Brake Caliper Design

[Bryan]

For the teams that have designed and manufactured your own multi-piston brake calipers in the past, how did you transfer the fluid between pistons on each side of the caliper? I understand how to transfer it from one side of the caliper to the other, but not between the different pistons. Also what kinda of material did you use to make them out of and do you think it is a worth doing? Thanks

[Bryan]

For the teams that have designed and manufactured your own multi-piston brake calipers in the past, how did you transfer the fluid between pistons on each side of the caliper? I understand how to transfer it from one side of the caliper to the other, but not between the different pistons. Also what kinda of material did you use to make them out of and do you think it is a worth doing? Thanks

[clausen]

Further to the above question, what you the people that make their own callipers get out of their own designs that isn't available in the many motorbike callipers that are readily and cheaply available?

Regards

Paul Clausen
Uni of Adelaide

[Rumple]

To transfer the fluid from one piston bore to another you drill a hole at the bottom of the piston bores connecting them. Calipers and pistons were made from 7075.

Reasons for custom calipers:
1. Packaging
2. Increased brake effective radius
3. Huge selling point for design judges
4. Same price in cost report
5. Great learning experience
6. Best in Class Braking System Award
7. Pride in being one of few teams with their own custom calipers
8. They are lighter
9. They look sweet!

Steve Rumple
U of Michigan- AA

[John Gregor]

This is a design competition. It is not about just buying a whole bunch of parts off the shelf and bolting them together.

[RichE]

In the design debrief for the formula student event Neil Anderson was quite critical of teams that had designed their own calipers.
-Time could be spent better elsewhere
-There are perfectly good calipers available off the shelf
-Off the shelf stuff is more reliable

Rich

Cardiff Uni
FS Team Manager

[John Gregor]

That says a lot about formula student.

[Big Daddy]

Isn't the idea to build a reliable, high performing race car for a realativly low cost? Then why not use an off the shelf 4-8 piston caliper. http://fsae.com/groupee_common/emoticons/icon_rolleyes.gif

[Matt Gignac]

Also, the presentation judges like it when you use readily available parts that can be purchased in bulk instead of doing a run of 500 parts

[Charlie]

Can someone tell me where all these great off-the-shelf, cheap, lightweight, 4-8 piston calipers are? We have been caliper searching for 2004 and are having a really tough time finding something that meets our criteria. I think there are definite benefits in making your own caliper, there isn't an excellent answer for us readily available that we have found. (There are 'good enough' calipers not great ones).

I definitely think making your own caliper can be a big advantage in terms of packaging, which can affect big parameters in your suspension design.

-Charlie Ping
Auburn University FSAE (http://eng.auburn.edu/organizations/SAE/AUFSAE)
5th Overall Detroit 2003
? Overall Aussie 2003. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Brent Howard]

I really think the comments I posted in the ECU vs. dynojet article apply here as well. And I mostly agree with Charlies comments about diminishing returns. Every single part on these cars must be looked at and the best solution should be found based on more than just one design parameter (cost, performance, reliability, manufacturability, and of course deliverability)

http://fsae.com/eve/forums?a=tpc&s=763607348&f=125607348&m=7466091234

Brent

www.ucalgary.ca/fsae (http://www.ucalgary.ca/fsae)

[Scott Wordley]

I agree with Clausen, go off the shelf, your efforts are probably better spent elsewhere.
The only major difficulty we found with most bike calipers is that they usually have radial plumbing which is not ideal for stuffing inside a 13" rim, but easily solved with a small modification. The 4 pot brembos we've used in the past have been great, and we too have won the Brake award against several teams with homemade calipers.

As for "they look sweet!", Carbon wishbones look sweet too but I'm not rushing to make any

Regards,

Scott Wordley

http://www-personal.monash.edu.au/~fsae

[gug]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by John Gregor:
This is a design competition. It is not about just buying a whole bunch of parts off the shelf and bolting them together.<HR></BLOCKQUOTE>

so do you build your own engine? machine your own block and do it the WWU way? make your own rubber compounds and create your own tires? dig your own bloody steel out of the ground?

as you well know, people decide on what gives the best return for their design effort and money. dont just outright insult someone (Neil Anderson) for having a different opinion to you. by all means, disagree with it and post up some reasons/facts. i have no doubt you could teach me something!

edit: (before i get misinterpreted again, this post is designed to get some information out of you. it is not meant as an insult. ive seen that all your other posts are quite good. and it casts no aspersions on safety at the event. http://fsae.com/groupee_common/emoticons/icon_biggrin.gif )

- if it isnt coming, you need a bigger tool.

[This message was edited by gug on October 02, 2003 at 12:03 PM.]

[Brent Howard]

I think it is quite unrealistic to expect a group of say 15 students to completly design and manufacture every part on a race car within a year. Specing out parts is a HUGE part of engineering. I don't think that the engineers at Ford, Gm, and Chrysler design custom parts for every single vehicle they manufacture. They use out sourced parts and build around that. If there is a part that they can justify producing in house then they do it. Saying that you must design your own calipers, diff, throttle body, etc... is like saying that you must design each bolt, nut, and fastener to take the exact amount of applied stress. Like Charlie said, take the problem and stop designing when you have reached a point of diminishing returns.

Brent

www.ucalgary.ca/fsae (http://www.ucalgary.ca/fsae)

[Sam Zimmerman]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by John Gregor:
This is a design competition. It is not about just buying a whole bunch of parts off the shelf and bolting them together.

That says a lot about formula student.<HR></BLOCKQUOTE>

I believe the premise of the competition is to design a prototype car that will be manufactured by a different firm with the end user being a weekend autocross racer. With that in mind, the ideal car would have all "off the shelf" components so the end user would have replacement parts availabe.

Having all "off the shelf" components is about as reasonable as having all custom fabricated parts, however, but a mix of both based on rational engineering judgement seems to follow the premise quite nicely.

I am of the opinion that teams that make their own ECU's, have carbon fiber chassis and the like should be docked in the design event because they have failed to design to the premise of the competition. The real beauty in the great designs I saw last year are the simplicity, innovative packaging, and manufacturability.

Sam Zimmerman
Vandals Racing (http://www.uidaho.edu/~racing)

[Sam Zimmerman]

By the way, we are looking into designing our own brake calipers this year because of packaging issues. http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

Sam Zimmerman
Vandals Racing (http://www.uidaho.edu/~racing)

[James Waltman]

2.3 VEHICLE ELIGIBILITY
It is the intent of the SAE Collegiate Design Series Competitions to provide direct hands-on experience to the students. Therefore, students should perform all fabrication tasks whenever possible.

I think that this is an engineering and design competition first and foremost. The weekend autocross racer goal is just something to give us direction. So I think that schools should design and manufacture as much as they can for themselves. I do realize that many teams don't have the facilities to make calipers so then there might not be an option...

Our brake design doesn't really allow for off the shelf calipers. Besides, we couldn't afford any even if they were available.
http://dot.etec.wwu.edu/fsae/v30/image024.jpg

To answer Bryan's question that started this topic: In the past our calipers have had holes that transferred fluid between the pistons. The holes were made with an EDM. I'll see if I can get a picture of the holes posted but it might take a while.

James Waltman
http://dot.etec.wwu.edu/fsae/
Vehicle Research Institute at
Western Washington University

[Scott Wordley]

James,

Thats some awesome work. I would hate to see teams discouraged from attempting trick components like this, along the lines of Sam's proposed design event block.

Neat brakes/uprights aside, are those rod ends in bending?

Regards,

Scott Wordley

http://www-personal.monash.edu.au/~fsae

[James Waltman]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Scott Wordley:
Neat brakes/uprights aside, are those rod ends in bending?<HR></BLOCKQUOTE>

No, but it may look like that way because of unfortunate lighting conditions.


That is a picture of Viking 30's setup. This is some of the trick stuff that gets overshadowed by the V8. You can't tell in the picture but the uprights are actually hollow. The picture does show the unique orientation of the calipers. This is the same basic setup that we are using on the current car, Viking 35. Mike Waggoner did the most recent uprights and calipers and did a fantastic job. We will start the first steps of fabrication on a new set tomorrow that should be pretty trick.

Sorry, I tried to post some pics that show how they are hollow but I am having trouble.
You'll have to follow the links if you are interested:
Viking 35's current uprights –
open (internal) (http://dot.etec.wwu.edu/fsae/v35/bonding/pages/Upright%20-%20Inside%20both%20halves%20at%20once_JPG.htm) and
then closed (external). (http://dot.etec.wwu.edu/fsae/v35/bonding/pages/Upright%20halves%20bonded%20together_JPG.htm)



James Waltman
http://dot.etec.wwu.edu/fsae/
Vehicle Research Institute at
Western Washington University

[This message was edited by James Waltman on October 02, 2003 at 11:51 PM.]

[MikeWaggoner at UW]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Scott Wordley:

Neat brakes/uprights aside, are those rod ends in bending?
<HR></BLOCKQUOTE>

Um yeah, they are. They're sized for strength and we've never had a rod end failure with regular replacement, but it is something that could have been improved with the A-arms.
I personally don't think the rods ends at that end being in bending are that signifigant. With the short lever arm and comparative length the deflection caused by them is nil. The ease of fabrication and adjustment may make up for it. However, the judges don't like it so it's a bad idea.

-Mike Waggoner
WWU Alum, UW Current

[John Gregor]

Its good to see i got people talking.

"This is a design competition. It is not about just buying a whole bunch of parts off the shelf and bolting them together." is actually a direct quote from the late Carroll Smith. He made it a clear point in one of his last design debriefs.

My comment about formula student was based on the fact that the design judges actually gave first place to a car that had never run before. A car that hasn't run before the comp has no chance of getting into the semi finals in any other comp and would be lucky to get 90 points.

About design your own brakes. It is an order of magnitude harder to "design"� your own brakes then to just buying them. And I guarantee you will learn 10 times more about brakes.

With student designed brakes you can achieve much better packaging in the wheel, and more optimum suspension geometry because of that. You can also have a lower unsprung mass as well.
You don't have to have to have super complex 6 piston ones like say RIT. You could do simple single piston calipers that could be made on a manual mill.

Looking at the photo above there is no point designing your own calipers if you have rod ends in bending and really bad load paths. Get the simple stuff right first.

I know one thing that the weekend auto crosser does want, and that is a fast, well designed and reliable car. If I was going to buy an sae car to autocross there aren't many I would buy. The ones that I would look at the most are the ones from the design finals.

[James Waltman]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by John Gregor:

Looking at the photo above there is no point designing your own calipers if you have rod ends in bending and really bad load paths. Get the simple stuff right first. The ones that I would look at the most are the ones from the design finals.<HR></BLOCKQUOTE>


John,
The photo above is from a car that was in the design finals – even with rod ends that are clearly in bending.

James Waltman
http://dot.etec.wwu.edu/fsae/
Vehicle Research Institute at
Western Washington University

[Steve Yao]

I don't believe that ordinance 2.3 encourages you to fabricate EVERYTHING; whether off-the-shelf components are available or not. Rather, that when students do have a part that can't be bought and requires fabrication, that they try to do it themselves instead of outsourcing.

When/If you get hired into industry, they will frown upon you specifying all custom parts. A design competition does not mean you should design everything. It means you create the best solution to the problem. That solution may or may not include custom parts.

FSAE is a kind of limbo between industry and university. We can use custom stuff and not take a big hit, but you wouldn't be doing the same in industry. I'd say if you really dont have anything better to do, design to your heart's content.

BTW, how is this Brake award judged? All cars are required to lock their tires, so I am unclear on what exactly is compared.

-Steve Yao

[Charlie]

Mr. Gregor what University did you attend/are attending?

I have a really hard time when people criticize other's cars when they don't even let us know where they came from. http://fsae.com/groupee_common/emoticons/icon_mad.gif

-Charlie Ping
Auburn University FSAE (http://eng.auburn.edu/organizations/SAE/AUFSAE)
5th Overall Detroit 2003
? Overall Aussie 2003. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[John Gregor]

i have been out of uni for a couple of years. i don't want my opinions to reflect on the current team.

[fsae_alum]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Charlie:
Can someone tell me where all these great off-the-shelf, cheap, lightweight, 4-8 piston calipers are? We have been caliper searching for 2004 and are having a really tough time finding something that meets our criteria. I think there are definite benefits in making your own caliper, there isn't an excellent answer for us readily available that we have found. (There are 'good enough' calipers not great ones). <HR></BLOCKQUOTE>

Try Kelgate calipers from England. They make 6 piston ultra-lightweight Enduro kart calipers. Enduro karts are not that much lighter than FSAE cars and stop from 140mph to zero real fast with these calipers with NO problems. had guys tell me that when braking from 120 to a full stop on a straight, they have almost been catapulted over the steering wheel. Just a thought!!!

In spite of...

[PatClarke]

Scott, to follow on from your light critique of the pictured front end, when I put my 'Judges' hat on, there are several areas of design on this front corner that I would like to discuss with the designer to hear his rationale.
Apart from rod ends mounted in bending, and single shear (The thread exposed on that vulnerable upper rod end scares me). The scrub radius looks to be somewhat over 100mm, and a significant amount of KPI is in there, probably to offset the scrub. There appears to be no positive locking on the critical upper KP Allen Bolt, apart from tension and some tie wire. The load paths through the upright are 'interesting', especially the cantilevered caliper mount.
Finally, mounting the rotor directly to the wheel rim must make for some interesting variations in tyre temperature as the rotor heat soaks into the rim.
It does look pretty though =] but 'pretty' does not win design.
PDR

Rudeness is a weak mans imitation of strength

[Kevin Hall]

Suddenlee

Might I ask what the difference is between the heat passing straight from the rotor to the rim, and passing through the rotor and hub to the rim?

Just a thought. I know that creates a bit more area, but with testing, at may create better tire heating, allowing for harder compounds.

Kevin Hall
University of Saskatchewan
'03-'04 Team Director

[PatClarke]

Hi Kevin,
Heating a tyre does far more than softening the tread compound (If it does do that). The increased pressure inside the tyre changes the tyre's spring rate and its response ability.
I think it is a very poor solution to making the tyres work. I would look for tyre pressure stability, and choose a tread compound to work across the entire event.
For example, if brake heat is required to make the tyres work, how do you expect to perform in the skidpad event?
PDR

Rudeness is a weak mans imitation of strength

[Jackson]

Suddenlee;

Is tie wire not considered "positive locking?"

I quote 3.7.2.2 on pp 42 of the 2003 rules:

"Positive locking mechanisms include: -Correctly installed safety wiring, cotter pins, Nylon Lock nuts and Prevailing Torque lock nuts."

Seems as if safety wire is fine as per the rules. How would you have solved the problem? Mounting a nylon sleeve at the bottom of the hole? I don't see any other way of positive locking if you have a machined hole in a custom part.

Looking at that design though... How do you change a tire? you would have to take the brake caliper off correct? Yikes. The scrub radius is HUGE (with very little KPI angle to compensate from what I can see), although if it is drivable then I don't see any major problem.

Now for the questions:

Why is the Scrub radius so large? It seems that there is at least 1-2" of extra length in those caliper mounting pins.

Here comes the praise...

The pullrod mount on the top a-arm is SWEET though. I didn't even notice it until I looked at the picture really hard. I like the sleeves at the end of the a-arms too. That would be a really cool way to avoid massive a-arm jigs that we always end up building.

Brian
Washington State U

[PatClarke]

Hi Jackson,
Of course the tie wire solution is legal, but tie wire does very little to secure a fastener, especially where that fastener is in single shear and may flex a little. I guess it will assist in preventing the fastener from falling out if it does loosen.
Your comments about the pullrod mount is valid, but the cardinal sin on this design is that upper rod end where the vehicle loads as well as the brake torque loads are being reacted through the threaded shaft of that upper rod end. This car may have made it to the design semifinals, but it didnt come through my judging line.

How would I have done it? I assume you mean what would I have done to make this solution work?
Well, simply, I wouldn't have done it like this. Sometimes an enormous amount of time and effort is wasted trying to make a silk purse from a sow's ear, when the correct solution would be to get some silk (or a man made alternative) http://fsae.com/groupee_common/emoticons/icon_smile.gif
I'm going shopping now
PDR

Rudeness is a weak mans imitation of strength

[ben]

For all the judges hyperbole, things like this always happen. To our dying days we at Birmingham will never understand how we were beaten in the FStudent design event by Bath Uni who's car sported front rocker pickups in the middle (not near the end - bang in the middle) of an unsupported tube, and Toronto who have a lot of single shear upright mountings.

A general request from me to the judges would be don't be so Black and White in debriefs if you ain't going to judge based on it.

Ben

University of Birmingham
www.ubracing.co.uk (http://www.ubracing.co.uk)

[PatClarke]

OOOoooh Ben, I hope thats not aimed at me? http://fsae.com/groupee_common/emoticons/icon_wink.gif
PDR

Seriously, you are right. In the US comp this year some cars got to the semis that shouldn't have been there, and some cars should have been there that weren't. Sometimes the reasons may not be so obvious to bystanders. F'rinstance, a very well engineered and very fast car came through my lane, yet didn't make the semis. They were very upset because it was not hard to argue that their car was better than those that did. The reason they didn't make it had nothing to do with the car, but everything to do with the lack of understanding of the students who presented it. Sometimes the problems are closer to home than you think.
In the Aussie comp over the past few years one very good team had difficulty getting the judges to take them seriously. I think I have convinced them that personal presentation and a professional might do the trick.
In the design event, your presenters need to establish rapport and communication with the judges and need to understand not only what the team have done, but why it was done. Maybe thats what happened you in previous years. I recall having a similar discussion with your team after the 2002 UK event when we were discussing where the 15 points between your car and RIT and GT went.
PDR

Rudeness is a weak mans imitation of strength

[murpia]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by ben:
For all the judges hyperbole, things like this always happen. To our dying days we at Birmingham will never understand how we were beaten in the FStudent design event by Bath Uni who's car sported front rocker pickups in the middle (not near the end - bang in the middle) of an unsupported tube, and Toronto who have a lot of single shear upright mountings.
<HR></BLOCKQUOTE>

Maybe because the overiding criteria for Design Judging (at Formula Student at least) is for the team to demonstrate sound engineering reasoning for their design decisions, backed up by appropriate calculations and test results?

This also explains the Delft result this year which has been criticised: The car was a completely integrated concept, every feature on the car was well executed, well manufactured, and resulted in a very light car. Most importantly these facts were well presented by the team to the judges.

Ian

[ben]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by murpia:
Maybe because the overiding criteria for Design Judging (at Formula Student at least) is for the team to demonstrate sound engineering reasoning for their design decisions, backed up by appropriate calculations and test results?

Ian<HR></BLOCKQUOTE>

I await the engineering justification for putting 25% of the cars mass through the middle of an unsupported tube.

If you ask me there is no justification and if the judges listen to bullshit (which we all feed them to a greater or lesser extent) then they need changing.

If we had more judges like Pat who seem to appreciate how we have to work on this project this might change.

Ben

University of Birmingham
www.ubracing.co.uk (http://www.ubracing.co.uk)

[PatClarke]

quote Ben: I]If we had more judges like Pat who seem to appreciate how we have to work on this project this might change.[/I]

........Awe shucks, now I'm embarassed http://fsae.com/groupee_common/emoticons/icon_redface.gif
PDR

Rudeness is a weak mans imitation of strength

[karter]

I await the engineering justification for putting 25% of the cars mass through the middle of an unsupported tube.

It may not be sound engineeeeerrriiinnnggg, but if the calculations said it would work then,,, poof,,,,, tada!!!!!! good enough.

[ben]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by karter:
I await the engineering justification for putting 25% of the cars mass through the middle of an unsupported tube.

It may not be sound engineeeeerrriiinnnggg, but if the calculations said it would work then,,, poof,,,,, tada!!!!!! good enough.<HR></BLOCKQUOTE>

Last time I checked the design event was about sound engineering. I firmly believe that it is irrelevant what gizmos the car may have, if the fundamentals like nodal loading of structures and double shear fastening aren't followed.

Call me old-fashioned but, having spent 18 months in the aerospace industry during undergrad placements, it does matter.

Ben

University of Birmingham
www.ubracing.co.uk (http://www.ubracing.co.uk)

[Charlie]

Couldn't agree more with what Ben is saying. It reflects Pat's view also (silk from a sow's ear). Just because you can do it that way, and the numbers work out, that may be engineering in the sense that you can prove it works. It is not GOOD engineering, especially not to be rewarded with high honors. (I have not seen the Delft car, so my comments do not reflect it).

However sometimes monumental overall acheivements can 'make up' for some oversights. Like WWU's V8. Or Delft's lihgtweight. Surely these acommplishments are worthy of note. When a team has created something no other team has, they will get attention and credit.

Aesthetics play a HUGE role as well, even if the judges don't fully realize it. If they look at a car, or a subsystem, and it is absolutly brilliantly fabricated or assembled, they will (subconsciously or not) connect that feeling with it's design. They will assume that the meticiulous preperation and attention to detail that went into the exectuion of the design also was present during its creation.

If this seems unfair, lets face it, this is how business and life works. You need to present your car and your ideas to the judges better than almost anyone else to even have a shot at the finals. In the 'real world' it is all about presentation as well. The judges are only human and they will react to good salesmanship like anyone.

That said I would agree that is is an absolute TRAVESTY that a winning 'design' is one that is totally untested in its final form. The contest is to design & build a racing vehicle to compete with others for top honors. I am not saying I don't respect Delft's efforts, however they should not be rewarded without meeting the basic goals of the competition. In 2003 I told my team (when we were running behind schedule, sound familiar?) that I would consider our effort a failure if we showed up with the prettiest slow car in Detroit. You can be damn sure, that if we took our 2 months of testing, and used it in the design stage, our car would be lighter, better integrated, and still a complete and utter failure if we did not compete.

The design event and dynamic events should not be seperated by some invisible barrier where the best design has nothing to do with on-track results. This sends the wrong message to students, it says that the two don't mix, and I belive that they should (and usually do) in real life.

You don't go to the gym and work out, bulk up, and proclaim yourself the best football player ever. You have to practice, hell, you have to learn the game first!!

These are my opinions only and not necessarily reflective of my team...

-Charlie Ping
Auburn University FSAE (http://eng.auburn.edu/organizations/SAE/AUFSAE)
5th Overall Detroit 2003
? Overall Aussie 2003. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[fade]

so then who's gonna design some spiffy drum brakes? http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Scott Wordley]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by ben:

If we had more judges like Pat who seem to appreciate how we have to work on this project this might change.

Ben

University of Birmingham
http://www.ubracing.co.uk<HR></BLOCKQUOTE>

Hahaha.....

Perhaps that should read "if we had ANY judges like Pat" because Pat isn't actually a design judge, well at least not in Australia.

Pity we realised this AFTER last year's design event.

Regards,

Scott Wordley

http://www-personal.monash.edu.au/~fsae

[PatClarke]

Scott, a word of explanation might be in order. I am the Technical Advisor to all teams competing in FSAE-A, so it would be totally improper for me to be a judge on a car I had advised on. This is why I excluded myself from judging in the semis and finals in Pontiac once UOW had made the cut.
PDR

Rudeness is a weak mans imitation of strength

[karter]

Why are some things like single shear "bad engineering"? Seems to me that a weak point is a good thing, hit a curb and change a bolt. With double shear, hit some thing and rip the mounts and control arm up but the bolt is still fine ,,,,,, so back to the pickup in the middle of an unsupported tube.

PS I know about don't hit anything, certinaly in an autocross, but look at a sprint car, single shear, grade 5 bolts,,,, saves a lot of time when they flip ...

[Charlie]

What kind of engineering did you study?

If you design a weak 'breaking' point intentionally it is a good thing, if it is 'just there' and you end up trying to rationalize it, that is stupid. I see no reason to build any kind of 'fuse' into an upright design on a FSAE car.

-Charlie Ping
Auburn University FSAE (http://eng.auburn.edu/organizations/SAE/AUFSAE)
5th Overall Detroit 2003
? Overall Aussie 2003. http://fsae.com/groupee_common/emoticons/icon_smile.gif