Carbon FIbre Kit CAR!!
 

Hey everyone, I'm doing a project at the university regarding Lotus-7 style kit cars. I'm thinking of building a carbon fibre passenger tub, so essentially the front frame and the back frame will remain as they are (either steel or aluminum). From my initial calculations a carbon fibre tub would further reduce the weight (by at least 40kg):icon_exclaim::icon_exclaim:, and additionally enhance stiffness by about 20% :badgrin:. What are your thoughts? is there a potential market for it? what are the important considerations to take into account? Here is a picture of a similar prototype!

http://s200.photobucket.com/user/Sam...5_Pro.jpg.html

http://s200.photobucket.com/user/Sam...5_Pro.jpg.html

Cheers guys!

7Fan7 – Welcome to the forum. :cool:

Unfortunately, I don’t know much about the 7 replica market.

But I guess the market for a carbon fibre tub will be linked to the price.

I think the other thing to consider would be proving the strength of the joins between the tub and the front/rear frames.

Good luck, Paul. :)

Thanks a lot for the info Paul! Yeah I'd imagine price will be a dominant factor; however, I don't seem to find any manufacturers making use of carbon fibre chassis or tub, despite a few posts regarding Axon Automotive working with Westfield a couple of years ago and a project carried out at Cranfield uni. But thanks for the information.
I've talked to a few owners as well, and indeed the strength of the joints will be a key concern; so I'll definitely conduct further research on that.

Cheers,

7Fan7

You may want to read up some on this guy:
https://www.palatov.com

He was the first person to fit a V8 into an Ariel Atom and he and the guy who works in the shop next door (Tristan) have won some Pikes Peak titles in their time.

I have one of his cars, that Tristan did the major part of the assembly of. Great team and super hard working.

Check out all of his cars. One is a complete Carbon tub and frame.

You may also want to read up about the new Corvette. That might give you some ideas too.

I know you mention the 7, but perhaps using a new material may allow you to rethink the structure and layout.

Look how Ariel or rather Nick Smart, reimagined the Atom by taking a different look at the true user requirements and the materials at hand. That and a little lateral thinking (bringing in ideas from nature) resulted in something quite new and revolutionary.

What ever you decide, please keep us updated with your progress!

Edit: sorry, I'm not 100% sure they are still making the carbon version - you will have to check out the website!

From what I've read on the subject, carbon fibre isn't really an improvement on GRP for the kit-car market.

Although it's often described as 'stronger' than the equivalent weight of fibreglass or steel, what those who use the term mean is that it's more rigid than fibreglass or steel of the same thickness, so can be made lighter than either.

That sounds great, but it actually means that for a vehicle body or boat hull it isn't such a forgiving material as fibreglass, which will distort then return to its original shape under moderate impact forces, where carbon fibre would shatter. On a racing car the (minimal) weight saving might be worthwhile, but the increased complexity of production, cost and inherent fragility of carbon fibre would put me off using it for a home-built kit car project.

If you're set on using it then I'd consider coming up with an original design rather than yet another seven, and pitching it as a turn-key car at around the price of a Boxster or high-spec Elise for sale to those who like to brag about their unused weekend toy's technical specification after they've driven their seven series to the golf club.

Good luck whatever you decide to do.

Thanks a lot for that info! I'm having a look at their website and I have to say that his work is outstanding; I realise most of the chassis are made out of steel, while the body is carbon. Certainly gives extra weight-saving but with that much horsepower (5000 in the case D1PPS), whether the carbon body is really useful, besides bragging rights, I'm not quite sure it will make quite a difference.
You are right in saying that the Ariel has indeed taken true user requirements into consideration during the design phase. The seven-style cars would indeed benefit from a revamp or in fact redesign, since essentially the car hasn't developed much over the past 20years. However, a quick chat with the owners of such cars also reveal that many of them are content with the current design. It certainly has its flaws but, and I quote, they say "That's what makes the car unique and original".
I will definitely keep you updated on the findings!

Cheers for the information. That was very useful; in fact, you are right in saying that carbon fibre would be lighter than either steel or fibreglass of the same thickness. Additionally, carbon fibre would indeed shatter/sudden failure, but because it is so strong, it would only do so upon very high impact forces; thus, under moderate impact forces, whereas fibreglass would indeed go back to its original form (although I'm guessing that it will experience some form of plastic deformation depending on how moderate is moderate), carbon fibre would ideally be able to withstand such impact and be subject to elastic deformation; provided the force is not sustained.
I really appreciate your idea on developing my own design and in fact, I think will head into that direction rather than try to improve seven-style kit cars. I will keep you updated.

Cheers

Quick university survey
 

Hey guys, I really appreciate all of your responses. As part of the university project, I'm doing a follow up on owner's perspective of the carbon fibre tub. So I am currently doing a short survey (less than 5 min to answer), and I'd really appreciate if you guys could spare a couple of minutes to answer the survey. All responses will be stored anonymously and if you do have any questions, don't hesitate to ask. The link for the survey is below. And by the way, do not hesitate to distribute this link to other kit car owners that you may know of, whether friends, family, etc.

https://goo.gl/forms/kyjYgLPVGPcp3OaE3

Cheers guys,

7Fan7

One of the things said about fibreglass shells on top of a boxframe chassis used to be, "But what happens if you are hit from the side by a motorcycle?"

Admittedly, the chances are remote. Presumably a carbon fibre tub would alleviate the risk of death? Only a small angle, but could be valid.

Hi Barber,

Very good question, and response. I guess the chances are indeed remote, but yes the CF tub would certainly be safer than using a fibreglass shell. Of course, we also need to consider the impact. On another note, I'd appreciate if you could answer this very quick survey, which aims to assess your perception of the carbon fibre tub. Your responses will be stored anonymously! The link to the survey is:

https://goo.gl/forms/qC9vRV5eGaoh20G33

Cheers,

7Fan7