What is it about the GT40 monocoque chassis? - Page 2

Scott Calabro · 03-30-07, 08:43 PM

Fran,

OK.

OK.

NO, I'm up for a free / at cost demonstrator anyday !

Yes.

Yes.

I have no idea.

Cheers !

S

Jac Mac · 03-30-07, 09:31 PM

Quote:

Originally Posted by 5150

Fran

I have no idea.

Cheers !

S

Thats a worry!

Jac Mac

Scott Calabro · 03-30-07, 09:34 PM

No worries jac mac, I don't think you will be flying on any corporate jets anytime soon.

Russ Noble · 03-31-07, 01:47 AM

Quote:

Originally Posted by Joe T

Only point I would make on the monocoque chassis is if it is damaged beyond repair I believe it would take less time to completly replace than a space frame, no making up ally panels drilling and rivetting.

Joe,

Can't let you get away with that one!

I bet you could build and skin a space frame far quicker than you could build a mono chassis, particularly in the home workshop! However if you are talking about buying a mono and buying a space frame, I am sure you could buy an already skinned spaceframe and there wouldn't be much difference time wise. I'm betting a skinned spaceframe would be a helluva lot cheaper than most of the monos available too, with maybe the possible exception of Frans excellent offerings. IMHO

Cheers

Joe T · 03-31-07, 03:43 AM

Hi Russ

I will try to clarify my point, imagine a car that can have either a Mono or a Spaceframe chassis. Also imagine your paying for labour by the hour. In the UK that could be up to £80 an hour for a body shop.

Lets even make the Mono more expensive to manufacture, even though I am not specifically talkng about a GT40 and most car manufactures know there math but build Monocoque structures.

Now unless you are "Robocop" I cant imagine you could cut and rivet the ally stuff in and replace the chassis quicker than just replacing the chassis alone, so the time for panelleing up must be accounted for somewhere. If you DIY then fine, if its a commercial decision based on overall cost, not sure.

So paying for a damaged mono to be replaced I still dont think would be far off from replacing a damaged spaceframe.

On manufacturing costs, I actually build a spaceframe car , so far in the UK its not been a matter of cost its been finding someone able to subcontract this type of metal work too, figures have varied from £3000 to £5000 for each chassis, it is admit a bit complex with lots of triangulation but it seems to be getting harder to get this stuff done, the material cost is only £400.

Maybe I need a guy like you over here Russ........

but make sure you bring all your Robocop attachments also how much electricity do you use theres a bit of a green thing going on over here at the moment.

Russ Noble · 03-31-07, 06:51 AM

Hey Joe,

Don't worry about the green thing

when you get your gas guzzling GT40 on the road, the electricity issue will pale into insignificance

I think you are trying to compare buying a mono with getting someone to fabricate a one off spaceframe. If you were getting someone to build a one off mono, I don't think you could get that done for anywhere near your space frame cost of 5000 pounds! (sorry, no pounds key on my keyboard!)

But if you compared the cost from the manufacturers of say an ERA or CAV mono with say a Tornado or DRB skinned spaceframe, I tend to think (but don't really know) that the space frame would win hands down on cost.

Nevertheless I have to admit that an original mono is aesthetically very pleasing,

regardless of the obvious disadvantages of owning one.

Cheers

Fran Hall RCR · 03-31-07, 07:19 AM

can we talk about Audi transaxles too

...just having a little fun....

Scott Calabro · 03-31-07, 07:21 AM

I find this discussion most interesting, information is a GOOD thing !
S

Fran Hall RCR · 03-31-07, 07:22 AM

information is a good thing but its all been said on here many times in the past....hence my Audi trans reference.

edit....mono vs. spaceframe was my reference for the above comment

Russ Noble · 03-31-07, 07:33 AM

Well Fran, since you build both monos and spaceframes, and must obviously see both sides of the coin, maybe you could give us the benefit of your experience. Or maybe point to a thread where you have commented on this matter. As a man with a foot in both camps so to speak, I'm sure everyone would interested to hear what you have to say (or have said).

Cheers

Scott Calabro · 03-31-07, 07:38 AM

One would think that adding sheet aluminum skins to a space frame would not add significant strength. Like how several kit GT40 mfg's do it, UNLESS both sides of the space frame were to be covered with say .025 sheet and aircraft grade blind rivets were located about every 1/2" on center. Better yet fit and drill all the panels, then assemble wet with a structural epoxy.

S

Fran Hall RCR · 03-31-07, 07:57 AM

Love em all...each has its place .

There is no real price difference in manufacturing if you are properly set up to manufacture either.

A chop saw, Mitre gauge and welder and you can build a spaceframe in your home shop with patience and diligence.
The same can be said of a mono but shear, brake, punches etc etc are needed for a home built mono....so the costs to build at that level are higher...as is the length of time to fabricate.

This is also true in mass production....
We manufacture and assemble a mono every week at a very leisurely pace...as quality is important to us.
The cost to tool up and be able to do this was quite an investment...
The technology required not only in fabrication but also design is another area of great expense not often thought about, a good software package with design and machining capability is 30k usd plus......

In reality I am sure both chassis can be built for a very similar cost, when compared to the same finished level...ie; panelled and rivetted and ready for delivery, but in our case the mono much more quickly when designed for production......the key words here are designed for production.

I love chassis designs from Costins to McLarens and each has its place but one flavour will never satisfy everyone and as such we should buy em, build em and enjoy em.

Scott Calabro · 03-31-07, 08:05 AM

Very well said Fran !
Cheers,
S

Russ Noble · 03-31-07, 08:35 AM

Thanks Fran,

Right from the horses mouth

So there is no real difference, it all comes down to perception and personal preference. Horses for courses!

Keep up the good work,

Cheers

Fran Hall RCR · 03-31-07, 09:30 AM

There are many differences.....I have only written about the costs and time frame scenarios above.

The mono IS significantly stronger and obviously more correct ....but thats only my opinion , to each their own as we have said.

Scott Calabro · 03-31-07, 09:50 AM

Russ,

Did you build you're frame from a set of plans ?
Is it square or round tubing ?
If its steel, what alloy?

Best,
S

J. Salmon · 03-31-07, 10:41 AM

I have heard that carbon fiber tubs have a finite lifespan due to degredation of the supporting resin. I don't know if this is true or not, but I would assume repairing one after an accident is not for the home mechanic. But neither possibility detracts from the lust. And if you can afford the entry price (what 400k or so?) then I would guess the potential added costs are just a nuisance. I think it is fair to say this group of cars is really the top layer.

But full aluminum monocoques are still only seen on what most would consider true supercars (like the GT). Even with all things equal, there is an undenyable lust factor with an aluminum mono compaired to a steel spaceframe. Exclusivity, bragging rights, whatever, it is real.