All I could think of reading your post was....if a regular car could get 100 mpg.....what would a Prius get?

I would buy that car before I'd buy an Aptera

This is based on the same concept that RMI's Fiberforge Inc. has been showcasing for a few years. It's obviously a great idea. Liek Amory Lovins say's "Triple the efficiency of the car" through the use of this new carbon composite technology and tooling process. So a hybrid or plug-in Hybrid with it's weight cut in half could easily get into the 200+mpg range even with current battery technology.

I'm curious what would happen with an 8 MPH rear-end collision. How much of a carbon-fiber mess would be created? What would the repair costs be compared to a more conventional car of the same purchase price?

That said, it would be so cool to have a car made with a significant amount of carbon-fiber.

The only scientific way to figure this out would be to crash test the vehicle.

However, with contemporary engineering software, it is possible to simulate what would happen and engineer the car to achieve minimal damage. Doing so, however, might push the cost of the vehicle way up because you might have to use more expensive materials to achieve this.

There are many types of carbon fiber out there, and if one uses sandwich principles, the property of the finished sandwich will depend on the properties of the core material and, much more so, the properties of the core facings - the facings are the actual carbon fiber.

Their goal in this car seems to be to keep it low cost. Stiff carbon fiber costs quite a bit more than not so stiff carbon fiber. Its my guess that since they are aiming for "affordable," they will be using not so stiff carbon fiber. In general, the stiffer the fiber, the stiffer the resulting composite, but there are trade offs as "stiffer" might mean more brittle.

After passing that bit of wind :redface: we will have to wait until it hits the market to see their test data.

Virtually everything else in society has shifted from metal to plastic. Fifty years ago, everything was made of metal (and wood), but today, a LARGE percentage of items are now made of plastic. Carbon fiber may not be "plastic," but they are both organic materials (chemistry; carbon-based). I look at my father's old toys, radios, and car from the 1950s, and it's all made of metal. I look at what is available today and the same products are all made of plastic on the outside. Sit in the interior of a 1950s car and then sit in the interior of a new Toyota - it's all plastic! And that's not a bad thing. It's lightweight and costs less to transport around with you everywhere.

F8L, in light of your "200mpg" rough extrapolation ... I wonder if this means solar panels would be more viable. A solar panel is not going to power a car alone, but it's utility due to a lighter weight vehicle would improve.

It should if one assumes that solar panels continue to become more efficient as well. The same applies for any energy source like CNG and hydrogen. With less mass to move one could go much futher on a "fill-up", handle better, and be faster/quicker. A lightweight vehicle also reduces the amount of damage done during a collision as well assuming the majority of drivers are using such light vehicles. Panels will be designed to deflect impact and/or to crumple zones much like they do with race cars. Repairs could be made less expensive due to the reduced amount of bodywork required when refitting composite panels, especially if they panels come pre-impregnated with color.

I saw a TV special a few months back and a composite car developer was featured. That stuff is as tough as hell. They took a big fender and beat it all to crap with a giant sledgehammer. Don't know how it would do in a real wreck, but it was impressive.

The problem is gas has to get very expensive before the increased cost of the materials would become commercially viable.

It's great to see that carbon fiber can be made more durable. Earlier this year the Red Bull Formula 1 cars had a couple of minor "offs" hitting a few bumps on the grass and the cars literally broke into hundreds of pieces. A few years ago the FIA and Ferrari did some work using Kevlar with the carbon fiber to reduce the number of shards produced from even small accidents, but I don't recall anything coming from it. Granted, a Formula 1 car and a passenger car do have a few small differences with its design goals, but I was worried about the tendency of carbon fiber to shatter when hit.

Hmm, not even sure it was carbon fiber... it's been a while and my memory is rusty. I do remember it was a composite of some sort. My guess would be that the race car designers will sacrifice durability over weight to the extreme. I remember having a carbon fiber tennis racket in the late 1980s that was very tough. It would scratch but never shatter. And trust me, my tennis playing was bad enough that I slammed that thing down on the concrete in frustration quite often! My friends with metal rackets always bent theirs.

There was a spectacular crash in the tour de france the other day in which a rider smacked straight into a median road sign. All you saw from behind was him catapulting above the crowd and then the two halves of his carbon fiber bike following him. The sign was tipped back about 10 degrees! May not be relevant to a car body, but it was a dramatic example of what happens when you exceed the yield strength of carbon fiber.

The street legal Porsche Carrera GT uses a carbon fiber chassis, as do the street legal Ferrari F50 and Ferrari Enzo cars. If the NHTSA approved these cars public roads, then I'm sure Toyota could design something similar if they really wanted to. I'm guessing it's probably more expensive than metal frames though.

My guess is that they were not using the type of sandwich technology that I am talking about. One method of construction is simply to layer carbon fiber, and I am willing to bet that the shattered formula 1 race cars were using this type of construction. Some might call that sandwich technology, however, what I am speaking of is using say 8 layers of carbon fiber on either side of a light-weight core material such as aluminum honeycomb, or balsa wood. It is common to see this type of construction in things like snowboards. Believe it or not, this gives the overall structure more of an ability to resist bending and shear. Though I cannot say for sure, the formula 1 car sounds like it broke apart at least partly because it had little shear resistance. They may also have been using one of the stiffer carbon fibers, and it sounds like their design goal may just have been to have an aerodynamic skin.

Also, I think it is common practice to use a carbon body on formula 1 cars with all the parts attached to the body; the cars are designed to break apart in crashes. This allows more energy to dissipate in the parts falling off the car and, believe it or not, is a safety measure. If they did not make the parts so that they broke off the car, they might penetrate the body of the vehicle and, perhaps, seriously injure or kill the driver.

I'm dubious of such an increase in mileage just from reducing the weight. Lightweight cars like the Geo Metro or Smart Fortwo don't get anywhere near 100mpg. Drive train losses, braking, and wind resistance are big factors too.