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Critical Design ReviewCritical Design Review

Tung TranMatt DrodofskyHaris Md IshakMatt Lossmann

Purdue UniversityPurdue UniversityAAE 451AAE 451Fall 2006Fall 2006Team FORETeam FORE

Mark KochRavi PatelKi-Bom KimAndrew Martin

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PresentationPresentation OverviewOverview

PropulsionPropulsionMotor SelectionMotor SelectionBattery SelectionBattery SelectionHigh Speed FlightHigh Speed Flight

Propeller PropertiesPropeller PropertiesMotor PropertiesMotor Properties

Endurance FlightEndurance FlightPropeller PropertiesPropeller PropertiesMotor PropertiesMotor Properties

Dynamics & ControlDynamics & ControlTail Surface SizingTail Surface SizingControl Surface SizingControl Surface SizingYaw Rate Control Feedback Yaw Rate Control Feedback systemsystem

Build ScheduleBuild ScheduleFlight TestFlight Test

Static TestStatic TestDynamic TestDynamic Test

Mission Requirements

AerodynamicsAspect and Taper Ratio

Wing Selection Analysis

StructuresLanding Gear

Weight DeterminationWeight Determination

List of ComponentsList of Components

Wing Tip Vertical Wing Tip Vertical DeflectionDeflection

Bending Moment StudyBending Moment Study

Skin and MaterialSkin and Material

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Mission RequirementsMission Requirements

High Speed Autonomous Unmanned High Speed Autonomous Unmanned AircraftAircraft

1 lb payload measuring 2.5x4x3 in1 lb payload measuring 2.5x4x3 in Takeoff and Landing Distance of 120 ftTakeoff and Landing Distance of 120 ft Minimum Climb Angle 35Minimum Climb Angle 35oo

Stall Velocity <= 30 ft/secStall Velocity <= 30 ft/sec Dutch Roll Damping > 0.8Dutch Roll Damping > 0.8 Budget Cost $250.00Budget Cost $250.00

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3 View Drawing3 View Drawing

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3-D Picture3-D Picture

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Aspect RatioAspect Ratio

Minimize Drag (Induced vs. Skin Friction)Minimize Drag (Induced vs. Skin Friction) Skin Friction DragSkin Friction Drag

Turbulent Flat Plate ApproximationTurbulent Flat Plate Approximation

Induced DragInduced Drag

58.210 Relog

455.0

l

fC

planform

wingwetfD S

SCC

f

eARk

ARe

1

64.0045.0178.1 68.0

LD kCCi

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Drag vs. Aspect RatioAt Various Flight Speed

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 2 4 6 8 10 12 14 16 18 20 22

Aspect Ratio

Drag

[lbf

]

V= 130 ft/s

V= 40 ft/s

AR=2.1

AR=17

Wing Aspect Ratio Optimization For High-Speed and Low-Speed Flight

1

1.2

1.4

1.6

1.8

2

2.2

0 2 4 6 8 10 12 14 16 18 20 22

Aspect Ratio

Drag

[ lbf

]AR=7

Aspect RatioAspect Ratio

Wing Span = 5.44 ft @ Wing Span = 5.44 ft @ AR = 7AR = 7

V = 49 ft/sV = 49 ft/s

V = 130 ft/sV = 130 ft/s

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Taper RatioTaper Ratio Best Taper Ratio: 0.45 (Best Taper Ratio: 0.45 (ellipticalelliptical = 0) [Anderson] = 0) [Anderson]

Induced DragInduced Drag

Fourier CoefficientsFourier Coefficients

SummationSummation

1.27% C1.27% CDiDi Increase v. Elliptical Lift Increase v. Elliptical Lift DistributionDistribution

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

Taper Ratio

Del

ta

AR=7

Min Taper = 0.449

N

ni

i

in

N

nin

i

nnAA

c

b

11 sin

sinsin

2

N

n

n

A

An

2

2

1

12

AR

CC L

Di

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Constraints:

Required CLmax at Vstall = 30 ft/s.

Reynolds Number ≈ 100,000

Source : UiUC Windtunnel Data

Martin Hepperle MH45Martin Hepperle MH32Selig/Donovan SD7032

CLmax required depends on

Wing Loading.

W/S = 1.29 [ lbf/ft2 ]

3-D CLmax = 1.21 [with flaps]

2-D CLmax = 1.09 [without flaps]

Reynolds Number ≈ 100,000Airfoil SelectionAirfoil Selection

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Martin Hepperle MH45Martin Hepperle MH32Selig/Donovan SD7032

Source : UiUC Windtunnel Data

Coefficient of Drag at Vdash = 130 ft/s:

Profile Coefficient of Drag

From Drag Polar

Coefficient of Induced Drag

Function of Coefficient of Lift

Minimum CDi Occurs at the lowest CL:

MH45 has lowest CL at minimum CD

Reynolds Number ≈ 300,000

Airfoil SelectionAirfoil Selection

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Tail SelectionTail Selection Airfoil Section Chosen to:Airfoil Section Chosen to:

Have low dragHave low drag ManufacturabilityManufacturability

Horizontal TailHorizontal Tail NACA 0009NACA 0009

Vertical TailVertical Tail NACA 0009NACA 0009

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Wing AnalysisWing Analysis MH45 Wing Analysis [Raymer & Brandt]MH45 Wing Analysis [Raymer & Brandt]

Conversion between 2-D and 3-DConversion between 2-D and 3-D2-D 2-D

Re Re 100,000100,000

2-D 2-D

Re Re 485,000485,000

3-D 3-D

Re Re 100,000100,000

3-D 3-D

Re Re 485,000485,000

UnitsUnits

5.6155.615 6.2046.20411

4.2574.25744

4.6434.64322

1/1/radrad

0.2050.20555

0.0900.09044

0.1850.18500

0.0840.08411

----

1.1211.121 ---- 1.0081.00899

---- ----

12.3612.36 ---- 13.3613.36 ---- degdeg

1.41.4 ---- 1.2151.21533

---- ----

8.368.36 ---- 1010 ---- degdeg

LCeAR

C

CC

l

lL

1

0LC

maxLC

00

9.0 lL CC

maxmax

9.0 lL CC

max oo 5.11max

flappedLCmax,

flappedmax,

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Flap AnalysisFlap Analysis 2-D Analysis in XFOIL2-D Analysis in XFOIL

3535o Deflection (0.15c) Deflection (0.15c)

Convert to 3-D Convert to 3-D [Raymer][Raymer]

o

lC

4

419.0

max

max

..

.2max,max,max,

.

cos

cos9.0maxmax

lh

f

lhf

Dcleanflapped

lhf

lL

S

SS

SS

SCC

flapped area over wing area

angle of hinge line to center line

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Landing Gear AnalysisLanding Gear Analysis

Assumptions: [Raymer]Assumptions: [Raymer] Main Landing Wheels support 90% of Main Landing Wheels support 90% of

weights.weights. Taildragger aft tires are about a quarter Taildragger aft tires are about a quarter

to a third the size of the main tires. to a third the size of the main tires. Tire sizing:Tire sizing:

Diameter : 0.1633ft (1.96 in)Diameter : 0.1633ft (1.96 in) Width: 0.075ft (0.9 in)Width: 0.075ft (0.9 in)

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Longitudinal tip-over analysis Longitudinal tip-over analysis [Raymer][Raymer]

Angles between most aft/most forward CG and main landing gear should be between 16 to 25 degrees.

The tail-down angle should be between 10 to 15 degrees

Lateral tip over analysis

Main wheels should be more than 25 degrees laterally from Center of Gravity.

Tip-over AnalysisTip-over Analysis

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Wing AssemblyWing Assembly

Wing Mount

Complete wing assembly with fiberglass cover

Leading Leading EdgeEdge

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Skin Materials Trade Skin Materials Trade StudyStudy

 Balsa

WoodFiber

GlassUnits

 

Shear Modulus 23600 1000000 psi

Density 9.68 117.41 lbm/ft3

Required Skin Thickness 0.0684 0.00162 ft

Volume 0.2895 0.0068 ft3

Weight 2.8017 0.8037 lbs

Purpose: Compare weight of skin made of different materials

Method: Single cell Thin-walled analysis

Result: Fiber glass has lowest weight

t

dsq

GA2

1

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Skin & MaterialSkin & Material

GRP (Glass Reinforced plastic) wing GRP (Glass Reinforced plastic) wing covering (fiber glass w/ epoxy)covering (fiber glass w/ epoxy)

3oz E Glass Satin WeaveThickness: 0.0046“(Two layer 0.0092’’)

Epoxy hardener (205(fast) +206(slow))

Epoxy Resin (105)

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List of ComponentsList of Componentscomponent material weight (lb)

internal body balsawood 0.1444

main wing foam + fiber glass 1.2750

vertical wing foam + fiber glass 0.0946

horizontal stabilizer foam + fiber glass 0.2214

fuselage foam 0.1935

wing Mount balsawood + foam 0.0181

nose cap fiber glass 0.0773

motor (w/ gear box) 0.8000

gyro 0.0400

servo (rudder,elevator,flaperon) 0.3791

receiver 0.0397

speed control 0.1000

battery 0.5000

landing gear 0.1243

payload 1.0000

total (including battery payload) 5.0074

(excluding battery and payload) 3.5074

Total Weight:

5.0074 lb

(excluding control wires, hinges and glue)

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CG DeterminationCG Determination Center of gravity:Center of gravity:

m

m

dm

xdmx

m

m

dm

zdmy

Center of gravity

Moment of inertia (results from CATIA)

GGxx (in) (in) GGyy (in) (in) GGzz (in) (in)

11.8311.83 1.231.23 00

IIxx (slug*ft(slug*ft22)) IIyy IIzz IIxyxy IIxzxz IIyzyz

0.1340.134 0.3130.313 0.1850.185 -0.005-0.005 -1.731e-5-1.731e-5 -1.613e-5-1.613e-5

XX

YY

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Bending Moment StudyBending Moment Study

(psi) 210000

glassfiber

ofstrength Tensile

)199070(psi x

x I

My

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Wing Tip Vertical Wing Tip Vertical DeflectionDeflection

Vertical deflection of wing tip

0.1167ft (1.4in)

EI

Mxx

2)(

2

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Catia ModelCatia Model

BenefitsBenefits VisualizationVisualization Moment of InertiaMoment of Inertia CG CalculationCG Calculation Weight EstimationWeight Estimation CNC ManufacturingCNC Manufacturing

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Battery SelectionBattery Selection A123 Racing Lithium A123 Racing Lithium

Ion batteriesIon batteries 5 cells5 cells 70A continuous 70A continuous

dischargedischarge 2300mAh per cell2300mAh per cell 3.6 V per cell3.6 V per cell 70 grams per cell70 grams per cell

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Motor SelectionMotor Selection

Motor InformationMotor Information AXI 2826/10 Gold lineAXI 2826/10 Gold line

3-5 lipo cells3-5 lipo cells Kv - 920 RPM/VKv - 920 RPM/V Max Continuous – 30AMax Continuous – 30A Max Burst – 42AMax Burst – 42A Acceptable Props: Acceptable Props:

10x8-13x1010x8-13x10

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High Speed MissionHigh Speed Mission

Propeller PropertiesPropeller Properties 10 in propeller10 in propeller 8 in pitch8 in pitch Advance Ratio - .73Advance Ratio - .73 Propeller Efficiency - .85Propeller Efficiency - .85 Cp - .0404Cp - .0404 Ct - .0468Ct - .0468 RPM – 12909rpmRPM – 12909rpm Output Power – 327.3 Output Power – 327.3 ft-ft-

lbf/seclbf/sec

High Speed = 130 High Speed = 130 ft/secft/sec

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High Speed MissionHigh Speed Mission

Motor PropertiesMotor Properties Power Out – 525 wattsPower Out – 525 watts Input Current – 39.1AInput Current – 39.1A Input Voltage – 14.2VInput Voltage – 14.2V RPM – 12908rpmRPM – 12908rpm Motor efficiency - .95Motor efficiency - .95

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Endurance MissionEndurance Mission

Fly Fly endurance endurance mission at mission at 49ft/s49ft/s

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Endurance MissionEndurance Mission Propeller Propeller

PropertiesProperties 12 in diameter12 in diameter 8 in pitch8 in pitch Advance Ratio - .67Advance Ratio - .67 Propeller Efficiency Propeller Efficiency

- .85- .85 Cp - .03Cp - .03 Ct - .037Ct - .037 RPM – 4385rpmRPM – 4385rpm Output Power – 23.2 Output Power – 23.2 ft-ft-

lbf/seclbf/sec

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Endurance MissionEndurance Mission Motor PropertiesMotor Properties

Power Out – 36 wattsPower Out – 36 watts Input Current – 9.3AInput Current – 9.3A Input Voltage – 4.8VInput Voltage – 4.8V RPM – 4385rpmRPM – 4385rpm Motor efficiency - .81Motor efficiency - .81 51 min flight time51 min flight time

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Class II Sizing of Tail Area (Horizontal & Vertical Surfaces)

MAC = 0.815 ft (9.78 in)

CG Range = 0.184MAC – 0.327MAC

CG Location = 0.235MAC

AC Location = 0.4153MAC

Static Margin = 18%

Static Margin Range = 14 %

0 0.5 1 1.50

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1Static Margin based on Horizontal Tail Area

Horizontal Tail Area [ft2]

xbar

ac A

and

xba

r cg af

t []

Xcgaft

XacA

Sh = 1.0 ft2

Longitudinal Static Stability Longitudinal Static Stability CCmmαα

=-1.6265 rad=-1.6265 rad-1-1

Usually negativeUsually negativeSv = 0.4 ft2

Weathercock StabilityWeathercock Stability CCnnββ

=0.10193 rad=0.10193 rad-1-1

typically 0.06 to 0.2typically 0.06 to 0.2RoskamRoskam

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SummarySummary

  Wing Horizontal Tail Vertical Tail Units

AR 7 4 2.3 []

Taper Ratio 0.45 0.72 0.6 []

Area 4.23 1 0.4 [ft2]

Span 5.44 2 0.9583 [ft]

MAC 0.815 0.5 0.54167 [ft]

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Control SurfacesControl Surfaces

eLhLLLLehi

CiCCCC

0 emhmL

L

mm

ehiCiCC

dC

dCC 00

Trim Diagram [Roskam]Trim Diagram [Roskam]Horizontal Stabilizer Incidence Angle = -1Horizontal Stabilizer Incidence Angle = -1oo

Max Trim Elevator Deflection Angle = -15Max Trim Elevator Deflection Angle = -15oo

High Speed CHigh Speed CLL = 0.08 = 0.08Flaperon 

Span 3 ft

Chord 0.16667 ft

η_ia 0.35Spanw  ft

η _oa 0.9Spanw  ft

Elevator

Span 2 ft

Chord 0.1 ft

 Rudder

η_v_ir 0.2083Spanv ft

η_v_or 0.9583Spanv ft

Chord 0.375 ft

Historical Data: Cessna Skywagon

Pitch, elevator sizePitch, elevator size CCmmδδee

=-2.6408=-2.6408

typically -1 to -2typically -1 to -2Yaw and/or roll, Yaw and/or roll, rudder sizerudder size CCnnδδrr

=-0.1002=-0.1002

typically -0.06 to -typically -0.06 to -0.120.12Roll, flaperon sizeRoll, flaperon size CCllδδaa

=0.285=0.285

typically 0.05 to typically 0.05 to 0.20.2

o10max

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Modal ParametersModal ParametersOpen LoopOpen Loop

Phugoid modePhugoid mode Damping Ratio: 0.495Damping Ratio: 0.495 Natural Frequency: 0.2582 Natural Frequency: 0.2582 radrad//secsec

Short Period modeShort Period mode Damping Ratio: 0.934Damping Ratio: 0.934 Natural Frequency: 13.248 Natural Frequency: 13.248 radrad//secsec

Dutch Roll modeDutch Roll mode Damping Ratio: 0.2014Damping Ratio: 0.2014 Natural Frequency: 8.355 Natural Frequency: 8.355 radrad//secsec

Roll modeRoll mode Time Constant: 0.49 secTime Constant: 0.49 sec

Spiral modeSpiral mode Time Constant: 54.91 secTime Constant: 54.91 sec

OgataOgata

n

22dn j

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Dutch Roll Feedback Block Dutch Roll Feedback Block DiagramDiagram Nominal Gain: -0.11Nominal Gain: -0.11

Dutch Roll closed loopDutch Roll closed loop Damping Ratio: 0.841Damping Ratio: 0.841 Natural Frequency: 10.9 Natural Frequency: 10.9

radrad//secsec

Aircraft and Servo Transfer Function

950 + s 40 + s^2

950

)950402^)(79.69368.32^)(07673.0)(369.8(

)161.14425.02^)(355.8(69673

ssssss

sss

)81.69367.32^)(07672.0)(366.8(

)161.14426.02^)(354.8(3431.73

ssss

sssAircraft Transfer FunctionServo Transfer Function

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Root Locus of Control Root Locus of Control SystemSystem

Closed Loop Poles for Yaw Rate feedback to RudderClosed Loop Poles for Yaw Rate feedback to Rudder

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Build ScheduleBuild Schedule

38

Flightline TestsFlightline TestsStatic TestStatic Test (Purdue Airport)(Purdue Airport)

Rate Gyro Gain setting – Correct DeflectionRate Gyro Gain setting – Correct DeflectionTransmitter Receiver operationTransmitter Receiver operationControl Surface operationControl Surface operationPropulsion operationPropulsion operation

Dynamic TestDynamic Test (McAllister Park)(McAllister Park)Taxi Run – Landing Gear and Tail Wheel controllabilityTaxi Run – Landing Gear and Tail Wheel controllabilityRate Gyro Gain setting – Correct MagnitudeRate Gyro Gain setting – Correct MagnitudeFirst flight: (Yaw feedback control off)First flight: (Yaw feedback control off)

Brief liftoff and land to feel initial handing qualities of aircraftBrief liftoff and land to feel initial handing qualities of aircraftSecond flight:Second flight:

Sustaining flight with turns to evaluate aircraft stability and Sustaining flight with turns to evaluate aircraft stability and controlcontrol

Third flight:Third flight:Go through procedures to set rate gyro gain.Go through procedures to set rate gyro gain.

FULL THROTTLE FLIGHT!FULL THROTTLE FLIGHT!

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ReferencesReferences

Brandt, Steven. Et al. Introduction to Aeronautics: Brandt, Steven. Et al. Introduction to Aeronautics: A Design Perspective. 1997.A Design Perspective. 1997.

Raymer, D. Aircraft Design: A Conceptual Raymer, D. Aircraft Design: A Conceptual Approach. Forth Edition. 2006.Approach. Forth Edition. 2006.

Stevens, B., Lewis, F. Aircraft Control and Stevens, B., Lewis, F. Aircraft Control and Simulation. 2003.Simulation. 2003.

Anderson, J. Fundamentals of Aerodynamics. 2001.Anderson, J. Fundamentals of Aerodynamics. 2001. Callister, W. D. Material Science & Engineering 2nd

edition. 2005. Sun, C. T. Mechanics of Aircraft Structures. 1998.Sun, C. T. Mechanics of Aircraft Structures. 1998.

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Questions?Questions?