AAE 451 Aircraft Design
Project Presentation Boiler Xpress
December 5, 2000
Team Members
Oneeb Bhutta
Matthew Basiletti
Ryan Beech
Micheal Van Meter
Presentation Overview
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Design Mission
Concept Selection & Initial Sizing
Detailed Analysis:
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Aerodynamics
Structures
Propulsion
Stability, Dynamics, and Control
Conclusions
The Mission

Variable Stability Aircraft- Roll Axis


Flight Within Mollenkopf Athletic Ctr:


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1.2 lb payload
20 ft/s stall speed
12 minute Endurance/ electric power plant
Robust and Affordable
Transportable
Airframe cost < $200
Flight Mission
42’ Ceiling height
10 second “Straight Line”
35 ft Radius
120 ft. max T.O. roll
5.5 deg Climb Angle
Weighted Objectives Method
Score
% of
Total
Rank
30
10.0
7
Build within 3 weeks
10.0
9.16
4
Light weight
27.5
16.66
1
Turning radius
9.16
16.66
2
50
10
6
Transportability
16.66
4
9
Ease of analysis
50
7.5
8
Landing ability
16.66
2.66
10
Maintainability
30
10
5
Marketability
10
13.33
3
Objective
Endurance
Robustness
1
4
2
3
5
Constraint Diagram
Initial Sizing
Electric Models wing area vs weight
1800
wing area (sq.in.)
1600
1400
1200
1000
800
600
400
200
0
0
50
100
150
200
Weight (oz)
250
300
350
400
Geometry and Configuration
Boiler Xpress
11.1’
Wing:
•Sref = 13.5 sq.ft.
•Span = 11 ft.
•Aspect Ratio = 9
•Taper Ratio = 0.6 tip section
•Airfoil: S1220
Horizontal Stabilizer:
•Area = 1.83 sq ft.
•Span = 3.0 ft.
Vertical Stabilizer:
•Total Area: 1.15 sq.ft.
5.8’
Aerodynamic Design Issues
Lift
• Low Reynolds Number Regime
•
Slow Flight Requirements
Drag
• Power Requirements
•
Accurate Performance Predications
Stability and Control
• Trimmability
•
Roll Rate Derivatives
Low Reynolds Number Challenges
Separation Bubble-to be avoided!
•Laminar Flow -more Prone to Separation
•Airfoil Sections designed for Full-sized Aircraft
don’t work well for below Rn=800,000
•Our Aircraft Rn=100,000-250,000
Airfoil Selection
Wing:
Selig S1210
CLmax = 1.53
Incidence= 3 deg
Re = 150e3
0.06
0.05
flat plate for Low Re
Incidence = -5 deg
0.04
Cd
Tail sections:
FX63137
S1210
0.03
S1223
0.02
0.01
0
-0.2
0
0.2
0.4
0.6
0.8
1
Cl
1.2
1.4
1.6
1.8
2
2.2
Drag Prediction
Assume Parabolic Drag Polar
CD  CD0  KCL
1
K
Ae
e  0.75
2
Based on Empirical
Fit of Existing Aircraft
Parasite Drag
Drag Build-up Method of Raymer
C Do  
C f QFFS wet
S ref
(Ref. Raymer eq.12.27 & eq.12.30)

 Blasius’ Turbulent Flat Plate0.455
C f  1.2
2.58 
Adjusted for Assumed
log
10
(Re)


Surface Roughness
Drag Polar
Aircraft Drag Polar
0.16
CD
CDi
CDo
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
0.2
0.4
0.6
0.8
1
CL
1.2
1.4
1.6
1.8
Power Required
32
Predict:
• Battery energy for
cruise
28
Power Required [ft-lb/s]
• Power required for
cruise
30
26
24
22
20
18
16
15
20
25
30
Velocity [ft/s]
35
40
Aerodynamic Properties
Wetted area =
44.5 sq.ft.
Span Efficiency Factor = 0.75
CLa =
5.3 / rad
CL de =
0.4749 /rad
L/Dmax =
15.5
Vloiter =
24 ft/s
CLmax =
1.53
CLcruise =
1.05
Xcg =
0.10-0.38 (% MAC)
Static Margin = 0.12 at Xcg = 0.35
Stability Diagram
0.3
elev deflect=-8 deg
-4
0
4
8
0.2
Cmcg
0.1
elev deflect=-8 deg
-4
0
0
4
8
-0.1
-0.2
-0.3
-0.4
0
0.2
0.4
0.6
0.8
1
CL
1.2
1.4
1.6
1.8
Flow Simulation
Parasite Drag

CDo for Wing and Tail surfaces
t


4
FFW ing  1 0.6 c 100 t  1.34M 0.18
c 
x

c


 


For Fuselage, booms & pods
FFPOD
0.35
 1
f
 60
f 
FFFuselage  1  3  100 

f
400


(Ref. Raymer eq.12.31 & eq.12.33)
l
f 
d
Structures Outline
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Materials Employed for the structure
Mathematical Model
Bending Moment & Stresses; Wing Test
Equipment layout
Landing Gears & Landing Loads
Structural Materials
Balsa spars carry bending load
0.25 in x 0.25 in
T.E. Reinforcement
Styrene foam wing core
Materials Employed
Wing
Mathematical Model
Wing
Assumptions:
•Wing and Weight loading
•Method of Analysis (Theoretical Model)
•2.5g x 1.5
Horizontal Tail
Boom
P
Bending Moments
Max Moment = 41.71 lbf/ft
Stresses in Wing
 max
M max y

I
Sigmamax = 2003 psi
Sigmacritical = 1725 psi (Actual Test Result; Whiskey Tango Team, Spring
1999)
Reasons:
 Light Weight Structure
 Safety Factor (worst case scenario)
 Wing Test Results
P
1.5ft
Horizontal Tail & Boom
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Horizontal Tail:
Max Stress = 850psi
Spar Sizes = 1/8 in x 1/16in
Booms:
Max deflection = 0.24 in @ 2.5g’s x 1.5
Assuming Young Modulus (E) for a Carbon
Epoxy matrix.
Testing needed to verify result.
Material & Time Constraint
Equipment Layout & CG.
CG. = 30%~38% MAC
(Predicted)
CG. = 35% MAC (Actual)
Landing Gear
Rotation angle = 10 deg
Tip Back angle= 14 deg
Nose Gear: (3’’ from nose)
Main gears:
-6’’ from leading Edge
-Separation (1.5 ft)
From Raymer. Method of Sizing and
placement of Landing gears
Landing Loads
2
Ke  12 Wg Vvert
 7.6in  lb Vvert=2.2ft/s
d
Work   kSds  0.5k
0
Vland=1.3Vstall=25ft/s
For d = 1 in., k = 15.2 lb/in
For 1 inch strut travel, peak load = 15.2 lb
spar = 240 psi on landing
g = -5 deg
Propulsion Design Issues
Power
Special needs
Endurance
Propulsion system tests
Power
55
50
Power Required
Power Available
45
Power Required [ft-lb/s]
Power
required is
determined
by aircraft
Power
available
comes from
the motor
40
35
30
25
20
15
15
20
25
30
35
Velocity [ft/s]
40
45
50
Special Needs
Pusher configuration
Adjustable timing motor
Reversible motor
Propeller
High efficiency for endurance
Special propeller for electric flight
System Components
Propeller
Freudenthaler 16x15 and 14x8 folding
Gearbox
“MonsterBox” (6:1,7:1,9.6:1)
Motor
Turbo 10 GT (10 cells)
Speed Controller
MX-50
System Efficiencies
Propeller
60-65%
Gearbox
95%
Motor
90%
Speed Controller
95%
Total System Efficiency
50.7%
Propulsion Tests
Boiler Xpress Propulsion system Tests
1.8
1.6
1.4
1.2
Static
Thrust (lb)
1
Test1
Test2
0.8
Test3
Test4
0.6
Endurance
0.4
0.2
0
-0.2
0:00:00
0:02:53
0:05:46
0:08:38
Tim e (h:m m :ss)
0:11:31
0:14:24
0:17:17
Motor/Prop
Torque Sensor
Test Stand
Attached to
Wind Tunnel
Balance
To Batteries
Aircraft Analysis
Best Endurance Speed
Ve = 23.2 ft/s
Power Required at Best Endurance
Speed
Pr = 15.62 ft-lb/s
Flight Performance
Increased weight
17% increase
Increased cruise flight speed
22% increase
Lift coefficient
26% decrease
Endurance/Power
42% decrease in endurance
Flight Performance, Stability &
Control
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Sizing of horizontal and vertical tails
and control surfaces
Location of c.g. and aerodynamic center
Determination of static margin
Roll-axis block diagram
Transfer functions
Flight Performance Data
Horizontal and Vertical Tail
Initial Sizing
Sh 
Vh S ref c
xh
(8.3)
Sv 
Vv Sref b
(8.4)
xv
Vh - Horizontal tail volume coefficient = 0.50
Vv - Vertical tail volume coefficient = 0.044
Control Surface Sizing
Based on historical data from Roskam
Part II Tables 8.1 and 8.2.
Sa
S ref
Homebuilts
0.095
Single Engine
0.08
S a  1.35 ft 2
Sr
Sv
0.42
0.36
S r  0.80 ft 2
Se
Sh
0.44
0.42
S e  1.00 ft 2
Dihedral Angle
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

Paper by William McCombs suggests
0 – 2 degrees for RC aircraft with
ailerons.
Estimated by Raymer for a mid-wing
aircraft to be 2 – 4 degrees.
Our Aircraft- 2 degrees
X-plot Horizontal Tail
-Used to find elevator area
for desired Static Margin
0.8
SM  X ac  X cg
0.6
0.4
x/c
Xac = 0.46
Xcg = 0.35
SM = 11% MAC
cg location
neutral point
1
0.2
0
-0.2
-0.4
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
Horizontal tail area [sq ft]
2.8
X-plot Vertical Tail
0.6
Cnb = 0.11
CnBeta
Used to
determine
Weathercock
stability (yaw)
0.4
0.2
0
-0.2
-0.4
0.4
0.6
0.8
1
1.2
1.4
Vertical tail area [sq ft]
1.6
1.8
Flight Performance
Calculated Measured
Take-off Distance (ft)
56.7
70 (astroturf)
Turn Radius (ft)
50
< 40
Cruise Speed (ft/s)
24
28
Endurance (sec)
720
730
Block Diagram – Roll Axis
Tx
Servo
Rx
+
da
1
Aircraft
 /
Gyro
k
950
s  40s  950
2
62.31
s  76.85
P
Dynamic Modeling
Ld a 
Lp 
qSbCld
a
I xx
qSb 2Cl p
2 I xxU1
 rad 
 s 2 
 rad 
 s 
P( s)
62.31

d a ( s ) s  76.85
C ld a = 0.80
C l p = -0.15
Root Locus
De-stabilizing feedback
80
60
Imag Axis
40
20
0
-20
-40
-60
-80
-90
-80
-70
-60
-50
-40
-30
-20
Real Axis
-10
0
10
20
Nyquist Diagram
Nyquist Diagrams
From: U(1)
0.3
K = 0.3655
Gm=25.4284
0.1
To: Y(1)
Imaginary Axis
0.2
0
Pm=inf.
-0.1
-0.2
-0.3
-0.4
-1
-0.8
-0.6
-0.4
-0.2
Real Axis
0
0.2
0.4
Economics




Man-hours per week
Structural Cost Break-Up
Propulsion & Electronic Equipment Cost
Total Cost of the project
Man-Hours
BoilerXpress Man hours per Week
Total Team Hours
200
150
100
50
0
1
2
3
4
5
6
7
8
9
Number of Weeks
10
11
12
13
14
Structural Cost
Cost = $292.00
others
11%
Glue
23%
wires
9%
Balsa
7%
Carbon fiber
booms
22%
fiber glass
3%
foam
12%
Micafilm
13%
Structural Cost Break-Up
Structural Cost
Comp.
CST
CST
CST
Tower
Tower
Tower
Tower
Tower
Tower
Tower
Tower
Lowes
Cat. #
A105-A
A206-A
S-G01040-38
LXAS81
LXB243
LXB247
LXD867
LXD882
LXJC94
LXNK03
LXNK04
Description
105 resin
Slow Hardener (5:1)
Fiberglass 0.5 oz/sq-yd. (2 yards)
5510 Lite Ply 1/8"x6"x12" (6)
yellow Micafilm 65" (rolls)
yellow Micafilm 15' (rolls)
Dubro Threaded Rod 2-56x12" (6)
Dubro Nylon Kwik-Link Standard (2)
1/4"x3"x36" Balsa - 8pcs
Motor Wire (black)
Motor Wire (red)
Blue or Pink Foam (4'x8' sheets)
epoxy glue
Carbon fiber 1/2" x .032" x 60 " tubes for booms
screws and fasteners
Purdue University Stickers
spray paint
Qty.
1
2
1
1
1
1
1
3
1
2
2
2
1
2
1
2
1
Price/unit
$23.70
$11.40
$10.00
$12.59
$9.99
$26.99
$2.39
$0.70
$7.99
$6.49
$6.49
$17.00
$20.00
$32.75
$15.00
$4.99
$3.00
Total
subtotal
$23.70
$22.80
$10.00
$12.59
$9.99
$26.99
$2.39
$2.10
$7.99
$12.98
$12.98
$34.00
$20.00
$65.50
$15.00
$9.98
$3.00
$291.99
Motor & Electronic Equipment
Propulsion & Electronic Equipment Cost
Comp.
Hobby
Hobby
Hobby
Hobby
Hobby
MEC
Cat. #
HLAN241
HLAN3168
HLAN3186
HLAN4223
HLAN5145
Description
Qty.
1/4" Prop Shaft Adapter
14x8 Prop Blade
16x15 Prop Blade
47mm Middlepart Yoke
45mm Spinner
Motor Power Package
1
1
1
1
1
1
Price/unit subtotal
$1.00
$13.40
$15.30
$12.00
$5.00
$200.00
Propulsion
Tower
LXTX41
Radio Control System (transmitter, receiver etc.)
1
Battery packs
1
Battery charger
1
Hitec/RCD HS-55J Economy Sub Micro Servo Futaba2
Rate Gyroscope
1
$1.00
$13.40
$15.30
$12.00
$5.00
$200.00
$246.70
$250.00
$70.00
$100.00
$19.99
$109.00
Electrical Equipment
$250.00
$70.00
$100.00
$39.98
$109.00
$568.98
Total
$815.68
Total Cost
Build
55%
Preliminary
Design
41%
Man-Hour
Breakup
Rate = $75/hour
Testing
4%
Preliminary Design
Testing
Build
Test Material
Structural Cost
Prop and Elec Cost
hours
525
50
720
Total Cost
Cost
$39,375.00
$3,750.00
$54,000.00
$81.70
$291.99
$815.68
$98,314.37
Conclusions
Flight performance requirements met
Turn radius
Endurance
Take-off distance
Stabilizing feedback implemented
Future Work
Data logger installation
Implement destabilizing feedback
Refine propulsion analysis method (further testing)
Perfect construction method
Questions?