2014 Bearcats Baja

A Baccalaureate thesis submitted to the

Department of Mechanical and Materials

Engineering

College of Engineering and Applied Science

University of Cincinnati

In partial fulfillment of the Requirements for the degree of

Bachelor of Science

In Mechanical Engineering Technology

By:

Zack Freije

April 2014

Thesis Advisor:

Dean Allen Arthur

Rear Suspension System

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2014 Bearcats Baja – Rear Suspension System

Zack Freije Rear Suspension

Copyright © 2007 SAE International

ABSTRACT

Baja SAE is an annual intercollegiate engineering design competition organized by the Society of Automotive Engineers, and serves as a capstone project for senior Mechanical Engineering Technology students at the University of Cincinnati. The 2014 Bearcats Baja team vehicle is a complete new build from the ground up. This design freedom allows for drastic improvements over the 2013 rear suspension system performance. Extensive research was conducted to determine the key performance metrics for the system. Several design options were considered and a final design was selected based on system integration, manufacturability, system weight, cost, and design specifications required to meet the performance metrics. Failure modes were established based on 2013 in-use performance results. FEA optimization was performed side by side with the 2013 system to establish a baseline for improved stress handling while optimizing weight. The final design was produced with a 22% cost savings, 7% weight reduction, and was verified to within 0.5° for toe/camber angle and

within 1/16” for all setting dimensions relative to

established design specifications.

INTRODUCTION

Baja SAE is an annual intercollegiate engineering design competition run by the Society of Automotive Engineers (SAE). Teams of students from Universities around the world design and build small off-road vehicles powered

by engines with identical specifications.

All teams must adhere to the rules and pass SAE’s technical and safety inspections. At each competition there are design evaluations and multiple dynamic events followed by a four-hour endurance race. Dynamic events for 2014 include maneuverability, rock crawl, and suspension & tracking. The endurance race carries the single largest point total. These events require a

suspension that is agile as well as robust.

Furthermore, each team is competing to have its design selected by a theoretical power sports manufacturing company with the stated intent of a 4,000 unit annual production volume. Each team is responsible for all phases of the research and development process, from fundraising to designing, manufacturing and testing.

Each vehicle is evaluated in terms of ergonomics, functionality, and producibility. To this end, design reports must demonstrate both sound engineering principles as well as economic feasibility for production.

An off-road vehicle’s suspension system serves three primary functions: to maintain tire contact with the ground while the vehicle navigates rough terrain, to reduce impact forces transferred to the driver, and to

provide optimal vehicle handling dynamics. (1)

RESEARCH

Full compliance with all relevant Baja SAE rules is required. The applicable rules have been supplied in

Appendix B. (2)

A list of reference material used for concept and

application of design are given in Additional Sources.

Great attention was placed on the design and performance of the 2013 rear suspension system during competition. In addition, a careful survey of design choices was conducted for all the top 10 teams during competition in 2013. Time was spent discussing the merits of these choices with the competing teams to gain

a better understanding of the engineering justification.

Five primary design choices were identified for further

study:

Single rear inboard brake – eliminates need for

heavy bearing carrier to support caliper, reduces

total vehicle weight.

Trailing arm integrated bearing carrier – a simple

and lightweight bearing carrier can be welding into the trailing arm to reduce weight, complexity and

hardware.

Custom aluminum wheel hub – a simple and

lightweight hub can be manufactured for custom backspacing. Can eliminate rotor mounting bosses

and hardware.

Narrow rear chassis/Longer control arms –

Reduce length of heavy frame tubes. Increase

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length of lateral links to provide better control over

camber change rate.

Minimize size of heim joints/Mount in double shear – Heim joints can be reduced in size if proper

calculations are made to determine the worst case forces. Mount them in double shear to reduce

bending moment on the threads.

Example pictures for these design cues are given in

Appendix C.

The primary levers for improving rear suspension

performance are:

Toe Settings

Camber Settings

Pitch Settings

Roll Axis

TOE SETTINGS

Figure 1 – Toe Conditions

Positive toe is preferred. For a rear wheel drive car, rear toe-out leads to overseer which promotes a faster maneuverability response. Static toe or no change in toe angle over the suspension travel is preferred. Dynamic

or changing toe leads to bump steer.

CAMBER SETTINGS

Figure 2 – Camber Conditions

Negative camber is preferred. Negative camber leads to straight line stability. Static camber or no change in

camber angle over the suspension travel is preferred.

PITCH SETTINGS

Figure 3 – Pitch Conditions

20-30% antisquat is preferred. This increases the normal force at the tires and improves acceleration. Antisquat also increases suspension stiffness, producing jacking forces similar to an anti-roll bar without reducing body

roll.

ROLL AXIS

Figure 4 – Roll Center Height

Low roll center height is ideal as this leads to lateral acceleration weight transfer via body roll. Roll center axis ideally slopes down towards the front of the vehicle which allows for weight transfer to the front of the vehicle during a turn. This allows more grip on the steering tires and allows the rear end to break free and slide which

creates oversteer.

DESIGN SELECTION - Early design concepts that were rejected include: dual a-arm, torsion bar, inboard shock, single tube trailing arm, toe control link. It was observed at competition that failure of any part of a dual a-arm setup would result in disengagement of the drive axle, rendering the vehicle immobile and costing valuable time being towed into the pits. The 2013 Bearcats vehicle sustained complete failure to one of the lateral links during an endurance race, but was able to complete a lap and drive into the pits under its own power. It was determined that torsion bars add weight and complexity and attempt to correct for problems with the initial suspension design. Toe control links added weight and complexity, but were unnecessary because the suspension could be designed such that optimal toe was achieved without them. The single tube trailing arm was a lead option until it was determined that SAE chassis rules made the desired mounting location impossible. It was also considered that a single tube would have

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greater potential to fail due to buckling after impacting stationary objects on course.

The selected design incorporates a semi-trailing arm and a pair of lateral links. This is similar to the suspension used on an Integra Type R. This is the third year Bearcats Baja has used and improved this general

design.

Figure 5 – Selected Design

Figure 6 – Axle Section View

DESIGN GOALS

PRIMARY OBJECTIVES

Improve handling response*

Reduce Weight

Reduce Cost

*Handling Response - Dynamic handling is subjective, and prior to testing, is largely theoretical with respect to design. Each driver will have a handling preference and each overall vehicle will respond differently to the same design. Course design and conditions also play a factor. Holistic handling response takes into account the interaction between the front and rear suspension

designs.

DESIGN SPECIFICATIONS - The following constitutes a complete list of the selected design specifications to achieve with this rear suspension system design.

Vertical Wheel Travel: 10.6” (269.2mm)

Recessional Wheel Travel: 0.5” (12.7mm)

Static Ground Clearance: 11” (279.4mm)

Jounce Ground Clearance: 4” (101.6mm)

Static Roll Center: 8” (203.2mm)

Motion Ratio: 0.5

Sag: 33% of total travel

Total Track Change: 4” (101.6mm)

Track Change in Roll: 0” (0mm)

Static Toe: 0 deg

Toe Change Rate: 0.5 deg/in

Static Camber: -0.5 deg

Camber Change Rate: 0.25 deg/in

Percent Anti Squat: 20%-30%

System Weight: 50 lbs (22.7 kg)

SYSTEM INTEGRATION – To accomplish the design specifications, both system integration and rules compliance were key factors. System integration required collaboration with braking, drivetrain, chassis, and front suspension systems. To reduce the weight for the rear suspension, the brakes were moved inboard, allowing for elimination of the purchased bearing carrier. A new custom bearing carrier was integrated into the trailing link. The Rear Roll Hoop was lengthened, lowering the drivetrain and vehicle CG, and optimizing the angle of the axles for increased power transfer and reduced plunge travel. In addition, the Rear Roll Hoop was made laterally narrow rearward of the gearbox to allow for longer trailing links which provide the desired camber change rate. Initial design concepts for trailing link geometry and mounting locations were rejected due to

rules compliance for the Roll Hoop.

WEIGHT - The wheels and tires represent 61% of the total system weight. However, weight was increased by 2% over last year for reliability. Previously, Douglas Blue Label (0.125” wall) were used, however all were bent during normal use. To improve this, ITP T9 Pro (0.190” wall) were selected which are considerably stronger and weigh 0.38 lbs more per corner. The same lightweight 23x7-10 Carlisle 489 tires were selected due to their performance at competition. Selecting a stiffer wheel will mitigate the negative impact of the 2-ply tire. A reduction of 4 lbs (7% of total system weight) was achieved by replacing the Polaris Sportsman 300 bearing carrier with a custom carrier that was integrated into the trailing link. The new bearing carrier was designed around a Honda TRX420 which allowed for additional weight reduction of related components. This

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also allowed us to install inboard and outboard dust seals in order to improve the life of the bearings. Custom aluminum wheel hubs were designed which provided a potential 4.5 lbs (8% of total system weight) reduction, however, Honda TRX420 hubs were purchased due to funding and manufacturing capability shortfalls related to broaching the internal spline. This resulted in a 1.17 lb increase in weight. Additional weight reduction was achieved through calculations and FEA to optimize weight and strength simultaneously. In addition, all mounting brackets and hardware was sized and weight minimized using FEA and hand calculations. Total weight for the system is 53

lbs, meaning a reduction of 4 lbs or 7% was achieved.

DESIGN OPTIMIZATION - In order to meet the design specifications, a SolidWorks 3D dynamic sketch was used. Sensors were placed on key components in order to quantify the impact of geometry or dimensional changes. Outputs include: wheel travel, ground clearance, track change, motion ratio, toe, camber, roll center and axle plunge depth. The final solid model was moved through the same range to verify the predicted

outputs.

Figure 7 – 3D Design Optimization Sketch

Figure 8 – Design Optimization Solid Model

In order to optimize the tube size and wall thickness, two graphs were used: C/I vs. Weight and Stress/Unit Length vs. Linear Weight (shown in the figures below). The lead options were then tested in various combinations in FEA to achieve a desirable safety factor for the worst case loading conditions. The three primary failure modes considered for the trailing arms are: 5’ vertical drop (2 wheel landing), forward impact to an obstacle (tree or vehicle) at the vehicle top speed of 32mph, and a vertical drop, landing directly on the trailing arm tubes. The lateral links were optimized in FEA for a full speed direct impact collision from another vehicle to simulate the failure mode experienced in the endurance

competition last year.

Figure 9 – Material Optimization

Figure 10 – Material Optimization

Lower unit weight is desired as is a lower C/I value.

The material selected is AISI 4130 steel, stress relieved after welding and normalized to achieve a yield strength of 96 ksi. (3) For manufacturability, trailing arm tubes all have the same 1” OD. The lower members were FEA optimized to have a larger wall thickness (0.049”) for greater strength as needed due to direct impact with obstacles. This represents a 15% weight improvement per unit length over the 2013 design and a 17% lower C/I value. The remaining tubes have a wall thickness of 0.035”. This represents a 38% improvement for weight and a 62% lower C/I value. The trailing arms are

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designed to a safety factor of 1.9. The lateral links were FEA optimized to 0.875” OD and 0.049” wall. The lateral

links are designed to a safety factor of 1.4.

All suspension pivot points were designed for less than 0.5° of misalignment, however, modest misalignment

spacers were used to improve both manufacturability and serviceability. Lateral Links have opposing LH and RH heim joints with threaded inserts and jam nuts that allow for camber adjustment. The opposing thread types prevent the system from self-adjusting during use due to vibration. The heim joints are mounted in all cases in

double shear with a bending safety factor of 1.9.

All failure mode conditions were replicated using last year’s models for a direct delta comparison of max stress and stress concentration. In all cases, the new design is equal or better in handling stress as compared

to last year.

The hardware is kept a consistent size for serviceability, and is designed to a safety factor of 4.8, calculated using

the worst case resultant force found using FEA.

Figure 11 – Two Wheel Vertical Drop, Five Foot Elevation

Figure 12 – Forward Impact to Stationary Object

Figure 13 – Vertical Drop to Stationary Object

Figure 14 – Rear Impact to Lateral Link, Worst Case Position

Figure 15 – Progressive Air Spring Curve

At 5.5 inches of travel, the air spring requires 1400 lbf (when inner air pressure is set to 70 psi) in order to achieve full compression. This reaction force was applied to the shock mount bracket with the trailing arm fixed in place. This did not produce the worst case scenario for stress response in FEA.

Vehicle crash data was reviewed to establish a reasonable g-force at impact. An average value of 5 g was used to calculate the impact force. (4)

1,700 lbf

2,700 lbf

1,700 lbf

3,000 lbf

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Figure 16 – Impact Force Test Data

2 Wheel Vertical Drop (5 feet) – Initial calculations were performed assuming conservation of energy and using work and energy equations, given the available travel of the dampers. Forward momentum was neglected and only vertical components were considered. This was compared to the impact force calculated using the 5 g deceleration from the crash test data. The largest impact

force was used for FEA.

Forward Impact to Stationary Object – Initial calculations considered time of impact, however, no reliable testing data exists to validate this approach, so crash test data was used instead. This is to simulate hitting another vehicle or a stationary object such as a tree. The crash

test data average of 5 g was used for this calculation.

Vertical Drop to Stationary Object – This is to simulate hitting a log or rock with a sharp edge. The surface area the force is applied to is 1/8” wide. The same 1,700 lbf is used as in the 2 wheel drop scenario.

Rod End Bending – Rod ends are most likely to fail in bending in the threaded region. To properly size a rod end, it is required to have an allowable load greater than 10 times the axial load. The worst case resultant force component on the control arm rod end is 811lbf. Based on this calculation, the 5/16” shank rod end is selected,

with a safety factor of 1.9. (6)

(6)

Bolt Shear Calculations – All system bolts were sized based on shear strength calculations given the worst case loading condition resultant force. Double shear mounting condition is used in all locations. Grade 8 hardware is used in all locations with nylon locking nuts.

5/16” bolts selected provide a safety factor of 4.8.

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Figure 17 – Double Shear

Figure 18 – Bolt Strength Formulas (7)

Antisquat Calculations

Figure 19 – Antisquat Geometry

Figure 20 – Antisquat Geometry

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Roll Center Height and Roll Axis

Figure 21 – Rear View Roll Center Height

Figure 22 – Side View Roll Center Height

The roll center height was successfully reduced and adjusted to work effectively with the front suspension for

better overall vehicle dynamics.

MANUFACTURABILITY – A simple and flexible weld jig was designed and fabricated for the trailing arms using off the shelf aluminum structural framing components combined with machined bosses to position key components and act as heat sink. Tubes were bent and partially coped by Cartesian. (5) The remaining trimming and coping at assembly was performed in house using a

custom alignment jig.

Figure 23 – Flexible Trailing Arm Fixture Design

Figure 24 – Trailing Arm Assembly Fixture and Weld Jig

Figure 25 – Control Arm Mounting Bracket Attachment

The jig was made from available spare extruded aluminum t-slot. Fixturing attachments were designed and fabricated in the shop. It allows for both RH and LH assemblies to be assembled, and has attachments for every step in the manufacturing process.

Figure 26 – Setting Up for Bearing Carrier Tube Cope

Figure 27 – Custom Tube Inserts to Allow Clamping

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Custom tube inserts were machined to prevent deforming the trailing arm tubes while clamped in place. They were tapped and a bolt inserted in the event they would be difficult to remove. An alignment jig was made to provide accurate hole cutting position. An overhead drill press on low speed with sufficient cutting oil was used to perform the necessary cope in the trailing arm tubes. Subsequent fitting of the bearing carrier was

problem free, with a modest 0.5mm gap on either side.

Figure 28 – Bearing Carrier Fitment

All shock and control arm mounting brackets were pre-assembled from plasma cut 4130 1/16” steel sheet using custom weld jigs to position the tube alignment reliefs. Frame mounting brackets followed the same process, each with a unique custom machined jig to hold the bolt centers in-line and position the bolt axis relative to the bottom of the vehicle. The pre-assembled shock mount brackets with tube copes are easily placed on the tubes limiting them to two degrees of freedom. Additional jigs were used to position the trailing arms according to the SolidWorks design and align the shock mounting

brackets to reduce the need for misalignment spacers.

Figure 29 – Frame Mounting Bracket

Figure 30 – Shock Mounting Bracket

Figure 31 – Control Arms

RESULTS

DESIGN SPECIFICATIONS ACHIEVED

Vertical Wheel Travel: 10.6” (269.2mm)

Recessional Wheel Travel: 0.4” (10.2mm)

Static Ground Clearance: 11” (279.4mm)

Jounce Ground Clearance: 4” (101.6mm)

Static Roll Center: 6.5” (165.1mm)

Motion Ratio: 0.5

Sag: 33% of total travel

Total Track Change: 3.8” (96.5mm)

Track Change in Roll: 0” (0mm)

Static Toe: +0.76 deg

Toe Change Rate: 0.27 deg/in (0.01 for 95% of use)

Static Camber: -0.6 deg

Camber Change Rate: 0.1 deg/in

Percent Anti Squat: 26%

System Weight: 53 lbs (24 kg)

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Figure 32 – Validation and Testing of Design

Specifications

SYSTEM WEIGHT

2013 components weighed back to back with 2014 components on the same scale multiple times, with the median values being used for comparison.

SYSTEM COST

(2 complete sets, plus spares)

The cost was reduced by designing for the elimination of components where possible and to fabricate parts rather than purchase them. Parts and material were reused where applicable. Material sponsorship was negotiated as were pricing discounts for purchased components. The requirement for material was also reduced by this

design.

CONCLUSION

The selected rear suspension system design was able to deliver on all the design specifications. The system provided both cost and weight savings. The suspension design was able to deliver these results while outperforming the 2013 design in the failure modes determined by competition performance. The design

incorporated consideration for ease of manufacturing, assembly and use. The manufacturing and assembly process went smoothly and the low-cost, flexible jig was able to deliver the required dimensional accuracy for designed suspension performance. After assembly to the vehicle, the suspension met all of the design specifications within an exceptional margin of error. There are additional design improvements and weight savings that were unfeasible for this design iteration, but are described in the Recommendations section. Vehicle dynamic performance at competition will provide additional data points for ongoing design optimization to

improve future vehicle executions.

RECOMMENDATIONS

The easiest way to reduce weight and provide design flexibility for the rear suspension system is to make custom aluminum hubs. The COTS hubs used account for 11% of the total system weight. Material can be provided through sponsorship; however, machining capability is a challenge to be overcome. The greatest challenge will be in broaching the necessary internal spline. These will need to be adequately tested prior to competition to validate the FEA results. Consider a secondary COTS option in case testing does not validate the design.

Figure 33 – 2014 Honda Hub

Figure 34 – New Hub Design Concept

With more investment in fixturing, dimensional accuracy could be improved to the point that some of the heim joints could be removed in favor of a Delrin or polyurethane bushing. This will provide additional weight

savings.

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The rear semi-trailing arm design can be further optimized for weight by converting to a single tube arm. 1.25” diameter, 0.049” thick wall should be sufficient for the given loading conditions. The forward mounting location to the frame should be changed to a heim joint and mounted in a configuration to allow for the single tube design. This may require a custom hub offset or

custom wheel offset to ensure the shock clears the tire.

There is significant weight in the wheels and tires. There is additional work to be done to fully test a wide array of combinations (including air pressure) to optimize for all anticipated course conditions while reducing weight. This requires time investment after the vehicle is complete and represents a substantial financial investment as well. I recommend either: 1. Douglas Blue Label (0.125” wall) combined with a 4 or 6 ply tire and sufficient air pressure, or 2. Douglas Black Label (0.160” wall) combined with a 2 ply tire such as the Carlisle 489. Keep in mind that there are course conditions in which low tire

pressure provide greater traction.

ACKNOWLEDGMENTS

Thanks are due to the University of Cincinnati for their enduring support of the Bearcats SAE program. In addition, the MET program provided a strong basis for success in this project due to the inherent combination of theoretical and applied science. The faculty has been most gracious with their time and expertise in supporting our efforts. Most notably our faculty advisor: Dean Allen

Arthur.

Thanks are also due to our generous corporate sponsors, without whom we would not have been able to finance the project. These include: Toyota, Gallatin Steel, Kaiser Aluminum, Solidworks Corp., VR3 Engineering, Polaris, Cincinnati Gearing Systems, Cincinnati Steel Treating, Honda of Fairfield, Wilwood, General Cable, Dana, Grainger, and Discount Tire.

REFERENCES

1. "Baja SAE." Wikipedia. Wikimedia Foundation, 18

Mar. 2014. Web. 22 Apr. 2014.

2. "2014_baja_rules_8-2103." Rules & Documents.

SAE Collegiate Design Series, 2014. Web. 22 Apr.

2014.

3. "AISI 4130 Steel, Normalized at 870°C." ASM

Material Data Sheet. N.p., n.d. Web. 23 Apr. 2014.

4. Linder, Astrid, and Matthew Avery. "CHANGE OF

VELOCITY AND PULSE CHARACTERISTICS IN

REAR IMPACTS: REAL WORLD AND VEHICLE

TESTS DATA." National Highway Traffic Safety

Administration. The Motor Insurance Repair

Research Centre, n.d. Web. 22 Apr. 2014.

5. "Cartesian Tube Profiling - Impossibly Accurate

Tube Profiling." Cartesian Tube Profiling. N.p., n.d.

Web. 23 Apr. 2014.

6. "FK Rod Ends- Home Page." FK Rod Ends- Home

Page. N.p., n.d. Web. 23 Apr. 2014.

7. "Fastener, Bolt and Screw Design Torque and Force

Calculation - Engineers Edge." Fastener, Bolt and

Screw Design Torque and Force Calculation -

Engineers Edge. Engineers Edge, n.d. Web. 23 Apr.

2014.

CONTACT

Zack Freije

Rear Suspension

freijezy@mail.uc.edu

ADDITIONAL SOURCES

Aird, Forbes. Race Car Chassis: Design and Construction. Osceola, WI: Motor International, 1997. Print.

"BajaSAE Forums." BajaSAE Forums. N.p., n.d. Web. 22 Apr. 2014.

Dixon, John C. Suspension Geometry and Computation. Chichester, U.K.: Wiley, 2009. Print.

Gillespie, T. D. Fundamentals of Vehicle Dynamics. Warrendale, PA: Society of Automotive Engineers, 1992. Print.

Milliken, William F., and Douglas L. Milliken. Race Car Vehicle Dynamics. Warrendale, PA, U.S.A.: SAE International, 1995. Print.

Smith, Carroll. Engineer to Win. Osceola, WI: Motor International, 1984. Print.

Staniforth, Allan. Competition Car Suspension: Design, Construction, Tuning. Newbury Park, CA: Haynes North America, 1999. Print.

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APPENDIX A

DEFINITIONS, ACRONYMS, ABBREVIATIONS

SAE: Society of Automotive Engineers

MET: Mechanical Engineering Technology

Track Width: Distance between the centerline of the

contact patches of the tires when looking at the vehicle in front view

Wheelbase: Distance between the centerline of the

contact patches of the tires when looking at the vehicle in side view

Toe Angle: The angle, positive or negative, of the wheel

from straight ahead. Toe to the outside of the vehicle is, by convention, positive and results in less stability

Camber Angle: The angle between the vertical axis of

the wheels the vertical axis of the vehicle when viewed from the front or rear

Bump Steer: Steering motion without driver input

resulting from the translation of the wheel and suspension through its swept arc as a reaction to bump loading

Roll Steer: Steering motion without driver input resulting

from the translation of the wheel and suspension through its swept arc as a reaction to the rolling of the vehicle while corning

Anti-Squat: This suspension characteristic uses

acceleration-induced forces in the rear suspension to

reduce squat of the vehicle. A value of 100% means that all of the weight transfer is being carried through

the suspension linkage, not the dampers

Shocks: Commonly referred to as a shock absorber,

and performs the function of a damper between the road input and the response of the vehicle

COTS: Commercial Off-The-Shelf

Roll center height: Found by projecting a line from the

center of the tire-ground contact patch through the front view instant center. [7]

Motion Ratio: The mechanical advantage (lever ratio) that the wheel has over the spring in compressing it

Heim Joint: Rod end bearing. A mechanical articulating

joint consisting of a ball swivel with an axial opening through which a bolt may pass which is pressed into a casing with a threaded shaft attached

Control Arms: A pair of lateral suspension links that are

adjustable in length to affect changes to camber and toe angle

CG: Center of gravity, specifically for the entire vehicle

and driver

‘: Foot

“: Inches

Lb: Pound

Lbf: Pound force

Lbm: Pound mass

Slugs: English unit of mass

FPS: Feet per second

MPH: Miles per hour

psi: Pounds per square Inch

ksi: Kips per square inch

Kip: 1000 pounds

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APPENDIX B

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APPENDIX C

COMPETITIVE RESEARCH

Rear inboard brake Integrated bearing carrier

Narrow chassis, long control arms

Narrow chassis, long control arms

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APPENDIX D

EXPENSES

Expense Tracking Spreadsheet (includes 2 full sets, plus spares)

Vehicle Budget Distribution

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APPENDIX E

WEIGHT

Weight Tracking Spreadsheet

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APPENDIX F

SCHEDULE

Overall Task Schedule

Example Detailed Task Schedule by Section

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APPENDIX G

REAR SUSPENSION ASSEMBLY DRAWINGS

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21

22

23

24

25

26

27

28

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APPENDIX H

FIXTURE DRAWINGS

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31

32

33

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