Question about the aluminum frame

[nickolas]

I was watching photos of a naked R8's body structure and was (negatively) surprized by the aluminum skeleton structure.

In the R8 it is pretty much a variety of aluminum bars that are somehow "glued" together.
Contrary to that, in most other sports cars (all modern Ferraris for instance) the aluminum body panel is a single sculpted piece of metal. Basically 3 parts, front, rear and passenger compartment connected together.

The funny part is I don't think that having a monoblock design (hope I use the wright term) would cost significantly more.

Well is my impression about the Audi design (less rigitidy and more weight) wrong or is there another explanation?

[R8 England]

Not glued. Welded...............


For more complex structures, single pieces are simply not posssible and it is necessary to assemble from parts and weld.

Remember, it has to meet all the EU and US crash test standards.

The alarm engineers had mine apart to fit the alarm. The aluminium bars and sub-frame in the passenger compartment are SUBSTANTIAL.

On another thread are photos taken of the chassis at the Paris show in September last year.

I visited the show and was amazed at quite how much metal was in the frame.

Also, elsewhere on the site are pictures of a few (deceased) R8's that met their maker. All have the passenger compartment intact, and that's the important bit.

No worries with an aluminium frame.

[geffers]

we all know that the R8 platform is a fantastic achievement for rigidity, safety and stability but I do wish they'd focused more on the weight savings!

[mad-dot]

Here's a video of the R8 being built. Shows some welding of the chassis.
http://www.youtube.com/watch?v=6eIkO4Wlc4g

[bz888]

Hey Geffers, just FYI, the entire R8 Alum Space Frame weighs less than 200kg!! Which is amazing!! I even got to lift it at the Neckarsulm factory!

BUT, I do agree the car could weigh less! Maybe the the Quattro system, Luxury Items, Safety Devices etc have increased the weight. Perhaps they could use Carbon Fibre Prop Shafts for the drivetrain to save weight???

[geffers]

yep imagine the performance and handling benefits even if the car was just 10% lighter. I've tried to omit options that unnecessarily add weight e.g. powered seats but just couldnt help myself with some of the others like the B&O system.

A bit like Gordon Murray with the F1, if they were given the brief to go back and review everything for weight savings I reckon they could find 100 kg without breaking sweat. BMW and Porsche do this kind of thing with their CS versions.

[bosscobra]

NIC,
Whats your point? I'm just curious, do you know anything about structural engineering?

[nickolas]

Oh no far from it.

Here is a vid of the Carrera GT structure. The passenger cabin is an one piece design, the rear of the car another single piece and the front pretty much a couple of bars not connected together propably for collision energy absorption purposes.

http://www.youtube.com/watch?v=C_fbZVKnxec

I was simply expecting something similar from an Audi costing twice the M3 money.

On the other hand the R8's structure reminds me of british "do it yourself" kits of Caterham like cars and that is by no means a compliment.

[imclueless]

This is Carbon Fibre structure inherently stonger and lighter (and more expensive) than aluminium.

You are comparing apples and oranges

BTW R8 is 50% more than an M3 not 100% and the R8 is approx a quarter of the cost of a Carrera GT

[bz888]

Look, i'm no genius, but I don't think you can extrude ONE single piece of aluminium and make an Occupant Cell for a motor vehicle. HOWEVER, Carbon Fibre can be made into whatever shape you want! Eg, it's used in this example of a Safety Cell in the Carrera GT.

A Safety Cell can't be made in one single piece of Aluminium. Impossible IMO.

BTW: I think the word you are chasing is Monocoque (Which relates to Saftey Cells because they are 1-Piece Design) NOT Monoblock.