Non Comercial-Share Alike (CC BY-NC-SA) 3.0 License, and it is oﬀered in open access both in "pdf" and "epub" formats. The document can be accessed and downloaded at the book’s website www.aerospaceengineering.es This licensing is aligned with a philosophy of sharing and spreading knowledge. Writing and revising over and over this book has been an exhausting, very time consuming activity. To acknowledge author’s eﬀort, a donation platform has been activated at the book’s website www.aerospaceengineering.es. Also, printed copies can be acquired at low cost price (lower than self printing) via Amazon and/or OMM Campus Libros, which has edited a printed copy of the book at a low price for students. Manuel Soler. xvi Acknowledgments Acknowledgments The list of people that has contributed to this book is immense. Unfortunately, I can not cite all of them herein. First of all, I have to acknowledge the contribution of all the students that I have had the pleasure to teach during these three years. You are the reason of this book. All of them, directly or indirectly, have contributed to the ﬁnal birth of the manuscript. The initial version and all the improved versions (revision after revision on a daily basis) have been encouraged by a motivation inspired in delivering the best material for their formation. They have also pointed out several grammar errors, typographical errors, structural inconsistencies, passages not properly exposed, and so on and so forth. Thank you guys. I have to acknowledge all authors by whom the contents of the book are inspired. Special thanks to all my mentors in the School of Aeronautical Engineering at the Polytechnic University of Madrid: the lecture notes that I used as a student almost 15 years ago have been the primary source of material that I consulted when I ﬁrst started writing this book. Also, special thanks to all contributors to wikipedia and other open source resources: many ﬁgures and some passages have been retrieved from wikipedia; also, some CAD ﬁgures were downloaded from the open source repository BIBCAD. I own special thanks to two colleges, Luis Cadarso and Javier Esquillor, who invested part of their busy time in reviewing some of the chapters of the book, motivated me to continue on, and gave me some valuable advises. For this edition, I have to acknowledge Franscisco Javier García Caro for a preliminary cover design that I used as template for ﬁnal design. Also the team of Desarrollo Creativo for the book’s website design. Last but not least, this book would have been impossible without the patience and support of my beloved partner Reme and my family. xvii List of Figures List of Figures 1.1 Flag companies and low cost companies.................. 8 1.2 International Space Station (ISS)...................... 9 1.3 Contributors to reducing emissions...................... 14 2.1 Classiﬁcation of air vehicles......................... 20 2.2 Aerostats.................................... 21 2.3 Gliders..................................... 21 2.4 Military aircraft types............................. 22 2.5 Civil aircraft types............................... 23 2.6 Helicopter................................... 24 2.7 Space shuttle: Discovery............................ 26 2.8 Parts of an aircraft.............................. 27 2.9 Types of fuselages............................... 28 2.10 Aircraft’s plant-form types........................... 29 2.11 Wing vertical position............................. 29 2.12 Wing and empennage devices........................ 30 2.13 Aircraft’s empennage types.......................... 31 2.14 Actions on the control surfaces........................ 32 2.15 Propulsion plant................................ 33 2.16 Diﬀerential cylinder of air.......................... 35 2.17 ISA atmosphere................................ 36 3.1 Stream line.................................. 49 3.2 Stream tube.................................. 49 3.3 Continuity equation............................... 50 3.4 Quantity of movement............................. 51 3.5 Viscosity.................................... 53 3.6 Airfoil with boundary layer.......................... 54 xix List of Figures 3.7 Boundary layer transition........................... 55 3.8 Eﬀects of the speed of sound in airfoils................... 57 3.9 Aerodynamic forces and moments....................... 58 3.10 Description of an airfoil............................ 59 3.11 Description of an airfoil with angle of attack................ 60 3.12 Pressure and friction stress over an airfoil................. 61 3.13 Aerodynamic forces and moments over an airfoil.............. 61 3.14 Aerodynamic forces and moments over an airfoil with angle of attack... 61 3.15 Lift generation................................. 62 3.16 Aerodynamic forces and torques over an airfoil............... 64 3.17 Lift and drag characteristic curves...................... 66 3.18 Divergence Mach............................... 67 3.19 Supercritical airfoils.............................. 67 3.20 Wing geometry................................ 69 3.21 Coeﬃcient of lift along a wingspan..................... 70 3.22 Whirlwind trail................................ 70 3.23 Eﬀective angle of attack............................ 71 3.24 Induced drag.................................. 71 3.25 Characteristic curves in wings......................... 73 3.26 Types of high-lift devices........................... 76 3.27 Eﬀects of high lift devices in airfoil ﬂow................... 77 3.28 Distribution of the coeﬃcient of pressures (Problem 3.1).......... 80 3.29 Coeﬃcient of lift along the wingspan (Problem 3.1)............. 81 3.30 Characteristic curves of a NACA 4410 airfoil................. 83 3.31 Plant-form of the wing (Problem 3.3).................... 87 3.32 Distribution of the coeﬃcient of pressures (Problem 3.4).......... 93 3.33 Coeﬃcient of lift along the wingspan (Problem 3.4)............. 94 3.34 Plant-form of the wing (Problem 3.5).................... 96 4.1 Normal stress................................. 104 4.2 Bending.................................... 104 4.3 Torsion..................................... 105 4.4 Shear stress due to bending......................... 105 4.5 Shear stress due to torsion.......................... 106 4.6 Stresses in a plate.............................. 106 4.7 Normal deformation.............................. 106 4.8 Tangential deformation............................ 107 4.9 Behavior of an isotropic material....................... 107 4.10 Fibre-reinforced composite materials..................... 111 4.11 Aircraft monocoque skeleton......................... 115 4.12 Aircraft semimonocoque skeleton....................... 116 xx List of Figures 4.13 Structural wing sketch............................. 117 4.14 Structural wing torsion box.......................... 117 5.1 Barometric altimeter.............................. 122 5.2 Pitot tube................................... 123 5.3 Gyroscope and accelerometer......................... 124 5.4 Diagram gimbals with accelerometers and gyroscopes........... 125 5.5 Flight and navigation instruments I..................... 127 5.6 Flight and navigation instruments II..................... 128 5.7 Navigation instruments............................ 129 5.8 Instruments T layout............................. 130 5.9 Aircraft cockpit................................. 131 5.10 Aircraft glass cockpit displays........................ 132 5.11 EICAS/ECAM cockpit displays........................ 133 5.12 Flight Management System......................... 134 5.13 Aircraft electrical system........................... 136 5.14 A380 power system components....................... 137 5.15 Aircraft fuel system.............................. 138 5.16 Aircraft hydraulic system........................... 140 5.17 Flight control system............................. 141 6.1 Propeller schematic............................... 149 6.2 Core elements and station numbers in a jet engine............. 151 6.3 Adiabatic process............................... 152 6.4 Types of inlets................................. 154 6.5 Types of jet compressors........................... 155 6.6 Axial compressor................................ 155 6.7 Combustion chamber or combustor...................... 157 6.8 Turbine..................................... 159 6.9 Variable extension nozzle........................... 160 6.10 Convergent-divergent nozzle......................... 161 6.11 Relative suitability of diﬀerent types of jets................. 163 6.12 Turbojet with centrifugal compressor..................... 163 6.13 Turbojet with axial compressor........................ 164 6.14 Turbofan.................................... 165 6.15 Turboprop engines............................... 166 6.16 Afterburner................................... 166 7.1 Wind axes reference frame.......................... 171 7.2 Aircraft forces.................................. 173 7.3 Aircraft forces in a horizontal loop....................... 177 7.4 Aircraft forces in a vertical loop........................ 179 xxi List of Figures 7.5 Take oﬀ distances and velocities....................... 180 7.6 Forces during taking oﬀ............................ 181 7.7 Landing distances and velocities....................... 182 7.8 Take-oﬀ weight components.......................... 185 7.9 Payload-range diagram............................ 187 7.10 Aircraft static stability............................ 188 7.11 Aircraft dynamic stability........................... 189 7.12 Feedback loop control............................. 190 7.13 Longitudinal equilibrium........................... 191 7.14 Longitudinal stability............................. 192 7.15 Eﬀects of elevator on moments coeﬃcient.................. 195 7.16 Forces during taking oﬀ (Problem 7.2).................... 200 7.17 Payload-range diagram (Problem 7.4).................... 217 7.18 Longitudinal equilibrium (Problem 7.5)................... 223 8.1 Aircraft manufacturers.............................. 242 8.2 Airbus A320 family............................... 245 8.3 European percentage share of airline operational costs in 2008...... 250 8.4 Evolution of the price of petroleum 1987-2012................ 251 8.5 C O2 and global warming emissions..................... 259 8.6 Aircraft emissions contributing to global warming.............. 260 8.7 Contrails.................................... 261 8.8 Favorable regions of contrail formation................... 264 8.9 Favorable regions of contrail formation over USA.............. 265 9.1 Schematic conﬁguration of an airport.................... 274 9.2 Typical airport infrastructure......................... 275 9.3 Madrid Barajas layout............................ 279 9.4 FAA airport diagram of O’Hare International Airport............. 280 9.5 Runway designators.............................. 281 9.6 Finger..................................... 283 9.7 Terminal layout................................ 284 9.8 Departure terminal layout.......................... 285 9.9 Terminal conﬁgurations............................ 286 9.10 Airport visual aids............................... 290 9.11 Runway pavement signs............................ 291 9.12 Runway lighting................................ 292 9.13 PAPI...................................... 292 9.14 ILS modulation................................ 294 9.15 ILS: Localizer array and approach lighting................. 294 10.1 Triangle of velocities............................. 301 xxii List of Figures 10.2 Astronomic navigation............................. 303 10.3 ATM levels................................... 308 10.4 Air Traﬃc Control............................... 310 10.5 Air navigation chart.............................. 313 10.6 FIR/UIR structure............................... 314 10.7 Volumes of responsibility........................... 315 10.8 Phases in a ﬂight............................... 318 10.9 En-route lower navigation chart........................ 319 10.10 Instrumental approximation chart....................... 320 10.11 Doppler eﬀect.................................. 326 10.12 Inertial Navigation System (INS)....................... 327 10.13 Accuracy of navigation systems........................ 328 10.14 Scanning beam radiation............................ 331 10.15 VOR-DME................................... 333 10.16 GNSS systems................................. 334 10.17 SBAS Augmentation Systems......................... 335 10.18 LORAN..................................... 336 10.19 NDB...................................... 337 10.20 VOR...................................... 339 10.21 Animation that demonstrates the spatial modulation principle of VORs.. 339 10.22 VOR displays interpretation.......................... 340 10.23 MLS...................................... 342 10.24 Radar...................................... 344 10.25 TCAS...................................... 345 10.26 ADS-B..................................... 347 A.1 Euler angles.................................. 357 xxiii List of Tables List of Tables 1.1 Flag companies and low cost companies.................. 7 3.1 Increase in clmax of airfoils with high lift devices.............. 78 3.2 Typical values for CLmax in wings with high-lift devices.......... 78 3.3 Chap 3. Prob. 2 Data cl − α........................ 84 3.4 Chap 3. Prob. 2 Data cl − cd........................ 84 8.1 Long-haul aircraft speciﬁcations....................... 243 8.2 Medium-haul aircraft speciﬁcations..................... 244 8.3 Regional aircraft speciﬁcations........................ 244 8.4 Airbus 2012 medium-haul aircraft prices.................. 244 8.5 Airbus 2012 long-haul aircraft prices.................... 244 8.6 A320neo family speciﬁcations......................... 246 8.7 B737 MAX family speciﬁcations........................ 246 8.8 Cost structure of a typical airline....................... 248 8.9 Evolution of airlines’ operational costs 2001-2008.............. 250 8.10 Route’s waypoints, navaids, and ﬁxes.................... 263 9.1 Busiest airports by passengers in 2012................... 271 9.2 Busiest airports by passengers in 2011................... 272 9.3 Runway ICAO categories........................... 278 9.4 Runway’s minimum width according to ICAO................ 278 9.5 ICAO minimum distance in airport operations................ 282 9.6 ILS categories................................. 295 10.1 Navigation charts............................... 318 10.2 Navigational systems.............................. 325 10.3 Navigation aids based on situation surface and the technique....... 331 10.4 Classiﬁcation of the navigation aids based on the ﬂight phase....... 331 xxv Part I Introduction The Scope 1 Contents 1.1 Engineering.............................. 4 1.2 Aerospace activity........................... 5 1.3 Aviation research agenda....................... 12 1.3.1 Challenges............................ 12 1.3.2 Clean Sky............................ 13 1.3.3 SESAR.............................. 15 References.................................. 17 The aim of this chapter is to give a broad overview of the activities related to the ﬁeld referred to as aerospace engineering. More precisely, it aims at summarizing brieﬂy the main scope in which the student will develop his or her professional career in the future as an aerospace engineer. First, a rough overview of what engineering is and what engineers do is given, with particular focus on aerospace engineering. Also, a rough taxonomy of the capabilities that an engineer is supposed to have is provided. Second, the focus is on describing the diﬀerent aerospace activities, i.e., the industry, the airlines, the military air forces, the infrastructures on earth, the research institutions, the space agencies, and the international organizations. Last but not least, in the believe that research, development, and innovation is the key element towards the future, an overview of the current aviation research agenda is presented. 3 The Scope 1.1 Engineering Following Wikipedia , engineering can be deﬁned as: The application of scientiﬁc, economic, social, and practical knowledge in order to design, build, and maintain structures, machines, devices, systems, materials, and processes. It may encompass using insights to conceive, model, and scale an appropriate solution to a problem or objective. The discipline of engineering is extremely broad, and encompasses a range of more specialized ﬁelds of engineering, each with a more speciﬁc emphasis on particular areas of technology and types of application. The foundations of engineering lays on mathematics and physics, but more important, it is reinforced with additional study in the natural sciences and the humanities. Therefore, attending to the previously given deﬁnition, engineering might be brieﬂy summarized with the following six statements: to adapt scientiﬁc discovery for useful purposes; to create useful devices for the service of society; to invent solutions to meet society’s needs; to come up with solutions to technical problems; to utilize forces of nature for society’s purposes; to convert energetic resources into useful work. On top of this, according to current social sensitivities, one should add: in an environmentally friendly manner. Following Wikipedia , aerospace engineering can be deﬁned as: a primary branch of engineering concerned with the research, design, development, construction, testing, and science and technology of aircraft and spacecraft. It is divided into two major and overlapping branches: aeronautical engineering and astronautical engineering. The former deals with aircraft that operate in Earth’s atmosphere, and the latter with spacecraft that operate outside it. Therefore, an aerospace engineering education attempts to introduce the following capabilities Newman [3, Chap. 2]: Engineering fundamentals (maths and physics), innovative ideas conception and problem solving skills, the vision of high-technology approaches to engineering complex systems, the idea of technical system integration and operation. 4 1.2 Aerospace activity knowledge in the technical areas of aerospace engineering including mechanics and physics of ﬂuids, aerodynamics, structures and materials, instrumentation, control and estimation, humans and automation, propulsion and energy conversion, aeronautical and astronautical systems, infrastructures on earth, the air navigation system, legislation, air transportation, etc. The methodology and experience of analysis, modeling, and synthesis. Finally, an engineering goal of addressing socio-humanistic problems. As a corollary, an aerospace engineering education should produce engineers capable of the following Newman [3, Chap. 2]: Conceive: conceptualize technical problems and solutions. Design: study and comprehend processes that lead to solutions to a particular problem including verbal, written, and visual communications. Development: extend the outputs of research. Testing: determine performance of the output of research, development, or design. Research: solve new problems and gain new knowledge. Manufacturing: produce a safe, eﬀective, economic ﬁnal product. Operation and maintenance: keep the products working eﬀectively. Marketing and sales: look for good ideas for new products or improving current products in order to sell. Administration (management): coordinate all the above. Thus, the student as a future aerospace engineer, will develop his or her professional career accomplishing some of the above listed capabilities in any of the activities that arise within the aerospace industry. 1.2 Aerospace activity It seems to be under common agreement that the aerospace activities (in which aerospace engineers work) can be divided into seven groups Franchini et al. : the industry, manufacturer of products; the airlines, transporters of goods and people; the military air forces, demanders of high-level technologies; the space agencies, explorers of the space; the infrastructures on earth, supporter of air operations; the research institutions, guarantors of technological progress; the international organizations, providers of jurisprudence. 5 The Scope The aerospace industry The aerospace industry is considered as an strategic activity given that it is a high technology sector with an important economic impact. The Aerospace sector is an important contributor to economic growth everywhere in the world. The european aerospace sector represents a pinnacle of manufacturing which employed almost half a million highly skilled people directly (20.000 in Spain) in 2010 and it continuously spins-out technology to other sectors. About 2.6 million indirect jobs can be attributed to air transport related activities and a contribution of around C250 billion1 (around 2.5%) to european gross domestic product in 2010. Therefore, the aerospace industry is an important asset for Europe economically, being a sector that invests heavily in Research and Development (R & D) compared with other industrial sectors. The aerospace sector is also an important pole for innovation. The aerospace industry accomplish three kinds of activities: aeronautics (integrated by airships, propulsion systems, and infrastructures and equipments); space; and missiles. Grosso modo, the aeronautical industry constitutes around the 80-90% of the total activity. The fundamental characteristics of the aerospace industry are: Great dynamism in the cycle research-project-manufacture-commercialization. Speciﬁc technologies in the vanguard which spin-out to other sectors. High-skilled people. Limited series (non mass production) and diﬃcult automation of manufacturing processes. Long term development of new projects. Need for huge amount of capital funding. Governmental intervention and international cooperation. The linkage between research and project-manufacture is essential because the market is very competitive and the product must fulﬁll severe safety and reliability requirements in order to be certiﬁed. Thus, it is necessary to continuously promote the technological advance to take advantage in such a competitive market. The quantity of units produced a year is rather small if we compare it with other manufacture sectors (automobile manufacturing, for instance). An airship factory only produces tens of units a year; in the case of space vehicles the common practice is to produce a unique unit. These facts give a qualitative measure of the diﬃculties in automating manufacturing processes in order to reduce variable costs. The governmental intervention comes from diﬀerent sources. First, directly participating from the capital of the companies (many of the industries in Spain and Europe are state 1 one billion herein refers to 100.000.000.000 monetary units. 6 1.2 Aerospace activity Flag companies Low Cost companies Operate hubs and spoke Operate point to point Hubs in primary international airports Mostly regional airports Long rotation times (50 min) Short rotation times (25 min) Short and long haul routes Short haul routes Mixed ﬂeets Standardized ﬂeets Low density seats layout High density seats layout Selling: agencies and internet Selling: internet Extras included (Business, VIP lounges, catering) No extras included in the tickets Table 1.1: Comparison between ﬂag companies and low cost companies. owned). Indirectly, throughout research subsides. Also, as a direct client, as it is the case for military aviation. The fact that many companies do not have the critical size to absorb the costs and the risks of such projects makes common the creation of long-term alliances for determined aircrafts (Airbus) or jet engines (International Aero Engines or Eurojet). Airlines Among the diverse elements that conform the air transportation industry, airlines represent the most visible ones and the most interactive with the consumer, i.e., the passenger. An airline provides air transport services for traveling passengers and/or freight. Airlines lease or own their aircraft with which to supply these services and may form partnerships or alliances with other airlines for mutual beneﬁt, e.g., Oneworld, Skyteam, and Star alliance. Airlines vary from those with a single aircraft carrying mail or cargo, through full-service international airlines operating hundreds of aircraft. Airline services can be categorized as being intercontinental, intra-continental, domestic, regional, or international, and may be operated as scheduled services or charters. The ﬁrst airlines were based on dirigibles. DELAG (Deutsche Luftschiﬀahrts- Aktiengesellschaft) was the world’s ﬁrst airline. It was founded on November 16, 1909, and operated airships manufactured by the zeppelin corporation. The four oldest non- dirigible airlines that still exist are Netherlands’ KLM, Colombia’s Avianca, Australia’s Qantas, and the Czech Republic’s Czech Airlines. From those ﬁrst years, going on to the elite passenger of the ﬁfties and ultimately to the current mass use of air transport, the world airline companies have evolved signiﬁcantly. Traditional airlines were state-owned. They were called ﬂag companies and used to have a strong strategic inﬂuence. It was not until 1978, with the United States Deregulation Act, when the market started to be liberalized. The main purpose of the act was to remove government control over fares, routes, and market entry of new airlines in the commercial 7 The Scope (a) Iberia’s A340. © Javier Bravo (b) Iberia Express’s A320. © (c) Ryanair’s B737-800. Muñoz / Wikimedia Commons / Curimedia / Wikimedia Commons / © AlejandroDiRa / GNU FDL. CC-BY-SA-2.0. Wikimedia Commons / CC-BY-SA-3.0. Figure 1.1: Flag companies (e.g., Iberia) and low cost companies (e.g., Iberia Express and Ryanair). aviation sector. Up on that law, private companies started to emerge in the 80’s and 90’s, specially in USA. Very recently, a new phenomena have arisen within the last 10-15 years: the so called low cost companies, which have favored the mass transportation of people. A comparison between low cost companies and traditional ﬂag companies is presented in Table 1.1. It provides a ﬁrst understanding of the main issues involved in the direct operating costs of an airline, which will be studied in Chapter 8. The competition has been so ﬁerce that many traditional companies have been pushed to create their own low cost ﬁlial companies, as it the case of Iberia and its ﬁlial Iberia Express. See Figure 1.1. Military air forces The military air forces are linked to the defense of each country. In that sense, they play a strategic role in security, heavily depending on the economical potential of the country and its geopolitical situation. Historically, it has been an encouraging sector for technology and innovation towards military supremacy. Think for instance in the advances due to World War II and the Cold War. Nowadays, it is mostly based on cooperation and alliances. However, inherent threats in nations still make this sector a strategic sector whose demand in high technology will be maintained. An instance of this is the encouraging trend of the USA towards the development of Unmanned Air Vehicles (UAV) in the last 20 years in order to maintain the supremacy in the middle east minimizing the risk of soldiers life. Space agencies There are many government agencies engaged in activities related to outer space exploration. Just to mention a few, the China National Space Administration (CNSA), the Indian Space Research Organization (ISRO), the Russian Federal Space Agency (RFSA) 8 1.2 Aerospace activity Figure 1.2: International Space Station (ISS). (successor of the Soviet space program), the European Space Agency (ESA), and the National Aeronautics and Space Administration (NASA). For their interest, the focus will be on these last two. The European Space Agency (ESA) was established in 1975, it is an intergovernmental organization dedicated to the exploration of space. It counts currently with 20 member states: Austria, Belgium, Check Republic, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Nederland, Norway, Poland, Portugal, Romania, Spain, Sweden, Switzerland, and United Kingdom. Moreover, Hungary and Canada have a special status and cooperate in certain projects. In addition to coordinating the individual activities of the member states, ESA’s space ﬂight program includes human spaceﬂight, mainly through the participation in the International Space Station (ISS) program (Columbus lab, Node-3, Cupola), the launch and operation of unmanned exploration missions to other planets and the Moon (probe Giotto to observe Halley’s comet; Cassine-Hyugens, joint mission with NASA, to observe Saturn and its moons; Mars Express, to explore mars), Earth observation (Meteosat), science (Spacelab), telecommunication (Eutelsat), as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles (Ariane). The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the civilian space program and for aeronautics and aerospace research. NASA was established by the National Aeronautics and Space Act on July 29, 1958, replacing its predecessor, the National Advisory Committee 9 The Scope for Aeronautics (NACA). NASA science is focused on better understanding of Earth through the Earth Observing System, advancing heliophysics through the eﬀorts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories and associated programs. United States space exploration eﬀorts have since 1958 been led by NASA, including the Apollo moon-landing missions, the Skylab space station, the Space Shuttle, a reusable space vehicles program whose last mission took place in 2011 (see Figure 2.7), the probes (Pioner, Viking, etc.) which explore the outer space. Currently, NASA is supporting the ISS, and the Mars Science Laboratory unmanned mission known as curiosity. NASA not only focuses on space, but conducts fundamental research in aeronautics, such in aerodynamics, propulsion, materials, or air navigation. Infrastructures on earth In order to perform safe operations either for airliners, military aircraft, or space missions, a set of infrastructures and human resources is needed. The necessary infrastructures on earth to assist ﬂight operations and space missions are: airports and air navigation services on the one hand (referring to atmospheric ﬂights); launch bases and control and surveillance centers on the other (referring to space missions). The airport is the localized infrastructure where ﬂights depart and land, and it is also a multi-modal node where interaction between ﬂight transportation and other transportation modes (rail and road) takes place. It consists of a number of conjoined buildings, ﬂight ﬁeld installations, and equipments that enable: the safe landing, take-oﬀ, and ground movements of aircrafts, together with the provision of hangars for parking, service, and maintenance; the multi-modal (earth-air) transition of passengers, baggage, and cargo. The air navigation is the process of steering an aircraft in ﬂight from an initial position to a ﬁnal position, following a determined route and fulﬁlling certain requirements of safety and eﬃciency. The navigation is performed by each aircraft independently, using diverse external sources of information and proper on-board equipment. The fundamental goals are to avoid getting lost, to avoid collisions with other aircraft or obstacles, and to minimize the inﬂuence of adverse meteorological conditions. Air navigation demands juridic, organizational, operative, and technical framework to assist aircraft on air fulﬁlling safe operations. The diﬀerent Air Navigation Service Providers (ANSP) (AENA in Spain, FAA in USA, Eurocontrol in Europe, etc.) provide these frameworks, comprising three main components: Communication, Navigation, and Surveillance (CNS). Meteorological services. 10 1.2 Aerospace activity Air Traﬃc Management (ATM). – Air Space Management (ASM). – Air Traﬃc Services (ATS) such traﬃc control and information. – Air Traﬃc Flow Management (ATFM). A detailed insight on these concepts will be given in Chapter 10. A launch base is an earth-based infrastructure from where space vehicles are launched to outer space. The situation of launch bases depends up on diﬀerent factors, including latitudes close to the ecuador, proximity to areas inhabited or to the sea to avoid danger in the ﬁrst stages of the launch, etc. The most well known bases are: Cape Kennedy in Florida (NASA); Kourou in the French Guyana (ESA); Baikonur en Kazakhstan (ex Soviet Union space program). Together with the launch base, the diﬀerent space agencies have control centers to monitor the evolution of the space vehicles, control their evolution, and communicate with the crew (in case there is crew). Aerospace research institutions The research institutions fulﬁll a key role within the aerospace activities because the development of aviation and space missions is based on a continuos technological progress aﬀecting a variety of disciplines such as aerodynamics, propulsion, materials, avionics, communication, airports, air navigation, etc. The research activity is fundamentally fulﬁlled at universities, aerospace companies, and public institutions. Spain counts with the Instituto Nacional de Técnica Aeroespacial (INTA), which is the spanish public research organization specialized in aerospace research and technology development. It pursues the acquisition, maintenance, and continuous improvement of all those technologies that can be applied to the aerospace ﬁeld. There exist “sister" institutions such the French Aerospace Lab (ONERA), the German Aerospace Center (DLR), or the National Aeronautics and Space Administration (NASA) in the United States of America (USA), just to mention a few signiﬁcative ones. International organizations In order to promote a reliable, eﬃcient, and safe air transportation, many regulations are needed. This regulatory framework arises individually in each country but always under the regulatory core of two fundamental supranational organizations: The International Civil Aviation Organization (ICAO) and the International Air Transport Association (IATA). ICAO was created as a result of the Chicago Convention. ICAO was created as a specialized agency of the United Nations charged with coordinating and regulating international air travel. The Convention establishes rules of airspace, aircraft registration and safety, and details the rights of the signatories in relation to air travel. In the successive 11 The Scope revisions ICAO has agreed certain criteria about the freedom of overﬂying and landing in countries, to develop the safe and ordered development of civil aviation world wide, to encourage the design and use techniques of airships, to stimulate the development of the necessary infrastructures for air navigation. Overall, ICAO has encourage the evolution of civil aviation. The modern IATA is the successor to the International Air Traﬃc Association founded in the Hague in 1919. IATA was founded in Havana, Cuba, in April 1945. It is the prime vehicle for inter-airline cooperation in promoting safe, reliable, secure, and economical air services. IATA seeks to improve understanding of the industry among decision makers and increase awareness of the beneﬁts that aviation brings to national and global economies. IATA ensures that people and goods can move around the global airline network as easily as if they were on a single airline in a single country. In addition to the cited organizations, it is convenient to mention the two most important organization with responsibility in safety laws and regulations, including the airship project and airship certiﬁcation, maintenance labour, crew training, etc.: The European Aviation Safety Agency (EASA) in the European Union and the Federal Aviation Administration (FAA). Spain counts with the Agencia Estatal de Seguridad Aérea (AESA), dependent on the ministry of infrastructures (fomento). AESA is also responsible for safety legislation in civil aviation, airships, airports, air navigation, passengers rights, general aviation, etc. 1.3 Aviation research agenda Aviation has dramatically transformed society over the past 100 years. The economic and social beneﬁts throughout the world have been immense in shrinking the planet with the eﬃcient and fast transportation of people and goods. However, encouraging challenges must be faced to cope with the expected demand, but also to meet social sensitivities. These challenges have led to the formation of the Advisory Council for Aeronautics Research in Europe (ACARE) to deﬁne a Strategic Research Agenda (SRA) for aeronautics and air transport in Europe ACARE. The goals set by the SRA have had a clear inﬂuence on current aeronautical research, delivering important initiatives and beneﬁts for the aviation industry, including among others the Clean Sky Joint Technology Initiative, which pursues a greener aviation, and the Single European Sky ATM Research (SESAR) Joint Undertaking, which pursues a more eﬃcient ATM system. Initiatives in the same direction have been also driven in USA within the Next Generation of air transportation system (NextGen). 1.3.1 Challenges The growth of air traﬃc in the past 20 years has been spectacular, and forecasts indicate that there will continue in the future. According to Eurocontrol, in 2010 there was 9.493 12 1.3 Aviation research agenda million IFR2 ﬂights in Europe, around 26000 ﬂights a day. Traﬃc demand will nearly triple, and airlines will more than double their ﬂeets of passenger aircraft within 20 years time. This continuous growth in demand will bring increased challenges for dealing with mass transportation and congestion of ATM and airport infrastructure. Aviation is directly impacted by energy trends. The oil price peaks in the last period (2008-2011) due to diverse geopolitical crisis are not isolated events, the cost of oil will continue to increase. Dependence on fuel availability will continue to be a risk for air transport, specially if energy sources are held in a few hands. Aviation will have to develop long-term strategies for energy supply, such as alternative fuels, that will be technically suitable and commercially scaleable as well as environmentally sustainable. Climate change is a major societal and political issue and is becoming more. Globally civil aviation is responsible for 2% of C O2 of man made global emissions according to the United Nations’ Intergovernmental Panel on Climate Change (IPCC). As aviation grows to meet increasing demand, the IPCC forecasts that its share of global man made C O2 emissions will increase to around 3% to 5% in 2050 Penner. Non-C O2 emissions including oxides of nitrogen and condensation trails which may lead to the formation of cirrus clouds, also have impacts but require better scientiﬁc understanding. Thus, reducing emissions represents a major challenge, maybe the biggest ever. Reducing disturbance around airports is also a challenge with the need to ensure that noise levels and air quality around airports remain acceptable. 1.3.2 Clean Sky Clean Sky is a Joint Technology Initiative (JTI) that aims at developing a mature breakthrough clean technologies for air transport. By accelerating their deployment, the JTI will contribute to Europe’s strategic environmental and social priorities, and simultaneously promote competitiveness and sustainable economic growth. Joint Technology Initiatives are speciﬁc large scale research projects created by the European Commission within the 7th Framework Programme (FP7) in order to allow the achievement of ambitious and complex research goals, set up as a public-private partnership between the European Commission and the European aeronautical industry. Clean Sky will speed up technological breakthrough developments and shorten the time to market for new and cleaner solutions tested on full scale demonstrators, thus contributing signiﬁcantly to reducing the environmental footprint of aviation (i.e. emissions and noise reduction but also green life cycle) for our future generations. The purpose of Clean Sky is to demonstrate and validate the technology breakthroughs that are necessary to make major steps towards the environmental goals set by ACARE and to be reached in 2020 when compared to 2000 levels: 2 IFR stands for Instrumental Flight Rules and refers to instrumental ﬂights 13 The Scope C O2 emissions en t 35-45% gem a na ht m n d Flig gn a a f t desi r Airc 5-10% esign Aispace d ATM and Bio fuels 45-60% 2010 2050 Figure 1.3: Contributors to reducing emissions. Adapted from Clean Sky JTI. 50% reduction of C O2 emissions; 80% reduction of NOx emissions; 50% reduction of external noise; and a green product life cycle. Clean Sky JTI is articulated around a series of the integrated technology demonstrators: Eco Design. Smart Fixed Wing Aircraft. Green Regional Aircraft. Green Rotorcraft. Systems for Green Operations. Sustainable and Green Engines. Therefore, the reduction in fuel burn and C O2 will require contributions from new technologies in aircraft design (engines, airframe materials, and aerodynamics), alternative fuels (bio fuels), and improved ATM and operational eﬃciency (mission and trajectory 14 1.3 Aviation research agenda management). See Figure 1.3. ACARE has identiﬁed the main contributors to achieving the above targets. The predicted contributions to the 50% C O2 emissions reduction target are: eﬃcient aircraft: 20-25%; eﬃcient engines: 15-20%; improved air traﬃc management: 5-10%; bio fuels: 45-60%. 1.3.3 SESAR ATM, which is responsible for sustainable, eﬃcient, and safe operations in civil aviation, is still nowadays a very complex and highly regulated system. A substantial change in the current ATM paradigm is needed because this system is reaching the limit of its capabilities. Its capacity, eﬃciency, environmental impact, and ﬂexibility should be improved to accommodate airspace users’ requirements. The Single European Sky ATM Research (SESAR) Program aims at developing a new generation of ATM system. The SESAR program is one of the most ambitious research and development projects ever launched by the European Community. The program is the technological and operational dimension of the Single European Sky (SES) initiative to meet future capacity and air safety needs. Contrary to the United States, Europe does not have a single sky, one in which air navigation is managed at the European level. Furthermore, European airspace is among the busiest in the world with over 33,000 ﬂights on busy days and high airport density. This makes air traﬃc control even more complex. The Single European Sky is the only way to provide an uniform and high level of safety and eﬃciency over Europe’s skies. The major elements of this new institutional and organizational framework for ATM in Europe consist of: separating regulatory activities from service provision and the possibility of cross-border ATM services; reorganizing European airspace that is no longer constrained by national borders; setting common rules and standards, covering a wide range of issues, such as ﬂight data exchanges and telecommunications. The mission of the SESAR Joint Undertaking is to develop a modernized air traﬃc management system for Europe. This future system will ensure the safety and ﬂuidity of air transport over the next thirty years, will make ﬂying more environmentally friendly, and reduce the costs of air traﬃc management system. Indeed, the main goals of SESAR are SESAR Consortium : 3-fold increase the air traﬃc movements whilst reducing delays; improvement the safety performance by a factor of 10; 10% reduction in the eﬀects aircraft have on the environment; provide ATM services at a cost to airspace users with at least 50% less. 15 References References ACARE (2010). Beyond Vision 2020 (Towards 2050). Technical report, European Commission. The Advisory Council for Aeronautics Research in Europe. Franchini, S., López, O., Antoín, J., Bezdenejnykh, N., and Cuerva, A. (2011). Apuntes de Tecnología Aeroespacial. Escuela de Ingeniería Aeronáutica y del Espacio. Universidad Politécnica de Madrid. Newman, D. (2002). Interactive aerospace engineering and design. McGraw-Hill. Penner, J. (1999). Aviation and the global atmosphere: a special report of IPCC working groups I and III in collaboration with the scientiﬁc assessment panel to the Montreal protocol on substances that deplete the ozone layer. Technical report, International Panel of Climate Change (IPCC). SESAR Consortium (April 2008). SESAR Master Plan, SESAR Deﬁnition Phase Milestone Deliverable 5. Wikipedia. Aerospace Engineering. http://en.wikipedia.org/wiki/Aerospace_engineering. Last accesed 30 sept. 2013. Wikipedia. Engineering. http://en.wikipedia.org/wiki/Engineering. Last accesed 30 sept. 2013. 17 Generalities 2 Contents 2.1 Classification of aerospace vehicles.................. 20 2.1.1 Fixed wing aircraft........................ 21 2.1.2 Rotorcraft............................. 23 2.1.3 Missiles.............................. 24 2.1.4 Space vehicles.......................... 25 2.2 Parts of the aircraft.......................... 27 2.2.1 Fuselage............................. 27 2.2.2 Wing............................... 28 2.2.3 Empennage............................ 30 2.2.4 Main control surfaces...................... 31 2.2.5 Propulsion plant......................... 32 2.3 Standard atmosphere......................... 33 2.3.1 Hypotheses............................ 33 2.3.2 Fluid-static equation....................... 34 2.3.3 ISA equations.......................... 34 2.3.4 Warm and cold atmospheres.................. 36 2.3.5 Barometric altitude........................ 37 2.4 System references........................... 37 2.5 Problems............................... 39 References.................................. 43 The aim of this chapter is to present the student some generalities focusing on the atmospheric ﬂight of airplanes. First, a classiﬁcation of aerospace vehicles is given. Then, focusing on airplanes (which will be herein also referred to as aircraft), the main parts of an aircraft will be described. Third, the focus is on characterizing the atmosphere, in which atmospheric ﬂight takes place. Finally, in order to be able to describe the movement of an aircraft, diﬀerent system references will be presented. For a more detailed description of an aircraft, please refer for instance to any of the following books in aircraft design: Torenbeek , Howe , Jenkinson et al. , and Raymer et al.. 19 Generalities Fixed-wing aircraft Aerodyne Rotorcraft Airship General aircraft Aerostat Aerostatic ballon Ground-eﬀect crafts Figure 2.1: Classiﬁcation of air vehicles. Adapted from Franchini et al.. 2.1 Classification of aerospace vehicles (Franchini et al. , Franchini and García ) An aircraft, in a wide sense, is a vehicle capable to navigate in the air (in general, in the atmosphere of a planet) by means of a lift force. This lift appears due to two diﬀerent physical phenomena: aeroestatic lift, which gives name to the aerostats (lighter than the air vehicles), and dynamic eﬀects generating lift forces, which gives name to the aerodynes (heavier than the air vehicles). An aerostat is a craft that remains aloft primarily through the use of lighter than air gases, which produce lift to the vehicle with nearly the same overall density as air. Aerostats include airships and aeroestatic balloons. Aerostats stay aloft by having a large "envelope" ﬁlled with a gas which is less dense than the surrounding atmosphere. See Figure 2.2 as illustration. Aerodynes produce lift by moving a wing through the air. Aerodynes include ﬁxed-wing aircraft and rotorcraft, and are heavier-than-the-air aircraft. The ﬁrst group is the one nowadays know as airplanes (also known simply as aircraft). Rotorcraft include helicopters or autogyros (Invented by the Spanish engineer Juan de la Cierva in 1923). A special category can also be considered: ground eﬀect aircraft. Ground eﬀect refers to the increased lift and decreased drag that an aircraft airfoil or wing generates when an aircraft is close the ground or a surface. Missiles and space vehicles will be also analyzed as classes of aerospace vehicles. 20 2.1 Classification of aerospace vehicles (a) Aerostatic ballon. (b) Airship (Zeppelin). Figure 2.2: Aerostats. (a) Glider. (b) Hang glider (with engine). Figure 2.3: Gliders. 2.1.1 Fixed wing aircraft A ﬁrst division arises if we distinguish those ﬁxed-wing aircraft with engines from those without engines. A glider is an aircraft whose ﬂight does not depend on an engine. The most common varieties use the component of their weight to descent while they exploit meteorological phenomena (such thermal gradients and wind deﬂections) to maintain or even gain height. Other gliders use a tow powered aircraft to ascent. Gliders are principally used for the air sports of gliding, hang gliding and paragliding, or simply as leisure time for private pilots. See Figure 2.3. Aerodynes with ﬁxed-wing and provided with a power plant are known as airplanes1. An exhaustive taxonomy of airplanes will not be given, since there exist many particularities. Instead, a brief sketch of the fundamentals which determine the design of an aircraft will be drawn. The fundamental variables that must be taken into account for airplane design are: mission, velocity range, and technological solution to satisfy the needs of the mission. The conﬁguration of the aircraft depends on the aerodynamic properties to ﬂy in 1 Also referred to as aircraft. From now on, when we referred to an aircraft, we mean an aerodyne with ﬁxed-wing and provided with a power plant. 21 Generalities (a) McDonnell Douglas MD-17 (military (b) Lockheed Martin F22 Raptor (ﬁghter). transportation). (c) Antonov 225 (military transportation). Figure 2.4: Military aircraft types. a determined regime (low subsonic, high subsonic, supersonic). In fact, the general conﬁguration of the aircraft depends upon the layout of the wing, the fuselage, stabilizers, and power plant. This four elements, which are enough to distinguish, grosso modo, one conﬁguration from another, are designed according to the aerodynamic properties. Then one possible classiﬁcation is according to its conﬁguration. However, due to diﬀerent technological solutions that might have been adopted, airplanes with the same mission, could have diﬀerent conﬁgurations. This is the reason why it seems more appropriate to classify airplanes attending at its mission. Two fundamental branches exist: military airplanes and civilian airplanes. The most usual military missions are: surveillance, recognition, bombing, combat, transportation, or training. For instance, a combat airplane must ﬂight in supersonic regime and perform sharp maneuvers. Figure 2.4 shows some examples of military aircraft. In the civil framework, the most common airplanes are those dedicated to the transportation of people in diﬀerent segments (business jets, regional transportation, medium-haul transportation, and long-haul transportation). Other civil uses are also derived to civil aviation such ﬁre extinction, photogrametric activities, etc. Figure 2.5 shows some examples of civilian aircraft. 22 2.1 Classification of aerospace vehicles (a) Cessna 208 (Regional) (b) Concorde (Supersonic) (c) Boeing 737-800 (Short-haul) (d) Airbus 380 (Long-haul) Figure 2.5: Types of civilian transportation aircraft. 2.1.2 Rotorcraft A rotorcraft (or rotary wing aircraft) is a heavier-than-air aircraft that uses lift generated by wings, called rotor blades, that revolve around a mast. Several rotor blades mounted to a single mast are referred to as a rotor. The International Civil Aviation Organization (ICAO) deﬁnes a rotorcraft as supported in ﬂight by the reactions of the air on one or more rotors. Rotorcraft include: Helicopters. Autogyros. Gyrodinos. Combined. Convertibles. A helicopter is a rotorcraft whose rotors are driven by the engine (or engines) during the ﬂight, to allow the helicopter to take oﬀ vertically, hover, ﬂy forwards, backwards, and laterally, as well as to land vertically. Helicopters have several diﬀerent conﬁgurations 23 Generalities Figure 2.6: Helicopter. of one or more main rotors. Helicopters with one driven main rotor require some sort of anti-torque device such as a tail rotor. See Figure 2.6 as illustration of an helicopter. An autogyro uses an unpowered rotor driven by aerodynamic forces in a state of autorotation to generate lift, and an engine-powered propeller, similar to that of a ﬁxed- wing aircraft, to provide thrust and ﬂy forward. While similar to a helicopter rotor in appearance, the autogyro’s rotor must have air ﬂowing up and through the rotor disk in order to generate rotation. The rotor of a gyrodyne is normally driven by its engine for takeoﬀ and landing (hovering like a helicopter) with anti-torque and propulsion for forward ﬂight provided by one or more propellers mounted on short or stub wings. The combined is an aircraft that can be either helicopter or autogyro. The power of the engine can be applied to the rotor (helicopter mode) or to the propeller (autogyro mode). In helicopter mode, the propeller assumes the function of anti-torque rotor. The convertible can be either helicopter or airplane. The propoller-rotor (proprotor) changes its attitude 90 [deg] with respect to the fuselage so that the proprotor can act as a rotor (helicopter) or as a propeller with ﬁxed wings (airplane). 2.1.3 Missiles A missile can be deﬁned as an unmanned self-propelled guided weapon system. Missiles can be classiﬁed attending at diﬀerent concepts: attending at the trajectory, 24 2.1 Classification of aerospace vehicles missiles can be cruise, ballistic, or semi-ballistic. A ballistic missile is a missile that follows a sub-orbital ballistic ﬂightpath with the objective to a predetermined target. The missile is only guided during the relatively brief initial powered phase of ﬂight and its course is subsequently governed by the laws of orbital mechanics and ballistics. Attending at the target, missiles can be classiﬁed as anti-submarines, anti-aircraft, anti-missile, anti-tank, anti-radar, etc. If we look at the military function, missiles can be classiﬁed as strategic and tactical. However, the most extended criteria is as follows: Air-to-air: launched from an airplane against an arial target. Surface-to-air: design as defense against enemy airplanes or missiles. Air-to-surface: dropped from airplanes. Surface-to-surface: supports infantry in surface operations. The general conﬁguration of a missile consists in a cylindrical body with an ogival warhead and surfaces with aerodynamic control. Missiles also have a guiding system and are powered by an engine, generally either a type of rocket or jet engine. 2.1.4 Space vehicles A space vehicle (also referred to as spacecraft or spaceship) is a vehicle designed for spaceﬂight. Space vehicles are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration, and transportation of humans and cargo. The main particularity is that such vehicles operate without any atmosphere (or in regions with very low density). However, they must scape the Earth’s atmosphere. Therefore, we can identify diﬀerent kinds of space vehicles: Artiﬁcial satellites. Space probes. Manned spacecrafts. Space launchers. A satellite is an object which has been placed into orbit by human endeavor, which goal is to endure for a long time. Such objects are sometimes called artiﬁcial satellites to distinguish them from natural satellites such as the Moon. They can carry on board diverse equipment and subsystems to fulﬁll with the commended mission, generally to transmit data to Earth. A taxonomy can be given attending at the mission (scientiﬁc, telecommunications, defense, etc), or attending at the orbit (equatorial, geostationary, etc). A space probe is a scientiﬁc space exploration mission in which a spacecraft leaves Earth and explores space. It may approach the Moon, enter interplanetary, ﬂyby or orbit other bodies, or approach interstellar space. Space probes are a form of robotic spacecraft. Space probes are aimed for research activities. 25 Generalities Figure 2.7: Space shuttle: Discovery. The manned spacecraft are space vehicles with crew (at least one). We can distinguish space ﬂight spacecrafts and orbital stations (such ISS). Those missions are also aimed for research and observation activities. Space launchers are vehicles which mission is to place another space vehicles, typically satellites, in orbit. Generally, they are not recoverable, with the exception of the the American space shuttles (Columbia, Challenger, Discovery, Atlantis, and Endevour). The space shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. This system combined rocket launch, orbital spacecraft, and re-entry spaceplane. See Figure 2.7, where the Discovery is sketched. Major missions included launching numerous satellites and interplanetary probes, conducting space science experiments, and 37 missions constructing and servicing the ISS. The conﬁguration of space vehicles varies depending on the mission and can be unique. As a general characteristic, just mention that launchers have similar conﬁguration as missiles. 26 2.2 Parts of the aircraft Vertical stabilizer Horizontal stabilizer Wing Landing Gear Gondola Rudder Fuselage Elevator Flaps Figure 2.8: Parts of an aircraft. 2.2 Parts of the aircraft (Franchini et al. ) Before going into the fundamentals of atmospheric ﬂight, it is interesting to identify the fundamental elements of the aircraft2. As pointed out before, there are several conﬁgurations. The focus will be on commercial airplanes ﬂying in high subsonic regimes, the most common ones. Figure 2.8 shows the main parts of a typical commercial aircraft. The central body of the airplane, which hosts the crew and the payload (passengers, luggage, and cargo), is the fuselage. The wing is the main contributor to lift force. The surfaces situated at the tail or empennage of the aircraft are referred to as horizontal stabilizer and vertical stabilizer. The engine is typically located under the wing protected by the so-called gondolas (some conﬁgurations with three engines locate one engine in the tail). 2.2.1 Fuselage The fuselage is the

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