RX7Aggie

from austin? t.u.?

RX7Aggie

i see yall also have a body where you have to remove the suspension to take off the body? it might look good, but it 's the biggest PITA!



oh well, we only have to put it on and take it off for roll-out and the competition, we wont test and tune with it on.



i'll get pics of the paint job.



here's how it's supposed to look (my idea):

inanimate_object

What exactly am I looking at here - looks very interesting .



Mark

Cheers!

Can you give more details? Yes i agree the shocks are stiff when the spring is installed with preload. I have actually never taken off the spring to get the shock by itself and seeing how stiff it is.



What spring rates are u using?

I'm not sure about the prodampening, the shocks we run are from the 2002 model year.



We are using roughly between 0.6 to 0.9 installation ratio for the rear, the front is roughly 0.8??? i think, i can't remember. We too use almost the full range of the shock travel.



What type of suspension are you using? pull or push rod system?





What is wrong with CNC? it's great, you program it and you go home... we have 3 brand new HAAS CNC machines, one of which have auto tool change. the other two are not, and there are 2 older older CNC machines.



we also ahve three CNC lathes



Solidedge can save an IGS file, and then you load the IGS file into mastercam mill/lathe9 and u define the tool path, could'nt be easier. We'll easy for several on the team.



The precision and speed of CNC is amazing.



Our body is made from Al skin-Balsa core sheet, used normally to line hte floors of cargo planes. Strength and stiffness is amazing, unless it gets wet... water + balsa core = rot = crash.



Our car is made into a monocoque for the front with an chromoloy/mono hybrid this year. The only thing fibreglass on the car is the front nose cone, i think it's 3 layers of fibreglass, took 2 people 3 weeks to shape it they would say they made it. the fibreglass is purchased from UScomposites, it is 6 oz e glass cloth.



The nose cone can be taken on and off in 5 seconds, no suspension peicies need to be removed, think of cart/irl/f1 style nose cone, except our does not carry any loads.



We use a diff off a honda ATV, it is more then 1/2 the weight of a zexel torsen unit. I'm not sure on teh specs.



Our halfshafts are also from some ATV. We modify them on the CNC lathe.



The wheels are bogart racing, super light, it think each wheel weighed in at less then 7 lbs each? i can't remember.

Cheers!

oh ya... um. we used solidege v14. I didn't draw the car, the manager is a solidedge expert and he put the car asssembly together.

Apex13B

i still think the rear roll center looks fucked up, maybe if i was there in person it would look different.



I've got our shop's car apart still, its almost done (stupid reynard xtrac gearbox)

Cheers!

For which car? the roll centre is directly on the groud for the 2004 Queen's Car.



I didn't even really use roll centres to design the rear suspension. Why would u when there are software that can account for the change in the roll centre heights as the suspension moves?

Cheers!

http://www.sae.org/students/formulaseries.htm



2003 Formula SAE® Rules 7

1. CONCEPT OF THE COMPETITION

1.1 COMPETITION OBJECTIVE

The Formula SAE® competition is for SAE student members to conceive, design,

fabricate, and compete with small formula-style racing cars. The restrictions on the

car frame and engine are limited so that the knowledge, creativity, and imagination

of the students are challenged. The cars are built with a team effort over a period of

about one year and are taken to the annual competition for judging and comparison

with approximately 120 other vehicles from colleges and universities throughout the

world. The end result is a great experience for young engineers in a meaningful

engineering project as well as the opportunity of working in a dedicated team effort.

1.2 VEHICLE DESIGN OBJECTIVES

For the purpose of this competition, the students are to assume that a manufacturing

firm has engaged them to produce a prototype car for evaluation as a production

item. The intended sales market is the nonprofessional weekend autocross racer.

Therefore, the car must have very high performance in terms of its acceleration,

braking, and handling qualities. The car must be low in cost, easy to maintain, and

reliable. In addition, the car’s marketability is enhanced by other factors such as

aesthetics, comfort and use of common parts. The manufacturing firm is planning to

produce four (4) cars per day for a limited production run and the prototype vehicle

should actually cost below $25,000. The challenge to the design team is to design

and fabricate a prototype car that best meets these goals and intents. Each design will

be compared and judged with other competing designs to determine the best overall

car.

1.3 JUDGING CATEGORIES

The cars are judged in a series of static and dynamic events including: technical

inspection, cost, presentation, and engineering design, solo performance trials, and

high performance track endurance. These events are scored to determine how well

the car performs. In each event, the manufacturing firm has specified minimum

acceptable performance levels that are reflected in the scoring equations. The

following points are possible:

2003 Formula SAE® Rules 8

Static Events

Presentation 75

Engineering Design 150

Cost Analysis 100

Dynamic Events

Acceleration 75

Skid-Pad 50

Autocross 150

Fuel Economy 50

Endurance 350

Total Points 1,000

1.4 THE 2004 FORMULA SAE SERIES

The 2004 Formula SAE Series consists of three (3) competitions:

1. Formula SAE held in the United States

2. Formula Student held in the United Kingdom

3. Formula SAE Australasia held in Australia.

All Formula SAE competitions have open registration policies and accept student

teams representing universities from any country.

Formula Student and Formula SAE Australasia may have some minor rule variations

specific to those competitions. Such variations are published on the individual

competition websites.

1.5 THE FORMULA SAE COMPETITION YEAR

For the purpose of defining first, second and third year cars a competition “year” is

any consecutive run of the Series, i.e. Formula SAE, Formula Student and Formula

SAE – Australasia, held within a roughly 12 month period counting from the event

in which a vehicle first competes. For example, a car that competes first in Formula

SAE Australasia is classified as a “first year car” until the following year’s Formula

SAE Australasia competition.

Note: Teams are reminded that their vehicles must comply with the rules in effect

for each competition they enter.

2. ELIGIBILITY

2.1 INDIVIDUAL PARTICIPANT REQUIREMENTS

Eligibility is limited to undergraduate and graduate students to insure that this is an

engineering competition rather than a race. Individual members of teams

participating in this competition must satisfy the following requirements:

Student Status: Team members must be enrolled as degree seeking undergraduate or

graduate students in a college or university. Team members who have graduated

during the seven (7) month period prior to the competition remain eligible to

participate. Team members must be paid SAE members to compete.

Apex13B

because i'm old school cheers, to me CAD means cardboard aided design.



i cant invest tens of thousands of dollars in solidworks, PROe and autoCAD to mathamatically compensate a roll center on a car, or goemetric changes as the suspensions compresses and rebounds

Cheers!

true, i haven't redesigned my Fc suspension system yet.

=)



U technically don't need all that fancy crap, simple geometry and using numerical approximations can determine the amount of camber gain during wheel centre displacements.



I miss the good old days.