28 replies to this topic

[f1steveuk]

Depending who you believe, the first use of Carbon Fibre was; the scuttle panel on the Brabham BT48, or the rear wing support on the Hill GH1, or............. but that's F1, any evidence of carbon pre these two F1 examples?

[petefenelon]

Originally posted by f1steveuk
Depending who you believe, the first use of Carbon Fibre was; the scuttle panel on the Brabham BT48, or the rear wing support on the Hill GH1, or............. but that's F1, any evidence of carbon pre these two F1 examples?

Wasn't there some on the John Wyer Gulf Mirage-DFVs a year or two before the Hill?

[kayemod]

Originally posted by f1steveuk
Depending who you believe, the first use of Carbon Fibre was; the scuttle panel on the Brabham BT48, or the rear wing support on the Hill GH1, or............. but that's F1, any evidence of carbon pre these two F1 examples?

When was the Brabham BT48, 1979? I don't remember when the first proper carbon panels arrived in F1, but the more affluent teams were using carbon reinforced bodywork at least ten years before that. What they used to specify were lighter than standard fibreglass mouldings with tows of carbon added on the inside as stiffeners, usually in a square grid pattern. On something like a McLaren M8 Can Am car, this was enough to stiffen the unsupported flat horizontal areas of the nose & tail, and stopped them deforming from air pressure. Some of the drivers weren't too keen on all this, as the stiffened carbon tows could separate from bodywork in crashes and acted like spears, but improved manufacturing methods cured that problem. The first structural use of carbon composites were parts like wing supports and endplates, but these were fabricated from sheet material, moulded composites for bodywork, and eventually monocoques came several years later.

[kayemod]

Originally posted by petefenelon


Wasn't there some on the John Wyer Gulf Mirage-DFVs a year or two before the Hill?

I saw the Wyer Mirage-DFV bodies being made, and they had a simple carbon stiffening pattern added on the inside of conventional fibreglass. I should remember when moulded carbon panels first arrived, but as I don't without checking (give me time) I'd guess at some time in the early 80s. You needed expensive car-sized autoclaves & vacuum equipment, so the capital investment put the process beyond most, at least in the early years.

[Doug Nye]

I understood that practicable carbon fibre was originated by a team at the Royal Aircraft Establishment, Farnborough here in England, in 1964 under the direction of Bill Watt. Du Pont in the US then produced Kevlar. Carbon-fibre was offered on the open market in the 1970s. Fothergill & Harvey of Rochdale made carbon-fibre pre-preg cloth. Roger Sloman was an R&D engineer there and he recognised the material's potential for racing uses. He circularised the racing industry to attract their attention. Harvey Postlethwaite of Hesketh and John Horsman of JW Automotive contacted him. But JW had first used carbon filaments as early as 1967 to stiffen ultra-thin GT40 (or Mirage???) body panels, notably around the wheel-arch edge. Sloman made wing end plates for Hesketh, then airfoils for Gulf, then the notorious Hill GH1 wing pillar was mounted I believe against his advice. Gordon Murray used flat carbon panels as partial structural elements in his BT46 chassis of 1978.

DCN

[f1steveuk]

Ah, Gordon couldn't actually remember if it was the BT46 or the BT48, but he did know they were flat panels.

As regards composites, I believe that Supermarine used a pre-preg calico based material on one Spitfire to see if thy could replace scarce Ali'

So the answer to the question really is, that carbon got in mainly through F1 and filtered through the rest of the racing world, much like Gordon using the puck type carbon brake discs?

[doc knutsen]

I seem to remember Supermarine using phenolic resin reinforced linen as an experiment during WWII, for skinning the aircraft. (due to scarcity of aluminium) Famously, the Mosquito used plywood - which is technically a composite - as did Marcos and Protos in the early Sixties. Jim Hall's Texas roadrunners used a plastic composite load bearing structure, but it was glass reinforced by polyester or vinylester iirc. Of course, Chapman had already demonstrated the viability of fibreglass load bearing structure way back in 1957, with the Elite.

[Sharman]

Didn't the Elite have metal reinforcement in strategic places?. I remember talking to the designer (can't think of his name) of the Rochdale Olympic who was very proud that there was no metal in his shell

[kayemod]

Originally posted by doc knutsen
I seem to remember Supermarine using phenolic resin reinforced linen as an experiment during WWII, for skinning the aircraft.

The Spitfire experiment did indeed use fabric and phenolic resin, a bit like a printed circuit board really, and the idea was resurrected many years later for the infamous East German Trabant. The Trabant's body panels were made of a substance called 'Duroplast', which was formed by impregnating wool or cotton fabric in female moulds, not too dissimilar from the rather higher-tech fibreglass process. Driving on West German Autobahnen after the Wall came down could be an interesting experience, East Germans were determined to exploit and enjoy their new-found freedom, but the 'Ossies' had zero experience of the way that 'Wessies' drive. It was a common experience to be steaming along an autobahn at well over a hundred to find one of these devices lurching into the outer lane right in front of you, flat out at a smoky 55 mph. The Trabi had minimal impact resistance, and there were some spectacular accidents. In the days before recirculating climate control, you didn't want to get behind one or more of these things on a twisty climb in the Bavarian or Austrian Alps.

[kayemod]

Originally posted by Sharman
Didn't the Elite have metal reinforcement in strategic places?

Not as far as I know, though Elites were before my time, and they might have been better cars if there had been more metal in them. All I remember for certain is that threaded metal bobbins were moulded into the structure as attachment points for engine & suspension. If you drove an early Elite hard, it was only a matter of time before the final drive parted company with the rest of the car. At first Chapman refused to accept that the problem existed, until an Elite with ACBC at the wheel shed it's final drive right outside the factory in Delamare Road. After that the design was improved, but once he had their money, Chapman never cared a great deal about what he put his customers through.

The Elan, Elan+2 and Europa bodies had no metal in them either, other than lots of threaded metal bobbins for mounting them to the chassis. All three also had a rudimentary structure that looked like an oversize twisted wire coathanger bonded into each door skin, allegedly for side impact protection, though really it was little more than cosmetic. Crash protection wasn't taken too seriously in the 60s & 70s, but even at the time, we all wondered how on earth Lotus managed to get away with it. Until the M50 Elite, a Lotus was never a car to contemplate having any kind of accident in, and many of the race cars had the same reputation.

[h4887]

Originally posted by Sharman
Didn't the Elite have metal reinforcement in strategic places?. I remember talking to the designer (can't think of his name) of the Rochdale Olympic who was very proud that there was no metal in his shell

I believe the Olympic has a bonded-in steel subframe to carry the front suspension

[D-Type]

The Elite used glassfibre wherever possible. Even the door hinges were a GRP ball and socket. there were the odd steel inserts, principally to transmit point loads into the monocoque.

The Elan was a different kettle of fish - it had a steel chassis and the body stiffened it.

Going back to the original query - there is a world of difference between a panel made of plastic, or resin, reinforced with carbon fibre (The principle of reinforcement goes back to the stone age and mud huts reinforced with a lattice of branches) and a fully engineered carbon fibre panel built up of layers of carbon fibre laid in the direction of principle stresses and autoclaved.

[kayemod]

Originally posted by D-Type
The Elite used glassfibre wherever possible. Even the door hinges were a GRP ball and socket. there were the odd steel inserts, principally to transmit point loads into the monocoque.

Don't mean to be picky, but if the threaded inserts on the Elite were the same as the ones used later on the Elan etc, they were threaded zinc alloy castings, moulded into the body structure.

[Rainer Nyberg]

Shadow was also an early user of carbonfibre.

http://forums.atlasf...?threadid=21166

[kayemod]

Originally posted by Rainer Nyberg
Shadow was also an early user of carbonfibre.

http://forums.atlasf...?threadid=21166

Yes, you're right about that, but it was never the 100% carbon/epoxy composite moulding we see today. It was the same thin polyester/fibreglass, reinforced with tows of carbon fibre that most of the top racing people used back then. Specialised Mouldings did the bodywork for a lot of companies, and I think all of the more affluent ones specified carbon reinforced mouldings. It was pretty amateurish stuff by today's high-tech standards, starting (from memory) around 1970 or possibly slightly earlier. SM's MD Peter Jackson told me that making Shadow bodywork was the most unpopular job in the place, black moulds, black gel, black laminating resin, and black carbon reinforcement, it can't have been easy.

[doc knutsen]

The difference between the early use of glass fibre panels with a strip of carbon weave added, and a modern pre-preg panel with a honeycomb core, is that the former were not part of the load bearing structure. The carbon was added to provide some extra stiffness to the body panels. Typically, these were made as thin (thus light) as possible, but would often be fairly flimsy for that reason. Just adding a strip of carbon does not do too much to stiffen a panel made from glass fibre. Otoh, if the carbon is draped over a rib made from lightweight foam, the effect is very different. A better (and less expensive ) way is to use a material known as Coremat, which is somewhat like a double-thickness sheet of blotting paper. If used correctly, ie as a filling material much like alloy or Nomex honeycomb between two layers of glass and resin, it will stiffen any bodywork panel to a great extent, without the need for pre-preg carbon laminates and the associated cost. It is, however, easy to saturate the Coremat with resin, thus negating the weight saving.
As stated earlier on this thread, glass fibre has been successfully utilized in load bearing structure (Elite, Chaparral) but there is a weight penalty if it is to be made stiff enough to be safe. Hall's cars reverted to alloy sheet tubs for the later Can-Am cars, while the gf tubs were used on the endurance machines. The use of multiple layers of multi-directional carbon weave in a modern composite lay-up is for reasons of load, these panels being load bearing structural members. Just like we would use different types of steel tube (in a tubular space frame) for the roll-bar, and for the sub-frame that carries the radiator. Quite a few people used tubs that had alloy skinned honeycomb sheet for the bottom halves, and carbon skinned top parts, joined at the tub "belt line".
Indycars rules did require this construction until the late Eighties or early Nineties, because it was felt that the alloy tub would crumble progressively in a crash (thus gradually dissipating kinetic energy) while not enough was known about carbon in a similar situation. Remember the early F3 Reynard tub that had the alloy floor ripped off by kerbs, and the carbon part lozenged and disintegrated. Fortunately, the superior qualities of an all-composite tub were demonstrated by McLaren in their 1981 crash test programme (also known as de Cesaris);)

[f1steveuk]

There is a world of difference between a reinforced structure and a pre preg moulding that has been in an autoclave. I believe the Hill wing support was actually cut, jig-saw fashion from a flat sheet, whereas today it's all mould lay up, plastic bags with the air sucked out and autoclaves. Structually it seems that carbon went from F1, down through the formulae.

I also seem to recall that after Piquet's Indy shunt, the biggest threat to his legs was from the carbon dust that had got into the open wounds, either because it's poisionous, or abrasive

[doc knutsen]

The use of structural carbon/kevlar/epoxy laminates has indeed gone from F1 down through other categories, which may be a bit of a worry in some of the lesser formulae. A structure damage in a carbon/epoxy tub needs to be repaired by somebody who really knows what he is doing, otherwise the whole strength of the structure may be jeopardized. It is all to easy to bodge a repair with black fibreglass...I once nearly bought a Reynard F3000 tub that had this kind of "repair" done to it, it would be potentially lethal to use.
When we are talking about second-hand racing cars in lesser formulae, there are some really strong arguments in favour of a properly designed multi-tubular space frame, from a safety point of view. Also, an aluminium honeycomb tub is fairly easy to scrutinize for any sign of bodged repair.

[kayemod]

Originally posted by doc knutsen
The difference between the early use of glass fibre panels with a strip of carbon weave added, and a modern pre-preg panel with a honeycomb core, is that the former were not part of the load bearing structure. The carbon was added to provide some extra stiffness to the body panels. Typically, these were made as thin (thus light) as possible, but would often be fairly flimsy for that reason. Just adding a strip of carbon does not do too much to stiffen a panel made from glass fibre. Otoh, if the carbon is draped over a rib made from lightweight foam, the effect is very different. A better (and less expensive ) way is to use a material known as Coremat, which is somewhat like a double-thickness sheet of blotting paper. If used correctly, ie as a filling material much like alloy or Nomex honeycomb between two layers of glass and resin, it will stiffen any bodywork panel to a great extent, without the need for pre-preg carbon laminates and the associated cost. It is, however, easy to saturate the Coremat with resin, thus negating the weight saving.

This has been an interesting discussion, but a couple of points regarding doc's post. Maybe he doesn't remember the early days of carbon reinforcement, or maybe I'm just older, but it wasn't quite as he describes it, at least in the UK. The added carbon fibre was in the form of tows, which were like pre-cut lengths of thick black string with no twisting of filaments. They were incorporated as part of the moulding process, so they were indeed an integral part of the structure, they would have been pretty pointless otherwise. Also, if done right, they were very effective in stiffening thin moulded panels for hardly any weight gain. Doc mentions carbon weave, which may have been a slip on the keyboard, but around 1970, the stuff was virtually unobtainable in woven form, and in fact for several years afterwards, also for the most effective added stiffening you'd use unidirectional not woven material. The Coremat idea was sometimes used as a more economical method of strengthening thin mouldings, but usually as a later addition, not added in the original moulding process. The two main problems with this stuff and similar materials are weight gain through resin absorbtion, and deformation of the outer layer caused by natural shrinkage of the resin, which is very difficult to avoid and almost impossible to disguise completely.

On the Can Am Chaparrals, I'd love to know more about those cars. Although very clever and very effective in the first few years of the series, I'd guess that they were rather heavy compared to the NS4/L72 Aluminium monocoques of the opposition. But then, Jim Hall's Chevys were probably more powerful that those of most of the others, so perhaps a bit of extra weight wasn't too much of a problem.

[kayemod]

Originally posted by doc knutsen
The use of structural carbon/kevlar/epoxy laminates has indeed gone from F1 down through other categories, which may be a bit of a worry in some of the lesser formulae. A structure damage in a carbon/epoxy tub needs to be repaired by somebody who really knows what he is doing, otherwise the whole strength of the structure may be jeopardized. It is all to easy to bodge a repair with black fibreglass...I once nearly bought a Reynard F3000 tub that had this kind of "repair" done to it, it would be potentially lethal to use.
When we are talking about second-hand racing cars in lesser formulae, there are some really strong arguments in favour of a properly designed multi-tubular space frame, from a safety point of view. Also, an aluminium honeycomb tub is fairly easy to scrutinize for any sign of bodged repair.

Most certainly, I'd agree with every word of that post.

[petefenelon]

Originally posted by doc knutsen

When we are talking about second-hand racing cars in lesser formulae, there are some really strong arguments in favour of a properly designed multi-tubular space frame, from a safety point of view. Also, an aluminium honeycomb tub is fairly easy to scrutinize for any sign of bodged repair.

There is no reason for F3 cars to be carbon, other than the 'arms race' in the late 80s (which, bless him, Ron T tried to keep out of as long as he could). The FIA could quite easily step in and mandate honeycomb monocoques tomorrow on safety and cost-control grounds, if they wanted to -- but would Dallara claim that it was restrictive practices? ;P

Hey, it might even open up F3 to people who can't afford their own autoclaves... imagine that, an F3 grid with more than two marques on it!

[antonvrs]

Would any of you care to comment on the failure of Fritz Kroymann's(sp?) 2 or 3 year old Ferrari F1 at the '04 Monterey historics?
Photos showed the front third of the car sheared off cleanly at a bulkhead roughly at the driver's knees and I was amazed at the lack of discussion about this failure. Is the car designed to separate this way?
Is this considered to be a safety factor? Or is it an indication that these are disposable chassis to be used for one season and then tossed?
Apparently this car was maintained/prepared by Ferrari's client service department at considerable cost to the client.
Anton

[Doug Nye]

GULP! Cough - splutter.... S'cuse me while I choke on my cup of tea! That's a whole new thread there...

DCN

[antonvrs]

Sorry, the carbon fiber aspect triggered that.
I'll repost it on another forum.
Anton

[antonvrs]

And, the Ferrari WAS running at a "Historic" event.

Anton

[Cirrus]

There is no reason for F3 cars to be carbon,

If you read the FIA regs for F3, it's quite clear that they see F3 as a "carbon" formula. Ron Tauranac and I worked on a low-cost club racer design a couple of years ago, and we based the safety requirements on F3 - it was all sensible stuff, but the regs weren't conceived around the folded aluminium design that we had in mind.

Ron T designed a car in the early nineties for the Honda Racing School at Suzuka. It was an aluminium honeycomb car with a very novel construction method which would have allowed the cars to be shipped in "flat pack" form (Ikea syle) for assembly in Japan. The cars were eventually built in the UK and shipped to Suzuka ready to run. Honeycomb panels remain a very viable material for chassis construction - probably much cheaper to produce than the complex spaceframes currently seen in FF.

[petefenelon]

Originally posted by Doug Nye
GULP! Cough - splutter.... S'cuse me while I choke on my cup of tea! That's a whole new thread there...

DCN

Yerrrs, I recall starting a thread on it the week of Kroymans' accident ;P

[petefenelon]

Originally posted by Cirrus


If you read the FIA regs for F3, it's quite clear that they see F3 as a "carbon" formula.

Indeed, but there's no reason for it! and it seems to be one of the things making F3 a disgrace to watch and a ripoff to take part in! I could quite easily see F3 at a national-championship level dying within the next 3-4 years unless something fairly radical is done to it, both from the point of view of addressing the ludicrous imbalances between downforce, mechanical grip and horsepower, and that of cost!

Ron Tauranac and I worked on a low-cost club racer design a couple of years ago, and we based the safety requirements on F3 - it was all sensible stuff, but the regs weren't conceived around the folded aluminium design that we had in mind.

Ron T designed a car in the early nineties for the Honda Racing School at Suzuka. It was an aluminium honeycomb car with a very novel construction method which would have allowed the cars to be shipped in "flat pack" form (Ikea syle) for assembly in Japan. The cars were eventually built in the UK and shipped to Suzuka ready to run. Honeycomb panels remain a very viable material for chassis construction - probably much cheaper to produce than the complex spaceframes currently seen in FF.

Wonderfully practical approach to building cars! Sounds somewhat similar to the way the Reynard-designed FVauxhall/Opels worked, with honeycomb "planks" forming most of the structure...

[doc knutsen]

[QUOTE]Originally posted by kayemod
[B]

This has been an interesting discussion, but a couple of points regarding doc's post. Maybe he doesn't remember the early days of carbon reinforcement, or maybe I'm just older, but it wasn't quite as he describes it, at least in the UK. The added carbon fibre was in the form of tows, which were like pre-cut lengths of thick black string with no twisting of filaments.

I have never seen tows of carbon here. What we used was a "strip" of carbon weave, about 100mm wide (referred to as "carbon tape" by many people at the time) which were available from Ciba-Geigy in the late Seventies. Many people used to add an X of the carbon tape across the major flat parts of a panel, added on top of the final layer of f/g in a wet lay-up. In itself, this did not contrubute to the stiffness of the structure (although such people as Mallocks did it this way on some C2 panels I purchased from them in the mid-Eighties) but it could be used to advantage
by being draped over a rib or a pattern of ribs made from foam and it gave a whole lot of extra stiffness for a small weight penalty.

They were incorporated as part of the moulding process, so they were indeed an integral part of the structure, they would have been pretty pointless otherwise. Also, if done right, they were very effective in stiffening thin moulded panels for hardly any weight gain. Doc mentions carbon weave, which may have been a slip on the keyboard, but around 1970, the stuff was virtually unobtainable in woven form, and in fact for several years afterwards, also for the most effective added stiffening you'd use unidirectional not woven material.

Again, my experience differs, although I did not experience working with carbon laminates until
around 1980. By the mid-Eighties, we used a lot of carbon/kevlar hybrid weave, which we still used it wet lay-ups with vinylester and later epoxy resins. We produced some excellent lightweight panels this way, without having access to an autoclave or a vacuum bag system.

The Coremat idea was sometimes used as a more economical method of strengthening thin mouldings, but usually as a later addition, not added in the original moulding process.

If we are still talking wet lay-up, that is not the way it was used here. We used it after the gel coat and the first layer of l/w f/g laminate, adding the coremat just when the fist layer of resin had got tacky, then added the final layer(s) of g/f and resin on top of the coremat while the panel was still inside the mould. The same technique was used quite successfully on carbon/epoxy laminates.


The two main problems with this stuff and similar materials are weight gain through resin absorbtion, and deformation of the outer layer caused by natural shrinkage of the resin, which is very difficult to avoid and almost impossible to disguise completely.

The resin absorption is a problem, but we did find ways to manage it to a reasonable extent. We had to do it this way, as there was no access to vacuum and autoclaves outside of the missile industry, and they were certainly not talking to a bunch of racing madmen at that time!