# nd Avenue Surrey, British Columbia, V3T 0A3. Maureen Hindy Faculty of Engineering, Simon Fraser University Central City Galleria 4

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1 Department of Mechatronics Systems Engineering Simon Fraser University Avenue Surrey, BC V3T 0A3 # nd Avenue Surrey, British Columbia, V3T 0A3 Maureen Hindy Faculty of Engineering, Simon Fraser University Central City Galleria 4 July 29, 2013 Re: SF-1 Mechanical Final Technical Report Dear Ms. Hindy, The following document, SF-1 Mechanical Final Technical Report, outlines our capstone project for MSE 411w. Our goal was to finish the design and start construction of the car over the 8 month capstone period. Our plan is to have to car ready to race at Formula SAE next May. This proposal will provide an overview of the final design and construction, financial analysis which includes competition, transportation and building costs. Furthermore, the sources of sponsorship and funding will be outlined with detailed information on project scheduling. The design choices will be explored and thoroughly explained, along with the shortcomings and roadblocks that the team encountered along the way. Our Mechanical design team consists of four multi-talented individuals: Batuhan Atalay, George Ioannou, Richard Douglas and Spencer Steele. Each team member brings his own set of skills and experience to the team. As 4 th year capstone students, we are all very determined and motivated to leave a legacy at SFU. Sincerely, George Ioannou Batuhan Atalay Richard Douglas Spencer Steele SF-1 Mechanical Design Team Enclosure: SF-1 Mechanical Final Technical Report SF-1 Engineering

2 SF-1 Mechanical Final Technical Report July 29, 2013 Richard Douglas Spencer Steele George Ioannou Batuhan Atalay

3 EXECUTIVE SUMMARY The final technical report outlines the specific components that have been designed, fabricated and installed in the first SF-1 car. The sections covered are the chassis, suspension, powertrain, drivetrain, steering and brakes. Within the large sections are the details and design methods that have been implemented through the previous 8 months of this Capstone project. The team budget is highlighted showcasing the partnerships formed to date, how the budget has been utilized thus far and future predictions on additional costs including those of the race events in 2014 and additional part/space needs. The powertrain consists of a 600cc Yamaha engine with a 6-speed transmission and the drivetrain is equipped with a torsen differential and provides a 3.5:1 gear ratio. The steering rack is mounted near the dashboard to allow the maximum amount of space for the driver to reach and operate the foot pedals. The steering wheel is a lightweight gokart wheel that has the compatibility for the future integration of paddle shifters. The control arms are made from alloy steel and connected to the chassis using spherical joints (ball ends). Rigorous testing with FEA in Solidworks was conducted to prove the strength characteristics. The shocks and springs are Fox Vanilla RC mountain bike shocks and are mounted one per wheel provided independent suspension. Providing driver safety are the brakes that consist of Brembo calipers, Willwood master cylinders and are providing stopping power to custom fabricated rotors. Additionally, due to the large inclination of the driver s seat a 6-point harness is used to secure the driver to the seat. All of the components come together and are assembled on an aluminum monocoque chassis fabricated using 6061 T6 aluminum. Aluminum was chosen as the foundation of the majority of our components due to its high strength and extremely light weight characteristics. i

4 TABLE OF CONTENTS 1.0 Definition of Terms iv 2.0 Introduction Timeline Long Term Product Goals & Schedule Budget Build and Marketing Budget Power Train Engine Transmission Drive Train Drive Train Components Suspension General Suspension Suspension Components Miscellaneous Steering General Steering Steering Components Brakes General Specifications Brake Components Wheels and Tires Chassis Design & Stress Analysis Key Technologies, and Safety & Other Features Safety Integration Key Technologies Conclusion References 34 Appendix A: Sample Sponsorship Package (Circulated to potential sponsors) 36 Appendix B: Bill of Materials 38 Appendix C: Suspension 40 ii

5 TABLE OF FIGURES Figure 1: Production Timeline 3 Figure 2: The powerful Yamaha YZF 600 Engine, in our bespoke engine test stand at our Auto Show booth 5 Figure 3: Sample dynamometer readout for YXF-R6 engine 6 Figure 4: An example Fuel Restriction System (Designed by Dalhousie FSAE Team) 6 Figure 5: -AN Fittings with Braided Stainless Steel Fuel Lines 7 Figure 6: One of the Twin Side Mounted Aluminum Radiators 8 Figure 7: An FSAE Competitor s Paddle Shifter Design 9 Figure 8: Differential Assembly including rear brake caliper 10 Figure 9: Typical constant velocity shaft 10 Figure 10: Aluminum CV Tripod Housing 11 Figure 11: Output sprocket - 3.5:1 Ratio 11 Figure 12: Exploded View of Differential Assembly 12 Figure 13: Typical FSAE front suspension [photo credit: MotoIQ.com] 13 Figure 14: Rendering of SF-1 front suspension (pushrod delete) 15 Figure 15: Rendering of SF-1 Rear Suspension (pushrod delete) 15 Figure 16: Rendering of SF-1 Front Bellcrank 17 Figure 17: Original Steering Design 18 Figure 18: Ackermann Geometry 19 Figure 19: Woodward Type MC Rack & Pinion Steering Shaft 20 Figure 20: New steering design 20 Figure 21: Wilwood brake components with custom set-up 21 Figure 22: Wilwood GP200 Brake Caliper 22 Figure 23: Cross-drilled & slotted brake rotor 22 Figure 24: SolidWorks rendering and photo of SF-1 rims for rain tires 23 Figure 25: Preliminary Chassis Rendering - March Figure 26: FEA Analysis on the Chassis in SolidWorks 26 Figure 27: Finalized Chassis Design 27 Figure 28: Chassis under construction in a Jig 28 Figure 29: Welding the Chassis 28 Figure 30: Chassis nearing completion - July Figure 31: Minimum roll hoop clearance 30 iii

6 1.0 DEFINITION OF TERMS Alternative frame Bulkhead Control Arm DOHC FEA Front roll hoop FSAE Main roll hoop Master cylinder SAE Slicks SPST SRCF Throttle Track Upright Wheelbase A frame which differs from a steel space frame in either material or design, or both. That frame section, resembling a planar section, which is situated immediately forward of the driver s foot controls. In a suspension system, connects the steering knuckle with the chassis and locates each axle. A suspension requires top and bottom control arms at each applicable corner of the car. AKA wishbone, A-arm. Dual Overhead Camshaft or Double Overhead Camshaft. Finite Element Analysis; a numerical form of stress analysis normally used when analytical stress analysis might be prohibitively complex or impossible. The hoop installed over the driver s legs to protect the driver in case of a rollover. Formula SAE, the competition into which SF-1 is entering. The steel tubing hoop installed over/behind the driver s head to protect the driver in case of a rollover. The component of the brake system which converts force applied to the brake pedal by the driver to hydraulic brake pressure for purposes of activating the service brakes. Society of Automotive Engineers A term generally used for a racing tire. Single pole, single throw (electrical switch classification). Structural Requirements Certification Form, a document outlining the performance analysis which might be performed on an alternative frame. A device used for metering air intake, and subsequently, fuel intake, to the engine; controlled by accelerator pedal. The measurement from the center of one wheel to the center of the opposite wheel on the same axle. The piece of a control arm suspension which links the top and bottom arms, as well as provides a mounting point for the bearing hub. The measurement from the center of the front wheels to the center of the rear wheels. iv

7 2.0 INTRODUCTION This Final Technical Report marks a significant milestone in the overall design and construction of the SF-1 race car. As expected, the mechanical division faced a significant design task, fraught with challenges. Many of the designs aspects revolve around the parts which need to be sourced for various sub-systems. Sourcing parts is fast becoming an attractive option for our team as opposed to fabrication, as time is a significant constraint. In many cases, sourcing parts from retail vendors proves to be less expensive than custom fabrication. Due to the many sub-systems in the SF-1 car, the team must undertake a high-level design perspective. As such, many sub-section details in this report involve the specification of parts which are available from distributors, several of whom sponsor the SF-1 team. Also pertaining to this fact, some sub-systems for which engineering is not yet completed are outlined rather than specified. In these cases, constraints are given in place of dimensions. 1

8 3.0 TIMELINE 3.1 Long Term Product Goals & Schedule The major goal of the team was to establish an FSAE team at SFU. We feel we have done well in accomplishing this goal. From this point onwards the main goal it to finish fabrication on the car and start testing with a couple months to spare prior to the Michigan and Nebraska competitions. As seen on the timeline below (figure 4), the design on the major systems of the car is already complete. Chassis and powertrain design is complete and fabrication and machining has begun at both the MRX Marine shop and MSE Machining and Testing Center. The suspension, steering, brake and body fabrication will start mid-august and continue on into the beginning of September at which point the overall assembly and integration will begin. Assembly and integration should take the team well into the middle of October. This period of time may be prolonged if parts do not pass track testing. By the end of October, testing should commence before the rainy season starts and track conditions are not ideal. The testing will most likely carry on for a matter of months along with iterative design on parts that do not work out. The Michigan Competition takes place from May 8-11th 2014 and the Nebraska competition takes place May 18 th -22 nd. An additional 3 days must be allocated for transporting the car to competition as well as a consecutive 3 for transporting it back after competition. 2

9 SF-1 Timeline Chassis Design Chassis Fabrication Powertrain Design Powertrain Machining Suspension Design Suspension Fabrication Brake & Steering Design Brake & Steering Fabrication Body Design Body Fabrication Overall Assembly & Integration Testing Design Days Completed Design Days Remaining Fabrication Days Completed Fabrication Days Remaining Assembly Time Testing Time Competition Planning Renovations Michagan Competition Lincoln Competition Space Acquisition Figure 1: Production Timeline 3

10 4.0 BUDGET 4.1 Build and Marketing Budget At these final stages of the project SF-1 has accumulated over 15 sponsors and funding in the range of $10,000 (this includes part discounts and donations). Some of our companies include: Lordco who provides substantial discounts on parts, Knighthill Automotive who has offered to paint and detail our bodywork, BatteryWorld who donated a custom motorcycle battery and many more. A detailed list of all the sponsors can be found in Appendix A. Purchases made to date for all the components that are outlined through the report have cost roughly $7000 with a detailed breakdown presented in Appendix B. Our costs include those of machine shop hours, material stock, fasteners and marketing methods (t-shirts, business cards etc.). Future costs have been predicted and we are still within our budget of $10,000 with roughly $3,000 remaining and several sponsorships still pending. For a project such as this, business and marketing aspects are ongoing and new partnerships are continuously being sought after. 4.2 Event Costs Event costs have been estimated using information from the SAE website and also from research we conducted on the internet. The value on the table includes a $2000 entry fee, projected fuel transportation costs to/from Nebraska, trailer rental fees, hotel bookings, and food. In consideration that we will be competing in 2014 we understand that these costs might vary at the time of competition. Hotel pricing was found using online booking websites and estimating prices for the competition period in

11 6.0 POWER TRAIN 6.1 Engine General Specifications 610cc is the maximum engine displacement allowed in competition. We chose a Yamaha YZF- 600R motorcycle engine for a number of reasons. The Yamaha 600cc is one of the best engineered engines around that is relatively close to our maximum engine displacement. Parts for it can be found off the shelf relatively easily and inexpensively. The SF-1 team uses a bespoke, student-built test stand for storage and testing purposes when the engine is out of the car, shown here on display at the 2013 Vancouver International Auto Show: Figure 2: The powerful Yamaha YZF 600 Engine, in our bespoke engine test stand at our Auto Show booth Our 599cc displacement combined with liquid cooling, DOHC, and 16 valve configuration make it a very responsive engine perfect for high performance applications. The Yamaha 600 also has a very nice power curve 10 as seen in figure 1, below: 5

12 Figure 3: Sample dynamometer readout for YXF-R6 engine The stock engine is capable of outputting 85 horsepower under normally aspirated conditions. Our engine came stock with a set of 4 single barreled carburetors. Carburetion is our existing method of fuel delivery but we have plans to upgrade later to a custom mega squirt fuel injection system complete with a mapable ECU Intake Restrictor Because of competition rules, all intake air to the engine must pass through a 20mm diameter circular ring which will be the last point of contact for the flowing air before it is delivered into the individual intake valves of the cylinders. This restrictor will be installed between the throttling device and the cylinder head. Carbon fiber and aluminum will likely be the material of choice for their weight properties. Figure 4: An example Fuel Restriction System (Designed by Dalhousie FSAE Team) 6

13 6.1.3 Fuel Supply & Delivery The fuel tank itself is designed out of 1/8 aluminum sheet metal and features a site tube and manual fuel cap as required by competition rules. The overall fuel capacity of 2 gallons will supply more than enough fuel for even the most gruelling events (i.e. FSAE Endurance). Hard stainless steel fuel lines will be used in combination with flexible fuel hose to deliver the fuel from the tank to the carburetion system. Military grade AN Fuel fittings will be used wherever possible to ensure fuel system reliability and integrity. These will be designed and installed after most of the other major components. The fuel system will also feature an inline racing fuel pump with a replaceable FRAM fuel filter that can be easily inspected before races. Figure 5: -AN Fittings with Braided Stainless Steel Fuel Lines Cooling System To cool the engine, two 12.5 x15 aluminum radiators will be located on either side of the engine in line with the main roll hoop. The chassis will provide not only structural support but airflow to the radiators using a unique formula one style duct. Both radiators come equipped with cooling fans which will keep the engine at an optimum operating temperature while idling in a hot Michigan spring on the tarmac. 7

14 Figure 6: One of the Twin Side Mounted Aluminum Radiators 6.2 Transmission General Specifications One of the reasons we decided to go for a motorcycle engine was because they are already designed with a complete gear transmission. In our case, the Yamaha engine is coupled to a 6 speed sequential transmission. This will provide a wide range of operating speeds at which the car can be driven through variable track setups Shifting A custom paddle shift system is being designed for the original Yamaha 6 speed transmission. While still in the preliminary design stages, the plan is to incorporate a stepper motor and a gear reduction system to take the place of shifter linkage. Shift Paddles will be located behind the steering wheel. 8

15 Figure 7: An FSAE Competitor s Paddle Shifter Design Clutch Clutch control will be integrated into the paddle shifter design and automatically actuated using a solenoid thus reducing shift times and the chance for operator error. As this design a huge endeavor and may not see completion in time for 2014 competition a standard cable clutch system may be utilized. If this turns out to be the case an integrated hand shifter located in the driver cockpit will be used as opposed to a foot operated setup. The main advantage of this will be a more natural and faster clutch actuation. 9

16 7.0 DRIVE TRAIN 7.1 Drive Train Components Differential The power distribution to our rear wheels will be done using an Audi A4 Torsen differential with helical gears. The differential has already been sourced from a donor car, so specifying the materials used in its construction would be redundant. Additionally, the differential case is presumably made from a different material than the internals. Torsen differential of this category are exceptional for increasing internal friction. This is used for higher torque applications but can lead to rare instances of backlash occurring. The Torsen design allows for a speed differential effect when cornering, such that the outer wheel rotates at a higher velocity than the inner, while more torque is applied to the inner wheel. The Torsen housing will also be used to mount the rear brake. Instead of mounting an individual brake on each of the rear wheels, a single inboard brake on the output gear itself is used. The limited-slip operation of the Torsen means that applying the brakes will stop the rotation of the output gear, stopping both rear wheels simultaneously. In the figure above you can see a rendering of the differential and the housing that encompasses it. The 5-finger plate that is visible on the front is where the sprocket for the chain drive is mounted. Figure 8: Differential Assembly including rear brake caliper CV Shafts Refer to the following diagram. The CV (constant velocity) shafts consist of a steel shaft (B in the diagram) with a male spline on each end. Between the centre shaft and each end spline is a CV joint. Each Figure 9: Typical constant velocity shaft 10

17 joint is a different type: the inner joint is a tripod joint (C), which can be modeled as a revolute joint in series with a prismatic joint to allow the CV shaft to change length as the suspension articulates. The outer joint is a Rzeppa-type joint (A), which is purely revolute. To save weight while handling high torque, the shaft will be constructed of alloy steel. The splines will both be heat-treated to ensure sufficient surface hardness for wear resistance. Replacing the tripod housing located between B and C above is the custom housing that you see on your right (Figure 10). This aluminum housing is bolted directly onto the output of the torsen differential and does not require the use of the male splines at C. By doing so, the team was able to reduce the weight of the assembly even further and implement another aspect of innovation Chain Drive Our final drive ratio is a pleasant midpoint between quick acceleration and top-line speed. Through optimization in regards to size of the sprocket and top speed it was selected at 3.5:1. The sprocket is mounted on the 5-finger plate that is shown in Figure 8 above and also acts as the rotor for the rear brake. The sprocket is made from steel alloy to ensure that it can withstand the constant torque loading while also enduring the high temperature variations caused by braking. It is ¼ thick and weighs ~5lbs. A chain drive system Figure 10: Aluminum CV Tripod Housing Figure 11: Output sprocket - 3.5:1 Ratio requires regular lubrication and a braking surface must be dry at all times therefore a regular motorcycle chain is not compatible as it would coat the sprocket in chain lubricant rendering the brake inactive. To solve this issue a #530 O-ring chain has been installed. The chain has rubber 11

18 O-rings built between the outside link plate and inside roller link plates. These rubber fixtures form a barrier that holds factory applied lubricant grease inside of the pin and bushing wear areas. This eliminates the need for manual lubrication and also prevents external contaminants including dirt to enter the inside of the chain linkages where such particles could lead to increased wear and a shortened product life. Differential Mount Floating Caliper Axle Stub Tripod Housing Aluminum Housing Torsen Gears Sprocket Figure 12: Exploded View of Differential Assembly 12

19 8.0 SUSPENSION 8.1 General Suspension The SF-1 suspension will use a double-wishbone setup front and rear. The basic design of this layout has been the staple of international Formula-1 teams for years, and the innovation has trickled down to the amateur classes. The shock/ spring assembly at each corner is actuated via a push rod, ligntening the articulating mass as opposed to using an outboard coil-over. For a sample illustration, see the following diagram: Figure 13: Typical FSAE front suspension [photo credit: MotoIQ.com] The letters A-E will be used in reference to this drawing throughout the description of the 13

20 8.2 Suspension Components Control Arms The control arms (E in the above diagram) are made of mild steel and connected to the chassis using spherical joints (ball ends). Alloy steel was originally specified, but after completing stress analysis on the suspension, we found that mild steel would maintain a reasonable factor of safety. Due to its being much cheaper than alloy alternatives, mild steel was selected. All rod ends and spherical bearings; as well ¼ pipe (sch. 40) has been ordered and shipped; fabrication will begin on the suspension once the chassis is complete. The following specifications apply to the control arms in general: 1. The front track is set to 53 ; the rear, 51. This complies with the FSAE regulation that rear track is within 75% of front track. 2. The spherical joints and bell cranks are loaded in double shear. The following notes apply to the front control arms only: 1. Staying within the track width requirement, there is a minimum of 16 between the pickup points of left and right side control arms to allow room for the driver s feet and foot controls. 2. The geometry has been designed such that undesirable performance, such that jacking effect and bump steer, is reduced as much as possible during cornering. Ideally, the outside tire undergoes a negative camber attitude. The following notes apply to the rear control arms only: 1. Staying within the 51 track specification, is a minimum of 26 between the pick-up points of left and right side control arms to allow room for the powertrain. 2. Because the driver receives all steering input from the front wheels, no scrub radius or caster angle is necessary for the rear suspension. The geometry has therefore been engineered such that there is a minimum scrub radius and caster in the rear, although this is slightly compromised by the wheels being used. 3. The geometry has been designed such that undesirable performance, such that jacking effect, is reduced as much as possible during cornering. 14

21 Figure 14: Rendering of SF-1 front suspension (pushrod delete) Figure 15: Rendering of SF-1 Rear Suspension (pushrod delete) 15

22 8.2.2 Uprights Uprights (C in the above diagram) constructed from cast aluminium have been obtained. The purpose of the upright is to provide the fourth bar (actuator bar) in the four-bar linkage that makes up the suspension geometry; the upright also houses the wheel bearing, and provision for mounting the brake caliper, and steering components. They were purchased off-the-shelf after careful deliberation by the SF-1 suspension specialist. Brackets have been engineered by SF-1 s suspension specialist, which will connect the uprights to the control arms via a set of high-misalignment spherical bearings. These brackets have been engineered for strength, light weight, and simplicity in manufacture. They are constructed from 1.5 x2.5 x0.100 wall steel box section. They were designed so that their manufacture requires only two cutting and two drilling operations Push Rods The push rods, like the control arms, will be made from mild steel ¼ pipe for high strength and fatigue resistance (D in the example diagram). Their dimension will depend on the dimensions of the control arms, wheel track on the respective axle, and desired configuration of the spring/ shock assembly. The push rod will be connected with a spherical joint at each end, to be lubricated before each dynamic event Shock & Spring Assembly The shock and spring will be a single integrated unit (A in the example diagram). This may be either a coil-over shock design or an air-charged shock design (airbag spring). The assembly, in concert with the push rod geometry, will allow a minimum of 1 inch of travel in each direction, jounce and rebound, from the suspension s neutral position. Fox Vanilla mountain bike shocks are an ideal choice for this. 16

23 8.2.1 Bell Crank The bell crank (B in the example diagram) will be machined from aluminium billet. It must include at least three bores: one for the pivot point, one for push rod attachment, and one for spring/ shock attachment. A fourth bore may be added if the team decides to include a sway bar in the suspension design. The bell crank will include a grease nipple and/or a bronze bushing at the pivot point for wear resistance. Figure 16: Rendering of SF-1 Front Bellcrank 8.3 Miscellaneous SolidWorks was used to create sketches used in finding the correct suspension geometry for finding roll center, roll center height, caster angle, and control arm length; as well as solving the suspension geometry. Please see the Appendix for a sample of these sketches. 17

24 9.0 STEERING 9.1 General Steering The steering saw substantial alterations since the beginning of the design stage. The biggest change happened in the overall steering design concept. Originally, we planned to have a floor mounted steering rack with a double u-joint shaft coupling it to the steering wheel. Because of the lack of space in the nose compartment of the vehicle, and the need to reach the throttle and brake pedals comfortably, we decided to remove the steering rack from its original location on the floor, and mount it close to the dashboard with the help of a bracket. This created more space in the nose compartment, and also eliminated the need for a complicated shaft coupling system. Figure 17: Original Steering Design The trade-off of this design alteration was the need to calculate new steering knuckles, as well as re-work the steering geometry in order to satisfy Ackermann steering. 18

25 Ackermann Steering is the geometric design of the steering system where the front tires are able to turn at different angles in order to complete a turn without over or under-steering. The steering arms and the tie-rod angles were designed with the Ackermann geometry in mind. Figure 18: Ackermann Geometry 9.2 Steering Components Steering Rack Modern road vehicles have complex steering systems. These are designed around the comfort of the driver and include components as hydraulic steering, adjustable steering columns, etc. Having the lightweight of our vehicle in mind, we resorted to a non-hydraulic system. A manual rack-and-pinion steering rack was sourced from BMS Inc. This steering rack offered all our design criteria, as it was a manual rack with a centre mounted shaft. It also offered the rack ratio necessary (3.4in/rev) for hard, auto-cross steering geometry. 19

26 Figure 19: Woodward Type MC Rack & Pinion Steering Shaft Tie Rods We used suspension tie-rods to mount to the steering rack, as we had the option of using any threaded tie-rod that would satisfy the geometry. The same size tie-rods came in very handy, as we were able to fabricate many of our suspension and steering geometries without having to source new parts Steering Wheel & Shaft A lightweight steering wheel was sourced online and coupled to a quick release unit, which we purchased from Dan s Performance Parts. The steering shaft was chosen to be 5/8 in diameter in order to match the steering rack output shaft. Figure 20: New steering design 20

27 10.0 BRAKES 10.1 General Specifications Braking is a vital component of any automobile, and safety is the primary concern of the FSAE competition. Therefore the brakes must have the capability of stopping the car from speeds in excess of 200 km/h within a very short distance. One of the key ways we reduced more weight on the car will be to run a pair of disc brakes on the front wheels while only using a single differential mounted disc brake. This simplifies the design by removing the additional brake and reduces the overall weight of the car, as well as the unsprung mass of the rear suspension. The braking system is broken down into the following sections: master cylinder, calipers, pads, rotors, and brake lines Brake Components Master Cylinder Two individual pedals were purchased from Wilwood for actuating the throttle and the brakes. Both master cylinders are actuated from the same brake pedal by running them tandem with a custom bracket. These master cylinders control the front and rear brake lines, and their pressure will be adjusted dynamically, in order to get proper braking from both axles. Figure 21: Wilwood brake components with custom set-up 21

28 Calipers & Pads Individual brake calipers provide the braking on the front wheels while the rear will be stopped by one larger central mounted caliper. For the front, we chose the Brembo P34 calipers which are lightweight and have large Figure 22: Wilwood GP200 Brake Caliper cylinders that can handle up to 11 to provide the performance braking SF-1 requires. Stock pads will be used with the P34 calipers A stock Tokico dual piston caliper normally found on Honda 600cc street bike will be used on the rear sprotor. Stock pads will be the braking pad of choice Rotors All brake rotors are custom designed to fit inside our wheel opening, and match the bolt pattern of the wheels. 10 OD drilled steel rotors were custom laser cut and used to transfer braking power from the calipers to the front wheels. 10 rotors will provide the greatest contact surface area while still fitting within our 13 wheels. The rear brake rotor was custom designed to double as a differential sprocket. It was designed and cut out of high strength stainless steel using a water jet machine at G.A. Industries. Figure 23: Cross-drilled & slotted brake rotor Brake Lines & Proportioning Valve Stainless Steel brake lines were used to deliver hydraulic pressure from the pedal mounted master brake cylinder to the P34 calipers mounted front and rear on the car. An adjustable proportioning valve will be installed to balance the front and rear caliper pressure. 22

29 11.0 WHEELS AND TIRES Wheels Our wheels will be 13x8 Toms Racing Igeta wheels made out of magnesium. They aid in minimal overall weight of the car with each wheel and tire assembly weighing only 22lbs. Another reason for choosing these wheels is the fact that they have a 4-bolt pattern and allow us to easily find an aftermarket hub that will fit them. Our decision was between these wheels and another 13 centerlock wheel but due to the time constraints of the project we would not be able to custom design a centerlock hub for those wheels. The figure shows a SolidWorks model of the wheel without the tire. Figure 24: SolidWorks rendering and photo of SF-1 rims for rain tires Tires The tires we will use for testing on local tracks will be Sumitomo performance low profile rain tires. Due to the weather in the lower mainland the majority of our test drives will be done in wet conditions and these will be the perfect tires until more serious pre-competition preparation begins. At that point we will swap the current tires over to Hoosier 20.0x or Goodyear 20.0x dry slicks for maximum traction in dry conditions found at the American tracks. 23

30 12.0 CHASSIS 12.1 Design & Stress Analysis Arguably the single most important part of the car, the chassis ties all of the separate subsystems together into a fully functioning race car. Our team considered three major designs for the chassis: steel space frame, aluminium space frame, and aluminium monocoque. In the end, a hybrid was designed combining features of an aluminum space frame with that of an aluminum monocoque. To set ourselves apart from the rest of the competition we have chosen to fabricate our chassis out of 6061-T6 Aluminum. Aluminum was the material of choice for its lightweight characteristics and its weldability. The weight of the chassis is approximately 50 lbs, about 25% lighter than traditional steel space-frames similarly seen in competitions. Unfortunately this choice had its drawbacks; the strength of aluminum is significantly less than that of chromoly or even mild steel. To counteract this 6061-T6 Aluminum alloy was selected. The 6061 is an alloy typically used is the aerospace industry, the T-6 heat treatment designation is the highest available and gave an ultimate strength of 300 MPa. Provisions have been put in place to have the chassis heat treated at Van Heat to the T-6 strength after all of the welding and fabrication is complete, this will realign the ions in the material and in turn increasing the overall strength of the chassis. The chassis changed substantially over the first 6 months of the capstone. The amount of time spent on chassis design was so long because it was an iterative process. In order to ensure all of the components will fit, all of those components themselves had to be modelled. To start with, a basis chassis design had to be adopted while other components were finished. A preliminary chassis rendering can be seen below in Figure

31 Figure 25: Preliminary Chassis Rendering - March In order to meet strict safety requirements while encouraging innovative design, FSAE allows alternative frame construction using unique materials and non-traditional fabrication techniques. To meet these safety standards, a Structural Requirements Certification Form (SRCF) must still be completed. After the final chassis geometry was determined, Finite Element Analysis (FEA) will be used to further evaluate the structural equivalency of the design. Due to the intense geometry of the structure and many hours of troubleshooting we gave up on using ANSYS Workbench and APDL software. We followed some SolidWorks Tutorials on Youbtube specific to FSAE chassis design and quickly found it was much more efficient to perform the analysis in SolidWorks using the included simulation package. 25

32 Figure 26: FEA Analysis on the Chassis in SolidWorks After FEA Analysis and all of the other major system components were modeled the chassis design was able to be finalized. As seen below, the chassis assembly is made of 3 major sections, the main chassis which encloses the driver and extends from the front bulkhead (the plate at the front) to the main roll hoop. The rear subframe is the boxed section rear of the main roll hoop. The roll hoop itself must be made out of mild steel in order to comply with FSAE rules and will be a bolt on component. The reason for separating the chassis into separate parts is mainly due to the size restriction of Van Heat s furnaces. The separate rear subframe eases engine installation and removal. A noticeable feature of the final chassis is the updated side structure which flows air to the dual rear mounted radiators as well as provides structural support for them. The flat panels and sharp contours were designed with sheetmetal fabrication in mind and give the car a stealth fighter look adding to the aesthetic appeal and originality. 26

33 Figure 27: Finalized Chassis Design 12.2 Chassis Fabrication Chassis fabrication started at the end of June and is almost complete to date with the exception of suspension control arm mounts and radiator supports. The following photos in this section show fabrication as of mid-july at the MRX Marine shop. The chassis fabrication consisted of cutting the material to length, grinding and notching the material to fit, and finally welding the different sections together T6 Aluminum was ordered prior to fabrication in stock 20 lengths. The majority of the chassis is constructed of round cornered square 1.5 or 1 cross section with wall thicknesses. 27

34 Figure 28: Chassis under construction in a Jig Figure 29: Welding the Chassis To create the complex geometry that makes up the chassis, key components were constructed individually using jigs. Jigs are fixtures that constrain the material from moving while welding is performed. Once the welding on the component was finished and the material had cooled it was removed from the jig and placed in a new jig prior to more welding. Piece by piece the chassis 28

35 was constructed until all of the main tubes were in placed. Trusses we re cut after this and welded in place to support the main structural beams of the chassis. Figure 30: Chassis nearing completion - July

36 13.0 KEY TECHNOLOGIES, AND SAFETY & OTHER FEATURES 13.1 Safety Integration Roll Hoop Requirements Since FSAE is a racing competition, it is crucial that driver safety be taken into consideration by the team. The SAE rulebook has a very firm set of rules regarding this area and design of the vehicle will be done around these key criteria. Figure 31: Minimum roll hoop clearance The chassis was designed to enclose the driver s body so that their head and hands will not contact the ground in any rollover attitude, according to FSAE rules. The same rules dictate that the cockpit must fit a 95 th percentile male; the SF-1 car allows for drivers up to 6 8 tall, with 2 helmet clearance under the main roll hoop. A 6 point safety harness featuring a single quick release latch will be used to restrain the driver to the vehicle in case of a collision. A head restraint will also be installed to limit the rearward motion of the driver s head and padded with an energy absorbing material. Aluminum sheet metal will be installed to separate the driver from all components of the fuel supply, engine oil and cooling systems. The aluminum will make up the non-permeable surface made that must be rigid and made out of fire resistant material. Additional isolation will be installed to protect the driver from any contact with material that may become heated to temperatures exceeding 60 o C Impact Attenuator To ensure driver safety on the front of the vehicle the chassis was designed to accommodate an impact attenuator, this is just one more safety feature required by FSAE to compete. We plan to order to order an FSAE standard impact attenuator type 10, 11 or 12, which costs roughly $

37 Jacking Point After the car is closer to completion, a jacking point will be fabricated out of aluminum and mounted to the rear of the vehicle to allow quick access to the underside of the vehicle by maintenance crews or judges. The jacking point will be designed as is later on. It will be painted orange for high visibility in all situations Key Technologies A certain level of technological advancement is expected in motorsports. Indeed, the sport is a showcase for some of the great developments that trickle down to consumer automotive fields. Below is a short list of some of the high-tech features of the First-Generation SF-1 offering: Lithium Ion Battery Relatively new to powersports, Lithium Ion technology is making leaps and bounds in the industry. Our use of this technology over Lead-Acid means to an instant weight savings of 9 lbs Skinned Space Frame Chassis A concept that is similar to a monocoque but incorporates the ease of tubular chassis fabrication with the additional rigidity and lighter weight afforded by integrated body panels LCD Display with Data logging Capabilities The Racer s Edge LCD dashboard and data logging system is a main selling point for the SF-1 team s technical expertise. A standalone system used for logging performance figures, this masterpiece of engineering is a bespoke design by the SF-1 Electronics division. It is used during races and test runs for the purpose of holistic vehicle tuning, allowing the driver and pit crew to squeeze the last ounce of performance from every lap. Similar systems exist on the market and are being used by competing race teams. However, these systems frequently cost upwards of $4000 and offer limited customizability. The SF-1 system, on the other hand, is a student-designed system, resulting in a net cost to SF-1 of under $500, and is easily customizable by members of our capstone team. 31

38 For more details of the LCD display and Datalogger, please refer to the appropriate documentation from the SF-1 Electronics Division Limited Slip Differential Limited Slip Differential technology offers increased traction to both drive wheels and allows the use of advanced braking systems in the rear. The SF-1 differential uses internals from Torsen, Inc. and a custom-machined aluminium housing to save weight. 32

39 14.0 CONCLUSION Thus far we have achieved many of our goals and accomplished many of the deliverables we intended on showcasing by the end of our Capstone project. We like to believe that we have started a long lasting legacy for SF-1 and its team members in the university racing industry. At this point we are at the final stages of vehicle assembly as the bulk of the design work has been finalized. The major components of the car (chassis, drivetrain, suspension and steering/brakes) have been fabricated or are in the process currently. Seeing as this is a school club as well as a capstone project several of the team members will continue to work on the vehicle while also transitioning into a new executive team. Competition in 2014 is within grasp and we hope that the majority of the team members will be able to attend. In addition, by building strong relationships with industry partners we have ensured that the donations and discounts will be ongoing and transferrable into future years. We expect more sponsors to be acquired as exposure of the team increases through events such as the Vancouver International Auto show and others. Our goals consist of having a completed prototype by October 2013, a car with over 90% of the final components assembled and the car being drivable. Furthermore, we are currently working with the Dean of Engineering and SFU in acquiring some designated shop space for SF-1 along with other engineering teams here at SFU. We hope that when we transition the team to its new members (mid-late September) we will have designated shop and storage space. Our options currently are between the old Shell Service station on SFU Burnaby and off-site warehouse rental space in a location between the Burnaby and Surrey campuses. 33

40 15.0 REFERENCES Corporate Author: SF-1 Engineering: SF-1 Electrical: Design Specification for The Racer s Edge. Corporate Author: SF-1 Engineering: SF-1 Mechanical: Design Specification For SFU s First Formula SAE Race Car. Course Requirements: Simon Fraser University, MSE400. Corporate Author: SF-1 Engineering: SF-1 Mechanical: Functional Specification For SFU s First Formula SAE Race Car. Course Requirements: Simon Fraser University, MSE400. Corporate Author: SF-1 Engineering: SF-1 Mechanical: Updated Business Proposal. Course Requirements: Simon Fraser University, MSE400. Corporate Authors: SF-1 Engineering et al. : Storage & Workspace Proposal for SFU Engineering Teams. MotoIQ.com. 24 August Website: Formula SAE: What a Few Car College Gear Heads Can Do In Their Free Time. < 2072/pageid/3483/formula-sae- what-a-few-car-college-gear-heads-can-do-in-their-freetime.aspx> MotoIQ.com. 24 August Website: Formula SAE: What a Few Car College Gear Heads Can Do In Their Free Time. < 2072/pageid/3483/formula-sae- what-a-few-car-college-gear-heads-can-do-in-their-freetime.aspx> Mott, Robert L. (2004). Machine Elements in Mechanical Design 4 th Edition. Slocum, Jonathan M. MIT FSAE Racer. (Powerpoint Presentation). <web.mit.edu/jtslocum/ www/documents/fsae/steering.pdf> Society of Automotive Engineers. 22 November, FSAE 2013 Rules. Summit Racing Equipment, Inc. (Online Catalogue). < Summit Racing Equipment, Inc. (Online Catalogue). < Wilwood Performance Brakes. (Manufacturer s Data). < Woodward Steering, Inc. (Online Catalogue). < Woodward Steering, Inc. (Online Catalogue). < 34

41 MotoIQ.com. 24 August Website: Formula SAE: What a Few Car College Gear Heads Can Do In Their Free Time. < 2072/pageid/3483/formula-sae- what-a-few-car-college-gear-heads-can-do-in-their-freetime.aspx> Woodward Steering, Inc. (Online Catalogue). < Summit Racing Equipment, Inc. (Online Catalogue). < Slocum, Jonathan M. MIT FSAE Racer. (Powerpoint Presentation). <web.mit.edu/jtslocum/ www/documents/fsae/steering.pdf> Wilwood Performance Brakes. (Manufacturer s Data). < Society of Automotive Engineers. 22 November, FSAE 2013 Rules. Mott, Robert L. (2004). Machine Elements in Mechanical Design 4 th Edition. Corporate Authors: SF-1 Engineering et al. : Storage & Workspace Proposal for SFU Engineering Teams. Corporate Author: SF-1 Engineering: SF-1 Mechanical: Updated Business Proposal. Course Requirements: Simon Fraser University, MSE400. Corporate Author: SF-1 Engineering: SF-1 Electrical: Design Specification for The Racer s Edge. Corporate Author: SF-1 Engineering: SF-1 Mechanical: Design Specification For SFU s First Formula SAE Race Car. Course Requirements: Simon Fraser University, MSE400. Corporate Author: SF-1 Engineering: SF-1 Mechanical: Functional Specification For SFU s First Formula SAE Race Car. Course Requirements: Simon Fraser University, MSE

42 APPENDIX A: SAMPLE SPONSORSHIP PACKAGE (CIRCULATED TO POTENTIAL SPONSORS) The following is a formal breakdown of what your company receives for its contribution. Sponsorship benefits are based on the monetary value contributed whether it is in the form of a financial donation or a service rendered. TITLE SPONSOR: $3500 and above Benefits include a company specific paint scheme and a large logo in a preferred area of the vehicle. Your company name and logo will also be displayed on the team website, team merchandise as well as at events. GOLD SPONSOR: $ $3500 Benefits include a 48 in2 logo on the vehicle. Your company name and logo will also be displayed on the team website, team merchandise and at events. SILVER SPONSOR: $750 - $1500 Benefits include a 24 in2 logo on the vehicle. Your company name and logo will also be displayed on the team website, team merchandise and at events. BRONZE SPONSOR: $100 - $750 Benefits include a 12 in2 logo on the vehicle. Your company name and logo will also be displayed on the team website and at events. PARTNER SPONSOR: $50 - $100 Perfectly suited for individuals who want to contribute but are unable to provide a larger amount. Benefits include your name displayed on the vehicle, team website and at events. Current Sponsors Gold Sponsors MRX Marine Engineering Undergraduate Student Society Endowment Fund Silver Sponsors Sea Star Solutions SFU Faculty of Applied Science SFU School of Engineering Science 36

43 Bronze Sponsors SolidWorks Association of Professional Engineers & Geoscientists BC (APEG BC) Simon Fraser Student Society Battery World Lordco Automotive QS Components Maple Ridge Motorsports Knight Hill Automotive Partner Sponsors - Allied Threaded Products Fasteel Industries Samuel Metal Distributors 37

44 APPENDIX B: BILL OF MATERIALS 38

45 39

46 APPENDIX C: SUSPENSION SolidWorks sketches for solving & checking geometry Sample sketch used to solve front suspension geometry Sample Sketch used to solve rear suspension geometry 40

47 Sample sketch used to check bell crank dimensions 41

48 Sample spreadsheet for calculating bell crank & pushrod ratios 42

49 Sample Suspension Stress Analysis SolidWorks Flow Analysis FEA on Front Lower Control Arm, showing Von Mises stresses 43