Velo-Final_09-10.pdf

Oregon Institute of Technology Mechanical and Manufacturing Engineering and Technology Department

Team ECO-Fast: Velom elomobil obile e Green Commuting Designed for the Real World 

June 3, 2010

Team Members:  Shawn Miller  David McDowell  Brian Ziegler  Matt Phelan

Advisor: Dr. Hugh Currin, PE 

The following report covers the design, construction and testing of the 2009-2010 MMET Velomobile Sr. Project. This project was completed by four four undergraduate Mechanical Engineering students with assistance from two separate design teams.

Team ECO-Fast

Page 3 of 50

Final Report: June 3, 2010

T ABLE OF CONTENTS Table of Contents ............................................................................................................................ 3 Table of Figures .............................................................................................................................. 5 Abstract ........................................................................................................................................... 6 Introduction .............................................. .................................................................................................... ...................................................... ................................. 6 Background ..................................................................................................................................... 7 Evolution .............................................. .................................................................................................... ...................................................... ................................. 7 Current Adaptations ............................................... ...................................................................................................... ....................................................... .............. 8 The Aerorider SPORT ........................................................................................................ 8 The Alleweder ................................................ ....................................................................................................... ....................................................... .............. 9 The Go-One3 ...................................................................................................................... 9 The Cab Bike .................................................................................................................... 10 The Glide T1 ..................................................................................................................... 10 Design Criteria .............................................................................................................................. 11 Drive-train:.................................................... ...................................................... ...................... 11 Braking:..................................................................................................................................... 11 Suspension: ............................................................................................................................... 11 Cost: .......................................................................................................................................... 12 Power Assist: ............................................................................................................................ 12 Component Description ................................................................................................................ 12 Main Frame ................................................... ......................................................................................................... ...................................................... ...................... 12 Design Requirements ........................................................ ................................................ 12 Frame Design ................................................. ........................................................................................................ ....................................................... ............ 14 Results ................................................... ......................................................................................................... ...................................................... ...................... 16 Construction ................................................... .......................................................................................................... ....................................................... ............ 17 Analysis of Design ................................................... ....................................................................................................... .................................................... ..... 17 Front Suspension .................................................... ....................................................... ............ 18 Description ..................................................... ....................................................... ............ 18 Results ................................................... ......................................................................................................... ...................................................... ...................... 20 Analysis............................................................................................................................. 20 Construction ................................................... .......................................................................................................... ....................................................... ............ 21 Rear Suspension ..................................................... ....................................................... ............ 21 Description ..................................................... ....................................................... ............ 21 Research ................................................ ...................................................................................................... ...................................................... ...................... 21

Team ECO-Fast

Page 4 of 50

Final Report: June 3, 2010

Results ................................................... ......................................................................................................... ...................................................... ...................... 24 Analysis............................................................................................................................. 25 Interface ............................................................................................................................ 26 Steering ..................................................................................................................................... 27 Description ..................................................... ....................................................... ............ 27 Results ................................................... ......................................................................................................... ...................................................... ...................... 27 Research ................................................ ...................................................................................................... ...................................................... ...................... 28 Design ............................................................................................................................... 31 Stress Analysis ............................................... ...................................................................................................... ....................................................... ............ 31 Analysis............................................................................................................................. 32 Seat ................................................ .................................................................................................... .................................................... ........................................ 32 Description ..................................................... ....................................................... ............ 32 Results ................................................... ......................................................................................................... ...................................................... ...................... 33 Design ............................................................................................................................... 33 Construction ................................................... .......................................................................................................... ....................................................... ............ 34 Power Assist Connection .......................................................................................................... 34 Project Results .............................................................................................................................. 35 Overview of Results ............................................... ...................................................................................................... ....................................................... ............ 35 Criteria of project met ...................................................... ...................................................... ... 35 Project Management ..................................................................................................................... 35 Conclusions .............................................. .................................................................................................... ...................................................... ............................... 36 Obstacles ................................................................................................................................... 36 Successes................................................................................................................................... 37 References ................................................ ...................................................................................................... ...................................................... ............................... 39 Sponsors and Other Help .............................................................................................................. 41 Appendices ............................................... ..................................................................................................... ...................................................... ........................ 42-108 108

Team ECO-Fast

Page 5 of 50

Final Report: June 3, 2010

T ABLE OF FIGURES Figure 1: Aerorider SPORT ................................................ .................................................................................................... .................................................... ....... 8 Figure 2: Alleweder .................................................. ......................................................................................................... ....................................................... .............. 9 Figure 3: Go-One3 .......................................................................................................................... 9 Figure 4: Cab Bike .................................................... ....................................................... ............ 10 Figure 5: Glide T1 ..................................................... ....................................................... ............ 10 Figure 6: Frame Assembly .................................................. ...................................................................................................... .................................................... ..... 15 Figure 7: FEA Analysis Example ................................................ ................................................................................................ ................................................ 16 Figure 8: Applied Loads ..................................................... ...................................................... ... 17 Figure 9: Suspension Design 1 ..................................................................................................... 19 Figure 10: Suspension Design 2 ................................................................................................... 19 Figure 11: Possible Swing Arm Configurations ........................................................................... 23 Figure 12: CAD Model of Rear Suspension Swing Arm ............................................................. 24 Figure 13: Cutaway View of Rear Shock Sh ock Design ................................................... ......................................................................... ...................... 26 Figure 14: Ackerman Steering Geometry ...................................................... ............................... 29 Figure 15: Part Number Example ................................................................................................. 43

Team ECO-Fast

Page 6 of 50

Final Report: June 3, 2010

 ABSTRACT The following report covers one of the Manufacturing and Mechanical Engineering Technology (MMET) senior projects undertaken at Oregon Institute of Technolo gy Klamath Falls campus during the 2009-2010 academic year. The project consists of the design, construction, and analysis of a velomobile with electrical power assist, and integrated control system. The group undertaking the trike portion of this project, is team Eco-FAST: this group, consists of David McDowell, Shawn Miller, Matt Phelan, and Brian Ziegler. During the course of the 2009-2010 academic year, Team Eco-FAST designed and constructed the main trike chassis, along with testing of the completed trike. Matthew Ferdinand, a graduate student in the Manufacturing Engineering Technology masters at OIT will design and construct the fairing portion of the  project. The electric assist system will be designed and manufactured by a second MMET Senior  Projects team. A third team contracted for the design and construction of the integrated control system from the Computer Science and Engineering Technology (CSET) department at OIT constructed an integrated control system for the electric assist of the vehicle. Dr. Hugh Currin, PE, is the project manager for both of the MMET groups, while Professor Jim Long will be overseeing the CSET team.

INTRODUCTION A velomobile is generally defined as a human powered vehicle equipped with a partially or fully enclosed fairing. This fairing provides both improved aerodynamic properties and protection for  the user from fluctuating weather conditions. These vehicles allow for users to ride in allweather conditions with improved comfort over a recumbent trike, recumbent bicycle, or  standard bicycle. Velomobiles can also be adapted to allow for increased storage over that which is found in any other type of bicycle. This allows for a user to be able to commute daily, to and from work, with all their necessary supplies without relying upon an automobile. However, as more weight is added to the velomobile it may become difficult for a user to surmount simple obstacles, such as hills or steep driveways. For this reason, small motor assists can be incorporated into the design of the velomobile to assist a user in physically demanding situations. Overall, a velomobile is intended to supplement a user ’s need to depend on an automobile for  daily commuting to and from work, and around town. Throughout the 2009-2010 academic year team Eco-FAST designed, constructed, and produced the trike portion of the project, while

Team ECO-Fast

Page 7 of 50

Final Report: June 3, 2010

working closely with the other contracted teams to construct the additional components required to produce the velomobile. The following report covers Eco-FAST’s design, analysis and construction of the velomobile’s trike assembly along with a background of currently available designs and the history of the velomobile. The goal of this project is to create a proof of concept that can later be re-engineered into a full production project, producing between 20 and 100 velomobiles a year. This project will also be available to be re-engineered in later years to help reduce weight, and improve design components as seen fit by future Senior Project teams.

B ACKGROUND There are currently a variety of velomobiles on the market, produced by manufacturers all over  the world. The following section will look into some of the designs that are currently available to consumers, or have been in the past. The velomobile is not necessarily a new concept; however, Eco-FAST hopes to be able to add a new spin to this old idea by creating a more economical and user friendly velomobile, marketable to the general public at a more affordable  price than what is currently available.

Evolution Even though the velomobile is not commonly known among the general populous of the United States, these human powered vehicles are not a new development.

Designed to be an

alternative for all-season commuting, the velodrome (as the first of these t ypes of vehicles were called) was a fully enclosed vehicle that relied entirely on human power. During the 1930's, Charles Mochet developed what is essentially an enclosed tandem cycle, "The Velocar". The intention behind the design for the Velocar was to make a lightweight, safe, pedal-powered vehicle for the road. Mochet was also the founder and designer of the two wheeled recumbent  bicycle, called "The Velo-Velocar.” Just before the occupation of France by Nazi Germany, during the years 1940 to 1945, Mochet developed the final version of his velocar, “The Velocar  Model H.” The Velocar Model H, and many other similar models, became symbols of the occupation. At the time, it was the most sophisticated mode of transportation when fuel was scarce.

Team ECO-Fast

Page 8 of 50

Final Report: June 3, 2010

Around the same time as the French-designed Velocar, a Swedish design for "The Fantom" was  being sold as blueprints. During the early 1980's, Carl-Georg Rasmussen used those blueprints and built a redesigned version he called the Leitra. In 1983, the Denmark-based Leitra company  began commercially producing Leitras. These velomobiles were intended for use in diverse weather conditions, with the basic design still based on the Fantom. The Leitra was approved by the Danish authorities for general use after systematic tests in 1982, on the condition that the cyclist should have free access to give signals for turn and stop with an arm. Leitras are still in  production today.

In the 1970s the People Power Vehicle was introduced to the U.S. as "an entirely new concept in replacing wholesome riding.” Manufactured by EVI of Sterling Heights, Michigan, it sold for  less than $400. This vehicle had a side-by-side configuration with easily adjustable seats, and looked similar to a small row boat with three wheels (delta design: two wheels in the rear, one in the front). The pedals also worked like a modern pedal-powered paddle boat. This design, however, was not a true velomobile; it did not give proper weather protection and was not efficient on the road.

Current Adaptations Today there are many velomobile manufacturers around the world, however few successful companies reside within the United States. Some of the current models available today are detailed below: The Aerorider SPORT 

Manufactured by: ........................... Aerorider  Type: ....................................... Open Cockpit Wheelbase: ........................ 54.3 in / 1340mm Track: .................................. 32.7 in / 830mm Overall Length: ............... 109.5 in / 2780mm Weight:......................Approx 55 kg / 121 lbs Cost: ...................... Approx. $11,280 / €7600 http://www.aerorider.com/ Figure 1: Aerorider SPORT

Team ECO-Fast

Page 9 of 50

Final Report: June 3, 2010

The Aerorider SPORT is manufactured by Aerorider out of the Netherlands. While the weight and price of the velomobile are above average, these characteristics are a direct cause of the electric assist that comes standard on the Aerorider SPORT.

The Alleweder  Manufactured by: ..... Velomobile USA, LLC

Type: ....................................... Open Cockpit Wheelbase: .............................................. N/A Track: .................................. 30.0 in / 762mm Overall Length: ............... 101.8 in / 2586mm Weight:.....................Approx 31.8 kg / 70 lbs Cost: ........................ Approx. $5,595 / €3769 http://pedalyourselfhealthy.org/

Figure 2: Alleweder

The Flevobike Alleweder was originally designed and produced by the Dutch company Flevobike. It is now be produced in the U.S. by the company Velomobile USA, LLC out of  Midland Texas. The Alleweder is a relatively simple package for a velomobile and is a result of  ten years of refinement from Flevobike. Kits are also available at a cost of approx. $3,395 /  €2293. The Go-One3

Manufactured by: ............................... Beyess Type: ..................................... Closed Cockpit Wheelbase: ........................ 53.2 in / 1350mm Track:................................... 28.4 in / 720mm Overall Length:................ 104.3 in / 2650mm Weight: ....................... Approx 30 kg / 66 lbs Cost:.................... Approx. $7,811.98 / €5263 Figure 3: Go-One

http://www.go-one.us/index.html

The Go-One3 is a fully enclosed velomobile manufactured by Beyess out of Germany. It is distributed in the U.S. and Canada through Undercover Cycling aka Go-One LLC based in Maywood, New Jersey. It should be noted that the $7,811.98 / €5263 is the starting price, adding

Team ECO-Fast

Page 10 of 50

Final Report: June 3, 2010

options and upgrades from the dealer can put the price in excess of $16,000 / €10800. The GoOne3 is an example of a premium velomobile package: lightweight and fully enclosed.

The Cab Bike Manufactured by: .................Cab Bike Gmbh

Type: ..................................... Closed Cockpit Wheelbase: .............................................. N/A Track: .................................. 29.5 in / 749mm Overall Length: ................. 94.5 in / 2400mm Weight:........................Approx 32 kg / 71 lbs Cost: ........................ Approx. $6,856 / €4619 Figure 4: Cab Bike

http://www.cab-bike.com/english/

The Cab Bike is designed and manufactured in Germany and has the capability of being either  open or closed type cockpit. There are various attachments that can be added or removed to the  base fairing to create either a closed cockpit, a speedster fairing, or somewhere in the middle. It should be noted that the $6,856 / €4619 is the starting price for the Cab Bike with higher end models coming in at $8974 / €6046. The Glide T1

Manufactured by: ....................... Greenspeed Type: ........................................ Open Cockpit Wheelbase: ........................ 50.0 in / 1270mm Track:................................... 29.9 in / 760mm Overall Length:................ 106.3 in / 2700mm Weight: ....................... Approx 30 kg / 65 lbs Cost:.......................... Approx. $8990 / €6056 Figure 5: Glide T1

http://www.greenspeed.com.au/Glyde.htm

Manufactured by Greenspeed, an Australian based company, the Glide T1 is the latest in a line of  velomobiles provided by this company that specializes in trike design. The Glide T1 is a light, agile, open cockpit velomobile with a full suspension.

Team ECO-Fast

Page 11 of 50

Final Report: June 3, 2010

These five currently available designs all demonstrate positive attributes to the ideal velomobile. However, each also has aspects that can be improved upon. The goal of this project was to attempt to create a proof-of-concept, incorporating practical design and engineering to create a cost effective production vehicle.

DESIGN CRITERIA The following section gives an overview of the criteria of the project. Further details of the original criteria of this project can be found in the proposal generated by team Eco-Fast December 2009. Some details of the original criteria outlined in the proposal have been reconsidered and/or negated during the course of the project and in turn are absent or modified in the final design.

Drive-train: A wide range of gearing is necessary to allow the rider to propel the fully loaded velomobile over any grade allowed by the Department of Transportation for public highways. Currently the maximum allowable grade is 10%. Analysis of appropriate ranges of gear inches found that a range of 22 to 80 inches will provide the needed gearing. This range of gear inches would allow the rider to climb any allowable grade, while still maintaining the ability to cruise under power at speeds below 30mph.

Braking: Per Oregon law 815.282 part (a): “A bicycle must be equipped with a brake that enables the operator to make the braked wheels skid on dry, level, clean pavement.” This, or a close approximation of this, is universal for all 50 states and can be attained with the current design of  the trike.

Suspension: To increase the overall comfort of the rider, as well as increase market appeal, a full suspension of all wheels is necessary. With daily commuting considered to be the main terrain this vehicle with be used for, large and aggressive suspension travel will not be needed. The suspension system will serve to isolate the rider from vibration and jarring due to road surface conditions,  potholes and other hazards, and driveway “lips”. At most a 2inch high, perfectly square step-up or step-down.

Team ECO-Fast

Page 12 of 50

Final Report: June 3, 2010

Cost: The production cost of the velomobile should be as affordable as possible. Currently velomobiles run from $2,500 for a kit to over $14,000 for a high-end, assembled unit with power  assist. A retail cost of approximately $6,000 should be reasonable for this type of vehicle. Production cost should be between approximately $2,000 and $2,500. After a company has been established (the first few years are almost never profitable) a production capacity of between 100 and 300 units per year is anticipated. Initial calculations lead us to believe that a profitable company could exist by manufacturing and selling 200 units per year, with approximately 75  percent of the units being sold at wholesale cost to distributers.

Power Assist: A bolt-on electric power-assist system was required in the design of this project. This power  assist should not be capable of propelling the vehicle, unassisted by the rider, at a speed of not more than 30mph on level pavement (per Oregon law 801.345). This feature can greatly enhance the enjoyment of long commutes or hilly terrain, as well as increase market appeal.

COMPONENT DESCRIPTION The following section covers the five main segments of design needed in the creation of this  project. A detailed description of the Main Frame, Front Suspension, Rear Suspension, Steering, and Seat design are included in the following sections. Each section will discuss the design, research, analysis and final construction of each portion as it pertains to the project. Additional information on these sections can also be found in the appendix section of the report for detailed drawings and stress analysis calculations.

Main Frame The following section covers the developments of the Main Frame of the project. This portion of  the velomobile is essentially the back bone for which all other components attach to or rely on for strength and stability in the constructed design. Design Requirements In designing the frame a number of constraints had to be considered. The frame required the

ability to support the weight of a rider, a full fairing, an electric assist unit, components,

Team ECO-Fast

Page 13 of 50

Final Report: June 3, 2010

optional luggage and withstand the rigors of daily commuting. Aside from the applied forces, the frame required the allowance of varying human dimensions. After researching designs present on the market today, it was decided that the main frame would be modeled with adaptations from the Greenspeed GTR 20/20 touring trike. With a set of Greenspeed trike plans, purchased from Greenspeed of Australia, a reference is available for both strength and human dimensions proven, in real world application. The loading requirements for the frame vary greatly depending on the rider and daily application of the velomobile. The typical loads applied to the frame are the rider, fairing,  power assist unit, and luggage. For design purposes a range of loading possibilities was determined for each. A typical rider should be between 120 and 300 lbs, the fairing should  be between 50 and 70 lbs., power assist unit 10 to 15 lbs., and luggage 0 to 100 lbs. All of  the loads listed above are applied vertically and downward on the frame. While there is no  problem if the minimum loads are not reached in the design, the maximum loads may cause issues. Designing for a maximum load of a 300 lb rider accommodates all members of the team. Luggage loading typically will be around 50 to 60 lbs of weight based on typical trips made  by members of the team; a 60 lb backpack of textbooks and other equipment is not out of  the question for a daily commuter. With touring the loads should increase over daily commuting, therefore the design load was determined to be 100 lbs. The electric assist unit was required to be 15 lbs. or under based on the preliminary designs from the power assist team and constraints set by team ECO-Fast. The fairing estimates were based on a desired distribution of loading. The fairing loading depends largely on the final design and material selected, therefore this is purely an estimate for design purposes and the actual weight could vary greatly but will be under the estimated weight of 75 lbs. It was decided that the frame would be designed to meet the worst case scenario loading. Regardless of the application chosen for the velomobile, be it commuting, touring, or rider  weight the frame can withstand all of the possible combinations. The worst case scenario loads used in calculation are listed in Table 1.

Team ECO-Fast

Page 14 of 50

Final Report: June 3, 2010

Table 1: Maximum Main Frame Loading

Type of Load

Load for Design

Rider

300 lbs.

Luggage

100 lbs.

Electric Assist Unit

15 lbs.

Fairing

75 lbs.

Total Vertical Loading

490 lbs.

Of the loads listed most of the loads are point loads (the rider), and others are to be distributed, (luggage, fairing, and other components). The rider load weight will be distributed throughout the seat of the trike and sent to the four seat mounts. While an actual distributed load of the rider FEA analysis of the frame would yield results closer to the actual stresses, the use of bolts and welds to attach parts and components to the frame cause loads to act on the frame in a manner similar to that of point loads. The frame was designed in such a way that a wheel will fail prior to the frame failing. A good estimate of wheel failure is 1000 lbs.1 of vertical load (Straight down from the hub at the center of the wheel); therefore the frame was designed to handle a 1000 lbs. load at each of the mounting location for the wheel. The force generated by a rider when pedaling was also taken into account as significant moments can be generated by this loading. The estimate of 500 lbs. of max pedaling force was applied to the FEA analysis. Frame Design Based on the constraints listed, three possible materials were chosen as c andidates for the

frame: Aluminum, Mild Steel, and 4130 “Chromoly” Steel. Carbon Fiber would also be a  possibility in future iterations, for a proof of concept a carbon fiber frame would be too costly and time consuming. Aluminum would be an excellent choice for saving weight, but it is inherently the most difficult metal option to weld too and would require heat treating to achieve the desired strength characteristics. At the time of design the cost of aluminum was also very high. Mild Steel would produce the heaviest frame, but the least costly. While strength characteristics and workability were desirable, welding on the frame would require heat treating to achieve the desired strength. Looking at the three options available chromoly 1

"Ian's Bicycle Wheel Analysis - Rim Strength."  – Note the source calculates 4551 N which approximates to 1023 lbs

Team ECO-Fast

Page 15 of 50

Final Report: June 3, 2010

steel was selected. Chromoly steel has the best strength characteristics allowing for a lighter  design than mild steel (a thinner wall can be used on the tubing to achieve the same strength. While not as light as aluminum, it is easy to weld and does not need to be heat treated. Machining is more difficult to accomplish with chromoly steel than either mild steel or  aluminum, but not impractical. Thus the chosen material for the frame was set to 4130 chromoly steel. Designing the frame with the above loads in mind, a single chromoly tube will be used for  the main body of the frame. The tube was originally designed to be bent instead of cutting, mitering, and welding pieces together. It was discovered that thin wall chromoly tubing is very difficult to bend and the proper die to achieve the bends within a reasonable time frame could not be located. The tube was cut and mitered to meet the desired angles and overall shape (See Figure 6).

Figure 6: Frame Assembly

The entirety of the frame was designed/modeled in SolidWorks® prior to strength analysis. The design testing for the frame was completed using both hand calculations and FEA software, specifically Pro Engineer ® as SolidWorks® did not have the capabilities to perform FEA at the time of design.

Team ECO-Fast

Page 16 of 50

Final Report: June 3, 2010

Results With the tensile strength of chromoly steel being 81,200 psi 2 the factor of safety for a variety

of tubing sizes and loads was calculated using the FEA package from Pro Engineer (See Figure 7).

Figure 7: FEA Analysis Example

The FEA analysis produced a worst case scenario factor of safety of 2.55 using wheel failure loads. Therefore the frame should withstand well over twice the force required to cause a wheel failure. For maximum expected loads on the frame (see Figure 8) and a pedaling force of 500 lbs (applied at the very tip of the main tube and the theoretical seat mounting  point in the rear), the factor of safety came out to be 7.6. Referencing Figure 7, the area in red is subjected to approx. 10,700 psi of stress. Although under the normal maximum riding conditions no failure should occur this area is of interest for both long term fatigue and failure. Although not shown in Figure 7, the connection point between the side tubes and the main tube in the frame was an area of interest as well for the wheel failure analysis. Again, no failure should occur under any normal maximum riding conditions, but it is important to keep the areas subjected to the most stress in mind during the design of the frame.

2

Matweb- http://www.matweb.com/search/DataSheet.aspx?MatGUID=f552d649b03e464f96ccdd976 0978ee0

Team ECO-Fast 15 lbs.

100 lbs.

Page 17 of 50

Final Report: June 3, 2010

15 lbs. 500 lbs. 15 lbs. 15 lbs. x 2

500 lbs.

300 lbs. 15 lbs.

Figure 8: Applied Loads

Construction After generating a full set of working drawings from the SolidWorks® models created

construction on the main frame began. Construction was fairly simple and straight forward  process. All tubes were initially cut to length incorporating mitered cuts where necessary. The tubing notches for the side tubes supporting the front suspension and the cutouts for the rear bottom bracket and swing arm pivot were more time consuming. Notches and cutouts were completed using a bimetal hole saw of the appropriate diameter, a generous amount of  cutting oil, and a slow feed rate. The only error encountered in the assembly was a miscalculation in the length of the side tubes. Since they were too long a simple cut back  remedied the error. Aside from that error, no pieces had to be re-cut and none of the extra material ordered needed to be used.  Analysis of Design The safety factor of 7.6 may seem excessive, and for the vertical load requirements it is.

Since this frame is dynamically loaded, the factor of safety is overshot to 6 to verify that it will handle the stresses the velomobile will be subjected to. For example, when a rider  approaching the maximum weight designed for rides over a curb a significant shock is  produced; it is necessary that no failures occur under this situation. The reason for the not designing the frame to make it lighter are based on weldablity and stiffness. The wall thickness chosen, 0.065 in, is fairly thin for welding. The teams welding capabilities were somewhat limited and it was thought that dropping to a 0.049 in wall thickness would cause added difficulty. The diameter could have been reduced to a 1.5 in

Team ECO-Fast

Page 18 of 50

Final Report: June 3, 2010

diameter (perhaps lower) in terms of strength, however stiffness was a concern, therefore 1.75 in diameter was selected. A larger diameter will ensure greater stiffness, although exact numbers were hard to figure. Cost was another factor: a 1.5 in diameter by 0.065 in wall was the cheapest to ensure strength, however 1.75 in diameter was desired; this combination was the second least expensive option. The final constructed frame performs well. The frame supports the required loads with minimal (if any) deflection aiding in a firm ride. All components attached to the frame with minimal issues. While not perfect, the desired outcome for the frame was achieved.

Front Suspension The main problem that had to be addressed in designing the front suspension of the Velomobile Senior Project for the Oregon Institute of Technology was to reduce the affects of bump steer on the steering of the vehicle. Bump steer is the term for the tendency of a wheel to steer as it moves upwards (Wikipedia). Bump steer is commonly caused by a change in the geometry between the steering arm and linkage as the wheel moves vertically. Along with designing the suspension to reduce the effect of bump steer the suspension also had to meet the requirements specified the in the design criteria which stated that the front suspension had to have a minimum of 1 inch of  wheel travel. Description With these two criteria to consider for the design two different front suspension designs

were created to reach the requirements. The first design shown in Figure 9, incorporated the use a urethane compression spring as the spring for the suspension. To reduce the effect of   bump steer the steering arm of the suspension is located so that it doesn’t move vertically with the wheel.

Team ECO-Fast

Page 19 of 50

Final Report: June 3, 2010

Figure 9: Suspension Design 1

The second suspension design shown in Figure 9 utilizes the use of two compression die springs instead of one large urethane spring. As in suspension design one, suspension design two utilizes a steering arm which is isolated from the vertical movement of the wheel.

Figure 10: Suspension Design 2

Team ECO-Fast

Page 20 of 50

Final Report: June 3, 2010

Results After analyzing the two different suspension designs, design 2 was chosen as the front

suspension design to use for the Velomobile. The main reason for this was due to the working restrictions of the urethane spring. The manufacturer’s restriction which limited the use of the urethane spring was the amount of allowable compression for the continuous use of the urethane spring. The manufacturer’s maximum suggested allowable compression was 15% of the total free length of the spring, so to have one inch of suspension travel a 6.66 inch urethane spring was needed. Which if used would make the front suspension to large and cumbersome. Since it was determined that the urethane shock wouldn’t be used, a pair of acceptable compression die springs needed to be found to meet the requirements. Due to the fact that reaction forces at the front wheels can change depending on the rider and fairing options  being used two different compression die springs were selected for the design one having a spring rate of 200 lbs/in and one having a spring rate of 288 lbs/in.  Analysis Since it was determined that the fir st suspension design won’t be used the next thing that

needed to be determined was the spring rate needed for the springs to be used. It was determined through an FEA analysis of the frame design done by Mat Phelan, show that the max static reaction force acting on ether of the front wheels was approximately 88 lbs. With the reaction force at the front suspension known the spring preload deflection could be determined in order to allow for minimum suspension compression when the rider gets of  the velomobile. The deflection which is needed to apply a preload of 45 lbs to each of the springs is 5/32” or 0.156”. With the force known at each spring location a spring rate could then be determined. To determine the spring rate needed it was decided that the suspension system should become fully ridged when there is it experiences somewhere between 3.5 and 5 g’s. When the spring rate was calculated it was found that the total spring rate of the fronts suspension should be between 315 lb\in and 450 lb\in. All hand calculations are contained in Appendix D. For the top piece of the spindle assembly a FEA analysis was done in Solid Works to determine the factor of safety of the piece when a wheel failure load is applied to the

Team ECO-Fast

Page 21 of 50

Final Report: June 3, 2010

suspension system. It was determined that the load required to induce failure of the wheel was around 1000 lbs. So a force of 500 lbs was applied to each spring location to determine the minimum factor of safety. The minimum factor of safety was found to be 4.4616. A screen shot of the FEA analysis is contained in Appendix II. Construction To complete the construction of the front suspension Jet Fabrication of Klamath Falls was

contracted to cut the profile of the bottom spindle. The reason for this was due to the complexity of the profile and the amount of time required to produce it using the machines available at OIT. All other machining and fabrication was done on OIT’s campus.

Rear Suspension The proposal requirements for this project state that the rear suspension of the vehicle must isolate the rider from road vibrations, as well as serve as a mounting point for the rear wheel. Through careful design and testing, a suspension system was designed that met all inherent and implied constraints for this vehicle. Description The rear suspension of the velomobile serves several purposes. First and foremost, the rear 

suspension must provide a mounting location for the rear wheel. Because the velomobile is rear-wheel drive, the mounting location for the rear wheel must also provide adequate clearance and mounting locations for the chain, derailleur, sprockets, and associated cables for these components. Finally, the rear suspension must provide sufficient rigidity to keep all components aligned during all loading and riding conditions the vehicle will encounter, as well as isolating the rider from unnecessary roadway vibrations. Research The design of the rear suspension system for the velomobile began with extensive research.

The designer began with a broad overview of velomobile and recumbent trike designs currently being produced in large quantities. These included: Ice Trikes recumbent tricycles Actionbent recumbent tricycles, Catrike recumbent tricycles, the Aerorider, the Alleweder, the Cab-Bike, the Go-One, and the Sunrider. All of these designs had some points in common: all were rear-wheel drive, all employ a “tadpole” configuration (two wheels in the front, one in the rear), and all are steered with the

Team ECO-Fast

Page 22 of 50

Final Report: June 3, 2010

front wheels. Upon closer inspection of the rear wheel and suspension on the aforementioned models, some differences were noticed. While all models did employ a single-pivot swing arm in conjunction with a linear spring-damper s ystem, the methods of  construction and the overall design varied significantly. The Go-One uses a very straight forward and simplistic approach of cantilevered square tubing with a small coil spring and concentric oil damper. This approach simplifies construction, simplifies static and dynamic analysis, and is relatively inexpensive in nature. On the other extreme, Ice Trikes uses a very complex truss design for the swing arm, along with a small elastomer puck placed just behind the pivot point. This design uses high quality aluminum alloys, extremely complex fabrication techniques, and requires Finite Element Analysis (FEA) to analyze loading due to the complex curves and gussets of the structure. This type of design is far beyond anything that could accurately be produced and tested given the time and resource constraints this project is bound by. The elastomer shock  acts similarly to a linear spring except it has a rather high, non-linear spring rate, combined with inherent self-damping properties. The use of an elastomer as a shock presents many  benefits: large resistance over small deflections, impervious to corrosion, requires no maintenance, lightweight, and low cost. Mounting these types of “springs” does prove somewhat challenging, and usually does not allow for any pre-fabricated spring or shock  absorber on the bicycle market to be swapped into the vehicle without extensive modifications. Once a better understanding of riding situations and suspension characteristics required for a  production velomobile were understood, the following list of criteria was generated: The rear suspension system must incorporate a single wheel, and this wheel will be the only point of contact for the rear half of the vehicle. The suspension system must provide a means of mounting the rear wheel, rear sprocket cassett assembly, rear derailer, and one end of the rear shock absorber. The rear suspension should have enough travel to allow the center of the rear axle approximately 1 inch of vertical deflection.

Team ECO-Fast

Page 23 of 50

Final Report: June 3, 2010

The rear suspension should incorporate a rather small, low maintenance shock absorber  to dampen the suspension’s cycling, and thus insulate the rider from road surface vibrations. If possible, the suspension system should be designed in such a way that a standard sized shock absorber, designed and produced primarily for mountain bikes and other such vehicles, could be used in the velomobile without requiring any modifications to the vehicle or shock absorber. Once this list of criteria was constructed, conceptual designs and rou gh ideas of possible suspension configurations were sketched by hand. After some initial refinement of sketches, along with additional research on existing models and communication amongst other  members of the team, the field was narrowed down to two possible designs, both consisting of a single pivot swing arm as shown below in Figure 11. The first consisted of a triangulated miniature truss, while the second employed a simple cantilevered beam.

Figure 11: Possible Swing Arm Configurations

All designs currently on the market employ one of these two configurations. The majority of  the designs, however, did employ a triangulated or truss configuration for the swing arm. While this configuration does have some benefits, a single cantilever beam provides comparable rigidity, takes up less space, and is far easier to fabricate and analyze. To further prove the superiority of a non-triangulated rear swing arm for the application, a

Team ECO-Fast

Page 24 of 50

Final Report: June 3, 2010

 preliminary estimate of strength to weight ratios was undertaken. See Appendix I for further  details. Results The final design used for the rear swing arm consisted of a non-triangulated, single-pivot

swing arm with a linear, polyurethane compression spring providing suspen sion travel and damping characteristics. A detailed drawing packet of this design may be found in Appendix II. The material used for this swing arm is 4130 rectangular chrome-moly tubing. This material was chosen for its strength and weld ability. For possible future designs, aluminum or carbon fiber could be used to further reduce the overall weight of the vehicle, however tooling for these methods of construction are far too expensive and time consuming for a “proof of concept” type vehicle. This suspension design provides extremely good strength and rigidity properties. For all testing encountered by the vehicle to date, the rear swingarm has not failed in any aspect. Even under non-standard conditions (to test out the ruggedness of the vehicle) the rear  swingarm has not permanently deformed or deflected in any area, and has provided useful mounting points for the embedded systems controller.

Figure 12: CAD Model of Rear Suspension Swing Arm

Team ECO-Fast

Page 25 of 50

Final Report: June 3, 2010

 Analysis Given the cantilevered configuration of the rear suspension, considerable stresses are

inherent in the member when the rear tire is dynamically loaded. While these forces are rather large, they are primarily in the vertical direction, as opp osed to the lateral loading encountered when the vehicle turns. For this reason, rectangular tubing was chosen for the swingarm due to its asymmetric strength properties. The tubing was aligned with the larger  axis in the vertical direction, thus offering the most strength vertically, while still maintaining considerable rigidity in the lateral direction. The shock absorber for the vehicle posed a rather intriguing problem. The project proposal stated that the rear suspension only deflect approximately 1” under maximum dynamic load. Given the geometry of the rear swingarm, this requires the shock to only compress approximately .375 inches. An estimated static wheel load of approximately 90lbs was calculated by Matthew Phelan. While this figure appears rather small, it can be changed drastically when additional luggage or components are mounted to the rear of the vehicle. Additionally, due to the large moment arm between the pivot point and the rear wheel mounting location, even small forces on the tire transform into rather large linear forces in the shock. This combination, large forces and small deflections, require a shock absorber  that is rather non-standard. The standard bicycle shock has a stroke ranging from 1.5” to 3”, along with having relatively low spring rates. For this reason, the shock absorber was designed to employ two relatively small elastomer compression springs, in a parallel configuration. This design allows for one of the elastomers (the primary one) to operate independently from the secondary elastomer under most conditions (no load to approximately 2.5 G of force). However, if a large impact is encountered, once the primary elastomer is deflected a pre-determined amount the second elastomer is acted on in a parallel fashion, thus increasing the spring constant of the system as a whole. A hand sketch of this design is shown on the next page (The original drawing may be found in Appendix III).

Team ECO-Fast

Page 26 of 50

Final Report: June 3, 2010

Figure 13: Cutaway View of Rear Shock Design

Interface The rear suspension interfaces with two other portions of the velomobile: the main frame

and the power assist unit. The power assist team was contacted during design to determine the location of the intermediate jack shaft within the main frame. Once the location and size of the track cogs of the jack shaft were determined, the rear suspension was designed to accommodate adequate chain clearances between the jack shaft and the rear hub. The interface between the main frame and the rear suspension proved to be rather simplistic in nature. Matthew Phelan, the frame designer, was contacted and the size and orientation of the rear portion of the main frame was established. Once these characteristics were known, it was relatively easy to design a method of mounting the rear swingarm to the main frame that did not provide any interference during suspension cycling. Once the swingarm

Team ECO-Fast

Page 27 of 50

Final Report: June 3, 2010

mounting location was established, CAD modeling packages were used to determine the approximate length of shock absorber that could be incorporated into the system.

Steering The following section discusses the necessary research, design and constructions that was undertaken during the course of this project to create an appropriate steering setup. As described in the criteria section above, the steering portion of the velomobile is required to allow the vehicle to turn within a standard rural road width without jeopardizing the stability or safety of  the rider or the vehicle. Through careful research and design this goal has been achieved for the  project. Considerations were also made to improve the ergonomics of the controls and rider  interface to reduce the chance of fatigue during daily commuting or long trips. Description As a part of the projects practical design it is necessary to research, design, and construct a

realistic and functional steering assembly that would meet the proposed requirements of the  project. The initial research conducted determined that the best solution to the expected steering requirements of the velomobile would be to design a linkage steering system similar  to the Greenspeed® GTR 20/20 layout. Design of this steering assembly has been modified over the course of the project as relations between steering and other components of the velomobile have continued to adapt as needed. Final design of the steering was completed in late March and construction began in late April. Final completion of all steering components and incorporation with the velomobile was completed mid May following the completion of the front suspension and seat construction. Results Initial testing of the steering assembly was completed May 30th, 2010 during the initial

testing of the velomobile. Throughout latter testing the steering system it was found that the velomobile was allowed to turn within a nineteen foot diameter turning radius without  jeopardizing rider safety or stability, thus meeting the criteria set for this project. With this turning radius the velomobile has the ability to safely turn within the width of a two lane rural or urban road. Larger radius turns are also able to be easily executed at a variety of  speeds without jeopardizing the safety and security of the rider. Through testing it was found that safe tight turns, 19 to 25 foot diameter turns, could be executed when speeds were

Team ECO-Fast

Page 28 of 50

Final Report: June 3, 2010

 below about 8mph. This speed issue was predominantly set due to the level of tire grab experienced by the outside tire during tight turns. In wider turning situations a rider was generally comfortable to navigate turns at or above a 25 foot diameter at speeds up to 15mph with little to no issues. At speeds between 15 and 25 mph it was found that slight maneuvers, such as driving down a winding bike path or navigating a twisting road, could easily be done without any safety issues for the rider. The only situations in which steering stability started to come into question were when the rider exceeded speeds of 30mph. At these speeds it is advised that the rider keeps the steering straight, with only very minor  adjustments. If major turns are needed at speeds above 30mph it was found that braking would be needed to bring the velomobile into a more appropriate speed to approach the turn. Final results found the steering system for this vehicle to be adequate and capable to navigate a rider through almost any turning situation that may be encountered on a rural or  urban road setting. It may also be noted that during testing all components of the steering system preformed without any issues and required no additional tooling or modification. Research In determining an appropriate steering setup it was found that a linkage steering system

incorporating an Ackerman design would provide the greatest benefit and control for the steering needs of the velomobile. From the research completed it was found that this setup is currently the most prevalent design used in trike and velomobile steering with a wide variety of adaptations. Essentially, the purpose of this design is to allow the vehicle to navigate smooth, safe turns at any reasonable speed, while minimizing or removing the chance of scrubbing the tires while navigating tight turns. Bump steering, the forcing of a tire due to hitting an uneven bump or obstacle, was also considered as a requirement that needed to be minimized for best comfort and safety of the rider. Through proper setups it is  possible to drastically reduce the occurrence of bump steer felt by the rider. Both of these issues were taken into account in the steering design for improved comfort and handling of  the velomobile and will be explained further in the coming sections.  Ackerman Steering Geometry The purpose of incorporating an Ackerman steering d esign into the steering geometry of 

the project was to minimize the effects of tire scrubbing while the vehicle was navigating

Team ECO-Fast

Page 29 of 50

Final Report: June 3, 2010

tight turns. Tire scrubbing is caused when both steering tires turn at the same angle relative to the centerline of the vehicle body. In tight turning situations, roughly over an 18 degree turn depending on application, the outside tire of a vehicle may slip on the surface of the road and slide away from the vehicles projected path of travel. This can cause excessive tire wear along with losses in efficiencies and t raction while navigating a tight turn. To counter the effects of tire scrubbing the use of Ackerman geometry is used through creating what is referred to as an Ackerman angle between the front control arms and the center of the rear wheel. To create this angle, the front control arms of the vehicle need to be pointed to the center of the rear wheel, in the case of a three wheel trike. This will create a triangle between the front control arms, front wheel axles, and the center of the rear wheel. With the control arms in this configuration the turning of the front wheels will be altered to different angles during a turn. Now instead of both tires turning with the same general angle, the inside tire will turn at a tighter angle than that of  the outside wheel. Also, if done correctly both of the front wheels will pivot about a similar point along the axis of the rear wheel. Both of these considerations are represented in Figure 14: Ackerman Steering Geometry Figure 14 below.

Figure 14: Ackerman Steering Geometry

As stated before, this setup should assist in minimizing the tire scrubbing effects felt by the vehicle and rider during the execution of tight turns. It is important to also note that Ackerman steering geometry is generally used as a reference only and even the best designs should still be considered as approximations. To properly refine the final steering design it is generally suggested that a trial and error process is used for final fine

Team ECO-Fast

Page 30 of 50

Final Report: June 3, 2010

tuning. In either case, the steering geometry found through the use of the Ackerman setup should allow for better turning than with a standard straight bar system. Bump Steering Consideration During initial research it became evident that bump steer consideration wo uld need to be

accounted for in the velomobile design to ensure the safety of the rider. Bump steering, as explained previously, is the forcing of a tire due to hitting an uneven bump or obstacle causing the front wheels pivot or veer off course. This can cause a variety of issues and safety hazards for the rider, and in turn must be minimized in the overall design of the trike. To counter this issue two different approaches were determined that should minimize or  completely remove the effects of bump steering. Through the consideration of other trike designs and other steering research it was found that modifying the “caster angle” could assist in reducing bump steering effects. The caster angle refers to the orientation of the king pin with the vertical axis of the wheel hub, similar to how a caster aligns with the king pin assembly on a shopping cart. If the wheel is designed to have a caster angle of  zero the king pin assembly should be completely vertical with respect to the ground. To apply a caster angle, the king pin assembly will be offset by an angle of five to ten degrees from vertical, about the center of the wheel hub. The second approach found looks at applying a camber angle to offset the effects of bump steer. The camber angel refers to the angle at which the front tires are pitched inward to align the centerline of the king pin with the contact point of each respective tire. For this  project a 14.5 degree angle was decided upon to provide the required camber angle that would be most beneficial. This change should align the forces experience by the tire with the axis of the king pin and reduce the effects of bump steering felt by the rider. If too great of an angle is applied to the front tires it may result in instability of the ride and excessive tire wear. With both of these considerations found to reduce the chance of bump steer it was necessary to incorporate them into the design of the velomobile. To accomplish this discussions were had to incorporate the appropriate caster and camber angle into the

Team ECO-Fast

Page 31 of 50

Final Report: June 3, 2010

components of the front suspension, as modification of steering components wou ld not affect the bump steering felt by the rider. Tracking Considerations As with all vehicles it is important that the velomobile travels in a straight path when

riding on a smooth flat surface. A rider should not have to constantly adjust the steering controls as they travel down the road to ensure that the trike follows a straight path. To ensure this result in the final design, tracking considerations were taken into account. After some research it was found that a slight “toe-in” to the front tires would result in  better tracking for the vehicle. This will involve creating a slight four to five degree angle to both front wheels resulting in the front of both front tires being closer to each other than the back. This small change should help to improve the handling of the velomobile and allow it to travel in a straighter line. Down sides can also arise in this change. If the front wheels angles are changed to too high of a degree it will cause excess wear on the tire, and excess resistance for the rider to overcome. For this reason it is best to start with a very small toe-in angle and in later increase the angle if desired. This modification to the steering can simply be adjusted by the front steering linkage and can be accomplished quickly during testing, or practical use of the velomobile. Design Steering design initially began with adapting the steering from the Greenspeed GTR 20/20

trike design. This design has continued to adapt as changes have been made in to the front suspension, main trike tube, and seat design. The current steering system use a linkage setup, with Ackerman geometry considerations with the front suspension, to obtain the desired steering results as decided upon by the group. A majority of the information gathered in the research of the steering design was incorporated to the front suspension of  the trike since most component alignment in the front suspension would affect the steering outcomes of the vehicle. Work was continued throughout the project with the front suspension to find the ideal setup for the velomobile design to both positively affect the front suspension and steering setups.  Stress Analysis Stress analysis has been conducted on the steering arms of the trike to ensure the current and

applied design will withstand the expected loads this vehicle will encounter. Initially the

Team ECO-Fast

Page 32 of 50

Final Report: June 3, 2010

steering arms were designed to withstand a vertical loading of 150 lbs applied to the top of  each handle bar. With this loading a safety factor of greater than two would be achieved with the given steering design. However, several weeks after ordering of materials was completed it was determined that the width of the seat would need to be increased to facilitate all members of the ECO-Fast team. This in turn required that the steering arms would need to be extended to meet the clearance needs between the inside of each steering arm and the outside of the seat tubing. With this change in the lengths of the steering arms the ability of the design to accept high loading on the end of each arm was greatly reduced from 150 lbs to roughly 60 lbs will retaining a with a factor of safety of 2. This issue was  brought to the attention of the front suspension and main frame portions of the project, and it was decided that a redesign would not be required to re attain the original loading abilities of  150lbs.  Analysis The initial requirements set for the steering needs of the velomobile by the Eco-Fast team

required that the vehicle be allowed to make a safe, controlled turn within the boundaries of  a standard two lane rural road or residential street. This required that the velomobile would need to be able to navigate a turning radius of 12 feet or less for standard two lane US road widths, with a preferred turning radius of nine-and-a-half feet. The current design and construction of the steering geometry provides the required turning rad ius without the fairing attached to the velomobile frame. During tight turning situations light to moderate tire scrubbing can be felt by the rider, but does not affect the safety of the vehicle unless the turn is approached at a higher than recommended speed. In all, the turning system designed for the velomobile has accomplished all that it was required to and allows for the vehicle to navigate turns as required without the fairing attached.

Seat  The following section covers the design related to the construction of the seat and selection of  the appropriate materials. Description As a part of the design of the overall trike it was necessary to design and construct an

appropriate seat to meet the demands and comforts of a variety of users. For this reason it

Team ECO-Fast

Page 33 of 50

Final Report: June 3, 2010

was determined that the seat required a necessary range of adjustment to allow for use  between several different sizes of riders. With this adjustment the seat still needed to be able to withstand the maximum loading as specified for the frame, along with withstand dynamic loading during standard use. Results Following the completion of construction on this section of the project a fully working,

adjustable, seat was constructed and mounted to the main frame of the trike. This seat meets all previously discussed requirements to work with a variety of users to provide a desired level of comfort and safety along with properly interfacing with all other aspects of the velomobile frame. Design The design of the seat for the trike was adapted for use from a non-adjustable Greenspeed

design. The Greenspeed seat was chosen due to its compact size and availability of detailed drawings and loading requirements. This provided a good starting point in the designing of  the final seat for the project. With the Greenspeed as a basis of design, adaptations were made to create an adjustable  back portion of the seat. This would allow riders the ability to adjust the seats recline for   both better visibility and comfort. To achieve this set up it was required that a pivot connection be constructed between the bottom portion of the seat and the seat backing. This  pivot was required to not interfere with the rider during normal use, but also provide the needed level of strength and stability to meet the loading requirements of the vehicle. Detailed drawings and an assembly of this pivot point and surrounding components can be found in the Appendix B of this document. Another important aspect of the seat design was determining the appropriate mounting needs for the seat to ensure that the seat does not collapse or deform under the weight of the rider. This was accomplished by creating four attachment points that would provide adequate stability for the seat without the addition of unneeded materials or weight. These mounting  points consisted of two fastened attachments, and two soft attachments.

Team ECO-Fast

Page 34 of 50

Final Report: June 3, 2010

The two fastened attachment points consisted of bolted sections that secured the seat tubing to the bottom and tail portions of the frame. These points provide the seat with the main stability required and take the major loading while the trike is in use. The two soft attachments were located on the front portion of the side tube of the main frame and consist of the seat ends resting on these rails during standard use. This provided an additional location for weight to be distributed throughout the frame, and reduce the chance for applied moments to be applied into the seat frame, resulting in a bending of the tubing. These attachment areas were considered to be soft attachments due to the fact that they were fastened in no way to the side tubes of the seat and the seat tubing rests on rubber bump stops to reduce vibrations. Construction Construction of the seat was conducted following the completion of the design. The entire

seat frame consists of thin-wall chromoly tubing. Once a design was finalized, CAD drawings of the individual pieces required for the seat were generated. Simple cutting,  bending, and notching operations rendered all required pieces ready for welding. The tubing was TIG welded together using a series of temporary jigs. Once the seat frame was constructed, a pattern for cutting the seat fabric was generated. The fabric was cut and the edges hemmed using a standard sewing machine. Once the fabric was hemmed, the grommet areas were reinforced with plastic backing material, grommet holes were cut, and grommets were installed with Gorilla Glue® to prevent pulling and fraying of the surrounding fabric. Once all components were constructed, the seat material was stretched over the frame and the grommets laced together with para-cord. After initial fitting and testing, the cord was retensioned and adjusted twice to accommodate fabric stretch and break-in.

Power Assist Connection During the design phase of the project a good deal of interfacing with the Power Assist team was required. An envelope of operation was developed and weight estimates were determined for the  purposes of FEA analysis. The position of the bottom bracket interface in the bottom tube of the main frame relies largely on the envelope requested by the Power Assist team. To optimize the weight and space the bottom tube was created as short as possible while still providing adequate

Team ECO-Fast

Page 35 of 50

Final Report: June 3, 2010

space for the gear box. The main support for the gear box was the jackshaft/bottom bracket assembly. A secondary bracket was created for support against rotation. Some of the design considerations taken into account in the placement of the gearbox were the position of the  jackshaft in relation to the rear swing arm pivot. Having the axis of both the jackshaft and pivot  provided optimal chain clearance as well as minimized chain length changes during shock  cycling. The latter is important to prevent chain slap and undesirable loading in the chain.

PROJECT RESULTS Overview of Results The overall result of the project was successful in the design and construction aspects of the trike, although there were a few problems that were encountered during the construction phase of  the project. One major problem encountered was locating a tubing bender large enough for the main frame tubing that was available within a reasonable time frame. Another problem encountered was reconciling interference issues with the rear swing arm and the chain.

Criteria of project met  In the construction of the velomobile all but one part of the criteria was met by the finished  product. The only part of the criteria which was not met was the construction of a fairing for the trike. This is not surprising since when creating the project proposal it was determined that the amount of time required to design and construct the trike could possible take up all the time needed for the construction of the fairing.

PROJECT M ANAGEMENT Upon review of the Gant chart that was created for the project proposal for the trike it was found that the team had set a much more optimistic and unrealistic time line then was actually followed. This was largely due to the amount of problems that were encountered in the design and fabrication process of the project. Another large contributor to the mismanagement of time was due to not having an official team leader to keep the team on track and constantly working. Upon completion of the trike and review of left over materials and supplies, it was determined that the amount and types of material need to complete the trike were very accurate and precise. Besides the initial order the only additional order needed was for a new size of delrin; this was

Team ECO-Fast

Page 36 of 50

Final Report: June 3, 2010

due to the delrin being used in more locations than originally thought and to prevent waste material in the machining processes.

CONCLUSIONS This project proved to be an incredible learning experience for all persons involved. From the initial research and design stages, through the material ordering process, and into the construction, fabrication, assembly, and testing of the vehicle, time and again the group was exposed to the true world of engineering. This project challenged the team members to work  together, both within their own team as well as interfacing their portions of the project with the other groups involved (Power Assist, and Embedded Systems). Additionally, the teams were exposed to the pitfalls and hazards inherent within a large project with a rather short deadline. While this project did encounter its share of setbacks, the overall outcome proved to be rather  impressive. Not only did all the teams complete their assigned projects within the given timeline, but the trike portion of the velomobile performs as specified in the project proposal. The following paragraphs provide a brief synopsis of the obstacles and successes the project encountered along the way, as well as the current status of the project and a summary of the vehicle testing to date.

Obstacles This project encountered three main obstacles during the course of the year: individual member  schedules, material ordering, and facilities/tooling conflicts. With such a large project (three individual groups with three to four members per group), one of the largest problems encountered was scheduling time when all members of the group could be present to discuss design discrepancies and proposals. Additionally, during construction the groups agreed that all machining and fabricating of components be carried out by at least two group members in order  to provide real-time error checking and quality control. Given that several members of the group were employed off campus for the duration of the project, combined with the fact that all members were taking heavy class loads, it became rather difficult for the members to meet for  more than a few hours each week. A particularly large setback encountered during the project was material ordering difficulties. Several members initially specified components for their designs that were found to be back 

Team ECO-Fast

Page 37 of 50

Final Report: June 3, 2010

ordered for several weeks at the time of ordering, or not available. While this may not seem incredibly cumbersome for a relatively drawn-out project, it did pose a problem since the group was already behind schedule once material ordering was undertaken. Secondly, the first batch of  steel that was ordered was sent in all 1ft. sections instead of 6 or 8 ft lengths as ordered. This added another 14 days for the incorrect material to be sent back, and the correct material to be received. Once materials were on site, another set of problems presented itself. The facility used for the fabrication and construction of the velomobile was the Senior Projects Lab of Cornett Hall at OIT’s Klamath Falls campus. This particular shop housed five different senior or junior projects. With twenty to thirty students constantly using both handheld and industrial tools, it became exceedingly difficult to locate, obtain, and keep specific tools required for component manufacturing. Additionally, some specialty tools were not available in the Senior Project Lab, thus team members would have to search around campus or move their work stations to different shops in order to complete their fabrication tasks. These several relatively small obstacles proved to be rather bothersome when compiled over the course of the project and lead to unintended and unforeseen delays.

Successes By far the successes outweigh the mistakes or problems encountered during this project. All groups finished their respective tasks within the time allotted, all components in terfaced correctly, and the trike performs as expected. By far the most impressive moment during the  project was the initial testing day. After all components are bolted together, most senior projects require quite a few trial runs that last only seconds. Usually, several modifications or changes are required before any sort of working prototype can be extensively tested. This was not the case with the velomobile. After a weekend of extremely long hours of fabrication, the team assembled all components of the vehicle for the first time on a Saturday afternoon. Once the final bolt was tightened, the vehicle was set on the ground to perform initial testing. The assembled trike worked as desired immediately following assembly, few if an y adjustments were required. An hour later, all members of the team had tested the vehicle under all typical (and several non-typical) situations.

Team ECO-Fast

Page 38 of 50

Final Report: June 3, 2010

As further testing was completed, all components performed every function specified within the  project proposal. The steering precisely controlled the vehicle at high and low speeds, and generated a turn radius of 19 ft. The front suspension provided vibration damping, braking, and steering mounting points. The rear suspension provided mounting locations for all associated components, provided excellent strength and rigidity. The main frame provided mounting locations for all trike components, as well as exceeding both strength and rigidity requirements. The gearing allowed any team member (and family, friends, colleagues, and several other  miscellaneous students) to climb on and propel the vehicle over any reasonable geography with relative ease. Additionally, the drive train allowed the vehicle to sustain speeds above 30mph without running out of gearing. In short, every expectation or requirement was met or exceeded the first time the components were assembled. Although some of the bushing may need to be upgraded before further more aggressive testing is undertaken, the outcome of the project is quite impressive, and exceedingly satisfactory for a prototype vehicle.

Team ECO-Fast

Page 39 of 50

Final Report: June 3, 2010

REFERENCES "ActionBent Recumbents - Tadpole Trike." ActionBent Recumbent Bikes. Web. Winter 2010. . "AERO Rider." Aerorider | Electric Tricycle | Velomobiel . Web. 03 Nov. 2009. .  Big Cat HPV - Creators of Catrike and Catbike. Web. Winter 2010. .

"Bump Steer." Wikipedia, the Free Encyclopedia. Web. Oct.-Nov. 2009. . Cab Bike. Web. 03 Nov. 2009. .

Eland, P. (1997). Tricycle steering geometry. Retrieved from http://www.eland.org.uk/steer_sheets.html The Go-one³ Is One of the Most Innovative Vehicles on the Sector of Ultralight Mobiles. Web. 03

 Nov. 2009. . "Greenspeed Recumbent Trikes - Glyde Velomobile." Greenspeed Recumbent Trikes - Welcome  Page. Web. 05 Nov. 2009. . ]\

Horwitz, Rickey. (2000). Build your own recumbent trike . Retrieved from http://www.ihpva.org/Projects/PracticalInnovations/index.html "Hugh Currin - Main." Oregon Institute of Technology | OIT, Bachelor's, Master's Degree  Programs, Distance Education, Portland, Klamath Falls, La Grande, Medford, Seattle.

Web. Spring 2010. . Ian. "Ian's Bicycle Wheel Analysis - Rim Strength." Astounding Web Pages - Hosted by Amos the Mbu Puffer Fish. Web. 14 Apr. 2010.

. Juvinall, Robert C., and Kurt M. Marshek. Fundamentals of Machine Component Design. 4th ed. Hoboken, NJ: John Wiley & Sons, 2006. Print.

Team ECO-Fast

Page 40 of 50

Final Report: June 3, 2010

"MatWeb - The Online Materials Information Resource." Online Materials Information  Resource - MatWeb. Web. 18 Jan. 2010.

.  McMaster-Carr . Web. Winter 2010. .  Pedal Yourself Healthy. Web. 03 Nov. 2009. .  Pilot Supplies, Avionics, and Homebuilt Aircraft Parts from Aircraft Spruce and Specialty Co.

Web. Winter 2010. .  Precision Spring Manufacturer - Century Spring Corp. Web. Winter 2010.

.  Recumbent Trikes and Recumbent Bikes - ICE - Home. Web. Winter 2010.

. Sims, I, & Sims, P. (Ed.). (1997). Greenspeed gtr 20/20 tourer trike plans. Ferntree Gully, Australia Sunrider Cycles - Velomobiel . Web. Winter 2010. .

Team ECO-Fast

Page 41 of 50

Final Report: June 3, 2010

SPONSORS AND OTHER HELP This project would not have been able to be undertaken, much less completed, without the help of our sponsors. Through their time and generous donations they have allowed the ECO-FAST team to design and build this senior project. A special thanks to the following for their time and support.

OIT MMET Department  OIT Resource Fee Hutch’s Bicycles of Klamath Falls Lou Tauber  Dr. David Culler  Calvin Collier  And the team members for their time and donations from their personal accounts

Team ECO-Fast

Page 42 of 50

 APPENDICES  Appendix A: Component List   Appendix B: Part Drawings  Appendix C: Project Costs/Bill of Materials  Appendix D: Calculations *Appendix not applicable at this time.

Final Report: June 3, 2010

 APPENDIX A: COMPONENT LIST The following Appendix includes all major materials designed or purchased to complete the main assembly of the frame. Some components are excluded from this list such as drive train components, seat fabric, seat cord, and other similar components. Figure 15 below demonstrates the part numbering system designed for the project and can be used to locate appropriate sections of this document. Detailed drawings of all designed and created parts can be found in Appendix B of this report and are labeled with the same numbering system as described below. Each part designed during the course of this project is included in this appendix in three formats; SolidWorks part file, SolidWorks 2D drawing File, and PDF 2D Drawing File.

Figure 15: Part Number Example

 APPENDIX A: COMPONENT LIST Main Frame Part #

Quantity

Revision

Orig. Date

P11-1-01

Bottom Section of Main Frame

1

3

4/10/2010

Yes

4/5/2010

DNA

P11-1-02

Front Section of Main Frame

1

3

4/10/2010

Yes

4/5/2010

DNA

P11-1-03

Back Section of Main Frame

1

3

4/10/2010

Yes

4/5/2010

DNA

P11-1-04

Tail Section of Main Frame

1

3

4/10/2010

Yes

4/5/2010

DNA

P11-1-05

Main Tube End Cap

2

3

4/10/2010

Yes

5/28/2010

DNA

P11-1-06

Main Frame Side Tube

2

3

4/10/2010

Yes

4/5/2010

DNA

P11-1-07

Steering Pivot

1

1

4/10/2010

Yes

4/28/2010

DNA

P11-1-08

Rear Swingarm Pivot

1

1

4/10/2010

Yes

4/25/2010

DNA

Upper Pedal Bracket

1

2

4/10/2010

Yes

5/20/2010

DNA

Quantity

Revision

Orig. Date

4 2 1 1 1 2 2

P11-1-09

Description

Rev. Date

Approved

Constructed

Purchased

Front Suspension Part #

Description

Rev. Date

Approved

Constructed

Purchased

P12-1-01

Bottom Spindle

2

Yes

5/8/2010

DNA

P12-1-02

Top Spindle

2

Yes

5/8/2010

DNA

P12-1-03

Bolt Guide Bushing

4

P12-1-04

Guide Bushing

4

Yes

5/12/2010

DNA

Yes

5/18/2010

DNA

P12-1-05

Guide Shaft

4

Yes

5/8/2010

DNA

P12-1-06

Steering Tube

2

P12-1-07

Head Tube

2

Yes

5/8/2010

DNA

Yes

5/8/2010

P12-1-08

Guide Bolts 1/2x13x3.5

4

Yes

P12-1-09

Steering Collars

2

Yes

P12-1-10

AHead Sets

2

Yes

P12-1-11

20mm Quick Release Through Axel

2

Yes

P12-1-12

Wheel

2

Yes

P12-1-13

Brake Caliper

2

Yes

P12-1-14

Brake Caliper Screws M5x0.8mm

4

Yes

 APPENDIX A: COMPONENT LIST Rear Suspension Part #

Description

Quantity

Rev. Date

Approved

Constructed

P13-1-01

Pivot Mount

4/13/2010

Revision

Orig. Date

YES

4/15/2010

DNA

P13-1-01

Purchased

P13-1-02

First Tube

4/13/2010

YES

4/15/2010

DNA

P13-1-02

P13-1-03

Second Tube

4/13/2010

YES

4/15/2010

DNA

P13-1-03

P13-1-04

Front Cross Member

4/13/2010

YES

4/15/2010

DNA

P13-1-04

P13-1-05

First Tube Right Side

4/13/2010

YES

4/15/2010

DNA

P13-1-05

P13-1-06

Second Tube Right Side

4/13/2010

YES

4/15/2010

DNA

P13-1-06 P13-1-07

P13-1-07

Left Dropout

4/13/2010

YES

4/30/2010

DNA

P13-1-08

Right Dropuot

4/13/2010

YES

4/30/2010

DNA

P13-1-08

P13-1-09

Second Cross Member

4/13/2010

YES

4/30/2010

DNA

P13-1-09 P13-1-10

P13-1-10

Shock Tab

4/13/2010

YES

5/2/2010

DNA

P13-1-11

Bottom Mount

4/21/2010

YES

4/25/2010

DNA

P13-1-11

P13-1-12

Main Rod

4/17/2010

YES

4/25/2010

DNA

P13-1-12 P13-1-13

P13-1-13

Threaded Washer

4/15/2010

YES

4/25/2010

DNA

P13-1-14

Intermediate Sleeve

4/15/2010

YES

4/25/2010

DNA

P13-1-14

P13-1-15

Middle Washer

4/15/2010

YES

4/25/2010

DNA

P13-1-15 P13-1-16

P13-1-16

Washer

4/16/2010

YES

4/26/2010

DNA

P13-1-17

Top Sleeve

4/22/2010

YES

4/26/2010

DNA

P13-1-17

P13-1-18

Top Cone

4/25/2010

YES

4/30/2010

DNA

P13-1-18

4/30/2010

DNA

P13-1-19

P13-1-19

Top Washer

4/24/2010

YES

 APPENDIX A: COMPONENT LIST Rear Suspension Part #

Description

Quantity

Rev. Date

Approved

Constructed

P13-1-01

Pivot Mount

4/13/2010

Revision

Orig. Date

YES

4/15/2010

DNA

P13-1-01

Purchased

P13-1-02

First Tube

4/13/2010

YES

4/15/2010

DNA

P13-1-02

P13-1-03

Second Tube

4/13/2010

YES

4/15/2010

DNA

P13-1-03

P13-1-04

Front Cross Member

4/13/2010

YES

4/15/2010

DNA

P13-1-04

P13-1-05

First Tube Right Side

4/13/2010

YES

4/15/2010

DNA

P13-1-05

P13-1-06

Second Tube Right Side

4/13/2010

YES

4/15/2010

DNA

P13-1-06 P13-1-07

P13-1-07

Left Dropout

4/13/2010

YES

4/30/2010

DNA

P13-1-08

Right Dropuot

4/13/2010

YES

4/30/2010

DNA

P13-1-08

P13-1-09

Second Cross Member

4/13/2010

YES

4/30/2010

DNA

P13-1-09 P13-1-10

P13-1-10

Shock Tab

4/13/2010

YES

5/2/2010

DNA

P13-1-11

Bottom Mount

4/21/2010

YES

4/25/2010

DNA

P13-1-11

P13-1-12

Main Rod

4/17/2010

YES

4/25/2010

DNA

P13-1-12 P13-1-13

P13-1-13

Threaded Washer

4/15/2010

YES

4/25/2010

DNA

P13-1-14

Intermediate Sleeve

4/15/2010

YES

4/25/2010

DNA

P13-1-14

P13-1-15

Middle Washer

4/15/2010

YES

4/25/2010

DNA

P13-1-15 P13-1-16

P13-1-16

Washer

4/16/2010

YES

4/26/2010

DNA

P13-1-17

Top Sleeve

4/22/2010

YES

4/26/2010

DNA

P13-1-17

P13-1-18

Top Cone

4/25/2010

YES

4/30/2010

DNA

P13-1-18 P13-1-19

P13-1-19

Top Washer

4/24/2010

YES

4/30/2010

DNA

P13-2-01

Primary Elastomer

DNA

DNA

DNA

3/12/2010

P13-2-01

P13-2-02

Secondary Elastomer

DNA

DNA

DNA

P13-2-02

P13-1-01

Pivot Mount

4/13/2010

YES

4/15/2010

3/12/2010 DNA

P13-1-01

P13-1-02

First Tube

4/13/2010

YES

4/15/2010

DNA

P13-1-02

P13-1-03

Second Tube

4/13/2010

YES

4/15/2010

DNA

P13-1-03

Rev. Date

Approved

Constructed

 APPENDIX A: COMPONENT LIST Steering Part #

Description

Quantity

Revision

Orig. Date

P14-1-01

Steering Top Bar

2

1

4/3/2010

Purchased

P14-1-02

Steering Main Bar

1

1

4/3/2010

P14-1-03

Steering Connection Tube

1

1

4/3/2010

P14-1-04

Steering to Linkage Tube

1

1

4/3/2010

P14-1-05

Linkage

3

1

P14-1-06

Delrin Bushing Steering

1

P14-1-07

Steering Pivit Plate

1

P14-2-01

1

Yes

P14-2-02

1/2 x 20 tpi x 3-3/4 Bolt (Bars to Frame) 7/16 x 20 tpi x 2-3/4 Bolt (Pivot Plate to Frame)

1

Yes

P14-2-03

7/16 x 20 tpix 1-1/2 Bolt (Rod End Con.)

6

Yes

P14-2-04

1/2 x 20 tpi Nut

1

Yes

P14-2-05

1/2 Washer

2

Yes

P14-2-06

7/16 x 20 tpi Nut

6

Yes

P14-2-07

7/16 Washer

6

Yes

P14-2-08

7/16 x 20 tpi Rod End

6

Yes

Yes

4/23/2010

DNA

Yes

4/23/2010

DNA

Yes

4/23/2010

DNA

Yes

4/23/2010

DNA

5/20/2010

Yes

5/20/2010

DNA

1

4/3/2010

Yes

4/23/2010

DNA

2

4/3/2010

Yes

5/23/2010

DNA

5/15/2010 5/15/2010

5/15/2010

 APPENDIX A: COMPONENT LIST Steering Part #

Description

Quantity

Revision

Orig. Date

P14-1-01

Steering Top Bar

2

1

4/3/2010

Rev. Date

Approved

Constructed

Purchased

P14-1-02

Steering Main Bar

1

1

4/3/2010

P14-1-03

Steering Connection Tube

1

1

4/3/2010

P14-1-04

Steering to Linkage Tube

1

1

4/3/2010

P14-1-05

Linkage

3

1

P14-1-06

Delrin Bushing Steering

1

P14-1-07

Steering Pivit Plate

1

P14-2-01

1

Yes

P14-2-02

1/2 x 20 tpi x 3-3/4 Bolt (Bars to Frame) 7/16 x 20 tpi x 2-3/4 Bolt (Pivot Plate to Frame)

1

Yes

P14-2-03

7/16 x 20 tpix 1-1/2 Bolt (Rod End Con.)

6

Yes

P14-2-04

1/2 x 20 tpi Nut

1

Yes

P14-2-05

1/2 Washer

2

Yes

P14-2-06

7/16 x 20 tpi Nut

6

Yes

P14-2-07

7/16 Washer

6

Yes

P14-2-08

7/16 x 20 tpi Rod End

6

Yes

Yes

4/23/2010

DNA

Yes

4/23/2010

DNA

Yes

4/23/2010

DNA

Yes

4/23/2010

DNA

5/20/2010

Yes

5/20/2010

DNA

1

4/3/2010

Yes

4/23/2010

DNA

2

4/3/2010

Yes

5/23/2010

DNA

5/15/2010 5/15/2010

5/15/2010

Seat Part #

Description

Quantity

Revision

Orig. Date

Rev. Date

Approved

Constructed

Purchased

P15-1-02

Seat Bottom Side Tube

2

4/26/2010

Yes

DNA

P15-1-01

Seatback Side Tube

2

4/26/2010

Yes

DNA

P15-1-03

Seat Bottom Cross Member

2

4/26/2010

Yes

DNA

P15-1-04

Seat Back Cross Member

2

4/26/2010

Yes

DNA

P15-1-05

Seat Pivot Sleeve

2

4/26/2010

Yes

DNA

P15-1-06

Seat Pivot Delrin

2

4/26/2010

Yes

DNA

P15-2-01

1/4 x 20 tpi 1-1/2 Bolt (pivots/back bracket)

4

Yes

1/4 x 20 tpi Nut

5

Yes

P15-2-03

1/4 Washer

8

Yes

P15-2-04

1/4 x 20 tpi 2-1/2 Bolt (back bracket-frame)

1

Yes

P15-2-05

3/8 x 16 tpi 2-1/2 Bolt (bottom to frame)

1

Yes

P15-2-06

3/8 x 16 tpi Nut

1

Yes

P15-2-06

3/8 Washer

4

Yes

P15-2-07

Heim Joints

3

Yes

 APPENDIX A: COMPONENT LIST P15-2-02

 APPENDIX A: COMPONENT LIST 1/4 x 20 tpi Nut

5

Yes

P15-2-03

1/4 Washer

8

Yes

P15-2-04

1/4 x 20 tpi 2-1/2 Bolt (back bracket-frame)

1

Yes

P15-2-05

3/8 x 16 tpi 2-1/2 Bolt (bottom to frame)

1

Yes

P15-2-06

3/8 x 16 tpi Nut

1

Yes

P15-2-06

3/8 Washer

4

Yes

P15-2-07

Heim Joints

3

Yes

P15-2-02

 APPENDIX B: P ART DRAWINGS The following Appendix includes hard copies of all working drawings used in the construction of  the velomobile. Digital copies are also available in both SolidWorks® and .pdf formats. Located inside the Major Design Components folder, folders compiling the Main F rame, Front Suspension, Rear Suspension, Seat, and Steering are available. Each design component folder  contains all of the SolidWorks® parts created for each component. Also located inside each design component folder is a sub-folder containing 2D drawing files. Upon accessing the drawing files folder an additional two folders are available: one containing the drawing files in .pdf format and the other in SolidWorks® format.

 APPENDIX B: P ART DRAWINGS The following Appendix includes hard copies of all working drawings used in the construction of  the velomobile. Digital copies are also available in both SolidWorks® and .pdf formats. Located inside the Major Design Components folder, folders compiling the Main F rame, Front Suspension, Rear Suspension, Seat, and Steering are available. Each design component folder  contains all of the SolidWorks® parts created for each component. Also located inside each design component folder is a sub-folder containing 2D drawing files. Upon accessing the drawing files folder an additional two folders are available: one containing the drawing files in .pdf format and the other in SolidWorks® format.

 APPENDIX C: PROJECT COSTS $819.96

Grand Total

Supplier BOTH-Spruce BOTH -Spruce BOTH -Spruce BOTH -Spruce BOTH -Spruce BOTH -Spruce WEST -Spruce EAST - Spruce BOTH -Spruce BOTH -Spruce McMasters McMasters McMasters Electric Scooter Electric Scooter Wicks Aircraft Supply PricePoint Hutch's Bicycles Hutch's Bicycles Hutch's Bicycles Hutch's Bicycles Hutch's Bicycles Hutch's Bicycles Hutch's Bicycles

Part # Steering Steering Steering Front Susp. Front Susp. Front Susp. Main Frame Bottom Bracket Main Frame Seat Tubing

03-05400

04-01646 03-02700 03-07200 02-52114 03-20700 03-10300 03-09110 03-09100 03-04400

1658T47 Steering 1064K551 Steering Steering 26035A234 Steering Comp. Steering Comp. RC1X2X065Rear Susp. 41 42074 Front Susp. BH BC Claws SHI FH_RM30 NA NA NA

Discription 4130 STEEL TUBE 7/8" X.049 6FT FLANGED BUSHING FB46-02 4130 STEEL TUBE 1/2X.065 1FT 4130 STEEL TUBE 1-1/8" X .065 1FT DELRIN ROD 1-1/4" (NATURAL) 1FT 4130 ROUND STEEL ROD 1/2" 1FT 4130 TUBE 1-3/4"X.065

Price/unit 2.67 0.19 3.17 3.67 6.85 2.4 7.6

4130 STEEL TUBE 1-1/2X.083 1FT 4130 STEEL TUBE 1-1/2X.065 4FT 4130 STEEL TUBE 3/4" X .049 9FT 6063 ALUMINUM TUBE 9/16 X .118 8FT Right Hand Rod End 7/16 -20 Right Hand Tap 7/16 -20 Breaks with Electric Cut Off Switch Throttle

5.25 4 1.85 10.59 8.15 4.15 56.9 49.99

4130 Rectangular 1"X2"X.065" Can Creek Headset Brake Housing per ft Brake Cables 16Tx3/32" Free Wheel

10.12 29.98 1 4 1

36x135mm 8sp RR Hub SRAM Dual Drive Hub Steel Track Cog COG Track 20Tx3/32

1 1 1 1

Quantity 8 12 2 2 2 3 8 1 6 16 1 6 1 1 1 5 2 10 4 22 15 260 8 30 total

total $21.36 $2.28 $6.34 $7.34 $13.70 $7.20 $60.80 $5.25 $24.00 $29.60 $10.59 $48.90 $4.15 $56.90 $49.99

Sub Total

$177.87

$63.64 $106.89

$50.60 $59.96 $10.00 $16.00 $22.00 $15.00 $260.00 $8.00 $30.00

$50.60 $59.96

$361.00 $819.96

 APPENDIX D: STRESS C ALCULATIONS The following Appendix contains sample hard copies of the hand calculations performed to determine loading and stress analysis. Hand calculations are also available in .pdf format in the Major Design Components folder. Each design component folder will contain a sub-folder with the available hand calculations for each design component.