Perry Overbey Chad Vetter Bill Viste David Perveiler Lee Hargrave Doug Heizer Steve Moss Final...
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Transcript of Perry Overbey Chad Vetter Bill Viste David Perveiler Lee Hargrave Doug Heizer Steve Moss Final...
Perry Overbey
Chad Vetter
Bill Viste
David Perveiler
Lee Hargrave
Doug Heizer
Steve Moss
Final Design Report:Black Lightning
AIAA RFP
Background– Advanced deep interdiction aircraft– Antecedent aircraft
F-117, F-15E, B-1, B-2
Mission Requirements– Supercruise: Mach 1.6– Stealth exceeding F-117– Range: 3500 nm
EL: GOOD BULLET CHART
Configuration Down-Selection
Key Design Parameters Established:– Stealth Requirement– Supercruise Requirement
Several Configurations Proposed:Several Configurations Proposed:
Config. 9
Config. 11
Config. 12b
EL: GOOD COMPARISON
Radar Cross Section (RCS)
Geometric Methods– Number of Planform Angles
– Flat Panel vs. Doubly-Curved
EL: GOOD EXPLANTION
Radar Cross Section
RCS Results:– POFACETS Used for Comparative RCS Measure:
Result: Black Lightning was nearly equivalent
Black Lightning V-Tail (F-117)
EL: NICE ANALYSIS BUT NOT LABELED WELL
GTOW vs A/C Length
100,000
120,000
140,000
160,000
180,000
200,000
220,000
240,000
260,000
280,000
0 20 40 60 80 100 120 140 160 180
A/C Length (ft)
GT
OW
(lb
)
Interdisciplinary Trade Studies
Reduce Gross takeoff Weight to minimize costA/C length trade study
– A/C length 100 ft
EL: GOOD WORK (small # font)
redundant
Avoid single sub-bullets
Trade Studies (cont.)
Wing area– Wing area 2000 ft2
Leading edge sweep– Limited by mach cone– Initial sweep: 51°– Final sweep: 55°
EL: HARD TO READ FONT
Constraint Diagram
Initial design point– T/W = 0.45
– W/S = 110 lb/ft2
EL: TOO BUSY
Results
All performance requirements metMission duration – 4.17 hoursMission radius – 1,750 nmMission fuel required – 56,497 lbBalanced field length
– Standard day – 2,814 ft– Icy runway – 3,524 ft
Landing distance – – Standard day – 3,488 ft– Icy runway – 7,494 ft
EL: Good summary- but watch sig figs
Measures of Merit
2-g Maximum Thrust Specific Excess Power Envelope
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
M
alti
tud
e (f
t)
Stall Limit
q Limit
Engine Design Limit
SEP=0 ft/s
SEP=500 ft/s
SEP=1000 ft/s
Clean ConfigurationManeuver Weight W=98,757 lbs 50% Internal Fuel AIM-120 (2) 2,000 lb JDAM (4)
EL: clean lines
Measures of Merit
Maximum Thrust Maneuvering, Sea Level
0
5
10
15
20
25
30
35
40
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
M
Tu
rn R
ate
(deg
/s)
Clean ConfigurationManeuver Weight W=98,757 lbs 50% Internal Fuel AIM-120 (2) 2,000 lb JDAM (4)
Engine Des ign Lim itMax Load Factor Lim it
q Lim it
Corner VelocitySEP = 0 ft/s
Stall Lim it
Turn Radius = 500 ft
Turn Radius = 1000 ft
Turn Radius = 2000 ft
Turn Radius = 3000 ft
Load Factor, n
2 3 4 5 6 7
EL: Good work but too busy
Aerodynamics
FLUENT Static Pressure Gradient at Trailing Edge of NACA 64-206 at Flight Conditions
EL: Good analysis but big picture?
Parasite Drag
Drag Buildup
0.00E+00
2.00E-03
4.00E-03
6.00E-03
8.00E-03
1.00E-02
1.20E-02
1.40E-02
1.60E-02
1.80E-02
Clean Subsonic Supercruise Takeoff
Par
asit
e D
rag
Landing Gear
Flaps
W ave
Fuselage
W ing
Leaks &ProtuberancesTail
EL: Good buildup
Cockpit
Fuel Tank
Avionics BayWing Tanks
Nozzle and Trough
Diffuser
Inlet Face
Internal Configuration
EL: nice slide
CG Movement
High Fuel Weight– CG Movement Throughout Mission
60000
70000
80000
90000
100000
110000
120000
130000
35 40 45 50 55 60
Feet from Nose of Airplane
Wei
gh
t o
f A
irp
lan
e lb
s
Normal Mission
Aborted Mission
Forward Limit
Aft Limit
EL: no yellow, don’t box figs
Lift Distribution
Computed at 50% Fuel LoadUsed Proportional Distribution for Spanwise LiftUsed to Construct Shear and Bending Moments
Spanwise Lift Distribution Chordwise Lift Distribution-1.4
-1
-0.6
-0.2
0.2
0 0.2 0.4 0.6 0.8 1 1.2
Chord (ft)0
5000
10000
15000
20000
25000
0 10 20 30Half-Span (ft)
Lift
(lb/ft
)
EL: small font, negative chord-wise lift and units?
Wing Structural Layout
• Five Main Spars
• Modeled as Cantilevered I-Beams
• 15 Ribs placed at 24” Intervals
• Analyzed using ANSYS to Find Max. Stresses
EL: nice pics of what?
Propulsion Configuration
Diffuser and Nozzle Configuration
Single Expansion Ramp2-D Ejector Nozzle S- duct for Stealth
Cooling Air Bypass
Shut-Off Doors
Sensors
5% Duct Oversize
EL: good slide
Frontal Dimension and Weight– Comparison with P&W F100– NASA EngineSim
Physical Engine Sizing
BRP 1.1OnX
BRP .72OnX
BRP .72F100 Scaled
M dot Scaled M dotMatchM dot
Get Area
BRP 1.1F100 Rescaled
Scaled Area
EL: equations would have been better than pictures
Diffuser Sizing
EL: good use of published data (citation?)
Stability and Controls
Primary Objectives of S&C– Obtain tail size and geometry– Determine control surface size and arrangement– Determine dynamic stability characteristics
EL: nice image for orientation
Dynamic Stability Analysis
Determination of Subsonic Nondimensional Stability Derivatives – Roskam’s method Based on USAF Datcom
Assumed an effective static margin to account for the stability augmentation system (No equivalent lateral assumption made)
Takeoff Clean LandingShort Period 1 1 1
Phugoid 1 1 1Dutch Roll Below 3 Below 3 1Phugoid --- --- 3
Spiral Mode 1 1 ---Rolling Mode 1 1 ---
1 1 1
MIL-F-8785C Compliance Level
Roll Rate
Longitudinal
Lateral-Directional
EL: good table
Cost Analysis
Unit Price for 200 Aircraft Sold:– $97.08 Million
Operation Cost per Hour: – $13,139 /hr
Price per Pound of Empty Weight:– $1,582 /lb
EL: basis?
Cost Verification
Cost Verification Through Comparison– B-2 Spirit– F-117 Nighthawk– F-15 Eagle
Cost/Empty Weight Black Lightning Comparison
Aircraft $/lb $/lb
B-2 8296 6620
F-117 1499 3366
F-15 883 1169
Same Number of Aircraft Purchased for Each Case
EL: unhelpful comparison
Conclusion
Meets or Exceeds all RFP RequirementsMajor Design Drivers
– Low Observability– Supercruise
EL: good conclusion perhaps bit too simplified
Aircraft Design Review, 9 April 2002
Face audienceUse story links
Know/practice charts(but don’t memorize)
Use pointer for figures