2014 Team 14: Expedition Camper Engineering 340: Senior Design Project Calvin College DESIGN REPORT INFORMATION TECHNOLOGY 1 © 2014, Team 14 and Calvin College This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 2 Executive Summary This report details the research and design of the Expedition Camper. The team designed this camper to be taken off-road over very rugged terrain. The most unique aspect of this project was that the camper was designed to also function as a boat. The camper’s complex design and robust construction allow it to be pulled over large obstacles encountered on off-road trails, as well as to be removed from the trailer and placed into a pond or lake so that it can traverse across water. Team Expedition Camper, otherwise known as Team 14, chose this project for their senior capstone project. Completion of this report is also accompanied by a working prototype, tested for off-road travel and functionality as a boat and camper. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 3 Contents Executive Summary ................................................................................................................................ 2 Table of Tables........................................................................................................................................ 6 Table of Figures ...................................................................................................................................... 7 1 Introduction ........................................................................................................................................ 9 1.1 The Project............................................................................................................................... 9 1.2 Design Norms .......................................................................................................................... 9 1.2.1 Transparency .................................................................................................................... 9 1.2.2 Integrity ........................................................................................................................... 9 1.2.3 Trust................................................................................................................................. 9 1.3 The Class ................................................................................................................................. 9 2 Project Management ......................................................................................................................... 10 2.1 The Team ............................................................................................................................... 10 2.1.1 2.2 Schedule ................................................................................................................................ 11 2.2.1 Task List ........................................................................................................................ 11 2.2.2 Gantt Chart ..................................................................................................................... 12 2.3 3 Team Roles .................................................................................................................... 10 Finance .................................................................................................................................. 13 Project Breakdown ........................................................................................................................ 13 3.1 Project Description ................................................................................................................. 13 3.1.1 Camper........................................................................................................................... 13 3.1.2 Trailer ............................................................................................................................ 14 3.2 Objectives .................................................................................................................................... 14 3.2.1 Dual Capability ..................................................................................................................... 14 3.2.2 Lightweight ........................................................................................................................... 14 3.2.3 Durable ................................................................................................................................. 14 3.2.4 Maneuverable ....................................................................................................................... 14 3.2.5 User Friendly ........................................................................................................................ 15 3.2.6 Aesthetically Pleasing ........................................................................................................... 15 4 Project Specifications ....................................................................................................................... 15 4.1 Camper .................................................................................................................................. 15 4.1.1 Size ................................................................................................................................ 15 4.1.2 Shape ............................................................................................................................. 16 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 4 4.1.3 Weight ........................................................................................................................... 16 4.1.4 Durability ....................................................................................................................... 17 4.1.5 Materials ........................................................................................................................ 17 4.1.6 Aesthetics ....................................................................................................................... 19 4.1.7 Usability......................................................................................................................... 19 4.2 Trailer .................................................................................................................................... 19 4.2.1 Materials ........................................................................................................................ 20 4.2.2 Maneuverability ............................................................................................................. 20 4.2.3 Height Variation ............................................................................................................. 20 5 Design Process ................................................................................................................................. 20 5.1 Camper .................................................................................................................................. 20 5.1.1 Stability .......................................................................................................................... 20 5.1.2 Launch Parameters ......................................................................................................... 24 5.1.3 Boat Frame ..................................................................................................................... 27 5.1.4 Front Wall Section.......................................................................................................... 30 5.1.5 Soft Top and Mount........................................................................................................ 31 5.1.6 Motor and Motor Mount ................................................................................................. 33 5.2 Trailer .................................................................................................................................... 35 5.2.1 Trailer Frame.................................................................................................................. 35 5.2.2 Hitch .............................................................................................................................. 36 5.2.3 Suspension ..................................................................................................................... 38 5.2.4 Tie Down Points ............................................................................................................. 42 5.2.5 Straps ............................................................................................................................. 42 5.2.6 Trailer Jacks ................................................................................................................... 43 5.3 Finite Element Analysis ......................................................................................................... 43 5.3.1 Camper/Boat FEA .......................................................................................................... 44 5.3.2 Trailer FEA .................................................................................................................... 46 6 Testing ............................................................................................................................................. 49 6.1 Safety..................................................................................................................................... 49 6.2 Initial Testing ......................................................................................................................... 50 6.2.1 Drop Testing .................................................................................................................. 50 6.2.2 Launch Testing ............................................................................................................... 50 6.2.3 Stability Testing ............................................................................................................. 50 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 5 6.3 Modifications ......................................................................................................................... 50 7 Business Plan ................................................................................................................................... 50 7.1 Market Competition ............................................................................................................... 50 7.2 Break-even Analysis .............................................................................................................. 51 8 Conclusion ....................................................................................................................................... 52 9 Acknowledgements .......................................................................................................................... 54 10 Bibliography ................................................................................................................................... 55 Appendix A: EES Calculations ............................................................................................................. 56 Appendix B: Design Drawings ............................................................................................................. 58 Appendix C: Budget .............................................................................................................................. 64 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 6 Table of Tables Table 1: Anticipated tasks for design and build of the Expedition Camper. ............................................ 11 Table 2: Cost estimate. .......................................................................................................................... 13 Table 3: Market research for the Expedition Camper.............................................................................. 16 Table 4: Tow capacities of typical off-road vehicles. .............................................................................. 17 Table 5: Properties of common boat hull materials. ............................................................................... 18 Table 6: Component weights. ................................................................................................................ 21 Table 7: Weight calculations.................................................................................................................. 24 Table 8: Off-road campers and their base purchase prices. ..................................................................... 51 Table 9: Cost per camper and annual fixed costs. ................................................................................... 51 Table 10: Break Even Analysis for Expedition Camper. ......................................................................... 52 Table 11: Complete Project Budget ....................................................................................................... 64 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 7 Table of Figures Figure 1: The team – Mitch Hopkins, Jordan Veltema, Nathan Hiemstra, Jordan Mast. .......................... 10 Figure 2: Gantt chart showing an anticipated schedule for the team. ....................................................... 12 Figure 3: Angle of list as a function of the bottom width of the boat. ...................................................... 22 Figure 4: Distance boat lists into the water as a function of width of the boat. ........................................ 23 Figure 5: Distance Camper will sink into water based on weight. ........................................................... 25 Figure 6: Camper height dimensions for launch parameter reference. .................................................... 26 Figure 7: Dimensions and calculations to find height difference between points A and B. ...................... 27 Figure 8: Approximate dimensions for Jeep-styled tub portion of camper............................................... 28 Figure 9: Approximate boat hull dimensions. ......................................................................................... 29 Figure 10: Frame of the camper. ............................................................................................................ 30 Figure 11: Front wall in camper frame. .................................................................................................. 31 Figure 12: Approximate top dimensions. ............................................................................................... 32 Figure 13: Approximate roll bar dimensions. ......................................................................................... 33 Figure 14: Motor mount on back of camper frame ................................................................................. 35 Figure 15: 501 with a 510 off-road trailer hitch by Lock N’ Roll ............................................................ 36 Figure 16: Solid works model of three axis hitch.................................................................................... 37 Figure 17: Leaf spring suspension system. ............................................................................................. 38 Figure 19: Stress on leaf spring as a function of drop height. .................................................................. 39 Figure 20: Air bag suspension system. ................................................................................................... 40 Figure 21: Arm for air bag suspension. .................................................................................................. 41 Figure 22: Stacker jacks and scissors jacks. ........................................................................................... 43 Figure 23: Boat stress FEA. ................................................................................................................... 44 Figure 24: Boat deflection FEA. ............................................................................................................ 45 Figure 25: Final camper/boat FEA model. ............................................................................................. 46 Figure 26: Trailer stress FEA. ................................................................................................................ 47 Figure 27: Trailer displacement FEA. .................................................................................................... 47 Figure 28: Airbag mounting bracket FEA simulation. ............................................................................ 48 Figure 29: Stress FEA of final trailer design. ......................................................................................... 49 Figure 30: Preliminary design drawing. .................................................................................................. 58 Figure 31: Side view, top down. ............................................................................................................. 59 Figure 32: Side view, top up ................................................................................................................... 59 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 8 Figure 33: Front View ............................................................................................................................ 60 Figure 34: Top View ............................................................................................................................... 60 Figure 35: Boat removed from trailer..................................................................................................... 61 Figure 36: Colored side view, top down. ................................................................................................ 62 Figure 37: Colored side view, top up. ..................................................................................................... 62 Figure 38: Colored perspective view showing entrance.......................................................................... 63 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 9 1 Introduction 1.1 The Project Team 14, Expedition Camper, set out to design and build a recreational unit that functions as a camper and a boat. The design allows for the camper to be removed from the trailer, placed into the water, and driven away as a boat. The product was aimed at outdoor, wilderness enthusiasts who enjoy the beaten trail rather than the paved road. The camper is lightweight and durable, allowing it to travel on rugged terrain. The camper is sleek, aesthetically pleasing, and aerodynamic. The camper is also easily detachable from the trailer and has the ability to move through water. Optimization calculations were used to determine the best combination of all engineering aspects. 1.2 Design Norms As Calvin engineers in training, our team strove to uphold Christian values in the design of the camper. In order to uphold these Christian values, the following design norms were implemented. 1.2.1 Transparency In order for the Expedition Camper to appeal to the greatest number of people, it was designed so that the customer would be able to learn how to use it rather easily. The team ensured that the design of the Expedition Camper was not only user friendly, but also that it held in high regard the safety and well-being of the end user. 1.2.2 Integrity In order for the Expedition Camper to fulfill the design norm of integrity, it was designed to be intuitive and easy to operate. The design was simple enough for the common user to understand how it works. 1.2.3 Trust The Expedition Camper itself was a good concept, but in order to meet the design norm of trust, it also had to endure sustained use. The Expedition Camper is designed to be strong and reliable, ensuring that the user will feel completely safe when using the product. 1.3 The Class This project spanned the entire two semesters of the team’s senior year in Calvin College’s engineering program. The senior capstone project class challenged the students in the program to use all the knowledge they had gained to tackle a real-world project. With the knowledge and experience the team had gained over their years of coursework, the team created something unique and fun. Using gained knowledge, the team performed detailed studies and calculations to determine the best way to design and build the product. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 10 By the end of the class, the team was able to build a product that they showcased on senior design night. The team’s ability to solve complex problems was well represented by the end product. 2 Project Management 2.1 The Team Team Expedition Camper consisted of Nathan Hiemstra, Mitchell Hopkins, Jordan Mast, and Jordan Veltema. Each member studied in the mechanical concentration of engineering at Calvin College. Jordan Veltema’s background in manufacturing, as well as experience with automotive body repair, proved to be helpful during the project. Both Jordan Mast and Nathan Hiemstra worked at Innotec and were able to use their experience with manufacturing equipment and machine design. Mitchell Hopkins’ experience with the use of design software, through his work at Progressive Surface, also made it easier to create design drawings. The team members are shown in Figure 1. Figure 1: The team – Mitch Hopkins, Jordan Veltema, Nathan Hiemstra, Jordan Mast. 2.1.1 Team Roles Nathan Hiemstra – Design and Manufacturing This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 11 Nathan had a large amount of knowledge with regard to manufacturing, as well as skills in sheet metal work, welding, and fabrication of various metal products. Nathan also has vast knowledge with regard to off-road vehicles. He was in charge of managing the construction of the prototype and worked closely with Mitchell to develop a proper prototype design that allowed for ease of manufacturing. This also included allocating people and resources to find all of the necessary parts, perform fabrication, and develop subassemblies to build the prototype. Jordan Mast – Website Design/ Team Management Jordan has the most knowledge with respect to website design and team management, as well as a strong knowledge of metal fabrication. He was in charge of creating and keeping the website up to date, as well as being heavily involved with the manufacturing of the prototype. Furthermore, Jordan was tasked with managing the team ensuring that they stay on schedule and within budget. Jordan Veltema – Documentation and Manufacturing Jordan had excellent editing and documentation skills, as well as an expansive knowledge about cars and other vehicles. He was in charge of making the final edits on all written documents done collectively by the team, and also is assisted in the design and building of the prototype. Mitchell Hopkins – Design and Analysis Mitchell has a vast knowledge of computer software design. His extensive experience with the SolidWorks software package allowed him to construct a detailed 3D model of the prototype. He was in charge of creating a complete model of the project as well as performing Finite Element Analysis of various parts or subassemblies. He worked closely with the entire team in order to ensure that manufacturing of all nonpurchased parts went smoothly. 2.2 Schedule 2.2.1 Task List The following table shows the task list for the year of what was to be completed for the project. In order to finish the project, every item on the task chart had to be addressed in some way or manner. Many of these tasks are addressed in more detail in later sections of the report. Table 1: Anticipated tasks for design and build of the Expedition Camper. TASK NAME DESCRIPTION PROJECT MANAGEMENT Determine goals and estimate time for each task. GANTT CHART Schedule of events and tasks for the year. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 12 RESEARCH Research necessary for all aspects of the design. BUDGETING Budgeting to determine the cost of the project. BUDGET PROPOSAL Finalize total budget. CONCEPTUAL DRAWINGS Preliminary drawings of end product. DESIGN Designing each component to meet engineering requirements. FEA ANALYSIS Perform computer simulations to test component strengths. PPFS REPORT Mid-year report stating the feasibility of the project. MANUFACTURING Final stages consist of the construction of the project. TESTING Testing will be done on the product. FINAL REPORT A final report will be issued on the website. 2.2.2 Gantt Chart At the beginning of the year, the team put together a list of anticipated tasks that would need to be completed. The task list is shown previously, in Table 1, and a Gantt Chart is shown below, in Figure 2, indicating an approximation of how each task fits within the schedule of the year. Figure 2: Gantt chart showing an anticipated schedule for the team. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 13 2.3 Finance The following spreadsheet, Table 2, provides an estimation of project expenses required for building a prototype of the Expedition Camper. This table shows an estimation of the team’s budget. However, over the course of the project the team realized that they had underestimated the project cost. The final cost of the project ended up being more than expected and a complete bill of materials with associated costs can be found in Appendix E. Table 2: Cost estimate. STARTING BALANCE $ 2,255.00 COMPONENTS Cost Remaining Balance TRAILER & BOAT $ 800.00 $ 1,455.00 TROLLING MOTOR $ 250.00 $ 1,205.00 WOOD $ 100.00 $ 1,105.00 ALUMINUM $ 425.00 $ 680.00 STEEL $ 200.00 $ 480.00 ELECTRICAL $ 75.00 $ 405.00 AIR BAG SUSPENSION $ 100.00 $ 305.00 MISC $ 100.00 $ 205.00 CONTINGENCY 10% RAW MATERIALS ADDITIONAL 3 Project Breakdown 3.1 Project Description The project was broken down into two main categories, the camper and the trailer. The camper section discusses the aspects of the unit being used as a camper and a boat. The trailer section focuses on the structural aspects of the trailer and on equipping it to be towed off-road. 3.1.1 Camper The Expedition Camper was designed for one or two people. When it is being used on land as a camper, it is attached to the trailer with tie-downs to ensure safety of the user while moving in and out of the camper. The camper also provides enough room for proper sleeping accommodations in various types of weather. When the soft-top is up, the interior of the camper is completely sealed from the outside keeping the bugs and rain out. The clever design of the soft top and soft top mount allows the user to easily assemble for shelter and disassemble for use on the water. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 14 The camper is also able to operate safely as a watercraft. The launch and retrieval of the Expedition Camper is simple enough for one person to do on their own. The outboard motor is attached to a mount on the back of the camper. When the camper is out on the water, it is stable enough for a person to move around without struggling to stay balanced. The user can maneuver the Expedition Camper across the water with ease. Operating the throttle and steering the motor is comfortable and straightforward. 3.1.2 Trailer The trailer is designed and built to withstand any conditions that it will be required to face. The air bag suspension allows for a 9.7 inch range of lift. This offers a way for the trailer to sit high when being towed and lowered when launching the camper into the water. The trailer will undoubtedly experience a variety of uneven pathways, but the multi-axial hitch greatly reduces the stresses in the hitch connection. The trailer is built to be towed across any type of terrain that a Jeep or other off-road vehicle can travel across. The trailer is also able to withstand weathering and impact from rocks and other rough terrain. 3.2 Objectives 3.2.1 Dual Capability The main objective for this project was to design the camper to be capable of functioning as a camper and a boat. Requirements for the camper aspect were that it could be used for sleeping accommodations and could store various camping supplies. Requirements for the boat aspect were that it could be safely used to travel on water. 3.2.2 Lightweight An objective was set for the unit to be no more than 1500 pounds dry weight. This 1500 pounds comprises the camper and the trailer. This objective was developed because the camper should be easy to tow off-road by typical off-road vehicles, many of which do not have a very high towing capacity. Furthermore, by designing the camper to be lightweight, it would be easier to launch and retrieve. 3.2.3 Durable For the unit to be towed in off-road situations, it must be durable. An objective set for the durability of the camper was that it must be able to survive a drop of up to 1 foot. A sudden drop of 1 foot would have large impact stresses on the camper, and it must be durable enough to withstand these stresses. 3.2.4 Maneuverable One requirement of the camper being used as a boat was that it must be able to travel through the water with ease. This refers to a few different aspects such as how fast it can go, how easily it can be turned, and how stable it is when traveling. A goal of a minimum of 5 mph was set for the speed. This objective was This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 15 set because it was desired for the camper to be able to function as a boat, therefore, it must be able to compete with other small boats in the areas of speed and stability. 3.2.5 User Friendly For the camper to be used successfully, it must be user friendly. This applies to a variety of areas of the camper both onshore and offshore. One aspect was that it must be easy to launch and retrieve the camper. Furthermore, it must be easy to raise and lower the soft-top. On the water, the camper must be easy to use for activities such as fishing and duck hunting. 3.2.6 Aesthetically Pleasing A general objective for the camper was that it would be aesthetically pleasing. The team wanted to design a camper that looks mostly like a camper, with the additional functionality of a boat. It was a goal for the team to build a camper that looks well done and that draws the attention of people passing by. 4 Project Specifications In designing an Expedition Camper, there were numerous factors that needed to be taken into account. Because the Expedition Camper has the ability to function as both a camper and a boat, discussion of the multifunctional aspects of the Expedition Camper were divided into two sections: those associated with the camper portion and those associated with the trailer portion. 4.1 Camper For the camper portion of the design, defined to be the bottom tub and the soft-top, important design factors included size, shape, weight, materials, durability, aesthetics, and usability. 4.1.1 Size The first factor researched was size. There were many different dimensions that were important in the design of the Expedition Camper. The first group of dimensions that were determined describe the usable space inside the camper. In order to determine acceptable interior camper dimensions, research was performed with regard to different off-road campers currently on the market. Table 3 summarizes these interior dimensions for three of the major off-road campers. From these benchmark examples, it was determined that the interior of the camper should have a width of approximately 5 feet, a length of approximately 8 feet, and a height of approximately 4 feet. Given these rough dimensions, several other factors were used to determine more exact interior dimensions. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 16 4.1.2 Shape Another important factor of the boat portion for the camper was the shape of the hull. While there were a variety of boat hull shapes that could be used, such as pontoons, v-hull, or tri-hull, it was clear that a slight V-shaped bottom best suites the functionality of the Expedition Camper. Unlike other boat bottom shapes, the slight V-bottom provides a low profile. This was important for ground clearance when traversing over rough, rocky, and uneven terrains. It was also important from an aesthetics point of view because it was desired that the Expedition Camper be disguised as more of a camper than as a boat. Furthermore, a slight V-bottom shape allowed for the Expedition Camper boat portion to be launched in more shallow waters than any other hull shape would offer. This was an important aspect, which will be described more in later sections, given that the camper would need to have the ability to launch without access to a ramp made specifically for launching a boat. 4.1.3 Weight Another important factor evaluated was the dry weight of the camper. The dry weight was defined to be the weight of the camper without the weight that would be added from additional items such as water jugs, gasoline cans, furnishings, baggage, tools, equipment, and so on. Research of the dry weights of other offroad campers currently on the market was again used in the determination of an acceptable dry weight for the Expedition Camper being designed. These dry weights are included in Table 3 for the same three offroad campers used for dimension criteria. From these weights it was concluded that the camper should have a dry weight of 1500 pounds, which is on the higher end of the examples provided. This was because it was assumed that the additional boat functionality, not present in the benchmark examples, adds some extra weight to the camper. Table 3: Market research for the Expedition Camper. TRAILER MOBY1 XTR 1 SO-CAL TEARDROPS LENGTH WIDTH HEIGHT DRY WEIGHT [IN] [IN] [IN] [LBS.] 80 54 or 60 45 1,500 109.5 53 44.5 1,250 107 54 45 1,283 THE KRAWLER2 ADVENTURE TRAILERS TEARDROP 3 1 http://moby1trailers.com/moby1-xtr/ http://www.socalteardrops.com/page.php?p=22 3 http://www.adventuretrailers.com/teardrop.html 2 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 17 Furthermore, the dry and overall weight of the camper become important aspects when evaluated according to the measure of the tow capacity of the typical off-road vehicle. Table 4 contains research with regard to the tow capacity of several typical off-road vehicles. This research confirmed the maximum dry weight decision of 1500 pounds and also set a requirement that the weight of the camper should not exceed 2000 pounds when fully loaded with all accessories. Table 4: Tow capacities of typical off-road vehicles. VEHICLE TOW CAPACITY [LBS.] JEEP WRANGLER (2 DOOR, 4 DOOR)4 TOYOTA FJ CRUISER NISSAN FRONTIER 6 5 2,000 - 3,500 4,700 6,500 4.1.4 Durability One of the key purposes for the design of the camper was that it should have great durability. The camper and top are able to withstand the impact forces and heavy vibrations encountered during use in the harshest of off-road environments. In order to achieve a design featuring a high level of durability, material properties, in addition to overall structural design, were extremely important. Given that the boat portion of the Expedition Camper was in the most susceptible position to be affected by the harsh environments experienced in an off-road setting, material considerations are discussed in the following section of the report. 4.1.5 Materials Correct material selection was pivotally important due to the fact that the Expedition Camper was purposed to be subjected to some of the harshest environmental conditions when put to use and must also meet the weight limits the team set. Research revealed four potential candidates for material selection: wood, fiberglass, aluminum, and steel for the framework of the camper. Additionally a removable material for the roof was needed to make the camper more functional as a boat when in water. 4 http://www.jeep.com/en/2013/wrangler/capability/towing/ http://www.toyota.com/fjcruiser/features.html#!/exterior/4702/4703/4704 6 http://www.nissanusa.com/trucks/frontier 5 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 18 In order for the end product to comply with the other design requirements, wood was quickly eliminated. This was because the boat portion of the camper must be capable of withstanding harsh conditions of the off-road environment, such as impact loads, abrasive contact, and constant vibrations. Not only would a wooden hull be impractical for withstanding impacts and abrasion, it also would be susceptible to rattle apart and therefore would develop leaks over time. Furthermore, development of a wood hull that can withstand the conditions seen in an off-road environment would undoubtedly lead to a design that does not fit within the weight constraints of the project. An evaluation of the three remaining materials, fiberglass, aluminum, and steel, revealed that aluminum was the optimal construction material for the hull of the camper. An aluminum hull best fit the requirements of the project and was chosen for several different aspects. These include strength, weight, abrasive resistance, and cost. From a strength point of view, low carbon steel had the highest tensile strength, as shown in Table 5. However, because a design criterion of the project was that it must be relatively lightweight, building the camper hull from an extremely dense material, such as steel, most assuredly would have led to an Expedition Camper that surpassed weight constraints. On the opposite end of the spectrum, fiberglass has a relatively weak tensile strength. While a fiberglass hull could provide enough strength, the amount of fiberglass needed to build the hull would result in an Expedition Camper that was heavier than desired. The main interest from a design standpoint was the strength-to-weight ratio of the material. Because 5052 aluminum stands between fiberglass and steel with both tensile strength and density, it boasts the highest strength-to-weight ratio. Therefore, aluminum was the best candidate for construction material from both a strength and weight point of view. Table 5: Properties of common boat hull materials. 7 MATERIAL TENSILE STRENGTH DENSITY [LBS./FT3] STRENGTH/WEIGHT [PSI] RATIO FIBERGLASS 18,000 95-100 180-189 LOW CARBON STEEL 58,000-68,000 470 123-145 5052 ALUMINUM 33,000 167 197 Not only did aluminum score high in the strength and weight categories, it also had several other favorable properties with regard to abrasive resistance and weather-ability. Unlike fiberglass, it does not gouge or scratch easily. These material properties were extremely desirable for the Expedition Camper, given that it 7 http://www.trekkeryachts.com/construction.php This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 19 would see the occasional brush of a tree branch or impact of a stone. Additionally, aluminum ranks high in the category of weather-ability. Both steel and fiberglass are highly susceptible to deteriorate over time. Steel corrodes quickly with the elements, while fiberglass blisters and delaminates. On the other hand, the only concerns with aluminum were that it can develop cracks if cyclically loaded and not reinforced properly and that it could develop corrosion when in contact with dissimilar metals. However, both of these are easily remedied with care. It is true that fiberglass boats are less expensive to produce in a long-run production environment. Once the molds have been built for the boat, an easy, repeatable process could be used to mold multiple boat hulls. However, the capital investment costs required for good, production quality molds are staggering. With aluminum, there were no hefty up-front costs like this required. Along with the aluminum framework a soft top was needed in order to enclose the camper. The team determined that using a Jeep soft top would serve this purpose and be easily integrated with the design. 4.1.6 Aesthetics The overall look and feel of the camper also played an influential role in the design. In order for the Expedition Camper to be a competitive option for outdoor enthusiasts, the design needed to be aesthetically pleasing. One of the largest groups of people for whom the Expedition Camper would appeal, would be Jeep owners due to the Jeep’s extreme level of popularity in the off-road realm. Because of this fact, it was decided that the Expedition Camper would do well to incorporate Jeep styling. Furthermore, with regard to marketability, there was no Jeep-styled multipurpose off-road camper currently on the market. The absence of similar products on the market provided a good opportunity for the Expedition Camper. 4.1.7 Usability Another critical factor of the project, specifically with respect to the camper portion, was the ease of use. This was especially true in its application with regard to the top of the camper. This was a crucial requirement especially when the Expedition Camper was used in its boat function. The sides and roof of the top are easily removable so they do not obscure the view of users when the camper is used in its boat function. To achieve this transformable functionality, the sides and top of the camper were constructed from a vinyl/cloth material so that they could be easily zipped out, rolled up, or folded down. This also allows users to stand up inside when the Expedition Camper is being used as a boat. 4.2 Trailer For the trailer portion of the design, important design factors included materials, maneuverability, and height variation. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 20 4.2.1 Materials The selection for materials of the trailer were based on similar criteria as the camper portion. The main objective was that this trailer would take a lot of beating while being used off-road. In order to ensure the trailer would handle high stresses during travel, 2 inch x 4 inch x 1/8 inch thick steel tubing was used for the frame of the trailer and 2 inch x 3 inch x 1/8 inch thick steel tubing was used for the cross beams supporting the camper portion. FEA models were used, and are explained in more detail later, to determine if this material would be strong enough. In order to attach the suspension system to the frame ¼ inch thick steel mounting plates were welded to the trailer. These give the air bags a flat and strong surface to push against. Along with the suspension mounts, brackets were made out of the same material for the shocks. The shocks keep the trailer from bouncing around excessively. Along with the ruggedness of the frame the team decided to include UHMW strips on the cross-support beams to protect the bottom of the boat, as well as to allow it to be more easily removable. The friction coefficient of UHMW is much lower than that of steel which is why sliding the boat on these strips makes it easier to move on and off the trailer. 4.2.2 Maneuverability Maneuverability was one other key aspect the team wanted to address. Because the Expedition Camper was made for off-roading, maneuverability was key. Two key ways the team addressed this issue was through a multi-axial hitch as well as an air bag suspension, which were covered in more detail in the proceeding section. The multi-axial hitch allows for the trailer to move more independently from the vehicle towing it. Because off-road terrain is so uneven, this was a great benefit to have while towing the Expedition Camper. 4.2.3 Height Variation One of the more luxurious additions to the trailer was the use of an air bag suspension system, because the camper would be launched in areas without a boat launch as well as travel over larger obstacles. The Airlift Dominator D2600 air bags give an overall height variation of up to 9.7 inches. This addition gives the trailer the ability to pass over large rocks as well as provide adjustability to sit low during the launch process. 5 Design Process 5.1 Camper The team went through several different modifications throughout the design process of the camper. 5.1.1 Stability One major hurdle in the design of the boat portion of the Expedition Camper was its stability on water. Typically, small aluminum boats are known for being quite unstable on water. For example, small This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 21 aluminum boat users are often forced to stay close to the centerline of their boats due to the fact that movement to the outer edge of the boat causes larges angles of list, or tipping into the water. In fact, these boats can become so unstable on water that movement of large masses, such as humans, to the outer edges of the boat can cause the boat to capsize, therefore, one area requiring extensive research and calculations was stability. Research showed that a slight V-bottom boat was not only the best option from an off-road ground clearance and ease of launch standpoint but also because of its increased stability on water. There are several factors that play a significant role in determining the stability of a V-bottom aluminum boat. The most significant factors include the location of the center of gravity of the boat, as well the width of the bottom of the boat. After performing detailed research on other off-road campers currently on the market, it was determined that the typical width of off-road campers are approximately 5 feet. Therefore, it was assumed that the bottom of the boat hull portion of the camper should have a width that was close to the standard 5 foot width. In order to determine the relationship between boat stability and width, engineering relationships used in naval architecture were required. Detailed research of these relationships revealed that the models which are used are very complex. Therefore, since complex models for stability calculations were difficult to implement, by extensively simplifying the model, basic stability information could be derived. Specifically, what was of interest was the angle and distance that the boat lists once a person on the boat shifts to the outer edge of the boat. In order to further simplify the calculation, the boat was modeled as a transverse 2D plane of the cross-section of the boat. Several parameters were required to first be determined in order to calculate overall stability calculations. The first parameter was the center of gravity. In order to determine the center of gravity of the boat, the weights of major boat components needed to be taken into account as well as the weight of a person. The weights that were assumed for each of the major components, as well as for the person, are shown in Table 6. Note that the center of gravity of the boat was the key component affecting the stability of a boat. In essence, the lower the center of gravity of the boat, the more stable the boat was when floating and when loads were shifted within the boat. The second parameter was the center of buoyancy of the boat that was found using relationships developed in “Ship Stability for Masters and Mates.” Using naval architecture theory along with these two parameters and basic trigonometry, the angle of list and distance that the boat tips with shifting masses could be calculated. Table 6: Component weights. COMPONENT WEIGHT [LBS.] BOAT SIDES 90 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 22 BOAT BOTTOM 250 MOTOR 60 FRONT, WINDSHIELD, HATCH 140 FLOOR 100 HUMAN 200 Assuming no external forces, such as waves or wind, and that the person was located at the centerline of the boat, the boat sits transversally flat in the water with no list. In this scenario, the centers of gravity and buoyancy of the boat are vertically aligned. However, when the person shifts to the outside of the boat, the boat lists or tips in that direction. The boat lists in the direction that the person moves due to the fact that the movement of the person causes the center of gravity of the boat to be shifted in that direction. The boat has a listing moment until the center of buoyancy changes and aligns with the new, shifted center of gravity. Under this methodology, Figures 3 and 4 were derived showing both the angle of list as a function of boat bottom width and the distance that the side of the boat sinks into the water as a function of boat bottom width. 20 18 Angle of List [deg] 16 14 12 10 8 6 4 2 0 30 35 40 45 50 55 60 65 Bottom Width [in] Figure 3: Angle of list as a function of the bottom width of the boat. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 70 75 23 7 6 Tip Distance [in] 5 4 3 2 1 0 30 35 40 45 50 55 60 65 70 75 Bottom Width [in] Figure 4: Distance boat lists into the water as a function of width of the boat. From Figures 3 and 4, it was determined that a boat bottom width between 4 and 5 feet should not be an issue from a stability standpoint. Ideally, the boat would be designed with a bottom width closer to 5 feet because of the added stability. With the boat designed as such, if a person moved from the centerline of the boat to the outer edge of the boat, an angle of approximately 6 degrees would be incurred, resulting in a 3 inch downward shift into the water. It was deemed by the team that this was an acceptable displacement. Finally, it was worthwhile noting that the calculations performed are a simplified theoretical approximation of the actual situation. In the realm of modern naval architecture, advanced and sophisticated computer modeling is used to model and evaluate the stability of boats in all planes and axes of motion under an extremely large number of conditions. While the model used to derive Figures 3 and 4 is very basic, after correlating these calculations with information provided by boat owners with similar size boats, the calculations appear to provide an acceptable approximation of the actual situation. Since one of the major constraints for the Expedition Camper was that it must be lightweight, an analysis was done to determine the overall weight of both the camper and the trailer. The first part of Table 7 shows the approximate weight of major components on the camper and boat portion of the Expedition Camper. Note that this was a dry weight, meaning, it does not include accessories such as furnishings and other equipment and supplies. The second part of Table 7 shows the approximate weight of the trailer portion of the Expedition Camper. The importance of this analysis laid in the fact that it showed that the project was feasible from a weight standpoint. As an estimate, the team saw that the weight of the camper portion of This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 24 the Expedition Camper was less than the max design constraint of 1,500 pounds. Furthermore, the total weight of the camper was less than the max tow capacity of 2,000 pounds, from Table 4, of the typical vehicle that would tow the Expedition Camper. Table 7: Weight calculations. Assembly Component Material Weight [lbs.] Hull Aluminum 400 Base Aluminum 150 Top Steel/plastic/cloth 50 Steel/cloth 100 Floor Wood 100 Hatch Steel/glass 60 Wall/windshield Steel/glass 80 Outboard motor N/A 60 Battery N/A 30 Fuel Tank N/A 30 Boat/Camper Roll bar 1,060 Sum Trailer Trailer frame Steel 400 Leaf springs Steel 60 Shocks Steel 10 Jacks Steel 30 Steps Steel 15 Hitch Steel 10 Wheels/tires N/A 125 Sum 650 Sum 1,710 Total 5.1.2 Launch Parameters An important aspect that was considered in the design of the Expedition Camper were factors affecting how it was launched into the water. Typically, a boat launch or ramp is used to put a boat into the water. The purpose of the boat launch is that it quickly increases the depth of the water with respect to distance from This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 25 the edge of the body of water. In other words, a boat launch allows a boat to be easily removed from its trailer. However, the Expedition Camper was capable of functioning on bodies of water which were out in the wilderness where no boat launches were present. The Expedition Camper, therefore, was designed to launch without a boat launch. Basic buoyancy calculations revealed that that the V-bottom of the camper would rest at 6 inches below the water line when it was floating. Figure 5 shows the relationship between the distances that the camper sinks into the water and the weight of the camper. Note that this calculation assumes a bottom area of the camper of approximately five feet wide by 10 feet long. The Expedition Camper sat relatively high off of the ground for traversing rough terrain, but it was also required that the camper needed to be low to the ground for ease of launching it into the water. The solution to this conflict was to build an air bag suspension system for the trailer. Not only does this type of suspension provide the necessary adjustments, it also provides a smoother ride for traversing rough terrain. Note that the suspension will be discussed more in a later section of the paper. Camper Weight [lbs] 2500 2000 1500 1000 500 0 0 1 2 3 4 5 6 Depth [in] Figure 5: Distance Camper will sink into water based on weight. Initially, the launch parameters were calculated based on the idea that the hull of the camper would be a flat bottom and that the suspension of the trailer would be leaf springs. Due to the large off-road tires being used, the Expedition Camper sits high on the trailer, approximately two feet above ground. Assuming a scenario where the trailer enters the water with the bottom of the lake being flat, the Expedition Camper required a minimum water depth of 30 inches for a successful launch. The water level after launch is the water line that the camper floats at when in the water. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 26 Figure 6: Camper height dimensions for launch parameter reference. As previously mentioned, the worst case scenario was a flat lake bed, requiring a 30 inch depth of water at the tires to launch. This scenario was very unlikely, as most lake bottoms have a grade to some extent. The distance from the hitch of the trailer to the wheel axle was 11.5 feet, and the distance from the wheel axle to the back of the camper was 4 feet. Based on these dimensions, a one degree incline of the lake bottom results in the back of the camper being approximately 3.25 inches below the hitch height. Furthermore, each additional degree of incline dropped the back of the boat an additional 3.25 inches. In regard to the degree of incline, the back of the camper dropped 0.84 inches below the axle height per degree of incline. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 27 B A Y X 138” θ 48” For θ=1 degree: Y = 138” x sin (1) = 2.41” X = (138” + 48”) x sin (1) = 3.25” X – Y = 0.84” therefore for every degree incline, the change in height between locations A and B is 0.84” Figure 7: Dimensions and calculations to find height difference between points A and B. For example, if the lake bottom had a ten degree incline, the back of the camper would be 8.4 inches below the part of the camper in line with the axle. Due to this, any incline greatly increases the ease of launching the camper. The back of the camper sat lower compared to the rest, and therefore entered the water first and reduced the upward force that the camper experienced from the cross-beams of the trailer. A typical scenario assessed involves a 5 degree grade for the lake bottom and a 12 inch bank on the sides of the lake. Based on these values, the water depth required to launch the camper is 22 inches at the location of the axle. 5.1.3 Boat Frame 5.1.3.1 Tub Section The tub design of the camper was one of the most crucial components. Not only does the tub portion form what would be thought of as the camper portion, the place where the living space is found, it also was the general aesthetic makeup of the unit making it look more like a camper than a boat. The tub had a width of 59 inches and a length of 100 inches. Note also that these tub dimensions were the same as those found on a Jeep Wrangler (years 1997 through 2006), thereby fulfilling the criteria that the camper was aesthetically pleasing. Furthermore, a camper tub shaped and dimensioned after the Jeep Wrangler gives opportunity for other Jeep-based accessories to be applied to the camper, such as the soft-top. Figure 8 below shows the overall styling as well as approximate dimensions for the tub portion of the camper. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 28 Figure 8: Approximate dimensions for Jeep-styled tub portion of camper.8 5.1.3.2 Hull Initially, the team intended to purchase an aluminum boat and then modify it to fit their desired specifications, such as increasing strength in addition to changing the aesthetics to make it look more like a camper. The plan was to install a Jeep tub into the aluminum boat, but it was determined that this option would not be the best way to achieve the objective of making the camper aesthetically pleasing. http://s213.photobucket.com/user/jscherb/media/Camper/DinootWide1_zpsf2cd9bcf.jpg.html?sort=3&o =145 8 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 29 Figure 9: Approximate boat hull dimensions.9 After an extended search for a used boat yielded no acceptable results, the team decided it would be best to design and manufacture the entire boat from aluminum sheets. The primary reason why a suitable used boat was not found was due to the fact that most aluminum boats containing the width and aesthetics that the team desired, did not fit the team’s objectives well. While some boats were found that would have been wide enough to fit the team’s specifications, these boats were also significantly longer than 16 feet in length, which would have been undesirable in off-road situations, and in addition were quite expensive. As a result, team decided that they could develop a better end product from both an engineering and cost standpoint by starting fresh. 9 http://chicago.craigslist.org/nwi/boa/4225400901.html This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 30 Figure 10: Frame of the camper. The team chose to design the entirety of the camper using SolidWorks in order to ensure that the team’s form and function objectives for the camper could be met, prior to building the prototype. SolidWorks was used, as opposed to other 3D CAD packages, because of the familiarity of the team with it, as well as the availability of the professional version of the software package at one of the team members’ place of work, allowing the team to develop detailed prints of their design. The hull of the boat was designed as a 7 degree incline. 5.1.4 Front Wall Section The team decided that adding a front wall in the Expedition Camper would provide a way for it to be better used as a camper. The front wall was designed to have a door in the center with two walls on each side. The walls and the door each had a Plexiglas window in them. The top section of the wall was a modified jeep windshield, and the bottom section was manufactured from sheets of aluminum. The door was also made out of aluminum. Several different ideas were considered for how the door would open. The intention for the door was to have it be easy to open, out of the way, and aesthetically pleasing. The initial design had the door hinging on its side. This feature allowed for it to stay open and the user to walk between the front and back portion of the camper without having to duck through the doorway. This idea was later rejected and it was decided that a door hinging upward would be the best option for several different reasons. First, the door has a bend in it, so it would have to hinge to the side on either the bottom portion or the top portion. It was determined This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 31 that this would not be aesthetically pleasing which lead to the final design of hinging the door on the top and swinging upwards. Furthermore, the soft top needed to be latched to the front wall, so it was decided to leave the entire top portion of the windshield, instead of cutting it in the middle. As a result, the user would have to duck under the top part of the windshield to pass through the doorway, so having the door swing to the side and out of the way was no longer useful. With this in mind, having the door hinge upward was preferred over having it hinge to the side. Figure 11: Front wall in camper frame. The door was designed so that the user can get into the tub portion of the camper when the soft-top is up. This way, when the Expedition Camper was being used for sleep and other camper purposes, the user may move freely in and out of the camper through the use of the door. The door was approximately 2 feet wide, and each side wall was approximately 1.5 feet wide. Rubber gaskets were placed on flanges that stand 1 inch out around the entirety of the doorway so that a proper seal could be made between the door and the rest of the front wall. 5.1.5 Soft Top and Mount Another key component in the design of the Expedition Camper was the top. The top of the camper must be easily removed to allow for standing of occupants when the camper was used in its boat configuration. However, not only did the top need to be easily removable, it also needed to be lightweight in order to satisfy the weight constraints of the design. Under these criteria, it was determined that a top made of waterproof cloth would be the best option, both from a lightweight and a simplicity point of view. Since the team desires to incorporate Jeep-styling into the design, a Jeep soft top was the logical solution because it satisfies all design constraints. While some modifications to the top were required to fit the exact This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 32 application, the Jeep soft top was the perfect candidate. A 2004-2006 Jeep Wrangler LJ soft-top fit with the current design dimensions and would only require modification of the side windows. Furthermore, the soft top involved a framework that allows it to be easily removed by folding down. On a Jeep Wrangler, this framework is connected to the roll bar. Initially, connecting the soft top to a roll bar inside of the camper appeared to be the logical option for installing the soft top. Figures 12 and 13 show approximate soft-top dimensions. Figure 12: Approximate top dimensions.10 10 http://www.netcarshow.com/jeep/2004-wrangler_unlimited/800x600/wallpaper_04.htm This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 33 Figure 13: Approximate roll bar dimensions.11 Throughout the design process it became clear that a roll bar would be less beneficial than had originally been thought, because occupants would not be in the camper while it was being pulled therefore losing the safety merit. Additionally the roll bar would be an additional obstacle when the camper was being used as a boat and the top is down. Since the height of the roll bar from the camper floor was rather small, it would be in the way of the user when they stand in the boat, therefore, a new design for the mounting system was made. Traversing tubes were installed where the roll bar would be located allowing the user to hide the supports in the wall while the top is down. From both a functionality and aesthetics point of view this was a quality improvement. 5.1.6 Motor and Motor Mount The motor mount was designed by the team and the motor was selected based on several boat dimensions. 5.1.6.1 Motor Determining the power needed for the motor required some preliminary standards. The power required depended on the intentions of the camper; namely if it was desired to be used to travel quickly across bodies of water or to be more focused on casually trolling across the water. Due to the fact that the camper was designed to be used for leisurely activities like fishing, it was assumed that the camper would not be required to travel quickly across water. Research led to the basic rule for boating that 5 pounds of thrust is needed 11 http://www.netcarshow.com/jeep/2004-wrangler_unlimited/800x600/wallpaper_08.htm This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 34 for every 200 pounds of boat weight. The team determined that the boat would weigh no more than 1500 pounds. Calculating the force required with that weight meant that the camper will need 37.5 pounds of thrust. The main factor that went into choosing the motor was the length of the back wall of the camper. This length of 27 inches was from the top lip down to the middle of the V-bottom. This length was quite high compared to typical 12 foot aluminum boats, so instead of using a short shaft or long shaft motor, an extra-long shaft motor was required in order to correctly align the propeller below the boat bottom. Based on these specifications, a Johnson 9.9 hp extra-long shaft was being considered for the motor to be used for the camper. The team considered building a storage space on the front of the trailer for the motor to be stored in when towing the camper. Due to the limited budget, the team did not implement this into the prototype but would suggest it as a possible improvement to pursue. 5.1.6.2 Motor Mount Early on in the project it was decided to build a motor mount on the back of the camper that the motor could be mounted to. A few benefits of having a mount were that the motor is not in the way of the soft top when it was latched to the back wall of the camper, the motor could be more easily taken off and on when necessary, and there was more space inside of the camper with the motor and gas can on the mount. In designing the mount, the team had to make sure that the motor would correctly align with the bottom of the boat depending on where the mount brackets were placed on the back panel of the camper. The team decided to have the center of these brackets be two inches below the top of the wall in order to have close to 25 inches between the top of the mount and the bottom of the boat. Aesthetics also played a big role in the design of the motor mount. The team wanted the mount to be modern looking and fit in with the rest of the camper look. The width of the mount was chosen to be 45 inches and the height to be 12 inches. The mount was made out of 1.5 inch OD steel tube with 4 crossbars and a 1/8 inch steel plate in the middle for the motor to be mounted on. The plate of the mount was approximately 7 inches off of the back of the camper. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 35 Figure 14: Motor mount on back of camper frame 5.2 Trailer The second major component from a design standpoint was the trailer. The trailer frame required design and analysis in order to properly fit the camper features, such as the V-bottom. Other major design characteristics possessed by the trailer include fenders, airbag suspension, tie down points, and a winch. 5.2.1 Trailer Frame In the initial stages of the project the team wanted to buy a boat trailer and modify it to fit the overall shape of the boat hull. After finding what was believed to be the best option for the purchase of a trailer the team soon decided that it made more sense to fabricate a trailer from scratch. Using SolidWorks to design the trailer the team was able to model a trailer with the desired profile and strength. An FEA model was also created to make sure the design met the strength requirements. This model is discussed in the FEA section of the report. One of the main issues that came up in the modification of a prefabricated trailer was the way the team wanted the V-bottom shaped hull to sit on the trailer. Most boat trailers use bunks that sit up high for the boat to rest on. Our design uses V-shaped cross members made from 3 inch x 2 inch steel tubing with 1/8 inch thickness with UHMW strips on top to hold the boat. This way the camper can sit down in the trailer, hiding its boat features and making it look more like a camper. Several other modifications would have been needed to install the airbag suspension system the Expedition Camper uses. By making the trailer from scratch, suspension brackets and airbag mounts could easily be installed without many issues. The trailer frame itself was made from 4 inch x 2 inch steel tubing with 1/8 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 36 inch wall thickness. The airbag mounts were made from ¼ inch thick steel plates to ensure that the integrity of the trailer will not be compromised. 5.2.2 Hitch Since the goal of designing the camper was to make it as rugged as possible, the trailer hitch needed to match this goal as well. It was determined that a regular, conventional trailer hitch will not suffice for this project because of its lack of mobility. A regular trailer hitch has only one degree of freedom that allows it to rotate around the ball it is connected to. In order for the hitch to be able to fully function as needed in an off-road situation, it was determined that the hitch needed to have three degrees of freedom. Two options evolved from this issue; build one or buy one. After doing some research, an appropriate hitch was found that could be purchased. Lock N’ Roll12 designs and manufactures many types of off-road hitches for trailers. Figure 15 shows an example of one of their particular hitches. Figure 15: 501 with a 510 off-road trailer hitch by Lock N’ Roll13 Unfortunately, the price of this hitch was just over $200 which was too large of an expense given the project’s budget. Further research showed that $150-$300 was a fairly common price range for these style hitches, and building one was much cheaper than buying one. Due to the large differences in prices, the 12 13 www.locknroll.com https://locknroll.com/gallery/gallery-category/ This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 37 team decided to manufacture a hitch to decrease expenses. A search of multiple trailer forums proved effective in finding a design for the necessary hitch. Using SolidWorks, a model for the hitch was then created, and is shown in Figure 16. Figure 16: Solid works model of three axis hitch. This hitch was designed by Jeff Scherb and has been used with his consent. This hitch has the ability to rotate around the three axes of a standard three-dimensional coordinate system. The hitch was a critical aspect to allow the camper to go off-road, therefore the team determined that an analysis of the hitch was warranted. Rather than perform an extensive finite element analysis of the entire hitch assembly, the analysis was simplified down to determining the strength of the pins and bolts in the hitch. Since the diameters of the pins are smaller to the diameters of the bolts and are made from the same material, the pins would be the first part to fail. Since the pins would be in shear and not in tension, the shearing force needed to break the pin was calculated using the tensile strength of steel and the cross sectional area of the pin. As previously stated, the tensile strength of steel is approximately 58,000 psi. Assuming that the shear strength of a material is roughly equal to one half of the tensile strength of a material, the shear strength of steel is approximately 29,000 psi. Using this value and a 5/8 inch diameter pin, the shearing force required to fracture the pin was calculated to be 8,900 pounds. This force is much higher than the anticipated total weight of the combined trailer and camper, which is approximately 1000 pounds, thus making the hitch safe to use. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 38 5.2.3 Suspension One of the key areas of the trailer on which the team focused was the suspension design. Typical boat trailers have a leaf spring suspension system that absorbs various loadings and vibrations, resulting in a smoother, less stress-intensive ride. For the application of this camper, the team looked at two different suspension styles; leaf springs and air bags. 5.2.3.1 Leaf Springs Most boat trailers use leaf springs for the suspension system because leaf springs are inexpensive, readily available, and easily mountable to a trailer frame. However, they do not allow for any vertical adjustment of the trailer, which could be an issue when trying to launch the Expedition Camper in a location where there is not a standard boat launch. Figure 17 provides an example of a typical leaf spring suspension system on a trailer. Figure 17: Leaf spring suspension system.14 The leaf spring form of suspension was what the team intended to use on the trailer due to simplicity as well as budget constraints. Later in the semester it was decided that air bags would be a better option, but this was after leaf spring calculations were performed. As stated earlier in the report, one of the objectives for the Expedition Camper was that it would have the ability to survive a 1 foot drop. To meet this requirement, calculations were performed on leaf springs to determine the level of stress that they would experience in various scenarios. The first calculation was used to determine the maximum stress that one of the leaf springs would experience if subjected to a dead load of 1000 pounds. This resulted in a maximum stress of 85.9 MPa. The second calculation was used to find the maximum stress that would be experienced by one of the leaf springs if loaded with 1000 pounds and subjected to a sudden drop of 1 foot. This resulted in a maximum stress of 482.5 MPa. Because the yield 14 http://www.personalwatercraft.com/products/what-to-look-for-in-a-pwc-trailer-1159.html This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 39 strength of common 5160 grade leaf spring steel is 670 MPa, the trailer leaf spring has a safety factor of 1.39 in the event of a 1 foot drop. Figures 18 and 19 shown below, provide a summary of the impact forces and stresses experienced by a leaf spring when subjected to different drop heights under the assumption of a 1000 pound load on the spring. 30000 Impact Force [N] 25000 20000 15000 10000 5000 0 0 0.2 0.4 0.6 0.8 1 1.2 1 1.2 Drop Height [ft] Figure 18: Force on leaf spring as a function of drop height. 600 Impact Stress [MPa] 500 400 300 200 100 0 0 0.2 0.4 0.6 0.8 Drop Height [ft] Figure 19: Stress on leaf spring as a function of drop height. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 40 5.2.3.2 Air Bags While the team had initially intended to use a leaf spring form of suspension for the trailer, this plan changed when Air Lift Company, based out of Lansing, Michigan, graciously agreed to donate a set of suspension air bags for the project. This was an exciting addition to the project from several aspects. Not only do the air bags provide a smoother ride off-road than the leaf springs, they also allow for the height of the trailer to be adjusted. Thus, the height of the trailer could be raised for traversing over large obstacles, and also lowered to allow for ease of launching the camper in remote locations where no boat launches are present. After researching several air bag suspension designs currently on the market, the team set out to design and build one suited to their trailer. The team chose to build a trailing-arm style suspension, similar to the one shown in Figure 20. The picture shows independent arms on each side of the trailer for additional flexibility when driving over rugged terrain. However, the air bags can also be connected to a single axle without being cut. While driving, the air bags are filled with compressed air to allow fluid movement. The air bags can also be deflated, by releasing the air, to lower the whole trailer by several inches. Figure 20: Air bag suspension system.15 The team began by designing the trailing arms that attach the axle to the frame. Based on research, material availability, and desired strength characteristics, it was decided that the arms would be made out of 2 inch by ¼ inch wall square tubing. Furthermore, in order for the suspension to be extremely robust, the geometry of the arms was developed so as to minimize twist and deflection of the arms when traversing over rough terrain. The entire trailing arm suspension set up was modeled in SolidWorks in order to aid in this design. Using research in conjunction with the SolidWorks model of the trailer, it was determined that the arms should be approximately 2 feet in length. Triangulation and bracing was an important feature in designing 15 http://www.naxja.org/forum/showthread.php?t=1002676 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 41 these arms in order to make them extremely stiff so that they would not bend or deflect when subjected to large forces. Figure 21 below shows a SolidWorks model of one of the arms. The bottom ends of the arms were notched and welded to the axle tube, while the top ends of the arms, each designed with two bushings spaced a large 16 inches apart, were bolted to a cross member that was welded to the trailer frame. Because of their ready availability, ½ ton Chevrolet leaf spring bushings were used to connect the arms to the cross member of the trailer, and thereby damp vibrations experienced by the trailer. The cross-member, attaching the arms to the trailer, was constructed out of 2 inch by 3 inch by 1/8 inch wall steel tubing, and the arms were attached to the cross member using laser-cut, ¼ inch steel plates. Finally, the air bag mounts and shock tabs were made from laser-cut, ¼ inch steel plates. Figure 21: Arm for air bag suspension. Several calculations were performed with regard to the air bag suspension. In order to analyze the air bags, they were modeled as thin-walled pressure vessels. The maximum stress experienced by the air bags when the bags were at an internal pressure of 30 psi was a stress of 125 psi due to the axial load of the trailer and camper as well as the internal pressure of the air bags. The air bags are rated for a pressure of 600 psi, which is far from what they will experience when riding with an internal pressure of 30 psi. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 42 5.2.3.3 Air Suspension Control From a control standpoint, it was determined that a pressure regulator connected to an air tank would control the pressure of the air bags. This would allow the height of the trailer to be raised or lowered by the bags that have an overall stroke of 9.7 inches. 5.2.3.4 Axle, Tires, and Shocks Based on the width of the trailer frame, a standard 76-inch wide, 3500 pound capacity trailer axle was selected and purchased from Holland Trailer in Holland, Michigan. It was further determined that large 35 inch tires would be used for the trailer because of the off-road capability that they added to the project. The tires were pre-owned by the team and therefore did not need to be purchased. As specified by the manufacturer, the air bags have a minimum height of 2.8 inches and a maximum height of 12.5 inches. At ride height, the air bags are approximately 6 inches tall, which when combined with the 35 inch tires, causes the trailer to have a height of 28 inches above the ground. On the other hand, when fully deflated, the trailer has a height of 22 inches above the ground. Note that when fully deflated, the trailer frame rests on a set of bump stops designed to contact the axle in order to protect the air bags. Finally, a set of shock absorbers were added to the suspension design in order to dampen vibrations experienced by the suspension. 5.2.4 Tie Down Points During the design process several methods for attaching the boat to the trailer were considered. These ideas included; cutting slots in the trailer frame for tie down hooks to grab onto, welding slotted angle brackets to the trailer, and welding eye bolts to the trailer. A consensus was reached to use the eye bolts because of their simplicity and size. One inch inner diameter eye-bolts were welded at the back end of the trailer frame. These bolts are strong enough to handle any forces on them that may result from the camper bouncing around while being towed off-road. The camper will remain secured to the trailer through the use of the two tie down points in the back and the winch in the front. 5.2.5 Straps In order to ensure that the camper properly sits on the trailer, a set of ratchet straps was purchased. These straps had to be strong enough to hold the camper in place while being pulled over rough terrain. This meant that a lot of force will be acting on the straps, therefore proper size was considered. The team determined that if the camper were to bounce excessively a strap would feel the entire weight of the camper, which was determined to be approximately 1000 pounds. By using this information the team decided to purchase two straps that are each rated for a working load limit of 1200 pounds, so that each exceeds the weight of the boat. This provides a large safety margin and ensure that the boat will stay secured to the trailer. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 43 5.2.6 Trailer Jacks When the Expedition Camper is being used on land for camping purposes, it will require support for when a person is inside of it. Four jacks will be included with the camper to place at each corner in order to stabilize it, similar to typical campers used today. Because off-road tires will be used for the camper trailer, the camper will be sitting fairly high off the ground. The axle of the trailer will be 17 inches above the ground, and the base of the trailer around 5 inches above the axle, making the required height for the jacks to be a minimum of 22 inches extended. Two different types of jacks were considered for the Expedition Camper: stacker jacks and scissors jacks. Images of each are shown below in Figure 22.16,17 Figure 22: Stacker jacks and scissors jacks. Stacker jacks are fairly cheap, but no sizes have been found to be adjustable to more than 17 inches. Scissor jacks on the other hand are more expensive, but do have a larger variety of ranges, some of which being able to extend to more than the 22 inches required. One consideration was having blocks to be placed under the stacker jacks, giving them the extra 5 inches needed. This option was decided against because it would not be as stable and would take up more storage space. After discussing the available options, it was decided that the best option is to use 30 inch scissors jacks, costing around $100 for the pack. These were the best option because, although they cost more, they provide a safer and more secure foundation for the camper, adhering to the design norm of trust. Due to budget constraints, the team decided not to go forward with purchasing the trailer jacks. The jacks are a potential future addition to the Expedition Camper. 5.3 Finite Element Analysis In order to determine if the design would be feasible, basic calculations and conceptual drawings were done. The size of the trailer and boat determined the overall dimensions of several other pieces in the design. The team set a baseline parameter for the trailer to be able to withstand a one-foot drop, simulating what may 16 17 http://www.etrailer.com/Trailer-Jack/Stromberg-Carlson/JSC-30.html http://www.etrailer.com/Trailer-Jack/Ultra-Fab-Products/UF48-979003.html This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 44 be encountered when running over a rock, and remain structurally intact. The team also performed stability and buoyancy calculations to determine how the camper would perform on water. Under the assumption of impact forces, FEA analysis was used to evaluate the structural integrity of the design. Finite Element Analysis (FEA), using Algor Multiphysics Simulator, was deemed to be a crucial tool in developing the design. Approximate models of the camper and trailer were developed to determine if the designs would hold up under impact loads of 6,000 pounds. After determining that the trailer and camper could, in fact, withstand these forces, more refined models were developed and simulated in the FEA program based on the designs the team created. 5.3.1 Camper/Boat FEA Initial FEA models of the camper were constructed based on the fact that the team would be using bunks in order to set it on the trailer. Figures 23 and 24 show the maximum stress and displacement of the camper under what was deemed worst case scenario. This scenario puts a force of 3,000 pounds on the camper and the analysis shows that, with aluminum material, the design will hold and does not displace enough to compromise other parts of the design. Figure 23: Boat stress FEA. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 45 Figure 24: Boat deflection FEA. From this the team decided to continue to refine the design of the camper itself, knowing that we could build a unit that would meet the standards set for it. After continuously improving the design of the camper, which included the addition of braces along the flooring, a final design was reached in which another FEA model was created to double check the strength and durability of the camper. Figure 25 shows the stress analysis for the final camper design. Unlike the first model, the camper does not rest on bunks, but instead rests on ¼ inch UHMW strips mounted to steel 3 inch x 2 inch cross beams. The final model simulates the worst case scenario of the weight dropping down all at once. Again this would be the 3,000 pounds used earlier, only it would be dispersed over a different surface area than that of the original model. The design changed somewhat so the model only showed and maximum stress of 400 psi. This is much lower than the stress of 5052 aluminum and will be able to withstand the required impact loads. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 46 Figure 25: Final camper/boat FEA model. 5.3.2 Trailer FEA In order to ensure that everything in the design is safe during travel, FEA analysis was done on the trailer. The team made sure that the trailer could withstand the impact forces resulting from traveling over rugged terrain. If the trailer were to fail, the whole unit would be suspect to breaking. Using impact force equations, the team calculated that if the trailer were to be pulled over a one foot dropoff, the force experienced by the trailer would be equivalent to about 6,000 pounds of static load with a safety factor of 2. The same method was used for the trailer design as was used for the boat. Rough models were simulated up front to make sure a basic trailer design would meet the team’s goals. According to the first FEA model, the maximum force experienced by the trailer was 68,000 psi. Note this assumed a worst case scenario of one wheel absorbing all the impact. The ultimate tensile strength of ANSI 1080 annealed steel is 89,250 psi. Therefore, according to this simulation, the design should not fail. The team also made sure the displacement would not be excessive and compromise other parts of the unit. The maximum displacement of the trailer itself does not exceed 1.12 inches according to the model. Both the strength and displacement diagrams are shown below in Figures 26 and 27. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 47 Figure 26: Trailer stress FEA. Figure 27: Trailer displacement FEA. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 48 After determining that a trailer design similar to the first crude models would work, further refinement went into the trailer and more detailed drawings were made. Once the team reached a final design, another FEA simulation was performed on the final design. Another additional simulation was also completed on the suspension brackets because this is the main connection between the frame and axle of the trailer and would be where the highest stresses would occur. Figures 28 and 29 below show the air bag bracket FEA and trailer FEA respectively. Figure 28: Airbag mounting bracket FEA simulation. The simulation above applies a maximum load of 6,000 pounds on the bottom of the bracket. The model shows that a maximum stress of around 27 ksi will be reached. This stress is well below the yield stress of the steel, so the team is confident that the airbag mount will hold up under strenuous conditions. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 49 Figure 29: Stress FEA of final trailer design. Again a 6,000 pounds was applied in the above model, but the force was applied downward to the cross members of the frame. The tongue of the trailer and the locations in which the airbag mounts are located were fixed to simulate a realistic loading. According to the model, the maximum stress on the trailer will reach 24 ksi which is below the yield strength of steel, therefore, the design will meet the required criteria. 6 Testing In order to ensure that the final product meets the standards set forth, multiple tests are going to be performed on the finished product. One area of testing was the safety for the user in different functions of the Expedition Camper. More specific tests were planned to be performed to confirm if the team’s objectives were met. These tests included a drop test, a launch capability test, and a stability test. 6.1 Safety Safety was the team’s biggest concern when it came to the actual operation of the product. In order to ensure that the final product was safe for users, the team planned to perform basic tests that aimed at possible safety risk areas. These included the procedures of launching the unit into the water, hooking up the hitch to the vehicle, setting up and taking down the soft-top, moving in and out of the camper, and typical use of operating the motor. During the test each member planned to document any concerns or ergonomic problems that arose in the process. Along with this, the team planned to simulate a typical outdoor adventure where each feature would be used. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 50 6.2 Initial Testing Testing had not yet been performed as the camper was not completed until the day of the senior design open house. If the team were to continue with testing, there would be three tests that the team would like to have performed. 6.2.1 Drop Testing The drop test would involve towing the trailer with the camper on it over a one foot drop-off. The test would be performed multiple times, with inspection of the trailer and camper occurring after each trial. If there was not any notable damage to the camper or trailer, the unit would have passed the test. 6.2.2 Launch Testing Launch testing would involve launching the camper in several different areas. The purpose of this test was to get an idea of how easy it is to launch the boat in various water depths and shoreline conditions. The testing would be performed by one person. The person must have easily and safely been able to remove the camper from the trailer into the water as well as load the camper back onto the trailer. 6.2.3 Stability Testing Stability testing would involve getting the camper out on the water and testing its stability in two cases, when traveling and when at rest. Testing would occur by moving to one side of the boat and approximating the amount of list that resulted in this shift. The distance of tilt would be measured while the camper was at rest by driving a stake into the ground next to the boat and then marking on the stake where the camper edge lies before and after the person shifts to the side. The testing while traveling would require an estimation for the distance of tilt as the camper would be moving too fast to get a measurement in this way. 6.3 Modifications If any of the tests failed the camper and trailer would have been analyzed in order to figure out the reason for failure. If possible, modifications would have been made so that the camper and trailer would not fail in the given scenario. 7 Business Plan 7.1 Market Competition There is nothing on today’s market that serves the same purpose as the Expedition Camper. However, there are currently some campers designed to be hauled to places of which a typical camper or boat cannot go. The unique aspect of the Expedition Camper is that it serves multiple purposes as a camper and a boat. For the purpose of studying the marketability of the product, the team considered the Expedition Camper as part of the market of durable off-road campers. The fact that it can be used as a boat was considered market differentiation and an expansion to the market of durable off-road campers. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 51 The off-road campers currently on the market range greatly in complexity. The complexity greatly depends upon how many accommodations are built into the camper. Three major off-road campers and their selling prices are shown in Table 8. Table 8: Off-road campers and their base purchase prices. TRAILER BASE PRICE [$] MOBY 1 XTR18 16,500 SO-CAL TEARDROPS 14,995 THE KRAWLER19 ADVENTURE TRAILERS TEARDROP 7.2 13,852 20 Break-even Analysis To estimate the approximate cost of producing the Expedition Camper, research was done regarding the fixed and variable annual costs that correspond to the various components of the camper. The costs of each component are shown in Table 2 of Section 2.3. To determine a production cost estimate, all of the costs that corresponded to each camper were recorded, as well as all of the annual fixed costs such as building rent, machinery, and insurance. A table of these costs is shown below. Table 9: Cost per camper and annual fixed costs. PRODUCTION COST ESTIMATE Description COST PER CAMPER ESTIMATED $2,000 LABOR RAW MATERIALS $2,270 MARKETING $1,200 DISTRIBUTION $1,500 ANNUAL FIXED COSTS UTILITIES $40,000 WORK AREA RENT $75,000 INSURANCE $10,500 PATENT $10,000 PROTOTYPE $30,000 MACHINERY $100,000 DESIGN $100,000 Total Cost 40 hr @ 50$/hr $6,970 Description Total Cost 10,000 @ $7.5/ft2 10% of building/equip. cost $365,500 18 http://moby1trailers.com/moby1-xtr/ http://www.socalteardrops.com/page.php?p=22 20 http://www.adventuretrailers.com/teardrop.html 19 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 52 In order to choose a reasonable price to sell the Expedition Camper, break even analysis was performed to find the minimum required sale price to break even. Below is a summary of the costs and sale price required to break even based on a production rate of 30 units per year. Table 10: Break Even Analysis for Expedition Camper. BREAK EVEN ANALYSIS ANNUAL PRODUCTION ANNUAL FIXED COSTS COST PER VEHICLE TOTAL ANNUAL COST BREAK EVEN SALE PRICE 30 $365,500 $6,970 $574,600 $19,153 8 Conclusion At the beginning of the year, the team developed the idea of a unit that can be taken off-road and used as both a camper and a boat. Several objectives were established for the Expedition Camper to meet. Over the final two semesters at Calvin the team designed and manufactured the Expedition Camper in pursuit of the goal of dual functionality. The camper’s complex design and robust construction allow it to be pulled over large obstacles encountered on off-road trails as well as be removed from the trailer and placed into a pond or lake so that it can traverse across water. With clever design work, detailed engineering calculations, and innovative construction, the team was able to build a unit that has proven to be capable of being towed offroad and used for various purposes as a camper and a boat. If further work were to be performed on the project or if a second prototype were to be developed, it would be worthwhile to make several changes and additions. One addition that would be beneficial to the project would have been to design and install longitudinal bracing in the boat bottom to prevent the bottom from becoming wavy when welded. A second addition that should have been implemented was a door handle. The door handle should have a cam latch that could lock the door down. Gasket should also be added to the flange of the front wall so that a proper seal is made between the door and the wall. An air tank or compressor would also be mounted on the front of the trailer so that the air bag suspension may be cycled when out in the wilderness. One final addition would be that the inside should be furnished with various accessories needed for camping and boating purposes. One thing that the team would have done differently in the design was to lower the winch mount. It rested close to level with the tie down of the boat, but should have been lower than the tie down so that it could This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 53 pull the boat downward when securing it to the trailer. Another change that the team would have made was to either shorten the back of the camper or implement a steering and throttle system so that the camper may be driven with the top up. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 54 9 Acknowledgements The team would like to acknowledge the following people for their support and help on the project. Ned Nielsen – Engineering Professor and team advisor Terry VanHaitsma – Premier Metal Products, fabrication and welding Phil Jasperse – Metal shop instructor and manufacturing mentor Josh Noling – Progressive Surface Jordan Hiemstra – Industrial Designer Dave Hiemstra – Painting Nel Osterwald – Custom canvas work Jeff Scherb – Aftermarket Jeep parts designer Dave Kramer – Cascade 4WD Nate Holstege – Preferred Machine, laser cutting Megan Smith – Schupan, aluminum supply Jeremy Hart – Airlift, airbag donation Nick Capinski – Eastwood Company, primer donation Wyrick’s – Paint supplier This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 55 10 Bibliography Cabela's World's Foremost Outfitter. N.p., n.d. Web. 28 Nov. 2013. <http://www.cabelas.com/product/Trolling-Motor-Buyers-Guide/532011.uts>. Derrett, D. R., and Bryan Barrass. Ship Stability for Masters and Mates. Oxford: Butterworth-Heinemann, 2006. Print. Engineering Toolbox. N.p., n.d. Web. 7 Nov. 2013. <http://www.engineeringtoolbox.com/>. Riley, William, Leroy Sturges, and Don Morris. Mechanics of Materials. 6th ed. N.p.: Wiley, n.d. Print. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 56 Appendix A: EES Calculations "Volume of box" L_box=8 [ft] * convert(ft, m) {H_box=(4/12) [ft] * convert(ft, m)} H=H_box*convert(m, in) W_box=5 [ft] * convert(ft, m) Vol_box=L_box*H_box*W_box "Volume sides" W_bottom= 52 [in] * convert(in, m) Vol_sides=(0.5*L_side*H_side*L_box)*2 L_side=(W_box-W_bottom)/2 H_side=H_box "Volume of curve" W_curve=W_box A_curve=2 [ft] * convert(ft, m) B_curve=H_box Vol_curve=pi*A_curve*B_curve*W_curve "Total volume" Vol_tot=Vol_box+Vol_curve-Vol_sides Vol_tot_ft=Vol_tot*convert(m^3, ft^3) "Density of water" T=298 [K] P=101.325 [kPa] rho_water=density(steam, T=T, P=P) "Weight of fluid displaced" m_dis=Vol_tot*rho_water F_dis=m_dis*g g=9.81 [m/s^2] F_water=F_dis*convert(N, lbf) {F_water=1500 [lbf]} "Trolling Motor" lb_Thrust_needed = (F_water/200)*5 every 200 lbs weight" "General Rule of thumb being 5 lbs thrust for "Shaft Selection" "Assume 22inch high boat" H_boat = 22 [in] Waterline_height = H_boat - H This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 57 "!Stability - angle of list" "Boat Weights" W_side=90 [lbf] W_bottom=250 [lbf] W_motor=60 [lbf] W_front=140 [lbf] W_man=200 [lbf] W_floor=100 [lbf] "Heights of mass centers" y_side=11 [in] y_bottom=0 [in] y_motor=22 [in] y_front=23 [in] y_man=44.32 [in] y_floor=4 [in] "Horizontal distances of mass centers" x_width=60 [in] x_side_1=0 [in] x_side_2=x_width x_bottom=x_width/2 x_motor=x_width/2 x_front=x_width/2 x_man=x_width/2 x_floor=x_width/2 "Center of gravity" Sum_weight=W_side*2+W_bottom+W_motor+W_front+W_man+W_floor x_bar=(W_side*x_side_1+W_side*x_side_2+W_bottom*x_bottom+W_motor*x_motor+W_front*x_front+W _man*x_man+W_floor*x_floor)/Sum_weight y_bar=(W_side*y_side*2+W_bottom*y_bottom+W_motor*y_motor+W_front*y_front+W_man*y_man+W_fl oor*y_floor)/Sum_weight "Stability parameters" BM=(L*(B^3))/(12*V) V=L*B*Draft L=96 [in] B=x_width Draft=4 [in] KB=(1/2)*Draft GM=BM-BG BG=KG-KB y_bar=KG "Angle of list" GG_1=(W_man*d_shift)/Sum_weight d_shift=x_width/2 tan(theta)=GG_1/GM "Distance tip" Tip=tan(theta)*x_width/2 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 58 Appendix B: Design Drawings Preliminary Design Drawing Figure 30: Preliminary design drawing. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 59 Current Design Drawings Using the design process shown above, the following design drawings were developed. Figure 31: Side view, top down. Figure 32: Side view, top up This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 60 Figure 33: Front View Figure 34: Top View This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 61 Figure 35: Boat removed from trailer. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 62 Figure 36: Colored side view, top down. Figure 37: Colored side view, top up. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 63 Figure 38: Colored perspective view showing entrance. This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. 64 Appendix C: Budget Table 11: Complete Project Budget Component Boat 5052 Aluminum 0.160" thick, 2 sheets 48" by 96", 2 sheets 60" by 144" Boat Forming and Welding Cutting of Aluminum Tie down points for trailer, 2 rear and 1 front Bending of soft top mounting rails Windows, 1/4" plexiglass Window gasket material 1997-2006 Jeep TJ/LJ Windshield, top gasket, hinges, and bolts Indoor/outdoor carpet Boat Plug Light Khaki Metallic Paint, 2 quarts Door piano hinge, 21" long Door latch Door gasket Wood flooring - 3/4" plywood, 4'x8', 3 sheets, exterior BC grade Misc Hardware - screws for floor, shock mount bolts, motor mount bolts, etc. Door aluminum, 0.125" thick, 36" by 48", 3003 grade Door cutting Windshield steel Aluminum angle for floor support, 2"x2" by 0.125" thick, 24 ft Epoxy primer Motor Mount Motor Tubing - 1.5", 1/8" wall, 15 ft Bushings - 4 shackle bushings for Jeep CJ7 DOM for bushings, 1.5", 1/4" wall, 8" Aluminum attachment brackets Steel plate for mount, 0.125" thick Board for motor mount Top Canvas material, LJ soft top Source Cost Schupan Premier Metal Preferred Machine Calvin Metal Shop Quality Sheet Metal Menards Mcmaster Pete's Auto Parts/Craigslist Menards Gemmens Wyrick Company Machine shop Ebay Hiemstra Menards $653.92 $1,900.00 $183.00 $0.00 $5.00 $60.00 $28.00 $150.00 $25.82 $4.23 $55.00 $0.00 $20.00 $0.00 $101.00 Menards $36.81 Calvin Metal Shop Preferred Machine Quality Sheet Metal Calvin Metal Shop $0.00 $22.00 $52.00 Eastwood $0.00 $0.00 Mast Calvin Metal Shop $0.00 $0.00 Hiemstra Calvin Metal Shop Calvin Metal Shop Calvin Metal Shop Menards Craigslist This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. $0.00 $0.00 $0.00 $0.00 $0.00 $50.00 65 Jeep LJ soft top canvas, windows, and hardware Aquaview 40 ga, dark smoke tint vinyl Soft top mounts - 2"x2"x1/8", 8ft aluminum tubing Soft top mount - 1.75"x1.75"x1/8", 35.4 inches aluminum tubing Soft top alteration Canvas parts - buttons, velcro, zippers, thread, etc. Aluminum strips for zippers on windshield Trailer Raw Materials, 4"x2" and 3"x2", 0.125" wall Axle Tie down points - eye bolts Paint - black Airbag Suspension Mounting Bars/Brackets for arms U-Bolts Ratchet Straps Cable Ties Grip Tape Misc Nuts/Bolts Monroe shocks Shock mounts Bump stops Arm bushings Arm bolts Wheel adapters 35" tires and aluminum wheels Shock mount laser cuts for axle UHMW strips Trailer fenders Airbag mounts Push-In Grommets Fender lock washers Fender wide washers Fender bolts Winch Air fittings Air line Regulator 2"x2", 0.25" wall steel tubing for arms, 13ft Craigslist Canvas Innovations Calvin Metal Shop Schupan Nel Osterwald Nel Osterwald Calvin Metal Shop Progressive Surface Holland Trailer Progressive Surface Tractor Supply Airlift Company Premier Metal AB Spring Service Gemmens Gemmens Gemmens Gemmens Cascade 4wd Cascade 4wd Cascade 4wd Cascade 4wd Cascade 4wd Craigslist Hiemstra Premier Metal Progressive Surface Premier Metal Premier Metal McMaster McMaster McMaster McMaster Harbor Freight Calvin Metal Shop/Innotec Innotec Calvin Metal Shop Premier Metal This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent. $230.00 $144.11 $0.00 $25.72 $0.00 $64.87 $0.00 $175.00 $102.00 $0.00 $50.00 $0.00 $0.00 $11.83 $18.01 $2.53 $13.77 $0.69 $20.00 $5.00 $17.00 $40.00 $6.00 $30.00 $0.00 $0.00 $0.00 $0.00 $0.00 $8.08 $5.21 $6.66 $9.73 $30.73 $0.00 $0.00 $0.00 $0.00 66 DOM tubing for arm bushings, 2", 0.25" wall Epoxy primer Winch mount plates, 2 3"x2", 0.125" wall steel tubing, 22" long 2"x2", 0.125" wall steel tubing, 12" long Premier Metal Eastwood Calvin Metal Shop Progressive Surface Calvin Metal Shop Hitch Premade hitch 2" OD, 1.5" ID square tubing 2.5" x .25" wall Steel Tubing 1"-8 x 6" grade 8 bolt Top Link Ball, Category 2 Sleeve 1"ID, 1.25" OD Category 3 to 2 Top Link Bushing .75" ID/1" OD Bushing .75" OD, 5/8" ID Bushing 1" grade 8 bolt/nut/washers 1" ID, 1.25"OD Sleeve 1.25" shaft collar, 2" OD Hiemstra Calvin Metal Shop Calvin Metal Shop McMaster Tractor Supply Company Tractor Supply Company Tractor Supply Company Tractor Supply Company Tractor Supply Company Calvin Metal Shop Tractor Supply Company Tractor Supply Company Other Sand for blasting Menards Total $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $9.76 $8.99 $2.99 $8.97 $2.29 $1.99 $0.00 $2.99 $4.99 $24.00 $4,430.69 This document is the property of Team 14: Expedition Camper (Calvin College). Duplication of any portion of this document may only be done with team consent.