Cruise Efficient Short TakeOff and Landing

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Cruise Efficient Short Take-Off and Landing
(CESTOL) Subsonic Transport System (Revolutionary
System Concepts for Aeronautics 05) Hyun Dae
Kim NASA Glenn Research Center Jan. 26, 2006
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Cruise Efficient Short Take-Off Landing (CESTOL)

• Background
• Brief Concept Vehicle Description
• Study Plan
• Graphical Animation
• Presentation by Boeing Technology / Phantom Works
  on Vehicle Configuration
• Q A

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Cruise Efficient Short Take-Off Landing (CESTOL)

• Description of the Problem
• Saturation of airports and the impact to the
  surrounding airspace and terrestrial communities
  are a rapidly increasing limit to world aviation
  travel. Subsonic commercial concepts appearing
  on the 25 year horizon must facilitate a more
  than 4X increase in air traffic, while complying
  with more stringent respect for the surrounding
  communities across the expanding world market.
• Under-utilization of small regional airports
  (e.g., Clevelands Burke Lakefront Airport)
• OBJECTIVE
• Need fuel efficient low noise aircrafts that
  utilize small regional airports to address air
  traffic growth.
• -gt Low Noise Cruise Efficient STOL (CESTOL)
  Vehicle

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Historical High Subsonic Transport Aircraft
Configurations
Boeing 707
De Havilland Comet
Northrop YB-49
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Cruise Efficient Short Take-Off Landing (CESTOL)
New Vehicle Concept

• Embedded Distributed Propulsion Vehicle will
  have
• High lift capability via spanwide vectored
  thrust providing powered and/or circulation
  control lift to enable STOL operation.
• Efficient cruise performance through drag
  reduction by wing wake fill-in with engine thrust
  stream.
• Reduction in aircraft noise through airframe
  shielding and acoustic treatment of the large
  available surface area of propulsion system.
• Improvement in safety through a redundant
  multiple propulsion system.
• Reduction or elimination of a number of
  aircraft control surfaces through differential
  and vectoring thrust for pitch, roll, and yaw
  moments.
• Synergistic vehicle-propulsion integration is the
  key!

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Study Plan
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Graphical Animation of CESTOL Aircraft At
Clevelands Burke Lakefront Regional Airport
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Cruise Efficient Short Take-Off and Landing
(CESTOL) Subsonic Transport System (Revolutionary
System Concepts for Aeronautics 05) Ronald
Kawai Boeing Technology/Phantom Works Huntington
Beach
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Study Scope
Boeing Technology/Phantom Works Huntington Beach
Creates Revolutionary Concept and Develops
Characteristics, Performance, and Identifies
Technology Needs for an Airplane Configuration
Embodying Very Low Noise Features Capable of
Operations from Regional Airports NASA GRC
Separate Contractor Quantifies Low Noise
Potential
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LITERATURE REVIEW
Powered lift can provide high CL for STOL Past
STOL transport studies for regional/short range
at cruise speeds less than Mach 0.8 DSS
turboprops have lowest GW Cost but speed
limited to below Mach 0.7 Efficient Mach 0.8
possible with turbofans or UHB unducted
fans Mach 0.8 requires supersonic tip speed fans
or counter-rotating fans but the later have high
take off and enroute noise A shrouded fan, i.e.
turbofan is needed for high speed with low
noise IBF/USB/Augmentor Wing have highest high
lift efficiency
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Other Studies Show Internally Blow Flap
Has Better High Lift Performance But Judged
Complex
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Extensive studies and analyses resulted in AF
AMST program fly-off between YC-14 and YC-15 IBF
and Augmentor Wing ruled out by hot ducting
complexity
YC-14 and YC-15 where straight wing airplanes
With efficient cruise below Mach 0.7
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YC-14 Interior Noise
Peak at 70 - 100 hz
AFFDL-TR-77-128
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BOEING C-17A

• AF SELECTED THE C-17 WITH EBF TO BECOME THE
  ONLY
• SUCCESSFUL LARGE TURBOFAN POWERED STOL
  TRANSPORT
• (Swept Wing for Mach 0.74 0.77 Cruise, 2750
  nmi range w/164,900 lb
• payload, First flight Sept 15, 1991)
• FUTURE STOL TRANSPORT CONCEPT IMROVEMENT
  OPPORTUNIES
• - IMPROVE CRUISE EFFICIENCY (INCREASE SPEED
  AND RANGE)
• - LOWER NOISE

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2005 Boeing Current Market Outlook
Extrapolation of growth forecast would predict
average airplane size to remain near constant
with increased flight frequencies and city
pairs Future Demand continues for 90 to 175
passenger size Operating from regional airports
would relieve long pre-departure times
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Noise Restrictions can be expected to escalate
with increasing number of flights Very low noise
will be required to enable growth for expanded
operations at existing and new commercial
airports while minimizing noise penalties
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Including a minimum 100 ft runway width for
larger aircraft showed that 84 or 813 of 973
civil airports have 5,000 ft
AIAA 2003-2891, Regional Jet Operational
Improvements resulting from Short Field
Performance and Design
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• Noise Footprint Would Be Very Important at Many
  Other Airports
• Expanded use of regional airports
• Allow relaxation of curfews/operating at night
• Allow increased operations per day
• Allow conversion of military closing to
  commercial use
• Neighbors want low noise regardless of airplane
  weight
• Goal should be cum noise as to Stage 3 minus XX

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STOL to Reduce Noise Footprints
Rapid Climb Out
Steep Approach
Take Off
Sideline
2000m
Approach
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.
TO
.
Sideline
Approach
Low Sideline Noise would be of high value at
Burke Lakefront Airport
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Long Beach, CA Airport
10PM to 7AM curfew 41 flight/day limit can be
raised if aircraft noise decreased
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El Toro Marine Air Base in SoCal could not be
converted to relieve congestion at LAX because
of neighborhood opposition
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2025 Summary
Traffic Growth Forecasts generally for next 20
years For 2025, extrapolate trends from Boeing
Current Market Outlook Noise sensitive regions
are U.S. and Europe Twin aisles and large
airplanes for trans oceanic flights Single aisle
dominates size and generally with many more
take-off and landing operations/day than twin
aisle and large aircraft Reducing noise for
greatest noise growth is thus single aisle
90-175 passenger size Focus on high end for
growth, 170 passenger size, but with BWB, It
becomes multiple aisle airplane Study for use at
regional airports for air traffic expansion that
may provide dual use technology for multi-role
military applications
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• BLENDED WING BODY IS FUTURE CONCEPT FOR
• IMPROVED EFFICIENCY AND LOWER NOISE
• LOW NOISE FEATURES
• Forward noise shielding
• No aft noise reflection
• No flap noise
• Low approach thrust
• Body suppression of landing gear noise

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Benefits From Embedded Distributed Propulsion

• Embedded engines for quiet powered lift
• Close coupled engine to slot with cold low
  pressure fan bleed
• Smaller nozzle diameters for improved jet noise
  shielding
• More rapid mixing moving jet noise source
  forward
• Longer flap chord shielding / nozzle diameter
• Increased atmospheric attenuation form higher
  frequency jet noise
• Reducing engine size enables embedding in mid
  wing sections for more
• forward Cp and Cg
• Reduces the thrust of individual engines reducing
  engine out thrust
• yaw control moments

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Forward Fan Noise Shielding Aft Turbo-machinery
and Combustion Noise Shielding Jet Noise Shielding
Chevrons for mixing
Fan Bleed IBF
Freestream Inlet

• Distributed propulsion
• Smaller exhaust diameters enhances jet noise
  shielding
• Smaller engines enable direct fan bleed for low
  pressure powered IBF
• Slotted ejector reduces powered lift noise
• Minimal engine out rolling moment with powered
  lift

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Concept Development Process

• SOW
• 2025 technology for traffic growth using
  untapped regional airspace
• Cruise efficient configuration with Embedded
  Wing Propulsion

• Review/Summarize Previous Studies
• IBF most efficient powered lift for STOL

• Mission Requirements for CESTOL
• 170 pax, 3,000 nmi, Mach 0.8
• Very low noise
• Minimum 5,000 ft TOFL

• Define Configuration with STOL characteristics
• WingMOD planform development
• Digital configuration development

• Assess System Benefits of Distributed Propulsion
  on CESTOL
• Boeing Integrated Vehicle Design System (BIVDS)
  synthesis
• Very low noise features on Quiet Powered Lift
  Concept

Foundational Technology Needs Outlined
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WingMOD Multidisciplinary Optimization
Configuration Estimate

• Hard Constraints
• Payload
• Range
• Approach Speed
• etc.

• Design Constraints
• Running Loads
• Buffet Characteristics
• DFMA
• etc.

Optimized Config.
WingMOD Optimizer
Baseline Config.
Closed. Balanced. Trimmed. Min. OEW

• Aerodynamics
• Vortex Lattice Model
• Empirical Profile Drag, Compressibility Drag,
  Sectional Maximum Lift
• CFD, Wind Tunnel Calibration

• Controls
• Elevon Model
• Balance Analysis

• Structures
• Monocoque Beam Model
• Stress Buckling Sizing
• Static Aeroelastics

Configuration Layout
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Quiet Distributed Propulsion Starting Point

• Fan bleed slot ejector IBF for quiet powered
  lift
• Short inlet diffuser w/AFC
• Inlet and exhaust noise shielding

• IBF sizing 12 x 6 K lb thrust engines
• Slot width per engine 68.1 in
• Slot height 2.36 in
• Fan pressure ratio 1.69

4 engines
4 engines
4 engines
Injection Slots
272.4 in
272.4 in
137 ft
100 optimization runs to evolve controllable
planform
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Configuration Components All
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Control Surface Usage

• Lift effectors geared to pitch effectors -0.641
  for trim, 0.441 for control
• 10.2 deg flap deflection on lift effectors
• Transition flap geared to pitch effectors -0.291
  for trim, 0.161 for control

Lift effect, pitch and roll control
Yaw and roll control
Pitch control
Pitch and roll control
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BIVDS EvaluationMission Performance
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1st and 2nd Segment Climb
Accel to Final Climb Speed
TO
6,500 m
Performance analyses resulted in about the same
take-off flight paths with the same altitude
over the take-off measuring point at 6,500 m or
21,325 ft from brake release
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Very Low Noise Features
3,500 ft TOFL
Embedded Distributed propulsion enables quiet
powered lift with jet noise shielding
Rapid Climb (3000 ft over T.0. noise
point) Could Use Cutback or Higher Altitude
Before Acceleration to Climb Speed Steep Descent
(6 degree glide slope)
Forward Noise Shielded
Aft Noise Shielded
Consider Part Span Verticals to Improve
Sideline Shielding if Necessary
Note Powered lift is off during climb
Differential elevons positions could be optimized
for noise shielding
Boeing Technology/Phantom Works Huntington Beach
provides mission data for very low noise concept
for NASA to make noise assessment
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Foundational Technologies Needed

• Noise Shielding Codes
• Reflections
• Turbo-machinery noise
• Jet noise

• Inlet/airframe Aero Integration
• Inlets in high Mach flow field

• Quiet Powered Lift
• Low Pressure IBF performance and noise

• Revolutionary Engine Concepts
• Short Cruise Efficient

• Variable Geometry Noise Reflection Nozzles
• Forward noise source

• Flow Control Inlets
• Active, Passive and Hybrid Evaluations

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Reduce Nozzle Height and Create Vortices to Move
Jet Noise Source Forward
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Need Small Turbofan for X-48B
Foundational Technology for Jet Noise Shielding
Shielded Jet Noise Nozzle CFD Development
Shielding Code Development Calibration Wind
Tunnel Tests
Model Tests
Flight Validations
Small Turbofan(s)
Current X-48B program to validate low speed
characteristics
Modify with quiet turbofan for very low noise and
IR validation
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Conclusions
Continuing growth in air travel demand is
forecast. This growth is expected to
increase daily departures operating from an
increasing number of city pairs. This growth is
forecast to go with increasing GDP providing a
need for very quiet airplane operating from
regional airports which can have current
economics Studies have shown eliminating noise
reflections while providing noise shielding
can significantly reduce flyover noise Extending
these principals to jet noise source downstream
in the exhaust wake should provide more dramatic
noise reductions Large surface area planforms
such as the BWB provides opportunities for
increased source noise shielding Embedded
distributed propulsion offers the potential for
quiet powered lift with jet noise shielding for
small noise footprints operating from regional
airports Configuration studies were made to
evolve a BWB STOL planform that is trimmable
with total noise shielding Low noise footprints
would also have low IR footprints for passive
protection from terrorists Development of
foundational technologies are needed that would
be generic and dual use