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Capability-Based
Electric
Personal Air Vehicles
May 23rd 2007
Electric Aircraft Symposium
Mark D. Moore
NASA Langley Research Center
757.864.2262
[email protected]
Prior Research
Capabilities
Missions
The 100/100 Aircraft
Enabling Technologies
Prior Research
•
Not What Industry Considers All Electric
– The Prospects and Potential of All Electric Aircraft, Cronin, LockheedCalifornia, AIAA-83-2478, 1983.
– Evaluation of All-Electric Secondary Power for Transport Aircraft, McDonnell
Douglas, MDC Report 91K0418, 1992.
•
Really Good Primer for Electric Vehicle Issues
– Vehicular Electric Power Systems – Land, Sea, Air and Space Vehicles,
Emadi, Illinois Institute of Tech, Marcel Dekker, 2004.
•
One of the Best Overall Electric Aircraft Technology Reports
– Electric Power System for High Altitude UAV Technology Survey, Schmidtz,
Paul, NASA Ames, 1997.
Prior Research
•
Fuel Cell Electric
– Investigation of Fuel Cell Power System for Aircraft Electric Propulsion,
Stedman, J.K., Naval Air Warfare Center FCR-12194A, 1992.
– Fuel Cell Powered Electric Propulsion for HALE Aircraft, Bentz, John, Naval
Air Development Center, American Society of Mechanical Engineers Paper
92-GT-404, 1992.
– Fuel Cell Propulsion for All Electric PAV, Kohout, Lisa, NASA TM 2003212354, 2003.
– Fuel Cell Aircraft Applications Presentation, Dunn, Jim, Portable Fuel Cell
Conference, 2002.
– Latest GM Fuel Cell Developments, Bosco, Andrew, GM, 2001.
– Hydrogenics Fuel Cell Specifications.
Prior Research
•
Electric UAVs
– Flight Testing of an Electric Powered Vehicle, Cross, US Naval Research
Laboratory, AIAA Paper 92-4077, 1992
– Performance Characterization of a Lithium-Ion Gel Polymer Battery Power
Supply System for an Unmanned Aerial Vehicle, Reid, Concha, NASA Glenn
Research Center, SAE 2004-01-3166.
– Flight Testing of an Electric Powered Vehicle, Cross, US Naval Research
Laboratory, AIAA Paper 92-4077, 1992
•
Recent Articles and Activities
– Electric Flight – A Design Exploration, Palmer, EAA Sport Aviation, March
2007.
– Electric Airplane (E-Plane), Stough, Paul, NASA Langley, Jan 2007.
– Air Travel Greener By Design, Report of the Technology Sub-group, 2001.
Prior Research
•
Small Aircraft Design Studies with Electric Propulsion
– Electric Propulsion for High Performance Light Aircraft, Galbraith, A.D.,
Continental Group, AIAA 79-1265, 1979.
– Practical Feasibility Assessment of Electric Power Propulsion in Small
Helicopters using Lithium Hydroxide Battery Technology, Kirchen, Hughes
Helicopters, 1981.
– An Analytical Performance Assessment of a Fuel-Cell Powered Small Electric
Airplane, Berton, NASA TM-2003-212393, 2003.
– Emissionless Aircraft: Requirements and Challenges, Arun, Partial
Unpublished Paper, 2003.
Prior Research
•
Electric Sailplanes
– Silent Worldwide Debut, SSA Convention and Airsports Expo, 2003.
– Silent The Light Sailplane with a Glide Ratio Greater than 31, Alisport.
– Silent AE-1 Specifications.
– Silent IN Specifications.
– Silent US Price List, 2003.
– Antares A Self-Starting Silent Super Sailplane, Boermans, L.M.M., Soaring
Magazine, Feb 2001.
– Antares Electric Motorglider, Lange Flugzeugbau, 2005.
– Antares The Electric Motorglider from Lange Flugzeugbau Part 1,2001.
– Antares Fully Equipt
– Sparrowhawk Ultralight Sailplane, Greenwell, Eric, Soaring Magazine, Jan
2001.
– Battery Powered Sailplanes, Gehrmann, OSTIV Congress, 1999.
Prior Research
•
Hydrogen Vehicles
– BMW Hydrogen Vehicle Presentation, Gebler, 2002 Clean Energy Seminar.
– Hydrogen – The Fuel for Future Powertrain Technologies, Braess, BMW
Motor Group, 2002.
– Hydrogen Storage, Niedzwiecki, Alan, Quantum Technologies, Hydrogen
Vision Meeting, 2001.
Prior Research
•
On the Wild Side
– Futures of Civilian Aeronautics Presentation, Bushnell, Dennis, 2007.
– Advanced Energetics for Aeronautical Applications, Alexander, MSE
Technology Applications, NASA CR-212169, 2003.
– Tip Driven Fan Based on SERAPHIM Technology, Marder, Barry, Sandia
National Lab, SAND2002-0029, 2002.
– Electromagnetic Thrust Patent, Campbell, Patent 6,317,310, 2001.
– Electromagnetic Thrust Patent, Patrick, Patent 6,362,718, 2002.
– Why Small Engines, Edkins, General Electric, SAE, CN-51880, 1957.
Prior Research
•
Web Pages
– Batteries
• Lithium Polymer (SAFT, Electrovaya, Apogee, Maintence)
• Lithium Ion (Toshiba, Panasonic, Prismatic Polymer, Cells for Military Applications)
• Lead Acid (TMF)
• Carbon (Isuzu FDK)
• NiMH (Ovonic)
• Zinc/Air (LBL)
– Fuel Cells
– SoLong Solar Electric AC Propulsion UAV
– Solar Cells (Beco Solar, Uni-Solar, United, Full Spectrum)
– Ultra Capacitors (Power Cache)
– Electric Motors (UQM)
Capabilities
•
Major concern in approaching electric propulsion technologies for aircraft
is to insure desired capabilities determine approaches, not a pet
technology area.
– What is the justification for investment over alternative approaches?
– Electric propulsion promotes low emissions, noise, and improved safety,
ease of use, and reliability as desired capabilities, but require a dramatic
increase in cost while decreasing efficiency (for a conventional installation).
– Why should stakeholders invest in this technology for aircraft?
• Private investors
• Small aerospace (AeroVironment, Scaled Composites, Cirrus)
• Mid-size aerospace (Cessna, Raytheon)
• Large aerospace (Boeing, Lockheed, Northrup)
• Government (NASA, DARPA, FAA)
• Non aerospace (Toyota, Honda, GM)
Personal Air Vehicle GOTChA
GOALS
Reduce
Training
Time/Cost
Goal = 5 days
$1000
SOA = 45 day
$10,000
1
Reduce
Avionics
Cost
Goal = $15K/
suite
SOA = $100K/
suite
2
Reduce
Airframe
Cost
Goal = $20/
lbm struc.
SOA = $100/
lbm struc.
3
Reduce
Propulsion
Cost
Goal = $10/ lbf
SLS thrust
SOA = $40/ lbf
SLS thrust 4
Reduce
SFC
Cruise
Goal = .22
lbm/lbf hr
SOA = .28
lbm/lbf hr
5
Reduce
Community
Noise
Goal = 60 dBA
@ TO/Land
SOA = 84 dbA
@ TO/Land
6
OBJECTIVES
Reduce flight
training time
and cost by
90%.
01
Decrease
avionics suite
cost by 85%.
Reduce
airframe cost
by 80%.
03
02
Reduce
cruise sfc
by 20%.
Decrease
propulsion
system cost
by 75%.
04
05
Reduce
community
noise by 24
db at flyover
TO/landing.
06
TECHNICAL
CHALLENGES
Developing,
integrating, flight
architecture and
control systems
that are failsafe
and reliable.
01
Developing and
certifying flight
architecture and
control systems
within cost.
02
Developing and
certifying low
labor assembly
time structures at
modest
production
volumes.
Quality
Assurance
(QA) based
certification
procedures
instead of
Quality
Control. 04
Develop
reduced part
count and lean
design structural
design
concepts.
Adapt mass
produced
QA
products for
aviation
use.while
developing
new
certification
procedure
framework.
03
APPROACHES
Develop
Naturalistic
Flight Control
Deck with
control,
guidance,
sensing,
avoidance,
and airborne
internet.
01
Develop
health
monitoring,
healing, and
recovery for
failsafe user
interfaces and
flight critical
systems..
02
Develop
autonomous
operation
capability
within Digital
Airspace
03
Develop
streamlined
software and
systems
certification
procedures,
processes, and
tools
06
04
Develop
certifiable
simulatorbased training
that facilitates
use of
Naturalistic
Flight Deck. 05
Advanced low
cost fastener
technologies ie
adhesives, laser
and friction stir
welding.
09
07
Validate low
cost mfg
processes,
materials, and
techniques for
major
components.
Achieving
low cost
variable
pitch ducted
prop while
maintaining
efficiency in
acoustically
constrained
system
05
Develop lowcost variable
pitch ducted
propeller
hub and
blades for
low tipspeed,.
10
Reducing
community
and cabin
propulsion
noise sources
(ie high tipspeed prop,
asymmetric
flow, exhaust,
etc) while
meeting
performance
reliability, and
cost.
06
Develop
integrated and
shielded ducted
propeller
system with
active wake
control, and
acoustical
suppression.
Develop
engine
exhaust
systems that
can survive
sustained high
power
operation. 12
11
08
- Page 1 12
SOA = Cirrus SR-22/TCM IO-550N
Personal Air Vehicle GOTChA
GOALS
Increase
L/D
Cruise
Goal = 16
Decrease
Empty Wt
Fraction
Goal = .58
Increase
Propulsion
System T/W
Goal = 4.0
Increase
Clmax
Landing
Goal = 9.0
Reduce / Eliminate
Harmful Exhaust
Emissions
Goal = 0
SOA =11
SOA = .65
SOA = 2.0
SOA = 2.2
SOA = 350 CO2, 80 CO, 10
HC, 3.5 NOx, .2 lead
(grams/mile)
11
8
7
10
9
OBJECTIVES
Increase
Clmax and L/D
by 50% with a
cruise-sized
wing.
07
Reduce
structural
weight
fraction by
15%
Increase
propulsion
system T/W by
100%.
Reduce
subsystem
weight fraction
by 20%
08
09
Reduce
required field
length by 75%.
Reduce HC, CO,
CO2, particulates,
and lead emissions
by 100%
12
11
10
Reduce NOx
emissions by
100%
13
TECHNICAL
CHALLENGES
APPROACHES
Achieving
simple,
effective,
highlift
system for
higher wing
loading for
efficiency
and ride
quality at
low cost and
high
reliability.
Lightweight
minimum
gage
structures
that achieve
low cost.and
assembly.
08
Lightweight
subsystems
that achieve
low cost and
high
reliability.
09
Achieving
high power to
weight
propulsion
system while
maintaining
equivalent
cost and
maintenance.
10
13
Combustion based
processes produce
harmful emissions
as a byproduct.
12
Current noncombustion based
power generation,
distribution,
propulsion, and
energy storage
systems have low
specific power and
energy density.
13
11
07
Develop no
external
moving part
Circulation
Control
highlift
system
(coanda
blowing
over trailing
edge).
Achieve
simple,
effective,
powered-lift
highlift
system with
low speed
gust control
and engineout
robustnes at
low cost.
Lightweight,
low density,
stiff
materials for
minimum
gage
structures.
14
Integrated
multipurpose
structures.
Lightweight,
low cost deicing system
16
Integrated
multipurpose
subsystems.
17
Develop
alternative
propulsion
systems (ie
variable
compression
engines, multigas generator
fan system,
lightweight
diesel, electric
hybrid, etc.).
15
Simple,
effective
powered-lift
systems.
19
Active and
passive gust
alleviation
systems.
20
Develop combustionbased propulsion
systems for use with
alternative
hydrocarbon fuels
(eg. ethanol,
methanol, bio-diesel)
that avoid octane
additives and has
zero net carbon
increase to the
environment.
21
Develop lowemission
combustionbased propulsion
(eg. gas turbine,
internal
combustion)
and energy
storage systems
for use with nonhydrocarbon fuel
(hydrogen).
22
Develop
highlyefficient,
lightweight
hybrid electric
/combustion
propulsion
systems with
compatible
energy
storage
systems.
Develop highlyefficient,
lightweight
electric
propulsion
power
generation, drive
systems, and
energy storage
systems.
24
18
- Page 2 13
SOA = Cirrus SR-22/TCM IO-550N
25
Missions
•
The design mission will assist in determining the desired capability priority.
– What is the vehicle design mission of interest?
• Light Sport Aircraft Recreational Market
– $100 hamburger, flight training, joy flights, sight seeing
• Recreational Market as emergent market for future transportation choice
– Gridlock commuter, fast regional transport
• New aerospace commercialization opportunities in air services
– Community services, homeland security, surveillance, traffic monitoring, communication,
lightweight express mail delivery
•
If advocating a technology development program without respect for
specific future applications, this is a leap of faith.
– Extrapolating that aircraft should follow automotive path of hybrid to full
electric is not sufficient.
– Automobiles have a very different mission that makes hybrid and all electric
propulsion much more attractive than aircraft (lots of idling, large efficiency
losses due to part power operation, auto engine avg duty is ~25% power).
100/100 Aircraft
•
Achieving low emissions and decreasing dependency on oil will be a
topical research area for many years – but this does not necessarily mean
that electric propulsion technologies should be developed.
•
As part of the previous NASA PAV research, a ‘McDonalds Fryer’
environmentally friendly vehicle concept was developed to investigate the
possibility of a unconventional collaborative research partner.
– Goal was 100 mpg vehicle that cruises above 100 mph.
– Started with a Strojnik S-3 (50’ span side by side seating sailplane) to minimize power
required.
– Added GSE high specific output bio-diesel engine.
– Low wingloading was undesirable for handling qualities and efficient cruise was at too
low of a velocity (80 mph). Investigated lower span, higher speed alternatives.
– Needed greater efficiency, investigated Goldschmied propulsor (also in order to
achieve lower noise without ducted prop drag).
– Needed greater static thrust since Goldschmied propulsor has relatively high
discloading and is only effective at thrust = drag (130% hprop)
– Investigated electric auxilliary wingtip propulsor/turbines as a joint method of reducing
span and increasing takeoff/climb low speed thrust.
100/100 Aircraft
• Analysis results looked compelling, especially for Goldschmeid propulsor potential,
however wing oversizing in cruise still limited efficiency/handling qualities.
16
100/100 Aircraft
• Example 100/100 aircraft concepts utilizing GSE engine Goldschmied propulsor,
with forward batteries to balance and wingtip propulsor/turbines for TO/climb.
17
Synergistic Techs
High Specific Output, Efficient Bio-Diesel Engine
(GSE Heavy-Fuel SIETEC Engine with Variable Compression Ratio?)
55 hp / 45 lbs
.5 to .6 sfc
Integral supercharger
Variable compression ratio
Low pressure fuel injection
Multi-heavy fuel capable
Compact footprint
18
Synergistic Techs
Efficient, Low Noise, Low Cost Propulsor
(Internal Goldschmied Propulsor with Fixed Pitch Plastic Fan?)
130% hprop at thrust = drag
Muted trumpet noise effect from fuselage
Single inflow velocity condition
No bird strike issues
Similar BLPP Experiment
19
Synergistic Techs
Electric Wing Tip Auxilliary Propulsor/Turbine
Cruise sized engine
Wingtip mounted electric motor/alternator
Auxiliary low speed thrust for TO/Climb from batteries
(Ps of 1000 ft/min @ 1320 lbs = 40 hp)
Battery recharge during cruise with no engine power
input and no drag penalty
Blades need to be symmetric with full feather capability
for rotation in both directions
20
Synergistic Techs
Low Cost/Maintenance Small Aircraft Highlift System
(Low Pressure Electric Compressor Pulsed Circulation Control System?)
Cirrus SR-22 Drag Polar
FAR Part 23 Limits
0.26
L/Dmax =18
L/Dcruise = 11
Cruise
~ 0.24
21
Synergistic Techs
Ease Of Use - State of the Art
(System Administrator User Friendliness)
Ease Of Use – Haptic Flight Control System
“H”- Metaphor
22
(Mac/Windows User Friendliness)
Conclusions
•
Research justification is for low emission alternative fuel propulsion, not electric
propulsion.
•
Electric propulsion on aircraft must achieve synergistic integration in order to be
considered, otherwise alternative approaches look better (until technology level of
energy storage changes significantly to achieve parity in performance, cost and
efficiency).
•
Technology goals for research/demonstration activity need to be developed and
attached to future desired vehicle missions and desired societal capabilities.
•
While investigating multiple dependent technologies at the same time is failure
prone, a hybrid electric propulsion aircraft may be able to manage this risk.
•
Opportunities exist to publish at future ATIO conference and to establish a working
group in preparation for future government programs.
•
It is likely that primary interest (and funding) will focus on electric propulsion for
small military UAVs, so any effort should indicate applicability to this application.
•
Other government agency funding will be scarce, so leveraging other industry
efforts in this technology area (ala Tesla) is critical, especially in order to achieve
any near term cost practicality.