Carbon auto bodies

The 7E7 is going to be made mainly of carbon fiber/epoxy resin composite. The reason they will be able to do this is that manufacturing costs of the composite has come down enough so that it’s economically feasible.

So when is it going to be economically feasible to make car bodies out of them?

“Economically feasible” means benefits justify the cost. Reducing weight of an aircraft has significant benefits, but I’m not so sure about automobiles. A lightweight carbon-fiber car would allow you to use a smaller engine and result in better fuel economy, but consumers don’t seem to be interested in paying extra for lightweight cars. If light weight is that important, they would have switched to aluminum a long time ago.

Currently the motorcycle industry is making a number of parts from carbon fiber to reduce weight (and because it is stylish) .

For example my bike has a carbon fiber muffler.

Here is a source describing a program attempting to get carbon fiber costs down to the range of $0.20 to $1.20 per pound, at which point they would be likely candidates for large scale automotive use:
http://www.eere.energy.gov/vehiclesandfuels/pdfs/success/carbon_fiber.pdf

It seems that typical costs of fiber is now about $15 to $20 per pound and use would be widespread when costs start getting under $5 per pound.

Of course, equivalent steel parts are much heavier, but steel might only be $0.25 per pound.

I helped make the carbon-fibre shell for the UofA’s solar car entry a few years back; on that car, weight is of course a big issue. The savings on an already-gasoline engine car aren’t going to be near as good, plus I imagine steel has advantages in strength and tooling. I don’t think you’ll see it until engine sizes or fuels change.

Carbon fiber parts are already used on the Boeing 777, items such as floor beams, trailing edge flaps and structural supports. Other programs such as the 737 and 747 have adopted some CF parts too. I have been fortunate enough to work on both the 777 and 737 Next Generation from their production start ups. Now that the 7E7 is going to be built in Everett, I may get to help launch another new airplane.

The use of alternataive materials for automotive bodies is affected by not only the cost of the material itself but the cost of manufacturing the parts, assembly methods, repairs and replacements.

Fiberglass has been used on Corvettes. “Wrap your a… in fiberglass.”
Plastic for the Saturn is it?
Aluminum.
Stainless Steel for the DeLorian.
Steel still the best all-around body material for general use taking all the factors into account.

I’ll go out on a limb and predict that carbon fiber or kevlar will replace fiberglass first in Corvettes or some other high end auto.


“Bewar of the Cog”