157mpg

Sxotty said:
Well there is something to be said for backing up an opinion with facts at some point instead of just rambling on...

Bigus carbon fiber is strong in compression as well, I am not sure where you get your info that it is not. Though it is true that the way it was woven in the past was often very detrimental to compressive strength, that is no longer the case.

Carbon fiber would be economically competitive if it was used on the right scale, but there are serious problems in the failure modes of carbon fiber and that in an accident you would end up with very sharp pieces of material skewering and killing people unless you did all kinds of stuff which would defeat the entire purpose of being light and strong. Also there would be no frame straightening on a vehicle after an accident, and I don't think recycling would work well. Buying used cars would become incredibly risky since it is hard to detect defects in composites as shown by the tail of that airplane falling off.
Do you know if they can actually make an entire car out of carbon fiber right now?
 
DiGuru said:
I'm currently working at a company with multiple factories where they make the dashboards for the European models of Ford. And I can say, that in the last three evolutions of those, the parts have gone from being build from many metal plates, screwed together, with a plastic covering, to composites consisting of only two separate parts, foamed together.

Goes for every manufacturer. Weight counts as always.
 
Sxotty said:
Well there is something to be said for backing up an opinion with facts at some point instead of just rambling on...

Bigus carbon fiber is strong in compression as well, I am not sure where you get your info that it is not. Though it is true that the way it was woven in the past was often very detrimental to compressive strength, that is no longer the case.

Carbon fiber would be economically competitive if it was used on the right scale, but there are serious problems in the failure modes of carbon fiber and that in an accident you would end up with very sharp pieces of material skewering and killing people unless you did all kinds of stuff which would defeat the entire purpose of being light and strong. Also there would be no frame straightening on a vehicle after an accident, and I don't think recycling would work well. Buying used cars would become incredibly risky since it is hard to detect defects in composites as shown by the tail of that airplane falling off.
But it is completely unneeded unless the people here are complete idiots, in which case you've done those poor souls a service :D
 
Sxotty said:
Bigus carbon fiber is strong in compression as well, I am not sure where you get your info that it is not. Though it is true that the way it was woven in the past was often very detrimental to compressive strength, that is no longer the case.
I get my information from experience, being several years of classified work on US military projects implementing composites in a variety of structural situations.

Compression strength is still only about half that of tension in the best of cases, depending on the geometry and load. In real world cases you often see compressive strength around a quarter of tensile strength. But compressive failure isn't always the problem either... in some bending situations where interlaminar tension creeps up too quickly due to geometry the failure load is just a couple of percent of the tensile load, at best. And interlaminar shear is always a problem, especially around joints, that has to be kept under control. Using a stitched cloth to remove crimp reductions only slightly improves compression performance... ultimately, you are still talking about very long very thin individual fibers that each microbuckle in an Euler fashion because the matrix doesn't have enough stiffness to prevent it.

Carbon fiber would be economically competitive if it was used on the right scale...
More economical, but "economically competitive" really depends on the application. I've worked on a project implementing carbon on a massive scale compared to what most people are accustomed to, and it is still outrageously expensive. Sometimes, when high performance is required, carbon can be competitive with other alternatives (e.g. when you need extremely light weight, high strength, and especially both). But in cases where good ol' steel, plastic, or even aluminum do the job just fine its hard to make carbon cost competitive. And its not just the material, either... pretty much all aspects of the manufacturing process are more expensive as well. Maybe if every automaker decided to stop producing steel cars and opted for carbon fiber instead, that scale of cloth production might bring the costs down to more competitive levels.

...but there are serious problems in the failure modes of carbon fiber and that in an accident you would end up with very sharp pieces of material skewering and killing people unless you did all kinds of stuff which would defeat the entire purpose of being light and strong.
Just add a layer of kevlar on each side of the laminate. A bitch to work with, but it does the job well.
 
nintenho said:
1. Yeah, but at least it's a more enlightened level of compensation.
2. I was wondering if you maybe knew more about how economically feasible it was. Is that really so naive?:rolleyes:
Sorry, guess I was a little too sensitive.

I don't think anyone has a good grip on nanotube structural application right now. I'd put it in a similar category with quantum-computers... some stuff has been demonstrated in the lab, some results are extremely impressive, and a lot of conceptual work has been done but there are large practical/physical pieces of the puzzle to be worked out before either are ready for real world use (with the caveat that I think nanotubes are a lot closer to commercialization than quantum computing, if that means anything).
 
nintenho said:
Do you know if they can actually make an entire car out of carbon fiber right now?
Depends on just what you mean by "entire." All body panels and chassis structure? Yes. Even the suspension has been made of carbon on formula and Indy cars. Certain other parts, like interior pieces and peripheral engine parts can be made from carbon fiber as well. Rims can be carbon too, if you really wanted to.

If you push it, you can even make some bushings and pins from carbon fiber, such as in some suspension pieces.

However, carbon isn't good for threading, machining, or welding, so you probably won't replace a lot of the mechanistic parts of a car with carbon (i.e., a lot of the suspension pieces, brakes, transmission, etc.). And since the matrix isn't that great for heat you won't see a mass produced carbon engine block in the near future... though I do think a carbon fiber/ceramic matrix has been tested in the lab for similar high temp applications. And of course carbon is a stiff material, so you wouldn't want to force it in places where pliability is good thing, like shock mounting, hoses, etc.

But for the most part, if you take a formula car to be a "car," then yeah... they've done about as much as they can out of carbon fiber.
 
Bigus Dickus said:
Depends on just what you mean by "entire." All body panels and chassis structure? Yes. Even the suspension has been made of carbon on formula and Indy cars. Certain other parts, like interior pieces and peripheral engine parts can be made from carbon fiber as well. Rims can be carbon too, if you really wanted to.

If you push it, you can even make some bushings and pins from carbon fiber, such as in some suspension pieces.

However, carbon isn't good for threading, machining, or welding, so you probably won't replace a lot of the mechanistic parts of a car with carbon (i.e., a lot of the suspension pieces, brakes, transmission, etc.). And since the matrix isn't that great for heat you won't see a mass produced carbon engine block in the near future... though I do think a carbon fiber/ceramic matrix has been tested in the lab for similar high temp applications. And of course carbon is a stiff material, so you wouldn't want to force it in places where pliability is good thing, like shock mounting, hoses, etc.

But for the most part, if you take a formula car to be a "car," then yeah... they've done about as much as they can out of carbon fiber.
Oopsy-daisy, I meant nano-tubes, not carbon fiber.
 
Oh, then that would be a resounding "no." So far as I know, carbon nano-tubes, while forming in fairly routine combustion processes that you could duplicate in your kitchen, haven't been manufactured in continuous fiber form in large enough quantities to do much of anything useful.
 
Bigus Dickus said:
Oh, then that would be a resounding "no." So far as I know, carbon nano-tubes, while forming in fairly routine combustion processes that you could duplicate in your kitchen, haven't been manufactured in continuous fiber form in large enough quantities to do much of anything useful.
Thank you kindly, your intellectual girth is truely humbling.:D
 
UPDATE:
http://www.ifenergy.com/50226711/loremo_on_the_edge.php
Seems they debut the car at the geneva auto show.

woot.
epic
 
"Standard features include airbags, particle filter, dashboard computer, and air conditioning."

I'd rather have no A/C, while it makes a bit more sense that home A/C, I still don't need it as it consumes energy and gets rotten (bacteria) if you don't use it or clean it. Is it even possible to get a new car without A/C?
yeah A/C is nice, but my car doesn't have it and my parent's cars never had it.

I'd like to see a gas version, diesel is nice but more suited to long trips (and already doesn't bring that much to a small light urban car). gas is as good for city and small rural trips when the car doesn't have the time to heat much. and engine is more light and simpler. Choice would be nice.
 
I still don't need it as it consumes energy and gets rotten (bacteria) if you don't use it or clean it. Is it even possible to get a new car without A/C?
yeah A/C is nice, but my car doesn't have it and my parent's cars never had it.
You might want to see a few more inches of the world. Live in a desert or in a humid sweltering cesspool or in tornado alley or hurricane central and then you'll see why A/C is an absolute must (if at least from the point of view of the manufacturer who will have to sell a given model in dozens of regions).

I'd like to see a gas version, diesel is nice but more suited to long trips (and already doesn't bring that much to a small light urban car). gas is as good for city and small rural trips when the car doesn't have the time to heat much. and engine is more light and simpler. Choice would be nice.
Gasoline-powered will never come within the same realm of efficiency as a diesel. Much as you might think the choice is a good thing, the gain in fuel consumption rate will cost many times more than the difference in cost of the engine. Especially in EU where diesel is typically cheaper than petrol. Moreover, the torque of gas engines in the low rpm range is an absolute joke compared to any comparable disel, though you can rev that much higher on gas. But of course, revving higher defeats the purpose entirely, as that equals more consumption.
 
Back
Top