Conceptual Design Review
AAE 451
Andrew Mizener
Diane Barney
Jon Coughlin
Jared Scheid
Mark Glover
Michael Coffey
Donald Barrett
Eric Smith
Kevin Lincoln
Outline
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Mission and Concept
Sizing
Design Choices
Aerodynamics
Propulsion
Structures
Weights and Balance
Stability and Control
Cost
Summary and Conclusions
Our Mission and Requirements
• Mission Statement:
– To design a profitable, supersonic aircraft capable of TransPacific travel to meet the needs of airlines and their
passengers around the world.
• Major Design Requirements
– Trans-Pacific Range
• Longer range increases available routes
– High Cruise Speed
• Makes shorter trip times and allows for more legs per day
– Good Cruise Efficiency
• Lowers the cost of fuel and the max gross weight
Marketing and Sales
• Passengers
– High Speed Travel
– Comfort
• Airlines
– Passengers who place high value on their time
– Capstone Aircraft
• Expect to sell 120 Aircraft
– Projecting market growth to 2020
– Based on Key City Pairs
• Long enough to provide time savings
• Travelled enough to provide market foothold
Progress
Walk-Around
40 Passenger
Luxury Cabin
Under-Nose Cameras
for Landing Assist
Cranked-Arrow
Wing Planform
Canards for Pitch Control
and Low Boom
Vertical Tail
(No Horizontal Tail)
4 Low-Bypass Turbofans
Under Wing
Key Design Parameters
• General Performance
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Range: 4800 nmi
Passengers: 40
Length: 190 ft
Takeoff Distance: 11,400 ft
Landing Distance: 7,380 ft
• Weight
– W0 = 329,000 lb
– We = 135,000 lb
– Wf = 185,000 lb
• Engine
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Number: 4
Diameter: 4.7 feet
TSL: 35,400 lbs
T/W: 0.425
• Wing
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Wing Loading: 130 lb/ft2
Area: 2541.5 ft2
Sweep: 60° — 57°
Span: 80.26 ft
Aspect Ratio: 1.85
• Canard
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Area: 500 ft2
Sweep: 45°
Span: 40 ft
Aspect Ratio: 3.2
• Sonic Boom
– Overpressure: 0.36 lb/ft2
Design Mission
• Los Angeles (LAX) – Tokyo (NRT)
– Range: 5,451 nautical miles
– Reduced from LAX – PDG to save weight
Orthographic Projection
Cabin Layout
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Length: 70 feet
Aisle Width: 26 inches
Aisle Height: 76 inches
Seat Pitch: 40 inches
Design Choices
• Joined Wing
– Major structural concerns
– Unclear aerodynamic benefits
– Too complex for time allotted
• Double Delta
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Simple structurally
Good efficiency at high and low speeds
Large internal volume
Weight benefits
• Double Delta chosen
– Final design technically a
“Cranked-Arrow”
Cranked-Arrow
Planform
(Herrmann, 2004)
Design Choices
• Engine Placement
– Under-wing or Podded on Fuselage
– Compared against each other for 8 design considerations
– Both broke even: 4+, 4– Most important design considerations:
• Noise, Weight, Maintenance
• Under-Wing won 2 of 3
• Under-Wing Engines chosen
Design Choices
• Longitudinal Control Surface
– Canards
– Horizontal Tail
• Design necessitated long moment arm
– Wing placed at aft of aircraft
– Engines at aft
• Horiz. Tail required much longer aircraft
or excessively large control surface
• Canards give correct moment arm
without increasing length of aircraft
– Additional benefit of boom reduction
• Canards chosen
Canard Design for
Low Boom
(Yoshimoto, 2004)
Sizing
Design Parameters
• Developed own MATLAB code
– based on Raymer Ch. 19
• Finds Empty Weight and Fuel
Weight Based on Initial W0 Guess
• Uses a Rubber Engine Model
based on Hill & Peterson
AR
T/W
W0/S
S
Mcruise
number of Crew
number of Pax
weight per Crew
weight per Pax
Design Range
cruise altitude
wind speed
stall speed
t/c
ΛLE
CLmax
Number of Engines
1.85
0.425
130
2541.5
1.8
3
40
200
220
4800
45000
100
168
0.03
62
1.2
4
lb/ft2
ft2
Mach
lb
lb
nmi
ft
kts
kts
°
Sizing – Modeling Assumptions
• Empty Weight Statistical Equations based on Raymer
• Trajectory through Transonic
• 50 nmi Step Sizes during Cruise to Calculate L/D and
SFC
• No Range Credit for Descent
• Add 6% Reserve Fuel for Diversions & Trapped Fuel
Sizing – Results
W0
(approx)
329,000
lb
Wfuel
(approx)
185,000
lb
Wempty
(approx)
135,000
lb
Range
4800
nmi
Flight Time
7:16
L/Dcruise
8.85
Engine Diameter
4.7
ft
Engine Thrust
35,400
lb
Total Thrust
141,600
lb
Airfoil and Wing Planform
• Airfoil
– Biconvex
– t/c = 3%
• Wing Planform
– Cranked Arrow
– Optimized for European
SCT
– Provides both high and
low speed performance
Lift Prediction Method
• Uses the model given by
Lee, in “An Analytical
Representation of Delta
Wing Aerodynamics”
Delta Wing, AR = 2
(Lee, S. 2005)
Delta Wing, AR = 2.31
(Lee, S. 2005)
Range of Validity for Thin wing and Lifting Line
(Lyrintzis, 2009)
Drag Reduction Technologies
• Leading Edge Vortex
Flaps
– Improves L/D
• Natural Laminar Flow
– Reducing crossflow
component to increase
the transition Reynolds
number
Leading Edge Vortex Flap Effect
(Marchman lll, 1981)
Supersonic Natural Laminar Flow Test Fixture
(NASA Dryden F-15B)
Drag Prediction
• 3 Components of Drag
• Induced
– Lift
– Angle of attack
• Wave
– Area profile
– Mach number
• Parasite
– Geometry
Drag Prediction
• Wave
– Uses rough area profile
– Forms equivalent body of
revolution
– Take’s Mach cuts
– Uses area profile of projected
Mach cuts
• Parasite
– Uses estimated form factor
and wetted area
– Computes Form factor
– Computes coefficient of
friction
Cruise Conditions
Altitude: 45,000 ft
Mach Number: 1.8
Lift: Between 307,000 lbf and 168,000 lbf
Cruise Conditions
Take-Off Conditions
Altitude: Sea-Level
Mach Number: 0.25
Velocity: 180 kts
Lift: 330,000 lbf
Take-Off Conditions
Approach Conditions
Altitude: Sea-Level
Mach Number: 0.38
Velocity: 250 kts
Lift: 166,000
∆CL: 0.075
High-Lift Configuration
• Plain flaps for both take-off and landing
– ∆Clmax 0.9 for landing
– ∆Clmax 0.54 for take-off
Sonic Boom
• Assuming:
– Supersonic corridors with
required sonic boom
overpressure of 0.3 lb/ft2
• Possible by preventing
the shockwaves from
coalescing
• Potential Technologies
– Blunt conical nose
– Arrow Wing
– Increasing aircraft length
• Gold Jet Technologies
– Blunt nose and forebody
shaping
– Cranked Arrow Wing
Sonic Boom Prediction
• Based upon Carlson
– “Simplified Sonic-Boom
Prediction”
• Uses a series of nonlinear factors based on
altitude and shape
• Determines
– Overpressure
– Duration
Overpressure
• Cruise Condition
– M = 1.8
– Alt = 45,000 ft
• Intermediate Process
– Unmodified Overpressure:
1.5 lb/ft2
– Overpressure with SSBD
shaping: 0.94 lb/ft2
• Results
– Overpressure: 0.36 lb/ft2
– Duration: 0.14 seconds
– Assumes full-aircraft
shaping equivalent to SAI
QSST
Propulsion
• Low Bypass Turbofan without Afterburner
– Number of Engines: 4
• Minimize Engine size / Drag
• Minimize Engine noise
– Specifications (per Engine)
• Engine Dimensions
– Fan Diameter: 4.7 ft
– Engine Length: 17.5 ft
– Inlet and Duct length: 22.2 ft
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Max SLS thrust: 35,361 lbs
Max Cruise (45k, 1.8) Thrust: 9,102 lbs
Cruise TSFC: 0.9492 (lbm/hr)/lbf
Bypass Ratio: 0.5
Overall Compressor Ratio: 20
Engine Model
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Rubber Engine - Created Engine model to allow for multiple engine
configurations to determine optimum
Thermodynamic model based on Hill and Peterson’s model for a Turbofan
Used the following assumptions:
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Fan Pressure Ratio: 1.6
Turbine Inlet Temperature: 1500 K
Fuel Heating Value: 45,000 kJ/kg
Component Efficiencies:
• Diffuser Efficiency: 0.97
– After external compression during supersonic
operation
• Fan Efficiency: 0.85
• Compressor Efficiency: 0.85
• Burner Efficiency: 0.99
• Turbine Efficiency: 0.90
• Core Nozzle Efficiency: 0.98
• Fan Nozzle Efficiency: 0.97
Thermodynamic Engine Model
Engine Performance Optimization
TSFC vs Compressor Pressure Ratio
T04 = 1500 K, BPR = 0
2
1.8
1.6
TSFC [(lbm/hr)/lbf]
1.4
1.2
TSFC Rise for PR < 20
M = 0, Alt = 0
Optimum Cruise PR = 70
1
M = 0.8, Alt = 30k
M = 1.8, Alt = 45k
0.8
0.6
0.4
0.2
0
0
10
20
30
40
50
60
Compressor Pressure Ratio
70
80
90
100
Engine Performance Optimization
Specific Thrust vs Compressor Pressure Ratio
T04 = 1500 K, BPR = 0
0.03
Specific Thrust [lbf/(lbm/hr)]
0.025
0.02
Optimum Cruise
PR = 5
M = 0, Alt = 0
0.015
M = 0.8, Alt = 30k
M = 1.8, Alt = 45k
TSFC – Specific Thrust Trade-off
Overall Optimum PR = 20
0.01
0.005
0
0
10
20
30
40
50
60
Compressor Pressure Ratio
70
80
90
100
Engine Performance Optimization
TSFC vs Bypass Ratio
T04 = 1500 K, CPR = 20, FPR = 1.6
1.2
High Bypass Ratio means
larger engine to meet thrust
demands
TSFC [(lbm/hr)/lbf]
1
0.8
M = 0, Alt = 0
0.6
M = 0.8, Alt = 30k
M = 1.8, Alt = 45k
0.4
0.2
Bypass Ratio = 0.5 gives 0.04 benefit in Cruise TSFC
with minimal increase in Engine Size
0
0
0.5
1
1.5
2
2.5
Bypass Ratio
3
3.5
4
4.5
5
Inlet Design
• 2D Ramp inlet for supersonic external compression
– Double Ramp – 8° turning angles
– Variable Inlet geometry for optimum subsonic and
supersonic performance
Inlet Design
Normal Shock into
Subsonic diffuser
Oblique Shocks
• Supersonic Configuration
- Ramp configuration and
Capture Area designed
for 45k, 1.8 (Cruise)
Design point
Pressure Recovery:
P02/P01 = 0.96
Inlet Width = 4.7 ft
2.39 ft
51.4º
Supersonic Capture
Area
8º
41.7º
3.03 ft
8º
5.42 ft
7.90 ft
Variable Inlet Ramps
•Subsonic Configuration
Inlet Width = 4.93 ft
- Capture Area designed
Sea Level, 0.32 (takeoff)
Sea Level Pressure
Recovery:
Static: M = 0:
P02/P01 = 0.86
Takeoff: M = 0.32:
P02/P01 = 0.97
Subsonic Capture
Area
22.2 ft
8.88 ft
Engine Fan Face
(D=4.7 ft)
Nozzle Design
• Converging-Diverging Nozzle
• Variable Geometry Nozzle for perfect expansion to
ambient conditions
Variable Geometry
Throat
Engine Performance Curves
Design point TSFC = 0.9492
Design point (1.8, 45k)
Design Point installed Thrust
(per Engine) = 9,102 lbf
Design point (1.8, 45k)
Thrust Summary
Thrust Required (Drag) and Thrust Available (4 Engines – 100% Pwr) vs Mach # for
Important Altitudes
Assuming Steady level flight at Max Cruise Weight (307,000 lb)
T req - 0 ft
140000
Treq - 10k ft
Treq - 45k ft
120000
Tavail - 0 ft
Tavail - 10k ft
Tavail - 45k ft
Thrust (lbs)
100000
80000
60000
40000
20000
Max Cruise Speed: M = 1.85
Min Cruise Speed: M = 1.20
0
0
0.5
1
1.5
Mach #
2
2.5
Structure
• s
Load Path
• a
Canard
Keel Beam
Load Path
• a
Wing Box-Keel Junction
Load Path
• a
Main Longerons
Load Path
• a
Main Landing Gear Box
Reinforced Wing Spars
Engine Nacelles
Wing Fuselage Interaction
• s
APU
Aft Fuel Tank
Cargo and Cabin
Emergency Exit
Service Door
Nose Gear
Cargo Door
Keel Beam
Cargo and Cabin
Galley
Lavatory
Fuel Tank 2
Overhead
Compartments
Fuel Tank 1
Canard Box
Fuselage
Windows
Fuselage
Reinforced Deck
Stringers
Fuselage
Ducting
Reinforced
Door Sill
Nose/Cockpit
Elevated
Cockpit
Avionics
Extra Seat
Materials
• GLARE
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GLAss REinforced Fiber Metal Laminate
Used for GoldJet Skin Panels
10% Less density than comparable Al
Excellent fatigue properties
Picture: http://www.ncn-uk.co.uk/DesktopDefault.aspx?tabindex=139&tabid=430
Materials
• Alloy 2090 Al-Li
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Advanced Aluminum Lithium Alloy
8% Density savings v. 7075 Al
10% Higher elastic modulus
Excellent fatigue properties
Used for wing leading edges due to high temperature
properties, as well nose cone (leading edge ̴ 260 °F at Mach
1.8 – Raymer Fig 14.18 and Fig 14.19)
• Conventional Al alloys
– Lower cost
– Easier certification
– Established maintenance
• Steels
– Used exclusively in the landing gear
Landing Gear
• Main Landing Gear
– Placement of the main landing trucks
• Avoid tailstrikes
• Aft of engine inlets
• CG considerations for static stability
Photo courtesy of www.aerospaceweb.org
Landing Gear
• Nose Landing Gear
– Placement of the nose gear
• Based on percentage of total weight carried by nose gear
• Usually 10-15 percent to allow for steering
Photo courtesy of www.aerospaceweb.org
Landing Gear
• Placement of landing gear
– Back end of aircraft at 190 feet from nose and 5.5 feet above
fuselage bottom
– Center of gravity at 132 feet from the nose
– Engine inlets at 145 feet from nose
• Nose gear: 57 feet from nose
• Main gear: 145 feet from nose
– based on 15 percent weight on the nose gear
– These would correspond to the bottom of the fuselage being
6.5 feet off the ground
Landing Gear
• Size of landing gear
– Based on max gross weight of aircraft
– The weight used is weight per wheel
• Number of nose wheels: 2
• Number of main wheels: 8
– Diameter calculations
• Diameter of nose gear: 45.3 inches
• Diameter of main gear: 49.5 inches
– Width calculations
• Width of nose gear: 16 inches
• Width of main gear: 17.5 inches
Component Weights
• Derived from Raymer’s Equations
• Fighter
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Wing
Vertical Tail
Engine Section
Engine Mounts
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Oil Cooling
Engine Cooling
Tailpipe
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Electrical
Air Conditioning
Anti-Ice
Hydraulics
• Transport
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Canard
Landing Gear
Fuselage
Furnishings
Avionics and
Instruments
Weights
Note: These numbers are
overly exact, but are left to
significant digits because they
came from the component
weight equations
Weights
Center of Gravity
Forward CG
Aft CG
• Centers of Gravity (measured from nose)
– Most Forward: 128.63 ft
– Most Aft: 111.808 ft
CG Travel
Cost Model: Purchase Price
• RDT&E and Production Costs computed using
Modified DAPCA IV Cost Model
– (RDT&E + Production Cost) x Profit = Civil Purchase Price
• From Raymer, derived from Hess and Romanoff (1987, RAND
Corporation)
• Includes Engine cost model from Birkler, Garfinkle, and Marks
(1982, RAND Corporation)
– Costs in 1999 $, converted to 2009 $ using the Bureau of
Labor Statistics’ Consumer Product Index (CPI)
• Model of average change over time in prices paid by
consumers for a market basket of consumer goods and
services
– No good projections to 2020 $ available
Cost Model: Operating Costs
• Operating Costs estimated using Raymer
– Three main components, plus Insurance
• Crew Salaries
• Fuel Costs
• Maintenance (Labor and Materials)
– Calculated using:
• 3500 estimated flight hours per year
• Block time/year (from design mission)
• Aircraft speed, weight, and cost
– Costs in 1999 $ projected to 2009 $ using CPI
• Jet A-1 Fuel Price as of April 3, 2009
– From IATA Jet Fuel Price Monitor
Cost Model: Costs
• GoldJet Aerospace FAST Purchase Price:
– $236.78 million (2009)
• Projected Operating Cost:
– $36.9 million per year, per aircraft (2009)
Stability and Control
• Longitudinal stability
– Location of stick-fixed neutral point
• Subsonic: 0.30 ahead of MAC L.E.
• Supersonic: 0.18 ahead of MAC L.E.
– Static margin limits: Between 9% and 70%
Stability and Control
• Trim Diagrams
– All-moving canards used for supersonic flight
– Capable of trim for all flight conditions
Lateral Stability
• Lateral Stability
– Vertical Tail
• Area = 282 ft2
• Sized determined by one-engine out
– Rudder takes up 30% of the tail area
• Rudder deflected 20° to with OEI
• Rudder deflected 10.5° in crosswind
landing
• Roll Control
– Space reserved for ailerons of sufficient size
Turn Time Analysis
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Embraer ERJ 145 as model
– Similar cabin size (50 pax)
– Smaller baggage area
Fuel compared to Boeing 777
Single cargo door
Two rear service doors
All estimates conservative
Turn Time Chart
Aircraft Concept Summary
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Supersonic, trans-pacific flight
40-Passenger luxury cabin
Canards for pitch control
4 Low-bypass turbofan engines below wing
Requirements Compliance
Remaining Steps for Paper
• Carpet Plots
• V-n Diagrams
• Payload-Range Diagram
Concept Plausibility Concerns
• Sonic boom shaping
– Never tested on aircraft of same scale
• Noise
– Takeoff and Landing Noise expected to be considerable
• Cruise efficiency
– Large concern
– Much worse than anticipated
• Weight
– Weight growth always a concern
• Market
– Uncertainty of predicting to 2020
Plausibility Conclusion
The GoldJet FAST, as designed,
could be built economically, but in all
likelihood not flown profitably.
Further Detailed Design
• CFD for canard/engine interference
– Avoid wake and vortex ingestion
• Significant boom shaping assumed for overpressure
– Much analysis required to achieve desired values
• Engine research & design
– Replace rubber engine
• Complex avionics
– fly-by-wire and blind landing
• Structural members
– Sizing and testing
– Temperature Analysis
• Manufacture/Assembly process design
Questions?