contents Preface xi CHAPTER 1 Introduction and a Brief History of Electric Aircraft 1 1.1 Background 1 1.2 Electrification Trend 2 1.3 Early Electric Flights 3 1.4 The Solar Years 4 1.5 All-Electric and Hybrid-Electric 6 1.6 Way Forward 10 1.7 Book Structure 10 References 11 CHAPTER 2 The Electric Aircraft Paradigm 13 2.1 Scope and Stakes 13 2.2 Route to Electric Aircraft 14 2.3 Electrical Chain Breakdown 17 2.4 Technology Stakes 18 2.5 Conclusion 21 References 21 v
vi CHAPTER 3 Electrification of Aircraft Systems Part I: Power Generation and Distribution, Electrical Networks and Architectures 23 3.1 Conventional Aircraft and Engine Systems 23 3.2 More Electric Engine (MEE) Systems 26 3.3 More Electric Aircraft (MEA) Systems 27 3.3.1 Electrical Power Generation and Distribution 29 References 45 CHAPTER 4 Electrification of Aircraft Systems Part II: Replacement of Pneumatics, Enabling Technologies 49 4.1 Pneumatic Power Generation 49 4.2 Environmental Control System 50 4.2.1 Conventional ECS 51 4.2.2 Electric ECS 54 4.3 Wing Ice Protection System 61 4.4 Enabling Technologies 62 4.4.1 Motors 62 4.4.2 Power Electronics 64 4.5 Conclusions 69 References 70 CHAPTER 5 Electrification of Aircraft Systems Part III: Shift from Hydraulic to Electric-Powered Actuation 73 5.1 Actuation Needs for Power Transmission and Control 74 5.2 General Considerations for PbW Actuation 76 5.2.1 From Power by Pipe Towards Hydraulic-Less PbW 77 5.2.2 PbW Actuator Interface to Electric Power Networks 79 5.2.3 Power Control in PbW Actuators 80
vii 5.2.4 Reliability 83 5.2.5 Integration and Mutualization in PbW Actuation 84 5.3 Local Generation of Hydraulic Power for Actuation 86 5.4 Electrohydrostatic Actuators 87 5.4.1 Functional and Architectural View 87 5.4.2 In-Service EHAs 88 5.4.3 Main Issues for Extensive Use of EHAs 90 5.5 Electromechanical Actuators 91 5.5.1 Functional and Architectural Aspects 91 5.5.2 In-Service EMAs 94 5.5.3 Imperfections of Technological Realization 96 5.5.4 Maturation of EMAs 97 5.6 Challenges with Generalization of PbW Actuation 99 5.6.1 Important Considerations for Use of PbW Actuation 99 5.6.2 Evolution Towards All-PbW Actuation 101 References 102 SAE- and ISO-Related Documents 102 Acronyms 102 CHAPTER 6 Propulsion Options for the Electric Aircraft 105 6.1 Conventional Engines 105 6.1.1 Gas Turbine 106 6.1.2 Turboprop Engine 107 6.1.3 Turbofan Engine 107 6.1.4 Efficiency 111 6.1.5 Noise 112 6.2 Bleedless Engines for the More Electric Aircraft 113 6.3 Propulsion Systems for the Electric Aircraft 114 6.3.1 Enabling Architectures 115 6.3.1.1 Electric Propulsion 115 6.3.1.2 Hybrid-Electric Propulsion 117 6.3.1.3 Distributed Electric Propulsion (DEP) 123 6.3.2 Enabling Technologies 124 6.3.2.1 Motors 124 6.3.2.2 Motor Controls 126
viii 6.3.2.3 Motor and Motor Control Demonstrators 126 6.3.2.4 Materials 127 6.3.2.5 Superconducting Electrical Systems 127 6.3.2.6 Fuel Cells 128 6.3.2.7 Batteries 130 6.4 Conclusion 132 References 133 CHAPTER 7 Aircraft Applications Part I: Electric Propulsion, Electric Taxiing 137 7.1 Battery Electric Propulsion Small General Aviation 138 7.2 Urban Air Transportation 142 7.3 Fuel Cell Electric Propulsion Commuter Aircraft 148 7.4 Battery Electric Propulsion Regional Aircraft 149 7.5 Battery Electric Propulsion Short-Range Aircraft 150 7.6 Electric Taxiing Short-Range Aircraft 151 7.6.1 Operation 152 7.6.2 System Configurations and Performance 152 7.6.3 Nose Landing Gear Actuation 153 7.6.4 Main Landing Gear Actuation 154 7.6.5 Business Models 158 7.7 Conclusions 158 References 158 CHAPTER 8 Aircraft Applications Part II: Hybrid-Electric Propulsion 161 8.1 Fuel Cell Parallel HEP: Commuter Aircraft 161 8.2 Battery Series HEP: Commuter Aircraft 162 8.3 Battery Parallel HEP: Short-Range Aircraft 164 8.4 Battery Series HEP: Short-Range Aircraft 166 8.5 Battery Distributed HEP: Commuter Aircraft 168 8.6 Battery Distributed HEP: Regional Aircraft 169
ix 8.7 Distributed HEP: Short-Range Aircraft 171 8.7.1 No-Battery Partial Turboelectric DHEP 171 8.7.2 Fuel Cell Partial Turboelectric DHEP 172 8.7.3 No-Battery Total Turboelectric DHEP 172 8.7.4 Battery Total Turboelectric DHEP 174 8.8 SMES Total Turboelectric DHEP: Long-Range Aircraft 176 8.9 Conclusions 177 References 178 CHAPTER 9 Maintainability and Operational Overview 181 9.1 Ground Operations 181 9.1.1 Maintenance State of the Art 181 9.1.1.1 Maintenance Planning 182 9.1.1.2 Maintenance Prediction Condition Monitoring 183 9.1.2 Changes for More Electric Aircraft 187 9.1.3 Changes for an Electric Aircraft 188 9.1.4 Airport Operations 189 9.1.4.1 Infrastructure 189 9.1.4.2 Aircraft Handling 190 9.1.4.3 Refueling/Recharging 190 9.1.4.4 Pushback/Taxiing 191 9.2 In-Flight Operations 191 9.2.1 Flight Deck Operations 192 9.2.1.1 Complex Configurations/Licenses 192 9.2.2 Single Pilot Operations 192 9.2.3 Autonomous Flight 193 9.2.4 Pilots as Drone Operators 194 9.2.5 Cabin Operations 196 References 197 CHAPTER 10 Performance and Business Value of Electric Aircraft 199 10.1 Airline Cost Structure 199 10.2 Aircraft Fuel Costs 202
x 10.3 Airline Fuel Efficiency 203 10.4 Business Aviation 205 10.5 Short-Range Aircraft 209 10.6 Long-Range Aircraft 217 10.7 Regional Aircraft 220 10.8 General Aviation 221 10.9 Cost of Ownership 225 10.10 Environmental Footprint 226 References 230 Conclusion 233 About the Authors 235 Index 237