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I think there are a number of factors that come into this, but cost to produce would probably rank highly on the list.
Plastic is made from Oil, Oil is notoriouly expensive at the moment (hence the fuel prices) - so the production costs would be quite high.
It also isn't as strong as other materials. The majority of cars have bumpers made out of plastic leaving just the main body, boot and bonnet out of metal. The lightest yet strongest of materials is Carbon Fibre, which is what the sports cars of today utilise.
There has been plastic used in the past, but that was really before Carbon Fibre became affordable, and it was still in the Sports Car industry.
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Shopping bags are made from oil, but they still give them away.
'Plastic' is generally cheaper than 'metal'. Metals use oil indirectly due to the high temperatures required for smelting and working.
polymers can be strong. Glock make their pistol frames entirely from polymer and those guns outdo all their metal rivals in durability tests. The problem with plastic is not very rigid in thin sheet form-unless you make it brittle.
Carbon fibre is too expensive and brittle to be a suitable mass market body material. It does score highly on the novelty measure though!
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Yep which is why the more upmarket sports cars have them.
I also get the feeling you shop at Asda too ... last time I went to Tesco they practically stoned me to death for asking for a Carrier Bag. :(
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Yep which is why the more upmarket sports cars have them.
Like Renaults
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Nowt wrong with Asda. Great fruit and veg and bread. And they chuck in a plastic bag free. :)
I think carbon fibre is often more of a sales gimmick to 'justify' a high sticker price. Remember, the motoring press raving about how aluminium engines were such a great improvement over 'pig iron'? Except for the lack of high temperature strength, porosity problems in the castings, lack of resistence to chemical attack, high thermal expansion coefficient, softness, lack of rigidity....
Serious engines stayed loyal to cast iron. Now the motoring press are drooling over Compact Graphite cast iron as the new wonder material!
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Carbon fibre also tends to be more labour intensive to produce and finish, hence more expensive. Its certainly not brittle. You can make it as hard or soft as you like just by altering the lay up and the resin.
Like all engines built to a price, aluminium engines are fine if designed correctly. The technology has been out there for decades. Just look at an F1 engine, its a piece of artwork. No problems with porosity, thermal expansion, softness or stiffness if designed correctly. Yes, they would cost more built to that standard, but it is affordable.I have ported many a block and they are incredibly hard to work. Cast iron is for tractors and ships!.
Edited by turbo11 on 28/07/2011 at 15:55
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Cast iron is for tractors and ships
And most automotive diesel engines? When you hit the high cylinder pressures, you reach for iron.Way more efficient than revving to make power.
How on earth can Aluminium alloys be hard to work? A grinder can mincemeat out of an aloy head , but be agonisingly slow on a cast iron head.
F1 engines aren't exactly known for their longevity. A big Scania or Cummins diesel will push 20 bar BMEP all day, every day which is far more impressive than a screaming diva of an F1 engine that needs to have it's milk warmed before it will start and has a TBO of maybe 3 hours. ;)
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CLIO's years ago had plastic front wings, back in the 1990s. I remember it being a sales thing at the birmingham car show, with sales reps flexing the wings in and out saying how good they'd be in a low speed crash....hmmmm
citroen BX had plastic bootlid and lots of other panels,
chap here has a 60 reg, civic also has a plastic boot. etc
gone are the days of steel bumpers, steel front valence...metal exhaust manifold!!!
guess its a....save weight, improve mpg/ performance thing.
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Diesel- fuel of the elzibub and yes certain aluminium alloys as per F1 blocks are extremely hard to work. i spent many hours,days even weeks machining and fetlling blocks, heads and gearbox casings and they are hard work. you obviously have never worked on them. Screaming F1 engines are music to the ears. Try building one, then stand next to it in the dyno when its doing a Hockenheim qualifying lap doing 19000 rpm. Makes the hairs on the back of your neck stand on end ( and your ears bleed!)Cummins diesels. Yawn tractors and ships..........
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F1 engines just sound like a bundle of rc engines stuck together which is apt, because like rc engines, F1 engines are toys.
They don't do anything particularly well and their design came about through badly written rules. A 2.4 turbo V6 running 9-10,000 RPM would be way more efficient than the N/A V8 running 19,000. Wider power band, longer TBO etc. This would make it more relevant to road use-which would make it more exciting.
That's why a cummins is exciting. It is very good at what it does.
Accoustic Quality? A top fueller idling beats the Black and Decker buzz of F1 2.4 hands down! Probably no further removed from road cars than F1...
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as usual lots of opinion and no experience. Top fueller- I've heard a few. All noise and not very good round corners.May as well sit on a giant rocket., but when you have built the thing yourself there is no comparison. Cummins exciting- get a life
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Serious engines stayed loyal to cast iron. Now the motoring press are drooling over Compact Graphite cast iron as the new wonder material!
105E crankshaft-1959>---But it didn't work with BP Visco-static.
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Yes aluminium is so bad an engineering material that Toyota and MB use it for diesel engines and Audi use it for car bodies...
And I remember a Rover V8...
Some recanting of serious carp is in order..
Edited by madf on 28/07/2011 at 17:04
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Sorry, you mean the Buick 215? A cast off from the GM division. It really wasn't a very good engine, was it?
VAG, BMW, PSA, Cummins, Detroit, Caterpillar etc all have class leading engines. All use cast iron.
Aluminium is a cheap skate's material. It's cheap to cast, weld and machine and that's about as far as its merits go. The heat conductivity is a double edged sword and on balance, I don't consider it to be a positive in engine materials.
Funny you should bring up the MB diesels. The high output ones use cast iron liners and steel conrods. Aluminium just isn't up to the job.
And from someone who thinks that a 350cc cylinder with an 18:1 compression is a good idea!
Buy a bike at Halfords for £50. What's the frame made from? Aluminium.
Buy an expensive bike from a cycle specialist. What's the frame made from? Probably high quality carbon steel. The thin steel tubes don't weigh any more than the bulbous machine welded girders that the aluinium bike uses. But you don't have to employ a skilled welder-so it saves money.
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"Buy a bike at Halfords for £50. What's the frame made from? Aluminium."
Buy a Sott G-Zero as used by their professional promo team (I have £3000 worth sitting in my garage) Lo and behold- its an aluminium frame.
At least its not cast iron :)
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I've a Claud Butler 2011 Chinook. It has a very light, tough precipitation hardening aluminium alloy frame.
My cast iron bike is going on Freecycle ;-)
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In my nukie days, precipitation hardening was what we spent our lives worrying about!
Didn't know you liked road cycling, Bobbin.
P.S. A road bike without drops looks so wrong!
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P.S. A road bike without drops looks so wrong!
Can't have drop handlebars; they make me lean too far forward and I've a dodgy back. It doesn't look wrong!!
I think there's a slight misconception about 'carbon fibre' here; carbon fibre reinforced polymer is what is used for vehicles. Popular for motorbikes as it has a very high strength to mass ratio, so you can make light, quick bikes. You can also build a very strong monocoque body out of it. If you think of it in the same way as cloth, or a basket, you can weave directionality into it, so it'll be strongest in the direction of greatest applied force.
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Can't drink beer, or wine. Dodgy back, You weren't manufacturered by Alfa Romeo were you?!
psst. I don't use the drops that much-no one does! But I couldn't get rid ofthem, or the downrube friction levers.
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Can't drink beer, or wine. Dodgy back, You weren't manufacturered by Alfa Romeo were you?!
You are so cheeky. Well at least that would make me good looking :-P
Don't say anything about 'well upholstered'...!
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Well most of the men here love you so the Alfa analogy holds.
[neatly recovered-Ed]
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Well most of the men here love you so the Alfa analogy holds.
[neatly recovered-Ed]
Neatly recovered eh? ;-)
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In my nukie days, precipitation hardening was what we spent our lives worrying about!
Didn't know you liked road cycling, Bobbin.
P.S. A road bike without drops looks so wrong!
In your nukie days where did you work. Were you ever at Harwell.
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No-but geographically close. I was at Oxford. Is Harwell that still running? I thought they shut the test reactor.
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There are 3 reactors still going on the Harwell site. They shut the GLEEP down about 5 years ago if I remember rightly.They're looking at 2020 shutdown and closure though. I was down there in the spring for NDA/RWMD work.
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*red mist of dread and dispair descends*
Bicycles.
Grrr.
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Oh! We couldn't get our test samples irradiated there (or so I was told!). Perhaps the bean counters were telling porkies.
Although I had the misfortune of reading some of the reports that emanated from Harwell. Pretty turgid stuff. Very necessary but utterly, utterly dull.
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I appreciate the view of a young lass in a vee-neck t-shirt reaching for the brakes on a drop-handlebar bike.
But I'm just an old perv.
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Its views like that which cause traffic accidents!!
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Its views like that which cause traffic accidents!!
I shall make sure I am zipped up to the neck just in case of accidents then; there's no need for any 'Hello boys' moments!
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There are 3 reactors still going on the Harwell site. They shut the GLEEP down about 5 years ago if I remember rightly.They're looking at 2020 shutdown and closure though. I was down there in the spring for NDA/RWMD work.
Yes, Gleep has completely gone. It was built from 10" graphite blocks. it had very low radiation levels and was used mainly for instrument calibration. Bepo should go next, and once all the residual radiation has gone then they will all be dismantled. I think 2020 is a bit optimistic.
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No-but geographically close. I was at Oxford. Is Harwell that still running? I thought they shut the test reactor.
I only ask, because since I left the automotive industry a couple of years ago, I now work on the Harwell campus. Thought I might know some of your former colleagues.
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I've wondered the same thing - pigmented plastic won't show scratches, is more resistant to minor dings and weighs considerably less. My BMW has plastic front wings, but they're painted.
Nowadays, cars have crumple zones and safety cells for crash management - the body panels are only there to stop the occupants getting wet when it rains. I suspect the real issue is retooling the factories to handle plastic panels instead of metal ones - small niche manufacturers don't have the same problem (hence the use of carbon fibre) because they already have the necessary equipment.
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Yep which is why the more upmarket sports cars have them.
Er, you mean the Pontiac Fiero??
<Drum sting>
<Cymbal>
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