AircraftAircraft DesignDesign ClassClass
Sam B. Wilson III Chief Visionary Officer AVID LLC www.avidaerospace.com 9 September 2008 TTO Tactical Technology Office
9 Sept.’08 / pg # 2 DesignDesign MethodsMethods
What Size?
What Shape?
9 Sept.’08 / pg # 3 Design “As Drawn”
Computer evaluation of Conceptual Designs “As Drawn” Assumes fixed external mold- lines JSFJSF X-35BX-35B Weight as independent variable - “loop
9 Sept.’08 / pg # 4 closure” IntegrationIntegration Challenge:Challenge:
To design a supersonic fighter/attack aircraft that offers the operational flexibility of Short Takeoff and Vertical Landing (STOVL)
Need to make the same design compromises as a conventional fighter, plus one: use the available thrust in a manner that allows a controlled vertical landing
This single added constraint requires a more systematic approach to the design of an aircraft.
9 Sept.’08 / pg # 5 V/STOLV/STOL AircraftAircraft DesignDesign ProcessProcess Step 1
Define wing & horizontal stabilizer geometry Located engine “vertical thrust” center with respect to aerodynamic center
9 Sept.’08 / pg # 6 Ref NASA CR-177437 V/STOLV/STOL AircraftAircraft DesignDesign ProcessProcess Step 2 Add minimum length inlet/diffuser Add cockpit and forebody
9 Sept.’08 / pg # 7 Ref NASA CR-177437 V/STOLV/STOL AircraftAircraft DesignDesign ProcessProcess Step 3 Add vertical tails Assign location dependent masses landinglanding geargear flightflight controlscontrols radarradar
9 Sept.’08 / pg # 8 Ref NASA CR-177437 V/STOLV/STOL AircraftAircraft DesignDesign ProcessProcess Step 4 Add Payload bays / weapon hardpoints Add fuel tanks Assign location independent masses ServiceService centerscenters AAvionicsvionics APUAPU
9 Sept.’08 / pg # 9 Ref NASA CR-177437 V/STOLV/STOL AircraftAircraft DesignDesign ProcessProcess Step 5 Add lead weight ballast! CGCG tootoo farfar forwardforward VerticalVertical thrustthrust centercenter tootoo farfar aftaft
9 Sept.’08 / pg # 10 OverviewOverview ofof StudyStudy
Description of four candidate propulsion systems which can be based on a single gas generator First order effects of the four propulsion systems on the sizing of a STOVL fighter
9 Sept.’08 / pg # 11 DesignDesign MissionMission
9 Sept.’08 / pg # 12 STOVLSTOVL LiftLift SystemsSystems StudyStudy
Unscaled Propulsion System Weights 5000
4000
front nozzle 3000 ducts C & A 2000 rear/ventral Augmentor
Weight (lb) gas generator 1000
0 RALS RULS MFVT L+L/C 9 Sept.’08 / pg # 13 ThrustThrust toto WeightWeight DefinitionsDefinitions (review)(review) Engine T/W = Uninstalled Max A/B Thrust CTOL Engine Weight
System T/W = Installed Max A/B Thrust Total Propulsion System Weight
Lift System T/W = Balanced Vertical Thrust Total Propulsion System Weight
9 Sept.’08 / pg # 14 STOVL Lift System Performance
System Thrust to Weight 10
8
6 Vertical Thrust 4 Max. Aug Thrust
Thrust / Weight 2
0 R A L S R U L S MFVT L+L/C
9 Sept.’08 / pg # 15 STOVLSTOVL LiftLift SystemSystem BreakoutBreakout
Group Weights 35000
30000
25000 Fuel 20000 Payload Fixed Equip. 15000 Propulsion
Weight (lb) 10000 Airframe
5000
0 R A L S R U L S MFVT L+L/C
9 Sept.’08 / pg # 16 STOVLSTOVL GrossGross WeightWeight SensitivitySensitivity
Design Point Sensitivity 10% change in manuver performance 5
4
3
2 Percent Change 1
0 R A L S R U L S MFVT L+L/C 9 Sept.’08 / pg # 17 CruiseCruise EngineEngine ThrustThrust forfor L+L/CL+L/C
Thrust Distribution 30,000 Lift engine at .42 L C.G. at .58 L 25,000
20,000
15,000 Lift engine Thrust
Thrust (lb) 10,000 L/C eng Vert. Thrust
5,000
0 0.5 0.6 0.7 0.8 0.9 1.0
9 Sept.’08 / pg # 18 Aft Nozzle Location HoverHover BalanceBalance
Thrust Required for Vertical Landing
45,000 40,000
35,000 30,000 25,000
20,000 15,000 10,000
5,000
- 0.42 0.46 0.50 0.54 0.58 0.62 0.66 0.70 0.74 Station Location 9 Sept.’08 / pg # 19 OffOff DesignDesign PerformancePerformance
Fallout Performance
RALS RULS MFVT L+L/C
Ps @ M=1.50, 30k' 410 1123 861 583
Nz @ M=0.60, 20k' 4.05 4.04 4.03 4.05
Nz @ M=1.20, 40k' 3.14 3.77 3.59 3.34
9 Sept.’08 / pg # 20 ConclusionConclusion forfor LiftLift EnginesEngines
If high maneuver performance and/or dry super- cruise is required, lift engines have limited value (mission dependent)
Lift System thrust to weight is not a strong function of engine T/W for many engine configurations
Factors other than mission performance will be necessary to choose a propulsion system
9 Sept.’08 / pg # 21 9 Sept.’08 / pg # 22 CNACNA AirAir PanelPanel StudyStudy - Tactical Air Assets for Carrier Task Force Fighter & Attack Aircraft vs. Multi-Mission Aircraft STOVL vs. Conventional Carrier Based Aircraft No Utility Aircraft Assessments - Used STOVL Strike Fighter TOR Missions Latest Statement of Future Naval Mission Requirement Multi-Mission (F/A & SSF) Do All Missions Subsonic Attack Aircraft Point Designed for Air to Ground "Blue Water" Fighter Optimized for Fleed Air Defense - Emphasis on Time Based Technology Trends Baseline was US/UK ASTOVL "1995 TAD" Assumptions “1990 TAD” Timeframe Allows for "What is Available"
9 Sept.’08 / pg # 23 NASA-AmesNASA-Ames StudyStudy PlanPlan Technology Availability Date Common: Engine Cycle, Weapons, Avionics, etc.
1990-TAD 1995-TAD Radar Absorbing Material + 0% + 5% Internal Weapons Carriage No Yes 1.5M Supersonic Cruise A/B “Dry” Design Load Factor 7.5 9.0 Technology Factor 90% 85% Propulsion System T/W ~12 ~15
9 Sept.’08 / pg # 24 DifferentiatorsDifferentiators ”1990 TAD” Aircraft Class
Fighter Multi-Mission Attack Structural Tech. Factor -10% -10 % -10% Design Load Factor 6.5 g 7.5 g 6.5 g Survivability Impacts No No No Dry Super-cruise No No No Plan form Variable Standard Standard Wing Pivot +30% 0 0 Tail Surfaces Standard Standard Standard
9 Sept.’08 / pg # 25 DifferentiatorsDifferentiators "1995 TAD" Aircraft Class
Fighter Multi-Mission Attack
Structural Factor -15% -15 % -15% Design Load Factor 9.0 g 9.0 g 6.5 g Survivability Impacts No Yes Yes Dry Supercruis Yes Yes No Planform Variable Diamond Flying Wing Wing Pivot +30% 0 0 Tail Surfaces Conventional Conventional None
9 Sept.’08 / pg # 26 AmesAmes CNACNA StudyStudy DescriptionDescription
Three Aircraft Classes Direct-Lift STOVL Sea-Based (“Cat / Trap”) Land-Based Two Technology Timeframes 1990-TAD 1995-TAD Philosophy ACSYNT - Design Synthesis Code
9 Sept.’08 / pg # 27 BaselineBaseline DesignDesign MissionMission 2 min combat 1.5M at 50000 ft 400 nmi cruise Best Altitude and Mach 150 nmi dash 1.5M at 50000 ft High Value Stores Retained for Landing 2 Long-Range, Air-to-Air Missiles 2 Short-Range, Air-to-Air Missiles Gun and Ammo 60 minutes loiter Best Mach at 35000 ft
Loiter 0.3M at Sea Level 250 nmi cruise 0.85M at Sea Level
9 Sept.’08 / pg # 28 AircraftAircraft ClassClass DetailsDetails
STOVL Sea-Based Land-Based
Fuselage Structure 0 + 30 % 0 Landing Gear Structure 0 + 30 % 0 Carrier Approach No Yes No Propulsion Weight + 47% 0 0 Landing Hover T/W 1.16 N/A N/A Reaction Control System Yes No No Duct Volume Penalty ~10% 0 0 Loiter in Pattern 10 min 20 min 20 min
9 Sept.’08 / pg # 29 PropulsionPropulsion SystemsSystems
Conventional
Direct-Lift STOVL
9 Sept.’08 / pg # 30 AircraftAircraft EvolutionEvolution
1995-TAD
1990-TAD
9 Sept.’08 / pg # 31 BaselineBaseline AircraftAircraft
100000 1990-TAD 1995-TAD
80000
60000
40000 Takeoff Weight (lb)
20000
0
STOVL STOVL Sea-Based Sea-Based Land-Based Land-Based 9 Sept.’08 / pg # 32 AugmentationAugmentation inin HoverHover
100,000 1990-TAD STOVL Baseline
Derivative 80,000
60,000
40,000 Takeoff Weight (lb)
20,000
0
9 Sept.’08 / pg # 33 Sea-Based Land-Based STOVL DryDry Super-cruiseSuper-cruise RequiredRequired
100,000 Derivative 1990-TAD Conventional Baseline 80,000
60,000
40,000
20,000 Takeoff Gross Weight (lb)
0
9 Sept.’08 / pg # 34 Sea-Based Land-Based STOVL 1990-TAD1990-TAD GrowthGrowth FactorFactor
25
Sea-Based 20 STOVL Design Mission 15 Radius
10 Growth Factor
5
0 0 100 200 300 400 500 600 700
Mission Radius (nm) 9 Sept.’08 / pg # 35 1995-TAD1995-TAD GrowthGrowth FactorFactor
25
Sea-Based 20 STOVL Design Mission Radius 15
10 Growth Factor
5
0 0 100 200 300 400 500 600 700
Mission Radius (nm) 9 Sept.’08 / pg # 36 RequiredRequired HoverHover ThrustThrust MarginMargin 1995-TAD STOVL
100000
80000
60000
Sea-Based
40000 Land-Based
Baseline STOVL
Takeoff Gross Weight (lb) 20000
1.16 T/W requirement
0 1.15 1.2 1.25 1.3 1.35
T/Whover 9 Sept.’08 / pg # 37 9 SeSept.’08pt.’08 / pg # 3838 9 Sept.’08 / pg # 39 9 Sept.’08 / pg # 40 9 Sept.’08 / pg # 41 9 Sept.’08 / pg # 42 STOVL Baseline Aircraft
Direct Lift Remote Fan L+L/C
T.O. Gross Weight (LB) 36,331 36,866 39,679 Length (ft) 48. 54. 54. Wing Area (ft2) 345. 400. 440. Span (ft) 29.6 32.8 35.1 Thrust (Vertical landing) 29,289 42,142 47,102 Thrust (SLS Dry) 29,289 26,02127,595 Propulsion Weight (LB) 8,381 8,419 10,014 Engine Weight (LB) 7,532 6,723 7,097 Fuel Weight (LB) 11,387 10,698 11,207
9 Sept.’08 / pg # 43 STOVL Aircraft (Ratios)
Direct Lift Remote Fan L+L/C
Growth Factor 3.20 2.37 3.52 Aspect Ratio 2.5 2.6 2.8 Wing Loading (LB/ft2) 105.3 92.2 90.2
Vertical Thrust/WPS 3.49 5.01 4.70 Dry Thrust/TOGW 0.81 0.71 0.70 Max Thrust/TOGW 1.30 1.14 1.12 ESF 1.21 1.08 1.14 Prop. Sys. Fraction 23.1% 22.8% 25.2% Fuel Fraction 31% 29% 28%
9 Sept.’08 / pg # 44 Cruise Efficiency
N.m./100# Cruise Efficency
1818 DL 16 16 LPLC 1414 RFSF 1212
N . 10 M 10. / 1 0 0 8 # 8 66 44 22
0 0 Subsonic M=1.4 9 Sept.’08 / pg # 45 Subsonic 1.4 Mach Number Weight Breakdown
40,000
35,000
30,000
25,000 Fuel Aux. Lift Weight 20,000 Engine Airframe 15,000 Payload
10,000
5,000
0 D.L. L+L/C A.L. Type of A/C
9 Sept.’08 / pg # 46 ConclusionsConclusions Improved engine technology allows the elimination of landing thrust-to- weight as the main STOVL design constraint.
The STOVL propulsion system decision drives the aerodynamic shape.
9 Sept.’08 / pg # 47 EngineEngine WeightWeight vsvs.. EmptyEmpty WeightWeight
9 Sept.’08 / pg # 48 EngineEngine WeightWeight vsvs.. EmptyEmpty WeightWeight
0.80
0.70
0.60
0.50
WEng/OWE 0.40 OWE/WG
0.30
0.20
0.10
0.00
9 Sept.’08 / pg # 49 DistributedDistributed PropulsionPropulsion
DARPA PM: Dr. Thomas Beutner (TTO)
Advanced ESTOL transport configuration development incorporating distributed propulsion technology and airframe / propulsion integration.
Powered high-lift systems • Upper surface blowing • Augmenter wing • Blown tails Tools Used 278-ft field length AVID RAPT 15,000 lb -- 25,000 lb payload AVID HighLift AVID ACS Demonstrated distributed propulsion performance FUN3D Identified new benefits for Distributed Propulsion CFL3D 9 Sept.’08 / pg # 50 USM3D SpanSpan BlowingBlowing versusversus TotalTotal LiftLift
Drag Polars for increasing blown span. Spanloadings for increasing blown span. CT =1.67, 18 deg USB flaps CT=1.67, 18 deg USB flaps
7.0 120
6.0 100
5.0 80
4.0 38% span blowing 38% span blowing 60 55% span blowing 55% span blowing CL
Cl x c 72% span blowing 72% span blowing 3.0
40 2.0
20 1.0
0 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 9 Sept.’08 / pg # 51 y/(b/2) CD NotionalNotional DemonstratorDemonstrator
Canard over door
Variable # of engines used in cruise Small Engines (designed to cruise at best SFC) “blowing” Flaps During STOL Small Engines operations “blowing” Control Surfaces during STOL operations to reduce size
9 Sept.’08 / pg # 52 AVID-ACSAVID-ACS TypeType OutputOutput
Engine is sized by maneuver or VL (1.2*GW) Fuel is generated by Fuel burn: Thrust required = weight/ (L/D) Fuel = Thrust * SFC Airframe weight is structure to hold everything: Fuel tanks = Fuel weight * 3% Landing Gear = TOGW * 6% Tails = Control power sizing Wing = f (AR, Sweep, Area, Taper, T/C)
9 Sept.’08 / pg # 53 ACSYNT Institute: Aircraft Design Tools Parametric design tool for aircraft synthesis...
Concept Preliminary DetailedDetailed Development Design Design ACSYNT •Lots of Designs •In-depth analysis •Detailed analysis •Tradeoff Studies •Narrowed to few designs •Subsystem design & •“Requirements •Detailed optimization optimization Optimization”
9 Sept.’08 / pg # 54 ACSYNT Drawbacks
???
• Practical – Human designer not informed as to why final design was chosen •Technical – Can’t handle step changes (i.e. number of engines, type of control surface). Must use continuous functions in coding.
9 Sept.’08 / pg # 55 Artificial Intelligence for Aircraft Design
PROS CONS • Hailed as “Future of Aircraft • Designers are constantly Design” evolving, requires evolving code •Capture the thoughts of the “great designers” and apply to • Conflicting inputs from computer aided design conflicting designers programs •Impossible to recreate spontaneous thoughts of humans
9 Sept.’08 / pg # 56 Goals of Computer Aided Aircraft Design Optimization Programs
• Reduce dependence on wind tunnel testing • Computer code offers “Real Time Design” • Much smoother transition from paper to prototype • Reduces common “headaches” associated with current aircraft design • No more “Point Design”
9 Sept.’08 / pg # 57 http://aero.stanford.edu /reports/nonplanarwing 9 Sept.’08 / pg # 58 s/CWingOpt.html UnmannedUnmanned AirAir VehiclesVehicles
100000 Global Hawk Dar kstar Pr edator Gnat 750 Chir on 10000 Hunter Firebee Model 410 Exdrone Eagle Eye Model 350, M1 Outrider 1000 Huntair STM 5B Theseus Spectr e II Model 324, M1
100 Shadow 600 Skyeye Pioneer Pathfinder Hawk-i 7B Porter Per seus B Raptor DARPA MAV Prowler Fr eewing 10 Shadow 200 Truck
Total Weight, kg Tern LADF 9” 3.8# Aerosonde 1 Javelin Gasoline Electric Pointer Turbine 0.1 Black Widow 0.01 0.1 1 10 100 Wing Span, m Vehicle data ex cept MAV from NASA GSFC / Wallops UAV Database 9 Sept.’08 / pg # 59 http://uav.w ff.nasa.gov /db/uav _index.html MicroMicro AirAir VehiclesVehicles
MicroSTAR Kolibri 100 g. 320 g. 5 km range, 30 min. 30 min. Autonomous Nav. Hover/translate Video imagery GPS Autopilot Lockheed Sanders Mentor Lutronix 50 g. electrostrictive polymer artificial muscle Flapping flight Microbat Stanford Research Institute 10 g. 3 min. Black Widow Acoustic sensors MEMS wings Caltech 50 g. 1 km range Teleoperated Video imagery
9 Sept.’08 / pg # 60 AeroVironment Kolibri Micro Air Vehicle
Flight Speeds Max. demonstrated flight speed in hover mode: 22 kts Max. predicted flight speed transitioned flight mode: 88 kts Min. turn radius (for maneuvering): 0 ft Max. rate of climb demonstrated at 0 kts forward speed: 4800 fpm Max. controllable rate of descent demonstrated: 1700 fpm Endurance Max. predicted endurance with no payload: 34 minutes Demonstrated endurance with mission package: 16 minutes Range Max. hover-mode range predicted: 15 nmi (ferry range) Max. transitioned range predicted: 50 nmi (ferry range)
LuMAV-3A Range, R (nmi) 0 5 10 15
175 % % 0 150 25 125 fuel 50 100 75 75 100 50 payload 125 25 150 0 % % 175 Useful Load, Wpl Load, (gmf)Useful 0 10203040
LuMAV-3A Endurance, E (min) Load, Wf (gmf) Fuel Useful UTRONIX corporation 9 Sept.’08 / pg # 61 OAVsOAVs onon thethe BattlefieldBattlefield
National and Theater Intelligence, Highly Survivable Surveillance Upper Tier – Target Acquisition, Cueing and Reconnaissance And Prosecution Systems Final ID before Authorization to Fire
Perimeter Surveillance - IR against Infantry
Answer Human request of Information! Pathfinder for Ground Vehicles Called by IUGS for Cross reference prior to waken Human Organic Air Vehicles Act As the Lower Tier - Local RSTA 9 SepSept.’08t.’08 / pg # 6262 Ducted Fan UAV Inboard Profiles
Electrical Subsystems Top Payload Engine Fan GPS Antenna Fuel Tank Fixed Stators Batteries Avionics and Electronics Payloads
Fuel Tanks Duct
Video CPU Collision GPS CPU Avoidance Landing Ring 4 Quadrant Vanes Antenna Memory Lower Payload Bay IR Camera Flight Computer
Servos
9 Sept.’08 / pg # 63 Flight Proven Autonomous 67” Fan Diameter Hover and low speed flight testing completed 31” OAV FCS VehiVehicleclele • Low costost manufacturingmanuufacturing 25” Fan Diameter • Commonmon componentscomponents FullyFu autonomous flight • Full autonomyutonomy FullFu flight speed regime 11.5” Fan Diameter Fully autonomous flight overer full flight speed regime, fieldd tested by Military in Hawaii 7” Fan Diameter Successful hover, low speed & high speed transition
LARGE
MEDIUM SMALL
9 Sept.’08 / pg # 64 Scalable Solution = family of vehicles MICRO ClassClass II
ARMY FCS • AVID Supports Honeywell in Contributing Aircraft Design and Analysis and Propeller Design and Analysis • AVID is part of a larger team for Honeywell including AAI, Locust, Techsburg AVID Tools and Expertise • AVID lead for aerodynamic design through PDR • AVID designing fan for performance and acoustics Status • Configuration CFD using TetRUSS • Concept design is underway and FUN3D • Wind tunnel testing to happen in first • Performance in AVID OAV months of 2008 • First flight in 2009 9 Sept.’08 / pg # 65