pwned in design

[Christopher Catto]

LOL DJ Hache in the mix. Yeah I am still one crazy cat.

Just got back from Brno after free practice day one. Some nice DTMs out there for those who are into superlow front V8 engines and interiors that look out of a spaceship

Personal stuff aside, what Kyle is saying is perfectly correct (?!) since the driver just shifts the balance a bit to account for a lower min deceleration so less wt transfer. I would guess this is also linked to the springs you are running and the ride heights. Oh dear, I ve already found more ways to make the problem complex.

As for the pad modulus, I would say in something like sportscars, F1, Indy etc it would be quite noticeable. I would say even changing to a harder compound on your day car might have some effect (provided there are no air leaks in the system making your pedal already very soft.)

How noticeable is this gonna be? Ummm, I think the deformation in the hoses and the brake fluid will make up a large percentage of brake squidginess (new term for your Pi Toolbox channel). I know our FSAE car had a very stiff pedal but then we had a short travel AP master cyl and the leverage ratio was small so the pedal did not move much at all. Kind of weird. Dunno if good idea or not for the driver to brake relying on foot pressure and little/no foot travel.

Say hi to Jeff at Cranfield and enjoy your beer at the CSA.

[BryanH]

My .02 cents worth, have used many diff brands, compounds of brake pads. Modulus has a major effect on pedal travel and feel, BUT all modern race pads and more than a few road pads (eg TRW) are now carbon based and have the approx modulus of a brick - pedal moves until pads hit disk then clunks to a hard stop
His question is redundant

re Hashe"I don't understand the logic behind letting the rear wheels lock up more quickly in the wet".
In the wet if the fronts lock first you are looking at the scene of your accident.
If you can get the car to turn in, you can powerslide around the corner on the throttle but if it doesn't turn in.......
Cheers

[Christopher Catto]

so next time Claude will aks us how hard bricks are! just taking the mick, no harm intended.

I was modifying some pads the other day. Our diamond grinder cut through them like cheese. they were Citroen C5 pads.

[JR]

It is impossible to know everything about your car... therefore you prioritize your time. Questions like "what is the modulous of your brake pad material" really show a lack of quality judging in my oppinion. I realize that essoteric questions can show just how well a team knows their car, but in the limited time that we have to be judged it is a ridiculous waste of time and a slap in the face for the many hours spent on the project. It borders on the illegal when a certain well known judge offers the answers to his essoteric questions if you will only pay him to come to his seminar.

Instead the judges should ask teams questions related to the engineering decisions they made. For instance... Why did you choose to make the part that way? What performance criteria did you use to choose that design? What was your load case? How was it tested? Under what conditions would you expect it to break?

Take even the best tested and understood part of your car and I can make up some dumb question you won't be able to answer. What is the relative magnetic permeability of your frame material????? What... you didn't induction harden the frame so you don't know the answer???? I'm shocked!

[exFSAE]

Given that some FSAE drivers can't feel when wheels are about to fly off etc I'd have to think the pad modulus is probably low on the priorities

[Mike Cook]

JR, don't be too hard on the design judges...To be honest, I don't think I have ever got a bad question in 3 years of events at both Detroit and west. Sometimes I didn't quite agree with the judges and their POV but thats bound to happen..

[ben]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JR:
It is impossible to know everything about your car... </div></BLOCKQUOTE>

The best teams do, end of.

Best answer I ever got to one of my questions was "It's on the spec sheet..." the response being "that's not the point, I need to see if you know it"

Claude asking the odd team what the modulus of their brake pads is isn't going to fundamentally change the order of things. I do agree though that the installed stiffness of the system as a whole is more important :-)

Having been a student and a judge I can safely say the every team that doesn't win thinks there's a reason other than another team or teams was better than them. The intensity of the situation does funny things to us all, but I firmly believe the system we have is the most workable solution within the time constraints.

Ben

[Superfast Matt McCoy]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JR:
It is impossible to know everything about your car... therefore you prioritize your time. Questions like "what is the modulous of your brake pad material" really show a lack of quality judging in my oppinion. </div></BLOCKQUOTE>

It has been my experience that the judges ask questions that are raised by the answers to other questions. The questions get deeper and deeper until you don't know an answer and that's how they test your knowledge. Maybe SEY knew a lot about his brakes and so that was the next question. Maybe their team had found a solution to a problem that could have been more easily fixed with different pad modulus and the question was just a hintity hint hint.

Don't get me wrong, there is at least one judge that makes me want to head but the wall every time I think of his stupid-ass questions, but it certainly is not Claude and he is definitely an exception to the rule.

[VFR750R]

The brake pad elastic modulus question seems like a trick question which a few here have alluded to. He's not really asking what the modulus is, he wants you to explain that it is insignificant compared to the expansion of the calipers and lines ect.

I could imagine a judge asking an engine captain the thermal expansion of his stainless steel headers. And although its much higher then mild steel it won't change the engine tuning a significant amount.