solar splash 2014 technical...
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The College of New Jersey
Solar Splash 2014 Technical Report
May 5th, 2014
Boat # 6
Team Members
Jeffrey Holman (M.E.)
Jason Pfund (M.E.)
Robert Ruff (M.E.)
Michael Schuhlein (M.E.)
Joseph Maco (Comp. E. )
Faculty Advisors
Dr. Karen Yan (Primary Advisor)
Dr. Seung-yun Kim (Electrical Advisor)
Dr. Norm Asper (Mechanical Advisor)
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EXECUTIVE SUMMARY
The IEEE Solar Splash competition is an annual intercollegiate international solar/electric boat
regatta. Each entry boat powered though direct and stored solar energy will compete in a sprint,
endurance and slalom race. The sprint competition demonstrates the boat’s ability to traverse at
high speeds while still having efficient use of the electrical power. The endurance competition
tests the boat’s ability to travel long distances using battery and solar power, thus demonstrating
the efficiency of the boat’s electrical system. During the slalom race the boat needs to show great
maneuverability. To address these design challenges, this year’s team identified four key areas
for improvement, and the design objectives are reducing overall weight of the boat, increasing
efficiency of the sprint propeller, a module design of drivetrain, and responsive steering.
The team designed a new hull that takes its inspiration from a surfboard shape, in an effort to
break away from the standard compromised monohull and gain an advantage in the competition.
This surfboard shape design has features that enable great performance in both the sprint and
endurance events. The design has a flat shaped hull in the back for greater planing abilities as
well as a smooth bow stem in the front for wave shedding at low speeds. The design speed has
been set for both the sprint and endurance races at 40 mph and 12 mph, respectively. These
speeds were chosen based on winning times from previous year’s competitions.
Propeller design is another aspect that was focused on for this year’s team, as the propeller is a
key contributing factor to the overall performance and efficiency of the boat’s drivetrain. The
2012 TCNJ team explored in-house propeller design and fabrication, an endurance propeller was
designed that achieves ample efficiency and performance. Built upon previous success, a sprint
propeller was designed and will be implemented for the competition this year. Software
OpenProp version 3.3.3. was used for the design and optimization of the propeller. By providing
the input parameters such as thrust, number of blades, and RPM range the program would
provide a propeller geometry that could then be used to generate a solid model for manufacturing
in a 5-axis CNC.
To keep the overall weight of the boat minimal while also accounting for the center of flotation
shift to change the boat position in the water, a modular drivetrain was designed in which a
separate set of motors and gearbox was designed for both sprint and endurance competitions,
with the unused configuration to be used as ballast. This design was chosen after determining
that the single motor used last year could not effectively provide the necessary performance in
the sprint competition with the current electrical system. The new design added simplicity to the
boat configurations by allowing for ballast to be used to optimize center of flotation positions. In
addition, it kept the overall weight of the boat minimal by making use of the same powerhouse,
transom, pintle, driveshaft, and lower unit.
The comfort and maneuverability of the skipper needed to be addressed so a push/pull cable
steering system was used, with the helm reused from 2013’s team, as it provided controls that
offered familiarity to that of an automobile and would allow the driver to operate the vehicle
with little to no learning curve.
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This year’s team is reusing previous year’s electrical systems and reconfiguring it to meet the
team’s specifications. New batteries were selected to meet the new weight allowance for the
endurance batteries (now 100 pounds). In addition the team will be adding a second motor
controller to the electrical system to handle the dual motors in the sprint configuration. The
telemetry system for this year’s design includes sensors to monitor voltage, current, rpm and
speed of the boat. The telemetry allows the on shore team to analyze data from the boat and
make decisions for the driver to maximize performance during the competition.
Currently the boat has been entirely designed and constructed. Design iterations were also
carried out to address issues identified during the fabrication process. Static testing has been
performed to determine weight management characteristics. The remaining tests for the boat are
dynamic testing. Both the sprint and endurance configurations will be tested in a lake to ensure
all sub systems are functioning properly and to determine optimal operating conditions.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY ................................................................................................................... ii
List of Figures ........................................................................................................................................ vi
List of Tables .......................................................................................................................................... vi
I. CURRENT DESIGN AND PROBLEM STATEMENT ............................................................ 1
II. DESIGN PROCESS SUMMARY......................................................................................................... 2
III. DESIGN CONCEPTS .......................................................................................................................... 2
A. Hull .................................................................................................................................................................... 2
1) Hull Design .................................................................................................................................................................. 2
2) Hull Materials ............................................................................................................................................................. 3
B. Steering ............................................................................................................................................................ 4
C. Drivetrain ........................................................................................................................................................ 4
D. Propeller ......................................................................................................................................................... 4
E. Electrical .......................................................................................................................................................... 5
F. Telemetry ........................................................................................................................................................ 5
IV. DESIGN DESCRIPTION.................................................................................................................... 6
A. Hull .................................................................................................................................................................... 6
1) Hull Design .................................................................................................................................................................. 6
2) Hull Materials ............................................................................................................................................................. 6
3) Hull Construction ..................................................................................................................................................... 7
B. Steering ............................................................................................................................................................ 9
C. Drivetrain ........................................................................................................................................................ 9
D. Propeller ......................................................................................................................................................... 9
E. Electrical ....................................................................................................................................................... 11
F. Telemetry ..................................................................................................................................................... 12
V. DESIGN EVALUATION .................................................................................................................... 12
A. Hull ................................................................................................................................................................. 12
1) Hull Design ................................................................................................................................................................ 12
2) Hull Materials ........................................................................................................................................................... 14
B. Steering ......................................................................................................................................................... 14
C. Drivetrain ..................................................................................................................................................... 15
D. Propeller ...................................................................................................................................................... 15
E. Telemetry ..................................................................................................................................................... 16
VI. PROJECT MANAGEMENT ............................................................................................................. 16
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A. Team Organization and Responsibility ............................................................................................. 16
B. Project Planning and Schedule ............................................................................................................. 17
C. Financial and fund-raising ..................................................................................................................... 17
D. Strategy for Team Continuity and Sustainability .......................................................................... 18
VII. CONCLUSIONS AND RECOMMENDATIONS........................................................................... 18
A. Strengths ...................................................................................................................................................... 18
B. Weaknesses ................................................................................................................................................. 18
C. Future Development ................................................................................................................................. 18
D. Goals Summary .......................................................................................................................................... 18
E. Recommendations ..................................................................................................................................... 18
REFERENCES .......................................................................................................................................... 19
Appendix A: Batteries ........................................................................................................................ 20
Appendix B: Flotation Calculations ............................................................................................... 22
Appendix C: Proof of Insurance ...................................................................................................... 23
Appendix D: Team Roster................................................................................................................. 24
APPENDIX E: HULL ANALYSIS ......................................................................................................... 25
Appendix E.1 .................................................................................................................................................... 25
Appendix F: Drivetrain ...................................................................................................................... 27
F.1 Timing Belt/Pulley Specifications ..................................................................................................... 27
F.2 LEM-200 D126 Specifications ............................................................................................................. 31
............................................................................................................................................................................... 32
F.3 Perm PMG-132 Specification............................................................................................................... 33
F.4 Bearing Data.............................................................................................................................................. 34
F.5 ANSI Key Standards ................................................................................................................................ 35
Appendix G: Propeller ....................................................................................................................... 36
Appendix G.1: Stress Analysis .................................................................................................................... 36
Appendix G.2: Cavitation Analysis ........................................................................................................... 39
Appendix G.3: Manufacturing .................................................................................................................... 40
Appendix H: Eletrical Systems ........................................................................................................ 43
Appendix H.1: SCHOTT 240 W Solar Panel Data Sheet ...................................................................... 43
Appendix I: Telemetry ...................................................................................................................... 47
Appendix I.1: XStream-PKG-R RF Module ............................................................................................. 47
Appendix I.2: L01Z600S05 600A Hall Effect Current Sensor.......................................................... 53
Appendix I.3: CSLA2CD 72A Hall Effect Sensor Data Sheet ............................................................. 55
Appendix I.4: OPB715Z Optical Sensor ................................................................................................... 57
Appendix I.5: EM-406A GPS Module ........................................................................................................ 58
Appendix I.6: Arduino Mega Datasheet ................................................................................................. 62
Appendix I.7: Matrix Orbital LK204-25-WB Data Sheet .................................................................. 66
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Appendix J: Project Management .................................................................................................. 68
Appendix J.1: Team Gantt Chart ............................................................................................................... 68
Appendix J.2: Sponsorship Brochure ..................................................................................................... 69
Appendix J.3: Materials and Travel Budget.......................................................................................... 70
List of Figures Figure 1 - 80/20 Aluminum Rails ................................................................................................................. 3
Figure 2 – Bracket designed to attach a pulley to the bottom of the helm .................................................. 3
Figure 3 - Endurance Power head (Left) Sprint Power head (Right) ............................................................ 4
Figure 4 – Proposed 2014 Hull Design for TCNJ (Solid Model in SolidWorks with Dimensions) ............. 6
Figure 5 - Foam & Wood laid out before construction ................................................................................. 7
Figure 6 - Rough bow stem shaping (left) versus finished bow stem (right) ................................................ 8
Figure 7 - Final sprint propeller design modeled in SolidWorks from Table 1 parameters........................ 10
Figure 8 - Endurance Electrical Configuration (Left) and Sprint Electrical Configuration (Right) ........... 11
Figure 9- Testing the Endurance Configuration to Try and Achieve Lifting the Transom Out of the Water
.................................................................................................................................................................... 13
Figure 10- Testing the Sprint Configuration to Achieve Neutral Trim Angle for Planing Capabilities ..... 14
Figure 11 - Drivetrain assembly.................................................................................................................. 15
Figure 12 – Prototype g-code tested using Butterboard (left) and aluminum propeller after machining
(right). ......................................................................................................................................................... 16
Figure 13 - Comparison of the Full Hull versus Submerged Portion of Hull in the Water ........................ 25
Figure 14 - Comparison Demonstrating the Reduced Drag Force and Vortex Shedding Between Transom
In (Left) and Transom Out (Right) ............................................................................................................. 25
Figure 15 - Proposed Weight Management Configuration (Endurance Event) .......................................... 26
Figure 16 - Surface finish of the roughing pass by the CNC mill. A 1/2" end mill was used to quickly
remove large amounts of material. .............................................................................................................. 40
Figure 17 - FInishing pass by the CNC mill. Foam plugs were used to dampen blade vibrations caused by
the mill. A water-soluble oil coolant was used. .......................................................................................... 40
Figure 18 - Machined surface finish resulted in small lateral ridges. ......................................................... 41
Figure 19 - Fine sand paper was used to smooth out the ridges to improve fluid flow characteristics. ..... 41
Figure 20 – Aft view of the final machined sprint propeller. ...................................................................... 42
Figure 21 - View of the sprint propeller mounted on the lower unit. This will attach to the drive shaft of
the drivetrain. .............................................................................................................................................. 42
List of Tables Table 1 - Hullform Comparison Chart [1] ...................................................................................................... 2
Table 2 - Decision Matrix for Propeller Designs .......................................................................................... 5
Table 3 - Specific Weight of Used TCNJ Core Hull Materials .................................................................... 7
Table 4 - Sprint Propeller input and output parameters for final propeller design ..................................... 10
Table 5 - Results of Stress Analysis for Sprint Propeller ............................................................................ 11
Table 6 - Summary of the Flotation Requirement Calculations.................................................................. 22
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Table 7 - Data Analysis for the Waterline Properties of the Hull ............................................................... 25
Table 8 - Comparison of Drag Forces Between the Proposed Design and Past Years at TCNJ ................. 26
Table 9- Sprint Propeller Input Parameters for Cantilever Beam Stress Analysis ...................................... 36
Table 10 - Calculations for Cantilever Beam Stress Analysis .................................................................... 37
Table 11 - Output of Cantilever Beam Stress Analysis .............................................................................. 39
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I. CURRENT DESIGN AND PROBLEM STATEMENT
The Solar Splash competition is a five-day event in Dayton, Ohio, in which college teams from
different parts of the world come together to compete with their solar/electric watercraft.
Previous years’ designs were reviewed to make improvements and design changes where
necessary. In the past, teams have been less effective in the sprint competition. This was due to
the added weight of a catamaran design which prevents effective planing capabilities of the boat.
In addition, past teams have experienced cavitation problems with the propeller. This caused a
large loss of efficiency and prevented the boat from achieving its maximum theoretical speed.
The steering system in the past used a sprocket that resulted in decoupling of the system during
configuration changes. A great design in past years’ teams was the inclusion of 80/20 aluminum
rails that allowed for the quick and easy weight configuration changes in between competitions.
The 2014 team designed and manufactured a new, competitive boat to meet the following
objectives:
Hull Design
o Design hull to be efficient in sprint and endurance competitions
o Design for lightweight hull
o Ensure easy configuration changes between events
o Implement 80/20 rail system for weight changes
Steering
o Achieve 60° of rotation while avoiding derailment or locking points
o Must be stable for the sprint race to ensure the safety of the driver
o System must be able to accommodate any changes to the boat while configuring
to different races
Drivetrains
o Design a modular drivetrain setup to maximize performance across all
competitions
o The endurance system must deliver a speed of 550 RPM at the propeller
o The sprint system must deliver a propeller speed of 3400 RPM
Propeller
o Utilize available software to develop an optimized blade for the sprint race
o Design to minimize the effects of cavitation
o Design for manufacturability
Electrical System
o Design a motor controller system to maximize the efficiency in endurance race
o Integrate the donated solar panels into the system to power the boat
Telemetry
o Provide real time data for the following
Solar array voltage
Battery voltage
Battery current
Solar array current
Propeller RPM
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II. DESIGN PROCESS SUMMARY
The 2014 Solar Splash team divided up the design of a new solar boat amongst five
interdisciplinary members. A variety of design options were considered and a variety of analyses
were conducted to ensure the most optimal design was chosen. Each design was then compared
to the team goals and objectives. During construction several design issues were encountered and
solutions had to be found for each one. Overall, the boat was designed around a surfboard-style
hull in an effort to produce a groundbreaking design. Drag was calculated on the hull, from
which an appropriate propeller thrust was determined. The speed at which the propeller needed
to rotate was then given to the drivetrain engineer, who created two power heads specialized for
the endurance and sprint competitions, and provided the necessary RPMs through gear reduction.
A push/pull steering system was then designed to provide the boat with the maneuverability
required to compete across all events. Selection of batteries was then made, and motor
controllers were selected to optimize drivetrain efficiency and performance. Telemetry was
designed to record important parameters from the boat, including amp draw, battery life, and
RPM of the propeller. These parameters could then be transmitted to an on-shore laptop to
actively monitor the boat’s performance.
III. DESIGN CONCEPTS
A. Hull
1) Hull Design
Based on the competition events, each boat must be capable of performing at high and low
speeds (in the sprint and endurance competition). This essentially goes against typical hull design
techniques, in that hulls are typically designed for either high or low speed to maintain efficiency
for the intended use. Table 1 shows some fundamental hull design characteristics.
Table 1 - Hullform Comparison Chart [1]
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Previous TCNJ hull designs include semi-displacement monohulls (hybrid monohull) and both
displacement monohull & planing monohulls in the form of a catamaran. The hybrid monohull
has competed well in the past because of the unique design, featuring a flat planing hull aft and a
canoe shaped displacement hull towards the bow. The catamaran design of the 2013 team placed
well in the endurance competition however lacked the necessary planing performance for the
sprint event. . Taking a second look at the chart, the next design choice to push the envelope for
competition performance would be a hydrofoil design because of its superior performance across
the board. However, due to the limited resources of TCNJ teams, hydrofoil designs were ruled
out.
To be more competitive a complete redesign of the hull was determined to be necessary. The
design goals included reducing the overall weight of the hull, while maintaining both
displacement and planing hull characteristics and designing for ease of construction to minimize
construction hours while maximizing testing time. The team came up with a new surfboard
inspired hull design concept. The team decided to not reuse the hybrid monohull to explore
lightweight materials and to reduce the overall weight of the hull. The hull was designed to have
a flat planing section in the back for low drag at high speeds
and gradual bow stem towards the front to induce wave
shedding and to reduce drag at lower speeds. The hull also
builds off the catamaran design in the form of the modular
weight management system utilizing 80/20 aluminum rails,
shown in Fig. 1, as attachment points for sub systems. This
would allow the team to make major or minor weight
management adjustments during static testing to achieve the
proper center of flotation for each specialized event (bow heavy
for endurance to lift the transom out of the water and neutral-
stern heavy in the sprint configuration to achieve planing
quickly). Although a major portion of the hull is a flat planing
hull, the team predicts with proper weight management this flat
shape will be competitive in the endurance competition as well.
2) Hull Materials:
To follow through with the team’s goal of reducing the overall weight of the hull, material
selection was taken into careful consideration. The 2009 TCNJ hull was built from a fiberglass
epoxy sandwich with ¼” balsa wood core. This hull was relatively light, however, the nature of
the balsa wood fabrication techniques meant another all wood hull would greatly increase the
construction time, thus going against one of the team’s set forth goals. Therefore, extruded
polystyrene foam was chosen as the core material of the hull. In addition, white cedar stringer
inserts would be provided as a source of rigidity for the hull as well as serving as the locations of
mounting the 80/20 aluminum rails and keels. These lightweight materials are the core of the hull
and wrapped in an epoxy resin fiberglass outer shell to further increase the rigidity and
uniformity of the hull design.
Figure 1 - 80/20 Aluminum Rails
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B. Steering
One of this year’s team goals was to reduce the overall weight of
the boat. The steering system was designed using a push-pull
cable system. To use this design, a few modifications had to be
made to the lower unit and last year’s helm. A bracket was
designed to allow a cable to attach to the steering column’s
sprocket and then extend out of both sides of the helm using a
doublewide pulley; essentially running the cable down both sides
of the boat. This bracket can be seen in Fig. 2, which will mount
to the bottom of the helm and have a pulley attached to it. Also another bracket was designed to
attach to the power head couple, allowing the cable to properly turn the boat. This design would
also allow for any minor height adjustments when transitioning between events. Both of these
modifications were designed to allow the skipper 60 degrees of steering and ease of transitioning
configurations between events.
C. Drivetrain
For this year’s competition, the team immediately considered continuing the compound
drivetrain design of the 2013 TCNJ Solar Splash team. It was the goal of the team to design and
manufacture a drivetrain that minimized weight, and facilitated configuration changes between
each competition. The first design iteration made use of three motors attached to one gearbox,
with a single belt used to change between configurations. Though an elegant design, it was found
that three motors mounted to the gearbox rendered the center of flotation too far aft. To address
this, the final design was to create two gearboxes, and to interchange them between
competitions.
Figure 3 - Endurance Power head (Left) Sprint Power head (Right)
The endurance and sprint power heads can be seen in Fig. 3. The powerhouse, driveshaft, and
lower unit would be shared in both configurations to reduce weight by not needing duplicates of
these items.
D. Propeller
TCNJ teams have previously explored custom propeller designs for both the sprint and
endurance events. The endurance propeller that has been designed and fabricated has performed
well in previous years. This year’s team is focusing on a propeller design for the sprint
Figure 2 – Bracket designed to attach a pulley to the bottom of the helm
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competition. Three different propeller types were considered – the advantages and disadvantages
are shown in Table 2. Surface piercing propellers have been widely used by professional
motorboat racing teams due to their extremely high efficiency. In its operation, the propeller is
only partially submerged with the waterline slightly below the hub. The result of this is two-fold
- there is a reduction of appendage drag and an elimination of cavitation, a phenomenon that
causes a loss of efficiency and damage to the propeller. Contra-rotating propellers operate fully
submerged with two coaxial propellers rotating in opposite directions. This configuration results
in moderate gains in efficiency by recovering the induced rotational energy that would be lost
from a single propeller. Conventional submerged propellers are used for a wide range of
applications due to the lower complexity of design and operation. The conventional propeller
was selected for this year due to the availability of software and empirical methods for the design
of the blade geometry.
Table 2 - Decision Matrix for Propeller Designs
Propeller Type Advantages Disadvantages
Surface Piercing High relative efficiency, no
cavitation
Complex design & analysis
Contra Rotating Moderate relative efficiency Complex gearbox
Conventional Submerged Simpler relative design &
analysis
Lower relative efficiency
E. Electrical
This year’s electrical system is designed and reused after the previous year’s electrical systems.
Notable design changes for this year include battery selection and motor controller addition. The
Solar Splash competition set new rules that allowed teams to have 100 pounds of batteries for the
endurance competition. In addition, for the sprint completion this year’s team intends to use two
motors, thus a second motor controller will need to be worked into the existing system.
F. Telemetry
For the telemetry design, each data acquisition module was carefully selected. It is mandatory
that data measurements have minimal impact on the electrical systems of the boat. Hall Effect
sensors where chosen to measure battery and solar array current as they the magnetic field
created by current flow minimizing the power draw on the electrical systems. Rail-to-rail
operational amplifies were selected for voltage measurements to minimize current draw on the
circuit.
The speed of the boat is measured through the use of a global positioning system (GPS) receiver.
The GPS module is able to provide accurate data for all conditions that the boat will experience.
The rotations per minute (RPM) of the motor is measured using an optical sensor. All of this data
is collected by a microcontroller unit (MCU). An embedded system was chosen due to their
efficiency and size advantages. The MCU is programmed in the C programming language. Radio
frequency (RF) modules were selected to transmit the collected to the on-shore subsystem. RF
was chosen for its stability and cost effectiveness. The data on-shore is viewed using a laptop.
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IV. DESIGN DESCRIPTION
A. Hull
1) Hull Design
Previous TCNJ hull designs have been designed and analyzed in a variety of commercially
available software. The 2009 monohull was designed in SolidWorks using MaxSurf to analyze
the hydrostatic and hydrodynamic characteristic of the hull. The 2013 team utilized the Orca 3D
plug-in for Rhinoceros 4.0. The Orca 3D software worked well for the 2013 because their
catamaran design consisted of true displacement and true planing hulls. Since the hull choice for
this year was an uncommon hull shape, SolidWorks modeling was used instead. In addition, the
hull was analyzed for hydrostatic and hydrodynamic performance within SolidWorks using mass
property evaluation features and SolidWorks flow analysis. Design parameters were varied
during the optimization process of the hull shape, including the overall hull length, hull width,
hull thickness and bow stem transition placement. To make the process as efficient as possible,
cross sections spaced one foot apart were utilized in the solid modeling program. This allowed
the designer to sketch cross sections of the hull and change parameter dimensions more quickly.
Each cross section was sketched as a half and then a loft function was used to generate a solid
shape, which was then mirrored about the center to create the full hull. The final hull shape can
be seen below in Fig. 4.
Figure 4 – Proposed 2014 Hull Design for TCNJ (Solid Model in SolidWorks with Dimensions)
To analyze the new hull design hydrodynamic simulation was carried out using SolidWorks fluid
flow software. Values of the previous year’s hull were obtained and then an analysis was run for
the proposed design. At our target speed of 12 mph in the endurance race (simulating the
transom out of the water) it was found that the proposed design experienced 30.35 lbs of drag, a
reduction of 37% compared to the catamaran. The team felt this decrease in drag force deemed
the new design a feasible design choice for this year’s competition.
2) Hull Materials
The choice of hull materials was based on the values of specific weights shown in Table 3. These
materials were extensively tested for material properties during the 2009 year and each would be
a valid design choice. The extruded polystyrene foam allowed the team to reduce weight while
still maintaining high flotation characteristics. The white cedar stringers were chosen because of
their relatively lightweight compared to okume plywood and it is relatively harder than balsa
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wood providing both rigidity and serving as an anchor location for screws and bolts to hold on
the subsystems.
Table 3 - Specific Weight of Used TCNJ Core Hull Materials
3) Hull Construction:
To construct the hull, female cross section plugs were made out of a hard cardboard material.
This would allow the team to shave away at a foam and wood blank plug to meet the desired
shape. Owen’s Corning generously donated all the extruded polystyrene foam for this year’s boat
again in 4’ x 8’ x 2” sheets. These sheets were cut down to size, in halves, thirds and two thirds
and glued together with epoxy and resin. The raw materials can be seen laid out in Fig. 5. The
foam pieces were layered in such a way that no butt joints were directly above or below each
other to make a more structurally sound hull. Once the foam pieces were all glued together the
next step was to attach the foam pieces to the wooden inserts. This was done by laying down a
sheet of fiberglass between the wood and foam and then using straps to ensure a uniform finish.
Next full scale drawings (top view and side view) of the bow stem shape were printed and taped
to the foam plug. Extensive bow stem shaping was conducted using saws, orbital sanders and
hand held rasps. An example of the rough bow stem and fiber glassed bow stem with body filler
can be seen in Fig. 6 below. A female plug was used to shape the sides to a nice rounded chine
along the entire length. Before fiber glassing the hull, any high or low spots were taken care of
by sanding and using lightweight automobile body filler. The keels were then attached to their
desired positions. Then once the final desired shape was obtained the top was glassed using an 8
ounce grade fiberglass whereas the bottom was glassed using a 6 ounce sheet. This was done to
reduce weight on the bottom where it was less likely for the hull to be stepped on and have
components moved around. The last step was a final sanding ending with a primer coat and final
coat of paint.
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Figure 6 - Rough bow stem shaping (left) versus finished bow stem (right)
Figure 5 - Foam & Wood laid out before construction
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B. Steering
To create an efficient and also ergonomic design, the bracket was fitted to the bottom of the helm
allowing the pulley to guide the cable underneath the helm. The double pulley attached
underneath the helm has the cable crossed so that the proper turn of the steering wheel
corresponds to the proper turn direction of the boat.
The cable runs down both sides of the boat along the 80/20 rails, keeping it protected and out of
the skipper’s way. The bracket attached to the power head couple was created using a shaft
collar to allow for minor height adjustments with the outboard motor. This design, paired with
the sprocket attached to the steering column, will allow the skipper to properly turn the boat a
total of 60 degrees. Also, this overall design allows the skipper to only have to turn the steering
wheel a minimal amount to turn.
C. Drivetrain
The 2014 team drivetrain makes use of two separate power heads dedicated for the sprint and
endurance events, respectively. Through coordination with the propeller designer, an operating
speed of 500RPM was decided for the endurance competition and a speed of 3400RPM was
decided for the sprint configuration, to optimize the performance of the propeller.
The endurance power head made use of a PMG132 motor, which applies a speed of 1080 RPM
when run at 24V. The motor shaft has a 20 tooth pulley mounted, and this pulley drives a 40
tooth pulley on the driveshaft, producing a 1:2 ratio and stepping the RPM down to 540; through
the 14:15 Konny Racing lower unit, the RPM is stepped down to a final speed of 504.[2]
The sprint power head makes use of dual Lynch LEM200 D126 motors to run a single
driveshaft. The motors run at a rated 3600RPM at the 36V power supply. The motors each have
a 20-tooth pulley, which drives another 20-tooth pulley on the driveshaft to provide a 1:1 ratio.
When combined with the lower unit, the final speed attained is 3360 RPM, which closely models
the design RPM.
Both power heads make use of a square couple. This square couple will allow for facilitated
configuration changes. The Solar Splash rules specify that all components have to stay on board
for all events within the competition. Through the modular design of the drivetrain, the unused
power head will be used as ballast to effectively adjust the weight balance to accommodate the
endurance and sprint boat configurations.
D. Propeller
For the optimization of the propeller geometry, OpenProp 3.3.3, an open-source software[3] was
used. OpenProp allows for a parametric study based on user input specifications, such as
required thrust, ship velocity, hub diameter, and water density. The parametric study was
performed for a range of propeller diameters, angular velocities, and number of blades. A
parametric study was performed for a RPM range of 2000 to 5000 RPM and a diameter range of
9 to 12 inches. As one of the team's goals was to ensure cavitation would not occur, a 4-bladed
propeller was selected to increase the developed area. The optimized results of the parametric
study were entered into a single-design analysis tool to iteratively modify the input parameters
until the required propeller power was lower than the available shaft power, which was
calculated to be 18 horsepower at the propeller. The inputs and outputs of the single design
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analysis are shown in Table 4. The finalized was modeled in SolidWorks and can be viewed in
Fig. 7.
Table 4 - Sprint Propeller input and output parameters for final propeller design
Input Parameter Input Value
Number of blades 4
Rotation Speed (RPM) 3400
Diameter (inches) 10
Required Thrust (pound-force) 127
Ship Velocity (mph) 40
Hub Diameter (inches) 2
Output Parameter Output Value
Torque (lb-ft) 27
Power (HP) 17.5
Pitch (in) 12.4
Efficiency 0.74
Figure 7 - Final sprint propeller design modeled in SolidWorks from Table 1 parameters
A simplified stress analysis was performed by utilizing a cantilever beam method[4] to calculate
the maximum stress of a particular cross section of a blade. This method calculates and sums the
stresses due to the propeller thrust, propeller torque, and centrifugal force by using an iterative
method - a more detailed analysis can be viewed in Appendix G.1. Assumptions were required
for the application of the aforementioned forces as point loads on the propeller blade. The results
of the stress analysis can be viewed in Table 5 – there is a sufficient safety factor to compensate
for the assumptions that were required.
11
Table 5 - Results of Stress Analysis for Sprint Propeller
Stress Due to Propeller Thrust 7.679445967 MPa
Stress due to Propeller Torque 58.47948165 MPa
Stress due Centrifugal force 11.10209489 MPa
TOTAL STRESS 77.2610225 MPa
Aluminum 2024 Yield Strength 345 MPa
Safety Factor 4.5
A cavitation analysis was performed by calculating the maximum allowable loading and actual
blade loading.[5] The maximum allowable loading was 11.01 psi, while the actual blade loading
was calculated to be 4 psi, which meant cavitation would not occur during the sprint race.
Specifications on the equations used for this cavitation analysis can be viewed in Appendix G.2.
E. Electrical
Figure 8 - Endurance Electrical Configuration (Left) and Sprint Electrical Configuration (Right)
The endurance configuration consists of a two Sun Power solar panels each connected to a SunSaver
Maximum Power Point Tracker. The MPPTs are then connected to a lead battery array with an output
voltage of 24 V. There is a set of contactors used to bypass the batteries once they become too discharged
to be effective. The battery array delivers power to the Alltrax SPM 48400 motor controller, which
manages the power distributed to the Perm PMG motor. The PMG motor will be powered by 2 Interstate
MPT 93 batteries. A full data sheet of the batteries can be seen in Appendix A. The motor controller is
controlled by a throttle potentiometer that the skipper manually operates. The smart motor control
calculates the efficiency of the motor by measuring the motor voltage, current, and speed, and estimating
the speed using the current measurement and the motor torque constant. It then alerts the skipper whether
to slow down or speed up to improve the efficiency of the boat. A non-contact LEM HASS 50-S Hall
Effect sensor was used to measure the current without power loss. The datasheet is found in Appendix I.4.
An Optek OPB716Z optical sensor, in combination with a black and white striped wheel in the drivetrain,
was used to detect the angular speed of the motor. The output of the sensor drives an external interrupt on
the Arduino, which tallies the number of edges over a set period and obtains the speed. The motor voltage
is measured through a voltage divider and a voltage follower for isolation.
12
For the sprint configuration, two Alltrax SPM 48400 motor controller delivers power to the two Lynch
motors. This time powered by six Odyssey PC 680, with two sets of three in parallel for an array voltage
of 36 V. The potentiometer is used again as a throttle. A secondary contactor is added which can bypass
the motor controllers and connect the motors directly to the batteries, as a last resort to gain extra speed.
A comparison of the two electrical configurations can be seen in Fig. 8.
F. Telemetry
The telemetry system is composed of two subsystems; the on-board subsystem and the on-shore
subsystem. The on-board subsystem’s purpose is to process all of the data collected by the
various sensors and display the relevant data to the skipper. Honeywell CSLA series current
sensors are used to measure the current from the solar panel array, sprint battery array, and
endurance battery array. The voltage across the battery array and solar panel array is measured
using operational amplifiers in a differential attenuating configuration. The motor RPM is
measured using a reflective object sensor by detecting the reflective wavelength of light from a
painted wheel in a specified time and extrapolating based on this data.
All of this data is collected by the ATmega2560 MCU running customized software. A subset of
the collected data is displayed to the skipper using a Matrix Orbital LK204 LCD screen. As
competition guidelines allow, all modules of the telemetry subsystem are powered using an
auxiliary battery. Two MaxStream XStream-PKG-R 900MHz Stand-Alone Radio Modems are
used to transmit data collected by the on-board subsystem to the on-shore subsystem. A laptop
part of the on-shore subsystem collects all data from the on-board subsystem. It displays the data
to the team using a LabVIEW Virtual Instrument and saves the data to an Excel spreadsheet for
future reference.
V. DESIGN EVALUATION
A. Hull
1) Hull Design:
The predicted weight of the surfboard hull from the SolidWorks model was about 55 pounds
with the added estimation of the weight of fiberglass, primer and paint included. Due to different
types of fiberglass needed during construction and the fiberglass that was added to the wooden
inserts for added structural strength, the finalized hull weight is estimated to be about 70 pounds.
The team still felt it achieved its goal of building the most lightweight hull at TCNJ’s current
disposal since the lightest hull in comparison was the 2009 monohybrid hull at 150 pounds.
During construction, marine bow stem construction lines were obtained to correct for those
generated in the model. This process involves using a long thin piece of wood to generate
smooth curves. This was done under advisement because of potential stability issues with the
curves generated in the CAD software. In addition during construction the bow stem was “filled
in” rather than “hollow” as seen in the CAD model. This choice was made to reduce the chance
of water building up in that area as well as simultaneously serving as a place to store sub system
components for different center of flotation configurations. The thickness of the hull was
changed from 5.75 inches to 6 inches because 3 layers of 2” thick foam were glued together.
This design choice was used to ensure the hull had a uniform thickness along the entire length.
Two smaller keels were added in addition to the larger center keel to increase stability.
13
Since construction has been completed, static testing has been completed in a lake on campus.
Photos of this test can be found in Fig. 9 and 10. The test was deemed moderately successful.
The original weight management analysis seen in Appendix E.1 shows the intended locations of
the subsystems on board the hull. This configuration was thought to be sufficient to be able to
shift the weight forward and lift the transom out of the water. Testing conditions proved that
even with most of the subsystems pushed as far forward as possible behind the driver the
transom still had about half an inch to three quarters of an inch to be able to lift out. The test was
successful in that a proper sprint configuration trim angle was found without having to move the
driver and helm positions between events. This added benefit allows for a simple steering system
to be installed and not have to be reconfigured between events. At the time of writing this report
the team is about a week away from hydro dynamically testing the hull in both the sprint and
endurance configurations.
Figure 9- Testing the Endurance Configuration to Try and Achieve Lifting the Transom Out of the Water
14
Figure 10- Testing the Sprint Configuration to Achieve Neutral Trim Angle for Planing Capabilities
2) Hull Materials
The extruded polystyrene foam & white cedar fiber glassed hull was found to be apt in flotation
requirements. The neutral waterline was close to that predicted in the analysis found in Appendix
E.1. In addition, the hull was determined to be stable during the static testing. The skipper was
able to stand and walk around the hull platform with little lateral instability. The use of the 80/20
rails proved to be efficient as well during the static testing. Weight configuration changeovers
took only minutes to shift the center of flotation around. Slight modifications are going to be
made to the dolly to ensure smoother transitions between unloading and loading of the hull.
Overall the hull design to this point in time has been considered a success by the team.
B. Steering
After the design and dimensions were finalized for the helm’s bracket, the bracket was fabricated
using a ¼” thick aluminum plate. Once the plates were completed, they were spot welded before
actually being welded to determine the necessary angle needed to allow the cable to pass
underneath the helm. The bracket for the power head couple was fabricated using a shaft collar
and an aluminum bar. The bar was cut to the proper length and then welded to the shaft collar.
The cable then attaches to both sides of the bar, allowing the cable to pull the motor to the proper
turning direction. Due to a late start fabricating the bracket, the team has yet to completely test
the steering system and brackets. The team plans to test the system on the boat while out of the
water ensuring that all of the parts work as a whole. Once the system is deemed reliable and safe
for the skipper, the team will go out on the water and perform dynamic tests of the system.
15
C. Drivetrain
Accuracy is one of the most important aspects of manufacturing the drivetrain; as a result,
several steps were taken to ensure accuracy. All dimensions were kept to USCS units, to avoid
possible error through conversions. The construction of the drivetrain components was facilitated
through use of a 5-axis CNC machine. Because the accuracy of the hole locations on the power
head plates was of utmost importance, the CNC machine was used, as it provides great accuracy
through its programming. The CNC machine also allowed for the machining of pockets into the
40-tooth pulley to reduce weight. For the components where the CNC machine could not be
used, care was taken to ensure tolerances of at least +/- .001” were maintained. An example of
the completed drivetrain assembly can be seen in Fig. 11.
The current design makes use of a modular gearbox setup in which the
motors and gearbox are swapped between events. This presented a trade-
off; whereas the compound drivetrain facilitated gear reduction changes
between events and reduced overall weight, the modular design allowed
for easier center of flotation adjustment. By making use of two different
gearboxes, the one not in use could be used as ballast. Because each
individual power head is lower in weight than a compound power head,
the resulting weight at the transom of the boat is reduced. This is
especially true in the endurance configuration, where the power head is
about 30lbs, as opposed to the estimated compound drivetrain weight of
90lbs. This reduction in weight at the transom, plus the advantage of the
unused power head to further assist in moving the center of flotation,
allows for improved boat position in the water during the endurance
competition.
When construction of the drivetrain is complete, a few different testing
methods will be used to verify functionality and reliability of the
drivetrain. First, a dry test will be conducted to ensure that the drivetrain
runs, and that the propeller RPM produced matches the design RPM. Dynamic testing will also
be performed before the competition to optimize a few key parameters, including propeller
height, trim angle, and optimal motor speed for each configuration.
D. Propeller
Propellers are traditionally fabricated by a casting process and an additional CNC milling
process to create a good surface finish. TCNJ facilities are not equipped with proper casting
equipment for this process. It was desired to manufacture the propeller in-house to keep costs
low, so it was decided that a CNC process would be used to machine out the propeller from a
solid block of metal. The only practical metal to be machined was an aluminum alloy such as
6061 or 2024 aluminum, as stainless steel and nickel-bronze alloys have a low machinability.
2024 T3 aluminum was selected because of a higher yield strength which would allow for
thinner blade cross sections, while also having a good machinability.
The College of New Jersey's Haas 5-axis CNC mill was used to machine the propeller out of a
single block of 12"x12"x2" 2024 T3 aluminum. The extra material on the outside ring of the
propeller was used as structural supports to provide rigidity and dampen vibrations during the
Figure 11 - Drivetrain assembly
16
machining process. A propeller prototype was first machined in Butterboard ® to validate the g-
code. The prototype highlighted two issues that were corrected for the final machined product -
the blade thickness was globally increased by 0.050 in. to improve rigidity and dampen
machining vibrations, and the hub diameter was reduced to 1.5 in. A side-by-side comparison of
the prototype and final propellers can be viewed in Fig. 12. More detailed steps on the machining
processes can be viewed in Appendix G.3.
Figure 12 – Prototype g-code tested using Butterboard (left) and aluminum propeller after machining (right).
The propeller has been integrated into the lower unit using a clevis pin and a nylock nut. It will
be tested in open water during full system dynamic testing of the boat. The performance of the
propeller will be optimized by fine-tuning the depth of immersion and trim angle at which the
propeller operates. Several trial runs will be conducted to determine acceleration, velocity, and
efficiency values for the propeller - these results will be compared with other available propellers
to determine the best option for use in the competition.
E. Telemetry
The RF module, Hall Effect sensors, and voltage measurements have all been calibrated and
tested to be properly working. Data can be collected and transmitted to the on-shore subsystem.
The on-shore subsystem is able to display the transmitted data and record it for further use.
However further calibration and testing still has to be done before the competition to ensure that
the GPS module and optical sensor are working as intended.
VI. PROJECT MANAGEMENT
A. Team Organization and Responsibility
The College of New Jersey’s 2014 Solar/Electric Boat team is composed of five team members
from two engineering disciplines, mechanical engineering and electrical and computer
engineering. All of the team members worked together building one overall system for their
Senior Project I and II capstone course, while also planning to compete at the 2014 Solar Splash
competition. Two mechanical and one electrical and computer engineering faculty members
17
advise the team. Each member of the team is responsible for different subsystems of the boat,
and is listed below:
Jeff Holman
o Project Manager, Steering System
Joseph Maco
o Telemetry
Jason Pfund
o Propeller Design
Robert Ruff
o Hull Design, Weight Management, Skipper
Michael Schuhlein
o Team Captain, Endurance and Sprint Drivetrain Designs
B. Project Planning and Schedule
The 2014 team decided that a key to developing a successful project would be to properly plan
for it and to create a schedule. The team was first formed in the spring of 2013 and then the first
official meeting was held in the beginning of the 2013 fall semester. During this meeting the
team discussed each of the subsystem designs, initial discussion of integrating everything
together, and the proper planning required to finish on time with a successful project. To help the
team keep on schedule, a Gantt chart was created (Appendix J.1), which outlined schedules for
each subsystem. The team met every Tuesday with the advisors to talk about their designs and
any unforeseen complications.
The team was on schedule throughout the fall, but unfortunately ran into delays starting the
construction over the winter due to late material orders and necessary redesigning’s of the hull’s
bow stem and drivetrain. They put in considerable time with the construction but due to the
nature of building a new hull and two power heads, the testing schedule is pushed back until
May.
C. Financial and fund-raising
To construct a successful boat, the project needed adequate funding. The project manager
created a brochure (Appendix J.2) and letter, which highlighted this year’s new designs, a
breakdown of the budget, a summary of the Solar Splash competition, and a history of past
TCNJ’s Solar Boats and their success. This was sent out to private and corporate companies
seeking for any support, discounts, or donations. This effort proved to be successful because the
team received in full: Formular 250 foam from Owens Corning, Epoxy resin, hardener, primer,
and paint from Interlux, PC680 batteries from Odyssey, and a motor controller from Alltrax Inc.
Even after all these donations, the team still needed additional funds to complete their project.
The team received a budget allocation increase by the TCNJ School of Engineering. The
complete breakdown of the materials budget and travel budget can be seen in Appendix J.3.
18
D. Strategy for Team Continuity and Sustainability
Every year, the TCNJ Solar Boat team is composed of senior students so it is important to pass
on all resources used and any documentation collected to the future years’ teams. This year the
team has included interested underclassmen during the design phase of the boat. The team has
continued using a cloud-based service called Dropbox, which keeps future teams informed about
the past projects’ successes and any recommendations. It is also fortunate that there is a 2015
team already formed and have helped out through the construction phase, allowing them to
understand what needs to be done and to have a better understanding of the scope of the project.
Two of these team members will be attending this year’s competition to gain valuable
experience.
VII. CONCLUSIONS AND RECOMMENDATIONS
A. Strengths
Hull designed and optimized for minimal drag across all events
Frame design allows for quick weight redistribution between races
Optimized high-efficiency sprint propeller
Modular drivetrain design allows for facilitated center of flotation adjustment.
B. Weaknesses
Limited time for boat testing and design changes.
Compound drivetrain design did not work with weight management
C. Future Development
The College of New Jersey plans to continue its involvement in the Solar Splash competition,
and next year’s team has been selected. Important and relevant data and experiences regarding
design, construction, and testing will be shared with the future team, so that they may improve
upon the current team’s shortcomings and the competitiveness of TCNJ’s solar boat entry may
be increased for the following competition.
D. Goals Summary
The team was able to design and construct a surfboard shape hull to effectively compete in the
sprint and endurance configuration. A modular mounting system was implemented that allows
for quick and easy reconfiguration of the center of flotation between races. The sprint propeller
was machined out of a single block of aluminum using a 5-axis CNC milling machine.
Additionally, a motor controller was implemented to run the endurance motor at maximum
efficiency. Based on computer simulations and analysis, the team should be competitive with
other top teams.
E. Recommendations
Research alternate propulsion methods, particularly contra-rotating propellers for
increased endurance efficiency.
Search for software that can incorporate both the propeller and hull analysis
simultaneously
Reduce weight of drivetrain components, and design for a compound configuration
without sacrificing performance.
19
REFERENCES
[1] Savitsky, Daniel. "On the Subject of High-Speed Monohulls." 02 OCT 2003. Society of
Naval Architects and Marine Engineers. 28 Nov 2008
<http://www.sname.org/newsletter/Savitskyreport.pdf>.
[2] Juvinall, Robert C., and Kurt M. Marshek. Machine Component Design.
Singapore: J. Wiley & Sons, 2012. Print.
[3] B.P. Epps, "OpenProp v2.4 Theory Document," MIT Department of Mechanical
Engineering. Technical Report, December 2010.
[4] Carlton, John S. Marine Propellers and Propulsion. Oxford: Butterworth-Heinemann, 2007.
Print.
[5] Gerr, Dave. Propeller handbook: the complete reference for choosing, installing, and
understanding boat propellers. Camden, Me.: International Marine Pub. Co., 1989. Print.
20
Appendix A: Batteries
21
22
Appendix B: Flotation Calculations
The flotation requirement set forth by the Solar Splash competition ensures that the boats will
not sink if completely filled with water. The equation below was used for calculating the
flotation force provided.
Where ρ2g is the specific weight of water and ρ1g is the specific weight of the flotation material,
and V is the volume of the flotation material.
Afterwards the 120% safety factor was added.
Table 6 - Summary of the Flotation Requirement Calculations
As evidenced by Table 3, the chosen size and shape of the hull far exceeds the required
foam to achieve the 6.648 ft3 displacement requirement at a total of 17.31 ft3. Thus, the hull was
deemed to satisfy the safety factor requirement.
23
Appendix C: Proof of Insurance
24
Appendix D: Team Roster
Jeff Holman, Mechanical Engineer, Senior, Steering and Project Management
Joseph Maco, Computer Engineer, Senior, Telemetry
Jason Pfund, Mechanical Engineer, Senior, Propulsion
Robert Ruff, Mechanical Engineer, Senior, Hull, Weight Management, and Skipper
Michael Schuhlein, Mechanical Engineer, Senior, Drivetrain, Team Captain
25
APPENDIX E: HULL ANALYSIS
Appendix E.1
Figure 13 - Comparison of the Full Hull versus Submerged Portion of Hull in the Water
Table 7 - Data Analysis for the Waterline Properties of the Hull
Figure 14 - Comparison Demonstrating the Reduced Drag Force and Vortex Shedding Between Transom In (Left) and
Transom Out (Right)
26
Table 8 - Comparison of Drag Forces between the Proposed Design and Past Years at TCNJ
Figure 15 - Proposed Weight Management Configuration (Endurance Event)
27
Appendix F: Drivetrain
F.1 Timing Belt/Pulley Specifications
28
29
30
31
F.2 LEM-200 D126 Specifications
32
33
F.3 Perm PMG-132 Specification
34
F.4 Bearing Data
35
F.5 ANSI Key Standards
36
Appendix G: Propeller
Appendix G.1: Stress Analysis
The cantilever beam stress analysis was extracted from Marine Propellers and Propulsion
textbook by John Carlton. The equations for the following iterative calculations can be found in
that book.
Table 9- Sprint Propeller Input Parameters for Cantilever Beam Stress Analysis
Shaft power, Ps(W) 13422
RPM 3400
Ship speed (m/s) 17
Wake Taylor Fraction, wt 0.0797
wf 0.980636
D (mm) 250
Radial Position of Examined Stress, r/R 0.1492891
Radial Position of Centroid rc/R, xc 0.4515789
Pitch, p0 (mm) 315
Developed Area (mm^2) 5219.34
Ae/A0=4*Ad/pi*D^2 0.1063275
Bending moment Arm, L (mm)* 7.93
Number of Blades, Z 4
Mechanical efficiency, ηm 0.95
Propeller Open Water Efficiency, ηo 0.733
a=0.7R 0.7
b=0.66R 0.66
density of aluminum (kg/m^3) 2700
*If raked or skewed
distance from center of hub (r/R) 0.2223
volume (mm^3) 43426
mass (kg) 0.12
37
Table 10 - Calculations for Cantilever Beam Stress Analysis
Step
(mm) 2.299368 Interpolated
Ordinate x (m) yp (m) t (m) x (mm) yp (mm) t (mm) x (mm) yp (mm) t (mm)
1 0 0.003302 0 0 3.302 0 0 3.302 0
2 0.000254 0.002794 0.001 0.254 2.794 1.016 2.29936842 2.080126 2.6496
3 0.00127 0.002286 0.002 1.27 2.286 2.032 4.59873684 1.517316 3.566
4 0.00254 0.002032 0.0028 2.54 2.032 2.794 6.89810526 1.058779 4.2538
5 0.004572 0.001524 0.0036 4.572 1.524 3.556 9.19747368 0.826411 4.8868
6 0.007112 0.001016 0.0043 7.112 1.016 4.318 11.4968421 0.517255 5.3247
7 0.009906 0.000762 0.0051 9.906 0.762 5.08 13.7962105 0.208753 5.6332
8 0.013208 0.000254 0.0056 13.208 0.254 5.588 16.0955789 0.031879 5.8101
9 0.01651 0 0.0058 16.51 0 5.842 18.3949474 0 5.842
10 0.020066 0 0.0058 20.066 0 5.842 20.6943158 0 5.7582
11 0.023876 0 0.0053 23.876 0 5.334 22.9936842 0 5.4516
12 0.027432 0.000254 0.0048 27.432 0.254 4.826 25.2930526 0.101218 5.1316
13 0.030734 0.000762 0.0041 30.734 0.762 4.064 27.5924211 0.27868 4.789
14 0.034036 0.001016 0.003 34.036 1.016 3.048 29.8917895 0.632429 4.2584
15 0.03683 0.001778 0.0023 36.83 1.778 2.286 32.1911579 0.874089 3.6156
16 0.039116 0.002286 0.0015 39.116 2.286 1.524 34.4905263 1.139962 2.924
17 0.041148 0.00254 0.0008 41.148 2.54 0.762 36.7898947 1.769088 2.2994
18 0.042672 0.003048 0.0005 42.672 3.048 0.508 39.0892632 2.282658 1.534
19 0.043434 0.003175 0.0001 43.434 3.175 0.127 41.3886316 2.620211 0.7219
20 0.043688 0.003302 0 43.688 3.302 0 43.688
38
Ordinate
Simp Multi
(SM) t*SM (2yp+t)t*SM
[3yp(yp +
t)+t^2]t*SM
1 0.5 0 0 0
2 2 5.299242105 36.08716936 193.6126201
3 1 3.566026316 23.53811975 127.8621893
4 2 8.507663158 54.20563549 297.5106295
5 1 4.88676555 31.95743588 185.9159343
6 2 10.64948988 67.7228224 398.4860293
7 1 5.633246964 34.08538617 199.3723107
8 2 11.62024291 68.25589552 398.7627506
9 1 5.842 34.128964 199.3814077
10 2 11.51644912 66.3143002 381.8526322
11 1 5.451642105 29.72040164 162.024993
12 2 10.26312782 54.74352379 286.5660701
13 1 4.788979757 25.60351442 130.1218286
14 2 8.516712551 47.03963089 233.467142
15 1 3.615643725 19.39366886 89.83485748
16 2 5.848076555 30.43316654 131.2800388
17 1 2.299368421 13.42266401 61.80578729
18 2 3.068052632 18.7131026 87.40817448
19 0.5 0.360947368 2.152082194 9.670570541
20 TOTAL 111.7336769 657.5174837 3574.935966
39
Table 11 - Output of Cantilever Beam Stress Analysis
A 171.2779256 mm^2
Integral of(2yp+t)t 1007.916626 mm^3
Integral of[3yp(yp +
t)+t^2]t 5480.063245 mm^4
Zm 116.869403 mm^3
Centrigual Force (N) 1901.543781
Section Pitch angle (degrees) 1.214459329
Propeller Speed of Advance, Va (m/s) 16.67081137
Stress Due to Propeller Thrust 7.679445967 Mpa
Stress due to Propeller Torque 58.47948165 Mpa
Stress due Centrifugal force 11.10209489 Mpa
TOTAL STRESS 77.2610225 Mpa
Appendix G.2: Cavitation Analysis
Cavitation calculations were completed with the use of David Gerr's Propeller Handbook.
where, Va = Speed of water at propeller, in knots
Ft = depth of immersion of the propeller shaft, in feet
where, SHP = shaft horsepower at the propeller
e = propeller efficiency in open water
Ad = developed area of propeller blades, in square inches
40
Appendix G.3: Manufacturing
Figure 16 - Surface finish of the roughing pass by the CNC mill. A 1/2" end mill was used to quickly remove large
amounts of material.
Figure 17 - FInishing pass by the CNC mill. Foam plugs were used to dampen blade vibrations caused by the mill. A
water-soluble oil coolant was used.
41
Figure 18 - Machined surface finish resulted in small lateral ridges.
Figure 19 - Fine sand paper was used to smooth out the ridges to improve fluid flow characteristics.
42
Figure 20 – Aft view of the final machined sprint propeller.
Figure 21 - View of the sprint propeller mounted on the lower unit. This will attach to the drive shaft of the drivetrain.
43
Appendix H: Eletrical Systems
Appendix H.1: SCHOTT 240 W Solar Panel Data Sheet
44
45
Appendix H.2: Morningstar SunSaver MPPT
46
47
Appendix I: Telemetry
Appendix I.1: XStream-PKG-R RF Module
48
49
50
51
52
53
Appendix I.2: L01Z600S05 600A Hall Effect Current Sensor
54
55
Appendix I.3: CSLA2CD 72A Hall Effect Sensor Data Sheet
56
57
Appendix I.4: OPB715Z Optical Sensor
58
Appendix I.5: EM-406A GPS Module
59
60
61
62
Appendix I.6: Arduino Mega Datasheet
63
Power
The Arduino Mega can be powered via the USB connection or with an external power supply. The power
source is selected automatically.
External (non·USB) power can come either from an AC·to·DC adapter (wall·wart) or battery. The
adapter can be connected by plugging a 2.1mm center·positive plug into the board's power jack. Leads
from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector.
The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the
sV pin may supply less than five volts and the board may be unstable. !fusing more than 12V, the
voltage regulator may overheat and damage the board. The recommended range is 7 to 12volts.
The Mega2s6o differs from all preceding boards in that it does not use the FTDI USB·to·serial driver chip.
Instead, it features the ATmega16U2 (ATmega8U2 in the revision 1and revision 2 boards) programmed
as a USB·to·serial converter.
Revision 2 of the Mega2s6o board has a resistor pulling the 8U2 HWB line to ground, making it easier to
put into DFU mode.
Revision 3of the board has the following new features:
+ 1.0pinout: added SDA and SCL pins that are near to the AREF pin and two other new pins placed near
to the RESET pin, the IOREF that allow the shields to adapt to the voltage provided from the board. In
future, shields will be compatible both with the board that use the AVR, which operate with sV and with
the Arduino Due that operate with 3.3V. The second one is a not connected pin, that is reserved for
future purposes.
+ Stronger RESET circuit.
+ Atmega 16U2replace the 8U2.
The power pins are as follows:
+ VIN. The input voltage to the Arduino board when it's using an external power source (as opposed to s
volts from the USB connection or other regulated power source). You can supply voltage through this
pin, or, if supplying voltage via the power jack, access it through this pin.
+ sV. The regulated power supply used to power the microcontroller and other components on the
board. This can come either from VIN via an on·board regulator, or be supplied by USB or another
regulated sV supply.
64
+ 3V3. A 3·3 volt supply generated by the on·board regulator. Maximum current draw is somA.
+ GND. Ground pins.
Memory
The ATmega2s6o has 256 KB of flash memory for storing code (of which 8KB is used for the bootloader),
8KB ofSRAM and 4 KB of EEPROM (which can be read and written with the EEPROM library).
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Appendix I.7: Matrix Orbital LK204-25-WB Data Sheet
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Appendix J: Project Management
Appendix J.1: Team Gantt Chart
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Appendix J.2: Sponsorship Brochure
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Appendix J.3: Materials and Travel Budget
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