Carbon Fiber Rollcage

[herr_oberst]

Wow. An impressive weight savings, to say the least.


Porsche Carbon Fibre Roll Cage & Roll Bar - Porsche 997 Roll Cage - Porsche 996 Roll Cage

[widebody911]

It would probably be cheaper to make it out of rolled-up $100 bills!

[skinnerd]

Yeah.....super slick.

Wonder if SCCA or PCA will approve it?

Also what happens to carbon fiber in the case of a massive shunt?
Metal will deform or bend, and still protect to some extent.
Will carbon fiber do the same?
Or splitter/shatter? Into very sharp shards or jacked edges?

[Jim Richards]

They claim it's anti-shatter. Amazing what lengths we go to for weight savings.

[RPKESQ]

It will not like fire for as long as steel, so hope for fast help.

[onewhippedpuppy]

Interesting. Carbon doesn't deal well with impact, I wonder how it holds up. Surely there's some pretty serious testing to back it up?

[gr8fl4porsche]

This months Excellence has a write-up on the cage and some other goodies by Oakley Designs on a GT2.

They have addressed the impact and fire issues.

[Tim Hancock]

I don't like it (not that it matters). I have a buddy whose son races 700 hp dirt track cars. If the steel tubing gets damaged you simply weld in a new section... good to go again. If this carbon cage gets stressed in a minor track incident, one may never know for sure if it is still sound. Steel tubing is pretty easy to inspect, composite structures..... not so much.

[Noah930]

Originally Posted by onewhippedpuppy

Interesting. Carbon doesn't deal well with impact, I wonder how it holds up. Surely there's some pretty serious testing to back it up?

I'm no engineer, but that's what I've heard, as well. I think I'd let a few other racers test its crashworthiness before I'd select CF over steel in this application.

[serge944]

Luckily for most of us, our wallets will be doing the deciding. I can't imagine the price will be accessible to the average track junkie for a long time. ...until China starts making it.

[gtc]

I'd use it. I've been riding a carbon fiber mountain bike for years.
I'm a little surprised this is the first such cage (though I suppose you could argue they were precluded by carbon monocoque vehicles like the enzo and carrera gt).

*Single bars can be replaced in event of impact

[RWebb]

TUV Approved & FIA Approval applied for - so I guess I'm not too worried re shattering.

re cost - the more stuff that is made from CF, the cheaper it gets. expect it to trickle down thru the various "lesser" race classes and eventually...

[island911]

a pound of Steel will take more abuse (absorb more energy w/o breaking) than a pound of CF.

I could understand CF for F1, where you cannot afford the bending steel (w/o bodily contact) but for a 911? ...a few inches of deflection/energy absorption . . . I would expect would be better than a super stiff CF cage.

Wasn't it the 1930's where race cars were killing drivers because they were too stiff?

[porsche4life]

Try ~2000 with Dale Earnhardt... The force of the impact just kinda turned his insides into mush....

[island911]

Just another thought.

It could well be a carbon/aramid hybrid. --just sold as CF.

[onewhippedpuppy]

I don't like it (not that it matters). I have a buddy whose son races 700 hp dirt track cars. If the steel tubing gets damaged you simply weld in a new section... good to go again. If this carbon cage gets stressed in a minor track incident, one may never know for sure if it is still sound. Steel tubing is pretty easy to inspect, composite structures..... not so much.

Most requires non-destructive inspection (NDI), unless the damage is serious enough to be externally visual. Think they can do that in the pits?

[Steve W]

Carbon fiber is only strong in tension along the axis of the fiber, and like a rope has no compressive strength. So for a cage, you can expect the same under the compression impact of a crash, no where near the strength or energy absorption of steel. Visualize that most of the fibers in a roll cage under compression or impact will be placed under compression like pressing on a rope, or a bending moment like a fishing pole, and you can see that it would not work.

Take note though, there have been issues with with Oakley recently:
"Oakley Design" experience...please read! - 6speedonline.com Forums

[Noah930]

Steve, that's part of my understanding, as well. I have no CF fabrication or design skills. But I've understood CF to be strong in only certain axes (depending on how it's laid). I don't know if you could weave a roll cage to anticipate every possible type of vector that might be involved in a big time crash. Not saying it's impossible--just difficult. And impressive if the engineers at Oakley have figured it out.

[John Rogers]

Hummm, I noted they offered a "bolt in" option which puts them up there with Autopower (which I had) and also said that individual tubes could be replaced which is strange since it looks like in is in one or two pieces total? I have seen four cars with Autopower cages and roll bars with brace get rolled at Willow Springs and in all cases they were bolt in and never moved at all.

[BGCarrera32]

Originally Posted by Steve W

Carbon fiber is only strong in tension along the axis of the fiber, and like a rope has no compressive strength. So for a cage, you can expect the same under the compression impact of a crash, no where near the strength or energy absorption of steel. Visualize that most of the fibers in a roll cage under compression or impact will be placed under compression like pressing on a rope, or a bending moment like a fishing pole, and you can see that it would not work.

Take note though, there have been issues with with Oakley recently:
"Oakley Design" experience...please read! - 6speedonline.com Forums

That is true, but "carbon fiber" in the descriptive sense of the cage is a bit of a misnomer- it likely has kevlar woven in various directions and that does very well with impact (as others have mentioned)- in this case side impact.

Unless my "carbon fiber" cage was made by McLaren or a serious constructor which had some serious FEA done accounting for major impacts of key axies there is almost no way in the world I would bolt that in my car. To me it looks like carbon fiber tubes bonded to joints; the design doesn't look remotely optimized.

>>TUV Approved & FIA Approval applied for

That's like labeling something "Patent Pending". BFD.

>>Single bars can be replaced in the event of impact

Then it leads me to believe its not really working all that well as a system.

Of even more interest to me is how that cage holds up 5-7 years after being installed in a race car. Think UV degredation on the epoxy, various heating and cooling cycles... big article in Forza about a year ago about ex-Ferrari F1 cars that have been sold to private collectors- one of them broke apart at speed (Dutch Ferrari dealer's car) and it was found that the nose bulkhead area just sort of came apart on its own and after 10 years of existince wasn't up to the job of a race circuit anymore.

Carbon fiber cages make me about as leery as Rotafox wheels on the track. Probably fine for a while...