Electric Propulsion System for Exceptionally Short Takeoff and Landing Electric Air Vehicles
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Electric Propulsion System for Exceptionally Short Takeoff and Landing Electric Air Vehicles Electric Propulsion System for Exceptionally Short Takeoff and Landing Electric Air Vehicles By Parisa Mahvelatishamsabadi, A Thesis Submitted to the School of Graduate Studies in the Partial Fulfillment of the Requirements for the Degree Master Of Science McMaster University c Copyright by Parisa Mahvelatishamsabadi September 18, 2019 McMaster University Master Of Science (2019) Hamilton, Ontario (Mechanical Department) TITLE: Electric Propulsion System for Exceptionally Short Takeoff and Landing Electric Air Vehicles AUTHOR: Parisa Mahvelatishamsabadi (McMaster University) SUPERVISOR: Dr. Ali Emadi NUMBER OF PAGES: xxiii, 157 ii Abstract Over the past few years, electric propulsion systems have been widely used in au- tomotive applications. The next decade is likely to see the electrification of aerial vehicles. In the past 20 years, the passengers demand in the aviation industry has increased by roughly 5% annually. Drastic increment in the passengers de- mand leads to many problems such as emission, noise pollution, airports capacity shortage and high fuel consumption. An electric airplane that can take off and land in extremely short runway can solve all the mentioned problems. Also, an airplane that is smaller and lighter with the ability to take off and land from an extremely short runway can be used as a new transportation system in congested cities and solve the urban road traffic and compensate for people’s time wasted in traffic. With this in mind, in this thesis, the feasibility of converting a conventional fixed-wing direct-drive propeller airplane to an electric extremely short takeoff and landing airplane has been examined. An overview of the history of electric aerial vehicles and flying cars is conducted where some of these vehicles are still under development phase. The main aim of this thesis is to address the effect of takeoff and landing runway length on the elec- tric motor main specifications, including power, torque, and speed. Also, the effect of cruising speed on the motor specifications are investigated, and it is observed that there is a considerable difference between the amount of required power for the cruising mode and takeoff mode. In the end, the impact of the braking system and airplane weight on the landing distance are examined, and It is found that for an airplane with a cruise-efficient propeller, usage of thrust reverser is not practical and hence it is not recommended. Although if the propeller is designed to have iii high efficiency at takeoff and landing, the thrust reverser can be a good solution to make the landing runway shorter. iv Acknowledgements I would like to express my gratitude to Dr. Ali Emadi, my supervisor at McMaster University, for his remarkable guidance, enthusiastic encouragements, great tech- nical assistance, and excellent comments and suggestions he gave me during my research journey. I have learned a lot from his specialized knowledge and his great attitude, and that helps me in my professional career. Thanks are also due to Prof Hugh Liu from the University of Toronto who gave me so many valuable advice, useful critiques and helps in the early stage of this study. I am also grateful to my family and friends, Dr. Masoumeh Omidzohour, Dr. Farhad Mahvelati Shamsabadi, Dr. Siavash Mahvelati Shamsabadi, Shiva Ghasemi, Negar Arabzadeh, and Paria Kargar Samani, for their motivation and support. Without their support, this study would never have been completed. Finally, I would like to dedicate my thesis to all these dear people. v Contents Abstract iii Acknowledgementsv Contents vi List of Figures xi List of Tables xv Declaration of Authorship xvii List of Abbreviations xviii List of Symbols xix 1 Introduction1 1.1 Extremely Short TakeOff and Landing Air Vehicle Applications..2 1.1.1 Airport Shortage Capacity...................2 1.1.2 Urban Road Traffic.......................4 1.2 Challenges in Developing Urban Air Vehicle.............6 1.2.1 Costs...............................6 1.2.2 Lack of sufficient stop stations and ports...........6 vi 1.2.3 Safety..............................7 1.2.4 Noise level............................8 1.3 Thesis Contribution...........................9 1.4 Thesis Outline..............................9 2 Electrified Aircraft 11 2.1 Electric Propulsion Architectures................... 11 2.2 Overview of Electric Flight in the Past and the Future....... 12 2.2.1 General Aviation and Motor Gliders.............. 13 2.2.2 Commuter Aircraft....................... 14 2.3 Why electric propulsion systems?................... 19 2.3.1 Safety.............................. 19 2.3.2 Global Emission......................... 20 2.3.3 Fuel Depletion.......................... 21 2.3.4 Power/Energy.......................... 22 2.3.5 Reverse Operation....................... 23 2.3.6 Efficiency and Energy Consumption.............. 24 2.3.7 Costs............................... 25 2.3.8 Noise Production........................ 26 2.3.9 Design Diversity........................ 26 2.3.10 Preparation time........................ 28 3 Extremely Short Takeoff and Landing Airplane 29 3.1 Takeoff and Landing approaches.................... 29 3.2 Why ESTOL?.............................. 39 3.2.1 Certification process and Air traffic control.......... 40 vii 3.2.2 Safety-in term of control.................... 41 3.2.3 Stop stations and ports..................... 41 3.2.4 Noise............................... 43 3.2.5 Battery Technology....................... 44 3.2.6 Weight.............................. 46 4 Aerodynamic Forces 47 4.1 The International Standard Atmosphere............... 47 4.2 Aerodynamic Forces on Airfoil..................... 49 4.2.1 Angle of Attack......................... 50 4.2.2 Lift Coefficient for an Airfoil.................. 51 4.3 Aerodynamic Forces on a Wing.................... 52 4.3.1 Lift coefficient for a wing.................... 53 4.3.2 Drag coefficient......................... 56 4.3.3 Effect of High Lift Devices on the Lift and Drag Coefficients 57 4.3.4 Effect of Spoilers On Lift and Drag Coefficients....... 62 4.4 Total Lift and Drag Coefficients for an Aircraft In Takeoff and Landing 63 4.5 Thrust Reverser............................. 63 5 Performance Modeling 66 5.1 Equations of Motion.......................... 66 5.2 Steady Level Flight Analysis...................... 67 5.3 Takeoff Analysis............................. 72 5.3.1 Takeoff Ground Roll Distance Analysis............ 72 5.4 Landing analysis............................ 75 5.4.1 Landing Grand Roll Analysis................. 76 viii 6 Electric Aircraft Components Selection and Modeling 79 6.1 Electric Aircraft Components..................... 80 6.1.1 Propulsion System....................... 80 Electric Motor Model...................... 81 Propeller Model......................... 81 6.1.2 Energy Storage: Battery.................... 83 6.1.3 Wing and Airfoil........................ 85 Airfoil Selection......................... 85 Wing Location Selection.................... 86 Wing Geometry......................... 88 High Lift Device Selection................... 88 Spoiler Selection........................ 89 6.2 Total Aircraft Weight.......................... 89 6.3 Total Lift and Zero Drag Coefficients................. 91 6.4 Mission Profile............................. 92 7 Airplane Modelling in Matlab Simulink and Results 95 7.1 Airplane Modelling and Validation.................. 95 7.1.1 Airplane Model for Finding Thrust and Power Requirements 96 7.1.2 Propeller and Electric Motor Operating Points........ 101 7.1.3 Validation Model........................ 108 7.2 Model Evaluation............................ 111 7.3 Results and Discussion......................... 112 7.3.1 Take-off and Landing Distances Effect On Electric Motor’s Specification........................... 113 ix 7.3.2 Cruising Speed Effect on Electric Motor’s Specification... 122 7.3.3 Wheel Brake Coefficient Effect on the Landing Distance.. 125 7.3.4 Maximum Takeoff Weight Effect on the Landing Distance.. 127 8 Conclusion and Future Work 129 A Results: Torque-Speed and Power-Speed Profiles 133 References 148 x List of Figures 1.1 Total passengers boarded worldwide from 2004 to 2017.......3 1.2 US airport distributions with different runway length........3 1.3 Example of comparison between road and air trip..........5 1.4 Proposed stop stations by NASA for VTOL aircraft.........7 2.1 Potential timeline of future aircraft configurations.......... 20 2.2 Fuel price in last 30 years....................... 21 2.3 Comparison of continuous and transient operations for electric ma- chines.................................. 23 3.1 Example of Multi-Copter aircraft................... 31 3.2 The Fairey Rotodyne Y with two separated systemfor taking off and cruising................................. 32 3.3 Tilted-rotor aircraft: Joby S2 configuration during takeoff and cruis- ing modes................................ 33 3.4 Tilted-Wing aircraft: Airbus Vahana configuration during takeoff and cruising modes........................... 33 3.5 Tail-sitter aircraft: AeroVironment SkyTote............. 34 3.6 Number of possible building that can be used as stop stations for takeoff and landing........................... 42 xi 4.1 Temperature distribution in the standard atmosphere........ 48 4.2 Atmosphere properties variations from 0 to 11 km from the sea level 50 4.3 Airplane’s angle of attack....................... 51 4.4 Airfoil lift coefficient versus angle of attack.............. 52 4.5 Wing Configurations.........................