Team 5Critical Design Review

Trent Lobdell Ross May Maria MullinsChristian Naylor Eamonn Needler Charles ReyzerJames Roesch Charles Stangle Nick White

AAE 451 – Team 5March 24, 2005 2

Outline Mission Requirements Team Design Aerodynamics Dynamics & Control Propulsion Structures / Landing Gear Prediction of Vehicle Performance Remaining Design Problems

AAE 451 – Team 5March 24, 2005 3

Requirements Design Requirements & Objectives

Take-Off and landing distance: 100 ft* Take-Off with minimum climb angle: 20° Endurance: 15 min* Typical descent angle of: 5.5° Stall Speed: 20 ft/s Loiter Speed: 28 ft/s* Minimum Turn speed: 23.33 ft/s* Turn Radius: 35 ft* Operating Altitude: 18 ft* Operational Airspace: 360x150 ft

*Changed Requirements from Mission Specification

AAE 451 – Team 5March 24, 2005 4

Design Features

Features / Unique AspectsStealth ThemeTwin BoomsPusher PropMulti-Sweep

WingPredicted Weight: 0.84 lbf

AAE 451 – Team 5March 24, 2005 5

Design PropertiesProperty Value UnitsWing Area 2.55 ft 2̂Wing Span 3.24 ftRoot Chord 1.11 ftTip Chord 0.33 ftMean Chord 0.72 ftInner LE Sweep 37.00 degOuter LE Sweep 20.00 degC/4 Sweep 13.63 degOuter TE Sweep 6.00 degInner TE Sweep 14.00 degAspect Ratio 4.11Taper Ratio 0.30

Property Value UnitsDiameter 0.20 ft

Property Value UnitsSpan 0.58 ftArea 0.24 ft^2Chord 0.41 ftAspect Ratio 1.42

Wing

Property Value UnitsAreas 0.22 ft^2Height 0.35 ftRoot Chord 0.41 ftTip Chord 0.21 ftAspect Ratio 1.14Taper Ratio 0.50

Property Value UnitsLength 2.11 ftWidth 3.24 ftHeight 0.69 ftBoom Sep. 0.58 ft

Fuselage

Horizontal Tail

Vertical Tail

Overall Aircraft

AAE 451 – Team 5March 24, 2005 6

Design - Dimensions

AAE 451 – Team 5March 24, 2005 7

Aerodynamics - Airfoils Low Re Number

91903 (Stall) - 128660 (Cruise)

Wing Eppler E212

Tail Eppler E169 Horizontal Tail

NACA 0010

Vertical Tail

0 0.2 0.4 0.6 0.8 1

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

e169

0 0.2 0.4 0.6 0.8 1

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

e212

0 0.2 0.4 0.6 0.8 1-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

x/c

y/c

Airfoil Geometry

NASG: http://www.nasg.com/afdb/search-airfoil-e.phtmlUIUC: http://www.aae.uiuc.edu/m-selig/ads/coord_database.html

AAE 451 – Team 5March 24, 2005 8

Aerodynamics – Geometry Defined Sweep Angles (Λ) Defined taper ratio (λ) of 1st segment Defined Span Ratio of 2 segments Adjust to balance

StyleAspect RatioTip Chord feasibility

AAE 451 – Team 5March 24, 2005 9

Aerodynamics - Lift

0

2

0 0

cos

1 cos / cos /

aa

a AR a AR

-5 0 5 10 15 20-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

2D Lift Curve

Cl

CL

3D Lift Curve

CLmax

Hembold

CLmax

Estimate

Lift Coefficients vs. α

α (deg)

CL a

nd

Cl

CLmax (Hembold): 0.74Max Lift (Hembold): 1.10 lbf

Sweep Corrected Hembold Equation1

1 Anderson, J.D., Fundamentals of Aerodynamics, New York, 2001, pp 351-416

/ 2

/ 2

2( )

b

L

b

C y dyV S

Prandtl Lifting Line Theory1

AAE 451 – Team 5March 24, 2005 10

Aerodynamics - Drag

Parasite Drag Buildup#

1

i i

p

compi i f wet

Di ref

K QC SC

S

Sref = reference area [ft2]Cf = skin friction coefficientK = form factorQ = interference factor

Component CDp

Wing: 0.017Fuselage: 0.005Horiz. Tail: 0.015Vert. Tails: 0.004Booms: 0.011Wheels: 0.027Struts: 0.0003Misc: 0.004CDp: 0.083

Total Drag:CDp: 0.083CDi: 0.029CDtot: 0.112Drag: 0.4473 lbf

AAE 451 – Team 5March 24, 2005 11

Aerodynamics – L/D

L/Dmax=13.21 Loiter at

α=.71°,4.46° Loiter at

0.866*L/Dmax2

Wing Incidence: 3° Tail Incidence: -7.3° α (deg)

L/ D

L/D vs. α

-5 0 5 10 15 20-10

-5

0

5

10

15

L/D

Loiter Requirement

2 Raymer, D.P., Aircraft Design: A Conceptual Approach, Virginia, 1999, pp 27

-5 0 5 10 15 20-4

-2

0

2

4

6

8

10

L/D

Trim

L/D=4.7

AAE 451 – Team 5March 24, 2005 12

Class 2 Tail Sizing (X-plot)

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10.8

0.9

1

1.1

1.2

1.3

1.4

1.5X-Plot for Horizontal Tail

Tail Area [sq ft]

Loca

tion

(nor

mac

lized

abo

ut C

MA

C)

xcg

xN

xacw

Desired SM

AAE 451 – Team 5March 24, 2005 13

Trim Diagram

0 0.2 0.4 0.6 0.8 1 1.2-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

Trim Diagram for Cf/C = 0.5

CLtotal

Cm

cg

e

0

3

6

9 12

-30

30

0

-10

10

AAE 451 – Team 5March 24, 2005 14

Control Surface Sizing Aileron size / dimension:

Area:0.04 ft2 Length: 0.63 ft Root Chord: 0.08 ft Tip Chord: 0.05 ft

Elevator size / dimension: Area: 0.10 ft2 Span: 0.50 ft Chord: 0.21 ft

Rudder size / dimension: Area: 0.02 ft2

Base 1: 0.04 ft Base 2: 0.15 ft Height: 0.19 ft

AAE 451 – Team 5March 24, 2005 15

Class 2 Vertical Tail Sizing (X-plot)

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-4

-2

0

2

4

6

8

10

12

14x 10

-3 Yawing Moment Coeff. Variation with Side Slip Angle vs. Vertical Tail AreaC

n

Sv [ft2]

0.001|

|

|

|

|

Cn vs. S

v for our aircraft's dimensions

Desired Cn

0.218 ft2

AAE 451 – Team 5March 24, 2005 16

Feedback ControllerPitch Rate Feedback to Elevator

1Gyro RatePitch

1ServoElevator

AAE 451 – Team 5March 24, 2005 17

Feedback Controller

Damping Ratio w/o Feedback = 0.74

Desired Damping Ratio = 0.35 – 1.3

We chose a Damping Ratio = 0.95

Feedback Gain Required = 0.07

AAE 451 – Team 5March 24, 2005 18

Propeller Take-Off Characteristics

Type 2-Bladed 3-Bladed

Propeller Diameter 6 in 5 in

Pitch 4 in 3 in

Operating RPM 14300 RPM 16400 RPM

Efficiency 0.61 0.60

AAE 451 – Team 5March 24, 2005 19

Propeller Plots – 6 inch prop

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.80

0.05

0.1

Thr

ust

Coe

f, C

T

Data for hypothetical propeller with tau= 0.66667

CT*= 0.024906 for J*= 0.76

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.80

0.02

0.04

0.06

Pow

er C

oef,

CP

CP*= 0.022677 for J*= 0.76

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.80

0.5

1E

ffic

ienc

y, e

ta

Advace ratio, J=V/(nD)

Eta*= 0.83468 for J*= 0.76

X is the selected operating point

0 0.05 0.1 0.15 0.2 0.25 0.3 0.350

0.1

0.2

Thr

ust

Coe

f, C

T

Data for hypothetical propeller with tau= 0.66667

CT*= 0.076352 for J*= 0.33566

0 0.05 0.1 0.15 0.2 0.25 0.3 0.350

0.02

0.04

0.06

Pow

er C

oef,

CP

CP*= 0.042285 for J*= 0.33566

0 0.05 0.1 0.15 0.2 0.25 0.3 0.350

0.5

1

Eff

icie

ncy,

eta

Advace ratio, J=V/(nD)

Eta*= 0.60609 for J*= 0.33566

X is the selected operating point

Take-Off Loiter

CT = 0.076

CP = 0.042

η = .61

CT = 0.025

CP = 0.023

η = .83

AAE 451 – Team 5March 24, 2005 20

Motor Selection - Graupner Speed 400 6V(Direct Drive) Characteristics

Engine Characteristics Propeller Shaft Diameter 0.091 in

Engine Diameter 1.08 in

Engine Length 1.5 in

Weight 2.55 oz

Rated Horsepower 0.12 hp

Rated Loaded RPM 15500 RPM

Operating Conditions Operating RPM (Take Off) 14300 RPM

Input Voltage 8.34 Volts

Input Current 11.7 Amps

Output Power 0.078 hp

AAE 451 – Team 5March 24, 2005 21

Battery & Speed Controller Selection Thunder Power 3 Cell Li-Po

Rated for 12-15 Amps 2100 mAh

Allows for extended endurance as specified in the DR&O

4.6 oz.

JETI 12 Amp Microprocessor Motor Controller For 2-3 Cell LiPo Weight = 0.53 oz. 1x0.75x0.3 in.

AAE 451 – Team 5March 24, 2005 22

Landing Gear

Main gear (2) Single beam, t = 0.0017 ft Stroke = 0.0458 ft Weight = 0.0018 lbf 30° angle for lateral stability 20° in front of CG for

longitudinal stability Absorb impact

Gear deform instead of break Easy to change

Tail Gear (2) 18 gauge steel wire Prevent prop and tail strike

Gear deform instead of break

•Parameters•θ = 30°•Material = Al•Ngear = 3 (Gen. Av.)

3

sin3

FlS

EI

AAE 451 – Team 5March 24, 2005 23

Structures - CGWeight (lbf) Location (ft)

Motor 0.158 1.208Speed Control 0.063 0.104Batteries 0.188 0.083Gear Struts 0.003 0.500Wing 0.127 0.360H-Tail 0.017 1.860V-Tail 0.010 1.841Booms 0.065 1.057Wheels 0.025 0.334Radio 0.040 0.104Gyro 0.053 0.042Wing Servos 0.040 0.279H-Tail Servo 0.020 1.860V-Tail Servo 0.020 1.841Prop 0.060 1.214Attachment mat. 0.006

CGTOTAL 0.865 0.616

CG (ft) 0.616CG (%) 0.860xAC (ft) 0.720xAC (%) 1.004

Static Margin (%) 0.145

AAE 451 – Team 5March 24, 2005 24

Structures - Load Analysis

Structural loads from code – basic equations usedτ max = 2.40 lbf/ft2

Mroot = 0.26 ft-lbfσmax = 0.0048 lbf/ft2

Deflectionsδy = 9.1e-11 ftδΦ = 1.1e-4 degrees

AAE 451 – Team 5March 24, 2005 25

Structures - Load Analysis

Torsion Loads T = 0.1 ft-lbf. at high

maneuver

Failure of wing (most likely due to buckling) occurs at ncr = 38 or at σcr = 32 psf.

AAE 451 – Team 5March 24, 2005 26

Scheduled Tests

Drop Test Height of 2.5 ft Tests landing gear and crash survivability

Wing Load Test Test maximum load of wing

Flight Test Propeller test Feedback gain test Control surface test

AAE 451 – Team 5March 24, 2005 27

Strength Testing

Failure at 26 lbf

AAE 451 – Team 5March 24, 2005 28

Strength Testing

Failure due to bucklingPounds Tip Deflection (ft)

0.88 0.00091.76 0.00762.65 0.01486.00 0.0228

12.00 0.045226.00 BROKEN

AAE 451 – Team 5March 24, 2005 29

Manufacturing

Wing/fuselage and tails milled using CNC Wet lay-up with 0.6 oz. bidirectional s-glass Holes cut and tapped for component

placement Epoxy bonding of tails and booms Mechanical attachment of landing gear,

motor, etc.

AAE 451 – Team 5March 24, 2005 30

Manufacturing - Booms

Circular holes cut for boom insertion Foam is bonded inside and out to tube Boom pinned into place with wire

AAE 451 – Team 5March 24, 2005 31

Overall Schedule

To be accomplished before 1st flightOrder parts – March 10Build prototype wing – March 11Test prototype strength – March 22

CDR – March 24 CNC Parts – by March 28 Fiberglass Parts – by April 3 Build – by April 7 Test and modify – until flight date

AAE 451 – Team 5March 24, 2005 32

Predicted Flight Performance

Max. Turning Radius: 35 ft (DR&O) Bank Angle: 34.82° Turn Rate: 0.8 rad/s

Min. Turning Radius: 10.92 ft (Limit) Bank Angle: 65.85° Turn Rate: 2.57 rad/s

Maximum Climb Angle: 26.77° Take-Off Distance: 16.29 ft Landing Distance: 22.48 ft

AAE 451 – Team 5March 24, 2005 33

Current Issues

Propeller air flow Engine heating Manufacturability

Boom attachmentsCG movement