Formula 1Formula 1Group Members: Group Members:

Quinn CollettQuinn CollettSteve GodlewskiSteve Godlewski

Tobiah HalterTobiah HalterJeff SwansonJeff Swanson

Academic Advisor:Academic Advisor:Dr. Chien WernDr. Chien Wern

June 4, 2003June 4, 2003

IntroductionIntroduction

Formula SAE is a competition focused on Formula SAE is a competition focused on the design and fabrication of an the design and fabrication of an affordable, weekend racecar. affordable, weekend racecar. Performance and reliability are necessary Performance and reliability are necessary attributes. attributes.

As a Senior Project group we chose to As a Senior Project group we chose to design three major components of the design three major components of the car. car.

Project ScopeProject Scope

Design, fabrication and testing of the Design, fabrication and testing of the three design components:three design components: Hub AssembliesHub Assemblies DrivetrainDrivetrain AerodynamicsAerodynamics

Decision ProcessDecision Process

Product Design SpecificationsProduct Design Specifications External SearchExternal Search Internal SearchInternal Search Concept EvaluationConcept Evaluation

Presentation OutlinePresentation Outline Rear Hub and Upright DesignRear Hub and Upright Design Front Hub and Upright DesignFront Hub and Upright Design Differential Housing and Drivetrain Differential Housing and Drivetrain

DesignDesign Aerodynamics DesignAerodynamics Design

Rear Hub and Upright DesignRear Hub and Upright Design

ComponentsComponents Bearing Housing Bearing Housing FlangesFlanges Connection PointsConnection Points Angle BracketAngle Bracket Bearings Bearings FastenersFasteners

Analysis of HubAnalysis of Hub Material: 6061-T6 AluminumMaterial: 6061-T6 Aluminum Yield Strength: 40 ksiYield Strength: 40 ksi Factor of Safety: 3Factor of Safety: 3 Design Stress: 13.3 ksiDesign Stress: 13.3 ksi

Results of FEA Analysis:Results of FEA Analysis: Max Von Mises Stress: 14.5 ksiMax Von Mises Stress: 14.5 ksi Maximum Displacement: 0.002 inMaximum Displacement: 0.002 in

Analysis of Analysis of UprightUpright

Material: 6061-T6 AluminumMaterial: 6061-T6 Aluminum Yield Strength: 40 ksiYield Strength: 40 ksi Factor of Safety: 3Factor of Safety: 3 Design Stress: 13.3 ksiDesign Stress: 13.3 ksi

Results of FEA AnalysisResults of FEA Analysis Max stress: 16.3 ksiMax stress: 16.3 ksi Max Deflection: 0.004 inMax Deflection: 0.004 in

VerificationVerificationPDS CriteriaPDS Criteria WeightWeight: :

The hub assembly will weigh less than 17 lbs.The hub assembly will weigh less than 17 lbs. Hub=2.5 lb, Upright=4.5 lb, Total = 7 lbHub=2.5 lb, Upright=4.5 lb, Total = 7 lb

Size/shapeSize/shape: : Components will fit within an 13 inch wheel.Components will fit within an 13 inch wheel. It does fit.It does fit.

MaintenanceMaintenance: : 2 hour yearly overhaul2 hour yearly overhaul Maintenance free: sealed bearings, locktite on all screwsMaintenance free: sealed bearings, locktite on all screws

InstallationInstallation: : Install in less than 120 min.Install in less than 120 min. Can be done inside of an hour: press in bearings, 3 bolts per sideCan be done inside of an hour: press in bearings, 3 bolts per side

Cost Cost (materials, bearings, bolts): (materials, bearings, bolts): less than $400less than $400 Housing: $54.00, Hub: $186.94, Flange: $65.20, Connectors: $50.54, Housing: $54.00, Hub: $186.94, Flange: $65.20, Connectors: $50.54,

Angles: $1.34, Fasteners: $8.61, Bearings: $18.80Angles: $1.34, Fasteners: $8.61, Bearings: $18.80 Total Cost of Materials: $385.43Total Cost of Materials: $385.43

Dynamic TestingDynamic Testing Has performed properly to this pointHas performed properly to this point

Front Hub/UprightFront Hub/Upright Design CriteriaDesign Criteria

PDSPDS 30%-40% weight reduction over last years car30%-40% weight reduction over last years car Ideal weight of 14 lbs.Ideal weight of 14 lbs. Assembly fit within a 13 in. dia. WheelAssembly fit within a 13 in. dia. Wheel Handle loadings in race conditionsHandle loadings in race conditions Incorporate connecting points for suspension and steering Incorporate connecting points for suspension and steering

systemssystems

Component SelectionComponent Selection Suspension GeometrySuspension Geometry Steering PositioningSteering Positioning Brake ComponentsBrake Components Bearing SelectionBearing Selection

Front Hub/UprightFront Hub/Upright AnalysisAnalysis

CalculationsCalculations Track ConditionsTrack Conditions

Top speeds 60 mph/ Avg. Speed 30 mphTop speeds 60 mph/ Avg. Speed 30 mph Safety FactorsSafety Factors

Front Hub/UprightFront Hub/Upright ComponentsComponents

Hub assemblyHub assembly Two piece design for ease of Two piece design for ease of

maintenancemaintenance Double row angular contact Double row angular contact

bearing ( axial and radial bearing ( axial and radial loads)loads)

UprightUpright SpindleSpindle

Modeled using Modeled using SolidworksSolidworks®® Used to ensure fitUsed to ensure fit

Compatibility with other Compatibility with other componentscomponents

Clearances and interferenceClearances and interference

Front Hub/UprightFront Hub/Upright MaterialsMaterials

6061-T6 Aluminum6061-T6 Aluminum 304 Stainless Steel304 Stainless Steel

ManufacturingManufacturing CNC MillCNC Mill LatheLathe PressPress

Front Hub/UprightFront Hub/Upright VerificationVerification

WeightWeight Last years 32 lbs. This year Last years 32 lbs. This year

11.4 lbs. 11.4 lbs. 64% weight reduction64% weight reduction Under Ideal weight of 14 Under Ideal weight of 14

lbs.lbs. Track testingTrack testing

Handles loads under Handles loads under acceleration, deceleration, acceleration, deceleration, and corneringand cornering

Problems/ImprovementsProblems/Improvements Two Piece SeparationTwo Piece Separation SpacersSpacers Further Advanced Further Advanced

OptimizationOptimization Weight reductionWeight reduction Cost reductionCost reduction

DrivetrainDrivetrain Use of Common Use of Common

PartsParts Honda CBR 600 F1Honda CBR 600 F1 Limited Slip Limited Slip

DifferentialDifferential

Use of Common Use of Common MaterialsMaterials 4140 Steel4140 Steel 6061-T6 Aluminum6061-T6 Aluminum

Rear DifferentialRear Differential Aluminum HousingAluminum Housing

Zexel Torsen Limited Zexel Torsen Limited Slip DifferentialSlip Differential

Sealed BearingsSealed Bearings Retain Gear OilRetain Gear Oil

Check ValveCheck Valve Roll-Over and Tilt Roll-Over and Tilt

ProtectionProtection

Power TransmissionPower Transmission Axle ShaftsAxle Shafts

4140-3/4” Steel4140-3/4” Steel U-JointsU-Joints

Drive ShaftDrive Shaft Splined DriveSplined Drive Chain and SprocketChain and Sprocket

Rear Mono-BrakeRear Mono-Brake

Drive Train VerificationDrive Train Verification PerformancePerformance

Dyno-TestinigDyno-Testinig Road TestingRoad Testing

WeightWeight Target 50 lbsTarget 50 lbs

Manufacturing TimeManufacturing Time Target 15 hoursTarget 15 hours

Production CostProduction Cost Target $2000Target $2000

FailuresFailures Drive Axle WeldsDrive Axle Welds Shielded BearingsShielded Bearings

Changes?Changes?

Acceleration Torsion Acceleration Torsion TestingTesting

Aerodynamics & BodyAerodynamics & Body Modeled using 3-D software Modeled using 3-D software

package, SOLIDWORKS®package, SOLIDWORKS®

Forms CNC machined Forms CNC machined Allowed for precision forming Allowed for precision forming

and exact fitand exact fit

Material: 1/8” fiberglass mat w/ Material: 1/8” fiberglass mat w/

fine mat finishfine mat finish Light weight and durableLight weight and durable

Total Weight: 8.5 lbs. Total Weight: 8.5 lbs. Significantly below PDS targetSignificantly below PDS target

Body & Aerodynamics Body & Aerodynamics con’t…con’t…

Lift and Drag Coefficients (as effected by ground promimity)

00.05

0.10.15

0.20.25

0.30.35

0 0.05 0.1 0.15

h/L

Coe

ffic

ient

Drag CoefficientLift Coefficient

Estimated drag coefficient (CEstimated drag coefficient (CDD), front lift coefficient (C), front lift coefficient (CLL), drag force (D) and lift force (L)), drag force (D) and lift force (L) CCDD = 0.14 = 0.14 D = 1.950 lbfD = 1.950 lbf CCLL = 0.15 = 0.15 L = 0.910 lbfL = 0.910 lbf

© 1992 SAE

Body & Aerodynamics Body & Aerodynamics con’t…con’t…

Estimated skin drag coefficient (CEstimated skin drag coefficient (CFF) and surface shear force per unit ) and surface shear force per unit surface area (surface area (ττ) ) (friction resistance)(friction resistance)

CCFF = 4000 = 4000 ττ = 901.87 lbf/ft = 901.87 lbf/ft22

Source: Race Car Engineering, Katz

Body & Aerodynamics Body & Aerodynamics con’t…con’t…

Overall Performance EvaluationOverall Performance Evaluation Overall weight of car significantly minimizedOverall weight of car significantly minimized

PDS projected weight = 30 lbPDS projected weight = 30 lb Actual weight = 8.5 lb Actual weight = 8.5 lb

Dimensions of car w/in 2% of desiredDimensions of car w/in 2% of desired

Drag force minimized as specified in PDSDrag force minimized as specified in PDS Typical F-1 CTypical F-1 CD D = 1.07= 1.07 PSU Formula CPSU Formula CD D = 0.015= 0.015

Lift force acceptable but could be further minimized by introducing further Lift force acceptable but could be further minimized by introducing further down force components which were sacrificed to make room for critical down force components which were sacrificed to make room for critical components (i.e. intake apparatus, radiator)components (i.e. intake apparatus, radiator)

Typical F-1 CTypical F-1 CL L = -0.99= -0.99 PSU Formula CPSU Formula CL L = 0.015= 0.015

Cooling performance maximized by channeling air over water-cooled Cooling performance maximized by channeling air over water-cooled componentscomponents

average engine temperature w/o channeled air over radiator = 220average engine temperature w/o channeled air over radiator = 220°F°F average engine temperature w/ channeled air over radiator = 200°Faverage engine temperature w/ channeled air over radiator = 200°F

Performance in ActionPerformance in Action