Carbon Fibre and Carbon Kevlar

[darthdicky]

the wife can't lift a pair of ladders at present before there full of mud so your argument is fundamentally floored they need to be lighter full stop.

How about letting her drive and you do the waffles

Richard

[Astro_Al]

your argument is fundamentally floored

Or even 'not applicable'...

But ali bridging ladders only weigh 10kgs (little less in fact) each? Regular sand ladders are less at about 8kgs. Anything you make will weigh something similar if it's not gonna break, and anything will gather some mud at least - I just don't see the weight coming down that much if it's going to survive any kind of serious use.

How about some kind of flexible matting - like those ones with the bars strung together on 2 bits of rope?

The problem appears when you try to make something rigid - all of a sudden it needs to support lots of different forces/bending moments/god-knows-what. If you use a flexible solution, it is just compression between it and the ground. If you use a rigid version, it inherently needs more structure to prevent it from collapsing under load, cos it's not just in direct compression.

Sand ladders are kind of in the middle as they can be bent, and then bashed straight again, but this isn't an option for composites, they lack the ductility.

Trying to be helpful, honest!

Al.

[freeagent]

[i would question the point of wrapping steel in fibre for the arms of a serious off-roader, but hey, give it a whirl.

in my opinion there is no point in wraping steel in carbon fibre, as there is nothing to gain by doing this.

CF is mega strong in some applications but inherently weak in others, it would be useless for landy track rods as its impact strength isn't always very good.

i would agree with Al that the design of the ladders is as important as the material.

CF is a magic material, but in some applications little better than GRP, it depends on re-enforcement orientation, matrix material, lay-up method, the interaction between the matrix and the re-enforcement.... etc,

you could make the ladders from CF but it certainly aint a dIY job, and i'd get someone to run some FEA on your design first, to make sure its up to it...

[jules]

Or even 'not applicable'...

But ali bridging ladders only weigh 10kgs (little less in fact) each? Regular sand ladders are less at about 8kgs. Anything you make will weigh something similar if it's not gonna break, and anything will gather some mud at least - I just don't see the weight coming down that much if it's going to survive any kind of serious use.

How about some kind of flexible matting - like those ones with the bars strung together on 2 bits of rope?

The problem appears when you try to make something rigid - all of a sudden it needs to support lots of different forces/bending moments/god-knows-what. If you use a flexible solution, it is just compression between it and the ground. If you use a rigid version, it inherently needs more structure to prevent it from collapsing under load, cos it's not just in direct compression.

Sand ladders are kind of in the middle as they can be bent, and then bashed straight again, but this isn't an option for composites, they lack the ductility.

Trying to be helpful, honest!

Al.

I HAVE CARBON FIBRE SAND LADDERS

which weigh less that a 1kg each

but they are not any good as bridging ladders I don't think you understand how much lighter they are and how important it is when competing that you run with as lighter truck as posible.

Mine were built for a race truck and now I want to use them on the challenge truck.

[Steve Hiatt]

The point of making wishbones from steel and carbon fibre is that you can make it significantly lighter than a steel only construction. Reducing unsprung weight in a safari racer is a big plus.

The reason for using the steel subframe is that you can then layer the carbon fibre on as a DIY job, it is effectively your mold. As I can get close to use by date carbon fibre FOC it would actually be cheaper.

This was the suggested route of an F1 composite stress engineer so I assume he knows what he is on about.

[Astro_Al]

I don't think you understand how much lighter they are and how important it is when competing that you run with as lighter truck as posible.

I think I can just about wrap my head around it.

My point is that in order to withstand the bending loads, you're going to add significant mass to the structure - it's easy to make a light panel which floats on top of the surface, it can be extremely thin and do it's job for virtually no mass. As soon as you ask it to support a wheel when suspended at either end, the demands start increasing and the mass goes up accordingly.

Of course I can see the point of it, I was actually trying to be constructive.

ALL I'M SAYING is that since you will only be able to save a few kilos on the structure mass (maybe 4 or 5 or so - which is clearly worthwhile), it'd be worthwhile spending a bit of time thinking how you can reduce the tendency to fill with mud etc - the contribution of which is a much greater part of the overall mass (when full), if you are looking to save as much mass as poss.

which weigh less that a 1kg each but they are not any good as bridging ladders

Right. See my point?

This was the suggested route of an F1 composite stress engineer so I assume he knows what he is on about.

What do you think I was doing sat at a computer with a crashed F1 in a box under my desk???

Of course I agree that the combo of fibre/steel can save mass - for a racer I can see the application, but my comment was for "serious offroader", by which I meant something that was likely to get bashed about on rocks / tree stumps etc - sorry for the confusion.

Al.

[Steve Hiatt]

my comment was for "serious offroader"

As in too many stickers and a winch on the front?

[Astro_Al]

As in too many stickers and a winch on the front?

That's it - you've got it.

[jules]

I think I can just about wrap my head around it.

ALL I'M SAYING is that since you will only be able to save a few kilos on the structure mass (maybe 4 or 5 or so - which is clearly worthwhile), it'd be worthwhile spending a bit of time thinking how you can reduce the tendency to fill with mud etc - the contribution of which is a much greater part of the overall mass (when full), if you are looking to save as much mass as poss.

Right. See my point?

What do you think I was doing sat at a computer with a crashed F1 in a box under my desk???

As a Civil eng I think I can design a simple bridging ladder to be strong enough with minimal folds to its structure.

Of course I agree that the combo of fibre/steel can save mass - for a racer I can see the application, but my comment was for "serious offroader", by which I meant something that was likely to get bashed about on rocks / tree stumps etc - sorry for the confusion.

Al.

but my comment was for "serious offroader", by which I meant something that was likely to get bashed about on rocks / tree stumps etc - sorry for the confusion.

Are you saying that a racer is not a serious offroader.

or are you saying that a racer is not as strong as a Challage truck.

mmmm ok what ever

[steffUK]

Hi Guys,

The stuff is already being done, see here http://www.daerr.de/bestellen/ergebnis.las...2F63ASQMi3BD05D

260 euros buys you ONE board or 1.7kg of Kevlar

cheers

Stefan

[jules]

Hi Guys,

The stuff is already being done, see here http://www.daerr.de/bestellen/ergebnis.las...2F63ASQMi3BD05D

260 euros buys you ONE board or 1.7kg of Kevlar

cheers

Stefan

Excellent Thanks

[northernchris]

Hi jules

When i was a PILBEAM RACING building a prototype SR2 24hr race car,we used honeycom alloy,this stuff would bend/give enough simler to glass fibre waffle boards but tenth of the weight. Give pilbeam a ring in the morning and have a word.The alloy honeycom combined with course grip tape would do the jog no probs.

Chris

[jules]

Hi jules

When i was a PILBEAM RACING building a prototype SR2 24hr race car,we used honeycom alloy,this stuff would bend/give enough simler to glass fibre waffle boards but tenth of the weight. Give pilbeam a ring in the morning and have a word.The alloy honeycom combined with course grip tape would do the jog no probs.

Chris

thanks.

I am looking for cost and size possible to make economically.

I have only been quoted for sheet CF but I will need to talk further to my mate but he is off work at present for the next six weeks

Can you send me the rough cost/catalogue for the new rally car odd and sods we chatted about.

[northernchris]

thanks.

I am looking for cost and size possible to make economically.

I have only been quoted for sheet CF but I will need to talk further to my mate but he is off work at present for the next six weeks

Can you send me the rough cost/catalogue for the new rally car odd and sods we chatted about.

ok juels will do,it would be worth giving them a call anyway because they always used to have loads of off cuts around

Chris

[darthdicky]

How about coating them with K******* so the mud doesn't stick to them

I can see where you're coming from here, but the main problem is getting rid of the mud on whatever design/material you use. I can normally carry two normal waffles fairly easily, yet at Slindon the other week it was a struggle for two of us to lift one once it was full of clay! A design that doesn't attract mud so much would be far better.

Richard

[Astro_Al]

Jules jules jules...

>"As a Civil eng I think I can design a simple bridging ladder to be strong enough with minimal folds to its structure."

Fascinating. And at what point did I say that you couldn't? Though since you're the guy who said: "Right so Cardon Kevlar is not a solid material", I have to say I probably wouldn't be first in line for them if you did...

>"Are you saying that a racer is not a serious offroader."

Don't go putting words in my mouth. From the outset, I've been trying to help with this. I think (hope!) that's clear if you read through the thread.

No, not at all - I knew that would get taken the wrong way, I apologise for my lack of clarity. It's a question of environments - as I said in my post, I was thinking of structures being struck / scraped all the time on rocks etc. We're talking rockcrawling vs. racing here. Obviously very different demands. I'm quite obviously not saying a 'racer' isn't a 'serious' offroader... That's the second time I've clarified it. I think it's clear.

You can call them what you like, but steel suspension arms have their place, and so do composite structures, that doesn't mean they are both applicable in all cases.

I'm done - you try to help and...

Al.

[02GF74]

How about coating them with K******* so the mud doesn't stick to them

like I said at the beginning, it is the mud clogging rather than the ladder weight, although ofcourse that helps.

Teflon coating? but that would make them hard to drive over.

What about wrapping them up in tarp or some other sheeting? Then unzip, give the sheeting a shake and off you go. Or better still some bio-degradable multiple wrappers, like the visor sheets on F1 helmets;

so use ladder, unzip, leave to decompose and repeat until you run out of covers.

off to the paternt office now....

[jules]

Jules jules jules...

>"As a Civil eng I think I can design a simple bridging ladder to be strong enough with minimal folds to its structure."

Fascinating. And at what point did I say that you couldn't? Though since you're the guy who said: "Right so Cardon Kevlar is not a solid material", I have to say I probably wouldn't be first in line for them if you did...

>"Are you saying that a racer is not a serious offroader."

Don't go putting words in my mouth. From the outset, I've been trying to help with this. I think (hope!) that's clear if you read through the thread.

No, not at all - I knew that would get taken the wrong way, I apologise for my lack of clarity. It's a question of environments - as I said in my post, I was thinking of structures being struck / scraped all the time on rocks etc. We're talking rockcrawling vs. racing here. Obviously very different demands. I'm quite obviously not saying a 'racer' isn't a 'serious' offroader... That's the second time I've clarified it. I think it's clear.

You can call them what you like, but steel suspension arms have their place, and so do composite structures, that doesn't mean they are both applicable in all cases.

I'm done - you try to help and...

Al.

Al

I did not put the idea forward for cladding steel with CF I asked about a materiel that I know little about.

Challenge condition and race conditions are very different but having competed in both racing and challenges admittedly British championship level racing and only more locally challenging but I did win on two occasions and come in the top ten on the other two event suffering with overheating and having the wife as a co-driver.

I feel I am qualified to state that a racer will suffer much bigger impacts than a challenge truck or rock crawler will while competing.

You will find the very few racing people on the forum will agree on this one.

Just think of the speeds that racer hit things at.

EG to cross a gully/rut that is about 1m wide by say 500mm deep my challenge truck would need to slow drop and power out only very sleight but the racer with its 205 size wheels, to not lose any time I would need to hit it at around 60mph + to ensure the shocks would work properly and the car would not even feel it. This is a very different driving stile and very hard on the car this is also scratching the surface of what a racer has to endure.

So CF would shatter if used on a racing truck drive train as it is too brittle.

As it would on some of the Big yank/Aus rock crawlers with there slow speed roll overs and bounces

I commented on the carbon Kevlar after Johns comment

Anyway

I wanted to try to make some of my essential accessories out of much lighter materials and some of these are not use during a event but I still need to carry them just in-case

You said it was a waste of time due to the mud that does not constitute help in my opinion.