UCSD/General Atomics Design UCSD/General Atomics Design Project:Project:

Aeroelastic Wing EnhancementAeroelastic Wing Enhancement

Jose Panza, Project SponsorJose Panza, Project Sponsor Dr. James D. Lang, Project AdvisorDr. James D. Lang, Project Advisor Jonquil Urdaz, Team LeaderJonquil Urdaz, Team Leader Sean SummersSean Summers Steve RingelSteve Ringel Jorge MendozaJorge Mendoza

Presentation Outline:Presentation Outline: Goals, Schedule, & Actual CostGoals, Schedule, & Actual Cost Active Camber ChangeActive Camber Change

– Aircraft CharacteristicsAircraft Characteristics– Aircraft Initial PerformanceAircraft Initial Performance– Methods of Altering AirfoilMethods of Altering Airfoil– Effects of Altering AirfoilEffects of Altering Airfoil– Final PerformanceFinal Performance– PropulsionPropulsion

Control ReversalControl Reversal– Stability & ControlStability & Control– Materials & StructureMaterials & Structure

Cost EstimatesCost Estimates ConclusionsConclusions References & AcknowledgementsReferences & Acknowledgements

Goals:Goals: Originally: Create flutter suppressant Originally: Create flutter suppressant

designdesign After research and advice from After research and advice from

Professors-new goalProfessors-new goal New Goals: New Goals: Increase performance Increase performance

and roll efficiency with active camber and roll efficiency with active camber change and control reversalchange and control reversal

Schedule:Schedule:

Flutter research (3 weeks)Flutter research (3 weeks) Thunder and control reversal Thunder and control reversal

research (3 weeks)research (3 weeks) Analysis and data collection (2 Analysis and data collection (2

weeks)weeks) Finalize analysis, conclusions, and Finalize analysis, conclusions, and

presentation preparation (2 weeks)presentation preparation (2 weeks)

Current CostCurrent Cost

Engineering Engineering hours and hours and transportation transportation costscosts

Total current Total current cost $37,863.00cost $37,863.00

Engineering Cost

05000

10000150002000025000300003500040000

1 2 3 4 5 6 7 8 9 10 11

Weeks

Cost (US Dollars)

Series1

Active Camber Change:Active Camber Change:Original Airfoil Positively Deflected Airfoil

Negatively Deflected Airfoil

Aircraft Characteristics:Aircraft Characteristics:

TOGW = 10,500 lbsTOGW = 10,500 lbs T/W = 0.14T/W = 0.14 W/S = 33.33W/S = 33.33 Span = 84 feetSpan = 84 feet Sweep = 2.36 degreesSweep = 2.36 degrees

Aircraft Initial Performance:Aircraft Initial Performance:

Max Air Speed = 220 knotsMax Air Speed = 220 knots Cruise Velocity = 144 knotsCruise Velocity = 144 knots Loiter = 127 knotsLoiter = 127 knots

Cruise Out

4,000 nm

Loiter

38 hours

Cruise Back25, 000 feet

52,000 feet

3,900 nm

Aircraft Initial Performance:Aircraft Initial Performance:Parasite Drag Buildup

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 0.2 0.4 0.6 0.8 1 1.2

Mach Number

CDo

SL

25K

52K

60K

66K

Area Ruling

0

10

20

30

40

50

60

0 5 10 15 20 25 30 35 40

Longitudinal Distance (ft)

Cross Sectional Area (ft^2)

Methods of Altering Airfoil:Methods of Altering Airfoil:

Less power required to actively Less power required to actively change camberchange camber

CompactCompact Easy to InstallEasy to Install Alternative = Spar TwistingAlternative = Spar Twisting

Thunder-Piezoelectric Actuator

Airfoils: TipAirfoils: Tip

Tip Airfoil FX67-K-150/17

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0 0.2 0.4 0.6 0.8 1

Upper Surface Airfoil

Lower Surface Airfoil

Camber Line

Max Deflection 150/17 Airfoil

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0 0.2 0.4 0.6 0.8 1

Upper Surface

Lower Surface

Camber

Neg Deflection 150/17

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0 0.2 0.4 0.6 0.8 1

Upper Surface

Lower Surface

Camber

Original Airfoil Positively Deflected Airfoil

Negatively Deflected AirfoilMax thickness:

t/c = 0.15

Camber = 0.05

@40%chord

Max thickness:

t/c = 0.16

Camber = 0.06

@43%chord

Max thickness:

t/c = 0.14

Camber = 0.04

@34%chord

Airfoils: RootAirfoils: RootOriginal Airfoil Positively Deflected Airfoil

Negatively Deflected Airfoil

Root Airfoil FX67-K-170/17

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0 0.2 0.4 0.6 0.8 1

Upper Surface Airoil

Lower Surface Airfoil

Camber Line

Neg Deflection 170/17

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0 0.2 0.4 0.6 0.8 1

Upper Surface

Lower Surface

Camber

Max Deflection Airfoil

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0 0.2 0.4 0.6 0.8 1

Upper Surface

Lower Surface

Camber

Max thickness:

t/c = 0.17

Camber = 0.05

@40%chord

Max thickness:

t/c = 0.19

Camber = 0.06

@47%chord

Max thickness:

t/c = 0.15

Camber = 0.04

@34%chord

Effects of Altering Airfoil:Effects of Altering Airfoil:Theoretical Lift Coefficient vs Angle of Theoretical Lift Coefficient vs Angle of

AttackAttack

-0.3

-0.1

0.1

0.3

0.5

0.7

0.9

1.1

1.3

1.5

-8 -6 -4 -2 0 2 4 6 8 10

Angle of Attack

CL

Theoretical clRoot Airfoil

Theoretical clTip Airfoil

PositiveDeflectedRoot Airfoil

PositiveDeflected TipAirfoil

NegativeDeflectedRoot Airfoil

NegativeDeflected TipAirfoil

Effects of Altering Airfoils:Effects of Altering Airfoils:CD0 vs Mach NumberCD0 vs Mach Number

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Mach Number

CDo Undeflected

Positive Deflection

Negative Deflection

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Mach Number

CDo

Undeflected

PositiveDeflection

NegativeDeflection

At 25,000 feet At 52,000 feet

Effects of Altering Airfoil:Effects of Altering Airfoil:K vs Mach NumberK vs Mach Number

0

0.005

0.01

0.015

0.02

0.025

0.03

0 0.2 0.4 0.6 0.8 1 1.2

Mach Number

K Undeflected

Positive Deflection

Negative Deflection

0

0.005

0.01

0.015

0.02

0.025

0.03

0 0.2 0.4 0.6 0.8 1 1.2

Mach Number

KUndeflected

Positive Deflection

Negative Deflection

At 25,000 feet At 52,000 feet

Effects of Altering Airfoil:Effects of Altering Airfoil:

-1

-0.5

0

0.5

1

1.5

2

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07

CD

CL

Loiter 52K Undeflected

Loiter 52K PosDeflected

Loiter 52K NegDeflected

-1

-0.5

0

0.5

1

1.5

2

0 0.01 0.02 0.03 0.04 0.05 0.06

CD

CL

Undeflected

Positive Deflection

Negative Deflection

Drag Polar Drag Polar 52,000feet - 52,000feet - Loiter SpeedLoiter Speed

Drag Polar Drag Polar 25,000feet-25,000feet-Cruise SpeedCruise Speed

Effects of Altering Airfoils:Effects of Altering Airfoils:

0

10

20

30

40

50

60

70

80

0 0.1 0.2 0.3 0.4 0.5 0.6

CL

L/D

CL vs L/D

Pos Deflection

Neg Deflection

CL vs L/D at Cruise

0

10

20

30

40

50

60

70

80

90

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

CL

L/D

Undeflected

Positive Deflection

Negative Deflection

CL vs L/D at Loiter

Effects of Altering Airfoils:Effects of Altering Airfoils:Fuel Burned vs. DragFuel Burned vs. Drag

0

50

100

150

200

250

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Fuel Burned

Drag (lb) Undeflected

Positive Deflection

Negative Deflection

0

20

40

60

80

100

120

140

160

180

200

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Fuel Burned (lb)

Drag (lb)

Undeflected

PositiveDeflection

NegativeDeflection

At 25,000 feet At 52,000 feet

Final Performance:Final Performance:

Increased Performance:Increased Performance:– Loiter time = +1 hourLoiter time = +1 hour– Cruise Back = +400 nmCruise Back = +400 nm– Fuel = -200 lbs. to complete initial mission profileFuel = -200 lbs. to complete initial mission profile

Cruise Out

4,000 nm

Loiter

39 hours

Cruise Back

4,300 nm

25,000 feet

52,000 feet

Propulsion: Turboprop Engine Propulsion: Turboprop Engine

Based on Based on Assumptions from Assumptions from Raymer:Raymer:

Engine Characteristics Uninstalled

Actual Thrust 32,000

Scaled Thrust 1950

Actual Power 6500

Scaled Power 396

Scale Factor (SF) 0.060923077

Actual Weight 2600

Scaled Weight 274.8863387

Actual Length 16.66666667

Scaled Length 5.869111658

Actual Diameter 3.833333333

Scaled Diameter 2.739999005

Thrust vs. Mach Number

0

500

1000

1500

2000

2500

0 0.2 0.4 0.6

Mach Number

Thrust (lb)

SL

10K

20K

30K

40K

50K

60K

Control ReversalControl Reversal

Increasing Roll Effectiveness Utilizing Wing Increasing Roll Effectiveness Utilizing Wing Twist due to Control Surface ReversalTwist due to Control Surface Reversal

Stability and ControlStability and Control

Control reversalControl reversal Roll effectivenessRoll effectiveness Lateral control governed by control Lateral control governed by control

systemsystem Control surface sizingControl surface sizing Aerodynamic center Aerodynamic center Divergence speedDivergence speed Flutter speedFlutter speed

Control ReversalControl Reversal Actively control wing twist Actively control wing twist Increase roll-rate performanceIncrease roll-rate performance Damp out potential flutter excitationsDamp out potential flutter excitations Decrease deflection of wingDecrease deflection of wing Specific applications of AAW in recent Specific applications of AAW in recent

design studies have shown AAW design studies have shown AAW technology to provide a 7 to 10% technology to provide a 7 to 10% reduction in aircraft takeoff gross weight reduction in aircraft takeoff gross weight (TOGW) for subsonic cruise and Joint Strike (TOGW) for subsonic cruise and Joint Strike Fighter type configurations, while a 20% Fighter type configurations, while a 20% reduction can be realized in TOGW for a reduction can be realized in TOGW for a supersonic cruise configuration. supersonic cruise configuration.

Control Reversal:Control Reversal:

Negative Twist using Flaps and Ailerons

Positive Twist using Ailerons and Slats

Control Benefits/Issues of AAWControl Benefits/Issues of AAW If AAW works, then structural weight can be removed that If AAW works, then structural weight can be removed that

was otherwise needed to make the wing stiff. Also, the wing was otherwise needed to make the wing stiff. Also, the wing could have a higher aspect ratio, which would normally could have a higher aspect ratio, which would normally make it too flexible. Higher aspect ratio should reduce drag, make it too flexible. Higher aspect ratio should reduce drag, and combined with lower weight should improve payload-and combined with lower weight should improve payload-range performance. Boeing Sonic Cruiser officials have range performance. Boeing Sonic Cruiser officials have shown interest in the technique. shown interest in the technique.

The lurking concern is flutter. This is a reason the The lurking concern is flutter. This is a reason the preproduction F-18A design was chosen; its flight test preproduction F-18A design was chosen; its flight test showed that even though the wing was flexible, it did not showed that even though the wing was flexible, it did not have a flutter problem--hopefully removing this concern have a flutter problem--hopefully removing this concern from the AAW. There is no active flutter suppression in the from the AAW. There is no active flutter suppression in the planned AAW control laws. planned AAW control laws.

Roll PerformanceRoll Performance Less lateral moment of inertia of wing due to Less lateral moment of inertia of wing due to

lighter winglighter wing Twisting wings will allow better flow control over Twisting wings will allow better flow control over

wing surface thus generating more lift and wing surface thus generating more lift and reducing dragreducing drag

Creates a more efficient wing during Creates a more efficient wing during maneuveringmaneuvering

Decreases the parasitic drag caused by control Decreases the parasitic drag caused by control surfaces with rigid wingsurfaces with rigid wing

Uses traditional roll generation methods until Uses traditional roll generation methods until dynamic pressures are high enough to twist wing dynamic pressures are high enough to twist wing with control reversalwith control reversal

Above switch occurs in control law (future work)Above switch occurs in control law (future work)

Block DiagramBlock Diagram

Control Surface SizingControl Surface Sizing Must generate enough Must generate enough

torque to twist the torque to twist the wing as desiredwing as desired

Control surfaces will Control surfaces will be used to damp out be used to damp out excitations that could excitations that could lead to flutterlead to flutter

Leading edge and Leading edge and trailing edge devices trailing edge devices used in main part of used in main part of wingwing

Trailing edge surface Trailing edge surface only on wingtiponly on wingtip

Aerodynamic CenterAerodynamic Center

Aerodynamic center is reference Aerodynamic center is reference point for pitching moment point for pitching moment calculationscalculations

Flight conditions are always subsonic Flight conditions are always subsonic for Marinerfor Mariner

Aerodynamic center can be assumed Aerodynamic center can be assumed to be located at quarter-chord of to be located at quarter-chord of Mean Aerodynamic Chord.Mean Aerodynamic Chord.

Divergence SpeedDivergence Speed Designed new wing to have the same divergence Designed new wing to have the same divergence

speed as current design. speed as current design. Sea levelSea level Safety factor = 1.25Safety factor = 1.25

Current divergence Current divergence speedspeed

426 feet per second426 feet per second

New divergence New divergence speedspeed

370 feet per second370 feet per second

Flutter SpeedFlutter Speed

New design flutter New design flutter speed at sea level:speed at sea level:

370 ft/sec370 ft/sec

Materials and StructuresMaterials and Structures

Material Selection Material Selection

Sources and estimates of limit loadsSources and estimates of limit loads

Structural conceptStructural concept

Wing shear and bending moment Wing shear and bending moment diagram approximations diagram approximations

Ixx, Iyy, J Ixx, Iyy, J

Material SelectionMaterial Selection

Similar materials as Similar materials as current designcurrent design

95% of aircraft is 95% of aircraft is compositescomposites

Composite properties Composite properties Utilize bend-twist Utilize bend-twist

coupling with layupcoupling with layup General dimensions of General dimensions of

current design current design conservedconserved

Finite Element ModelFinite Element Model

Aerodynamic LoadsAerodynamic Loads

Loads/Boundary ConditionsLoads/Boundary Conditions Flat plate Aero modelingFlat plate Aero modeling

Structural propertiesStructural properties

Wing approximated Wing approximated as cantilevered as cantilevered beam with beam with constant cross-constant cross-sectional areasectional area

Moments of inertia Moments of inertia for airfoil cross for airfoil cross sectionsection

Torsional Stiffness Torsional Stiffness of Wingof Wing

Ixx =Ixx = .032 ft^4.032 ft^4

Iyy =Iyy = .637 ft^4.637 ft^4

J =J = .669 ft^4.669 ft^4

CurrentCurrent

GJ =GJ =

NewNew

GJ =GJ =

5,000,0005,000,000

3,698,4003,698,400

Limit LoadsLimit Loads

Maneuvering loadsManeuvering loads Gust loadsGust loads Control deflectionControl deflection Take-off and landing loadsTake-off and landing loads Power plant loadsPower plant loads Load factors approximately 3 to 4Load factors approximately 3 to 4

Shear & Bending Moment Shear & Bending Moment DiagramsDiagrams

Shear Diagram

0

1000

2000

3000

4000

5000

6000

0 10 20 30 40

Spanwise Position (ft)

Shear Load (lb)

Lift load approximated as point load acting Lift load approximated as point load acting at aerodynamic center of wing.at aerodynamic center of wing.

Bending Moment

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

100000

0 10 20 30 40

Spanwise Position (ft)

Bending Moment (lb-ft)

Structural GeometryStructural Geometry

SpanSpan MACMAC Spar locationsSpar locations Set up (spars skin) Set up (spars skin)

no ribs or stringersno ribs or stringers

SpanSpan 84 ft84 ft

MACMAC 4.04 ft4.04 ft

Main SparMain Spar 25% MAC25% MAC

Aft SparAft Spar 75% MAC75% MAC

LE SweepLE Sweep 2.36 deg2.36 deg

TE SweepTE Sweep 2.00 deg2.00 deg

Skin Skin ThicknessThickness

.25 in.25 in

Spar Spar ThicknessThickness

.5 in.5 in

Material Cost Material Cost

Cost of Thunder actuator per aircraft:Cost of Thunder actuator per aircraft:

$170,861.48$170,861.48

DAPCA IV ModelDAPCA IV Model

Estimated Flyaway and RDT&E costs per Estimated Flyaway and RDT&E costs per aircraft for a 100 aircraft buy.aircraft for a 100 aircraft buy.

RDT&E + Flyaway=RDT&E + Flyaway= $637,505489.66$637,505489.66

Price per aircraft = Price per aircraft = $6,375,058.50$6,375,058.50

System Configuration System Configuration ImprovementsImprovements

Iterate to find optimal skin thicknessIterate to find optimal skin thickness Determine optimal spar dimensions Determine optimal spar dimensions

and locationsand locations More improvements can be made More improvements can be made

after test results are considered and after test results are considered and analyzedanalyzed

Cost ImprovementCost Improvement

Wait for the technology to matureWait for the technology to mature Make a special contract with supplier Make a special contract with supplier

to purchase Thunder actuators at a to purchase Thunder actuators at a lower costlower cost

Lower drag will increase efficiency Lower drag will increase efficiency and lower operational costsand lower operational costs

Conclusions:Conclusions:

Results: Not worth the extra cost for Results: Not worth the extra cost for MarinerMariner

Would be more profitable for a Would be more profitable for a Hunter/KillerHunter/Killer

Planes today do not operate at max Planes today do not operate at max efficiency – with increased efficiency – with increased technology this design will become technology this design will become the more profitable method to the more profitable method to increase performanceincrease performance

Future Work Needed:Future Work Needed:

Active Camber Change:Active Camber Change:– Research into Angle of Attack vs. Research into Angle of Attack vs.

Laminar FlowLaminar Flow Control Reversal:Control Reversal:

– Finite Element Model and AnalysisFinite Element Model and Analysis– Test article fabricationTest article fabrication– Flight TestingFlight Testing– Active flutter suppression in the planned Active flutter suppression in the planned

AAW control laws.AAW control laws.

References & References & Acknowledgements:Acknowledgements:

Josh Adams Josh Adams Dr. John KosmatkaDr. John Kosmatka John MeisnerJohn Meisner Raymer, Daniel P., “Aircraft Design: A Raymer, Daniel P., “Aircraft Design: A

Conceptual Approach”Conceptual Approach” Anderson, “Fundamentals of Anderson, “Fundamentals of

Aerodynamics”Aerodynamics” NASA PaperNASA Paper AIAA PaperAIAA Paper Beer, Ferdinand P., “Mechanics of Beer, Ferdinand P., “Mechanics of

Materials” Materials”