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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.
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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: Config. 9 Config. 12b Config. 11 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
Interdisciplinary Trade Studies • Reduce Gross takeoff Weight to minimize cost • A/C length trade study • A/C length 100 ft Avoid single sub-bullets redundant EL: GOOD WORK (small # font)
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
ConstraintDiagram • Initial design point • T/W = 0.45 • W/S = 110 lb/ft2 EL: TOO BUSY
Results • All performance requirements met • Mission duration – 4.17 hours • Mission radius – 1,750 nm • Mission fuel required – 56,497 lb • Balanced 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 EL: clean lines
Measures of Merit 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 EL: Good buildup
Internal Configuration Diffuser Inlet Face Fuel Tank Cockpit Nozzle and Trough EL: nice slide Wing Tanks Avionics Bay
CG Movement • High Fuel Weight • CG Movement Throughout Mission EL: no yellow, don’t box figs
Lift Distribution • Computed at 50% Fuel Load • Used Proportional Distribution for Spanwise Lift • Used to Construct Shear and Bending Moments Spanwise Lift Distribution Chordwise Lift Distribution 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 Cooling Air Bypass Single Expansion Ramp 2-D Ejector Nozzle Sensors S- duct for Stealth Shut-Off Doors 5% Duct Oversize EL: good slide
Physical Engine Sizing • Frontal Dimension and Weight • Comparison with P&W F100 • NASA EngineSim MatchM dot Get Area Scaled Area M dot Scaled M dot BRP 1.1 F100 Rescaled BRP 1.1 OnX BRP .72 OnX BRP .72 F100 Scaled 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) 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 EL: unhelpful comparison Same Number of Aircraft Purchased for Each Case
Conclusion • Meets or Exceeds all RFP Requirements • Major Design Drivers • Low Observability • Supercruise EL: good conclusion perhaps bit too simplified
Aircraft Design Review, 9 April 2002 Face audience Use story links Know/practice charts (but don’t memorize) Use pointer for figures