Suspension upper limit

[Cement Legs]

For the upper limit of travel in FSAE car suspension are most teams designing the damper/spring to bottom out or the actual frame on the ground. If anyone is letting the frame touch the ground what material are you using for a skid pad. I seem to remember some F-1 cars using a specific type of natural wood in spite of all of the composite materials available.

Cheers

[Cement Legs]

For the upper limit of travel in FSAE car suspension are most teams designing the damper/spring to bottom out or the actual frame on the ground. If anyone is letting the frame touch the ground what material are you using for a skid pad. I seem to remember some F-1 cars using a specific type of natural wood in spite of all of the composite materials available.

Cheers

[Kevin Hayward]

We design our car to just miss the ground under full bump. However bumps in the track (ie Detroit) can make this not enough clearance occassionally.

To avoid ripping up the bottom of our monocoque tub we run a 5mm thick aluminium skinned aluminium honeycomb panel. The panels are very light and made by a sponser (Ayres composites) so are very accessible.

If we didn't have the bash plate we would probably run the 5mm higher to avoid damaging the tub so we don't really lose any CoG.

When we ran frame cars we just let the frame scrape if it hit. On all the cars we make sure the sump is not the lowest part of the car by a good 5mm.

Cheers,

Kev
UWA Motorsport

[EgyptianMagician]

just a quick FYI...

After experimenting with every material known to man (and maybe aliens) F1 cars still find that "Teak" wood is the best substance for preventing their nose from banging on the ground ... and it doubles as an indicator to the track offcials by leaving long yellowish marks on the race track.

cheers,

[jack]

ti is allways an entertaining material for skid plates. http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

[Chase]

I'd love to see a really thin layer of Magnesium used http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

[D J Yates]

The wooden plank on F1 cars is to limit the ride height. Because it's wood, if the ride height is too low the plank wears. If the wear is deemed to be to much by the marshals, then the car gets disqualified as a result of having too lower ride height.

At least that's the impression is was under.

For FSAE, the rules state that the suspension travel must be at least an inch either way and at no time should any part of the car (other than tyres obviously) come into contact with the ground. Since we don't have wooden planks i don't see how they can really check this when the cars out on track, but even so i wouldn't try bending these rules. I can see why you wouldn't want your spring dampers to reach full travel, but i can't see why you'd ever want the car to bottom out instead.

[Cement Legs]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Chase:
I'd love to see a really thin layer of Magnesium used http://fsae.com/groupee_common/emoticons/icon_biggrin.gif <HR></BLOCKQUOTE>

The biggest problem with hitting the frame on the ground is friction and deceleration. Do you also recommend running this thin strip of magnesium into our manifold for better "spark-under-bottoming-acceleration"? http://fsae.com/groupee_common/emoticons/icon_razz.gif

[EgyptianMagician]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by D J Yates:
The wooden plank on F1 cars is to limit the ride height. Because it's wood, if the ride height is too low the plank wears. If the wear is deemed to be to much by the marshals, then the car gets disqualified as a result of having too lower ride height.

At least that's the impression is was under.
<HR></BLOCKQUOTE>

Interresting ... but I thought that it was a material decided on by the team, and that all ride height measurements are done statically, so the the wood is to protect the car and provide minimum resistance, and acts as an indicator.

Can't seem to find a definitive article about this, oh well, I'll keep looking.

[syoung]

I'm trying to remember if the rules have changed on this in the last few years, but I don't think so. The plank was still in use in 2002 - see BBC article (http://news.bbc.co.uk/sport1/hi/motorsport/formula_one/1851664.stm).

A 10 mm thick wooden plank (I expect the FIA specify a type or, more likely, material properties) had to be fitted to the floors of all F1 cars as part of a number of changes made in reaction to Senna's death in 94. The idea was to disrupt under-body airflow. Michael Schumacher was disqualified after winning the Belgian GP in 94 for having a plank that was less than 9 mm thick (10% wear was allowed).

[EgyptianMagician]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by syoung:
I'm trying to remember if the rules have changed on this in the last few years, but I don't think so. The plank was still in use in 2002 - see http://news.bbc.co.uk/sport1/hi/motorsport/formula_one/1851664.stm.

A 10 mm thick wooden plank (I expect the FIA specify a type or, more likely, material properties) had to be fitted to the floors of all F1 cars as part of a number of changes made in reaction to Senna's death in 94. The idea was to disrupt under-body airflow. Michael Schumacher was disqualified after winning the Belgian GP in 94 for having a plank that was less than 9 mm thick (10% wear was allowed). <HR></BLOCKQUOTE>

Awesome! Thanks for the explanation.

The rules have not changed, I walked the Montreal track after the last race and there were marks galore around the bumpy areas.

Did some diggin'
F1 Technical Regulations (http://www.fia.com/resources/documents/1368441606__2005F1TechnicalRegulations.pdf)

page 10, section 3.13 ... very good to know, thanks, DJ and syoung were 100% correct.

Funny how all of these rules changed because of Senna's death, and yet none of them really contributed to his death persay, accident maybe, but not death.

Anyway, another thread debate I suppose.... mystery solved.

[B Hise]

Were running much lower this year than last, and I plan on using some simple bump stops. The car might get a little hairy if we happen to encounter bumps that will force that amount of wheel travel... but I think its better than having to bounce off of the pavement.

[BryanH]

"The biggest problem with hitting the frame on the ground is friction and deceleration"

Disqualification would be the biggest problem!

[Angry Joe]

We run aluminum sheet. It tends to get beat up after a while since our cars have to be stored in a shitty gravel lot. And yes we make sure the chassis slaps out first - just be careful with engine placement.

[Cement Legs]

Thanks http://fsae.com/groupee_common/emoticons/icon_mad.gif Joe, I figured it would be tough to bottom out the shocks first and still get the spring rates set up how and where yo want'em (no not impossible of course). Letting the bottom gently scrape in the "biggest hits" seems to make more sense to me.

Cheers

[Denny Trimble]

If the chassis bottoms out, it takes normal load away from the tires, and the car loses grip. If the shocks bottom out, the tires see a spike in normal load, which may cause the car to "dart". Neither is good, and excessive chassis dragging can get you black flagged, so we run aluminum skidplates / "indicator blocks" when setting up our chassis. We lower the car until it bottoms, then raise it about 1/8". We have some bumpy sections of our testing lot that approximate the smooth sections in Pontiac http://fsae.com/groupee_common/emoticons/icon_smile.gif

[dancin stu]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Cement Legs:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Chase:
I'd love to see a really thin layer of Magnesium used http://fsae.com/groupee_common/emoticons/icon_biggrin.gif <HR></BLOCKQUOTE>

The biggest problem with hitting the frame on the ground is friction and deceleration. Do you also recommend running this thin strip of magnesium into our manifold for better "spark-under-bottoming-acceleration"? http://fsae.com/groupee_common/emoticons/icon_razz.gif <HR></BLOCKQUOTE>

Interesting FACT time!

Completely off subject, but the first BTCC night race to be held a few years back, they put titanium strips under the front splitters so that the cars 'sparked' when hitting kerbs etc etc

all for the good of the 'show'

[Denny Trimble]

Yeah, one of the design judges in 2003 was asking about our delrin skid plates. "Why don't you use titanium?" Uhh, delrin is lighter, blah blah blah... "You ever see the sparks that come off titanium? Scare the sh!t out of the guy behind you!" How's that for data driven decisions http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Rob Davies]

Ive been looking into delrin but when I look on the dupoint website there is so many different types to chose from. What did you use?

Any reason why you wouldnt use delrin for the entire floor tray since its half the density of aluminium we currently use?


Thanks.

[Denny Trimble]

I'd say aluminum should be used as a stressed skin on your floor tray, with delrin blocks at the wear points (low and far from center). Delrin wouldn't be as efficient as a stressed skin, and if you used sheet, you'd risk wearing through at the wear points.

I don't remember which grade we used, whatever was available at www.onlinemetals.com (http://www.onlinemetals.com) (nice website, warehouse is a couple miles away from our shop).