1 Trends in UAV Propulsion Liban Emanuel
2 Trends in UAV Propulsion
3 UAV Propulsion Requirements Reliability High power to weight ratio High efficiency in the flight envelope Low emission of IR,Radar and Noise signatures High Electrical Output for the UAV function and payloads Low LCC Complaince to Civil Aviation Regulation
Domain of usage of different propulsion technologies 100 Hybrid Solar Endurance (Hr) 10 1 Hybrid (Battery & Electrical) Electrical (Batteries) Hybrid ( IC& Electrical) Internal Combustion Engines Turbo- Fan 4 0.1 0.1 1 10 100 1000 Payload (Kg)
5 Relative efficiencies of different engines Thermal Efficiency [%] 50 40 30 20 Turbo-Fan Diesel Otto Turbo Jet 10 0 0 20 40 60 80 100 Load [%]
IC Engines Benchmarking Feature LCC Noise MTBF Life Fuel consump tion Power to weight Ratio Weight Instalation Simple Two Stroke (2) ++ ++ ++ ++ + ++++ ++++ (5) ++++ (5) ++++ (5) Four Stroke +++ ++++ +++ +++ +++ ++ ++ +++ ++ Wankel (1) + + + + ++ ++++ +++ +++ ++ Diesel (3) +++ +++ ++++ ++++ ++++ + + ++ + 1. Expensive and unique parts Legend: ++++ The best 2. Simple and cheap 3. Expensive,Exellent SFC &LCC,Heavy 4. Advantage for low HP and Air- Cooling. 6
7 Four Stroke Engine
8 Two (2) stroke engine
9 WANKEL Engine
IC Turbo - charging BMW- Tri Turbo Diesel engine Volkswagen TSI engine 10 VanDyne- Turbo compound
11 Direct Fuel Injection Very-High pressure fuel system
12 Valves control (Semi -Atkinson Cycle) FIAT Multiair Active valve opening control (Atkinson cycle) Adaptation of thermo cycle to loads and power needs. 5-15%Efficiency gain
13 Starter - Alternator Efficient High Power and Moment Built In structure Reliable Enables Hybrid Propulsion
14 Electric Wheel Drive
15 IC UAV Systems Heat Exchangers Scoops Fuel And Oil Systems EFI/ DFI Propellor (Noise & Efficiency) Health Monitoring Systems Transmission Intake system Starter Alternator 1 L.fuel =Kwh Turbo-Charger Exhaust System Shock Mounts
η=56% Thermal efficiency of electrical propulsion G η=0.98% TR 400KV TR 3000V η =0.98% η =0.97% TR 220v η =0.98% TR Charger AC\DC η=0.8% Battery - Battery manufacture Battery Supply & Disposal Weight η=0.95% 16 Total well to wheel efficiency 26 % MotorControls η=0.8% Battery η=0.9% η=0.95%
17 Trends Electrical propulsion Efficient high -torque electrical motors with power to weight ratio of 8+ Increased demand for a/c electrical consumption for payloads. "Intelligent control of power sources and usage High voltage systems Batteries / Fuel cells with power to weigh ratio 300 --- 600 Watts/Kg 3500 3000 2500 2000 1500 1000 500 B-767 A-340 A-380 B-787 Laser Weapons Direct Energy Weapon KW) 0 1970 1980 1990 2000 2010 2020 2030 2040 Entry Into Service
18 Energy Density - Elec. Drive Vs. IC Engine Battery Fuel Tank Electrical Propulsion Battery Energy density 0.2 kwh/kg Controller Eff. = 0.9 Motor eff. = 0.9 Energy Output: 0.2x0.9x0.9 = 0.16 kwh/kg Fuel Energy Density - 12 kwh/kg Efficiency: Otto= 0.3 Efficiency: Diesel= 0.4 Energy output: Otto - 12x0.3 = 3.6 kwh/kg Diesel - 12x0.4 = 4.8 kwh/kg The ratio between Energy density of IC/ Fuel and Elec. Battery/Motor is 20 30 to 1!!
UAV IC / Electrical hybrid Propellor Elecrtical Motor Controller Power Control Data link to\from A\C command Compressed H2 H2 Fuel Cell dry-fuel cartridges Hydrides Generator liquid H 2 I.CEn gine Battery pack /control 19 µ=13%, µ=27%, µ=37%
20 Electrical Propulsion Laser-- Radiated Energy,HF Very low efficiency ( 3.5% ) At starting point Elec. Motors Weight to power ratio 1:8 Hp/Kg Efficiency (0.95) Axial Flux/ Halbach
System Consideration Motor /Propellor optimisation Max. Efficiency @ Design point Optimal Useage and Control of Energy Sources Prop. Battery A El. Motor ECU Energy Control Battery B Efficiency Noise Power Power (Max-Nominal) Efficiency Heat removal Flight / Energy Control Fuel Cell Power Control Residual Energy Routing of energy Sources Energy Consumption optimisation 21
22 Fuel Cells for UAV s Trends Hydrogen storage improvements Onboard Hyrogen generation Use of Methanol Closed loop water system Advantages Higher Energy Density than battery Fuel Tank Concept Shortcomings Complexity Price. Technology not yet mature
23 UAV - Airborne Fuel Cell
24 Fuel Cells Application Technologies PEM Hydrides/PEM Methanol DMFC Propane /SOFC
25 Photovoltaic hybrid propulsion
26 Hybrid Propulsion
27 PV Propulsion High Altitude Application Unlimited Time on station Technology of PV cells and batteries are not yet mature for this application
28 Bio Propulsion Golden Plover UAV Consumption - 70 gr. of Fat = Fuel Flight of 4000 km non- stop 88 hrs / 250,000 Wing Flaps Take-off weight 200 gr Landing weight 130 gr.
29 Future Trends Albatros
Bio - Propulsion We try to understand and learn? Low Reynolds Aerodynamics Airfoils Materials Smart structures 30
31 Summary of trends IC Engines I.C Engines will continue to dominate UAV Propulsion due to the high energy density/content of the HydrocarbonFuel. UAV Engines benefit from the developments in Automotive Industries. More and more UAV S will require Heavy Fuel capability.
32 Summary of trends Electrical Propulsion Break Through in Energy capacity and power to weight ratio of batteries is needed. The portable I.T. devices as well as automotive applications are taking the lead. Usage for small UAV S with limited flight duration. Important achievements in Electrical Motors and Generators.
33 Summary of trends Fuel Cells Promising technology with higher energy density than batteries (600 wh/kg. and up) Bottled high pressure hydrogen with PM are practical solution for small long range UAV S. Cryogene-hydrogen systems can increase range and payload. Other Fuel- Cell systems are complex and require considerable effort to mature and to reach reliability. In next year or two we shall see Automotive Fuel cells on the market and maybe these technologies can be used in UAV propulsion.
Summary of trends -Photovoltaic Propulsion Need further advances in: Lighter structures. Lighter and higher efficiency of P.V cells. Batteries or Fuel- Cells back-up need much higher power density. Flexible wing flight controls. Efficient Low-speed Propellers. 34
35 Summary of trends Hybrid Systems (I.C and Electrical) Important load fluctuations. Big difference between the requirement for duration of High- Power (T.O) and the cruise power. The A/C design and structure dictates distributed electrical propulsion. Automotive Industry is leading.
36 The dream
37 Summary We still have a lot to learn Thank You