RE: TVR to offer carbon construction
Discussion
Equus said:
It's an issue to be aware of - not a 'huge' one (as the above photo shows) - and easily dealt with.
To quote from the Gordon Murray Design's own website, "the tubes used in the iFrame are coated internally and externally with an organic autophoretic material to provide exceptional corrosion resistance". The composite panels are then bonded on using structural adhesive. Any form of corrosion-resistant paint or coating, OR the structural adhesive on its own would isolate the CF from the steel frame sufficiently to prevent any galvanic corrosion.
I think you can probably rely on Gordon Murray and his team to have the necessary experience.
This is what I meant by doing their research. The metal parts have to be isolated from the carbon fibre. The coating will have to adhere strongly with both the composite and the steel part and not allow electrical conduction.To quote from the Gordon Murray Design's own website, "the tubes used in the iFrame are coated internally and externally with an organic autophoretic material to provide exceptional corrosion resistance". The composite panels are then bonded on using structural adhesive. Any form of corrosion-resistant paint or coating, OR the structural adhesive on its own would isolate the CF from the steel frame sufficiently to prevent any galvanic corrosion.
I think you can probably rely on Gordon Murray and his team to have the necessary experience.
Edited by Equus on Friday 22 January 12:41
delta0 said:
The coating will have to adhere strongly with both the composite and the steel part and not allow electrical conduction.
Again, refer to the photo above. The conductive carbon fibres are embedded in a non-conductive matrix of epoxy resin. The steel bobbins on the car used in the photo were not treated in any way; just the adhesive used to bond them in place, along with the resin matrix of the carbon/epoxy composite, was sufficient for galvanic corrosion not to be a problem.Sorry, but you are grossly exaggerating the risk.
And were you seriously trying to suggest that a company with GMD's reputation and expertise might have failed to 'do their research'?
Honestly, what you are doing is scaremongering, pure and simple.
kambites said:
Hmm, I was thinking it's just getting less and less likely to actually happen. I hope I'm wrong.
I've expressed concern about this all along. Murray, although revered, hasn't designed and built a road car from scratch since the F1. The engine is a bog standard Coyote crate motor. You can now get that engine in a Mustang in the UK for under £35k. There's no way TVR are going to be able to sell these profitably at £70k - assuming they ever get made. Carbon isn't cheap either.Equus said:
Again, refer to the photo above. The conductive carbon fibres are embedded in a non-conductive matrix of epoxy resin. The steel bobbins on the car used in the photo were not treated in any way; just the adhesive used to bond them in place, along with the resin matrix of the carbon/epoxy composite, was sufficient for galvanic corrosion not to be a problem.
Sorry, but you are grossly exaggerating the risk.
And were you seriously trying to suggest that a company with GMD's reputation and expertise might have failed to 'do their research'?
Honestly, what you are doing is scaremongering, pure and simple.
As an expert in the field epoxy does not provide adequate protection when provide from a wet or prepared layup. Extremely far from it. They are curing the carbon onto the metal and that will be completely inadequate for galvanic protection on its own. I'm sure they have done research into applying a coating to the steel that isolates it from the CF and this must be compatible with the resin to achieve the adequate bond strength. There are ways around it and you can coat the steel tubes first with a thick barrier layer.Sorry, but you are grossly exaggerating the risk.
And were you seriously trying to suggest that a company with GMD's reputation and expertise might have failed to 'do their research'?
Honestly, what you are doing is scaremongering, pure and simple.
Edited by delta0 on Friday 22 January 14:57
delta0 said:
They are curing the carbon onto the metal and that will be completely inadequate for galvanic protection on its own.
No they're not. The panels in the iStream process are formed and cured separately, then bonded to the 'spaceframe' using structural adhesive.
At least take the trouble to form a basic understanding of the process you're scaremongering about.
Of course, under normal circumstances where you really are curing metal to carbon, you'd use an isolation layer as part of the layup. Again, well understood and absolutely standard practice
After some dozy clown drove through me recently as I was out cycling on my bike, I took the bike to the shop to be examined. The bike appeared to be intact, but the shop told me that a crashed carbon frame needs to be replaced as no-one will stand over it's post-crash strength and stability, even without any apparent damage.
Will the same logic apply to the composite chassis of cars or is the technology to repair composite products also progressing? In the case of low volume cars where future availability of spare parts for repair might be difficult, without the technology to repair a composite chassis, would a relatively minor accident to a car with a composite chassis be a show stopper?
Will the same logic apply to the composite chassis of cars or is the technology to repair composite products also progressing? In the case of low volume cars where future availability of spare parts for repair might be difficult, without the technology to repair a composite chassis, would a relatively minor accident to a car with a composite chassis be a show stopper?
howertings said:
...would a relatively minor accident to a car with a composite chassis be a show stopper?
It depends on how it's been designed, but for a road car you'd usually design fairly substantial, modular crash structures that bolt on to the front and rear.If the central tub was seriously damaged, then yes, the structure would be a write-off, but then if the central tub was seriously damaged, the driver would probably be too dead to care.
My my there are alot of handbags being flung about. I bet they can't do this, carbon is really expenvive, ooh that won't happen, how they gonna bond metal to carbon, Gordon Murray hasn't designed a road car since the F1. Getting cheap cars in many markets, won't happen.
All F1 teams and at least Mclaren have a great deal of experience putting metal on carbon fibre. Many of the cars they did this on are still running. McLaren are doing the same and are unlikely to do it, if the solution last 5 mins.
If Murray is now using a carbon tub and bonding metal to it within iStream then would it not be safe to assume, given his attention to detail, that they have found a way to avoid corrosion ensuring the car disintegrates after a few years?
Gordon Murray's last car was the Mercedes-Benz SLR McLaren not the F1. iStream is so badly thought out that Yamaha have already got on car in production and several on the way. TVR are amoung a number of companies going to use it.
The cost of carbon fibre was largely to do with the manual nature of production and the autoclave required. However it is becomeing much more a part of high volume manufacturer. Ducati use it, Lambo, Boeing, McLaren, BMW, etc, etc, etc. It should be a very simple design compared to the tub used in the i series BMW's.
Even if it is still no better than they cars Peter Wheeler and co used to put together, which it won't be then how about just a little enthusiam.
Get the feeling there are far to many Porschar owners and if a car is not backed by the worlds biggest car maker providing a parts bin, R&D and manufacturing experise then it just cannot be any good.
All F1 teams and at least Mclaren have a great deal of experience putting metal on carbon fibre. Many of the cars they did this on are still running. McLaren are doing the same and are unlikely to do it, if the solution last 5 mins.
If Murray is now using a carbon tub and bonding metal to it within iStream then would it not be safe to assume, given his attention to detail, that they have found a way to avoid corrosion ensuring the car disintegrates after a few years?
Gordon Murray's last car was the Mercedes-Benz SLR McLaren not the F1. iStream is so badly thought out that Yamaha have already got on car in production and several on the way. TVR are amoung a number of companies going to use it.
The cost of carbon fibre was largely to do with the manual nature of production and the autoclave required. However it is becomeing much more a part of high volume manufacturer. Ducati use it, Lambo, Boeing, McLaren, BMW, etc, etc, etc. It should be a very simple design compared to the tub used in the i series BMW's.
Even if it is still no better than they cars Peter Wheeler and co used to put together, which it won't be then how about just a little enthusiam.
Get the feeling there are far to many Porschar owners and if a car is not backed by the worlds biggest car maker providing a parts bin, R&D and manufacturing experise then it just cannot be any good.
Equus said:
No they're not.
The panels in the iStream process are formed and cured separately, then bonded to the 'spaceframe' using structural adhesive.
At least take the trouble to form a basic understanding of the process you're scaremongering about.
Of course, under normal circumstances where you really are curing metal to carbon, you'd use an isolation layer as part of the layup. Again, well understood and absolutely standard practice
It is hardly scare mongering. Completely over the top reaction to hoping they have done their research on this area. Even pre cured panels bonded to the steel also result in corrosion. If they have done their research and know about this issue then they will have put a good long term barrier in place. The panels in the iStream process are formed and cured separately, then bonded to the 'spaceframe' using structural adhesive.
At least take the trouble to form a basic understanding of the process you're scaremongering about.
Of course, under normal circumstances where you really are curing metal to carbon, you'd use an isolation layer as part of the layup. Again, well understood and absolutely standard practice
RoverP6B said:
Gordon Murray's last road car was the McLaren F1.
The SLR was a Mercedes-Benz project for which McLaren simply engineered the carbon bits.
I see you're up to your usual trick of stating fiction in an authoritative manner to make it seem like fact.The SLR was a Mercedes-Benz project for which McLaren simply engineered the carbon bits.
SLR was designed by GM, and he was the head of McLaren Cars at the time. It is very much a car created under his watch with Merc just providing powertrain, interior bits, and styling direction.
RoverP6B said:
There's far more of the SLR that's Mercedes than McLaren. The entire drivetrain, interior and electronics, for a start. The Rocket is a very basic bike-engined trackday special with no interior save a basic seat and controls.
Apart from having reworked most of the engine and uprated the gearbox you mean?Of course they picked off-the-shelf parts for some of the car, why build a brand new engine from unobtainium when you can modify a cracker already?
The Rocket isn't a track special, otherwise it would have downforce. It's a car designed to be as light and simple as possible, and to be enjoyed on the road.
McLaren has no powertrain department, which is why it uses a Ricardo engine mated to a Graziano gearbox in its road cars. The engine and gearbox in the SLR are pure Mercedes-AMG. The standard 5G-Tronic is rated for 1000Nm anyway, no need to uprate it... Most trackday specials (i.e. Caterham/Westfield, Ariel Atom etc) have no downforce. The Rocket was designed for track use and a shortish journey to/from the track. It has no roof, no doors, no interior, nothing to homologate, basically...
RoverP6B said:
There's far more of the SLR that's Mercedes than McLaren. The entire drivetrain, interior and electronics, for a start. The Rocket is a very basic bike-engined trackday special with no interior save a basic seat and controls.
Gnnnphh....must....resist....biting....gnnphhhowertings said:
After some dozy clown drove through me recently as I was out cycling on my bike, I took the bike to the shop to be examined. The bike appeared to be intact, but the shop told me that a crashed carbon frame needs to be replaced as no-one will stand over it's post-crash strength and stability, even without any apparent damage.
This is precisely why I avoid all carbon bike components. They look pretty in the shops, which is why they sell. But a complete waste of money if you intend to use and abuse them in real life. I prefer steel or titanium 
Gassing Station | General Gassing | Top of Page | What's New | My Stuff