Project Proposal and Feasibility Study - Calvin College€¦ ·  · 2015-05-15Project Proposal and Feasibility Study ... 3 Project Management 3.1 Project Breakdown ... A-Arm Stress

Project Proposal and Feasibility Study

Team 6: Josh Vanderbyl

Zak DeVries Nico Ourensma

Ryan DeMeester

Calvin College December 8th, 2014

Advisor: Professor Ned Nielsen

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©2014

Josh Vanderbyl, Zak DeVries, Nico Ourensma, Ryan DeMeester and Calvin College

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Executive Summary This report details the research and design of the Jet Blade. The Jet Blade is a new and unique

personal watercraft. The goal of Team 6 is to design a personal watercraft (PWC) that will

provide the user with an unparalleled experience in water sports activities. The Jet Blade is a

single rider personal watercraft that is stable yet agile. The Jet Blade will incorporate a three-ski

design that utilizes two skis in the front of the craft and one ski in the rear. These skis are

located in spaced relation below an aluminum hull and operate to hydro-dynamically lift the Jet

Blade to a cruise position by relative water flow upon the undersides of the skis. The rear ski is

attached to a horizontal jet pump that is powered by a 650cc water-cooled engine. The front

suspension implements an Active Tilt steering design that will allow for the agility. Team 6, also

known as Team Jet Blade, has chosen this project for their senior design capstone project. The

conclusion of the feasibility study is that the manufacturing and creation of the Jet Blade will be

feasible.

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Table of Contents Executive Summary ........................................................................................................................ 2 Table of Tables ............................................................................................................................... 5 Table of Figures............................................................................................................................... 6 1 Introduction

1.1 The Project .................................................................................................................. 7 1.2 Design Norms .............................................................................................................. 7

1.2.1 Transparency ............................................................................................... 7 1.2.2 Integrity........................................................................................................ 7 1.2.3 Trust ............................................................................................................ 7

1.3 The Team ..................................................................................................................... 8 1.3.1 Team Roles .................................................................................................. 9

2 Requirements 2.1 Safety........................................................................................................................... 9 2.2 Operating Conditions................................................................................................... 9 2.3 Functionality ............................................................................................................. 10 2.4 Regulations ............................................................................................................... 10

3 Project Management 3.1 Project Breakdown..................................................................................................... 10

3.1.1 Hull ............................................................................................................ 10 3.1.2 Skis............................................................................................................. 11 3.1.3 Suspension and Steering............................................................................ 11 3.1.4 Propulsion ................................................................................................. 11 3.1.5 Control Systems......................................................................................... 11

3.2 Schedule..................................................................................................................... 11 3.2.1 Task List...................................................................................................... 11

3.3 Budget........................................................................................................................ 12 4 Research

4.1 Hull Research ............................................................................................................ 12 4.2 Ski Research .............................................................................................................. 13 4.3 Tilt Suspension Research ........................................................................................... 14 4.4 Jet Pump Research .................................................................................................... 16 4.5 Motor Research ......................................................................................................... 17

5 Design Process 5.1 Design Alternatives ................................................................................................... 17

5.1.1 Hull ............................................................................................................ 17 5.1.2 Ski .............................................................................................................. 17 5.1.3 Suspension and Steering ........................................................................... 18 5.1.4 Propulsion ................................................................................................. 19

5.2 Design Decisions ............................................................................................. .......... 19 5.2.1 Hull ............................................................................................................ 19 5.2.2 Ski .............................................................................................................. 20 5.2.3 Suspension/Steering ................................................................................. 20 5.2.4 Propulsion ................................................................................................. 20 5.2.5 Control Systems ........................................................................................ 21

5.3 Design ....................................................................................................................... 21

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5.3.1 Hull ............................................................................................................ 21 5.3.2 Ski .............................................................................................................. 23 5.3.3 Suspension and Steering …........................................................................ 27 5.3.4 Propulsion.................................................................................................. 30 5.3.5 Complete Design ....................................................................................... 30

6 Testing 6.1 Safety ........................................................................................................................ 32

6.2 Launch Capabilities ................................................................................................... 32 6.3 Strength .................................................................................................................... 33 6.4 Performance and Handling ....................................................................................... 33

7 Business Plan 7.1 Market Competition .................................................................................................. 34 7.2 Break-even Analysis................................................................................................... 34

8 Conclusion ................................................................................................................................. 35 9 Acknowledgements.................................................................................................................... 35 10 Bibliography ............................................................................................................................ 35 Appendix A: Project Gantt Chart .................................................................................................. 36 Appendix B: EES Calculations ....................................................................................................... 38 Appendix C: FEA Analysis ……........................................................................................................ 41

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Table of Tables Table 1: Tasks for design and manufacturing of the Jet Blade ..................................................... 12

Table 2: Estimated Production Material Costs ............................................................................. 12

Table 3: Input Values ................................................................................................................... 25 Table 3: Market Competition ....................................................................................................... 34

Table 4: Production Costs ............................................................................................................ 34

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Table of Figures Figure 1: Team Picture ................................................................................................................... 8 Figure 2: WetBike Schematic ....................................................................................................... 13

Figure 3: Pressure Distribution of a Flat Planing Surface ............................................................. 14

Figure 4: Model of Swayspension ................................................................................................ 15

Figure 5: Tilting Motor Works ...................................................................................................... 15

Figure 6: Jet Pump Schematic ...................................................................................................... 16

Figure 7: Motor and Pump Assembly ........................................................................................... 17 Figure 8: Hull CAD Model ............................................................................................................. 21 Figure 9: Bottom Hull with Frame ................................................................................................ 22 Figure 10: Bottom Hull with Frame FEA ....................................................................................... 22

Figure 11: Jet Blade Float Height ................................................................................................. 23

Figure 12: Front Ski CAD Model ................................................................................................... 24

Figure 13: Rear Ski CAD Model ……............................................................................................... 24

Figure 14: Definition of Inputs ..................................................................................................... 25

Figure 15: Results of Savitsky Procedure ..................................................................................... 26

Figure 16: Jet Blade During Planing Process ................................................................................ 26 Figure 17: WetBike During Planing Process ................................................................................. 26

Figure 18: Active Tilt Suspension ................................................................................................. 27 Figure 19: Active Tilt – Right Turn ................................................................................................ 28 Figure 20: Active Tilt – Straight .................................................................................................... 28

Figure 21: Active Tilt – Left Turn .................................................................................................. 28

Figure 22: Compressed Suspension ............................................................................................. 29

Figure 23: Complete CAD Model .................................................................................................. 30

Figure 24: Complete Model – Front View .................................................................................... 31

Figure 25: Complete Model – Right Turn ..................................................................................... 31

Figure 26: Complete Model – Left Turn ....................................................................................... 32

Figure 27: A-Arm Force Loading ................................................................................................... 41

Figure 28: A-Arm Stress Results ................................................................................................... 41 Figure 29: A-Arm Displacement Results ....................................................................................... 41 Figure 30: Yoke Force Loading ..................................................................................................... 42 Figure 31: Yoke Stress Results ……………........................................................................................ 42 Figure 32: Yoke Displacement Results …....................................................................................... 42 Figure 33: T Force Loading ........................................................................................................... 43 Figure 34: T Stress Results ……………………...................................................................................... 43 Figure 35: T Displacement Results ............................................................................................... 43

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1 Introduction 1.1 The Project Team 6, is designing a new and unique personal watercraft. The goal of Team 6 is to design a

personal watercraft (PWC) that will provide the user with an unparalleled experience in water

sports activities. Jet Blade is designed to be safe, user friendly, aesthetically pleasing and

exhilarating to ride. The design incorporates an aluminum hull, suspension design, and skis that

resemble similar structure to a snowmobile. However, the front suspension implements a tilt

steering design providing riders with a motorcycle feel on the water, while still maintaining

stability. This will allow for a wide variety of riders to enjoy the performance of the Jet

Blade. Cost, strength, quality of design and manufacturability were all considered in order to

optimize the design of Jet Blade.

1.2 Design Norms

1.2.1 Transparency The Jet Blade must be designed to be easy to operate and its functions must be clear to the

user. In order for the Jet Blade to be successful it must be able to be used safely and easily by a

range of users. Maintenance and problem diagnosis of the machine must be clearly identified

and obvious to the user.

1.2.2 Integrity Honesty and decency must be maintained in the design, manufacturing, and presentation of the

Jet Blade. The Jet Blade will be easy to operate and intuitive for all riders.

1.2.3 Trust In order to meet the design norm of trust, the Jet Blade must be strong and reliable. It must be

able to endure sustained use and maintain performance. The Jet Blade needs to provide an

exhilarating experience while maintaining a feeling of safety for the rider.

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1.3 The Team

Figure 1: Team Picture

The team consists of Josh Vanderbyl, Zak DeVries, Nico Ourensma, and Ryan DeMeester. Each

member of the team is part of the mechanical concentration of the engineering program at

Calvin College. The team shares great interest in the outdoors and water activates. Our passions

collided with our skills when the Jet Blade project was established.

Josh Vanderbyl: A Southern California native, Josh grew up in Beaumont, California. While

studying at Calvin College, Josh has had internships at Kerry Ingredients & Flavors as well as

Shape Corporation. At these internships Josh gained industry knowledge in project management

and lean manufacturing as well as developed skills in Solidworks CAD design.

Zak DeVries: Growing up in Byron Center, Michigan Zak began his engineering career at Lacks

Trim Systems where he learned the basics of lean production and the importance of continuous

improvement projects. He is currently working at Progressive Surface where he has developed

problem solving abilities and gained skills in Solidworks CAD design.

Nico Ourensma: Originally from Lake City, Iowa, Nico started his engineering design at The

Cardinal Group where he gained experience in Autodesk Inventor CAD design. He has more

recently held a position at Woodward, Inc. where he was involved in the testing of aircraft

turbine engine components.

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Ryan DeMeester: Proudly from Pasadena, California Ryan has had great internship experience in

west Michigan. From working on quality control for honeycomb materials at Plascore, to

performing time analysis studies at DeWys Manufacturing, Ryan has a wide variety of

experience that is the essential foundation of his problem solving and engineering skills.

1.3.1 Team Roles

Josh Vanderbyl: Josh is responsible for the design and manufacturing of the top hull and the

front and rear skis.

Zak DeVries: Zak is responsible for the design and modeling of the suspension, the bottom hull,

and the tilt steering of the Jet Blade.

Nico Ourensma: Nico is responsible for the design and manufacturing of the top hull, seat,

suspension, tilt steering, and the controls for the Jet Blade.

Ryan DeMeester: Ryan is responsible for assisting with design and manufacturing of the bottom

hull, the seat, and the front and rear skis. He is also in charge of designing and updating the

team website.

2 Requirements 2.1 Safety As with any recreational vehicle, user safety is very important. Riders need to feel safe and

secure while riding the Jet Blade. The hull must be water tight and dependably buoyant. It must

feel stable once on plane and be easily controlled so collisions can be avoided. Most personal

watercraft (PWC) injuries result from running into docks, other watercraft, or other objects. For

this reason, maneuverability is very important. As with any personal watercraft, a kill switch

must be implemented to prevent a runaway vehicle scenario.

2.2 Operating Conditions The Jet Blade is designed to operate optimally in flat water conditions. It is on the other hand

engineered to operate in moderate to rough conditions while maintaining stability. The

watercraft's front Active Tilt suspension is able to absorb waves and the front skis are designed

to cut through them in order to provide the operator with a smooth ride. The Jet Blade is

designed for use on small inland lakes where waves should not exceed 1-2' in amplitude. Like

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most watercraft it is a seasonal vehicle. It is able to operating in water temperatures down to

32oF, however this is well below comfortable riding temperatures. Conversely, the liquid cooled

650cc engine allows the Jet Blade to stay cool even on the hottest summer days, operating in

water temperatures up to 90oF.

2.3 Functionality The Jet Blade is a single rider personal watercraft that is stable yet agile. The function of the Jet

Blade is to be a recreational vehicle used on water. The three-ski design utilizes two skis in the

front of the craft and one ski in the rear. These skis are located in spaced relation below an

aluminum hull and operate to hydro-dynamically lift the Jet Blade to a cruise position by relative

water flow upon the undersides of the skis. This will allow the rider to have a controlled and

comfortable ride at cruising speeds. The front suspension implements a tilt steering design that

will allow for the agility. The Jet Blade is designed to be trailered, loaded, and unloaded with

only one person.

2.4 Regulations The Jet Blade must be registered by the State of Michigan. It must also have current registration

stickers in order to be operated in any body of water in Michigan. The Jet Blade is designed to

be usable by a wide variety of rides. In the State of Michigan any rider 14 and older with a

boater’s safety license are able to operate the Jet Blade.

3 Project Management 3.1 Project Breakdown The project is broken down into five categories, each of which have a significant role in the final

outcome of the design. The five categories of the project include the hull, skis, suspension and

steering system, propulsion system, and the control system. Each member of the team is

responsible for certain categories and will have authority in the design and manufacturing. The

whole team is working together to make sure each is done well.

3.1.1 Hull The hull is the foundation of the Jet Blade. It needs to be strong and rigid enough to withstand

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the weight of the rider and engine while remaining light enough to provide significant

performance. The hull also needs to provide enough buoyancy to keep the Jet Blade and the

rider comfortably floating in the water.

3.1.2 Skis The three ski design utilizes two skis in the front of the craft and one ski in the rear. The Jet

Blade, when being operated, begins with the skis and a portion of the craft submerged. As the

speed increases the skis begin to plane until the Jet Blade is completely out of the water and

riding solely on the skis. While the skis are submerged there is little control of the vehicle. This is

why it is important to design the skis large enough so that the Jet Blade can plane quickly.

3.1.3 Suspension and Steering Conventional personal watercraft rely on a directional water jet to steer. Jet Blade is unique in

that the jet is fixed and steering is accomplished by turning the front skis. In order to achieve

maximum turning performance, both skis must remain in contact with the water at all

times. This requires the implementation of a tilt suspension system.

3.1.4 Propulsion System Similar to most personal watercraft, Jet Blade will implement a jet pump for thrust. A right

angle gear box connects the impeller to a vertical-shaft engine. As the engine and pump

assembly are the largest components, the Jet Blade will essentially be built around the

propulsion system.

3.1.5 Control Systems Certain control systems are required for basic operation and safety. These include start and

stop switches, an electronic choke, and a kill switch. In addition, certain gauges will be

implemented to monitor fuel level, vehicle speed, and engine RPM.

3.2 Schedule

3.2.1 Task List The table below lists and describes the tasks and steps necessary for the completion of the

project. Many of the tasks are defined in greater detail in later sections of the report.

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Table 1: Tasks for design and manufacturing of the Jet Blade

Task Description

Project Management Define project goals and determine main tasks

Gantt Chart Estimate time for tasks and define schedule

Research Research components and aspects of design

Conceptual Drawings and Physical Models

Preliminary drawings and models of components

Budgeting Estimate rough cost of project

Design Alternatives Determine best alternative

Initial Design Initial drawings and model of project

PPFS Report Report stating the feasibility of the project

Final Design Final drawings and model of project Manufacturing and Creation Construction of the project

Testing Final in water testing will be done on the product

Final Report Report containing all information of the product

3.3 Budget Table 2 which may be seen below shows estimated costs for materials and equipment needed

to build a prototype Jet Blade.

Table 2: Estimated Production Material Costs

Component Estimated Cost

Pump Assembly, 650cc Engine (Wet Bike)

$225.00

Starter $60.00 Gas Tank $20.00 Trigger Throttle $30.00 Throttle Cable $25.00 Ignition Switch $50.00 Gauges $100.00 Handle Bars $35.00 Shocks $120.00 Aluminum $600.00 Seat $25.00 Foam $40.00 Hardware $50.00 Estimated Total Cost $1,380.00

4 Research 4.1 Hull Research In order to get a better understanding of the hull design for the Jet Blade. Different types of

hulls were researched. Specifically the differences between fiberglass and aluminum hull

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construction. It was found that there are varying opinions on which material is best suited for

boat hull construction. Many favored fiberglass because it was strong, highly moldable, and

provided a quieter ride on the water. While others preferred aluminum because it is cheap, light

and long lasting and provides a better resistance to impact. If a fiberglass boat crashes into

something it is very expensive to fix and difficult to hide the repairs. While with an aluminum

hull the dents can simply be pulled out or a new pieces welded in and ground flush.

The size of the hull was also researched and it was found that the draft of the hull at rest is a

function of the volume of the hull and the mass it is supporting. Meaning the larger and lighter a

boat is, the shallower water it can float in. While the Jet Blade will have a lot going on under the

water line, it is still important to consider the overall draft of the Jet Blade, weighted and un-

weighted.

4.2 Ski Research Since Jet Blade's use of skis is unique to most other watercraft it was difficult to find material to

research ski design. The 1979 WetBike is the only other watercraft that hydroplanes on the

water while implementing skis so it was studied in order to perceive possible design issues that

would be faced.

Figure 2: WetBike Schematic [1]

The ability of the ski's to provide lift and raise the Jet Blade up and on top of the water was

crucial. In order to better understand the physics involved with ski's creating lift, research was

done into water skiing, snow skiing and finally boat planing. It was found that the physics

involved with a boat planing on top of the water was most similar to the physics involved in the

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ski design of the Jet Blade. Daniel Savitsky performed in depth research into the physics that are

involved in the planing of boats. Through this research he developed equation for the forces

involved for the planing of flat bottomed boats, as well as boats with V - shaped hulls. A

simplified model of the physics involved can be seen in Figure 3: Pressure Distribution of a Flat

Planing Surface.

Figure 3: Pressure Distribution of a Flat Planing Surface [2].

Savitsky used his theory to develop equations that can be used to calculate power requirements

for various shapes and sizes of boats, as well as hull design and shape. He was also able to

incorporate trim angle (tilting angle) as well as the effects of rudders, trim tabs, and drive shafts.

It is the combination between trim angle, surface area, and shape that were most relevant to

the design of the Jet Blade.

4.3 Tilt Suspension Research It was important for the suspension system of Jet Blade to be able to tilt. Tilting suspension

systems were researched in order to develop an understanding for the kinematics involved. The

initial system that was studied was Swayspension, which was a senior design project from Calvin

College's class of 2013. This report provided the basic kinematic system that was used for the

design of the Jet Blades suspension. However, the Swayspension design incorporated a passive

tilting suspension system as seen in Figure 4.

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Figure 4: Model of Swayspension [3]

Passive means that the tilting motion of the vehicle was a function of the inertia generated from

cornering. While this suspension system was effective for Swayspension, it cannot be practically

applied to Jet Blade. The suspension design of Swayspension was a complicated design that

involved a primary and a secondary suspension system. This level of complexity was not

required for a PWC suspension system.

Tilting Motor Works was another suspensions system that was researched. This tilting

suspension design is similar to the tilting suspension that is being designed for Jet Blade. This

design can be referenced in Figure 5.

Figure 5: Tilting Motor Works [4]

While the initial geometry design for the suspension was based upon Swayspension. The shock

absorber configuration of the Tilting Motor Works design inspired the design for Jet Blades

suspension system. The Tilting Motor Works design and the Swayspension design are both

passive tilt suspension systems. This means that there is no user input that mechanically

controls the tilting of the wheels. The Tilting Motor Works system works because the gyroscopic

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effects of spinning wheels assist in the righting of the vehicle. However, this effect is lost when

the skis are substituted for wheels. Therefore, a mechanical input will be necessary in order for

Jet Blade to right itself after a lean has been initiated.

From the research that was performed, a system that incorporates an active tilting mechanism

was not found. All tilting systems are initiated by the rider shifting their weight and the

gyroscopic effects of the turning wheels, or straightening of the wheels. Therefore, an original

Active Tilt suspension system was designed for Jet Blade, while the basic geometries of the

system were based on previous designs, the mechanism that actively controls the roll of the Jet

Blade has never been implemented.

4.4 Jet Pump Research The jet pump assembly necessary for this project needed to incorporate a right angle torque

converter in order for the pump to be located well below the hull. With the design complexity

and expense of fabricating a jet pump, it was decided that it would be purchased. As seen in

Figure 6, the pump uses two gears which are oriented perpendicular to each other. The

vertically aligned gear is connected to a shaft that rotates on two sets of bearings. The end of

the shaft is connected to a propeller and the convex shape of the pump assembly causes the

thrust. Figure 7 shows the motor and pump assembly that will be used to propel the Jet Blade.

Figure 6: Jet Pump Schematic [1]

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Figure 7: Motor and Pump Assembly

4.5 Motor Research The motor to be used for the Jet Blade is a 50 HP Suzuki two stroke from a 1979 WetBike. As

shown in the figure above, the WetBike motor and pump assembly was used because of the

compact design and integration.

5 Design Process 5.1 Design Alternatives

5.1.1 Hull Material selection was the main source of design alternatives for the hull of the Jet

Blade. Fiberglass is by far the most popular hull material in the personal watercraft

industry. While it is durable and strong, it is also quite heavy and proper fabrication can be

difficult and expensive. A second material option is steel. Due its weight and rusting

characteristics, it is clear that steel is not ideal for aquatic operating conditions. A third material

alternative was aluminum. Aluminum has a higher strength to weight ratio than fiberglass and

doesn't corrode like steel.

5.1.2 Skis There two different ski configurations that were considered for the Jet Blade. The first

alternative was a two-ski design which incorporated a single ski in the front and rear. An

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advantage to this design is the gained agility by having a single ski in the front when turning.

This design would imitate the motion of riding a motorcycle. The second option considered

involved two skis in the front and a single at the rear. This configuration enhances the stability

of craft while maintaining agility.

5.1.3 Suspension and Steering There were a variety of different suspension systems that were considered for the connection of

the front skis to the hull of the Jet Blade.

Alternative 1: Rigid connection

A typical watercraft or PWC does not incorporate any type of a suspension system. However,

some high-end PWCs do incorporate suspension systems, yet this is very rare. The rigid

connection would be the simplest method of connecting the front skis to the hull. This option

would also be the lightest and cheapest, but it would provide the worst performance.

With a rigid suspension the Jet Blade would lose handling capabilities. It would be difficult to go

around a corner without flipping over or an excessive amount of counterbalance would be

demanded from the rider. The rigid suspension system will also cause a very rough ride when

the water is choppy. There is also a risk that if the water is too choppy that the skis would

plunge through a wave if they are not allowed to deflect with respect to the hull.

Alternative 2: Double Wishbone

The double wishbone suspension design would allow for the deflection of the skis when rough

water is encountered. This will give the Jet Blade a smoother ride over rough water and will also

reduce the smack of the ski's landing on the water after a jump. The double wishbone

suspension would also allow the skis to deflect and reduce the possibility of the skis getting

pushed down under the water. However, the double wish bone design is limited in its ability to

provide acceptable handling performance. The double wish bone design has the same

shortcomings as a ridged connection. The Jet Blade would be likely to tip over when cornering,

or the rider would have to aggressively counterbalance the Jet Blade around a corner. With the

goal of the Jet Blade to be a user-friendly vehicle that provides an unparalleled experience on

the water, the double wish bone suspension did not fulfill all of the requirements needed to

accomplish the goal.

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Alternative 3: Tilting Suspension System

A titling suspension system was the third type of suspension analyzed for the Jet Blade design.

This type of suspension incorporates the double wishbone suspension system but also allows

the Jet Blade to tilt as it corners. The incorporation of the double wishbone suspension will

allow the skis to deflect as they encounter rough water. This will provide a smoother ride.

However, the tiling motion will allow the Jet Blade to lean into the corner; lowering the center

of gravity and reduce the amount of counterbalance required by the rider. This will also increase

the maneuverability of the Jet Blade at higher speeds, by tilting as it turns both of the front skis

will be able to maintain a greater surface area of contact. By increasing the surface area of

contact of the front skis the Jet Blade will be able to plane and turn at lower speeds and will feel

more responsive at higher speeds. However, the tilting suspension system is the most

expensive and complicated design of the three alternatives. Yet, it is the only alternative to

provide both a comfortable ride and the maneuverability and performance that is desired.

5.1.4 Propulsion

When it comes to propulsion, there are two main alternatives used by watercraft. This first is a

common propeller. Propellers are the standard for boats of all sizes and have been used for

many years. The other propulsion option is a jet pump. Jet pumps use an impeller to force

water through a nozzle to achieve thrust. Jet pumps are the standard for PWCs and are safer for

users in the water due to their enclosed nature.

5.2 Design Decisions

5.2.1 Hull Aluminum was selected as the material of choice for the hull of the Jet Blade. Aluminum

provides superior corrosion resistance to steel. It is lighter that fiberglass and steel. There is not

a large difference in price between steel and aluminum, but aluminum is significantly cheaper

than fiberglass. While fiberglass provides greater flexibility in the shape of the hull, the

manufacturing of the hull will be much easier if aluminum is used instead of fiberglass.

Therefore aluminum was selected as the material for the hull because it is cheap, light and easy

to work with.

The initial design of the hull only included an 1/8" aluminum sheeting shell that would be

connected to the engine and pump. After doing FEA on the bottom panel that connected to the

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engine and pump, the weight of the Jet Blade and rider alone gave a stress that was higher than

the yield strength of 6061 aluminum. A second design that included an interior frame was

needed to help distribute the load of the rider and the Jet Blade.

5.2.2 Skis It was decided that the Jet Blade would implement three skis in its design, with two skis in the

front and one ski in the back. The alternative design would be to implement a two ski design,

with one ski in the front and one ski in the back. The three ski design was decided upon because

it was determined it would increase the maneuverability of the PWC. With two skis located in

the front it would then allow for two edges to be in contact with the water while turning at all

times giving more control over a one ski design. Having two skis on the Jet Blade will allow for

increased stability and allow for easier use for the end user.

5.2.3 Suspension and Steering An Active Tilt suspension system was chosen for the Jet Blade because it provides the best

combination of stability, maneuverability, and comfort. The Active Tilt steering and suspension

design will feature a suspension system that is able to tilt +/- 35o from vertical. The tilting

motion of the Jet Blade is controlled by handle bar position. This means that the farther the

handlebars are turned, the further the Jet Blade will tilt. This active system was incorporated

due to the lack of gyroscopic effects cause by the rotational inertia of tires.

The Active Tilt suspension system also incorporates two shock absorbers that are connected to a

double wishbone suspension system. This will allow for the ski deflection and provide a

smoother more consistent ride. The steering system is comprised of a standard ball joint and tie

rod design that is used on most popular snowmobiles.

5.2.4 Propulsion The propulsion system used by the Wet Bike was chosen for the Jet Blade for several

reasons. First, at 50 HP, the motor will provide ample power to propel the craft and was built

for use in marine applications. Second, the integrated right angle gearbox is necessary in order

to achieve the required motor and pump arrangement. The downward facing intake on the jet

pump is ideal because it will allow the proper flow of water while the skis are on plane.

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5.2.5 Control system Basic engine start and stop controls similar to other PWCs will be used on the Jet Blade. In

addition, an electronic choke will be implemented along with a kill switch lanyard for safety. A

thumb throttle will be used to allow better control while maneuvering.

5.3 Design

5.3.1 Hull A model of the Hull can be seen in Figure 8.

Figure 8: Hull CAD Model

This hull is designed from 1/8" aluminum sheeting. It is fully welded together in order to provide

a strong and water tight hull. In order to distribute the load of a rider and the Jet Blade an

interior frame is necessary to reduce the stress on the bottom plate. The figure below shows the

bottom portion of the frame.

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Figure 9: Bottom Hull with Frame

The pump and engine mount between the bottom panel of the hull and seal with a rubber

gasket that was used on the purchased WetBike. The gasket has a 0.59” spacing between the

engine and pump assembly which sealed between the original Wet Bike hull. The thickness of

our base plate for the hull is 0.125” and combined with the addition frame will add to the

necessary 0.59” to create a watertight seal. The frame will be constructed out of 0.5” thick

aluminum square tubing. The frame will continue up the side walls and wrap around to connect

under the seat. The frame will continue up the front panels shown in Figure 9 above to connect

to the suspension and steering column. The load will be distributed to where the pump and

engine connect to the bottom panel. This is why the FEA was done only on the bottom portion

of the frame. The FEA of the frame with a 400 lbf load distributed along the outer members of

the frame resulted in a maximum stress of 463 psi.

Figure 10: Bottom Hull with Frame FEA

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The buoyancy force needed to keep a craft afloat is equal to the weight of the craft. The volume

of water displaced by the Jet Blade changes with its profile. The volume at four major cross

sections were taken and averaged. This was then used to determine an effective volume of each

section. The calculations for the buoyancy force are in Appendix B. Figure 11 shows where the

Jet Blade sits at rest relative to the waterline with no rider and then with a 250 lb rider. With no

rider the jet blade sits 15 inches into the water relative to the bottom panel. With the assumed

250 lb rider the Jet Blade sits 21 inches into the water.

Figure 11: Jet Blade Float Height

The addition of the frame attached to the outer hull shows a feasibility in the strength of the

hull design. With FEA the bottom hull has been proven to withstand the weight of the Jet Blade

and rider with a high safety factor. The buoyancy calculations show the feasibility of the current

design and it will be able to float at rest with a 250 lb rider.

5.3.2 Skis Design issues to address include avoiding air that becomes entrapped in the water which then

reaches the pump assembly. If entrapped air reaches the pump it causes a significant decrease

in efficiency and performance. Since the front of the Jet Blade will be riding on two skis it is

hopeful that the turbulence created from the skis will be on either side of the back ski and

therefore not be a factor on introducing entrapped air into the pump. The rear ski will need to

be designed with certain features that help transfer the entrapped air out and away from the

intake. The skis will need to be designed with a certain angle of inclination in order to be certain

that the PWC is able to plane on the water once being submerged. The design of the skis will

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need to accommodate for maneuverability and still maintaining a smooth ride while operating

in a straight line. The skis will need to have enough bottom surface are to ensure the Jet Blade is

able to plane on top of the water. Calculations will need to be made in order to determine how

much of a load will be placed on the front and back skis. The skis will need to be designed in

conjunction with the Active Tilt suspension employed on the WetBike. Computer models of the

skis may be seen below in Figure 12 and Figure 13. The front skis featured a design with ribs

coming down on either side in order to achieve the cutting action desired. The angle at which

these ribs came down at in relation to horizontal section of the ski was calculated to be 120

degrees. This angle was chosen so that when the Active Tilt suspension is leaned to the left or

right the rib of the skis will not be back cutting into the water.

Figure 12: Front Ski CAD Model

Figure 13: Rear Ski CAD Model

In order to prove the feasibility of the ski design plaining calculations were completed to make

sure that the ski would indeed rise out of the water and plane on the surface. Savitsky’s planing

equations were used in order determine the correct ski design. A program was located that

incorporated the parameters required for Savitsky’s equations and produced a graphical

representations of the ski’s performance. These equations were created to for boat hulls and

not skis, so some assumptions had to be made. First, was that the ski could be modeled as the

hull of a flat bottomed boat. Second, was that the center of gravity for the entire Jet Blade was

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also the center of mass for the same flat bottomed boat. The mass of a 250 lb rider was also

included. This essentially modeled the Jet Blade as a tall front heavy boat with a small hull as its

foot print. The parameters shown in Table 3 were then inserted into the program and Figure 15

was generated.

Figure 14: Definition of Inputs [5].

Table 3: Input Values

Variable Value Units Displacement 272 kg Longitudinal Distance of Center of Gravity from Transom

0.95 m

Vertical Distance From Center of Gravity to Transom

0.61 m

Beam of Hull 0.63 m Angle of Dead Rise 0 (Flat Bottomed Hull) Degrees Distance Offset from Center of Gravity

0.46 m

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Figure 15: Results of Savitsky Procedures

During this analysis it was determined that the initial beam (b) or width of the ski was not wide

enough. The analysis shows that a minimum ski width of .63 meters or 2’ 3/4" is necessary for

the Jet Blade to work properly. With this design the Jet Blade will be able to get up and on plane

with the given design and available power. From the graph it can be seen that at very low

speeds the angle that is required for the Jet Blade to get on plane is approximately 20o. Figure

16 provides a model of Jet Blade at 20o to the horizontal plane. This image was compared Figure

17 which is a photo of the Wet Bike during its planing process and the images.

Figure 16: Jet Blade During Planing Process Figure 17: WetBike During Planing Process

Interestingly, these images show that the designed angle of attack is very similar to the actual

angle of attack that was demonstrated. This again reinforces the feasibility of the design. The

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design of the front skis was not incorporated into the planing process. This was done to simplify

the modeling as well as to insure the design of the rear ski was robust enough to provide

sufficient lift for the entire Jet Blade. The addition of the front ski’s and the hull will only add to

the lift force that is generate and will help to get the Jet Blade onto plane even faster.

5.3.3 Suspension and Steering

A model of the Suspension and Steering can be viewed in Figure 18.

Figure 18: Active Tilt Suspension

The Active Tilt suspension system allows the Jet Blade to tilt as it travels through a corner. As

seen by Figures 19-21, the suspension system is shown in a right turn, straight and left turn

positions respectively.

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Figure 19: Active Tilt - Right Turn

Figure 20: Active Tilt – Straight

Figure 21: Active Tilt - Left Turn

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This suspension design is made from aluminum with every rotating axis being connected with

shoulder bolt connections. This will provide the degrees of freedom necessary for the active tilt

suspension system to function properly. It is necessary that the tilting motion be uniform and

smooth. Another feature of the Active Tilt Suspension system that will aid in rider comfort is the

pneumatic shock absorbers that are integrated into the double wishbone suspension design as

seen in Figure 22: Compressed Suspension. When the suspension is fully compressed it provides

Jet Blade with 8" of travel of the front skis. This will allow for comfortable traverse over rough

water.

Figure 22: Compressed Suspension

To verify the feasibility of this design, several major components were analyzed using FEA.

Figures showing force loading, resultant stress, and displacement can be found in Appendix C.

In each case, maximum experienced stress was well below the material yield stress of 40 ksi.

Position and torque calculations were done in order to prove the feasibility of the designs, these

calculations can be viewed in Appendix B. In order to determine the position of the handle bars

at full suspension tilt a set of kinematic position equations was derived, from this it was able to

be determined that a miter gear set and a spur and pinion gear set could be used. This also

determined that a 1:1 gear ratio for both gear sets was the optimal gear ratio. This provided a

1:1 overall ratio between the turning of the handle bars and the tilting of the Jet Blade. While

this was optimal for the tilting aspect of the design, it raised some issues with the amount of

force required to right the craft after a turn. Different options are being explored such as spring

assisted tilt correction and revision of mathematical models to ensure proper moment

balancing. This is being done in order to reduce the amount of torque that is required by the

operator during turning. It is important that the steering of the Jet Blade be light and responsive

so as to reduce rider fatigue and maintain a pleasurable riding experience.

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5.3.4 Propulsion

As shown in Figures 6 and 7, the propulsion system to be used in the Jet Blade is a bottom intake

jet pump. The bottom intake and integrated right angle gearbox allow for maintained

performance and proper motor and pump configuration. Shown in Figure 7, the motor to be

used in the Jet Blade is a two stroke, water-cooled, Suzuki that produces 50 HP. This motor is

ideal because of its compact integration with the jet pump. Figure 15: Results of Savitsky

Procedures indicates that 50 HP will be ample power to achieve planing.

5.3.5 Complete Design

Figure 23: Complete CAD Model

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Figure 24: Complete Model – Front View

Figure 25: Complete Model – Right Turn

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Figure 26: Complete Model – Left Turn

6 Testing

6.1 Safety

The most important safety aspects to test are hull buoyancy and the ability to seal out

water. These tests will be performed in water just deep enough to test floatation. The Jet

Blades ability to right itself in the water will also be tested. In addition, the control systems will

be thoroughly tested to verify that the rider can maintain control at all times and that the

engine will be killed in the case of a crash. Marine grade foam will also be implemented in the

case of water breaching the hull in order to ensure that the watercraft will not sink.

6.2 Launch Capabilities In order to test the launch capabilities of the Jet Blade a timed test will be performed. The Jet

Blade will be loaded on a trailer. The trailer will then be backed down to the water and the Jet

Blade will begin to be unloaded. The process of unloading the Jet Blade should take no longer

than five minutes and should be able to be done with one person.

The unloading and loading of the Jet Blade will be very similar to that of a boat or a conventional

personal watercraft. The Jet Blade and trailer will be backed down into the water until the Jet

Blade floats off of the trailer. At this point the Jet Blade will be floated off of the trailer and tied

33

to the dock. The trailer will then be removed from the water and the rider will return to the Jet

Blade still tied to the dock. The loading process will function the same way, but in reverse

order.

6.3 Strength In order to test the strength of the Jet Blade it will be jumped off of a standard boat wake. This

process, although crude, will demonstrate the strong rigid construction of the hull, suspension

and skis. The Jet Blade should be able to withstand fifteen repeated jumps of a two foot tall

wave (largest amplitude wave in standard operating conditions).

6.4 Performance and Handling The goal of the Jet Blade is to provide an unparalleled riding experience on the water. While this

is very difficult to quantify, there are test that can be done in order to measure the Jet Blade to

standard personal watercraft. In this test the Jet Blade will be compared to a Kawasaki STX 1100

(Seated PWC), a Kawasaki JS550 (Stand up jet ski) and a Kawasaki Sport Cruiser JL650 (Seated

Side by Side PWC). All four of these personal watercrafts will be evaluated on the same tests.

The first test that will be performed is a maneuverability test. This test will incorporate a slalom

style course that is arranged on a local inland lake. Each water craft will go through the course

as fast as possible. The time it takes for each craft to complete the course will be timed as well

as the level of difficulty the rider faced in completing the course on a 1 to 10 scale. With 10

being the most difficult to maneuver and 1 being the easiest.

The second test that will be performed is acceleration. All watercrafts will start from a stop and

race a distance of 100'. The time it takes for each craft to complete the course will be recorded

and compared. All of the PWC's are equally powered except for the Kawasaki STX 1100 which

will be excluded from this test.

The rider experience of each watercraft will be the third and final test. In order to do this a

group of unbiased riders will be selected and each rider will ride each PWC for 5 minutes. At the

end of each ride the rider will be asked to rate the experience of that watercraft in the following

categories: ease of use, excitement, comfort, skill required, and potential for improvement.

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7 Business Plan

7.1 Market Competition Currently there is nothing on the market that is identical to Jet Blade. Jet Blade is a unique

product with a target market comprised of individuals that have some discretionary income, as

it is a luxury item. Specifically individuals or those individual’s kids that have an interest in

extreme sport and have access to a body of water to ride Jet Blade. The key marketing strategy

for Jet Blade is to create superior customer value by means of differentiation. Competitors to Jet

Blade would include any manufacturer of personal watercraft vehicles. Expected major

competitors may be seen below in Table 3.

Table 3: Market Competition

Personal Water Craft Base Price

Sea-Doo Spark $ 4,999.00

Yamaha Superjet 2015 $ 8,499.00

Kawasaki Jet Ski STX-15F $ 9,699.00

Yamaha FX Cruiser SVHO $ 15,499.00

Quadski $ 40,000.00

7.2 Break-Even Analysis In order to perform a break-even analysis variable and fixed costs were researched and

estimated. These costs may be seen below in Table 4. With a selling price of $12,000.00 a break-

even point of 75 units was calculated.

Table 4: Estimated Production Costs

Production Cost Component

Per Unit Total Annual

Raw Materials $ 2,375.00 $ 296,875.00 Direct Labor $ 2,500.00 $ 312,500.00 Variable Overhead $ 400.00 $ 50,000.00 Total Variable Manufacturing Cost

$ 5,275.00 $ 659,375.00

Annual Rent 15,000 @ $3.50/sq·ft * $ 52,500.00 Utilities 15,000 @ $2.30/sq·ft * $ 34,500.00 Insurance $ 100,000.00 Selling and Administration

$ 30,000.00

Marketing $ 20,000.00 Engineering $ 200,000.00 Total Fixed Expenses $ 437,000.00

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Total Expenses $ 1,096,375.00 Selling Price $ 12,000.00 $ 1,500,000.00 Profit (Loss) $ 403,625.00 *http://www.cityfeet.com/cont/mi/grand-rapids-industrial-space#pgNum=6 *http://www.buildings.com/article-details/articleid/16749/title/utility-expenses-decrease- across-u-s.aspx

8 Conclusion

After the preliminary design decisions, calculations, and budgeting Team 6 has decided that the

project is feasible. The Team is willing to undertake the task of manufacturing a completely

functional Jet Blade prototype.

9 Acknowledgements

The team would like to acknowledge the following people for their support and advice on the

project.

Ned Nielsen - Team advisor and Mechanical Engineering Professor

Phil Jasperse - Metal shop instructor

Ren Tubergen - Mechanical Engineering Professor

10 Bibliography [1] Nelson, Tyler. Jet Powered Watercraft. Still Water Properties, assignee. Patent 3948206. 6

Apr. 1976. Print.

[2] Savitsky, Daniel : "Hydrodynamic design of planing hulls", Marine Technology, Vol. 1, No.1,

1964.

[3] http://www.calvin.edu/academic/engineering/2012-13-team15/ [4] http://thekneeslider.com/tilting-v-max-trike-by-tilting-motor-works/

[5] http://illustrations.marin.ntnu.no/hydrodynamics/resistance/planing/index.html

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Appendix A: Project Gantt Chart

37

38

Appendix B: EES Calculations EES Buoyancy Calculations (Picture : buoyancy_calcs_ees )

39

EES Gear and Torque Calculations

40

41

Appendix C: FEA Analysis

Figure 27: A-Arm Force Loading

Figure 28: A-Arm Stress Results

Figure 29: A-Arm Displacement Results

42

Figure 30: Yoke Force Loading

Figure 31: Yoke Stress Results

Figure 32: Yoke Displacement Results

43

Figure 33: T Force Loading

Figure 34: T Stress Results

Figure 35: T Displacement Results