Will my Fire Extinguisher Mount pass Scrutineering?

[green_comet]

Hi everyone,
I have put a fire extinguisher in my car earlier today. Its your basic car powder extinguisher, with metal mounting bracket.

I have mounted it infront of the passenger seat, with a piece of carbon fiber i had laying around. Will this be able to pass scrutineering? I dont know if i should change the mount to metal plate, or just leave it as carbon fiber.

Heres a couple pics.

[Russellb]

Cams manual says it has to be serculy mounted . So if it dosn't more to much when given a good shake it should be fine . but it can come down to the scrutineer's opinion

The mount looks great . I love carbon fibre , always look's the part

[green_comet]

Thanks, i think it looks alright, i didnt noticed that the bottle wasnt sitting strainght untill i posted up the pictures.. So i have since fixed that problem...

[Bevan]

How strong is carbon fibre? I'd think with a 1kg piece to metal sitting on top that it would shatter under the load of accident.

I don't actually know this, I'm just speculating

[CT]

How strong is carbon fibre? I'd think with a 1kg piece to metal sitting on top that it would shatter under the load of accident.

I don't actually know this, I'm just speculating

Very strong. Obviously depends on a number of things like cloth weight, weave and % of resin etc etc, but yes, very strong.

[green_comet]

yeah i can shake it around pretty hard and it just moves....

[bigdog]

Some changes either in or coming in next manual (don't have a copy of this year's yet) - apparently mount must withstand a force of, wait for it, 25G's! Some total numbnut in CAMS has decided that they just ain't safe enough as they are. I can just picture the poor scruitineer trying to test this - attach chain to mount, attach other end to Mack Prime Mover, drop clutch, accelerate to 160kmh..... I am fairly sure this would only apply to logbooked cars, but then you never know with CAMS.

[Snowie]

Bigdog, 25Gs is okay so long as the duration is short. I was involved in the Huon Class Minehunters and we had to design to **G (sorry can't say, but more than CAMS anyway.)

What I am saying is that a number is useless unless it is coupled with a pulse profile or at lest a ISO Standard or similar (we used a US military spec and then trialled it with 2000 lb bombs off Newcastle ). Not to mention which direction or all and considered in component or combined.

Cams need to take a good hard look at themselves and stop being a bunch of people with a little knowledge making decisions that just makes it hard rather than safe.

Just look at the way roll bars are considered, ie if fitted and not high enough for example the car is rejected, but if then taken off, the car passes. Surely this is not quite right.

So far as carbon fibre - it looks okay, but under a shock load in the orientation and the nuts/screws used it will tear out fairly easily, cos you are relying on the interlaminar shear and bearing strength (low and resin dependant) rather than the tensile strength of the carbon (high and fibre dependant). Sure it is stiff, but it is not 'tough' like steel and cannot absorb shock loads of a tearing stress. So me personally I would change it.

Carbon kevlar on the other hand would be better...don't have any of that laying around do you.

Sorry to get all engineering on you...but it may be better to reconsider it now, rather than 20 minutes before a meeting, when you get rejected. Mind you most scrutineers wouldn't know about its capacity and that if they take more than a cursory look anyway. Have a back up if nothing else.

Okay that's enough. Sorry

[rain902]

couldnt have said it much better myself - i remember a fellow going off @ me coz i mentioned to him that self tapper screws holding his fire extinguisher into his plastic centre console was not what i considered "securely mounted"

***

sure, cams goes on and on etc in an attempt to both avoid lawyers and employ lawyers, but if we apply the theory of "look out for #1" we realise that we dont want a 1.5kg missile kicking around the cockpit with us sitting in it!

me? i have 8mm bolts holding mine to the floor, but I have no carpet...

[rain902]

i shall be more than happy to terrorise your fire extinguisher mount bright and early at round #7 if you are coming...

[npn4875]

Here's mine.

I shaped the "ears" with a bit of welding and grinding and have it mounted over the runners rather than under. And painted itblack to be a bit less conspicuous.



It doubles up as a very good floor mat retainer

Restricts the seat forward movement a bit, but as somebody said, it's never been in any other position but right back.

[JBT]

25 G . I assume that's longitudinallly. I don't think the human body can survive 25G longitudinally, so who cares whether the firex mount does.

[rain902]

25 G . I assume that's longitudinallly. I don't think the human body can survive 25G longitudinally, so who cares whether the firex mount does.

remember that helmet standards thread we had a few months ago? some of the impacts on helmets (as measured inside the helmet) were in the vicinity of 300G!

apparently doctors arent expecting full survival at over 200G impacts...

[Benny]

Don't forget that in a high speed impact, you can generate well over 100g's, so a 25G test doen't even come half way to representing a severe high speed crash.
I think they're going easy myself.
A good steel bracket bolted to the floor, with the extingisher mounted securely to it, should be able to withstand 100G, which would work out to a force of 300kg's if the unit weighs 3kg.

[rain902]

Thanks for that. I'll ask them on Monday if they have any.

ask about two of em - have a funny feeling that i will be seeing the track in my -5 fairly soon...