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University of California, IrvineUCI Team Caddyshack
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The UCI AIAA student chapter participates in the annual AIAA Design
Build Fly (DBF) competition.
This competition gives the engineering students a chance to apply
classroom knowledge, gain hands on skills, and experience an
industry level project-development from conceptual design to
building and testing an optimized final product.
Over the past 6 years this project has grown substantially in size and
skill with the help of previous DBF students, currently working in the
aerospace industry, who meeting with the current team weekly.
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Introduction
Team Organization
2011 Competition
Conceptual Design
Preliminary Design
Detailed Design
Manufacturing
Testing
Expected Final Performance
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Project ManagerKamil Samaaan
Report
Lead: GiuseppeVenneri
Patrick Lavaveshkul
Semir Said
Westly Wu
Byron Frenkiel
CAD
Lead: PatrickLavaveshkul
Kerchia Chen
Sothea Sok
Angela Grayr
Erica Wang
Chief Engineer
Giuseppe Venneri
Aerodynamics
Lead: Curtis Beard
Rayomand Gundevia
Thuyhang Nguyen
Anthony Jordan
Max Daly
Propulsion
Lead: Kevin Anglim
Kasra Kakavand
Khizar Karwa
Alexander Mercado
Yi-lin Hsu
Structures
Lead: Hiro
Nakajima
Kurt Fortunato
Gagon Singh
Kevin Koesno
Michael Gamboa
Payload
Lead: Jacqueline
Thomas
Semir Said
Westly Wu
Stability andControl
Lead: David Martin
James Lewis
Giuseppe Venneri
Test FlightCoordinator
Alexander Mercado
Public Relations
Chen Weng
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Aerodynamics: Computes flight characteristics and necessary wing
dimensions.
Propulsion:Analyzes propulsion system to find best motor, propeller and
battery combination.
Structures: Optimizes load-bearing components and maintains a weights
build-up of the aircraft.
Payload:Designs and manufactures steel payload and restraints for the
payload and aircraft.
Stability & Control: Ensures aircraft meets S&C standards and works
closely with aerodynamics to predict flight performance.
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Competition consists of 3 missions:
Mission 1:Complete as many laps as possible in a 4-minutes. time
frame (M1 = Nlaps/Nmax)
Mission 2:3 laps with a steel bar payload.
(M2= 3x(Payload weight/Flight weight))
Mission 3:3 laps with
a team-selected
quantity of golf balls.
(M3 = 2x(Nballs/Nmax))
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Constraints for 2011:
Battery weight: lb
20 amp slow-blow fuse
Aircraft must fit in a commercially-available carry-on suitcase.
L + W + H = 45inches (no dimension can exceed 22 in.)
Suitcase must include entire flight system, including aircraft, battery and
all required parts and tools.
Golf balls are regulation sized and the steel bar payload dimensions are
constrained: 3 in. width x 4 in. length minimum.
Aircraft must be hand-launched.
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Sensitivity Analysis
Configuration Figures of Merit
Aircraft Configuration
Subsystems Selection
Motor Position
Landing Methods
Yaw Control
Wing Attachment Methods
Payload Configuration
Final Configuration
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The objective of this analysis is to identify the mission parameters
that have the largest impact on the score. A maximum of 64 golf balls and 9 laps were the benchmark values,
determined using the data from past DBF competitions.
Thrust and drag models were used in a simulation program to design
hundreds of planes and perform this analysis.
Mission 1 favors a small plane and
payload with a large propulsion
system.
Missions 2 and 3 favor a large
plane with a high wing loading.
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In order to select an aircraft configuration, a scoring system
based on figures of merit was produced. Each was weighted
based on results of the scoring analysis:
System weight (35%)
L/D (20%)
Cargo space (15%)
Maneuverability (10%)
Manufacturing (10%)
Hand launch (10%)
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Tractor- Lightweight, higher efficiency andless dangerous hand launch.
Pusher- greater lift due to lack of prop-
wash, limits the maximum amount of
sweep and a dangerous hand launch.
Double Tractor- Smaller propellers,
increased cargo space in center, less
dangerous hand launch, increased weight
and difficulty in locating the CG.
Push-Pull-Increased weight, limitsmaximum sweep and provides a more
dangerous hand launch.
FOMWeight
Single
Tractor
Single
Pusher
Double
Tractor
Push-Pull
System Weight 45 0 0 -1 -1
Drag 20 0 1 -1 0
Hand Launch 15 0 -2 1 -2
Stability 10 0 -1 0 -1
Cargo Space 10 0 1 2 -1
Total 100 0 -10 -30 -95
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Belly Landing-Low weight, low drag,
would be difficult to hand launch andvulnerable to fatigue.
Skid/ Handle-Improved hand launch,
increased structural support, potential
additional storage space and slight
increase in weight and drag.
Skid & Wire-Decreased stopping
distance, minor increase in weight and
increase in drag.
Tricycle-Reliable and high strength,
however significant increase in weight,
drag and difficulty of hand launch.
FOM Wt
Belly
Landing Handle/ Skid
Skid and
Piano wire Tricycle
System Weight 45 0 -1 -1 -2
Drag 20 0 0 -1 -2
Hand Launch 15 0 2 -1 -2
Stability 10 0 0 1 2
Cargo Space 10 0 2 0 0
Total 100 0 5 -70 -140
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Winglets-Reduced drag, lightweight and provides yaw stability.
Wingtip rudders- Increased pilot
control and increased weight.
Aft Vertical tail-Greater moment to
correct yaw and significant
increase in weight.
Split Flaps- Provides only a minor
increase in weight, complex and
difficult to implement correctly andcause and increase in drag.
FOMWeight Winglets
Wingtip
Rudders
Aft Vertical
Tail
Split
Flaps
System
Weight45 0 -1 -2 -1
Drag 25 0 0 -1 0
Hand Launch 15 0 0 -1 0
Stability 15 0 1 2 0
Total 100 0 -30 -100 -45
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Fully enclosed internal payload compartment-Less drag and a
lower weight. Requires a larger t/c airfoil or a larger aircraft.
Fuselage (BWB) style compartment-More efficient method of
cargo placement near the Center of Gravity, increased drag and
difficulty to manufacture.
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Design and Optimization Programs
Design Methodology
Mission Model
Aerodynamics
Airfoil Selection
Wing Sizing
Propulsion Sizing
Drag
Lift
Stability and Control
Mean Aerodynamic Chord
Winglets
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SolidWorks: used to model aircraft prototypes and to help determine
airfoil selection
XFOIL: Used to analyze possible airfoil choices for aerodynamiccharacteristics
Microsoft Excel: Used extensively for data analysis, storage andgraphing
AVL: Used for flight-dynamic analysis and to ensure overall stability
of the aircraft
MATLAB: Used to create an optimization program
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The mission profile was modeled using for loops and while loops in
MATLAB.
The aerodynamic and propulsion forces were computed for every loop-
iteration to determine the change in position and velocity of the aircraft
during that period of time.
The program assumed some initial conditions for takeoff such as handlaunch velocity and wind conditions.
The mission model program computes:
the energy used
the number of laps completed in 4 minutes
The maximum payload capacity a design could carry.
The total flight score is computed for several designs which resulted in
an optimized design.
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The majority of airfoils that were considered were the reflex type for our flying wing.
Studies were done using XFOIL and SolidWorks to determine which airfoil best suited
our needs.
Coefficient of moment vs. angle of attack NACA 4-digit symmetric series study
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Wing loading was optimized
based on the total flight score
using our mission profile MATLAB
program.
The figure to the right shows a
plot of the total drag as a function
of the aspect ratio for mission
three during takeoff.
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Battery Selection
Considered several different
battery types and the
capacity-to-weight ratios.
A mission profile was used to
determine an estimate of theamount of energy needed to
complete each of the
missions.Motor Selection
Based on the battery andthe current limitation of
20A, the maximum power
the battery could supply to
the motor is 300 W.
Propeller Selection
Pitch-High pitchperforms better at high
speeds while low pitch
performs better at low
speeds.
Diameter- Largerdiameter= more thrust
and more power
required from motor.
o Mission 1: High pitch
small diameter.
o Missions 2 & 3: Lower
pitch and larger
diameter.
Battery
Capacity mAh
Ah / oz
Redicom
500
1.56
Nimh
700 1.75
Elite 1500
1500 1.92Elite 1700
1700 1.7
Elite 2000
2000
1.72
Elite 2200
2200
1.44
Elite 3300
3300 1.71
Name Weight
oz
Kv
RP
M/V
Max
Current
Amp
Power
W
Resist
ance
Hacker
A30-14L
4.6
800
35
490
0.038
Hacker
A30-12L
4.6
100
0
32
400
0.041
Hacker
A30-10L
4.8
118
5
35
450
0.023
HackerA30-8XL
5.5
110
0
35
600
0.015
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The drag was computed using the equivalent flat plate area method.
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The wing was optimized
for the cruise of mission
two and three.
Washout helped focus
the peak of the CL
distribution.
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We calculated our MAC and
simulated our aircrafts geometry
through AVL
The figure to the right shows the
resulting pole-zero map of the
eigenvalues calculated by theprogram.
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WINGLETS
An eignemode analysis made in AVLshowed that the flying wing was susceptible
to low Dutch roll damping.
Dutch roll was clearly visible during test
flights, but Pilot still maintained good control.
Sized for Dutch roll damping above 0.02.
Optimized Winglet Dimensions
Height c/4: 9.5 in
Sweep: 37 degreesDistance behind LE: 6.0 in
Taper ratio: 0.7
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We modeled the wing sparas an I-beam.
Carbon strips were laid on
the top and bottom of the
wing with a 5/8 diameter
carbon rod running between
the strips to create our spar.
Testing later on showed that
the wing with two spars was
favored over the single spar.
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In an effort to reduce weight, the motor mount, landing skids and launch
handle were combined into one carbon fiber structure that was
integrated into the center wing section.
This design proved to be very efficient in cargo space utilization.
The forward end is used as an electronics compartment to house the
speed controller and the fuse.
The skid and handle section was designed as a channel that was sized to
fit the propulsion battery pack.
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Foam wings were
created and hollowed
out using wooden
templates and a hotwire
as investigated over
summer.
Wings were then coated
with fiber glass and a
strip of carbon fiber for
strength.
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Wingtip Testing
Propulsion Testing
Handle Design Tests
Flight Tests
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Wing tip testing was used to confirm and validate wing-sparcalculations and our hollow core foam design.
Testing was performed
by securing the tips
of a wing and loading
it mid-span until
failure occurred.
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Static thrust testing was conducted to measure the performance of various
propulsion systems.
Dynamic thrust testing was conducted using a load cell that was mounted to a
custom-designed sliding motor mount and was used to collect dynamic thrust
data during flight.
This data was used to accurately model the dynamic thrust in the mission profile
optimization program. Fuse and battery testing were also conducted in the lab to determine the limits
and range of operation.
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Different handle designs were
created and tested initially to
find which best suited the hand
launcher to give him control
and stability at take off.
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The following are a combination of both
prototypes, and were used to calibrate the
preliminary design.
Takeoff speed: 30 ft/s
Max wing loading: 28 oz
Locating CG for stable flight: 15% static
margin
Dutch roll damping: Controllable
Lap time: 37 s
Prototype I
Prototype II
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Prototype I
Provided insight into launch and landing techniques.
Provided data for the calibration of the wing loading.
Prototype II
Improved stability.
Increased payload space.
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The conditions surrounding the fuse inTucson are very different than those in Irvine.The fuse will blow at a lower current inTucson.
Flying later in the day helped with the abovehandicap, when it was cooler. In fact, heavyplanes like those from Israel and MIT skippedtheir noon rotation and waited till the lateafternoon to fly their airplanes (9 lbs!!).
Conduct propulsion tests and test flights withcompetition weather conditions in mind.