2008 midwest spring proposal

7/28/2019 2008 Midwest Spring Proposal

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Mini Baja Midwest

An SAE College Team Competition

Prepared by: 2008 SAE Mini Baja Team

Florida Institute of Technology

150 W. University Blvd.

Melbourne, FL 32901


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Mini Baja Midwest.................................................................................................................1Background:...........................................................................................................................3Objectives:..............................................................................................................................4Team Roster and main responsibilities for this report:..........................................................5Team Organization:................................................................................................................5

Components / Subsystems:.....................................................................................................5Chassis and Body:..............................................................................................................6Power Train:.......................................................................................................................9

Top Speed:....................................................................................................................15Steering:...........................................................................................................................16Suspension:.......................................................................................................................17Brakes:..............................................................................................................................21

Budget:.................................................................................................................................22Timeline:..............................................................................................................................24Conclusion:...........................................................................................................................24Appendix A: References.....................................................................................................25

Appendix B: Competition Rules, Constraints, and Regulations.........................................26Competition Rules:...........................................................................................................26Constraints and Regulations:............................................................................................27

Appendix C: Scored Events................................................................................................29Scored Events:......................................................................................................................29

Static Events 300 POINTS............................................................................................29Design Report 100 POINTS......................................................................................29Design Evaluation 150 POINTS...............................................................................29Cost 50 POINTS........................................................................................................30Cost Report 10 POINTS............................................................................................30Prototype Cost 40 POINTS.......................................................................................30Acceleration 75 POINTS..........................................................................................31Traction (Chain Pulling) 75 POINTS.........................................................................31Maneuverability 75 POINTS....................................................................................32l.....................................................................................................................................32Mud Bog (Specialty) 75 POINTS.............................................................................33Durability 400 POINTS............................................................................................33

Appendix D: Design Timeline 33


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Background:

The SAE Mini Baja competition originated at the University of South Carolina in

1976, under the direction of Dr. John F. Stevens. Since that time, the Mini Baja Series hasgrown to become a premier engineering design series for university teams throughout the

country.

Mini Baja is comprised of three regional competitions that expose students to real life

engineering design processes: East, West, and Midwest. The students are to design and build

an off road vehicle that can withstand rugged outdoor terrain.

The object of the competition is to provide SAE student members with a challenging project

that involves the planning and manufacturing tasks found when introducing a new product to

the consumer industrial market. Teams compete against one another to have their design

accepted for manufacture by a fictitious firm. Students must function as a team to design,

build, test, promote, and race a vehicle within the limits of the rules, but also to generate

financial support for their project and manage their educational priorities.

Each team will compete using a 10 horsepower Briggs and Stratton engine that will be

donated by Briggs and Stratton Corporation. The engine is not to be altered in any way, which

will create a more competitive competition.

Florida Tech has entered the Mini Baja Midwest Competition five times, in which the

car must compete in dynamic tests such as acceleration, top-speed, hill climb, jumping, and

weight pulling. Our first year of competition, 1997, we ranked 38 th place out of 130 entries

overall, and won first place for structural integrity. Florida Tech entered again in 1998 and

ranked 26th overall with placements in the top five for top speed, hill climb, and acceleration.

In 2002, we registered but were only judged on our report because we were unable to bring the

car to competition. The car made it to competition in 2003, but was only allowed to participate

in the static categories because of minor safety problems. The current 2007 car is in the

building stage with a high potential of doing well at the Rochester Institute of TechnologyMidwest competition. This team is giving us a good foundation to learn from. Our goal for

2008 is to design and manufacture an efficient, award-winning machine.


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Objectives:

The objective of the Mini Baja is to apply our knowledge gained in class and put it into

practice. This project will give us an insight on the engineering design process and will allow

us to refine our technical skills learned in classes. Communication between team members as

well as between different design teams within the group is essential for a successful project.

Team members must also know how to balance schoolwork, the Mini Baja, and personal

responsibilities.

The primary goal for this competition is to abide by all the regulations set forth by SAE.

This is a necessary step as it will ensure the safety of the driver and will prevent our vehicle

from being disqualified. A goal for the team is to design and produce an easy to drive manual

transmission vehicle with a fully independent suspension. Frame design and fender panels will

also be designed to give the vehicle an aggressive appearance. Construction costs will be keptlow in order to stay competitive in the marketplace and testing of our vehicle before

competition is a must.


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Team Roster and main responsibilities for this report:

Kenneth Mandeville (Team Leader) Frame/Chassis, suspension and editing

Paul Bunkers - SteeringJeremy Shenker Drive train (shifting mechanism)

Chad Phelps Suspension, chassis and editing

Jesse Soto Drive train and Brakes

Craig Wilkinson Drive train (top speed and Acceleration)

Team Organization:

Components / Subsystems:

Chassis and Body

Power Train

Suspension

Steering and Braking

M a n u f a c t u r i n g :

E v e r y o n e

C h a s s i s :

K e n M a n d e v i l l e

C h a d P h e l p sC r a i g W i l k i n s o n

S t e e r i n g a n d B r a k i n g

J e r e m y S c h e n k e r

J e s s e S o t oP a u l B u n k e r s

S u s p e n s i o n


C h a d P h e l p sC r a i g W i l k i n s o n

D r i v e t r a i n g

J e r e m y S c h e n k e r

J e s s e S o t oP a u l B u n k e r s

D e s i g n T e a m s F u n d i n g :

E v e r y o n e

T e a m L e a d e r :



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Chassis and Body:

The chassis is the backbone of the Mini-Baja, it must support all the cars

subassemblies as well as protect the driver. The chassis design is crucial to the success of the

project because if the chassis fails, that puts the baja and the driver at tremendous risk. The

rules give a lot of restraints on chassis design for obvious safety reasons, so the key will be to

choosing the right material. There are three basic factors that will determine the material we

use for the chassis: strength, weight, and cost. Thus, we need to pick a material with a high

strength-to-weight ratio. Below are the material rules:

31.5 Roll Cage & Bracing MaterialsThe material used for the required roll cage components specified in 31.2.1 must, at minimum, be:

(A) Circular steel tubing with an outside diameter of 2.5 cm (1 inch) and a wall thickness of 3.05 mm (.120

inch) and a carbon content of at least .18.

OR

(B) Steel members with at least equal bending stiffness and bending strength to 1018 steel having a circular

cross section with a 2.5 cm (1 inch) OD and a wall thickness of 3.05 mm (.120 inch).

NOTE: The use of alloy steel does not allow the wall thickness to be thinner than 1.57 mm (.062 inch).

The bending stiffness and bending strength have to be calculated about an axis that gives the lowest value.

Bending stiffness is proportional by the EI product and bending strength is given by the value of SyI/c, (for

1018 steel the values are; Sy = 370 Mpa (53.7 ksi) E = 205 GPa (29,700 ksi)).

Many previous teams have used 1.25 OD with 0.095 wall thickness chromoly steel.

This size gives superior bending strength while keeping the weight lower than the 1inch OD

with 0.125 wall thickness. We are going to conduct our own research to choosing the best

material. Our choice of material is limited to steel by the rules, so we will focus our research

on the best steel and dimension to use.

This years 2007 Mini-Baja team found that most ATV builders use 4130 chromoly.

With their research they found that it has the greatest ultimate and yield tensile strength, the

highest modulus of elasticity, while still having low density compared to other steel. We will

use last years research as a starting point for our own in coming up with the best material

choice to meet our three design criteria: strength, weight and cost.

A factor last years team looked into was whether to use square or round tubes. The

rules specify to use round 1018 steel tubing for the chassis. Round tubing is lighter than


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square because smaller gauge sizes can be used to handle the same stress as a wider square

tube. Round tubing is harder to manufacture but out performs the square tubing. It is still

early to decide the type of material we are going to use for the chassis but we are using a form

of chromoly steel in round tubing. Table 1 seen below displays some basic values comparing

4130-chromoly steel and 1018-steel.

4130 Chromoly 1018 Steel

Yield strength 108440 kpsi 55100 kpsi

Modulus of Elasticity 29700 kpsi 29000 kpsi

Bulk Modulus 20300 kpsi 20300 kpsi

Density 0.284 lb/in 0.284 lb/in

Elongation to break 25.1% 16 %

[Table 1: 4130 Chromoly vs. 1018 Steel. [Reference 6]]

The purpose of the Mini Baja frame is to provide a rigid base for the rest of the

components to attach to. In order to function properly the suspension needs a firm structure,

the drive train must also be held stiffly so that proper clearances are maintained. The roll cage

also will need a firm structure to aid it in protecting the driver in the event of a rollover or

collision. To ensure that our frame can fulfill these specifications we must estimate the forces

that it will be subjected to under these conditions. The suspension forces are explained in our

suspension section, and a slow rollover will not be much more than our car weight. The frame

must be designed to withstand these forces.

To estimate an impact force we used the below equation:

dfW

mvmvW

net

initialfinalnet

=

=22

2

1

2

1

This equation states that the change in kinetic energy is equal to the net work done, and the

work needed to stop the car is equal to the force times the distance. So using the estimated

values below we estimate an impact force of approximately 10,000 pounds. [Reference 4]


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poundsf

mphv

m

inchesd

mvdf

initail

initial

10364

5.13

pounds425sluggs13.22

3

2

1 2

=

=

==

=

=

The frame does not need to survive this crash so long as it protects the driver in this

situation. However the mounting for the safety harness does have to survive this crash. The

drivers change in acceleration during this crash will create the most stress on these mounts.

Thin walled tubing, which we hope to use, performs very well in compression and

tension, but not as well in bending. Our shock mounts will undergo almost all of the

suspension forces. These forces are shown below in figure 1. In this figure the loads due to

the suspension are in green and the reaction forces in red. The shock mount should be

triangulated to distribute the force among other beams instead of just one. The same goes for

our engine/drive train mounts. Those mounts need to be stiff enough to withstand the vibration

and torque an engine will output.

[Figure 1: Loads and reaction forces on suspension. (C. Phelps)]


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Power Train:

A power train is an assembly of gears and associated parts by which power from the

engine is transmitted to a driving axle, the tires, and finally the ground. Briggs and Stratton

provides us with an engine that has a maximum output of 10-hp, and a rev limiter at 3800rpm.

As per the rules of the competition, the engine cannot be modified in any way. This restriction

causes the design emphasis to be placed on the choice of transmission. For the transmission we

have several options;

A manual transmission (4 or 5 speed): this system would allow the driver to select the

right gear from the available gears allowing more control over the vehicle. This is seen on most

manual cars with a standard H pattern.

A sequential transmission: this is similar to the manual transmission, but the H

pattern is eliminated and replaced with a different shifting pattern. For example in a race car,

the motion of the shift lever is either push forward to up-shift or pull backward to

downshift. These transmissions are usually found in either motorcycles or all terrain vehicles.

A Continuously Variable Transmission (CVT) Automatic transmission: A CVT consists of 2

variable pulleys and a belt. The most common type of CVT operates on a pulley system that

allows an infinite variability between highest and lowest gears with no discrete steps or shifts.

As mentioned above, the CVT has three basic components:

1. A high-power metal or rubber belt

2. A variable-input "driving" pulley

3. An output "driven" pulley

The pulleys are torque sensitive; when more torque is needed such as during a steep

hill climb situation, the transmission automatically downshifts to provide more torque. When

moving on a long flat terrain not much torque is required, so the transmission shifts to a higher

gear, giving the wheels more speed as necessary.


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The power and torque curve of the Briggs & Stratton 10 hp OHV Intek Model 205432

Type 0036-e1 engine that we plan to use is displayed on the next page in Figure 2. In past

years the mini baja has used a CVT transmission, which keeps the engine at peak power. The

CVT works well with a lightweight low torque vehicle under a light load. When the load is

significant or when the belts are wet they tend to slip resulting in power loss. With two of our

dynamic events putting a heavy load on the engine and transmission and one of those events

possibly getting our belts wet a CVT doesnt seem to be the best choice. The team is also

interested in conducting research to see if the advantages of the CVT discussed above are

offset by the inherent drive train inefficiency of the belt and pulley system necessary in a CVT.

Since the engine only produces 10-hp at the rpm it is limited to, minimizing drive train loss is

important.

Gearbox

Figure 2: Mini-Baja with motorcycle Gearbox [Picture taken by Marcus Maldonado]

This is where we would like to put our gearbox,directly beneath the engine, with the enginemounted on top of it.


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[Figure 3: Plot of horsepower and torque of the engine used in the competition. Reference 1.]

CVT

Advantages vs. Disadvantages

Eliminates Shift locks Smoother ride Belt slips under heavy and wet conditions

Keeps the vehicle in optimum power range Durability in belts

Less driver error Boring to drive

More friction

More rotating mass

[Table 2: Advantages and Disadvantages of a CVT.]

As stated from the rules of the competition:

10.2 Competition Goals

Each teams goal is to design and build a prototype of a rugged, single seat, off-road

recreational vehicle intended for sale to the non-professional weekend off-road

enthusiast. The vehicle must be safe, easily transported, easily maintained and fun to

drive. It should be able to negotiate rough terrain in all types of weather without

damage.

We feel that an off-road enthusiast would consider a manual transmission more fun todrive over a CVT. Therefore we plan to use a sequential manual transmission because it has

better acceleration from a standing start. This will give the off- road enthusiast more of a thrill

of driving. This transmission will also not suffer from poor acceleration if the transmission is

wet, as a CVT would. This will also allow the driver to select the right gear for the different

obstacles. For example a driver can keep the transmission in a low gear if a low speed

maneuver is necessary. We also hope that using a well designed transmission will give us

more points in the competition for originality because almost all of the teams are using a CVT

system due to its simplicity to design around.

The decision to go with a manual transmission leads to further design complications.

This is because the clutch pedal will need to be installed in an area, which is already tight with

just gas and brake pedals. It also adds an additional requirement of the driver during the

already hectic competition. That would require special driving techniques such as heel-toe

shifting where the driver uses one foot to step on the brake to slow the car while at the same


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time stepping on the gas to rev match the engine with the cars speed. The other foot would then

be operating the clutch. Being a vehicle for off road enthusiasts we expect that potential

customers may not possess the skills required for operating three pedals at once. That is why

we came up with a design for the shifter that will operate the clutch automatically when the

driver up shifts and downshifts. This design is made possible because we are using a sequential

manual gearbox (SMG) from a motorcycle, which only has back and forth movement to shift

instead of the standard H pattern on automotive manual transmissions.

How does it work? The shift arm follows a linear cam so that as it moves fore and aft

from center, it also moves inward (towards the driver). This inward movement will operate the

clutch, disengaging the transmission from the engine, allowing for a shift to take place. When

the driver releases the shifter, a spring holds it against the cam so that the clutch re-engages the

engine and transmission. To start moving from a stop, the driver will shift into first and ease

the shifter forward (the shift pattern on SMGs is 1st is down, N, 2nd, 3rd, 4th are up) to slowly

engage the clutch, while stepping on the gas. The design also allows the driver to feather the

clutch if they have the need, by simply pushing the shifter towards them. The clutch linkage

will be a cable, as it will need movement, the shift linkage will be a rod linkage as it will only

move fore and aft.

[Figure 4: Shifter Mechanism (J. Schenker)]


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Acceleration:

The acceleration event tests how fast the vehicle can accelerate either 100 or 150 feet. Whenthe signal is given, the driver will attempt to travel the 100 or 150 feet faster than the other

teams. If the acceleration time is more than twice that of the fastest car, then the score will not

be counted. The points for this event are scored as follows:

Acceleration score = 60 or 75 x [(T longest T yours)/(T longest T shortest)]

T shortest is the fastest time by any team

T longest is either (a.) the slowest time by any team, or (b.) 2.5 times the fastest time

whichever is the shorter interval

T yours is your teams best time

In 2006, the winning acceleration time was 5.91 seconds, which was roughly one whole second

faster than most of the other vehicles. Out teams goal will be to achieve 7.0 seconds in this

event, which will put us in the top 30 percent in the acceleration event. Since our vehicle will

be using a manual transmission instead of a CVT, our acceleration time will be negatively

effected because of shift delay from the driver. The manual transmission is also at a

disadvantage due to the more complicated launching of a manual transmission compared to a

CVT. The manual transmission will benefit our vehicle more in the traction, hill climb and

chain pulling. We can enhance acceleration by reducing the weight of our vehicle.

Top Speed:

The vehicle will achieve a top speed of roughly 40 miles per hour. By achieving an aboveaverage top speed, we will benefit most in the endurance race. Where the vehicle lacks in

acceleration, it will make up in top speed.


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Steering:

The steering system is a vital and crucial component in any vehicle. It was decided

early that the steering system needed to be the best but also small. With these restrictions in

mind we have decided on a rack and pinion style steering system. The rack and pinion style

has many has many benefits. First, the rack and pinion isnt sloppy at the center point and

gives the drive a large range of motion. Second, the rack and pinion provides a large degree of

feedback and allows the driver to feel the ground. Third, the rack and pinion places the pivot

points of the steering system near the pivot points of the suspension system which greatly

reducing bump steer. Finally, the rack and pinion unit is very compact and fits more easily into

the front frame.

Looking at online pictures and past years designs we have notice a lack of space in the

cockpit down by the drivers feet. This lack of space causes this area to be widened to allow

the pedals, drivers feet and steering column which in turn makes the A arm shorter to keep

within the width restrictions. We decided to put a bend in the steering column and putting the

rack and pinion steering behind the pedals. Moving the rack and pinion steering behind the

pedals (figure 5) will mean that the tie rods will connect to the front of the steering knuckle

unlike past years. Doing this will hopefully allow us to cut the area needed for the pedals and

steering column in half. This will happen because the driver will not need to rap their feet and

legs around the steering column. Moving the tie rods will cause a problem because the tie rods

are no longer protected by the cars body and suspension. We plan to fix this by making the

lower arm wide and beefy. We also hope to tuck the tie rod as close to the center point on the

steering knuckle.

The calculations below were made assuming use of a 12mm rod. This is the rod that

teams have used in the past. The equations below come from reference 5.

Steering Analysis:

Tube Rod moment of inertia:

( ) 44444 0076.))634(.)75((.6464

ininindDI ===

Tube Rod cross-sectional area:


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( )( ) 22222 126.)634(.75(.4

)(4

ininindDA ===

Solid Rod moment:

444

0024.64

)472(.

64in

inDI ===

Solid Rod cross-sectional area:2

22

175.64

)472(.

4in

inDA ===

Max bending moment allowed by rods:

inlbin

inpsi

c

IM === 642

236.

)0024)(.63100( 4

Figure 5: A picture of the rack and pinion steering which is place such that the tie rods aremounted on the front of the steering knuckle. This also shows that the A arms can protectthe tie rods if they are mounted in this configuration.(http://www.powersportsmax.com)

Suspension:

A good suspension is vital to the performance of an off-road vehicle. The suspension

must keep the tires on the ground at all times to ensure optimal traction and grip as the vehicle

transverses rough terrain. An additional purpose of the suspension is to isolate the shocks

associated with traveling over rough terrain from the body of the vehicle, thus sparing the

driver. This is particularly important for our design, as the driver must be able to drive the car

for extended periods of time during the endurance race. A four-wheel independent suspension


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is the optimal arrangement, allowing each wheel to move independently from the others, as the

wheels experience varying obstacles, something that occurs quite often in an off-road

environment. Therefore it is common to see independent suspension systems for maximum

performance oriented vehicles.

We intend to use a multi-link suspension system, as this system is advantageous in

allowing the vehicle to flex more as it adjusts to keep the wheels planted. An example of a

four-link suspension setup that is similar to what we intend to design for our vehicle can be

seen in the picture below.

[Figure 6: Four-link off-road independent rear suspension. Reference #2.]

Another key element to our suspension will be the shock absorbers. The shocks we

intend to use are Fox AirShox, as air shocks provide numerous benefits. The most obvious

of which is weight savings, as they require no heavy steel springs. Additionally, as

demonstrated in the graph below in Figure 5, air shocks are able to provide progressive force

rather than the linear force of a standard coil spring. This helps prevent the shock/suspension

from bottoming out, which can be hard on the suspension components, as well as the

occupant of the vehicle. Using air as the spring also makes tuning the suspension to different

driving conditions easier, as the pressure in the shocks can be adjusted, changing their force


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and compression characteristics. This will also enable us to take into account the weight of

different drivers as we fine-tune the handling of the vehicle.

[Figure 7: Force vs. Travel comparing a Fox AirShox to a standard coil-over spring. Reference # 3.]

The shock loads that the suspension will have to deal with have been estimated in

the following table. The mini baja was estimated to weigh 625-lbs. The force of gravity

used in this estimation was 32.2-(ft/s^2), and the travel of the shocks was used as the

deflection of the suspension, which is 1-ft (12-inches).


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Height of drop(ft) Impact Force (lbf) Kenetic Energy (lb*ft) Time (s) Impact Velocity (ft/s)

10 6230.650155 6230.650155 0.786889 25.33784111

9 5607.585139 5607.585139 0.746509 24.03758667

8 4984.520124 4984.520124 0.703815 22.66285405

7 4361.455108 4361.455108 0.658359 21.199158816 3738.390093 3738.390093 0.609522 19.62660733

5 3115.325077 3115.325077 0.556415 17.91655927

4 2492.260062 2492.260062 0.497673 16.02505778

3 1869.195046 1869.195046 0.430997 13.87810713

2 1869.195046 1869.195046 0.351908 11.33142702

1 1869.195046 1869.195046 0.248836 8.012528889

[Table 3: Impact force generated by the vehicle falling from a

variety of heights]

Where Hd is the height of the drop,v i is the Impact Velocity,KE is the Kinetic Energy which must be absorbed,Fi is the Impact Force,m is the mass of the vehicle, andS is the displacement of the shock (travel)

[Equations reference # 4.]

The lateral loads that the suspension would be subjected to were also estimated. For

the lateral forces, a coefficient of friction for asphalt was used, as this will exert more

forces on the wheels than when the vehicle is on a more slippery surface such as dirt or

mud. The coefficient of friction used was 1.2. The wheel may have the entire weight of

the vehicle exerted on it in some extreme cases, so as a conservative estimate; 625-lbs was

chosen as the maximum normal force applied to a single wheel.

The friction equation was used.lbfF

F

FF n

750

)625(*)2.1(

=

=

=


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Thus the maximum lateral load applied to the suspension is 750lbf, while the

maximum shock load applied to the suspension from the vehicle undergoing a 10ft drops is

6231-lbs. The shock load per wheel is therefore 1560lbf for a 10 ft drop. We do not expect

such large drops in the competition we will be attending however.

Brakes:

SAE has outlined various requirements for the braking system of the competition mini

Baja. The braking system must be a hydraulic system with all braking controlled from a

single-foot mechanism. The braking system must be able to lock all four wheels in static and

dynamic conditions, on paved and unpaved surfaces. SAE requires that the system contain two

independent hydraulic systems, each with their own fluid reserves (Figure 10). A brake light

with lens meeting or exceeding SAE standards is also mandated and must be independent ofthe kill switch. With all required components the braking system must be able to completely

stop the vehicle from thirty miles per hour in 49.2 feet.

Figure 8: Diagram of Braking Forces [Ref SAE Road Show II]


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Figure 9: Diagram for a Single Disk Brake [Ref SAE Road Show II]

Above is the equation used to find the stopping force for each disk brake on theMini-Baja. This force will have to equal the F1 (Figure 8) force so all the wheels willlock to pass the braking requirements of SAE.

Figure 10: Four Disk Brake setup that will be used on our vehicle [SAE Road show II]

Budget:

The following budget report is an estimation based on the current mini baja team. It is

divided amongst the following five categories: Power train, the steering and brakes, the

chassis and body, the ergonomics and suspension, and miscellaneous. Each subsystem is

further broken down to the parts that it consists of along with its estimated price. Please note

this is only a preliminary financial plan, the exact costs have not yet been investigated.

Fundraising will be an ongoing task and we plan to have most of our expenses paid for by the

sponsors that we acquire.

)(2 fRpAm

Aw

R

rF


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Power Train

Engine $150*

Electrical System $100

Transmission $600

Steering and Brakes

Steering Assembly $500

Master Cylinders $200

Brake Discs $200

Pedal Assembly $150

Brake Lines/Fittings $150

Wheels/Tires $750

Bearings $450

Axle/Hubs $350

Chassis and Body

Chromoly $800

Rod Ends $150

Bolts and Washers $100

Ergonomics and Suspension

Seat $150

Shocks $800Miscellaneous

Tools $500

Maintenance Supplies $200

Metal Stock $200

Team Uniforms $150

Spare Parts $1000

Travel Expenses $1200

Total $8850

* Shipping


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Timeline:

Figure 6: Timeline (A more detailed design timeline can be found in appendix D)

Conclusion:

Our main goal for this project is to fund, design and build an off-road Mini Baja

vehicle with a unique transmission. Once built, we will take it to the SAE Mini Baja Midwest

competition. Our job for the competition is to convince a hypothetical company that our design

is superior and it could be beneficial if introduced to the market. In addition, we hope to have

fun and keep the project interesting. This project will provide real world experience that we

will be able to take with us as we move in to industry work. We will increase our level of

communication skills as well as our teamwork skills.

Competition

TestDrive/Redesign

Manufacturing

Research/Design

Fundraising

JuneMayAprilMarchFebruaryJanuaryDecemberNovemberOctoberSeptemberAugustJuly

Spring Semester 2008Fall Semester 2007


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Appendix A: ReferencesPrimary References:

1. Briggs and Stratton website.

2. The Buggy Shop

3. Fox Racing Fox AirShox manual.

4. Hibbler, Russel C. Engineering Mechanics: Dynamics, 10th edition. Prentice

Hall; 10 edition (November 11, 2003)

5. Ferdinand P. Beer, Mechanics of Materials, Fourth Edition. MC Graw Hill; fourth

edition (2006)

6. Material Library

Other References:

Mark, Wan. "Different Types of Chassis." Autozine. 2000. Autozine Technical School. 21

Mar. 2006 .

Xlr8 Gs-R. "Diy Front Strut Bar." Road Racing/Autocross. 20 Sept. 2002. 21 Mar. 2006

.

"Chromoly Tube." Lethal Concepts. 21 Mar. 2006

.

"Frame Design." Factory Five Racing. 27 Mar. 2006

.

http://www.sae.org/students/mbrules.pdf

http://www.baja.wisc.edu/

http://www.hoffcocomet.com/comet/aftermarket-torque-converters.asp#700


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since its previous competition and (2) the modified vehicle meets all of the current

years rules.

9) Teams must register for each Mini Baja competition they intend to enter by the

deadline given in the Action Deadlines listed in the Appendix.

10) The vehicle design should be attractive to consumers because of its visual appearance,

performance, reliability and ease of operation and maintenance.

11) The vehicle must have four (4) or more wheels not in a straight line.

12) The vehicle must be capable of safe operation over rough land terrain including

obstructions such as rocks, sand, jumps, logs, steep inclines, mud and shallow water in

any or all combinations and in any type of weather including rain, snow and ice.

13) Required engine: Briggs & Stratton 10 hp OHV Intek Model 205432 Type 0036-e1

Constraints and Regulations:The constraints and regulations governing the Mini Baja Midwest project were prepared to

enable an acceptable level of vehicle safety while maintaining fair competition environment

among teams. A more detailed list of the constraints and regulations governing the Mini Baja

competition can be found on the SAEs website under Student Competitions Mini Baja

Midwest. Below is a compiled list of the most important constraints and regulations.

1. Roll cages are regulated to insure the safety and sound structure of the vehicle in the

event of a crash. Configurations, materials, bolt connections, welds, and clearances

must be followed.

2. Requirements such as firewall, engine location, exhaust, shielding, kill switches,

throttle and fire extinguishers must be met.

3. Configurations for the drivers restraints must be followed.


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4. Other subassemblies such as the breaking system, fuel system, steering, and

suspension, have specified limitations as well that can be found on the web site

mentioned above.

5. The only fuel permitted is a grade of automotive gasoline consisting of hydrocarbon

compounds. The gasoline may contain anti-oxidants, metal deactivators, corrosion

inhibitors, or lead alkyl compounds such as tetra-ethyl lead. The addition of nitrogen

bearing additives, or additives designed to liberate oxygen is strictly prohibited.

6. Workmanship regulations on items such as fasteners, lock wire, and welds must be

adhered to.

7. Safety from power train guards and other similar mechanisms must be used.

8. The driver must have proper personal protection such as helmet, goggles, support

collar, and the required type of clothing.

9. All governors must remain stock and must not be tampered with or altered in any way.

10. Other rules and procedures that must be followed are attendance of driver meetings,

pre-inspections, pit rules, refueling, general team behavior, and safety.

Any protests for violations must be addressed to the National Technical Inspectors of the

Mini Baja competition.


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Appendix C: Scored Events

Scored Events:

The scored events for the Mini Baja Midwest competition are grouped into two categories

(1) Static Events worth a maximum of 300 points and (2) Dynamic events which are worth 700

points.

Static Events 300 POINTS

Design Report 100 POINTS

The design report is a technical paper detailing all stages of the design process it is a

maximum of ten (10) pages long excluding the cover page. An optional four (4) pages of

charts, graphics and photographs may be included in the report but must contain no other text

but captions.

Design Evaluation 150 POINTS

Designs will be evaluated at the event site on the first full day of the competition. Cars are

expected to be presented in a finished condition and any incomplete section may receive a

reduced score or zero points for any area that the judges are unable to evaluate. Judges also

have the right to refuse to evaluate incomplete reports. Team members are expected to be able

to answer any questions on the rationale behind their design decisions. The areas scored are as

follows:

1) Originality and innovation 35 points

2) Suspension and brake system 25 points

3) Power train 15 points

4) Structural design 15 points

5) Craftsmanship 15 points

6) Operator Comfort 15 points


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7) Feasibility for mass production 15 points

8) Serviceability 15 points

Cost 50 POINTS

The cost events are scored separately by judges but should be treated as one event with two

parts.

Cost Report 10 POINTS

This event covers costs for the vehicle. It should include receipts, price tags, invoices, on-

line prices, and other documentation. It is a means to verify the actual cost of the vehicle and is

divided into subsystems. The cost report is an accurate and honest report of the cost of all

materials, labor and fabrication. The time taken to assemble these parts is also reported. Judges

will correct all times and costs that they believe to be lower than expected and cannot be

justified in the report.

Prototype Cost 40 POINTS

During this event the team is presented with the judges correction of the cost of producing

their vehicle. The prototype cost score is given depending on a teams corrected vehicle cost

when compared to the least expensive corrected cost and the most expensive corrected cost for

a vehicle in the competition.

Prototype cost = 40 x [(Max Cost Your Cost)/(Max Cost Lowest Cost)]


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Dynamic Events 700 POINTS:

Acceleration 75 POINTS

This event determines the acceleration capability of the vehicle. Each team gets two

attempts along either a 100 or 150-foot flat course and the better of the two runs will be scored.

A false or stalled start will be required to be run again and if repeated will result in

disqualification, include running off the course will also result in disqualification. Top speed is

determined at the end of the acceleration run. It is captured by a speed trap or other acceptable

methods. Teams with a time that is more than twice the time of the fastest team will not be

scored.Acceleration score = 75 x [(Tlongest Tyours)/(Tlongest Tshortest)]

Traction (Chain Pulling) 75 POINTS

The event organized for the 2006 Mid West competition is a pulling event. The vehicle

will straddle a chain attached to a sled and attempt to pull it. Each team gets two attempts.

When forward motion has stopped, the distance that the vehicle covered is measured and the

furthest distance wins. However, there may be a set distance determined that all vehicles must

pull and the run is timed.


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Maneuverability 75 POINTS

This event tests the vehicles suspension handling and steering. The vehicle must

maneuver around logs, rocks, tight turns, over ground clearance obstacles, jumps and along

inclines among other obstacles. To receive a score a vehicle must complete the course by not

exceeding two and a half times that of the fastest vehicle. Two runs are allowed and the best

time after penalties are assessed will be used for scoring. Penalties include moving a pylon,

deliberate course violations, and false starts.

The Honda Hot Lap Maneuverability (Tentative)

l


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Mud Bog (Specialty) 75 POINTS

This event demonstrates the vehicles low speed power, suspension, and traction. Each

vehicle makes two attempts to travel down a 20-degree incline into and across a 24 meter long

pit of mud and up a 20 degree incline at the other end. Each vehicle is timed and a full run is

when the front tires of the car passes the top of the far incline. If vehicle goes off course or

rolls over it will disqualified. If the vehicle is unable to complete the course the distance that it

has covered will be scored. Otherwise the time taken to cross the obstacle will be used.

Durability 400 POINTS

The vehicles will participate in an endurance course where a single lap is approximately

1.4 miles. During the endurance event if a vehicle is pulled through an obstacle, they will be

towed back to the pits which will bypass the lap counter. This will be a progressive course

where approximately 10 obstacles will be used at the beginning of the event and then one

obstacle (increasing in difficulty) will be added every 15 minutes until all obstacles are open.

One or two more obstacles are anticipated.


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2008 midwest spring proposal

Documents