Team 5
Critical Design Review
Trent Lobdell
Ross May
Christian Naylor Eamonn Needler
James Roesch Charles Stangle
Maria Mullins
Charles Reyzer
Nick White
Outline








Mission Requirements
Team Design
Aerodynamics
Dynamics & Control
Propulsion
Structures / Landing Gear
Prediction of Vehicle Performance
Remaining Design Problems
March 24, 2005
AAE 451 – Team 5
2
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
March 24, 2005
AAE 451 – Team 5
3
Design Features

Features /
Unique Aspects
 Stealth
Theme
 Twin Booms
 Pusher Prop
 Multi-Sweep
Wing
Predicted Weight: 0.84 lbf
March 24, 2005
AAE 451 – Team 5
4
Design Properties
Wing
Horizontal Tail
Property
Value
Wing Area
2.55
Wing Span
3.24
Root Chord
1.11
Tip Chord
0.33
Mean Chord
0.72
Inner LE Sweep
37.00
Outer LE Sweep
20.00
C/4 Sweep
13.63
Outer TE Sweep
6.00
Inner TE Sweep
14.00
Aspect Ratio
4.11
Taper Ratio
0.30
Units
ft^2
ft
ft
ft
ft
deg
deg
deg
deg
deg
Fuselage
Property
Diameter
Value
Units
0.20 ft
March 24, 2005
Property
Span
Area
Chord
Aspect Ratio
Value
0.58
0.24
0.41
1.42
Units
ft
ft^2
ft
Overall Aircraft
Property Value
Length
2.11
Width
3.24
Height
0.69
Boom Sep.
0.58
Vertical Tail
Property
Areas
Height
Root Chord
Tip Chord
Aspect Ratio
Taper Ratio
Value
0.22
0.35
0.41
0.21
1.14
0.50
AAE 451 – Team 5
Units
ft^2
ft
ft
ft
5
Units
ft
ft
ft
ft
Design - Dimensions
March 24, 2005
AAE 451 – Team 5
6
e212
Aerodynamics - Airfoils
0.4
Low Re Number
 91903

e169
0.2
0.4
Airfoil Geometry
0.1
0.3
0.5
Wing
 Eppler

0.3
(Stall) - 128660 (Cruise)
0
0.2
0.4
E212
-0.1
0.1
0.3
Tail
 Eppler
-0.2
0
0.2
E169
-0.3
-0.1
0.1
Horizontal Tail
 NACA 0010
y/c

-0.4
-0.2
0
0
0.2
0.4
0.6
0.8
1
0.8
1
-0.3
Vertical Tail
-0.1
-0.4
-0.2
NASG: http://www.nasg.com/afdb/search-airfoil-e.phtml
UIUC: http://www.aae.uiuc.edu/m-selig/ads/coord_database.html
0
0.2
0.4
0.6
-0.3
March 24, 2005
AAE 451 – Team 5
-0.4
7
Aerodynamics – Geometry
Defined Sweep Angles (Λ)
 Defined taper ratio (λ) of 1st segment
 Defined Span Ratio of 2 segments
 Adjust to balance

 Style
 Aspect
Ratio
 Tip Chord feasibility
March 24, 2005
AAE 451 – Team 5
8
Aerodynamics - Lift
Sweep Corrected Hembold Equation1
a
Lift Coefficients vs. α
a0 cos 
1.4
1   a0 cos   /  AR     a0 cos  /  AR  
1.2
2
1
Prandtl Lifting Line
b/2
CL 
2
( y )dy

V S b / 2
CLmax (Hembold): 0.74
Max Lift (Hembold): 1.10 lbf
CL and Cl
0.8
Theory1
0.6
0.4
0.2
0
-0.2
CL
-0.4
3D Lift Curve
CLmax Hembold
CLmax Estimate
-0.6
-5
1
2D Lift Curve
Cl
0
5
10
α (deg)
15
Anderson, J.D., Fundamentals of Aerodynamics, New York, 2001, pp 351-416
March 24, 2005
AAE 451 – Team 5
9
20
Aerodynamics - Drag

Parasite Drag Buildup
Component CDp
Wing:
0.017
Fuselage:
0.005
Horiz. Tail:
0.015
Vert. Tails:
0.004
Booms:
0.011
Wheels:
0.027
Struts:
0.0003
Misc:
0.004
CDp:
0.083
March 24, 2005
Total Drag:
CDp:
0.083
CDi:
0.029
CDtot:
0.112
Drag:
0.4473 lbf
CDp 
# comp
K i Qi C fi S weti
i 1
S ref

Sref = reference area [ft2]
Cf = skin friction coefficient
K = form factor
Q = interference factor
AAE 451 – Team 5
10
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°

2
L/D vs. α
15
10
8
10
L/D=4.7
6
L/D
5
4
20
0
-5
L/D
Loiter Requirement
L/D
-2
-10
-5
-4
-5
0
5
0
5
10
15
10
15
α (deg)
Raymer, D.P., Aircraft Design: A Conceptual Approach, Virginia, 1999, pp 27
March 24, 2005
AAE 451 – Team 5
11
Trim
20
20
Class 2 Tail Sizing (X-plot)
X-Plot for Horizontal Tail
1.5
x cg
xN
1.4
Location (normaclized about C
MAC
)
x acw
Desired SM
1.3
1.2
1.1
1
0.9
0.8
0
0.1
March 24, 2005
0.2
0.3
0.4
0.5
0.6
Tail Area [sq ft]
AAE 451 – Team 5
0.7
0.8
0.9
1
12
Trim Diagram
Trim Diagram for Cf /C = 0.5
0.05
0
e
-0.05
Cm
cg
-30
-10
-0.1
-0.15
-0.2
0
-0.25
0
0.2
March 24, 2005
6
3
0.4
0.6
CLtotal
0.8
AAE 451 – Team 5
0
12
9
1.2
1
10
30
13
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



March 24, 2005
AAE 451 – Team 5
14
Class 2 Vertical Tail Sizing (X-plot)
-3
14
x 10
Yawing Moment Coeff. Variation with Side Slip Angle vs. Vertical Tail Area
12
Cn vs. S v for our aircraft's dimensions
Desired Cn
10
8
C
n
6
4
2
0.001
|
0
|
|
-2
-4
0.218 ft2
|
|
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Sv [ft 2]
March 24, 2005
AAE 451 – Team 5
15
Feedback Controller
Pitch Rate Feedback to Elevator
Elevator Servo  1
Pitch Rate Gyro  1
March 24, 2005
AAE 451 – Team 5
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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
March 24, 2005
AAE 451 – Team 5
17
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
March 24, 2005
AAE 451 – Team 5
18
Propeller Plots – 6 inch prop
Loiter
Take-Off
Data for hypothetical propeller with tau= 0.66667
0.1
0
Thrust Coef, CT
0.2
CT*= 0.076352 for J*= 0.33566
0
0.05
0.1
0.15
0.2
0.25
0.3
Power Coef, CP
0.06
CP*= 0.042285 for J*= 0.33566
0.04
0.02
0
0
0.05
0.1
0.15
0.2
0.25
0.3
1
Eta*= 0.60609 for J*= 0.33566
0.5
0.1
0.05
CT*= 0.024906 for J*= 0.76
0.35
0
0
0.1
0
0.05
0.1
0.15
0.2
Advace ratio, J=V/(nD)
0.25
0.3
0.4
0.5
0.6
0.7
0.8
0.5
0.6
0.7
0.8
0.6
0.7
0.8
CP*= 0.022677 for J*= 0.76
0.02
0
0
0.1
0.2
0.3
0.4
1
Eta*= 0.83468 for J*= 0.76
0.5
X is the selected operating point
0.35
0
0
0.1
0.2
0.3
0.4
0.5
Advace ratio, J=V/(nD)
CT = 0.025
CP = 0.023
η = .83
CT = 0.076
CP = 0.042
η = .61
March 24, 2005
0.3
0.04
X is the selected operating point
0
0.2
0.06
0.35
Efficiency, eta
Efficiency, eta
Power Coef, CP
Thrust Coef, CT
Data for hypothetical propeller with tau= 0.66667
AAE 451 – Team 5
19
Motor Selection - Graupner Speed 400 6V
(Direct Drive) Characteristics
Engine Characteristics
Operating Conditions
March 24, 2005
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 RPM (Take Off)
14300 RPM
Input Voltage
8.34 Volts
Input Current
11.7 Amps
Output Power
0.078 hp
AAE 451 – Team 5
20
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.
March 24, 2005
AAE 451 – Team 5
21
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
•Parameters
•θ = 30°
•Material = Al
•Ngear = 3 (Gen. Av.)
Fl 3
S
sin 
3EI
Tail Gear (2)

18 gauge steel wire
 Prevent prop and tail strike

Gear deform instead of break
March 24, 2005
AAE 451 – Team 5
22
Structures - CG
Weight (lbf) Location (ft)
Motor
0.158
1.208
Speed Control
0.063
0.104
Batteries
0.188
0.083
Gear Struts
0.003
0.500
Wing
0.127
0.360
H-Tail
0.017
1.860
V-Tail
0.010
1.841
Booms
0.065
1.057
Wheels
0.025
0.334
Radio
0.040
0.104
Gyro
0.053
0.042
Wing Servos
0.040
0.279
H-Tail Servo
0.020
1.860
V-Tail Servo
0.020
1.841
Prop
0.060
1.214
Attachment mat.
0.006
CG
TOTAL
0.865
0.616
March 24, 2005
CG (ft)
CG (%)
xAC (ft)
xAC (%)
0.616
0.860
0.720
1.004
Static Margin (%)
0.145
AAE 451 – Team 5
23
Structures - Load Analysis

Structural loads from code – basic
equations used
 τ max
= 2.40 lbf/ft2
 Mroot = 0.26 ft-lbf
 σmax = 0.0048 lbf/ft2

Deflections
 δy
= 9.1e-11 ft
 δΦ = 1.1e-4 degrees
March 24, 2005
AAE 451 – Team 5
24
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.
March 24, 2005
AAE 451 – Team 5
25
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
March 24, 2005
AAE 451 – Team 5
26
Strength Testing
Failure at 26 lbf
March 24, 2005
AAE 451 – Team 5
27
Strength Testing
Pounds
Tip Deflection (ft)
0.88
0.0009
1.76
0.0076
2.65
0.0148
6.00
0.0228
12.00
0.0452
26.00
BROKEN
March 24, 2005
Failure due to buckling
AAE 451 – Team 5
28
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.

March 24, 2005
AAE 451 – Team 5
29
Manufacturing - Booms
Circular holes cut for boom insertion
 Foam is bonded inside and out to tube
 Boom pinned into place with wire

March 24, 2005
AAE 451 – Team 5
30
Overall Schedule

To be accomplished before 1st flight
Order parts – March 10
Build prototype wing – March 11
Test 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
March 24, 2005
AAE 451 – Team 5
31
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
March 24, 2005
AAE 451 – Team 5
32
Current Issues
Propeller air flow
 Engine heating
 Manufacturability

 Boom
attachments
 CG movement
March 24, 2005
AAE 451 – Team 5
33