PDR Deployable Small UAV Explorer (D–SUAVE) Customer: Kamran Mohseni University of Colorado at Boulder Fall 2006 D-SUAVE Team 1. 2. 3. 4. 5. 6. 7. 8. David Goluskin* Michael Lapp* Burhan Muzaffar* Jastesh Sud* Brandon Bobian Nathan Sheiko Yoshi Hasegawa Miranda Mesloh * Presenting 2 Overview Objective Mission Overview Deployment Aerodynamics Structures Propulsion Electronics Project Plan Major Risk Assessments Summary References Appendices 3 Primary Objective “To design, fabricate, integrate and verify a RC controlled UAV capable of being remotely deployed from the ARES aircraft and flying a specific flight pattern.” 4 Feedback 1. 2. 3. 1. 2. 3. 4. 5. 6. 7. 8. 9. Primary Factors Requirement flow down Stability of airplane during deployment Deployment scenarios affect the configuration selected Where do we deploy from? Secondary Factors What is the expected data transfer or collection rate? Under what atmospheric conditions the system should be able to operate What supports the mass determination? Required deployment force and acceleration the aircraft must withstand Why a Micro aerial vehicle? What is the detail of the mission? Overestimating propeller efficiencies Sketches/pictures of the possible configurations Who will pilot the vehicle? Requirements Flow Diagram Mission Spatial Resolution Lap Pattern Turn Radius Spatial Range Temporal Readings Sensors Resolution per Location Lap Distance Velocity Lap Time Number Of Laps Endurance Carrier Vehicle Cruise Cruise Empty Vehicles Stall Velocity Drag Mass per Carrier Velocity Sensor Box Mass, Vehicle and Size and Placement Package Mass Deployment Velocity Data Collection Driving Factors Carrier Vehicle Driving Factors Requirements 6 Mission Profile Carrier Vehicle ARES Cruise velocity 25 m/s Cruise drag 12 N Empty wet mass 8.2 kg Stall Velocity 17 m/s Maximum internal payload 3.2 kg 7 5 min/lap, 4 laps 600 m 100 m Mission Path 8 Requirements Parameter Requirement Motivation Deployment Transition to stable cruise after being deployed at 20 m/s ARES stall velocity is 17 m/s Cruise Velocity 12 m/s 5 min/lap, 3600 m/lap Endurance 25 min 5 min/lap, 4 laps, 5 min for safe return Turn Radius 50 m turn 180° over 100 m Vehicle and Package Mass 565 g ARES performance, historical payload mass fractions Payload Mass 75 g Customer-estimated mass of self-powered payload box containing temperature, pressure and humidity sensors Payload Dimensions Not yet determined Customer-estimated dimensions of payload box Payload Location Bottom of payload box must be in contact with the freestream Atmospheric sensors must have access to the air 9 Design Process Lighter than Air Fixed Wing Rocket Unfolded Piggyback Folded in Tube Folded Piggyback Low Aspect Ratio Conventional Canard Helicopter Flying Wing Electronics/Comm/Sensors Glider Bi-Plane Propulsion/Power Supply Vehicle Design Prop Launchable/Packageable Structure Configuration Motor Folding or Non Folding Gear Box Speed Control Outrunner Wing Folding Material Stability Controllability Dihedral Control Surfaces Membrane Ailerons Rudder and Elevator only Link Design Alternatives Packagability Endurance Speed Maneuverabilit y Mass Balloon Must be deflated to fit in tube Limited by leaks Controlled by wind 0-1 m turn radius ~100 g Airship Must be deflated to fit in tube 13-16 min typical ~10 m/s 0-1 m turn radius 100-800 g Glider Wings fold 2-5 min typical ~9 m/s 2-3 m turn radius typical ~50 g Helicopter Blades fold 5-10 min typical ~13 m/s 0 turn radius ~300-1500 g Fixed Wing Wings fold 15-20 min typical 15-20 m/s 8-11 m turn radius typical ~50 g Rocket Small size 0.3-0.5 min typical Very fast 75-90 m turn radius typical ~110 g 11 Link Cruise Velocity Endurance USAFAMAV I Rollup Wing, 74 cm Span 18 m/s Wind Tunnel Verification Only USAFAMAV II Folding Wing, 205 cm Span 18 m/s 15 min UF Flexible Wing MAV 11 cm span 13 m/s Never Flown CMAV Folding Wing, 50 cm Span 20 m/s Never Flown UF Morphing Wing MAV 61 cm Span 11 m/s 20 min DART MAV 30 cm Span 18 m/s Unstable Acceptable Packagablity Unacceptable Vehicle Good Existing Packagable MAVS *Payload data generally unavailable 12 Deployment Packaging Methods Method Complexity Drag Loads on Vehicle Folding not required Drag on vehicle and deployment mechanism High aerodynamic loads on the vehicle’s wings during carrier flight Folded Piggy-back Wing folding mechanism required Drag on compact vehicle and deployment mechanism Moderate aerodynamics loads on vehicle during carrier flight Folded in a tube -Wing folding mechanism required -Tube and tube deployment mechanism required Drag on smooth package only No aerodynamic loads on the vehicle during carrier flight Unfolded PiggyBack 14 Vehicle Deployment Methods Vehicle Deployment Method Parachute Spring or Elastic Dynamic Pressure Peak Acceleration Complexity Orientation Control Launch Risks 12-14 g’s to slow to 21 m/s -Front and back of tube must open -Parachute must release Parachute force maintains orientation after leaving tube -Line tangle -Parachute could slow vehicle too much 2-4 g’s to slow to 21 m/s -Back of tube must open -Elastic mechanism needed No orientation control after leaving tube Elastic snag 0.1-0.2 g’s Front and back of tube must open No orientation control after leaving tube Minimal deceleration while in the tube 15 Wing Deployment Folding Configuration Required Tube Diameter Complexity Stability Side By Side dtube 2cmax Simple hinges No uneven roll moment cmax dtube 2cmax Angled pivots or flexible wings Uneven roll moment during deployment Overlapped Wing Deployment Mechanism Deployment Rate Complexity Mass Stability Mechanism may be added to guarantee symmetrical deployment Symmetrical deployment guaranteed Elastic or Spring-Driven Dual Pivot Exert largest structural loads Simple mechanism Elastic bands, mounting hardware, release mechanism Servo Dual Pivot Servos are not designed for high speed Electronics and servo linkages required Servo is heavier than a release mechanisms Carpenter Tape Hinges Provide large unfolding moments Hinges may need to be made from composites Hinges, release mechanism Symmetrical deployment not guaranteed 16 Tube Drop Verification Verification Test Manufacturing Complexity Logistical Complexity Similarity to Actual Drop Risk of Crash Low ground clearance Car Pole Drop Build pole system and attach to car Find test location Speed can be matched, but ground clearance is lower Building Launch Build launch system Find building for launch Speed may be difficult to reproduce Moderate ground clearance UAV Drop Integrate tube onto UAV Coordinate with UAV pilot Identical High ground clearance 17 Car/Pole Verification Vcar = VUAV Pole height dictated by drop distance 18 Package Configuration 19 Aerodynamics Possible Configurations Low-Aspect Ratio Aircraft 0.1 0.05 3.5 L over D Wing z-coordinate 4 0 -0.05 -0.1 3 0.1 0 0.2 -0.1 Wing y-coordinate 0.1 0 Assumptions: 1. Small angle of attack 2. Thin airfoil 3. Estimated Parasite drag Wing x-coordinate 2.5 0 5 10 15 alpha (deg) 21 Possible Configurations Flying Wing 8 0.1 7 0 6.5 L over D Wing z-coordinate 7.5 -0.1 0.4 6 5.5 0.2 5 0 0.4 -0.2 Wing y-coordinate -0.4 Assumptions: 1. Small angle of attack 2. Thin airfoil 3. Estimated Parasite drag 0.2 0 Wing x-coordinate 4.5 4 0 5 10 15 alpha (deg) 22 Possible Configurations Conventional Aircraft 10 0.1 8 0 L over D Wing z-coordinate 9 -0.1 0.4 7 6 5 0.2 0 4 -0.2 Wing y-coordinate -0.4 Assumptions: 1. Small angle of attack 2. Thin airfoil 3. Estimated Parasite drag 0.2 0 Wing x-coordinate 3 0 5 10 15 alpha (deg) 23 Possible Configurations Canard Aircraft 7.5 6.5 6 0.1 L over D Wing z-coordinate 7 0 -0.1 0.4 5.5 5 4.5 0.2 4 0 0.4 0.2 -0.2 Wing y-coordinate -0.4 0 -0.2 Assumptions: 1. Small angle of attack 2. Thin airfoil 3. Estimated Parasite drag Wing x-coordinate 3.5 3 0 5 10 15 alpha (deg) 24 Possible Configurations Biplane 8 0.1 7 0 L over D Wing z-coordinate 9 -0.1 0.4 6 5 0.2 4 0 -0.2 Wing y-coordinate 3 -0.4 0.2 0 Wing x-coordinate 2 0 5 10 15 alpha (deg) Assumptions: 1. Small angle of attack 2. Thin airfoil 3. Estimated Parasite drag 25 Configuration of Aircraft Configuration Packagability Efficiency Stability Manufacturability Experience Low-AR Wings must bend High induced drag Small moment arm of control surfaces Membrane wing is simple to construct No experience Flying Wing Wings must overlap when they fold All surfaces generate lift Difficult to achieve pitch stability All components must be inside wing structure Flying wing lab in 3111 Conventional Wing can sweep back in multiple configuration All surfaces produce parasite drag, but not all produce lift -Large moment arm for tail -Flexible CG placement Must construct wing, fuselage, tail and control surfaces Design and modeling experience in many classes Canard -Longer package if wings fold back -Unstable transition if wings fold forward All surfaces produce parasite drag, but not all produce lift Biplane Small planform area, but greater height Greatest parasite drag Similar to conventional Similar to conventional Must construct wing, fuselage, canard, and control surfaces Must construct two wings No experience, but similar to conventional configuration No experience, but similar to conventional configuration 26 Wing Sizing Calculate span required to lift vehicle for a given chord: Guess b c Lifting Line CL S no L b 12 Span Required for Lift Maximum Span Allowed by Tube 11 10 14.1 cm 9 AR Span (cm) yes Aspect Ratio for Varying Chords Span Required and Maximum Span for Varying Chords 150 8.6 cm L=W ? 100 8 7 6 50 10 12 14 Chord (cm) 16 18 5 9 10 11 12 Chord (cm) 13 14 27 L/D Without Induced Drag Airfoil Data Lifting Line Approximation 40 40 35 30 30 20 Aquila Verbitsky BE50 Clark Y Cody RobertsonCR001 10 EpplerE387 0 0 2 4 6 8 Angle of Attack [ - deg] 20 15 10 5 0 S 3014 -2 L/D L/D 25 10 -5 -2 0 2 4 6 8 Angle of Attack [ -deg] 10 28 L/D With Induced Drag Airfoil Data Corrected for Di (e = 0.6, AR = 8) Lifting Line Approximation 15 15 10 10 L/D L/D 5 5 0 Aquila Verbitsky BE50 Clark Y Cody RobertsonCR001 0 EpplerE387 -5 -4 -5 S 3014 -2 0 2 4 6 Angle of Attack [ - deg] 8 10 -10 -4 -2 0 2 4 6 Angle of Attack [ -deg] 8 10 29 Required CL CL Level Flight 0.72 CL Steady Level Turn 0.7 0.68 C L 0.66 0.64 0.62 0.6 0.58 0.56 0.09 0.1 0.11 0.12 Chord [m] 0.13 0.14 30 Link Tail Configurations Configuration Packagability Efficiency Stability Experience Moderate wetted area No coupling of pitch and yaw control No experience, but similar to conventional configuration No experience T-Tail Horizontal tail is not near center V-Tail Tail surface extend up as well as sideways Moderate wetted area Coupling of pitch and yaw control Conventional Horizontal tail is near center Moderate wetted area No coupling of pitch and yaw control H-Tail Vertical tails are not near center Small wetted area No coupling of pitch and yaw control Computed controllability in ASEN 3128 No experience, but similar to conventional configuration 31 Control Surface Configuration Control Surface Configuration Effect on Deploying Wing Controllability Complexity Manufacturability Aileron, Elevator & Rudder Servos complicate wing deployment Good controllability on all 3 rotational axes 4 surfaces Many parts to construct Aileron & Rudder Servos complicate wing deployment 3 surfaces Must integrate control mechanisms into wing Aileron & Elevator Servos complicate wing deployment Poor yaw control 3 surfaces Must integrate control mechanisms into wing Elevator & Rudder No servos in wings Poor roll control 2 surfaces Easy to construct Poor pitch control 32 Structures Spar Structure b/2 MS MS α = 12.6 rad/s2 ω average = 3.15 rad/s Carbon Fiber Tubes (OD x ID) cm Shear stress computed (MPa) Allowable Shear Stress (MPa) Mass (g) (b/2) 0.318 x 0.188 TBD 65.5 3.4 g 0.584 x 0.366 TBD 65.5 11.4 1.27 x 0.366 TBD 65.5 20 34 Spar Materials Comparison of Solid Cylider Spars 25 Aluminum Carbon Fiber Titanium Balsa Composite Mass (g) 20 15 10 5 0 2 4 6 8 10 12 14 16 18 20 Vmax (mm) 35 Wing Materials maximum deflection (mm) 5 4 3 2024-T3 Al 7075-T6 Al Aramid-Epoxy S-Fiberglass-Epoxy Carbon-Epoxy Blue Foam Balsa 2 1 0 0 2 4 radius of gyration (mm) 36 Propulsion Outrunner vs Gearbox System Outrunner DC Motor with a Gearbox Additional Mass Efficiency Complexity Availability None Slightly lower motor and propeller efficiencies Motor selection Available from local hobby shops >10 g Slightly higher motor and propeller efficiencies, but ηgb < 0.93 Gearbox selection and mounting Gearheads are largely motor-specific 38 Propeller Location C.G. Wing Deployment Interference Crash Consequences Puller Easily achieve stable C.G. location None Could damage prop/motor Pusher Difficult to move C.G. far enough forward Prop/motor could interfere with folded wings Less likely to damage prop/motor Propeller Location 39 Selected Motors ηprop Required Battery Capacity (mAh) Total Mass (g) 66.70% 52.90% 517 66.4 65.46% 59.48% 470 83.5 Motor Mass (g) Max Current (A) Recommended Propeller (in x in) Back of Efficiency Curve? ηmotor Komodo KH220411 24 11 7x3.5 Yes Model Motors 2208/26 45 11 7x4 Yes Motor Assume: ηesc = 95% Model Motors 2208/26 Efficiency Curve 0.8 0.7 0.7 0.6 0.6 Efficiency Efficiency Komodo KH220411 Efficiency Curve 0.8 0.5 0.4 0.5 0.4 0.3 0.3 0.2 0.2 0.1 0 0.2 0.4 0.6 0.8 1 RPM 1.2 1.4 1.6 1.8 2 4 x 10 0.1 0 0.2 0.4 0.6 0.8 1 RPM 1.2 1.4 1.6 1.8 2 4 x40 10 Battery Types Battery Capacity vs. Mass 350 300 Mass [grams] 250 200 150 100 50 0 0 500 1000 1500 2000 2500 3000 3500 4000 Capacity [mAh] 41 Electronic Speed Control ESC Mass [g] Max Continuous Current [A] Castle Creations Phoenix 10 6 10 Yes BP 7.1 10 Yes Jeti 10 12 Yes BEC? 42 Risk Reduction Experiment Verify Endurance Requirement Test entire propulsion system in the ITLL wind tunnel Test battery capacity RC Watt Meter Verify combined motor/prop and ESC efficiencies 43 Electronics Electronics Flow Chart Electronics/Sensors Options Power Source One Source Two Sources Real Time Data Transmission Requirement Verification On Board Sensors Recover Recorded Data Radio Control From Ground Radar Gun Direct to BEC/Servos Flight Dynamics Board Assistance Stop watch and Visual 45 Ground Station Setup 46 Communications Setup Motor Battery ESC/BEC Servos Flight Dynamics Board Receiver GS 47 Onboard Sensors Onboard Sensor Flight Dynamics Board Pitot Tube Availability Complexity Sensor Output Developed at CU -GPS signal interference -Software interface necessary -Yields groundspeed -Can be used for autonomous flight later Not readily available -Rigorous calibration -Extremely susceptible to damage upon landing -Yields airspeed 48 Flight Dynamics Board Dimensions: 4” x 1.25” Mass: 30 g Power/Current: ~1.50 W /125 mA Components GPS Receiver XB-Pro TX Rate Gyro Microchip Pressure Gauge Cost: ~$500 49 Servos Maker/Model Mass (g) Torque (N-m) Cost ($) Gear material System 3000 TS-5 S3K 9.6 .15 21.99 Nylon Hitec HS-50 6.4 .06 27.48 Nylon Hitec HS-55 8 .127 19.95 Nylon Hitec HS56HB 10.7 .06 24.99 Nylon JR NES 375 Micro Servo 9 .127 40.6 Metal 50 Receivers PCM 1024 Receivers Mass (g) Current Draw (mA) Voltage (V) Cost ($) Range (m) Futaba R148DP 30.4 14 4.8 - 6 129.99 3600 Futaba R138DP 50 13 4.8 - 6 99.99 3600 Futaba R146iP 16.5 13 4.8 - 6 79.99 300 51 Energy Budget Component Required Battery Capacity (mAh) Motor 517 Flight Dynamics Board 52 Servos 50 Receiver 6 Subtotal 625 Total (SF = 1.2) 750 52 Battery Selection Battery (LiPoly) Capacity [mAh] Voltage [V] Mass [g] Rating [C] Hyperion LiteStorm VX 800 11.1 62 20 Apogee 800 11.1 65 20 Venom Racing 800 11.1 84 20 53 Mass Budget Subsystem Item Description Aerodynamics Wing 45-80 Wing Spars 10-15 Fuselage 10-15 Backbone Spar 5-10 Tail 10-20 Wing Deployment Mechanism 20-50 Fasteners 5-10 Dummy Payload 75 Receiver 30 Servos Electronics 10-20 Flight Dynamics Board 30 GPS Antenna 10 Connectors/Wires Battery Propulsion Mass [g] Propeller 10-20 62 5-10 Motor 24 ESC 6 Total Vehicle Mass 367 - 487 Remaining Mass for Tube 78 - 198 Total Mass 565 54 Project Plan Preliminary Cost Analysis Subsystem Aerodynamics Electronics Item Description Quantity Cost ($) Wing/Fuselage Material N/A 200 Flight Dynamics Board 1 500 RC Controller 1 300 Onboard Receiver 1 130 Servos 2 25 GPS Antenna 1 30 TBD TBD Battery 3 150 Propeller 5 30 Motor 2 150 Li-polymer Battery Charger 1 120 Wattmeter 1 55 ESC 1 50 Tube/Pole 1 200 Connectors/Wires/Other Propulsion Deployment Total (With ~50% Margin) 2500 56 Subsystem Interdependence Electronics Ground Station Vehicle Receiver RC Transmitter Propulsion Wing Flight Dynamics Board Data Receiver Battery Control Surfaces Servos Speed Controller Fuselage Motor Swing Mechanism Propeller Tube 57 D-SUAVE 1. Project Management 2. Systems Engineering 3. Vehicle Design 4. Propulsion 5. Electronics & Comm. 6. Testing & Verification 1.1. Organization 2.1. Design Orientation 3.1. Configuration 4.1. Motor Selection 5.1. Sensors 6.1. Endurance 1.2. Schedule 2.2. Subsystem Coordination 3.2. 4.2. Propeller Aerodynamics Selection 5.2. Controls 6.2. Velocity 1.3. Planning 2.3. Project Feasibility 1.4. Group Dynamics 3.3. Lift-to-drag 4.3. Driver Selection 5.3. Comm. System 6.3. Mass 3.4. Stability 4.4. Battery Selection 5.4. Power for Electronics 6.4. Deployment 3.5. Wing Area 3.6. Structure 3.7. Deployment 6.5. Propulsion Work Breakdown Schedule Gantt Chart Advisor Donna Gerren Advisor Lee Peterson Project Manager Burhan Muzaffar Aero / Advisor Michel Lesoinne Systems Engr. Nathan Sheiko Fabrication Engr. David Goluskin CFO Jastesh Sud Safety Engineer Yoshi Hasegawa Deployment Vehicle Design Michael Lapp Nathan Sheiko Burhan Muzaffar Michael Lapp Yoshi Hasegawa Assistant P.M Miranda Mesloh Webmaster Brandon Bobian Structure Electronics Propulsion Jastesh Sud Brandon Bobian Miranda Mesloh David Goluskin Nathan Sheiko Major Risk Assessments Risk Consequence Plan to Avoid Vehicle does not transition to stable flight Vehicle crashes and must be repaired Verify first by hand launch over soft ground High drag Endurance requirement not met Minimize drag sources and model thoroughly Vehicle unstable Vehicle design must be altered Glide test at early stage and design movable CG Insufficient controllability Control surfaces must be resized Ground test RC control and size surface with SF Low efficiency propeller Endurance requirement not met Test propulsion system in wind tunnel Pole is structurally unsound Deployment test cannot be performed Design pole with large SF 61 Link Design Choice Summary Packaged in a tube Fixed wing aircraft Conventional configuration Deploy using dynamic pressure Wings fold side-by-side Wings deployed by elastic or springs Elevator and rudder Conventional tail Outrunner motor Pulling propeller On-board sensors for verification 62 Acknowledgements Bill Pisano: Assisted with electronics setup Dale Lawrence: Helped redefine the project Donna Gerren: PAB Advisor Jeremiah Hall: Blade element code for propulsion Kamran Mohseni: Project customer Lee Peterson: PAB Advisor Michel Lesoinne: Assisted with aerodynamics numerical analysis Sedat Biringen: Advised on aerodynamics numerical modeling 63 References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. Abdulrahim, Mujahid et. al., Flight Testing A Micro Air Vehicle Using Morphing For Aeroservoelastic Control<mav.mae.ufl.edu/mujahid/publications/sdm04.pdf>. Airfoil Data, 18 Sept. 2006, <http://www.nasg.com/afdb/index-e.phtml>. Askeland, Donald. Essentials of Materials Science and Engineering, Ontario: Nelson, 2004. Cengel, Yunus. Introduction to Thermodynamics and Heat Transfer, New Jersey: McGraw Hill, 1996. Corke, Thomas. Design of Aircraft. New Jersey: Prentice Hall, 2003. Futaba Receivers, 27 Sept. 2006, <http://www.hoverhobbies.com>. Graphite Store, 13 Oct. 2006 <http://www.graphitestore.com>. Hall, J., Mohseni, K., Lawrence, D. A., Investigation of Variable Wing-Sweep for Applications in Micro Air Vehicles. Boulder, CO: University of Colorado, 2005. Lawrence, Dale A., Mohseni, Kamran, Efficiency Analysis for Long-Duration Electric MAVs. University of Colorado, Boulder, CO, 2005. Micro Servos, 18 Sept. 2006 <http://www.modelflight.com>. Peak Efficiency, <http://www.peakeff.com>. Schmidt, Louis. Introduction to Aircraft Flight Dynamics. Reston: AIAA, 1998. Shevell, Richard., Fundamentals of Flight, 2nd Ed., New Jersey: Prentice Hall, 1989. Tower Hobbies, 18 Sept. 2006 <http://www.towerhobbies.com>. Vable, Madhukar. Mechanics of Material. New YorK: Oxford University Press, 2002. Warren F. Phillips, Mechanics of Flight. Hoboken, NJ: John Wiley & Sons, 2004. 64 Appendices Number of back up slides - 61 Risk assessment Design Alternatives Deployment Aerodynamics Structure Propulsion Electronics Project Plan (RA) (DA) (DP) (AD) (ST) (PP) (EC) (PP) 65 Deployment Risk Assessment Low Likelihood Mid High Vehicle does not transition to stable flight Vehicle does not deploy Low Wings do not deploy Mid Consequence High 66 Link Deployment Risk Avoidance Risk Consequence Plan to Avoid Vehicle does not transition to stable flight Vehicle crashes and must be repaired Verify first by hand launch over soft ground Wings do not deploy Vehicle crashes and must be repaired Verify wing deployment first on ground Vehicle does not deploy from tube Deployment cannot be verified Verify tube deployment first on ground 67 Vehicle unstable Landing damages vehicle High drag Insufficient controllability Low Likelihood Mid High Aerodynamics Risk Assessment Insufficient lift Low Mid Consequence High 68 Aerodynamics Risk Avoidance Risk Consequence Plan to Avoid High drag Endurance requirement not met Minimize drag sources and model thoroughly Vehicle unstable Vehicle design must be altered Glide test at early stage Insufficient controllability Control surfaces must be resized Ground test RC control and size surface with SF Insufficient lift Wing must be resized Size wing with SF Landing damages vehicle Vehicle must be repaired Design for low stall speed 69 High Manufacturing difficulties Likelihood Mid Aeroelasticity impairs performance Low Structure Risk Assessment Wing deployment damages wing structure Low Mid Consequence High 70 Structure Risk Avoidance Risk Consequence Plan to Avoid Manufacturing difficulties Delay in schedule and increase in costs Use well-known techniques and budget time for mistakes Aeroelasticity impairs performance Aerodynamic performance impaired Design for maximum allowable deflections rather than yield strength Wing deployment damages wing structure Vehicle must be repaired and wing structure must be redesigned Design structure with SF and ground test deployment 71 High Propulsion Risk Assessment Likelihood Mid Insufficient thrust Low Low efficiency Insufficient battery capacity Low Mid Consequence Overheating High 72 Propulsion Risk Avoidance Risk Consequence Plan to Avoid Low efficiency Endurance requirement not met Test propulsion system in wind tunnel Insufficient thrust Velocity requirement not met Test propulsion system in wind tunnel Overheating Motor and electronics damaged Monitor motor temperature during wind tunnel testing Insufficient battery capacity Endurance requirement not met Confirm battery capacity on ground 73 Electromagnetic noise due to motor Poor electrical connections Low GPS signal interference Likelihood Mid High Electronics Risk Assessment Unable to receive real-time data -Transmission range exceeded -Insufficient servo power RC signal interference Low Mid Consequence High 74 Electronics Risk Avoidance Risk Consequence Plan to Avoid Poor electrical connections Control and sensor failure Ground test all possible connections GPS signal interference Velocity requirement not verified Insulate antenna from below and ground test Electromagnetic noise due to motor Control and sensor failure Ground test electronics with motor running Transmission range exceeded Loss of control and possible crash Ground test range Insufficient servo power Insufficient control Design with SF and verify in wind tunnel Unable to receive realtime data Velocity cannot be verified in real time Develop ground station software and ground test Insufficient control Use a high quality transmitter and receiver and ground test RC signal interference 75 Configuration of Aircraft - (DA) Configuration Packagability (40%) L over D (25%) Stability (20%) Manufacturing (15%) Weighted Total (100%) Low-AR 5 1 1 5 3.2 Flying Wing 4 3 2 4 3.35 Conventional 3 5 4 2 3.55 Canard 2 2 3 3 2.35 Biplane 1 4 5 1 2.55 76 Design Alternatives – (DA) Packagability (40%) Aircraft Length Endurance (20%) Time Aloft Speed (20%) Maneuverability (10%) Speed Turn Radius Overall Mass (10%) Weighted Total Mass Balloon 2 5 1 4 5 2.9 Airship 2 4.5 3 4 3 3 Glider 4 2 2.5 3.5 2 3.05 Helicopter 4 3 4 4.5 3 3.75 Fixed Wing 4 4.5 4.5 3 2 3.9 Rocket 5 1 5 1 5 3.8 Best 77 Available Design - (DA) Aircraft Overall Mass Maneuverability Packagability Endurance Speed Mass (kg) Turn Radius (m) Length (m) Time Aloft (min) Speed (m/s) Balloon 0.10 0.00 collapse limited by leaks 0.00 Airship 0.1-0.8 0.00 collapse 15.00 10.00 0.50 2.64 0.80 3.00 9.00 0.3-1.5 0.00 0.80 12.00 13.00 Fixed Wing 0.50 10.00 0.80 15.00 15-20 Rocket 0.11 81.63 0.47 0.43 50.00 Glider Helicopter 78 Deployment Calculations – (DP) Option Peak Force (N) Peak Complexity Acceleration (# Parts) (Gs) Parachute 58.11 13.94 3 Spring 12.50 3.00 2 Elastic 9.50 2.28 2 Track 4.85 1.16 4 79 Force – (DP) 80 Force – (DP) 81 Stall Speed – (DP) 82 Aerodynamics Analysis Model – (AD) Span Chord Taper Twist Induced Drag Parasite Drag Spanwise CL Distribution Define Geometry Calculate Circulation Wing Loading Drag Lift-to-Drag Airfoil Data Flight Performance Characteristics Stability Derivatives Dynamic Derivatives Twist Angle – (AD) 45 40 L over D 35 30 25 20 15 10 -20 -10 0 10 twist angle (deg) 20 84 Configuration of Aircraft – (AD) Flying Wing vs Conventional Focus on Longitudinal Controllability (Fast pitching behavior of the aircraft at the trim condition) Assumption: No Control Effect , M I y M Q S cCm c Cm Cm 2V Cm Cmq c I y Q S c C m C mq Q S c C m 0 2V Eq.(1) 85 Configuration of Aircraft – (AD) Flying Wing vs Conventional Cmq lH CL 2.20VH c H Cm lH CL 2.20VH c H Flying wing: No damping terms in Eq. (1) Conventional Aircraft: Damping terms in Eq. (1) Conventional Aircraft is more controllable. 86 Airfoil Data – (AD) 1.2 1 CL 0.8 Aquila Verbitsky BE50 Clark Y Cody RobertsonCR001 0.6 0.4 Drela Dae51 EpplerE387 0.2 Wortmann Fx60100 Martin Hepperlemh32 RG15 0 S 3014 -0.2 -4 -2 0 2 4 6 Angle of Attack [ - deg] 8 10 87 Drag Polar – (AD) 1.4 1.2 1 0.8 0.6 Cl Aquila Verbitsky BE50 Clark Y Cody RobertsonCR001 0.4 EpplerE387 0.2 S 3014 0 -0.2 -0.4 0.01 0.02 0.03 0.04 Cd 0.05 0.06 88 Package Drag and Size Budgets – (AD) Tmax W0 Wstores L / D 0 L / D stores L / D 0 Dstores L / D stores D0 Dp CD (Assuming range is not a limitation when carrier vehicle is operating at maximum thrust ) (Assuming stores affect drag but not lift) m0 T 1 2 ma.c. m p Dp QS K C f (1) (Assuming parasite drag is the only drag on the stores) Equation (1) implicitly relates maximum length to diameter Span is related to length, and chord is related to diameter Remin 60,000 (No airfoil data for Reynolds numbers below 60,000) 89 Package Drag Budget – (AD) Tmax W0 Wstores L / D 0 L / D stores L / D 0 Dstores L / D stores D0 Dstores D0 (Assuming range is not a limitation when carrier vehicle is operating at maximum thrust ) (Assuming stores affect drag but not lift) W0 m0 D0 Wstores mstores Dstores D0 D mstores ma.c. m p m0 D T 1 m m p a .c . Dp D 2 90 Package Size Budget – (AD) CD Dp QS K C f S Dl D 2 2 K f Dl Cf 0.455 2.58 log 10 Re Re (1) (Assuming parasite drag is the only drag on the stores) (Assuming package is a cylinder) (Shevell Fig. 11.4, which assumes Mach 0.5) (Assuming turbulent boundary layer) Vc Equation (1) implicitly relates maximum length to diameter 91 Vehicle Design – (AD) Lift-to-drag ratio for Varying Sweep 19.5 19 V = 10 [m/s] V = 16 [m/s] 18.5 18 L/D 17.5 17 16.5 16 15.5 15 10 20 30 40 Sweep [deg] 50 60 70 92 Tail Design – (AD) SVT CVT bW SW lVT cW SW S C CC lC S HT CHT cW SW lHT SV Tail SVT S HT Historical Data of Vertical and Aft Horizontal Tail Coefficients Aircraft Type CVT CHT Sail Plane 0.02 0.50 Homebuilt 0.04 0.50 Single Engine General Aviation 0.04 0.70 93 Tail Design b Assumption: Length of the aircraft is l Aircraft W cW 2 SW 0.068 0.095 m 2 l Aircraft 0.505 0.575m bW 0.85 0.95 m lVT lHT 0.303 0.345 m cW 0.08 0.1 m 94 Tail Design Tail Areas Tail Area (m2) SVT 0.0067 – 0.0119 S HT 0.0079 – 0.0157 SV Tail 0.0146 – 0.0276 S H Tail 0.0142 – 0.0268 95 Tail Design 10 8 0.1 7 0 L over D Wing z-coordinate 9 -0.1 0.4 6 5 4 0.2 0 3 0.4 -0.2 Wing y-coordinate 0.2 -0.4 0 2 0 2 4 6 alpha (deg) 8 10 Wing x-coordinate 96 Tail Design 10 0.1 8 0 7 L over D Wing z-coordinate 9 -0.1 0.4 6 5 0.2 4 0 3 -0.2 Wing y-coordinate 0.2 -0.4 0 Wing x-coordinate 2 0 2 4 6 alpha (deg) 8 10 97 Tail Design 10 8 0.1 7 0 L over D Wing z-coordinate 9 -0.1 0.4 0.2 6 5 4 0 3 0.4 -0.2 Wing y-coordinate 0.2 -0.4 0 Wing x-coordinate 2 0 2 4 6 alpha (deg) 8 10 98 Tail Design 10 0.1 8 0 7 L over D Wing z-coordinate 9 -0.1 0.4 0.2 0 5 4 -0.2 Wing y-coordinate 6 0.2 -0.4 0 Wing x-coordinate 3 2 0 2 4 6 alpha (deg) 8 10 99 Potential Wing Materials Material u (MPa) (g/cm3) E (GPa) Cost ($/m2) 2024-T3 Al 483 2.78 73.1 55.43 7075-T6 Al 572 2.81 71.7 101.50 Aramid-Epoxy (60% fiber vol.) 1379 1.44 75.8 43.01 S-Fiberglass-Epoxy (60% fiber vol.) 1510 2.05 53.1 34.40 Carbon-Epoxy (60% fiber vol.) 1241 1.55 145 64.54 Blue Foam 0.12 0.021 0.021 16.14 Balsa 25 0.2 4.1 18.70 100 Wing Materials – (ST) Material u (MPa) (g/cm3) E (GPa) 2024-T3 Al 483 2.78 73.1 1 1 7075-T6 Al 572 2.81 71.7 1.17 1.02 Kevlar+Epoxy (unidirectional) 1355-1980 9.06-7.54 44.0-60.0 0.86-1.51 1.66-1.11 S-glass+Epoxy 1355-1980 9.32-7.96 34.7-45.1 0.84-1.43 2.11-1.62 Carbon(HS)+Epoxy 1648-2449 9.13-7.66 81.9-120 1.04-1.84 0.89-0.61 Carbon(HM)+Epoxy 700-932 9.17-7.72 146-222 0.44-0.70 0.50-0.33 Blue Foam 0.12 0.021 0.021 0.03 3481 Balsa 25 0.2 4.1 0.72 17.8 M1 M2 c1 c2 HS = High Strength HM = High Modulus High Strength Carbon Fiber + Epoxy is Best Material 101 Wing Materials Cantilever beam with a uniformly distributed load Maximum deflection occurs at the free end is max w l 4 W l 3 Al 4 g l 4 g 1 8EI 8EI 8EI 8E r 2 r is the radius of gyration W=wl 102 Turn radius & Model – (ST) 103 Spar Deployment Stresses 104 Spar Deployment Stresses 105 Propulsion Power – (PP) Steady Level Flight http://www.teachengineering.com/collection/cub_/lessons/cub_images/cub_air planes_lesson02_fig1.jpg 106 Propulsion – (PP) Motors vs Total Mass 110 100 Total Mass [g] 90 80 8x4 7x3.5 6x4 70 60 50 40 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Motors 107 Matlab vs MotoCalc – (PP) Battery Capacity vs. MotoCalc and Matlab 700 Battery Capacity [mAh] Matlab MotoCalc 600 500 400 Custom CDR Single Hotwind Hacker A20 26M Model Motors 2208/26 Komodo KH220411 108 Propulsion Analysis Software Input D and P Gear Ratio Pout prop= 4.43 W Jeremiah Hall’s Blade Element Code Prop RPM’s η prop Pout motor= Pout prop / η prop Repeat for 30 Selected Motors Output Total Mass Motor Efficiency Function η motor (Motor+Battery) Curve Check Battery Capacity Pout batt= Pin motor / η esc Pin motor= Pout motor / η motor 109 Motor and Battery Mass (PP) Total Mass for Selected Motors 100 Battery Motor Total Mass [g] 80 47.4 38.5 60 42.4 43.9 40 42 20 45 24 23 0 Custom CDR Single Hotwind Hacker A20 26M Model Motors 2208/26 Komodo KH220411 110 Thermodynamic Analysis – (PP) Forced Convection Ploss hA(Ts T ) Assuming: T∞=25 °C Ts=68 °C 111 Electronics Mass and Cost Budget – (EC) Component Mass (g) Cost ($) RC Control Receiver 30 130 Servos 20 25 Flight Dynamics Board 30 500 GPS Antenna 10 30 10-20 20-50 100-110 695-725 Connectors/Wires/Other Total 112 Work Breakdown Schedule –(PP)