northrop grumman future aircrafts final report
TRANSCRIPT
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1
Program Final Review
21 April 2010
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N+3 Phase I Final Review
Dr. Sam BrunerPrincipal Investigator
Northrop Grumman Corporation
Contract NNC08CA86C
NASA Glenn Research Center21 April 2010
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Outline
• Introduction• Scenario Development
• Requirements Definition
• Design Tools and Processes
• Candidate Configurations and Technologies
• Air Vehicle Design Studies• Technology Maturation Plans
• Summary and Conclusions
• Closed session with NASA partners
3
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N+3 Phase I Final Review:Introduction
Dr. Sam BrunerManager, Advanced Configurations
Northrop Grumman Corporation
Contract NNC08CA86C
NASA Glenn Research Center21 April 2010
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Northrop Grumman Team
• Northrop Grumman – Scott Collins – Program Manager
– Dr. Sam Bruner - Principal Investigator
– Chris Harris - Systems Analysis IPT Lead
– Nicholas Caldwell - Propulsion Integration
– Peter Keding - Technology Modeling and VehicleTrades/Optimization
– Scott Baber - Configuration Design – Luck Pho - Aerodynamic Design and Performance
– Kyle Rahrig – Acoustic Modeling and Analysis
• Rolls-Royce Liberty Works – David Eames
• Sensis – Dave Miller – Traffic Forecasting and Simulation
• Tufts University – Dr. Rich Wlezien - Future Scenario Research and Technology
Maturation Planning Effort
• Spirit Aerosystems
– Dr. Judy Gallman - Advanced Acoustic Inlet Liner5
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Objectives for Past Eighteen Months
• NASA seeks to “stimulate innovation and foster the pursuit of revolutionary conceptual designs for aircraft that could enter into servicein the 2030-35 period”
• In response, Northrop Grumman: – Developed a credible future scenario to establish a context for the proposed
advanced vehicle concept.
– Executed advanced concepts systems study that methodically identified andevaluated integrated aircraft configurations
– Developed an advanced concept whose mission capabilities would enable it to fill abroad, primary need within the future scenario
– Proposed an prioritized suite of enabling technologies and correspondingtechnology development roadmaps required to realize the preferred vehicle
concept by the 2030-35 timeframe
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Northrop Grumman’s preferred concept is revolutionaryin its performance, if not in its appearance
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Scenario Analysis
• Develop a future scenario that describesthe challenges that may be facingcommercial aircraft operators in the 2030-35 and beyond timeframe. – Provide a context within which the proposer’s
advanced vehicle concept(s) may meet amarket need and enter into service.
• Northrop Grumman provides four scenariosthat cover the range of possibilities – King Carbon
– Not In My Backyard
– Bright Bold Tomorrow – Doom and Gloom
• Scenarios used to develop weightingfactors for use in design trade studies
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NIMBYKing Carbon
Bright, BoldTomorrow
Doom andGloom
Individual Scenario Weighting Factors
Combined ScenarioWeighting Factors
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Traffic and Passenger Forecast
• Scenario studies supplemented byrigorous
– Analysis of current traffic movements – Forecasts of future traffic and passenger
demands
• Simulations provide sensitivities to keydesign parameters
• Final design requirements validatedthrough simulation
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Requirements for Conceptual Design
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Scenario Analysis
Traffic andPassengerForecasts
Solid TRL 6 by 2025 to manage commercial risk
Noise (Cum below Stage 4) -71 EPNdB
LTO NOx Emmissions (below CAEP/6) -75%
Performance: Aircraft Fuel Burn better than
70%
Performance: Field Length Exploit
Metroplex
Concepts
Range 1600nmPassengers 120
Field Length, TO and Ldg (SL, Std Day) 5,000 feet
Cruise Mach 0.75
Cruise Altitude < FL450
N+3 (2030-2035Service Entry)
Advanced Aircraft
Concepts Goals
(Relative to User-
Defined Reference)
Mission
Requirements
Derived from Traffic
Study
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Reference Vehicle vs Preferred Vehicle
• Reference Vehicle – Vehicle used as baseline for establishing current-year capability
– Perturbation on a 737-500, assuming constant technology
– Resized to meet same mission requirements as the preferred vehicle
– “Rubber Engine”, “photographically scaled” wing
• Preferred vehicle – Final design concept that meets the mission requirements and best meets the N+3objectives
– Embodies prioritized set of enabling technologies
– Chosen via a rational downselect from a wide choice of architectures
– Only indirect consideration of cost
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Preferred Vehicle Overview
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Technology F E N L
N + 3 P h a s e 1 T e c h n o l o g i e s
Three-Shaft Turbofan Engine
* Ultrahigh Bypass Ratio of ~18* Compressor Intercooling* Lean-Burn Ceramic Matrix Composite
(CMC) Combustor
* CMC Turbine Blades
* Coo led Cooling Air Turbine* Shape Memory Allo y Nozzle
* Porous Ceramic Nozzle Material* End othermic Fuel System
Ultrah igh-Performance FiberAdvanced Metallics
Aeroservoelastic StructuresSwept-Wing Laminar FlowLarge Integrated Structures
Landing Gear FairingsPi Preform Joints
Carbon Nanotube Electrical CablesAdvanced Inlet Acoustic Liner
F=Fuel Burn, E=Emissions, N=Noise, L=Field Length
Large BenefitSmall BenefitNo Benefit
111.0
33.3
Dimensions in ft
98.7
12.5
26˚
Range (With Reserves): 1,600 nm
Passengers: 120
Field Length Capability: 5,000 ft
Cruise Altitude: 45,000 ft
Design Mach Number: 0.75
Ramp Gross Weight: 80478 lb
Zero Fuel Weight: 71,333 lb
Operating Empty Weight: 46,133 lb
Empty Weight: 43,666 lb
Wing Aspect Ratio: 12.7
Cruise Specific Fuel Consumption: 0.451 pph/lb
Phase 1 Preferred Configuration Summary
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Summary Accomplishments
• Northrop Grumman meets all design intents. – All goals met except fuel burn
– Fuel burn still represents outstanding improvement
– Achievable with technology possible by 2025
12
Noise (Cum below Stage 4) -71 EPNdB -70 EPNdB LTO NOx Emmissions (below CAEP/6) -75% -75%
Performance: Aircraft Fuel Burn better than
70%
64%
Performance: Field Length Exploit
Metroplex
Concepts
Exploit
Metroplex
Concepts
Range 1600nm 1600nm
Passengers 120 120
Field Length, TO and Ldg (SL, Std Day) 5,000 feet 5,000 feet
Cruise Mach 0.75 0.75
Cruise Altitude < FL450 < FL450
N+3 (2030-2035
Service Entry)
Advanced Aircraft
Concepts Goals
(Relative to User-
Defined Reference)
Mission
Requirements
Derived from Traffic
Study
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Technology Maturation Plans
• Seventeen high priority technologies identified
• Appendix to written report discusses disposition of 72technologies considered but dismissed
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Today’s Objectives
• Describe the Northrop Grummanexperience in detail
• Demonstrate:
– Our approach meets the broad needs forthe years 2030-2035
– Our design achieves the environmentalintent of the NASA N+3 challenges
– We have identified the technologies thatenable revolutionary improvements invehicle performance
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Subsection 6.1
Trade Studies
Subsection 5.3
Technology Assessment
Subsection 5.2
Preliminary Concepts
Section 6
Analysis
Subsection 6.4
Exit Criteria
Section 7 Technology Risk
Phase 2
Technology
Roadmaps, Findings
and Recommendations
Phase 2 Proposal and
Final Report
Subsection 3.11 &6.5
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Outline
• Introduction• Scenario Development
• Requirements Definition
• Design Tools and Processes
• Candidate Configurations and Technologies
• Air Vehicle Design Studies• Technology Maturation Plans
• Summary and Conclusions
• Closed session with NASA partners
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N+3 Phase I Final Review:Scenario Study
Dr. Rich WlezienTufts University
Contract NNC08CA86C
NASA Glenn Research Center21 April 2010
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N+3 Scenario Objective
Scenario Task Objective: develop a future
scenario within which to describe thechallenges that may be facing commercial
aircraft operators in the 2030-35 and beyond
timeframe
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Scenario Process
• NASA guidance – scenario may be developed using relevant existing
studies or as a part of this study
• Team conducted research on existing studies, literature search on issues,
and held interchange meetings
• Observed three primary scenarios across research findings
• Developed weighting factors to discern value with respect to goals of
concepts and technologies in context of scenarios
• Identify those that provide greatest value across scenarios
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Future Energy Scenarios
Collapse
E n e r g y a n d R e s o u r c e U
s e
Today
Reducing Demand
Balancing Resources
Increasing Supply
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Global “growth” scenario (Increasing Supply)ExxonMobil projects that global oil production will continue to grow well beyond 100 million barrels a day. In its latest reference scenario, for example, the US Department of Energy (Energy Information Administration), expects global production to be 112 million barrels a day in 2030.
Global “plateau” scenario (Balancing Resources)Shell “Blueprints Scenario”, argues that global production will flatten around 2015 and remain on a
plateau into the 2020s propped up by expanding volumes of unconventional oil production because of the decline of conventional oil production.
Global “descent” scenario (Reducing Demand)Shell “Scramble Scenario” predicts a fall off of global production as oilfield flows from the newer
projects fail to replace capacity declines from depletion in older existing fields.
Global “collapse” scenarioThere is another, very worrying, scenario, wherein the steady fall of the descent scenario is steepened appreciably by a serial collapse of production in some - possibly many – of the aged supergiant and giant fields that provide so much global production today.
The Industry Taskforce on Peak Oil and Energy Security ( Arup, FirstGroup, Foster and Partners, Scottish and Southern Energy,
Solarcentury, Stagecoach Group, Virgin Group, Yahoo!) considers that the “descent” scenario is a highly probable global
outcome, but they also fear that a “collapse” scenario is possible, albeit less likely.
Energy Scenarios and Advocates
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Aircraft Efficiency Data
NLR-CR-2005-669Fuel efficiency of commercial aircraft, An overview of historical and future trends
Peeters P.M., Middel J., Hoolhorst A.
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Sources: 15 scenarios from 4 studies
• World Business Council for Sustainable Development,Global Scenarios 2000-2050 (WBCSD – 3 scenarios)
• Shell Energy Scenarios to 2050 (Shell – 2 scenarios)
• JPDO Futures Working Group (JPDO – 5 scenarios)• Maintaining U.S. Leadership in Aeronautics: Scenario-
Based Strategic Planning for NASA's AeronauticsEnterprise, National Research Council (NRC – 5scenarios)
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Scenario Overview
NIMBYKing Carbon
Bright, BoldTomorrow
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Doom andGloom
D-1 C-1 B-5 A-1 D-2 C-3 B-3 A-2
C-2 A-3 B-1 A-3 A-5 B-2B-4
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Scenarios breakdown
Organization Report/Scenario Title
A) JPDO Futures Working Group “Futures Working Group Final Report (Draft)”, 20041. Is it hot in here or what?
2. Storm Clouds
3. Markets Rule
4. Asia’s Century
5. Terror Uncontained
B) National Research Council (NRC) “Maintaining U.S. Leadership in Aeronautics: Scenario-
Based Strategic Planning for NASA's Aeronautics
Enterprise”, 1997
1. Pushing the Envelope
2. Grounded
3. Regional Tensions
4. Trading Places
5. Environmentally Challenged
C) World Business Council for
Sustainable Development (WBCSD)
“Exploring Sustainable Development”, 1997
1. FROG! First Raise Our Growth
2. Jazz – Dynamic Reciprocity
3. GEOpolity – Sustainable Guidance to Market
D) Shell “Shell Energy Scenarios to 2050”, 2008
1. Scramble!
2. Blueprints
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Reducing Demand“King Carbon”
The confluence of peak oil and globalwarming concerns results in the imposition ofstrict “carbon taxes” to limit the burning of
fossil fuels. Years of complacency and abusiness as usual approach has led to therealization that something must be done
quickly. Insufficient investment in alternativefuels and sequestration technologies leaveslittle time to invest in alternative fuelinfrastructure. Ground transport andelectricity generation at least have somealternatives – air transport must address
skyrocketing fuel costs with new approachesto conservation and efficiency. Globalalliances cutting across the developed andundeveloped countries set global standardsfor carbon consumption.
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Global Oil vs. Projected Demand
M B P D
( m i l l i o
n b a r r e l s p e r d a y )
100
80
20
40
0
60
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Balancing Resources“Not in My Back Yard”
A combination of new energy sources andnew approaches to energy conservation havebrought supply and demand into a long-termbalance. Air transportation is growing slowly,but remains a strong component of the overalltransportation mix. The push to greater
efficiency and energy conservation hasreinvigorated the cities, leading to muchhigher population densities. Land for airportsis at a premium, and the luxury of large bufferzones is not viable. Local populations arebecoming increasingly intolerant to noise and
airport emissions such as NOx, soot,particulates, and hydrocarbon emissions.Strict local rules evolve first in the EU andCalifornia, and the bar for noise and localemissions is set very high.
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Shell “Blueprints” Energy Projection
100
200
0
300
400
M B P D
O E
( m i l l i o n b a r r e l s p e r
d a y
o i l e q u i v a l e n t )
500
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Increasing Supply“Bright, Bold Tomorrow
New approaches to energy initiated in theearly 21st century now pervade thetransportation system, and reasonably-pricedcarbon-based biofuels from algae farms arenow widely available. The world economyhas more than recovered from the downturn
of the first decade, and renewed prosperityplaces high demand on global travel. Newinvestment in airport infrastructure hassaturated the hub-and-spoke system, andwidespread point-to-point transportation isnow available. Smaller, single-pilot aircraft
dominate the transportation system, and theonly realistic alternative is smaller localairports, and closer spacing for aircraft goinginto the larger airports.
E on P ojection of Fossil F el
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Focus on sequestration for global warming amelioration
Exxon Projection of Fossil FuelGrowth
M B P D
O E
( m i l l i o n b a r r e l s p e r
d a y
o i l e q u i v a l e n t )
Th S i th t C th
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Bright, BoldTomorrow
King Carbon
NIMBY
Three Scenarios that Cover theSpectrum of Future States
Noise
LTO Emissions
Fuel Burn
Field Length
Goal Scenario
Local
Global
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Summary
Scenario Challenges
• NIMBY foresees modest (2%/yr) world-wide growth in air transport• U.S. and Europe call for stricter emission and noise requirements similar to N+3 goals
• Replacement of aircraft, in particular single-aisle class will occur
• Aircraft must offer improved efficiency and greater locale (local emissions requirements may vary
between airports) and passenger acceptance to enable market growth
• NextGen, through ops improvements, will enable smaller aircraft and better local acceptance
• King Carbon foresees decreasing (-2%) demand for air transport due to increasingly higher cost of fuel
and shortages from lack of national planning• Taxes instituted to support entire transportation sector fuel efficiency initiatives
• Alternative forms of moderate range transportation take hold
• Slower growth in developing countries and retraction in U.S. and Europe
• Fleet recapitalization will slow unless national technology investments reduce acquisition costs
• Development of efficient aircraft w/equally attractive cost and time to market is critical
• Systems capable of performing on different fuels depending on availability in areas of operation
• Bright, Bold Tomorrow occurs under strong national and global economies with correspondingly robust(4%) increase in air transportation
• Multi-national investment strategies occur as countries partner to develop techs and systems
• Economic expansion results in need and opportunity for timely travel to a wide range of locales
• Effective management of air travel industry growth to prevent emission issues occurring beyond whattechnology can resolve will be critical
• Technical challenges will include bringing fleets of safe, cruise efficient STOL aircraft online and thecorresponding management of increasingly complex airspace
NIMBY
King Carbon
Bright, BoldTomorrow
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Mapping Goals to Scenarios
Application of Weighting Factor discussed in Analysis Process
Individual Scenario Weighting Factors
Combined ScenarioWeighting Factors
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Summary
• Future likely dominated by national strategies andobjectives in energy, environment, economy, anddefense
• Team presented summary of existing studies,literature search on issues, and internal observations
• Identified three primary scenarios covering researchfindings
• Used weighting factors to discern value of concepts
and technologies in context of scenarios and relatedto goals
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Outline
• Introduction• Scenario Development
• Requirements Definition
• Design Tools and Processes
• Candidate Configurations and Technologies
• Air Vehicle Design Studies• Technology Maturation Plans
• Summary and Conclusions
• Closed session with NASA partners
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N+3 Phase I Final Review:Requirements Definition
Dave MillerSensis Corporation
Chris Harris
Northrop Grumman Corporation
Contract NNC08CA86C
NASA Glenn Research Center21 April 2010
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Agenda
• Simulation and Modeling Process
• N+3 Impact Assessment Approach
• Airspace Concept Evaluation System (ACES)
• Future Demand Generation
• NextGen Assumptions for N+3 Simulations
• Summary of Assumptions of N+3
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Simulation and Modeling Process
• System-wide simulations using the Airspace Concept Evaluation System (ACES)
• AvDemand was used to create future schedules with N+3 vehicle
• Tail-tracking algorithm was used to create airframe-based itineraries
• Simplified N+3 performance model used in ACES 4-D trajectory simulator
• Airport and airspace capacities reflect JPDO-provided NextGen assumptions
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N+3N+3
N+3
N+3
Primary goal was NAS assessment of passenger throughput and delay
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N+3 Impact Assessment Approach
• A surrogate vehicle was used for the initial analysis of N+3 vehicleperformance to develop sensitivities for requirements
• Targeted markets consisted of origination and destination (O/D) pairsserviced by the Boeing 737 and other similar aircraft
• Separate future schedules were created and simulated for the reference
vehicle, similar vehicles, and the advanced N+3 vehicle and the resultscompared
– Differences were used to assess the impact of the advanced vehicle configurationson NextGen
– Performance metrics investigated included fuel efficiency, thrust, cruise speed, and
cruise altitude – System-wide comparisons included passenger throughput and delay
• Assessed N+3 field length by using a bypass alternative that shiftsdemand to regional, underutilized facilities
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Airspace Concept Evaluation System
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Airspace Concept Evaluation System(ACES)
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• Distributed, fast-time, computer simulation of gate-to-gate flightoperations in the NAS
• Developed in support of the NASA Virtual Airspace Modeling andSimulation (VAMS) project to assess future Air Traffic Management (ATM)concepts
• Utilizes an agent-based software architecture to model the behavior andinteractions of Traffic Flow Management (TFM), Air Traffic Control (ATC),Flight Deck, and Airline Operational Control (AOC) entities
• Models terminal, and en route operations
• Utilizes a high fidelity, physics-based, four-degrees of freedom trajectory
generator• Used to assess new vehicle concepts in current and future air traffic
environments
f h
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ACES Software Architecture
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Flight Data Set
Departure Time
Airport Capacities
Airport States
VFRVFR
VFRIFR
VFR
Cruise Alt & Speed
Trajectory
Aircraft Type
Origin/Destination
RUCWinds
Static Data
Airport AdaptationData
Center/SectorAdaptation Data
Sector Capacities
ACES Inputs
Center BCenter A
Airport
4 0 n m
TRACON
Airport
4 0 n m
TRACON
ACES Simulation
TFM
TFMTFM
TFM
TFM
ATC
ATC
ATCATC
ATC
ATC
Delay Maneuvers
ACES
Functionality
Departure Meter FixSeparation
Airline OperationsControl
Rerouting
Surface Traffic
LimitationsConflict Detection &
Resoluation
Generic/EnhancedAirport Model
Winds On/Off
Aircraft StateMessage
Center HandoffMessage
Flight Time DataMessage
Airport AcceptanceRate Message
Local Data Collection
ACES Outputs
d G
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Future Demand Generation
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• AvDemand was used to create future demand schedules from a
representative “seed” day
– Seed day was Thursday, July 13th 2006
– Same seed day used by JPDO for NextGen research
• N+3 vehicle was substituted into future demand schedules
– Assumed a production rate of 400/year for N+3 vehicle with production starting in
2030 and 4000 vehicles in service by 2040
– Took into account present day fleet mix and aircraft types
– Assumed retirement of present-day aircraft types e.g. MD-80, DC-9, B737, etc.
Ai f b d I i i
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Airframes-based Itineraries
43
• A tail-tracking algorithm was used to
link together the flights in the
AvDemand generated future schedules
– Required to honor turnaround times and
account for propagated delay
– Propagated delay accounts for 30% of
all delay according to the Bureau of
Transportation and Statistics
• Future schedules generated had a
median of 5 flights per day per
airframe
NextGen Assumptions for N+3
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NextGen Assumptions for N+3Simulation
44
• NextGen to be fully implemented by 2025
• Modeled NextGen improvements:
– All known new and planned runway construction and JPDO operational
improvements – Airport capacities were increased on average for the top 35 airports by
approximately 45%
– En route sector capacities were increased by a factor of 1.7
• Monitor Alert Parameter (MAP) is used to determine sector capacity
• MAP values were multiplied by the improvement factor to increase the
sector capacity for the N+3 simulations
How Flights Were Shifted for
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How Flights Were Shifted forMetroplex Operations
45
• Traffic was offloaded to auxiliary
airports within 70 nm of hub
airport to ensure that
capacity/demand ratio was less
than 90% at hub
• Assumes JPDO NextGen airport
capacities for 2025
Summary of Assumptions for N+3
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Summary of Assumptions for N+3NAS Simulations
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• NextGen implementation by 2025
– En route sector capacity increases due to operational improvements
– Airport capacity due to new runway construction and operational improvements
– Availability of Virtual Towers for regional airports to enhance Metroplex operations
• Production rate of 400/year for 10 years starting in 2030
• Turnaround time of 36 min
• Metroplex defined by 70 nmi radius from hub airport, 40 flights/hour
capacity each satellite airport
R i t D fi iti P
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Requirements Definition Process
47
ACES N+3 NASSimulations
ScenarioInputs:
1.8X – 3.0XTraffic Levels
NextGen Assumptions
Bright, BoldTomorrow
King Carbon
NIMBYOVERALL
N+3
Surrogate
N+3
PreferredConfiguration
li
r r i
ir r i i
ir r
Ir i l
r r
ir r
ri i i i
i
i
ir r i
r ri
r i i
Center BCenter A
Airport
4 0 n m
TRACON
Airport
4 0 n m
TRACON
ACES Simulation
TFM
TFMTFM
TFM
TFM
ATC
ATC
ATCATC
ATC
ATC
l r
r r r ir i
irli r i
r l
r i
r r iLi i i
li il i
riir r l
i
ir rr li iir r
L l ll i
ITERATIVE
Metroplex(Field Length)
Cruise Speed
Range
Passenger Load
Primary Mission is to Serve Traffic
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Primary Mission is to Serve Traffic Volumes Predicted by BBT Scenario
48
Enplanements(1000’s)
High traffic growth rates for an extended period can be
sustained if infrastructure & macroeconomics are supporting.
TRAFFIC GROWTH
PREDICTIONS:
Scenario %/yr 2035
NIMBY 2% 1.6x
KC -2% 0.6xBBT 4% 2.7x
Oil
Embargo
Is Met ople Needed?
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Is Metroplex Needed?
49
• Sensitivity to evensmall increases intraffic levels, wellbelow predicted 1.8X-3X range is high
• NextGen and currentinfrastructure aloneare not enough for
even moderate trafficincreases
+ NextGen
Metroplex Resources are Required to Enable the Challenging Future Traffic Levels
1.1X 1.5X
Metroplex Airfields are Available to
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Metroplex Airfields are Available to Add Large Infrastructure Set to NAS
50
35 Major Airports
Goal is to leverage existing Metroplex runways to exploit underutilized
resources.
Population Distribution NextGen Enabled Fields
Identification of Metroplex Assets
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Identification of Metroplex Assets
51
• Metroplex offloading was used to assess the N+3 field length capability
– Support traffic projections by shifting flights to nearby underutilized runways
– Utilization of existing Metroplex assets was assumed (no new construction)
• Selection of Metroplex Airports
– Located within 70nm of the associated primary airport
– Public-use airport
– At least 150ft width
– History of commercial service
Metroplex Infrastructure By Runway
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52
p y yLength Shows Largest Gain at 5kft
Creating a scheme to offload traffic from major hubs, utilizing NextGen-
enabled airfields, is a crucial component of the 2035 simulations…
Determining field length capability depends greatly upon NextGen
resources in ~2035, combined with future traffic projections.
>=5k 4k<=5k 3k<=4k
Maximum Runway Length (ft)
# Runways
Employing Metroplex Infrastructure
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p y g pReduced Critical Airport Capacities
53
674% 673%
637%
493%
329%
186%
118%
75%52%
37%23% 15% 6% 2% 1% 0%
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Length of Longest Runway (Thousands of Feet)
Using metroplexairports with 5000’
or longer runways…
Reduces significant levels of hub traffic volume…
By offloading to metroplex fieldsat critical capacity ratio.
1
23
Critical ~3X traffic levels were successfully met. High delay
levels were still observed.
F l i g h t C o u n t s
Time of Day
% I n
c r e a s e i n A i r p
o r t s R e l a t i v e t o
C u r r e n t T o w e r e d A
i r p o r t s
What is the Right Cruise Speed?
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-
200
400
600
800
1,000
1,200
1,400
1,600
1,800
- 2 1
- 1 8
- 1 5
- 1 2 - 9 - 6 - 3 0 3 6 9
1 2
1 5
1 8
2 1
2 4
2 7
3 0
3 3
3 6
3 9
4 2
4 5
4 8
5 1
5 4
5 7
6 0
F l i g h t C o u n t s
Statistics (minutes)
What is the Right Cruise Speed?
54
0
1000
2000
3000
4000
5000
6000
228 248 268 288 308 328 348 368 388 408 428 448 468 488 508
F l i g h t C o u n t s
Knots
Flight Data Set Cruise Speed Distribution
CESTOL
B737
N+3737
To minimize adverse impact on NAS traffic delay and throughput, a
minimum cruise speed of Mach 0.75 was adopted.
Cruise Speed (knots)
12 knots reduction leads to 9minute average delay increase
9 min(mean)
N+3
N u m b e r o f F l i g h t s
More airframes are requiredsince flights/day decreases.
Arrival Delay Difference (min)
Passenger & Range Requirements
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Passenger & Range Requirements
• The current most prevalent vehicle size class in use in terms of number
of flights is also aptly suited to the metroplex mission:
55
max (nm)
median
75th percentile
25th percentile
min
Number of
flights
800600
1600
2400
Top 20 airframes show mainly 120-150 PAX
aircraft cruising <1600nm almost exclusively
Further Refining the Range
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56
g gRequirement
• The range requirement was determined from projected 2025 levels from
FAA estimated city-pair growth rates, using a Pareto type approach…
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Stage Length (distance between city pairs), nm
Current & Future Stage Length Distributions Cumulative Projection 20252400 nm
1600 nm
800 nm
600 nm
To best meet the broadest possible need for future metroplex
missions, a “conservative” 1600 nm range was selected.
Stage Length (nm) Stage Length (nm)
Distributions show low
sensitivity of overallcharacter to growthlevels. Pareto
Zone
N u m b e r o f F l i g h t s
Best Passenger Count for 1600nm
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gMetroplex Operations Mission
• Correlation with the top
20 most often flownairframes show that 120-150 PAX is primary need
• Metroplex operations willlikely be more readily
accepted with smaller,lighter, cleaner, andquieter aircraft
• Smaller aircraft assurehigher loading rates, andreduce propagatedsystem delays
57
The primary vehicle need in the future NAS is the 120-150 PAX
class. 120 was chosen for best Metroplex adoption potential.
Summary of Derived N+3
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yRequirements
• NextGen alone is not sufficient
• By engaging Metroplex fields with 5000’ runways (or greater), a huge
addition in capacity and attendant reduction in delay is achieved
• Substantial future delays will be seen (or attendant price increases,
congestion, frustration) if not implemented soon
• For the broadest capability, a range of 1600 nm is sufficient
• Passenger count of 120 will serve primary Metroplex mission
• Cruising at Mach 0.75 or greater will best utilize N+3 airframes
58
Mission Requirements
Range (with reserves): 1600 nm
Passengers: 120
Balanced Field Length (Sea Level/Standard Day): 5000 ft
Landing Distance (Sea Level/Standard Day): 5000 ft
Minimum Cruise Mach: 0.75
Outline
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Outline
• Introduction• Scenario Development
• Requirements Definition
• Design Tools and Processes
• Candidate Configurations and Technologies
• Air Vehicle Design Studies• Technology Maturation Plans
• Summary and Conclusions
• Closed session with NASA partners
59
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60
N+3 Phase I Final Review:Design Tools and Processes
Peter KedingConfiguration Design and Integration
Northrop Grumman Corporation
Contract NNC08CA86C
NASA Glenn Research Center21 April 2010
Tools and Processes Overview
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61
Tools and Processes Overview
Tools
• Flight Optimization System (FLOPS)
• Airspace Concepts Evaluation System (ACES)
• Conceptual Mass Properties (CONMAP)
• Model for Investigating the Detectability of Acoustic Signatures (MIDAS)
Processes• Calibration
• Optimization
• SystemEffectiveness
Ratings (SER)
Subsection 6.1
Trade Studies
Subsection 5.3
Technology Assessment
Subsection 5.2
Preliminary Concepts
Section 6
Analysis
Subsection 6.4
Exit Criteria
Section 7 Technology Risk
Phase 2
Technology
Roadmaps, Findings
and Recommendations
Phase 2 Proposal and
Final Report
Subsection 3.11 &6.5
Vehicle Design Tools
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Vehicle Design Tools
62
FLOPS• Developed by NASA Langley
• Used for preliminary design and analysis of flight vehicles
• Uses nine separate modules that allow formultidisciplinary vehicle design, including:
• Weights
• Aerodynamics
• Takeoff/landing
• Engine data scaling and interpolation
• Mission performance
• Program control
CONMAP• Developed by Northrop Grumman
• Provides high-level weight and longitudinalcenter of gravity estimates based on vehiclegeometry, system definitions, and vehiclefunctions
CONMAP FLOPS
W ei ght ( lb) W ei ght ( lb) [ lbs] [ %]
Structure 51433.8 51743 309.2 0.60%
Wing 19230.6 19391 160.4 0.83%
Horizontal Tail 1411.2 1408 -3.2 -0.23%
Vertical Tail 1490.5 1487 -3.5 -0.23%
Fuselage 18055.2 18135 79.8 0.44%
A li gh ti ng & A rr es ti ng G ea r 7 28 9. 4 7 36 4 7 4. 6 1 .0 2%
E ngi ne Sec ti on & N acel le 3 95 6. 9 3 95 8 1 .1 0 .0 3%
Miscellaneous 0.0
Propulsion 13259.1 13259.0 -0.1 0.00%
E ngi ne I ns ta lla ti on 1 04 68 .0 1 12 46 -0 .1 0 .0 0%
Afterburner 0.0
Exhaust System 0.0
A cc es sory G ea rbox es /D ri ve s 5 62 .7
Engine Controls 79.3
Starting System 136.0
Fuel System 1029.1 1029 -0.1 -0.01%
M is ce ll aneous ( Thrust R ever se r) 9 83 .9 9 84 0 .1 0 .0 1%
Systems & Equipment 23883.0 24090.0 207.0 0.87%
Flight Controls 3421.3 3445 23.7 0.69%
Auxiliary Power Plant 934.0 933 -1.0 -0.11%
Instruments 656.6 660 3.4 0.52%
Hy dra ul ic s & Pn eu ma ti cs 1 41 8. 4 1 42 8 9. 6 0 .6 8%
Electrical System 2378.2 2400 21.8 0.92%
Avionics 1620.0 1634 14.0 0.86%
F ur ni sh in gs & E qu ip me nt 1 23 43 .9 1 24 91 1 47 .1 1 .1 9%
A ir Condi ti on ing & A nt i- Ic ing 1 01 0.7 9 99 - 11 .7 - 1.15 %
Load & Handling 100.0 100 0.0 0.00%
Weight Empty 88575.9 89092.0 516.1 0.58%
C rew a nd Bag ga ge - F li gh t 4 20 .0 4 20 0 .0 0 .0 0%
C rew a nd Bag ga ge - C abi n 1 05 0. 0 1 05 0 0 .0 0 .0 0%
Engine Oil 120.0 120 0.0 0.00%
Fuel, Unusable 138.0 138 0.0 0.00%
Passenger Service 1031.9 1040 8.1 0.78%
Clean Operational Weight 91335.8 91860.0 524.2 0.57%
Cargo - Containers 0.0 0
E xt ern al Fu el T an ks & P rov isi on s 0 .0 0
Miscellaneous 0.0 0
Operational Weight 91335.8 91860.0 524.2 0.57%
Passengers 27540.0 27540 0.0 0.00%
Passenger Baggage 6480.0 6480 0.0 0.00%
Car go - Conta iner s ( Ba gg ag e onl y) 1 29 6.0 1 30 7 1 1 .0 0 .8 5%
Car go ( Chos en to match TOG W) 1 54 8.0 1 54 8 0 .0 0 .0 0%
F uel , U sa bl e - I nt er na l 4 60 00 .0 4 59 17 - 83 .0 - 0. 18 %
Takeoff Gross Weight 1 74 19 9. 8 1 74 652 .0 452.2 0.26%
Delta
Additional Tools
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MIDAS• Developed by Northrop Grumman
• Allows for calculation of noise sources• Some modules based on NASA’s ANOPP
• Includes models to predict shielding andrefraction, acoustic radiation and ductpropagation, and acoustic attenuation andreflection
• Flight profile and individual noise sourcesused to compute EPNL
Additional Tools
63
ACES• Simulates nationwide air traffic
management, flight, and airspaceoperations center functions
• Allows system-wide impacts of new aviationconcepts to be analyzed
• Visualization of how the NAS will handlefuture flight demands
FLOPS Calibration Process
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FLOPS Calibration Process
• Tool calibration andvalidation requiredbefore beginning designprocess
• B737-800 with the
CFM56-7B27 used tocalibrate FLOPS
• Used publically releasedgeometry to generatevehicle in CATIA andFLOPS
• Must calibrate weightsbefore aerodynamics
64
FLOPS737-800
CATIA File
FLOPS SinglePoint Analysis
737-800CONMAP File
Initial 7 37-800FLOPS File
737-800FLOPS File
Weights Calibration & Validation
CATIA 3-DMODELCONMAP
Aerodynamics Calibration
FLOPS MultiPoint Analysis
737-800FLOPS File
Publicly Release dPerformance Information
1
2
3
Aerodynamics Validation
AerodynamicValidation
PerformanceComparison
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
18.00
20.00
0 .0 0 0 .1 0 0 .2 0 0 .3 0 0 .4 0 0 .5 0 0 .6 0 0 .7 0 0 .8 0 0 .9 0 1 .0 0
Mach
L / D
o r M *
M a x L / D
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 . 00 0 0 0 . 02 0 0 0 . 04 0 0 0 . 06 0 0 0 . 08 0 0
CD
C L
Historical
Aerodynamic Trends
Weight StatementComparison
737-800FLOPS File
Final 737-800FLOPS File
Publicly Released B737 -800Weight Information
IF FLOPS = CONMAP
IF FLOPS = PUBLIC
FLOPS Weight Calibration
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FLOPS Weight Calibration
• 737-800 CATIA model used to
generate weight statement inCONMAP, geometric inputused to create FLOPS weightstatement
• Publically released weightinformation used to validateCONMAP
• FLOPS/CONMAP weightcomparison used for FLOPS
calibration, reconcileddifferences in FLOPS usingcalibration factors
• Iterated until weights werewithin an acceptable tolerance
65
FLOPS737-800
CATIAFile
FLOPS SinglePointAnalysis
737-800CONMAP File
Initial737-800FLOPS File
737-800FLOPS File
Weights Calibration & Validation
CATIA 3-D
MODELCONMAP
Aerodynamics Calibration
FLOPS MultiPointAnalysis
737-800FLOPS File
PubliclyRelea sedPerformance Information
1
2
3
Aerodynamics Validation
AerodynamicValidation
Performance
Comparison
0. 00
2. 00
4. 00
6. 00
8. 00
10. 00
12. 00
14. 00
16. 00
18. 00
20. 00
0. 000. 1 0 0 .2 0 0 .3 0 0 .4 0 0 .500. 600. 700. 8 00. 9 0 1 .00
ach
L /
o r
* a x L /
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0. 0 0 0 0 0 . 0 2 0 0 0 . 0 4 0 0 0 . 0 6 0 0 0 . 0800
C
C L
HistoricalAerodynamic Trends
Weight StatementComparison
737-800FLOPS File
Final737-800FLOPS File
PubliclyReleased B737-800Weight Information
IF FLOPS = CONMAP
IF FLOPS = PUBLIC
CONMAP FLOPS
We ight (lb) We ight ( lb) [lbs] [%]
Structure 51433.8 51743 309.2 0.60%
Wing 19230.6 19391 160.4 0.83%Horizontal Tail 1411.2 1408 -3.2 -0.23%
Vertical Tail 1490.5 1487 -3.5 -0.23%
Fuselage 18055.2 18135 79.8 0.44%
Alighting & Arresting Gear 7289.4 7364 74.6 1.02%
Engine Section & Nacelle 3956.9 3958 1.1 0.03%
Miscellaneous 0.0
Propulsion 13259.1 13259.0 -0 .1 0.00%
Engine Installation 10468.0 11246 -0.1 0.00%
Afterburner 0.0
Exhaust System 0.0
Accessory Gearboxes/Drives 562.7
Engine Controls 79.3
Starting System 136.0
Fuel System 1029.1 1029 -0.1 -0.01%Miscellaneous (Thrust Reverser) 983.9 984 0.1 0.01%
Systems & Equipment 23883.0 24090.0 207.0 0.87%
Flight Controls 3421.3 3445 23.7 0.69%
Auxiliary Power Plant 934.0 933 -1.0 -0.11%
Instruments 656.6 660 3.4 0 .52%
Hydraulics & Pneumatics 1418.4 1428 9.6 0.68%
Electrical System 2378.2 2400 21.8 0.92%
Avionics 1620.0 1634 14.0 0 .86%
Furnishings & Equipment 12343.9 12491 147.1 1.19%
Air Conditioning & Anti-Icing 1010.7 999 -11.7 -1.15%
Load & Handling 100.0 100 0.0 0.00%
Weight Empty 88575.9 89092.0 516.1 0.58%
Crew and Baggage - Flight 420.0 420 0.0 0.00%
Crew and Baggage - Cabin 1050.0 1050 0.0 0.00%Engine Oil 120.0 120 0.0 0.00%
Fuel, Unusable 138.0 138 0.0 0.00%
Passenger Service 1031.9 1040 8.1 0.78%
Clean Operational Weight 91335.8 91860.0 524.2 0.57%
Cargo - Containers 0.0 0
External Fuel Tanks & Provisions 0.0 0
Miscellaneous 0.0 0
Operational Weight 91335.8 91860.0 524.2 0.57%
Passengers 27540.0 27540 0.0 0.00%
Passenger Baggage 6480.0 6480 0.0 0.00%
Cargo - Containers (Baggage only) 1296.0 1307 11.0 0.85%
Cargo (Chosen to match TOGW) 1548.0 1548 0.0 0.00%
Fuel, Usable - Internal 46000.0 45917 -83.0 -0.18%
Takeoff Gross Weight 174199.8 174652.0 452.2 0.26%
Delta
A similar processwas used to
calibrate these toolsfor hybrid wing-body
vehicles using a
Northrop Grummaninternal database of all-wing aircraft.
DTOGW=0.26%
FLOPS Aerodynamic Calibration
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• Takeoff and landing max CL
and low-speed drag polarsdetermined throughhistorical trends
• High-speed drag polarscalculated internally inFLOPS
• Calibrated to match publicallyreleased performancecharacteristics
• Validated against historicaltrends for tube-and-wingaircraft of similar grossweight and passenger count
FLOPS Aerodynamic Calibration
66
FLOPS737-800
CATIAFile
FLOPS SinglePointAnalysis
737-800CONMAP File
Initial737-800FLOPS File
737-800FLOPS File
Weights Calibration & Validation
CATIA 3-D
MODELCONMAP
Aerodynamics Calibration
FLOPS MultiPointAnalysis
737-800FLOPS File
PubliclyRelea sedPerformance Information
1
2
3
Aerodynamics Validation
AerodynamicValidation
Performance
Comparison
0. 00
2. 00
4. 00
6. 00
8. 00
10. 00
12. 00
14. 00
16. 00
18. 00
20. 00
0. 000. 1 0 0 .2 0 0 .3 0 0 .4 0 0 .500. 600. 700. 8 00. 9 0 1 .00
ach
L /
o r
* a x L /
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0. 0 0 0 0 0 . 0 2 0 0 0 . 0 4 0 0 0 . 0 6 0 0 0 . 0800
C
C L
HistoricalAerodynamic Trends
Weight StatementComparison
737-800FLOPS File
Final737-800FLOPS File
PubliclyReleased B737-800Weight Information
IF FLOPS = CONMAP
IF FLOPS = PUBLIC
A similar processwas used to
calibrate these toolsfor hybrid wing-body
vehicles using a
Northrop Grummaninternal database of all-wing aircraft.
B737-800 Aerodynamic Calibration Points
Fuel Optimization
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Fuel Optimization
67
• FLOPS parametric mode togenerate an array of vehicleswithin the trade space (aspectratio, wing area, thrust)
• Use parser to filterconfigurations based on
mission requirements andgeometric constraints
• Sort candidate configurationsby objective function
• Repeat process, refining tradespace each iteration until
objective function is minimizedwithin an acceptable tolerance
• Subsequent analysis of emissions and acoustics
FLOPS
Vehicle Parser
Configurations
Sorted byObjective Function
Trade Space
Refined
Initial Trade
Space
User Defined
Objective
Function
Optimized
Vehicle
Requirements
and
Constraints
Fuel Burn Objective Function
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68
Fuel Burn Objective Function
• Optimizing solely on mission fueldrives aspect ratio higher with littleregard for vehicle empty weight
• New objective function weightedcombination of both mission fuel and
gross weight – Yielded lower empty weight vehicles
while still allowing for higher aspectratios
– Empty weight serves as a surrogate forvehicle cost
Optimization Methodology cont.
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Optimization Methodology cont.
69
• Effective at examining and refining a large trade space
• Resulted in optimum performance of trade space while satisfyingperformance and geometric constraints
8500
9 0 0 0
9 5 0 0
10 0 0 0
Wing Area, Sw - sq.ft.
T a k e o f f T h r u s t ( p
e r e n g i n e ) ,
T
~ l b
s
Fuel Required
800 900 1000 1100 1200 1300 1400 15001
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2x 10
4
Second-segment Climb
Range = 1600 nm120 Passengers
Std Sea Level Performance
Optimized Configuration
Sample ObjectiveFunction Minimization
System Effectiveness Ratings (SER)
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• SER metrics defined in order toquantify configuration performancerelative to the 2030-2035 futurescenario and the N+3 goals
• Take into account the benefits and
penalties of technologies at thesystem level
• No extra credit is given forconfigurations that exceed individualN+3 goals
• Penalties• Noise, fuel burn, and emissions SER < 0
for negative system impacts
• Field length SER = 0 for configurationswhich do not meet the requirement
System Effectiveness Ratings (SER)
70
4
1iiSERSER
where SER i are the goal-specific system effectivenessratings, and i are scenario-based weighting factors
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
System Effectiveness Rating (SER)Noise
Fuel Burn
Emissions
Field Length
1
Configuration Number
2 3 4 5 6 7 8 9 10 11
Configuration
S y s t e m
E f f e c t i v e n e s s R a t i n g
Sample Configuration SER Comparison
System Effectiveness Ratings (SER)
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Field Length• Goal: Enable metroplex operations,
field length ≤ 5,000 ft
ε= Arbitrarily small positive number
FL=Current configuration field length
Emissions (NO X )• Goal: 75% reduction in NOX emissions
from CAEP/6 requirement
NOxCAEP/6= Max permissible NOX production based on OPR and SLS thrust
NOx=Current configuration NOX production
71
System Effectiveness Ratings (SER)
Fuel• Goal: 70% reduction in fuel burn from
reference vehicle and mission
MFref = Reference vehicle mission fuel
MF=Current configuration mission fuel
ref
ref
fuel MF
MF MF SER
70.0
6 /
6 /
75.0 CAEP
CAEP NOx
NOx
NOx NOxSER
Noise• Goal: 71 EPNdB reduction in EPNL
from Stage 4 requirement
EPNLStage4= Stage 4 FAR noise limit for vehiclebased on its gross weight
EPNL=Current configuration cumulativenoise
71
4 EPNL EPNLSER
Stage
EPNL
FL floor SERFL
5000
Scenario WeightingFactors
Tools and Processes Review
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• Advanced tools capable of analyzing N+3 vehicles for performance,acoustics, and NAS simulations
• Calibration and validation of tools leads to robustness and higher fidelity
• Optimization process effective at examining large trade space andconverging on optimized configuration
• Metrics and process established for quantifying configuration andtechnology effectiveness relative to N+3 goals
Tools and processes in place to support trade studies for a wide range of
configurations and technology suites
Outline
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• Introduction• Scenario Development
• Requirements Definition
• Design Tools and Processes
• Candidate Configurations and Technologies
• Air Vehicle Design Studies• Technology Maturation Plans
• Summary and Conclusions
• Closed session with NASA partners
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N+3 Phase I Final Review:Candidate Configurations and
Technologies
Nicholas Caldwell, Peter Keding, Chris HarrisNorthrop Grumman Corporation
Contract NNC08CA86C
NASA Glenn Research Center21 April 2010
Reference Vehicle
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• Vehicle used as baseline for establishing current-year capability
• Perturbation on a 737-500, assuming constant technology• Resized to meet mission requirements
• “Rubber Engine”, “photographically scaled” wing
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Units 737-500Reference
Vehicle# Passengers [] 123 120
Range [nm] 2,400 1,600
Ramp Gross Weight [lb] 133,500 120,170
Empty Weight [lb] 68,860 67,350
Fuel Weight [lb] 42,186 25,048
Wing Reference Area [ft^2] 1,135 1,280
Wing Sweep [deg] 25 25
Wing Span [ft] 94.9 100.4
Wing AR [] 7.9 7.9
T/W Ratio [] 0.3 0.34
Max Wing Loading [psf] 117 94
Balanced Field Length [ft] 8,630 4,497
Landing Field Length [ft] 4,450 4,996
Candidate Configurations andTechnologies
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Technologies
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Technologies
Airframes
Engine Architectures
• Engine Architecture Concepts
• Airframe Concepts
• Advanced Technologies
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Engine Architecture Concepts
Reference Engine
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CFM56-3B1(Scalable Reference Engine)
Specifications:• Maximum Thrust: 20,000 lbf
• Cruise SFC: 0.67 pph/lbf • Overall Pressure Ratio: 22.4 (sea level)• Fan diameter: 60” • Bypass ratio: 6.0 (sea level)
Scalable reference engine was carried through the study to serve asa baseline against which to derive fuel burn improvements
CFM56-3B1 chosen due to its use on the Boeing 737-500
Advanced Engine Architectures
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Open Rotor• Low fuel consumption
• High noise potential• Weight of gearbox and
rotors
Three-Shaft Turbofan• High BPR (~18) = propulsive efficiency• High OPR (~50) = thermal efficiency
• Low noise
• Low weight
All engines modeled with constant Cv (velocity
coefficient) of 0.995, base Cd (discharge coefficient) of 0.995, no bleed, and constant inlet pressure recovery
Geared Turbofan• High BPR = propulsive efficiency• High OPR = thermal efficiency
• Low noise• Low weight
Advanced Engine Comparison
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• The geared and three-shaftturbofans exhibit nearly identicalfuel performance for a constantlevel of technology
• Three-shaft turbofan and openrotor show 44% and 60% reduced
fuel burn, respectively, at maxtakeoff thrust compared to thereference engine
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0 5000 10000 15000 20000 25000
S p e c i f i c F u e l C o n s u m p t i o n ,
p p h / l b f
Net Thrust, lbf
Geared Turbofan
Three-Shaft Turbofan
0.00
0.05
0.10
0.15
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0.25
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0.35
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0 5000 10000 15000 20000 25000
S p e c i f i c F u e l C o n s u m p t i o n ,
p p h / l b f
Net Thrust, lbf
Three-Shaft Turbofan
Open Rotor
CFM56-3B1 Turbofan
Max T/OIdle
Initial engine candidates
Refined engine candidates
Sea Level Static
Engine Down-Selection
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• Scalable reference engine is maintainedthroughout the study to serve as abaseline
• Geared turbofan set aside due to its
similarities to the three-shaft turbofan
• Open rotor showed the best sea levelstatic fuel consumption
• Open rotor maintained for further
investigation regardless of its potentialnoise penalties
Open Rotor Geared Turbofan3-Shaft Turbofan
Open Rotor 3-Shaft TurbofanCFM56-3B1
Initial Engine Candidates
Final Engine Candidates
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Airframe Concepts
Initial Design Space
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Advanced Tube-and-Wing(ATW)
• Higher recovery propulsioninstallation• Low fuselage drag• Compatible with high aspectratio wings• Drag and wetted area of external nacelle
ATW with EmbeddedPropulsion
• Noise shielding benefits• Potential reduction in nacelledrag and wetted area due toremoval of engine pods• Propulsive efficiency penalties• Possible ingestion of fuselageboundary layer
• Physical integration challenges
HWB with EmbeddedPropulsion• Noise shielding benefits• Potential reduction in
wetted area due to removalof engine pods•
Hybrid-Wing-Body(HWB)• Higher recovery propulsioninstallation
• Noise shielding benefits• Centerbody sized bypassenger count• Drag and wetted area of external nacelle
• Centerbody sized by passenger count• Propulsive efficiency penalties• Possible ingestion of fuselage boundary layer• Physical integration challenges
Hybrid Wing-Body Sizing Constraint
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6 Foot Height
Constraint
Aft Spar Location
Home Plate Area Used
to Calculate Number of
Passengers
Plan
View
Closure Angle
Constraint
• Minimum centerbody height determined by passenger height• Centerbody volume sized by number of passengers• Wing spar location and propulsion integration dictates length of centerbody and thickness-to-chord ratio
Minimum centerbody size determined by passenger count, regardless of mission
Initial Design Space
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Channel Wing• Reduced field length
• Increased wing wetted areaand weight• Channel sized by rotordiameter• Incompatible with turbofanengines• Physical integration
challenges
Low Aspect Ratio SpanLoader (LARS)• Induced drag is a balance of aircraft weight and aspect ratio
• More efficient passengerloading/unloading• Platform for distributedpropulsion systems
Joined Wing• Lower structural weight• Low fuselage drag• Good transonic aerodynamic
properties• Excess wetted area andinterference drag• Minimal engine noiseshielding due to engineplacement and wing size
ATW with Canard• Unconventional stability and
control• Higher induced drag due toadditional lifting surface• Higher recovery propulsioninstallation• Low fuselage drag
Qualitative Down-selection
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• Wide range of configurationsconsidered in initial designspace
•Considerations:
• Propulsive efficiency• Predicted aerodynamicperformance• Packaging issues
• Smaller subset of candidateconfigurations selected basedon this qualitative assessment
Initial Design
Space
Qualitative Down-select
Qualitative Down-selection
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• Based on a quantitative
analysis that looked at factorsrelevant to the N+3 goals, threeconfigurations were eliminated
• A smaller subset of configurations was considered
further
Initial Design
Space
Qualitative Down-select
Quantitative Down-select
Quantitative Down-selection
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• All vehicles designed to meet
5,000 ft field length requirement- Conventional high-liftsystems proved sufficient
• Remaining requirements usedfor downselection
Initial Design
Space
Qualitative Down-select
Quantitative Down-select
Use of reliever
airports
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Advanced Technologies
Technology Assessment Overview
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• Initial technology databaseidentified over 100 candidatetechnologies for the N+3 timeframe
• QFD process sorted technologiesbased on scenario weighting
factors
• Candidate technologies selectedfrom QFD results and modeled inFLOPS and MIDAS
INTEGRATE TECHBENEFITS INTO
FLOPS Air VehicleDesign Study
Quality Function Deployment (QFD)Process
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• Input from SMEs used to ratetechnologies with respect to each N+3metric
• Scenario weighting factors used toproduce Technology Effectiveness Rating
(TER)
• Further assessed based on TRL andinteraction with other technologies
• Sorted technologies downselected to amanageable number for more detailedinvestigation
Extensive Technology Database
QFD Analysis
Sorted Technologies
Candidate Technologies
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• Noise – Inverted Flow Nozzle
– Landing Gear Fairings
– Landing Gear Assembly Component Integration
– Deployable Vortex Generators
• Aerodynamics – Distributed Exhaust Nozzle & Flap
– Steady Circulation Control
– Swept-Wing Laminar Flow
– Modeling for Inlet Optimization• Airframe
– 3D Woven Pi Preform Joints
– Advanced Metallic Structural and Subsystem Alloys
– Ultrahigh Performance Fiber
– Carbon Nanotube Electrical Cables
– Affordable Large Integrated Structures
– Integrated Aeroservoelastic Structures
• Propulsion – Intercooled Compressor Stages
– Lean-Burn CMC Combustor
– CMC Turbine Blades
– Compressor Flow Control
– Active Compressor Clearance Control
– Lightweight Fan/Fan Cowl
– Fan Blade Sweep Design
– Swept Fan Outlet Guide Vanes
– Variable Geometry Nozzle
filtered by projectedtechnology
readiness insideN+3 time window
All-inclusive technology QFD Candidate Technologies
Used on FinalConfiguration
Not Used on FinalConfiguration
For use on subsequent charts:
Inverted Flow Nozzle
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• Discipline: Noise
• TRL Level: 4
• Primary Metric Addressed: EPNL• Consequences of Failure: Severe
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Inverts high-temperature core flow and thelow-speed cooler fan flow to generate twomixing interfaces for the core stream
Increased mixing capacity of the primarystream leads to reduced noise generation
• Benefits: Reduced jet noise
• Penalties: Increased weight, decreasedthrust, increased engine complexity
• Modeled in MIDAS as a conservativebroadband jet source noise reduction
• Modeled in FLOPS as weight andpropulsive penalties
Baseline Flow
Inverted Flow
Inverter/20-lobe mixerconfiguration (w/ acoustic
shield) at NASA ARC
Landing Gear Fairings
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• Discipline: Noise
• TRL Level: 8
• Primary Metric Addressed: EPNL• Consequences of Failure: Minimal
Passive method to streamline the landinggear assembly during low altitudeoperations
Reduces vortex shedding due to bluff-bodynature of nose and main landing gear
• Benefits: Reduced landing gear drag,noise
• Penalties: Increased weight
• Modeled in MIDAS as a conservativebroadband source noise reduction
• Modeled in FLOPS as a drag reduction andweight penalty on each of the landing gearassemblies
Sample Faired LGBoeing 737 MLG
Landing Gear Component Integration
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• Discipline: Noise
• TRL Level: 8
• Primary Metric Addressed: EPNL• Consequences of Failure: Minimal
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Integration of smaller landing gear assemblycomponents into larger, more conciseparts leads to reduced noise and landing
gear dragMinimizes exposed small parts reduces flow
turbulence and small-scale vortexshedding
• Benefits: Reduced landing gear drag,noise
• Penalties: Increased complexity, more
difficult maintenance• Modeled in MIDAS as a conservative
broadband source noise reduction
• Modeled in FLOPS as a drag reduction oneach of the landing gear assemblies
Fully Dressed B737-300 NLG
Deployable Slat Vortex Generators
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• Discipline: Noise
• TRL Level: 4
• Primary Metric Addressed: EPNL• Consequences of Failure: Minimal
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VGs are small vanes on the scale of theboundary layer used to delay the onset of flow separation by generating vortices
which promote mixing and re-energize theboundary layer
Forces the flow to remain attached whichleads to a decrease in noise in a narrowlow-frequency range, but increases noisein the high-frequency range due to thedevelopment of small scale turbulence
• Benefits: Reduced narrowband noise
• Penalties: Increased weight
• Deployable VGs have been modeled into
the wing slat and weight penalty• Modeled in MIDAS as a as frequency-
dependent noise attenuation
• Modeled in FLOPS as weight penalty
ONERA ExperimentalSetup to Investigate
Static VGs
ComputationalStudy of VortexDevelopmentInduced by
VGs
Distributed Exhaust Nozzle (DEN) andFlap
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• Discipline: Aerodynamics/Acoustics
• TRL Level: 2
• Primary Metric Addressed: CD,, CL,max,EPNL, Weight, Thrust
• Consequences of Failure: Moderate
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Flap
Engine exhaust is ducted through small portsin the wing flap
The blowing is used for circulation control as
well as preventing flow separation overflaps
Exhaust flow is converted to small jets whosenoise signature is characterized by higherfrequencies which are more readilydamped by the atmosphere
• Benefits: Increased max lift coefficient withreduced noise footprint
• Penalties: Increased weight and complexity,decrease in thrust, increase in drag
• Modeled in MIDAS as a as frequency-dependent noise attenuation
• Modeled in FLOPS as weight, propulsive, andparasite drag penalties in addition to a max CLincrease
Turbulence Intensity Contours
DEN and FlapConfiguration
Round jet
DEN
Steady Circulation Control
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• Discipline: Aerodynamics
• TRL Level: 3
• Primary Metric Addressed: CL,max, CD,Weight, Thrust
• Consequences of Failure: Moderate
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Extracts engine bleed for jet blowing overround trailing edge surface to increase lift
Blown sheet of air remains attached to round
circulation control (CC) surface which actsas a BL control at low blowing flow rates
At higher blowing rates, blown flow staysattached to CC TE which moves the airfoilsstagnation point and streamline to thelower surface of the airfoil
• Benefits: Increased max lift coefficient
• Penalties: Increased weight andcomplexity, decreased thrust
• Modeled in FLOPS as weight, propulsive,and parasite drag penalties in addition to amax CL increase
Swept-Wing Laminar Flow
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• Discipline: Aerodynamics
• TRL Level: 4
• Primary Metric Addressed: CD
• Consequences of Failure: Moderate
Delaying the onset of turbulent flow on thewing leads to cruise drag reduction.
Natural swept-wing laminar flow is achieved
through optimal selection of airfoil andwing shapes and advanced manufacturingtechniques
Foreign-object debris can lead to prematureturbulent transition which will penalize thedrag-reducing effectiveness of the wing
• Benefits: Reduced skin friction drag onthe wing
• Penalties: Susceptibility to failure, lower
CLmax, constrained MDD
• Required slat removal modeled in MIDAS
• Modeled in FLOPS as percentage of surface(s) in laminar flow region
Sensor Craft Laminar Flow
Natural Laminar Flow Control
Modeling for Inlet Optimization
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• Discipline: Propulsion
• TRL Level: N/A
• Primary Metric Addressed: TSFC• Consequences of Failure: N/A
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Propulsion flow-path and integration effectsmodeling tool for complex inlet geometries
MDO tools and analysis allow for optimumengine configuration and propulsive
efficiency, while reducing drag in certainbody configurations
More applicable with embedded propulsionconfigurations
• Benefits: Increased pressure recovery,improved fuel burn, decrease in drag,increased range
• Penalties: Little benefit with pitot-static
engine configurations• Modeled in FLOPS as an increase inpressure recovery and decrease in drag
Performance ProbabilityFunctions
+IntegrationEffects
3-D Woven Pi-Preform Joints
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• Discipline: Airframe
• TRL Level: 4
• Primary Metric Addressed: Weight• Consequences of Failure: Varies per
application
Enables creation of large integratedcomposite structures and sub-structuresthrough composite pi-joints
Design allows for exploitation of orthotropicproperties of carbon fiber and limits out of plane failure modes
Allows for failure arrest in design
Dry assembly materials removemanufacturing size limitations found onpre-preg systems
• Benefits: Reduction in joint and fastenerweight, reduction in part count andassembly processes, enables larger
integrated structures• Penalties: Increase in cost
• Modeled in FLOPS as weight reduction
Advanced Metallic Structural and Sub-System Alloys
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• Discipline: Airframe
• TRL Level: 5
• Primary Metric Addressed: Weight• Consequences of Failure: Vary per
application
Aluminum and titanium alloys meet highdemand for materials with increasedstructural properties and withstand
elevated temperaturesMaterials exhibit improved strength to weight
ratios and fatigue/crack growth properties
• Benefits: Reduced structural and sub-system weights
• Penalties: Increase in manufacturing cost
• Modeled in FLOPS as weight reduction
Engine Mount
Mixer Nozzle
Ultrahigh Performance Fiber
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• Discipline: Airframe
• TRL Level: 2
• Primary Metric Addressed: Weight• Consequences of Failure: Vary per
application
A high strength low density polymer fiber inwhich the monomers are aligned andfused through chemical bonding along the
length of the fiberHydrogen bonding between fibers and
carbon nanotubes have been absent inprevious composites
Results in increase in strength and positivethermal and flame resistance properties
• Benefits: Reduced structural weight,reduced part count, larger integratedstructures
• Penalties: Increase in manufacturing cost
• Modeled in FLOPS as weight reduction
Hydrogen Bonded Molecularly Aligned Fibers
Carbon NanotubeEnhanced Fibers
Carbon Nanotube Electrical Cables
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• Discipline: Airframe
• TRL Level: 3
• Primary Metric Addressed: Weight• Consequences of Failure: Vary per
application
Carbon nanotubes are manufactured byinjecting fuel and reaction gas into afloating catalyst suspended in a furnace
Can produce CNT threads which can bewoven into a braid and CNT sheets
CNT sheets are extremely lightweight,strong, with good electrical properties
CNT braids are extremely lightweight, strong,and have slightly reduced electricalproperties
• Benefits: Reduced electrical systemweight
• Penalties: Increase in electrical systemcost
• Modeled in FLOPS as weight reduction
Affordable Large Integrated Structures
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• Discipline: Airframe
• TRL Level: 4
• Primary Metric Addressed: Weight• Consequences of Failure: Vary per
application
Advancements in alloy, composite, andcomposite joint technology allow moredesign flexibility toward unitized structures
Developments in materials reduces weight
while new methodology further reducesweight
Eliminates structural discontinuities andfastened assemblies, increasing structuralefficiency
Reduction in part count
• Benefits: Reduction in structural weight,lower manufacturing time and cost
• Penalties: Possible limits on vehicle life,structure must be more robust to avoidrepair, increased part complexity,constrained design volume
• Modeled in FLOPS as weight reduction
Fuel floor, skin, and
bulkhead jointintersection
Integrated Aeroservoelastic (ASE)Structures
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• Discipline: Airframe/Aerodynamics
• TRL Level: 5
• Primary Metric Addressed: Weight• Consequences of Failure: Catastrophic
Utilization of directional stiffness into aircraftstructural design to control aeroelasticdeformation which benefits aerodynamics,
control, and structure in a positive wayStructural weight no longer primary factor in
wing design, but should include otherdisciplines
MDO improves design efficiency by designing awing to meet specific loads, flightconditions, and performance
• Benefits: Reduced structural and controlsystem weight
• Penalties: Increase in manufacturing costand time
• Modeled in FLOPS as weight reduction
Intercooled Compressor Stages
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• Discipline: Propulsion
• TRL Level: 3
• Primary Metric Addressed: TSFC• Consequences of Failure: Minimal
Reducing the temperature of the compressedflow between compressor stages increasesthe thermal efficiency of the engine
because less work is required to compresslower temperature gas
Intercooler can not completely drop theintermediate flow to ambient temperature,as there will always be an efficiencyassociated with its heat exchange capacity
• Benefits: Reduced fuel consumption,increased thrust, reduced emissions
• Penalties: Added engine weight due tothe presence of the intercooler
• Modeled by RR-LW
Temperature-Entropy
Diagram of Intercooling Stage
Example EngineDiagram w/
Intercooling Stage
Lean-Burn CMC Combustors
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• Discipline: Propulsion
• TRL Level: 6
• Primary Metric Addressed: NOx• Consequences of Failure: Moderate
Staged combustors incorporate multiple(typically two) distinct combustion zonesserviced by independent fuel injection
systemsDepending on the engine power setting,
different combinations of combustorstages may be used, and the burner canthen be optimized for multiple flightconditions
This level of control allows for emissions tobe more tightly monitored and controlled
• Benefits: Reduced emissions, reducedsensitivity to fuel composition, leanercombustion
• Penalties: Increased engine weight,increased fuel system complexity
• Modeled by RR-LW
P&W ASC Combustor, tested in V2500
CMC Turbine Blades
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• Discipline: Propulsion
• TRL Level: 3
• Primary Metric Addressed: TSFC• Consequences of Failure: Severe
Ceramic matrix composite turbine blades andturbine materials are attractive due to theirhigh temperature tolerance
Without the need to cool the turbine blades,compressor bleed is no longer required,and higher temperatures can be achievedwith the combustor
CMC blades will also weigh less than thoseconstructed from current metallic alloys
• Benefits: Reduced engine weight,reduced fuel consumption, decreasedtakeoff and landing distances
• Penalties: Increased emissions due tohigher combustor temperatures
• Modeled by RR-LW
Ceramic MatrixComposite (CMC)
Turbine Blades
Compressor Flow Control
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• Discipline: Propulsion
• TRL Level: 4
• Primary Metric Addressed: TSFC• Consequences of Failure: Minimal
Extracting or diffuser bleed flow and injectingit into the compressor face in order totailor the compressor flow to minimize the
likelihood of stall or surgeCan be used to control flow distortion or to
dampen flow instabilities that areassociated with stall or rotating surge
Requires sensors and control system todetect and control the instabilities or flowcharacteristics that need to be dampened
• Benefits: Reduced likelihood of compressor surge or stall, increasedengine performance
• Penalties: Engine bleed must becompensated by increased performance,increased engine weight
• Modeled by RR-LW
Active Compressor Clearance Control
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• Discipline: Propulsion
• TRL Level: 4
• Primary Metric Addressed: TSFC• Consequences of Failure: Minimal
Tip clearances can vary depending on flightconditions, engine power settings, etc.
Active compressor clearance control provides
higher compressor efficiencies byminimizing blade tip losses by maintainingtip clearances through active means
Generally takes the form of variable, flexibleclearance control maintained byelectromagnetic actuators
• Benefits: Higher component efficiencies,improved TSFC
• Penalties: Added engine weight
• Modeled by RR-LW
Mach contoursshowing flow
separation due to tipclearance effects
Vortex formation due to tipclearance effects
Lightweight Fan/Fan Cowl
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• Discipline: Propulsion
• TRL Level: 3
• Primary Metric Addressed: TSFC, FieldLength
• Consequences of Failure: Moderate
Through optimization of the engine front-endstructure using light weight material, ashorter (lower wetted area) nacelle is
achievableThis technology also allows for mounting of
AGB closer to the engine core, reducingnacelle diameter and hence drag
• Benefits: Weight, reduced nacelle drag
• Penalties: Lighter engine requires morestructural weight in the wing
• Modeled by RR-LW
Short bypassnacelle Core front mount
(Weight/performance)
Lifted intake(performance/noise/drag)
Core mountedgearbox
(drag)
OGV tangential lean(noise/weight/performance/drag)
Bypass shaping(noise)Conventional
Fan Blade Sweep Design
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• Discipline: Propulsion
• TRL Level: 8
• Primary Metric Addressed: TSFC, EPNL• Consequences of Failure: Minimal
Introducing sweep into the fan bladesminimizes the occurrence of shocks on thefan blade tips
This increases fan efficiency by minimizingpressure losses
Fan efficiency also increased by allowing forthe formation of a more favorableboundary layer
• Benefits: Reduced noise, increased fanefficiency
• Penalties: Blade complexity, axial length
• Modeled by RR-LW
Conventional Fan Blades Swept Fan Blades
Mn contours a) conventional b) swept blade
Swept Fan Outlet Guide Vanes
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• Discipline: Propulsion
• TRL Level: 5
• Primary Metric Addressed: TSFC• Consequences of Failure: Minimal
Introducing sweep into the fan outlet guidevanes has the potential to reduce pressurelosses
By delaying the impact of turbulent rotorwake on OGV, noise reduction isachievable through this design strategy
• Benefits: Reduced noise, increased fanefficiency
• Penalties: Blade complexity, axial length
• Modeled by RR-LW
Vane Sweep Angle[deg]
Swept Fan OutletGuide Vane
Shape Memory Alloy Nozzles
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• Discipline: Propulsion/Noise
• TRL Level: 5
• Primary Metric Addressed: EPNL, TSFC• Consequences of Failure: Moderate
Variable geometry nozzles utilize a SMA actuated hinge that is able to be variedand controlled as seen on many modern
military aircraft Allows for optimization of engine for given
power setting and flight condition
Noise generated from engine is proportionalto diameter of the nozzle exit squared andto the exit velocity to the eighth power
• Benefits: Reduced Noise
• Penalties: Decrease in fuel efficiency,increase in nozzle weight
• Modeled by RR-LW
Variable-area exhaustnozzle: fully open Variable-area exhaustnozzle: reduced area
Double Degree-of-Freedom InletLiner
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• Benefits: Reduced Noise
• Penalties: Decrease in fuel efficiency,increase in weight
• Modeled in MIDAS as frequency-dependent noise attenuation
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• Discipline: Noise
• TRL Level: 8
• Primary Metric Addressed: EPNL• Consequences of Failure: Moderate
Facesheet
Septum
Contains two layers of absorbing materialand perforated sheets separating thelayers
Absorbing sections divided up into smallercells designed to target specific tonalfrequencies
Trade between absorption capacity and dragfrom the porous face sheet
Candidate Configurations andTechnologies Review
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Open Rotor Geared Turbofan3-Shaft Turbofan
Open Rotor 3-Shaft TurbofanCFM56-3B1
Initial Design Space
Qualitative Down-select
Quantitative Down-select
Use of reliever
airports
Air Vehicle DesignStudies
• Two advanced and one reference engine architectures selected
• Planform down-selection led to the HWB and ATW as the two preferredairframes
• Candidate technologies selected from QFD results and modeled in FLOPSand MIDAS
• Noise – Inverted Flow Nozzle
– Landing GearFairings – Landing GearAssembly Component Integration
– Deployable VortexGenerators
• Aerodynamics – Distributed Exhaust Nozzle & Flap
– Steady Circulation Control – Swept-Wing LaminarFlow – Modeling forInlet Optimization
• Airframe – 3D Woven PiPreform Joints – Advanced Metallic Structuraland Subsystem Alloys
– Ultrahigh Performance Fiber – Carbon NanotubeElectricalCa bles
– Affordable Large Integrated Structures – Integrated AeroservoelasticStructures
• Propulsion – Intercooled CompressorStages – Lean-Burn CMC Combustor
– CMC Turbine Blades – CompressorFlo w Control
– Active CompressorClearance Control – Lightweight Fan/Fan Cowl
– Fan Blade Sweep Design
– Swept Fan Outlet Guide Vanes
– Variable Geometry Nozzle
Candidate Technologies
Outline
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• Introduction
• Scenario Development
• Requirements Definition
• Design Tools and Processes
• Candidate Configurations and Technologies
• Air Vehicle Design Studies
• Technology Maturation Plans
• Summary and Conclusions
• Closed session with NASA partners
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N+3 Phase I Final Review: Air Vehicle Design Studies
Peter Keding, Nicholas Caldwell, Dr. Sam BrunerNorthrop Grumman Corporation
Contract NNC08CA86C
NASA Glenn Research Center21 April 2010
Air Vehicle Design Studies Overview
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• Sizing and Performance
• Aircraft Acoustics
• Aircraft Emissions
• System EffectivenessRating Results
• Preferred Configuration
Aircraft Vehicle Design Study Overview
Air Vehicle Design Studies Overview
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• Sizing and Performance
• Aircraft Acoustics
• Aircraft Emissions
• System EffectivenessRating Results
• Preferred Configuration
Aircraft Vehicle Design Study Overview
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Sizing and Performance Analysis
Advanced Liner Design
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• Design of advanced inlet and fan ductliners to aid in the reduction of noisetowards the N+3 goal levels
• Advanced materials exhibit betterabsorptive properties and are capable of
increased integration
• Advanced two degree-of-freedom linerreduces overall sound pressure level(OASPL) over larger frequency rangethan baseline
• Reduction in OASPL has been shown tobe largely insensitive to power setting
0
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R e d u c t i o n i n O
A S P L ( d B )
Liner Length, in
Inlet Liner
Fan Duct Liner
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100 1000 10000
S o u n d P r e s s u r e L e v e l A t t e n u a t i o n ,
d B
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Baseline Liner
Advanced Liner
Power Setting Altitude, ft Hard Wall Baseline Advanced Hard Wall Baseline Advanced
0 - -5.2 -6.8 - -3.8 -6.9
1,000 - -4.3 -5.7 - -3.3 -5.7
5,000 - -4.3 -5.8 - -3.3 -5.8
Fan Duct Liner Inlet Liner
ΔOASPL, dB
Baseline and Advanced Fan Duct Liner
Sound Pressure Level Reduction
Impact of Liner Length OnOverall Sound Pressure Level
Reduction
Baseline and Advanced Fan Duct/Inlet Liner Overall Sound
Pressure Level Reduction
Analysis of Engine MountingConfigurations
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• Wing- and fuselage-mounted three-shaftturbofan and open rotor configurations useda tube-and-wing baseline airframe
• T-tail design selected for fuselage-mountedengine configurations
– Places horizontal tail out of the engine exhaust – Increases structural weight
• Quantified the performance and weightchange associated with each configuration
• Both mounting configurations wereanalyzed with the addition of laminar flow
a)
b)
Laminar flow regions for: a) clean wing, fuselage-mounted b) wing-mounted turbofan engine
Analysis of Engine MountingConfigurations
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• Wing-mounting resulted in thelowest fuel burn betweenconfigurations – With laminar flow
– Without laminar flow
• Open rotor wing-mountingdismissed due to configurationproblems – Tip clearance
• Engines were fuselage-mounted
for all HWB configurations – Shielding benefits
– No vertical tails to re-size
– Available space
Laminar Flow Integration
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• Conventional leading edge devices willtrip the boundary layer
• Removal of leading edge devicespenalizes maximum lift coefficient
• Wing size and thrust must increase tomeet field performance constraints
• Wetted area increase on HWBoutweighs fuel savings due to reducedskin friction
• Reconciling laminar flow and high-liftdevices would result in improved fuelburn potential
MDD and Sweep Analysis
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• Drag divergence Mach number studies were performed for initial sizing fora range of wing sweeps, thickness-to-chord ratios, and wing technology
• Enables a cruise Mach number up to 0.8 – Meets minimum cruise Mach number of 0.75 defined in mission requirements
Tube-and-Wing HWB
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Aircraft Acoustics
Landing and Takeoff Operations
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• Detailed trajectories were developedfor each configuration below 10,000 ft
• Takeoff/Climb: Federal AviationRegulation (FAR) Part 36 rules permitengine cutback
• Landing/Descent: Used three degreeglide slope for approach, landing
configuration set at outer marker
0
2000
4000
6000
8000
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12000
14000
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0 2 50 00 5 00 00 7 50 00 1 00 00 0 1 25 00 0 1 50 00 0 1 75 00 0 2 00 00 0
A l t i t u d e
, f t
Distance,ft
FLOPS
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0 2 50 00 5 00 00 7 50 00 1 00 00 0 1 25 00 0 1 50 00 0 1 75 00 0 2 00 00 0
A l t i t u d e
, f t
Distance,ft
Altitude,ft
Interpolated EngineData Table
Detailed Trajectories Aircraft Geometry
EPNL
Vehicle Noise Sources
0
2000
4000
6000
8000
10000
0 20000 40000 60000 80000 100000
FlightProfile
Propulsive Noise• Exhaust Mixing
AirframeVibrational
Source Predictions
Propagation PathEffects
SPL WeightingdBA
Duct Propagation /Lining
Internal Engine Noise• Rotational• Combustion
Fan / Stator Noise• Rotational• Broadband
Detection SystemUnaided Human Ear
Muffler / ActiveNoise Control
FlightProfile
Propulsive Noise• Exhaust Mixing
AirframeVibrational
Source Predictions
Propagation PathEffects
SPL WeightingdBA
Duct Propagation /Lining
Internal Engine Noise• Rotational• Combustion
Fan / Stator Noise• Rotational• Broadband
Detection SystemUnaided Human Ear
Muffler / ActiveNoise Control
MIDAS
FAR Part 36 Noise Requirements
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• The FAR Part 36 limits the effective perceived noise level (EPNL)
allowable by aircraft
• Restrictions placed on cumulative EPNL divided into three categories:takeoff, sideline, and approach
• Stage 4 requirements are a function of vehicle gross weight and numberof engines
60
65
70
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0 200000 400000 600000 800000 1000000
S t a g e 3 C o m p o n e n
t E P NL R e q u i r e m e n t ,
E P
N d B
S t a g e 4 C u m u l a t i v e E P N L R e q u i r e m e n t ,
E P N
d B
Gross Weight, lbf
Cumulative
Takeoff
Sideline
Approach
Modeled Noise Source Components
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• OASPL directivities werecomputed for each noisesource at multiple altitudes
•Identified targets for noisereduction
- Landing gear- Slats and flaps- Jet and fan
Example Noise Source Calculation and Directivity
OASPL (dB), Source at 1 ft., Third Octave Band Centers: 20 Hz – 5000 Hz
Configuration Effects on Noise
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• The ATW was found to have the lowest cumulative EPNL betweenairframes
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275
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Reference Vehicle ATW No Technologies HWB No Technologies
E f f e c t i v e
P e r c e i v e d N o i s e L e v e l , E P N d B
Takeoff
Sideline
Approach
Cumulative
ATW HWB
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Aircraft Emissions
Reference LTO Cycle Definition
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• Defined by ICAO Annex 16, Volume II, Aircraft Engine Emissions for allaircraft engines rated above 6,000 lbf
• Conducted at sea level static conditions by varying the engine throttle tosimulate the different portions of the LTO cycle
Power Setting Time, min
Takeoff 100% 0.7
Climb 85% 2.2
Approach 30% 4.0
Idle 7% 26.0
2.1% of cycle time
79.0% of cycle time
Low NOX combustor must be effective across operating range
CAEP/6 NOx Emissions Metric
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i f ii p W NOxt D ,
• Mass of emissions computed as the sum of the fuel flows, NOx production(g/kgfuel), and operational time for each stage of the simulated LTO cycle:
• This value is divided by theSLS thrust of the engine tocompare to the CAEP/6requirement:
F
D p
CAEP/6 requirement is a function of…
N+3 EmissionsGoal
Historical emissionsperformance trends
(F∞ > 20,000 lbf)
OPR, F∞ Thrust < 20,000 lbf
OPR Thrust ≥ 20,000 lbf
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System EffectivenessRating (SER) Results
Technology Packaging
T h l HWB N T h HWB N i T h HWB P f T h
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• Technology suites weredeveloped based on thetechnology SER assessments
• Noise and performance
packages weredeveloped
• Technologies withhighest SER wereretained
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Technology ATW No Tech
Scaled CFM56-3B1 X
Open Rotor X X
Three-Shaft Turbofan X X
Aeroservoelastic Structures X X
M5 Ultra-High Performance Fiber X X
Affordable Large Integrated Structures X X
3-D Woven and Stitched Composites X X
Advanced Metallics X XSwept-Wing Laminar Flow X X
Carbon Nanotube Electrical Cables X X
Landing Gear Fairings X X X X
Landing Gear Integration
Aerothermal Concepts X X
Boundary Layer Ingestion
Steady Circulation Control
Inlet Optimization
Distributed Exhaust Nozzle X X
Vortex Generators X X
ATW Performance Tech
NOT ANALYZED
PR ≈ 1 FOR PODDED INLETS
CONFLICTS WITH LANDING GEAR FAIRINGS, LOWER SYSTEM EFFECT
ATW Noise Tech
Technology HWB No Tech
Scaled CFM56-3B1 X
Open Rotor X X
Three-Shaft Turbofan X X
Aeroservoelastic Structures X X
M5 Ultra-High Performance Fiber X XAffordable Large Integrated Structures X X
3-D Woven and Stitched Composites X X
Advanced Metallics X X
Swept-Wing Laminar Flow
Carbon Nanotube Electrical Cables X X
Landing Gear Fairings X X X X
Landing Gear Integration
Aerothermal Concepts X X
Boundary Layer Ingestion X X
Steady Circulation Control
Inlet Optimization X X
Distributed Exhaust Nozzle X X
Vortex Generators X X
HWB Noise Tech HWB Performance Tech
CONFLICTS WITH LANDING GEAR FAIRINGS, LOWER SYSTEM EFFECT
Major Technology Suites for HWB Configurations
Major Technology Suites for ATW Configurations
Final Configuration SER Comparisons
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• The ATW exhibitsbetter system-levelperformance than theHWB
• The ATW open rotorconfiguration performsslightly better than the
ATW three-shaftturbofan
- Assuming the two
engines have the samenoise output
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
S y s t e m E f f e c t i v e n e s s R a t i n g ( S E R )
Noise Fuel Burn
Emissions Field Length
The ATW is the preferred
configuration
Final Engine Down-Selection
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0.87
0.88
0.89
0.90
0.91
0.92
0.93
0.94
0.95
0.96
0.97
-40 -30 -20 -10 0 10 20 30 40
S y s t e m
E f f e c t i v e n e s s R a
t i n g
EPNL Difference between Configurations, EPNdB
Open Rotor Noise +
Performance Package
Three-Shaft Preferred
Configuration Reference
• No reliable method currentlyavailable to compute open-rotor acoustic levels
• Trade study was performedto quantify the SER sensitivitybetween engines
• Acoustics experts agree thatthis is highly unlikely with
current understanding of thisnoise source
The open-rotor becomes the preferred
engine if no more than ~3 EPNdB louderthan the three-shaft turbofan
The three-shaft turbofan was selected as the preferred vehicle engine
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Preferred Configuration
Preferred Configuration Summary
Phase 1 Preferred Configuration Summary
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Technology SuiteThree-Shaft Turbofan Engine
-Ultra-High Bypass Ratio ~18-CMC Turbine Blades
-Lean-Burn CMC Combustor
-Intercooled Compressor Stages
-Swept Fan Outlet Guide Vanes
-Fan Blade Sweep Design
-Lightweight Fan/Fan Cowl
-Compressor Flow Control
-Active Compressor Clearance Control
-Shape Memory Alloy Nozzle
Swept Wing Laminar Flow
Large Integrated Structures
Aeroservoelastic Structures
Ultrahigh Performance Fibers
Carbon Nanotube Electrical Cables
3-D Woven Pi Preform JointsAdvanced Metallics
Landing Gear Fairings
Advanced Acoustic Inlet Liner
Range (With Reserves): 1,600 nm
Passengers: 120
Field Length Capability: 5,000 ft
Cruise Altitude: 45,000 ft
Design Mach Number: 0.75
Ramp Gross Weight: 80478 lb
Zero Fuel Weight: 71,333 lb
Operating Empty Weight: 46,133 lb
Empty Weight: 43,666 lb
Wing Aspect Ratio: 12.7
Cruise Specific Fuel Consumption: 0.451 pph/lb
Phase 1 Preferred Configuration Summary
111.0
33.3
Dimensions in ft
98.7
12.5
26˚
Aircraft Comparison
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Units 737-500Reference
VehiclePreferred
Configuration
# Passengers [] 123 120 120
Range [nm] 2,400 1,600 1,600
Ramp Gross Weight [lb] 133,500 120,170 80,478
Empty Weight [lb] 68,860 67,350 43,660
Fuel Weight [lb] 42,186 25,048 9,144
Wing Reference Area [ft^2] 1,135 1,280 967.5
Wing Sweep [deg] 25 25 26
Wing Span [ft] 94.9 100.4 111.0
Wing AR [] 7.9 7.9 12.7
T/W Ratio [] 0.30 0.34 0.36
Max Wing Loading [psf] 117 94 83.2
Balanced Field Length [ft] 8,630 4,497 4,999
Landing Field Length [ft] 4,450 4,996 4,906
Fuel Optimization & Advanced TechnologiesMission & Passengers
Dramatic improvements in empty
weight and fuel have been enabledby advanced technologies
Airframe / Engine Matching
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0
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10000
15000
20000
25000
30000
35000
40000
45000
50000
0 0.2 0.4 0.6 0.8 1
P r e
s s u r e A l t i t u d e , h p
~ f e e t
Mach Number, M
143
Start of Cruise: Altitude = 45,000 ft
Weight = 78800 lb
0
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4
6
8
10
12
14
16
18
20
22
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
L / D
Mn
Max L/D
Mn*Max L/D
Flight Envelope
Aerodynamic Efficiency
Design Point
Wing loading for fieldperformance synergisticwith cruise performance
Thrust-to-Weight ratioenables 5000 ft BFL as wellas efficient cruise at FL 450
Weight Fraction Comparison andWeight Statement
System/Components % TOGW Weight lbf System/Components % TOGW Weight lbf100%
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System/Components % TOGW Weight, lbf
Structural 23.9% 19264
Wing 7.9% 6365
Horizontal Tail 0.9% 691
Vertical Tail 0.4% 356
Fuselage 7.9% 6324
Landing Gear 4.4% 3552
Nacelle 2.5% 1976
Propulsion 6.3% 5058
Engines 5.5% 4453
Fuel Tanks & Plumbing 0.8% 605
Systems & Equipment 24.0% 19341
Surface Controls 1.7% 1377
Auxilary Power 0.8% 626
Instruments 0.7% 587
Hydraulics 4.4% 3581
Electrical 1.1% 865
Avionics 1.5% 1232
Furnishings & Equipment 11.8% 9518
Air Conditioning 1.7% 1357
Anti-icing 0.2% 198
Empty Weight 54.3% 43663
Flight Crew & Misc. 3.1% 2470
Crew & Baggage Flight, 2 0.6% 450
Crew & Baggage Cabin, 4 1.0% 800
Unusable Fuel 0.6% 492
Engine Oil 0.1% 70
Cargo Containers 0.8% 658
Operating Weight 57.3% 46133
Passengers & Cargo 31.3% 25200
Passengers 26.8% 21600
Passenger Baggage 4.5% 3600
Zero Fuel Weight 88.6% 71333
Fuel 11.4% 9145
Mission Fuel 11.4% 9145
Max Ramp Weight 100.0% 80478
System/Components % TOGW Weight, lbf
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Reference Preferred
T a k e o f f W e i g h t F r a c t i o n
Fuel
Passengers & Cargo
Flight Crew & Misc.
Systems & EquipmentPropulsion
Structural
D %
-9%
10%
1%
6%
-3%
-5%
Weight fraction changes modest
Largest contributors to gross weight identify future
weight reduction targets
Preferred Performance
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Mach 0.75 Cruise200 nm Reserves
120 Passengers200 nm Reserves
Preferred Vehicle Fuel Burn Reduction
O ll f l d ti t t h l t li d
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0
5000
10000
15000
20000
25000
30000
M i s s i o n F u e l , l b
7514.4
-70%
-63.5%
N+3GOAL
-8.23%
-2.23% -1.19% -1.15% -1.10%
-4.18%
-8.12%
-28.18%
-3.40%
-5.73%
25048 lb
• Overall fuel reduction represents technology set applied as a group
• Propulsion system resulted in largest overall fuel burn reduction
• Aerodynamics, structures, and propulsion disciplines all important towardsachieving fuel burn reduction
Preferred Vehicle Noise Reduction
Ultra high bypass ratio engine ( 18) directly reduces jet noise
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• Ultra-high bypass ratio engine (~18) directly reduces jet noise• Slat removal and landing gear fairings greatly reduced landing/approach noise
• Jet noise further reduced by shape memory alloy nozzle• Fan noise limited by the addition of advanced liner technology
Preferred Configuration EmissionsResults
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• The three-shaft and openrotor engine architecturesgenerate significantly lessNOx emissions thanenforced by CAEP/6
• N+3 emissions goal isachieved through the use of staged combustion enabledby CMC liners
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CAEP/6 Requirement
[g/kN]
Achievement
[g/kN]Δ
Reference 48.3 40.3 -17%
Open Rotor, Fn = 16760 lbf 73.72 10.63 -86%
Three-Shaft, Fn = 14393 lbf 102.9 9.69 -91%
NASA N+3 Goal
75% reduction from CAEP/6
Reference
Preferred Configuration
Outline
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• Introduction
• Scenario Development
• Requirements Definition
• Design Tools and Processes
• Candidate Configurations and Technologies
• Air Vehicle Design Studies
• Technology Maturation Plans• Summary and Conclusions
• Closed session with NASA partners
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N+3 Phase I Final Review:Technology Maturation Planning
Chris HarrisNorthrop Grumman Corporation
Contract NNC08CA86C
NASA Glenn Research Center21 April 2010
Set of Technology Maturation Plans
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• All technologies that were included on the final preferred configurationwere included in the maturation planning
• Internal R&D and relevant external sources were used to compile initial “trajectory” for near-term planning and expectations
• Future planning considered potentials for scheduled risk, as well astechnical risk, so some activities show longer duration than typical
• We are presenting a limited set of the most beneficial technologies
As an example of technology maturation, mixing devices for jet noisereduction were studied in the 50’s (G.M. Lilley) and just recently were
adopted on commerical transport. Approximately 10 years passed from~TRL 4 to certification.
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Virtual Landing Gear Fairings
l d
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• Plasma actuators are viewed asa prime candidate for
implementation since althoughthey offer relatively lowmomentum addition comparedto other active flow actuators,they may greatly affect thecoherent structure of the shedvorticity.
• However, at this low TRL, it isviewed as a prime candidate in aseries of actuator trials, so thatthe most effective controlscheme can be developed.
Swept-Wing NLF / HLFC
Eli i i f h l b
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• Elimination of the slat byintegrating virtual or seamless
leading edge concepts isestimated at a current TRL of 2.• This technology item spawnedfrom a more detailedconsideration of the laminar flowrequirements, not initiallyassumed in the technology QFD
study.• Continued development of newapproaches throughexperimental and computationalapproaches is envisioned,working towards approaches
that are both effective atincreasing CL on a laminar flowwing, and have a tolerablefailure mode that prohibitsimmediate stall.
Swept-Wing Laminar Flow SlatIntegration
Pl t t i d
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• Plasma actuators are viewed asa prime candidate for
implementation since althoughthey offer relatively lowmomentum addition comparedto other active flow actuators,they may greatly affect thecoherent structure of the shedvorticity.
• However, at this low TRL, it isviewed as a prime candidate in aseries of actuator trials, so thatthe most effective controlscheme can be developed.
SMA Variable Geometry Nozzle
V i bl t l
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• Variable geometry nozzlesutilizing SMA materials to
actuate a high-bypass ratio fannozzle are estimated to be at aTRL of 4.• SMA characterizations shouldbe performed to reliably(minimizing hysteresis) actuateat least a 2-position nozzle
practical for takeoff and cruiseoperations.• Investigating the tradeoff between continuously varyingnozzle area, and two or multi-position fixed positions should
be performed by exploringmultiple configurations.
Advanced Structural and SubsystemsMetal Alloys
At t TRL f
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• At a current TRL of approximately 4 (depending on
which material class of several),optimizations of alloychemistries for structural andsubsystem components shouldcontinue to investigate goodcandidates for limited sampleproduction throughout the next
several years.• Near-term goals should focuson higher toughness andstrength in compressive as wellas tensile modes, as well as atelevated temperatures and room
temperatures. High-pressure,dynamic, hydraulic applicationsshould be targeted as well.
Ultra-High Performance CompositeFiber
F the o k to e if
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• Further work to verifyperformance for aircraft panel
applications should focus onusing the status fibers, whichhave known fabrication qualitylimitations, to develop layupprocesses with appropriateresins.• Fiber manufacturing
development must occur inparallel to improve fiberperformance andmanufacturability to reinforcethe TRL 3 level risk.• Coupon testing to examine
basic composite propertiesthrough break tests and surfaceexamination, along with basicstress/strain testing should occurat this stage.
• For moving to TRL 4, improved fibers must beavailable starting in several years followingcoupon testing to advance a simple compositepanel structure through compression and break testing, as well as verifying layup proceduresand the expected resin-fiber interface properties.
Carbon NanoTube Electrical Cables
Carbon nanotube cables are
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• Carbon nanotube cables arecurrently estimated at a TRL of
3, and must be pursued in termsof both core wire performance,and outer mesh conductorperformance (coaxialarrangement).• To reach TRL 4 for both of these components, at least two
years (potentially several) of development is forseen to assessfeasibility of optimized designsfor combined prototypes.• Separate development willoccur on each to adequately
lower risk levels initially, andidentify and isolate technicalhurdles.•For acquiring a TRL of 5,performance of a subsystemprototype installation for amoderately complex electrical
system should be evaluated.
Modeling for Inlet Optimization
• Researchers have
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• Researchers havedemonstrated some components
of low- and moderate-fidelitytransport of fan-face distortionthrough to the bypass duct andcore compressor, but this hasnot been in concert with otheractivities required to bring thiscapability to TRL 4.
• This would also require addingadditional multi-fidelity modelsof inlet losses and integrationeffects to estimate performancequickly for MDO applications.• Handling of complex geometry
requirements (to handle BLI,podded, embeddedconfigurations) passedautomatically through an APIthat must be devolved into a setof modeling constraints shouldbe a cornerstone component.
Large Integrated Structures
• Continued development to
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• Continued development tofurther reduce risk at this level
should include prototypedevelopment activities includingReliability Based Design (RBD)methods for joint designs.• Advanced structural modelsshould be developed to predictperformance at joint component
and integrated structure levels.Weight models should beupdated for system levelevaluations.• A follow-on task foradvancement to TRL 5 is the
implementation of previousdesign and prediction tools todesign/fab/test a largesubstructure in the NASA COLTSfacility.
Aeroservoelastic Structures
• Previous development of
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• Previous development of advanced state-space
simulations, analysis methods,and flutter control lawdevelopment should beleveraged to developed asimplified high aspect ratio wingdesign to be evaluated bytesting of a cantilevered semi-
span wind tunnel model.• A static aeroelastic scaling of this subscale model should besufficient for this activity.Moderate drag reduction andload control goals should be
pursued.• Parallel refinement of requirements for an integratedsystem should be performed andincorporated into future modeldesigns to a practical extent.
Intercooled Compressor Stage
• Evaluation of subscale
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• Evaluation of subscaleconcepts to investigate pressure
loss and cooling performanceshould be performed in the nextseveral years utilizing DOE andother methods to optimizesubsystem-level integration intothe engine.• This should occur in simulated
design flow (flowrates, pressure)conditions downstream of HPCinstallation to bring to TRL 4.• CFD simulations should becarried out to understandpressure loss mechanisms and
improve heat transfer rates.• System concept studies shouldcontinue to use updated modelsfor top-level mission benefits.
Staged Combustor with CeramicMatrix Composite Liner
• Development of the CMC liner
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• Development of the CMC linertechnology should occur in
parallel with this activity so thatthe design for stagedcombustion, which will allowhuge NOx reductions across thepower setting range, canassume CMC availability.• Design and test of injector
concepts for use in stagedcombustion on a flametube tovalidate the design and alsoinvestigate the compatabilitywith alternative fuels.• Diagnostics data from the
previous study will feed aid inevaluating performance on atwo-cup sector test at high OPR,focusing on integration, ignition,lean blowout, and subidleefficiency, as well as the primaryemissions metrics.
Cooled Cooling Air and EndothermicFuel Cooling
• To advance to a TRL of 6 demonstration
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• To advance to a TRL of 6, demonstrationon an integrated, ground-based engine
should be performed. Assessment of flowlevels and heat exchanger pressure losses,with surrogate cooling fluids representativeof cracked fuels (if none are available)should be performed. A low-loss,lightweight heat exchanger design shouldbe validated as a key outcome.
• Developing an array of potentialcandidates of jet fuels in bench-testburners measuring heat sink capability andexothermic properties would elevate thistechnology to a TRL of 4. Simultaneousefforts to de-oxidize the fuel & pursue
other coke-mitigation strategies, althoughnot detailed here, should be made tosufficiently reduce coke deposition due tothe oxidation mechanism across thetemperature range relevant to an inlineturbofan fuel heat exchanger for cooledcooling air.
Outline
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• Introduction
• Scenario Development• Requirements Definition
• Design Tools and Processes
• Candidate Configurations and Technologies
• Air Vehicle Design Studies
• Technology Maturation Plans• Summary and Conclusions
• Closed session with NASA partners
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SELECT Final Review:Summary and Conclusions
Dr. Sam BrunerManager, Advanced Configurations
Northrop Grumman Corporation
Contract NNC08CA86CNASA Glenn Research Center
21 April 2010
Rational Design Process
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NASA N+3Goals
RequirementsDefinition
FutureScenarios
MethodicalTechnologyDownselect
CandidateTechnologies
Engine and Airframe
Architectures
Optimizationand Trade
Studies
Preferred Concept Vehicle
RelevantTechnologiesfor N+3 EIS
Future Scenarios Drive Design
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• Broad future need identified for – Efficient 1600 nautical mile capability
– 120 passenger load
• Prioritized objectives – Reduced fuel burn
– Reduced emissions
– Reduced noise
• Future traffic growth sustainable by – Utilizing existing 5000 foot runways in Metroplex operations
– Contingent upon NextGen enabling technlogy
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Key Enabling Technologies
P l i t
30000
25048 lb
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• Propulsion system – Low SFC
– Low jet velocity
– Low NOx
• Aerodynamics – Swept wing laminar Flow
• Materials
– Light-weight materials – Advanced structural concepts
• Subsystems – Advanced nozzles and inlets
– Landing gear fairings and integration
• Airframe / Engine integration
– Proper matching of T/W and W/S
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0
5000
10000
15000
20000
25000
M i s s i o n F u e l , l b
7514.4
-70%
-63.5%
N+3GOAL
-8.23%
-2.23% -1.19% -1.15% -1.10%
-4.18%
-8.12%
-28.18%
-3.40%
-5.73%
25048 lb
Summary Accomplishments
Northrop Grumman meets all design intents
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• Northrop Grumman meets all design intents. – All goals met except fuel burn
– Fuel burn still represents outstanding improvement
– Achievable with technology possible by 2025
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Solid TRL 6 by 2025 to manage commercial risk
Noise (Cum below Stage 4) -71 EPNdB -70 EPNdB
LTO NOx Emmissions (below CAEP/6) -75% -75%
Performance: Aircraft Fuel Burn better than70%
64%
Performance: Field Length Exploit
Metroplex
Concepts
Exploit
Metroplex
Concepts
Range 1600nm 1600nm
Passengers 120 120
Field Length, TO and Ldg (SL, Std Day) 5,000 feet 5,000 feet
Cruise Mach 0.75 0.75
Cruise Altitude < FL450 < FL450
N+3 (2030-2035
Service Entry)
Advanced Aircraft
Concepts Goals
(Relative to User-
Defined Reference)
Mission
RequirementsDerived from Traffic
Study
Conclusions
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• Northrop Grumman’s preferred concept is revolutionary inits performance, if not in its appearance
• Breakthrough performance is obtainable via cascadingbenefits in a variety of areas
• Several topics deserve further study in Phase II
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