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