1. Fuel Cell Electric Aircraft Energy Challenge New Era of Aviation
James Dunn
Advanced Technology Products Worcester, MA
Electric Aircraft Symposium
San Fran – May 2007
Cover Sheet…
Introduction….

2. Fuel cells in Aviation Electric UAV’s – Helios-NASA- Aerovironment
Auxiliary Power – Boeing APU – Madrid +
Electric Airships – HAA – Lockheed Martin
Electric Propulsion - Manned aircraft - E-Plane

3. Aerovironment “HELIOS” UAV Regenerative fuel cell system

4. High Altitude Airship Solar PV and Fuel Cells

5. Fuel Cell Powered Glider
Electric Glider
Fuel Cell Powered Glider

6. Piloted Fuel Cell Aircraft 2-place Electric DynAero

7. Benefits of Electric Aircraft
Increased Reliability – 1 moving part!
Improved Safety
QUIET - only propeller noise
Improved Comfort and Easy Maintenance
No Vibration
Reduced life-cycle costs
NO EMISSIONS !

8. Why Fuel Cells High Efficiency – 2.5 X Gasoline Engines (60% vs. 23%)
Zero Emissions – Only Water Vapor
No odors or fumes
Hydrogen Fuel – Sustainable and Renewable
High Energy Density – WH/kg
2-3 X battery density

9. The Energy Challenge ! Airplane needs 25kW Power @ 100 mph
300 Mi. flight requires 75 kWh of Energy
Energy system Weight for 75kWh:
- Lead Acid Batteries = 3000 kg
- NiMH Batteries = 1500 kg
- LiIon Batteries = kg
Fuel Cell system (+ 3 kg H2) = 165 kg
(Gasoline Equivalent = 100 kg !)

10. The Challenge – Matching the energy density of Gasoline and IC Engines?
Gasoline =13,200 WH/kg
@ 20% effic. Net = 2600 WH/kg
Best LiIon Batts = 200 WH/kg
Still a 13:1 advantage for Gas!!
(H2 = 30,000 WH/kg)
Issues – Weight, Volume, HEAT, (+$$)

11. Hurdles & Issues System Weight – Power Density/Effic.
Support Components – Power & Weight
Hydrogen Storage/Generation System
Heat Transfer methods & HEX System
Safety Issues – FAA + Ongoing
Customer Acceptance
Costly Technology

12. Hydrogen Sources H2 Gas - High Pressure Tank – 5000 psi
Liquid Hydrogen – Cryo issues
Reformed Gasoline – CO, CO2
Methanol/Ethanol – Direct or reformate
Ammonia (dissociated) – high yield
Sodium borohydride – safe, costly
Magnesium Hydride
Other ??

13. NASA Fuel Cell Study Elements:

14. Selected Aircraft for Conversion
AGA Lafayette III
All Carbon Kit - 28’ Wing
We/Wo = .31
80 hp. Rotax 912
< 12 kW to Cruise
Vne of 180+ kts

15. Aircraft Modeling for Hydrogen PEM Fuel Cell Motor Conversion NASA GRC
MCR01 ULM Kit Plane
Airbreathing Systems Analysis Office (NASA GRC)
Systems Analysis Branch (NASA LaRC)

16. MCR01 ULM Fuel Cell Conversion Power Density Technology Sensitivity: PDPMAD = 1.06 kW/kg
MCR01/Rotax 912
> 800 nm Range
800
Advanced Technology
Fuel Cell Stack Power Density: kW/kg
Electric Motor Power Density: kW/kg
PMAD Power Density: kW/kg
Range = 336 nm
2.3
Gross weight constant at 992 lb limit
2.5
2.0
2.3
1.8
2.1
1.7
1.9
PDStack (kW/kg)
PDMotor (kW/kg)
1.7
1.5
1.5
1.3
Applied State-of-the-Art Technology
Fuel Cell Stack Power Density: kW/kg
Electric Motor Power Density: kW/kg
PMAD Power Density: kW/kg
Range = 58 nm
Further performance gains possible only if PMAD weight is reduced!

17. MCR01 ULM Fuel Cell Conversion Power Density Technology Sensitivity: PDPMAD = 2.60 kW/kg
Advanced Technology
Fuel Cell Stack Power Density: kW/kg
Electric Motor Power Density: kW/kg
PMAD Power Density: kW/kg
Range = 644 nm
2.3
2.5
2.3
2.0
2.1
1.8
1.9
1.7
1.7
1.5
PDStack (kW/kg)
1.5
1.3
PDMotor (kW/kg)
Gross weight constant at 992 lb limit
Diminishing returns on range – The heavy compressed hydrogen tank limits further gains.

18. Program Objectives
Demonstrate viability of Fuel Cell powered electric propelled aircraft
Determine the optimum energy source
Analyze performance parameters & range
Design/develop High efficiency H2 PEM fuel cell
Integrate all components into Airframe and Test
Provide educational vehicle for students

19. Basic Schematic of Components

20. Students at Oshkosh

21. Energy Distribution

22. Battery + Fuel Cell System Rqmts.
Max Power - Batteries + Fuel Cell kw
Bus voltage DC
Net Stack power - cont kw
No. of Cells
Efficiency %
Fuel Cell sys. Wt. (w/sgl.H2 tank) 80 kg
Battery + Master Power Xtrol Wt kg
Total Energy System Weight 130 kg

23. Fuel Cell System target weight
Stack (10-18kW) 25 kg
Blower (Compressor)+ duct 5 kg
Misc. BOP, plumbing, sensors 4 kg
HEX System w/Radiators 9 kg
DC-DC Up-convertor 7 kg
Fuel Cell Controller/mon. 5 kg
Dynatech Tank/Reg kg
Mounting + Misc kg
TOTAL fuel Cell System Weight 78 kg

24. New Lynntech Stack Design
Ultrahigh Efficiency
(60%)
LightWeight – Metal (No
Graphite) Bipolar Plates
Ambient Air Ops
No Compressor
No Hydrators

25. 10 kW Fuel Cell Stack DESIGN SPECIFICATIONS 180 cells
300 cm2 active area
Generation 3 endplates
psia
137 V
75 A
50 ˚C
25 kg (hydrated)
400 W/kg 250 mA/cm2)
720 W/kg mA/cm2) 18KW

26. Specific Energy Equivalent Total Fuel Cell System
Sgl. Tank - 78 kg System - 1 kg H2 = 24 kWH
Net Energy Density = 24/78 = 307 WH/kg
Dbl. Tank – 96 kg system – 2 kg H2 = 48 kWH
Net Energy Density = 48/96 = 500 WH/kg

27. Boeing Fuel Cell Glider Activities
System Integration
Hydrogen storage
Liquid to air heat exchanger
Batteries
Hydrogen delivery/regulation
Fuel Cell Stack
Power Conditioner, Regulation, Battery charger
Motor Controller
Motor
Fuel Cell Controller
Electric controlled propeller
Legend
Fuel
Electricity
Liquid Coolant
Control
Prop Control
“Throttle”
Outside Air
System Lay – out Design
Motor and Drive
Fuel Cell Systems
Compressor
Heat exchanger
Pumps
Controller
Battery
Controllers and Converters
H2 System

28. Boeing Activities Electrical Subsystem
Electrical Subsystem Configuration
Power Balance
Power Demand
Motor & Drive
Controllers
Converters
Power Generation
Fuel Cells
Battery
Ground Auxiliary Power

29. Safety and Flight Testing
Major concern on all new Aircraft
Pilot and Airframe issues

30. Safety and Flight Testing (Whoops – wrong button !)

31. Energy System Challenges
Energy Density
Thermal Management
Recharge or Refuel
Integration of Solar PV
Cost
Life
Reliability

32. Technology Evolution Area Today Future (2020)
Motor/Xtrol 2kw/kg kw/kg
Fuel Cell Sys. 2kw/kg 5-6 kw/kg
Fuel/H2 Storage 7% H2 – Wt %
Energy Storage 200 WH/kg WH/kg
Energy Produced 150 kWH kWH
Range Mi mi.

33. Emerging Energy Solutions
Advanced Batteries – Lithium Ion +
High Density UltraCaps – EEStor – Other
NanoStructured Electrodes – WH/kg
High Temp Fuel Cells – Higher power density
Advanced H2 Storage – New mat’ls + tanks
New Energy Gen. Sources - Many

34. Future Technology Options
Airframe Weight reduction
Improved Airframe/Propulsion Efficiency
Energy/Fuel Storage options
Higher Energy Density Storage Techs
New Designs with integrated storage
Improved Solar PV Design - Integration

35. Future Electric PAV ?

36. CarterCopter Hi-Speed Electric GyroCopter