Aluminum frame vs Carbon

Because Ferrari's are raced in GT2/Alms/Grand Am where carbon tubs are not legal.

 

Basically yes.

 

The aluminum as used in the current chassis design is repairable, based upon nodes that are cast, capturing the extrusions...so after a 'mishap' you can fix it..

Ferrari of Houston has a Certified Shop with all the jigs...

As Mr. G knows, if you crack a carbon fiber component, it's basically "back to the oven" to make a new one.....analyzing the damage can be done, but it's not an exact science so they are rarely repaired, but instead replaced....

From what I understand......

Old Steel Frame Guy...

 

What about kevlar, has anybody thought of that?

 

Interesting....a great and concise answer.

 

Same deal as carbon fiber. The use of fibers, whether they be carbon or kevlar or fiberglass, in a composite material is the same. The fibers are embedded in a resin material, which gives it form and rigidity. The strength comes from the fibers. Whenever a composite is damaged, repair is difficult and expensive. When the composite is used structurally (as in a tub), it's "back to the oven" as BigTex says.

 

F40.

Was great until carbon came along.

 

Many of the cars use fiberglass for nose and tail. It's very easy to repair. One of the benefits. Guess how I know?

 

IMO, it's all about cost. A carbon tub would make the price of the car skyrocket. Carrera GT is about as cheap as it can get and still retain the other performance features. Production of composite parts is also relatively slow, and most manufacturers already have plenty of knowledge and equipment for working with metals.

 

this very question was put to the head of the 458 project because the new McLaren road car will use a carbonfibre tub.

His reply was that due to the numbers that the 458 will be built in compared to the McLaren, it made more sense to use an aluminium frame for financial reasons. He also mentioned that for a more "mass market" car it made more sense for everyday use.

 

I'm not sure how well carbon fiber holds up in terms of fatigue over many years of real world road use. Obviously can be made as strong as required in terms of absolute strength. Probably not a problem, but just a question I've had that I haven't investigated.

 

There was an interview in one of the car magazines over here (possibly Top Gear magazine).
I'll see if I can find it again in the shops.

 

I also understand the 456 hood was a composite of Kevlar and CF.

 

Only the 456M IIRC.

 

I know my hood is CF, just wondering on the Kevlar combined. FofSF mentioned the under side casting number referring to Kevlar. Still trying to google it all.

rik

 

There's nothing to do with racing in FIA GT/ALMS/ACO. There are cars with carbon tub there - their very own MC12 for instance. Mosler in lower class (GT3/4) and others. They still use steel roll cage to comply with FIA regulations. With steel space frame made to FIA spec one doesn’t need to get through FIA crash test homologation. So this reduces the cost of racing program considerably.
In terms of mechanical properties – aluminum extrusions and castings have considerably lower ultimate strength, fatigue strength and specific stiffness than those made of carbon fiber/epoxy composite. At the same time alu density i.e. mass is higher than density of carbon fiber laminate.
Alu still has its way in form of honeycomb used in sandwich panels core. As all know tubs are produced out of carbon/alu (sometimes nomex) honeycomb/carbon panels.
Kevlar has considerably different set of mech. properties so it is used in different applications than carbon. Mainly due to high resistance to abrasion and great ballistic strength, in race cars it is used in bottom outer layers (subject to frequent contact with track surface) and wheel wells. Also 8 layers of cevlar are obligatory in FIA F1 chassis constraction (side walls) - in order to help prevent penetration of tub by broken suspension bits etc. There where tubs produced from mixed carbon/kevlar fabric (most known is first Lotus F1 "cut&fold" chassis). In simple terms kevlar is not used for structural/stiffness oriented reasons but used in specific areas of chassis for its specific properties.
How ever, cost of producing chassis bonded/riveted/welded out of aluminum extrusions/castings is way lower when we talk about 360/430/458 production numbers.
Is it better from engineering point of view? No way.
Is it cheaper? Yes.
Think about why almost all suspension/chassis parts where interchangeable in F360 anf F430? (One can verify it easily by looking up F parts catalog) – one answer. Lower cost.

Thank You
Ted

 

It may seem easy to repair external body panels and brackets and such. We do a lot of wet lay-up vacuum bag repair and custom part fabrication with our restoration and racing services. Carbon is a little more difficult that S or E glass but definately not as hard to work with as Kevlar. You also need a large autoclave to do tubs and components made of pre-preg composites.

Repairing a tub is a whole different ball of wax and to repair one with extensive damage to original strength is not an easy task nor is it possible in many cases. Having the original mold and the big autoclave is paramount to repairing most which would mean sending back to the factory or simply getting a replacement tub.

Heat is also a big factor for durability and fatigue and that is why you see little temperature gauge stickers all over an F1 at high heat areas (brakes, engine bay areas, suspension and other components close to exhaust or other heat generators like again brakes). The epoxy resins are designed for the high heat but over time (and not much on an F1 car) they have to be replaced.

On what we call "vintage" race cars we see quite a bit of delamination of composite materials and components due to fatigue, heat and chemicals.

But in all fairness we see a lot of fatigue and cracking in aluminum stress members too as well as corrosion. We are already seeing quite a bit of corrosion on the 360 frames especially where electrical grounds interface and speed up the process with anode/cathode reactions.

 

Ferrari should have made the 458 in CF.
With the speeds this car is sure to obtain and considering the "typical" client that buys the car new, safety becomes a responsibility of the factory.
Step up Ferrari.

 

likely to do with the future IMO.

In a couple of years cars need to average x miles per gallon more than they do with their current cars...lower weight cars use less petrol.

That's my theory anyhow.

 

The MCC is not legal at Le Mans. Why?

 

Who told you the mclaren is going to be cheaper or even the same price? Its going to be a rarer car and once you look at the MSRP its more expensive than the 458, or the lp560-4.

Onto the subject, why the new Ferraris are still using aluminum instead of switching to carbon tubs, well first is expense, second is its difficulty to produce them in volume, as said before it takes time to properly manufacture carbon fibre tubs.

Then we come to maintainence and repair. Replacement is expensive, and producing enough to supply for all the potential demands are going to be difficult to keep up with.


Now regarding the carbon/alu composite used for tubs, I have a quick question if anyone knows what happened with pagani's research of the carbon/titanium composite tub? I was very interested to see what the result would be because I always thought other than titanium being an exotic and rare metal why not use that for the carbon composite. Anyone know what I'm talking about or am I crazy or something?

And I honestly dont see any safety issue from using an aluminum frame for a 200mph car. Look at the Jaguar xj220. It hit near enzo top speed using an aluminum frame.

 

There is also the financial investment Ferrari has in aluminum production/assembly facilities to consider.

 

Aluminum recycles.......