Car Tech: What are the pros and cons of plastic cars?
- 6/6/07 1:57 PM
Nothing left after a car fire
by jwolffie - 6/20/07 8:35 PM In reply to: What are the pros and cons of plastic cars? by wcunning
Have you ever seen a Saturn, mostly plastic, after a engine fire? It starts at the front and burns all the way to the back. All that is left is the engine/transmission and some of the steel cage parts. Very impressive!
car fires
by batman823 - 6/21/07 6:00 AM In reply to: Nothing left after a car fire by jwolffieCars, regardless of the body, will burn all the way back. The cloth materials to make the carpet and seats will burn, as well as the person's clothes and fat. Disregard the gasoline that fuels the fire, there are polymer cushions in those seats too. The paint and the plastics emit toxic fumes, killing the driver and passengers. So your point really is moot.
Car fires
by Andy77e - 6/30/07 9:26 PM In reply to: car fires by batman823Not so. In a metal car, the firewall should, in many cases, prevent or at least delay an engine fire from spreading to the passenger compartment. Also, in older cars, the trunk was also isolated. No longer as most of the time back seats fold down revealing access to the trunk.
However when your door and quarter panels are made of plastics, the fire can jump around the firewall pretty easy. However, car fires are not nearly as prevalent and safety features all around, make a fire not really a large enough factor to deal with for this discussion.
Bottom line: a car fire isn't a big enough issue to use as a reason against plastic.
that was kinda my point
by batman823 - 7/2/07 5:08 AM In reply to: Car fires by Andy77eI know that the firewall is not just called that because it sounds cool, but you've seen gasoline on the ground in an accident. I'm sure you've at least seen a picture of an engine in somebody's lap. That means the firewall was destroyed by the force of the crash.
But maybe I should have said that to begin with.
If it's good enough for Boeing Jets....
by goldline1 - 6/20/07 8:38 PM In reply to: What are the pros and cons of plastic cars? by wcunning
The latest Boeing jetliners are being constructed of plastics – this material is lighter and stronger then aluminum thus yielding a more "green" aircraft.
Why not cars!?
whoa there!
by LMF5000 - 6/21/07 1:39 AM In reply to: If it's good enough for Boeing Jets.... by goldline1Boeing's 787 Dreamliner (the plane you refer to) is made of COMPOSITE MATERIALS (eg. carbon fiber or fiberglass) and aluminium, not plastics like you said.
My experience
by axslinger - 6/20/07 8:44 PM In reply to: What are the pros and cons of plastic cars? by wcunning
I am on my 3rd Saturn. In my second one (a SW2 Station Wagon), I hit a tree doing about 55MPH. I left the road doing about 70, took out a 4x4 mailbox post then hit the tree square on the passenger side. My front right wheel, with tie rods/suspension parts still attached, ended up about 30' away smack dab in the middle of the road I was just on.
The car was totaled. All I got were some scuff marks on the inside of my arms and a small burn on a thumb from the hot gas inside the air bag. Facts are facts and thats my experience.
Ax
Pros and cons of plastic cars?
by ncool - 6/20/07 8:48 PM In reply to: What are the pros and cons of plastic cars? by wcunning
If Bill Clinton can be First Lady and Rosie O'Donell can replace Bob Barker - who I am to think a plastic car is unrealistic?
Plastic in autos and other vehicles
by Rick Cavaretti - 6/20/07 8:56 PM In reply to: What are the pros and cons of plastic cars? by wcunning
Worried about plastics and other composites in your vehicles? Well, think about it this way: Most modern, if not all, jet fighters are made mostly of composites. These are vehicles designed to take 9-G turns and survive getting shot at with 50-caliber projectiles. Can your steel-only construction car take that abuse?
what about the cost...
by LMF5000 - 6/21/07 1:41 AM In reply to: Plastic in autos and other vehicles by Rick Cavarettican our average Joe afford to have a car made of such high-tech composite materials with such incredible strength? Don't think so...
yes
by batman823 - 6/21/07 6:10 AM In reply to: what about the cost... by LMF5000Yes, the average joe can afford composites. Composite materials and alloys are easily and plentifully produced. The ultra-high quality composites used in airplanes and fighter jets are a very minor factor when speaking of costs. I just going to go out on a limb and assume it's the billions of dollars in research, jet engines, missiles and other fighting technology that make those planes expensive.
The average joe can afford to buy a motorcycle or small car, at least take a loan out on one. The composites wouldn't make that big of a difference in the cost of a vehicle.
A composite is heavier than plasic but lighter than tin. It is also stronger by unit weight than steel. So there's really no downfall to using composites. Plastics would be cheaper and lighter while providing the same protection of zero that today's tin siding.
I'd buy that...
by Andy77e - 6/30/07 9:33 PM In reply to: yes by batman823Somehow I doubt this. I have no information either way (yet) but, it would seem to be a win-win for the car companies. Which of course makes me skeptical... "if it's too good to be true..." And since they haven't made a car from composites yet "it likely isn't".
automakers follow airlines
by batman823 - 7/2/07 6:00 AM In reply to: I'd buy that... by Andy77eWe've discussed the general history of things before. BMW made engines for airplanes for many years. But they started using them in their cars. The rotary enginges used in airplaines for decades are now being used in some Mazdas. They are very good engines. We'll see if they expand further into the market, and I'm not sure of the maintenance costs.
I read quite a few of the studies concerning composites vs metal, cost being a factor. I saw that in the late 70's to early 80's, the DOD started doing research on how to use composite materials in various things ranging from portable Army bunkers, to complete construction in Naval ships. Even in the 80's reports, during R&D phase, stated that the cost of composites were 3.3x that of the aluminum counterparts but the costs are "greatly overestimated... production is allowing for rapid reduction in cost of composite materials."(some army cost report)
Composites are also currently being used in aerospace testing and to put small satellites in orbit. They use composites because the roughly 10% increase in constuction cost today greatly reduces the weight and allows for better resistance to heat and stress. So for a car, give up the $2000 convenience package for composite-infused alloys and you don't pay any more for the car but you save more in fuel without sacrificing safety or strength.
All of the more current reports stated that composites on a mass-production basis could be equal or slightly higher in cost when compared to metal or plastic, but provide many benefits like strength and protection against catastrophic material failure.
Here's a link to the space one
http://www.ce.utexas.edu/em2000/papers/EFosness.pdf
You would think it'd be a win-win. Maybe it is, and it's just a matter of time. I'm leaning toward that angle. But we will know if/when composites are more widely used in cars.
One minor error.
by Andy77e - 7/2/07 9:51 AM In reply to: automakers follow airlines by batman823Some interesting information there. The link is informative as well.
The one error is with the rotary engine. This is an honest mistake because there's actually two engines that are both call "rotary" engines. But they are have absolutely nothing in common.
The Rotary Aircraft engine is seen here:
http://en.wikipedia.org/wiki/Rotary_engine
This engine is similar to a normal car engine, in that, it uses pistons and valves. However the crank shaft does not move. The cylinders with the pistons in them, basically the whole engine block, actually rotates around the stationary crank shaft. The propeller is fixed to the engine block, and as such, spins with it.
It is called a "rotary engine" because the whole engine rotates.
The Rotary Automobile engine is seen here:
http://en.wikipedia.org/wiki/Wankel_engine
or here:
http://auto.howstuffworks.com/rotary-engine.htm
This engine has no pistons, and no valves. It has a three sided rotor that spins inside an oval shaped housing. Each side of the rotor, acts like a cylinder, each doing a different part of the 4 part combustion process at the same time. (the four parts being "intake", "compression", "ignition" and "exhaust") For this reason, one rotor does the job of three pistons, which is why a 2 rotor rotary engine puts out as much power as a V6, while being only 1.3 liters.
Of course this is a called a "rotary engine" because it uses rotors.
These two engines have absolutely nothing in common. The car rotary was never used in aircraft. Supposedly the aircraft rotary was used at some point in a car, but I have never seen, nor found record of such. Anyway, good stuff.
Side note
by Andy77e - 7/2/07 10:28 AM In reply to: One minor error. by Andy77eIt appears Mazda was able to convert their "rotary" engine over to hydrogen burn cycle. Surprising since the burn characteristic would seem to indicate this would be difficult. I can only guess hydrogen does well with turbo charging.
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