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“The Airplane That Could!”
Haoyun FuSuzanne Lessack
Andrew McArthurNicholas Rooney
Jin YanYang Yang
Critical Design ReviewDecember 6th, 2008
Agenda
Criteria
Preliminary Designs
Down Selection
Features
Trade Studies
Wing and Empennage Design
Fuel Tank System
Center of Gravity / Static Stability
Take-off and Landing Analysis
V-n Diagrams
Wing Air Loads
Load Path
Cost Analysis
2
Criteria
3
Relief Delivery Mission
30 ton payload
2,500’ takeoff distance
Cruise speed ≥ Mach 0.8
500 nm cruise range
Wet grass, 3,000’ by 200’ landing zone
Transoceanic Mission
10 ton payload
2,500’ takeoff distance
Cruise speed ≥ Mach 0.8
3,200 nm cruise range
Wet grass, 2,500’ by 200’ landing zone
Air Force FDCV Mission 65 ton payload
5,500’ takeoff distance
Cruise speed ≥ Mach 0.8
5000 nm cruise range (one refueling)
Wet grass, 3,500’ by 200’ landing zone
4
Takeoff
Climb
500 nm cruise
Land
Climb Loiter
Divert
Loiter Attempt to
Land or
Land
Takeoff
Climb
500 nm cruise
Climb
RTB cruise
Land and
Unload
Cargo
Loiter
Land
Loiter
Relief Mission Divert Profile
Relief Mission Return to Base Profile
Takeoff
Climb
3200 nm Cruise
Attempt
to Land
or Land
Climb
Divert
Loiter
Land
Loiter
Transoceanic Mission Profile
Takeoff
Climb
5000 nm Cruise/Air
Refueling
Attempt
to Land
or Land
Climb
Divert
Loiter
Land
Loiter
FDCV Delivery Mission Profile
Preliminary Designs Red Configuration
FEMA Mission
Low Wing
Three Engines
Conventional Empennage
5
White Configuration
FEMA Mission
High Wing
Two Engines
T-Tail Empennage
Blue Configuration
Air Force FDCV Mission
High Wing
Four Engines
H-Tail Empennage
Preliminary Design ComparisonCriteria Red White Blue
Mission FEMA FEMA Air Force + FEMA
Range (nm) 3,200 3,200 2,800
WTO (lbs) 184,000 184,000 602,000
WE (lbs) 89,600 89,600 262,000
T/W 0.41 0.41 0.33
W/S (psf) 77 77 114
Mach Cruise Speed 0.82 0.82 0.82
SL (ft) 2,330 2,330 2,990
STO (ft) 2,370 2,370 3,460
CLmax TO 2 2 2
CLmax Landing 3.2 3.2 3.2
Wing Span (ft) 126 126 188
AR 6.7 6.7 6.7
Fuselage Length (ft) 104 104 160
Landing Stall Speed (knots)
87 87 106
Cost (Millions 2008 USD) $217.3 $215.8 $287.1 6
Down Selection White Configuration -> Thomas
7
Down Selection
8
High Wing Ground clearance for large flaps
Reduced floating effect
Reduced engine-debris encounters
Cargo floor close to ground
Propulsion System Two tractor engines
Externally blown flaps meet required CLmax
Engines more reliable with today's technology
Engines are easy to inspect
Down Selection
T-tail Configuration Reduced horizontal and vertical
stabilizer volume coefficients
End plate effect
Clean air
Single fuselage attachment point
Avoids rudder blanketing at high angles of attack
Cost FEMA: $215.8 million
Air Force: $287.1 million
Cannot justify a more expensive plane for FEMA
9
Thomas Overview and ComparisonCriteria Thomas White Ilyushin IRTA-21 Lockheed C-130 Boeing C-17
WTO (lbs) 192,000 184,000 132,275 164,000 585,000
WE (lbs) 95,200 89,600 N/A 79,291 276,500
Max Payload (lbs) 60,000 60,000 40,785 48,000 170,900
T/W 0.36 0.41 N/A 0.1 (P/W) 0.28
W/S (psf) 86 77 N/A 94 161.84
Range (nm) 3,200 3,200 1,349 2,832 4,200
Cruise Mach 0.82 0.82 0.65 0.46 0.77
SL (ft) 2,490 2,330 4,430 2,550 3,000
STO (ft) 2,450 2,370 4,270 3,050 7,740
CLmax TO 2 2 N/A N/A N/A
CLmax Landing 3.32 3.2 N/A N/A 4.75
Aspect Ratio 7.4 6.7 N/A 10.1 7.2
Clean Stall Speed (knots)
126 119 N/A N/A N/A
Landing Stall Speed (knots)
82 87 N/A 100 104
10
Thomas Dimensions
11
Thomas Features
Cockpit
Two Flight Crew
One Loadmaster
One Potential Observer
Loadmaster Station
Desk
Fold-down Chair
Lavatory
Closet
12
Interior Design and Layout - Cockpit
13
Interior Design and Layout: Lavatory, Closet, and Loadmaster Station
14
CAD Representation of the Lavatory (upper left), the closet (upper right), and loadmaster station (right)
Landing Gear Layout
15
Thomas Nose Landing Gear Thomas Main Landing Gear
Trade Studies
Drivers
Take-off Distance
Landing Distance
Gross Take-off Weight
Empty Weight
Parameters
Thrust-to-Weight: 0.31, 0.41, 0.51
Wing Loading: 67, 77, 87
Aspect Ratio: 6.0, 6.7, 7.4
16
Trade Studies
17
Aspect Ratio 7.4
Thrust-to-Weight 0.36
Wing Loading 86
Gross Take-off Weight (lbs) 189,500
Optimized Parameters:
Wing DesignCriteria Thomas
Take-off Weight (lb) 192,000
Wing Loading (lb/ft2) 86
Reference Area (ft2) 2,380
Aspect Ratio 7.4
Span (ft) 133
Sweep (degrees) 28
Dihedral (degrees) -3
Super Critical airfoils:
Boeing 737c @ root
RAE 5213 @ tip
Aerodynamic twist
-3 degrees
18
High Lift and Control Devices
High Lift Devices:
Externally blown flaps 25% of chord
Slats 20% of chord
Control Devices:
Ailerons 30% of chord
Spoilers
Criteria Thomas
CLmax 3.32
Clean CLmax 1.7
Delta Flaps CLmax 1.32
Flaps % of Span 14%-74%
Flaps c'/c 1.25
Delta Slat CLmax 0.3
Slats % of Span 14%-90%
Slats c'/c 1.2
Aileron % of Span 75%-99%
19
Aerodynamic Parameters
ParameterThomas @
Cruise Condition
Lift Coefficient 0.2156
Drag Coefficient 0.0500
Moment Coefficient -0.2677
Oswald Efficiency 0.97
Incidence Angle (deg) 0.83
Spiral Stability 0.71
20
Empennage Design T-tail
NACA 0009 Airfoil
Passed One-Engine-Inoperative test
21
Parameter Horizontal Tail Vertical Tail
Volume Coefficient 0.95 0.76
Aspect Ratio 4.25 1
Taper Ratio 0.45 1
Sweep Angle (°) 33 45
Incidence Angle (°) 0 0
Dihedral (°) -3 0
Tail Area (ft2) 845 340
Propulsion System Pratt & Whitney PW2043 turbofan
PW2000 series/F117-PW-100
used on Boeing 757, Ilyushin Il-96M,
and Boeing C-17
22
PW2000 Series
Fan Tip Diameter (in) 78.5
Length (in) 141.4
Take-off Thrust (lbf, PW2043) 42,600
Bypass Ratio 6
Weight (lbf) 8,721
Specific Fuel Consumption (lb/lbf-hr) 0.35
Fuel Tank System
Transoceanic Mission requires 70,000 lbs of fuel
Nose and forward fuselage tanks move fuel CG location from 45 ft to 30 ft
“Fuel management” provides CG stability during loading
23
Parameter Thomas
Wing Fuel Tank Weight (lbs) 87,800
Wing Fuel Tank Volume (gal/ft3) 13,000/1,740
Nose Fuel Tank Weight (lbs) 8,400
Nose Fuel Tank Volume (gal/ft3) 1,200/170
Forward Fuselage Fuel Tank Weight (lbs)
10,200
Forward Fuselage Fuel Tank Volume (gal/ft3)
1,500/200
Fuel Tank System: Nose and Forward Fuselage Fuel Tanks
24
Nose Fuel Tank
Fuselage Fuel Tank
Fuel Tank System: Wing Fuel Tanks
25
Center of Gravity Excursion and Static Stability
CaseX Center
of Gravity (ft)
XbarCenter of Gravity
Static Margin
(%)
Empty 50.5 2.45 5
Empty + Loading Cargo + Fuel (Loading Payload)
50.7 2.46 4
Empty + Loaded Cargo + Crew (Landing)
49.5 2.40 9.6
Empty + Loaded Cargo + Crew + Full Fuel (Take-off)
48.7 2.36 12.2
Center of Gravity
Total Excursion: 8.2%
Neutral Point: 51.6 ft
Passes longitudinal, lateral, and ground clearance tests
26
90000
110000
130000
150000
170000
190000
2.350 2.400 2.450 2.500
Wei
gh
t (l
b)
Xbar CG (normalized by MAC)
Landing
Take-off
Loading
Empty
Take-offSegment Thomas
SG (ft) 284
SR (ft) 650
ST (ft) 1,560
SC (ft) 0
Total Take-off distance (ft)
2,494
27
Meets take-off distance requirement
< 1% margin
Height after Transition: 154 ft
Balanced field Length: 900 ft
Landing
Meets landing distance requirement on wet grass
< 1% margin
Calculated without thrust reversers
Built in safety factor of 1.66
Segment Thomas
Sa (ft) 450
SF (ft) 630
SFR (ft) 540
SB (ft) 1,120
Total landing distance (ft)
2,490
28
V-n Diagrams: Minimum Weight Condition (121,000 lbs)
29
V-n Diagrams: Maximum Weight Condition (192,000 lbs)
30
Wing Air Load Distributions Minimize aircraft weight while meeting safety
standards
The aircraft structure must:
Withstand the proof load without detrimental distortion
Not fail until ultimate load has been achieved.
Obtain distributed load on wings by combining AVL results with the proper equations.
Finite element method used to calculate aerodynamic loads in the body-fixed coordinate system.
31
32
Bending Moment in the X-direction for Maximum Weight
Load Path Layout Longerons and Stringers
Fuselage Bulkhead
Wind Box Carry-through
Wing Spars
Manufacturer Cost Overview
Cost Analysis Results are given in Millions of 2008 USD
Customer price and Net Present Value Program Profit are based on 10% margin rate
34
Thomas
RDT&E $3,208
Flyaway $4,319
Program Cost(RDT&E + Flyaway)
$7,527
Program Cost per Plane $215.1
Customer Price per Plane
$236.6
Contribution Margin $103.8
Breakeven Quantity 31.8
NPV Program Profit $752.7
FEMA Life-Cycle Cost
Cost Analysis Results are given in millions of 2008 USD
Operating Cost per Flight Hour in 2008 USD: $16,500
Life-Cycle Cost is based on an aircraft service life of 21 years
35
Thomas
Program Cost(RDT&E + Flyaway)
$7,527
Customer Price per Plane
$236.6
Operating Cost $12,520
Operating Cost per Plane
$357.7
Disposal Cost $210.1
Total Life Cycle Cost $21,011
36
Design Methodology Historical Aircraft
Preliminary Sizing
Initial Cost Analysis
Three Configurations
Red, White, and Blue
CATIA models
Detailed Design Aspects
Down-Select Process
Refined Thomas Aircraft
V-n Diagrams
AVL Analysis
Structural Loads
Revised Cost
3D Printing Model37
Aircraft Sizing Preliminary Sizing
Take-off
Climb
Cruise Speed
Ceiling
Landing
Thrust-to-Weight and Wing Loading
38
Relief Transoceanic
Thrust-to-Weight Ratio 0.35 0.41
Wing Loading (psf) 95 77
CLmax Take-off 2.0 2.0
CLmax Landing 3.2 3.2
Individual WeightsItems Relief Mission
Weights (lb)Transoceanic
Mission Weights (lb)
Wing 21,450 21,450
Horizontal Tail 3,855 3,900
Vertical Tail 1,646 1,600
Fuselage 38,195 38,200Main Landing Gear 7,495 7,500Nose Landing Gear 1,320 1,300
Installed Engines 18,420 18,400
Payload 60,000 20,000
Crew 615 615
Fuel 36,600 70,000
WE 95,200 95,200
WTO 192,000 185,800
Utilize Composites
39
Landing Gear Sizing
40
Criteria Thomas
Nose Total Tire Load (lb) 23,000
Main Total Tire Load (lb) 207,000
Nose Gear Bogeys 1
Main Gear Bogeys 4
Nose Gear Wheels / Bogey 2
Main Gear Wheels / Bogey 2
Nose Weight per Wheel (lb) 11,500
Main Weight per Wheel (lb 25,900
Nose Tire Diameter (inch) 25
Main Tire Diameter (inch) 40
Nose Tire Width (inch) 7
Main Tire Width (inch) 14
KEbraking (106 ft-lb/s) 12
Positioning
41
Landing Gear Position Thomas
Xng(nose landing gear) ft 16.2
Yng(nose landing gear) ft 0
Zng(nose landing gear) ft 3
Xmg (main landing gear)ft 58
Ymg (main landing gear)ft 5.9
Zmg (main landing gear)ft 3
Ztip(the height of the tip of the fuselage from the ground)
12.4
This configuration passes the longitudinal tip-over test, lateral tip-over test, and meets the ground clearance criteria.
Thomas Design Cost Overview -Preliminary Design Review Estimates DAPCA IV Results (in Millions of 2008 USD)
Red White/Thomas Blue
RDT&E $2,946 $2,946 $8,626
Flyaway $3,967 $3,920 $24,004
Program Cost(RDT&E + Flyaway)
$6,913 $6,866 $32,631
Program Cost per Plane $197.5 $196.2 $261.0
Customer Price per Plane
$217.3 $215.8 $287.1
Contribution Margin $103.9 $103.8 $95.1
Breakeven Quantity 31.8 31.8 113.642
Assumptions Used to Separate RDT&E Costs and Flyaway Costs
HoursPercentage Spent in
Development (RDT&E)
Percentage Spent in Production (Flyaway)
Engineering 80% 20%
Tooling 95% 5%
Manufacturing 5% 95%
Quality Control 5% 95%
43
Preliminary Design Review DAPCA IV Model Inputs by Configuration
Model Input Red White Blue
Empty Weight (lbs) 90,000 90,000 262,000
Takeoff Weight (lbs) 184,000 184,000 602,000
Max Speed (knots) 530 530 530
Production Quantity 35 35 125
Flight Tested Aircraft 2 2 4
Total Engines 105 70 500
Engine Max Thrust (lbf) 25,000 37,000 50,000
Engine Max Mach 0.84 0.84 0.84
Engine Turbine Temperature (ºR)
2,560.00 2,560.00 2,560.00
Cost Avionics Rate/pound $5,219 $5,219 $5,219
Avionics Weight Percentage
3.00% 3.00% 2.00% 44
Empennage Design
45
One-Engine-Inoperative 25°rudder deflection
Take-off conditions, where speed is the lowest and, consequently, the moment created by the rudder deflection is the lowest
46
Critical Engine-Out Yawing Moment
(lb·ft)
Drag-Induced Yawing Moment
(lb·ft)
Sum of Critical Engine-Out and Drag-Induced
Yawing Moments (lb·ft)
Moment due to Rudder Deflection
(lb·ft)
760,000 189,000 949,000 2,806,000
Balanced Field Length Take-off field length required, including obstacle
clearance, if an engine fails at a speed at which the stop distance and the remaining take-off distance are equal
Minimum required is 2000 feet with a 50 feet obstacle clearance
Value for Thomas is around 900 feet
47
48
Figure 1: Shear loading in the X-direction for critical points with maximum weight
49
Figure 2: Shear loading in the Z-direction for critical points with maximum weight
50
Figure 4: Bending Moment in the Z-direction for critical points with maximum weight
51
Figure5: Torsional Moment in the y-direction for critical points with maximum weight
52
Figure 6: Shear loading in the X-direction for critical points with minimum weight
53
Figure 7: Shear loading in the Z-direction for critical points with minimum weight
54
Figure 8: Bending Moment in the X-direction for critical points with minimum weight
55
Figure 9: Bending Moment in the Z-direction for critical points with minimum weight
56
Figure10: Torsional Moment in the y-direction for critical points with minimum weight
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