Project Presentation Boiler Xpress December 5, 2000
Team Members Oneeb Bhutta Matthew Basiletti Ryan Beech Micheal Van Meter
AAE 451 Aircraft Design
Presentation Overview Design Mission Concept Selection & Initial Sizing Detailed Analysis:
Aerodynamics Structures Propulsion Stability, Dynamics, and Control
Conclusions
The Mission
Variable Stability Aircraft- Roll Axis 1.2 lb payload
Flight Within Mollenkopf Athletic Ctr: 20 ft/s stall speed 12 minute Endurance/ electric power
plant Robust and Affordable Transportable Airframe cost < $200
Flight Mission
5.5 deg Climb Angle
35 ft Radius
120 ft. max T.O. roll
10 second “Straight Line”
42’ Ceiling height
1
2 3
4
5
ObjectiveScore % of
TotalRank
Endurance 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
Robustness 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
Weighted Objectives Method
Constraint Diagram
Initial Sizing Electric Models wing area vs weight
0
200
400
600
800
1000
1200
1400
1600
1800
0 50 100 150 200 250 300 350 400
Weight (oz)
win
g a
rea
(sq
.in
.)
Geometry and Configuration
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.
Boiler Xpress 11.1’
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
•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
Separation Bubble-to be avoided!
Airfoil Selection
Wing:Selig S1210
CLmax = 1.53 Incidence= 3 deg
Tail sections:flat plate for Low ReIncidence = -5 deg
Re = 150e3
0
0.01
0.02
0.03
0.04
0.05
0.06
-0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2
Cl
Cd
FX63-137
S1210
S1223
Drag Prediction Assume Parabolic Drag Polar
2
0 LDD KCCC
AeK
1
75.0e Based on Empirical Fit of Existing Aircraft
Parasite Drag
ref
wetfDo S
QFFSCC
(Ref. Raymer eq.12.27 & eq.12.30)
58.2(Re)10log
455.02.1fC
Drag Build-up Method of Raymer
Blasius’ Turbulent Flat Plate- Adjusted for Assumed Surface Roughness
Drag Polar
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.80
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
Aircraft Drag Polar
CL
CD CDiCDo
Power Required
15 20 25 30 35 4016
18
20
22
24
26
28
30
32
Velocity [ft/s]
Po
wer
Req
uir
ed [
ft-l
b/s
]
Predict:• Power required for cruise
• Battery energy for cruise
Aerodynamic Properties
Wetted area = 44.5 sq.ft.Span Efficiency Factor = 0.75CL=5.3 / rad
CL e = 0.4749 /radL/Dmax = 15.5Vloiter = 24 ft/sCLmax = 1.53CLcruise = 1.05Xcg = 0.10-0.38 (% MAC)Static Margin = 0.12 at Xcg = 0.35
Stability Diagram
elev deflect=-8 deg
-4
0
4
8
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
CL
Cm
cg
elev deflect=-8 deg
-4
0
4
8
Flow Simulation
Parasite Drag CDo for Wing and Tail surfaces
18.04
34.11006.01 Mct
cx
ct
FFWing
d
lf
400100
601
3
f
fFFFuselagef
FFPOD
35.01
(Ref. Raymer eq.12.31 & eq.12.33)
For Fuselage, booms & pods
Structures Outline
Materials Employed for the structure Mathematical Model Bending Moment & Stresses; Wing Test Equipment layout Landing Gears & Landing Loads
Structural Materials
Styrene foam wing core
Balsa spars carry bending load 0.25 in x 0.25 in
T.E. Reinforcement
Materials Employed
Wing
Mathematical Model
Wing
Assumptions:•Wing and Weight loading•Method of Analysis (Theoretical Model)•2.5g x 1.5 P
Boom
Horizontal Tail
Bending Moments
Max Moment = 41.71 lbf/ft
Stresses in Wing
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
I
yM maxmax
1.5ft
P
Horizontal Tail & Boom Horizontal Tail:
Max Stress = 850psiSpar 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
From Raymer. Method of Sizing and placement of Landing gears
Rotation angle = 10 deg
Tip Back angle= 14 deg
Nose Gear: (3’’ from nose)
Main gears:
-6’’ from leading Edge
-Separation (1.5 ft)
Vland=1.3Vstall=25ft/s
lbinVKe vertgW 6.72
21
kkSdsWorkd
5.00
For d = 1 in., k = 15.2 lb/in
= -5 degVvert=2.2ft/s
For 1 inch strut travel, peak load = 15.2 lb
spar = 240 psi on landing
Landing Loads
Propulsion Design Issues Power Special needs Endurance Propulsion system tests
Power
Power required is determined by aircraftPower available comes from the motor 15 20 25 30 35 40 45 50
15
20
25
30
35
40
45
50
55
Velocity [ft/s]
Pow
er R
equi
red
[ft-
lb/s
]
Power Required Power Available
Special Needs
Pusher configurationAdjustable timing motorReversible motor
PropellerHigh efficiency for enduranceSpecial propeller for electric flight
System Components
PropellerFreudenthaler 16x15 and 14x8 folding
Gearbox“MonsterBox” (6:1,7:1,9.6:1)
MotorTurbo 10 GT (10 cells)
Speed ControllerMX-50
System EfficienciesPropeller
60-65%
Gearbox95%
Motor90%
Speed Controller95%
Total System Efficiency
50.7%
Propulsion TestsBoiler Xpress Propulsion system Tests
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0:00:00 0:02:53 0:05:46 0:08:38 0:11:31 0:14:24 0:17:17
Time (h:mm:ss)
Th
rust
(lb
)
Static
Test1
Test2
Test3
Test4
Endurance
Torque Sensor
Motor/Prop
To Batteries
Test Stand Attached to Wind Tunnel Balance
Aircraft Analysis
Best Endurance SpeedVe = 23.2 ft/s
Power Required at Best Endurance SpeedPr = 15.62 ft-lb/s
Flight Performance
Increased weight17% increase
Increased cruise flight speed22% increase
Lift coefficient26% decrease
Endurance/Power42% decrease in endurance
Flight Performance, Stability & Control 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
v
refvv x
bSVS
h
refhh x
cSVS
Vh - Horizontal tail volume coefficient = 0.50Vv - Vertical tail volume coefficient = 0.044
(8.3) (8.4)
Control Surface Sizing
Based on historical data from Roskam Part II Tables 8.1 and 8.2.
ref
a
S
S
v
r
S
S
h
e
S
S
Homebuilts Single Engine
0.095 0.08
0.42 0.36
0.44 0.42
235.1 ftSa
280.0 ftSr
200.1 ftSe
Dihedral Angle 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
1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
Horizontal tail area [sq ft]
x/c
cg location neutral point
Xac = 0.46
Xcg = 0.35
SM = 11% MAC
cgac XXSM
-Used to find elevator area for desired Static Margin
X-plot Vertical Tail
0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
-0.4
-0.2
0
0.2
0.4
0.6
Vertical tail area [sq ft]
CnB
eta
Used to determine Weathercock stability (yaw)
Cn = 0.11
Flight Performance
Calculated MeasuredTake-off Distance (ft) 56.7 70 (astroturf)Turn Radius (ft) 50 < 40Cruise Speed (ft/s) 24 28Endurance (sec) 720 730
Tx
Rx 1
k
/
+ aP
Block Diagram – Roll Axis
85.76
31.62
s
95040
9502 ss
Servo Aircraf
t
Gyro
Dynamic Modeling
85.76
31.62
)(
)(
ss
sP
a
xx
l
I
qSbCL a
a
1
2
2 UI
CqSbL
xx
l
pp
p
a
l
l
C
C= 0.80
= -0.15
s
rad
2s
rad
Root Locus
-90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20-80
-60
-40
-20
0
20
40
60
80
Real Axis
Imag
Axi
s
De-stabilizing feedback
Nyquist Diagram
Real Axis
Imag
inar
y A
xis
Nyquist Diagrams
-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3From: U(1)
To
: Y(1
)
K = 0.3655
Gm=25.4284
Pm=inf.
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
0
50
100
150
200
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Number of Weeks
To
tal
Te
am
Ho
urs
Structural Cost
Glue23%
Balsa7%
Micafilm13%
foam12%
fiber glass3%
Carbon fiber booms22%
wires9%
others11%
Cost = $292.00
Structural Cost Break-UpStructural CostComp. Cat. # Description Qty. Price/unit subtotal
CST A105-A 105 resin 1 $23.70 $23.70CST A206-A Slow Hardener (5:1) 2 $11.40 $22.80CST S-G01040-38 Fiberglass 0.5 oz/sq-yd. (2 yards) 1 $10.00 $10.00
Tower LXAS81 5510 Lite Ply 1/8"x6"x12" (6) 1 $12.59 $12.59Tower LXB243 yellow Micafilm 65" (rolls) 1 $9.99 $9.99Tower LXB247 yellow Micafilm 15' (rolls) 1 $26.99 $26.99Tower LXD867 Dubro Threaded Rod 2-56x12" (6) 1 $2.39 $2.39Tower LXD882 Dubro Nylon Kwik-Link Standard (2) 3 $0.70 $2.10Tower LXJC94 1/4"x3"x36" Balsa - 8pcs 1 $7.99 $7.99Tower LXNK03 Motor Wire (black) 2 $6.49 $12.98Tower LXNK04 Motor Wire (red) 2 $6.49 $12.98Lowes Blue or Pink Foam (4'x8' sheets) 2 $17.00 $34.00
epoxy glue 1 $20.00 $20.00Carbon fiber 1/2" x .032" x 60 " tubes for booms 2 $32.75 $65.50screws and fasteners 1 $15.00 $15.00Purdue University Stickers 2 $4.99 $9.98spray paint 1 $3.00 $3.00
Total $291.99
Motor & Electronic Equipment
Propulsion & Electronic Equipment Cost
Comp. Cat. # Description Qty. Price/unit subtotalHobby HLAN241 1/4" Prop Shaft Adapter 1 $1.00 $1.00Hobby HLAN3168 14x8 Prop Blade 1 $13.40 $13.40Hobby HLAN3186 16x15 Prop Blade 1 $15.30 $15.30Hobby HLAN4223 47mm Middlepart Yoke 1 $12.00 $12.00Hobby HLAN5145 45mm Spinner 1 $5.00 $5.00MEC Motor Power Package 1 $200.00 $200.00
$246.70Radio Control System (transmitter, receiver etc.) 1 $250.00 $250.00Battery packs 1 $70.00 $70.00Battery charger 1 $100.00 $100.00
Tower LXTX41 Hitec/RCD HS-55J Economy Sub Micro Servo Futaba2 $19.99 $39.98Rate Gyroscope 1 $109.00 $109.00
$568.98
Total $815.68
Propulsion
Electrical Equipment
Total CostMan-Hour Breakup
Rate = $75/hour
hours CostPreliminary Design 525 $39,375.00
Testing 50 $3,750.00Build 720 $54,000.00
Test Material $81.70Structural Cost $291.99
Prop and Elec Cost $815.68Total Cost $98,314.37
ConclusionsFlight performance requirements met
Turn radiusEnduranceTake-off distance
Stabilizing feedback implementedFuture Work
Data logger installationImplement destabilizing feedbackRefine propulsion analysis method (further testing)Perfect construction method
Questions?
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