cars

[lemur]

Are there any horizons for chassis-design or other technological innovations that will make it possible for passenger-vehicles to maintain their current size while losing weight but not strength? Are there certain plastics or designs that will make it possible to drastically reduce vehicle weight without losing volume and strength?

[SMF]

Lemur. I think that some of the carbon composites used in recent aircraft construction (stealth military and the 777) could be used for cars. The question is whether this method is practical for construction and, especially, for structural repairs often required for cars. SM

[lemur]

Lemur. I think that some of the carbon composites used in recent aircraft construction (stealth military and the 777) could be used for cars. The question is whether this method is practical for construction and, especially, for structural repairs often required for cars. SM

Idk, but what percentage reduction in the weight could they produce?

[CaptainPanic]

I would guess that if all the steel is replaced by composite materials, you can reduce the weight by 50%. Emphasis in the previous sentence on 'guess'.

[Realitycheck]

You've got a pretty big range. Carbon steel runs about .284 lbs/ci, while carbon composite can run down to .057 lbs/ci, but you would probably want your density at least closer to 50%.

Edited May 11, 2011 by Realitycheck

[InigoMontoya]

You could take a lot of weight out of car even with current materials.... Just start cutting back on features.

 

You DON'T need 200 HP.

 

You DON'T need an air conditioner.

 

You DON'T need cushy seats.

 

And on and on you could go. Strip a car down from what it currently is to a bare-bones tool to get you from point A to point B and... Well, what does a SmartCar weigh? That'd be a good baseline.

 

From there, sure, go for the carbon composites and such.

[CaptainPanic]

You could take a lot of weight out of car even with current materials.... Just start cutting back on features.

 

You DON'T need 200 HP.

 

You DON'T need an air conditioner.

 

You DON'T need cushy seats.

 

And on and on you could go. Strip a car down from what it currently is to a bare-bones tool to get you from point A to point B and... Well, what does a SmartCar weigh? That'd be a good baseline.

 

From there, sure, go for the carbon composites and such.

Define "need".

 

You do not need all those features to get from A to B cheaply and efficiently. But you do need them for a whole range of emotional reasons (impress yourself with going fast, impress others) and comfort. People drive a big car everyday because maybe they have to move something large one day.

 

Many people will argue that they "need" a big car for such reasons. (Please note that I agree with you actually - and I think that if people "want" it bad enough, they say they "need" it.)

Edited May 11, 2011 by CaptainPanic

[InigoMontoya]

Well, my bigger point was that a huge driver of weight is not old school materials, but rather the feature list of the cars. A very simple car need not weigh much at all (relatively speaking, of course). Put training wheels on a 250 cc motorcycle and now you're talking 500ish pounds for a 4-wheeled vehicle that can carry two people at highway speeds using cheap materials. Not the most practical, I realize, but that wasn't what the OP asked.

[lemur]

Well, my bigger point was that a huge driver of weight is not old school materials, but rather the feature list of the cars. A very simple car need not weigh much at all (relatively speaking, of course). Put training wheels on a 250 cc motorcycle and now you're talking 500ish pounds for a 4-wheeled vehicle that can carry two people at highway speeds using cheap materials. Not the most practical, I realize, but that wasn't what the OP asked.

I consider this a very relevant response to the OP. I often wonder why no one builds large, three-wheeled motorcycles like the ones used to haul passengers and cargo in Asia for use in the US and Europe. It seems to be a status-issue hindering adoption, but it's hard to believe that there are so few people willing to deal with sneering laughter from automotive snobs. As far as I know, these vehicles get excellent gas-mileage, can carry as much or more than a compact car, and can be partially or fully enclosed. I just don't know how much speed/acceleration/range they have - and as Inigo mentions they lack the accessories, including status.

 

 

 

[InigoMontoya]

Note: My location is California.

 

A number of years ago (maybe 6 or 8?) some motorcycle manufacturer made street versions of 4 wheel ATVs. Basically they took your run of the mill 4-wheeler, put street tires on them, added turn signals and such, and sold them as motorcycles. The CHP issued tickets for riding off-road vehicles on the highway and a court case ensued.

 

Basically the defense said....

 

1) The state treats these 4-wheeled vehicles as motorcycles for all licensing/regulatory purposes. Therefore they're motorcycles.

2) The state says that to be street legal, a motorcycle must have the following features....

3) The motorcycles in question have those features.

4) How are these not street-legal motorcycles?

 

And that was pretty much it. They won and the motorcycles were declared street legal. I saw exactly two of them in the weeks that followed (probably the same bike twice), but within a month the state legislature had simply drafted a law excluding 4-wheeled motorcycles from ever being street legal.

 

That doesn't address your question about the trikes, but I think it's relevant.

Edited May 13, 2011 by InigoMontoya

[lemur]

And that was pretty much it. They won and the motorcycles were declared street legal. I saw exactly two of them in the weeks that followed (probably the same bike twice), but within a month the state legislature had simply drafted a law excluding 4-wheeled motorcycles from ever being street legal.

And what was the problem with 4-wheeled motorcycles that was worth outlawing? Has anyone attempted to appeal the law in court?

[InigoMontoya]

And what was the problem with 4-wheeled motorcycles that was worth outlawing? Has anyone attempted to appeal the law in court?

No idea regarding what they didn't like... But I don't think there's a Constitutional right to 4-wheel street-legal motorcycles. As such, on what legal grounds would you challenge such a law?

Edited May 13, 2011 by InigoMontoya

[lemur]

No idea regarding what they didn't like... But I don't think there's a Constitutional right to 4-wheel street-legal motorcycles. As such, on what legal grounds would you challenge such a law?

idk, something having to do with reasonable definition of a motorcycle? I.e. you would think the plaintiff could show that there's no reasonable basis for distinguishing two motorcycles on the basis of how many wheels they have, and thereby repeal the law.

[InigoMontoya]

idk, something having to do with reasonable definition of a motorcycle? I.e. you would think the plaintiff could show that there's no reasonable basis for distinguishing two motorcycles on the basis of how many wheels they have, and thereby repeal the law.

Laws don't have to be reasonable unless they're infringing upon rights guaranteed or implied by the Constitution. Further, it is well-established that the states have the right to regulate what kind of vehicles are allowed in public roads. Reasonable or not, I don't think the case would do anything other than rack up some legal bills (but not too many 'cause I think the case would die pretty fast).

[lemur]

Laws don't have to be reasonable unless they're infringing upon rights guaranteed or implied by the Constitution. Further, it is well-established that the states have the right to regulate what kind of vehicles are allowed in public roads. Reasonable or not, I don't think the case would do anything other than rack up some legal bills (but not too many 'cause I think the case would die pretty fast).

Most constitutions seem to have some basis for arguing that unreasonable restrictions of liberty should be revoked. If someone wants to drive a 4-wheeled motorcycle and can show that she's being discriminated against unfairly relative to 2-wheeled motorcyclists, I'm sure there's a legal basis for defending her rights. Doesn't the constitution say something about life, liberty, and the pursuit of happiness? How does a 4-wheeled motorcycle pose a risk to anyone else's life or liberty more than a 2-wheeled one?

[Hal.]

I heard one of those stories from a time when Aluminium ( Aluminum ) was quite rare and somebody ( not a story with great references ) had a set of cutlery which was made of it . Supposedly , it was valued at more than it's own weight in Gold .Then someone went and invented a process to supply this new metal quite cheaply ( late 19th century , possibly ) and the value of this set of cutlery plummeted and the same set of cutlery was very cheap to make ( not a very happy housewife somewhere ) . On the one side , cheap , lightweight materials were available and on the other , somebodies investment in a previous technology had to make way .

 

Just another thought a little later ,

 

Does anybody really want a Mercedes Benz with a mass of 125 Kg ( superlight with imagination ) travelling down the road at 145 mph and the threat of a small crosswind being able to flip the car over ? I'd rather have a few tons of chunky metal holding me down .

Edited May 15, 2011 by Hal.

[CaptainPanic]

Does anybody really want a Mercedes Benz with a mass of 125 Kg ( superlight with imagination ) travelling down the road at 145 mph and the threat of a small crosswind being able to flip the car over ? I'd rather have a few tons of chunky metal holding me down.

I agree that a car can (theoretically) become too light... and that it would be a massive problem to keep it on the road. On the bright side, such light materials would finally make it possible to have flying cars! So, that's a good thing

 

But these days, even the lightest cars are often still half a ton (500 kg) at least... and they are often rather low (small profile exposed to any wind). We're quite far from the problem that you describe!

[lemur]

I agree that a car can (theoretically) become too light... and that it would be a massive problem to keep it on the road. On the bright side, such light materials would finally make it possible to have flying cars! So, that's a good thing

 

But these days, even the lightest cars are often still half a ton (500 kg) at least... and they are often rather low (small profile exposed to any wind). We're quite far from the problem that you describe!

Flying cars would be neat but dangerous when the sky gets filled with clunkers the way the roads are now. As for the issue of superlight cars traveling at super-high speed, can't lift be used to create downward force that would prevent cars from flipping at high-speed? That way, you could have very good fuel- efficiency at low-speed and high-stability at high speed, no?

[CaptainPanic]

Flying cars would be neat but dangerous when the sky gets filled with clunkers the way the roads are now.

True. But maybe people would learn fast, and the amount of accidents will drop quickly. I sure would want to give it a try anyway!

As for the issue of superlight cars traveling at super-high speed, can't lift be used to create downward force that would prevent cars from flipping at high-speed? That way, you could have very good fuel- efficiency at low-speed and high-stability at high speed, no?

Indeed, back on topic: sure, a good design could keep light weight cars on the road when they go at high speeds. But how will that help you in a gale force wind in a traffic jam (or when it's parked for that matter)?

[lemur]

True. But maybe people would learn fast, and the amount of accidents will drop quickly. I sure would want to give it a try anyway!

Was "drop quickly" a subconscious pun? Actually, with the new solar-powered plane that has been in the news I could imagine personal air-travel becoming more popular. If you can put a light-weight solar motor on a hang-glider or one of those go-karts on a parachute, why shouldn't people use such things for transportation? Generally, I think the biggest obstacle to adopting a wide-range of alternative vehicles besides cars is that people's time is so limited by traditional institutionalized work-scheduling. If the 40-hour week would be replaced with more flexible work-scheduling, people would have time to fly places at 20mph and/or walk, bicycle, or take a solar-powered car for that matter.

 

Indeed, back on topic: sure, a good design could keep light weight cars on the road when they go at high speeds. But how will that help you in a gale force wind in a traffic jam (or when it's parked for that matter)?

Gyroscopic stabilization and a skirt that keeps gusts from getting underneath the vehicle? Of course, if you're putting power into running a gyroscope, that sort of defeats the energy-efficiency of having a lighter vehicle, doesn't it?

Edited May 17, 2011 by lemur

[Hal.]

Does anyone see a mass production ' Kevlar ' and ' Carbon fibre ' industry around the corner ( this side of the end of the century ) ?

 

 

 

 

[CaptainPanic]

Does anyone see a mass production ' Kevlar ' and ' Carbon fibre ' industry around the corner ( this side of the end of the century ) ?

It's not a technical problem, I'm sure. Kevlar and other high quality polymer and composite materials are already produced in automated factories. It would just be a matter of making those bigger, and making more factories.

 

It's just a matter of the price. At the current price, the market is relatively small (although it's still industrial). And there is no real reason not to use good old fashioned steel or aluminium.

[lemur]

It's not a technical problem, I'm sure. Kevlar and other high quality polymer and composite materials are already produced in automated factories. It would just be a matter of making those bigger, and making more factories.

 

It's just a matter of the price. At the current price, the market is relatively small (although it's still industrial). And there is no real reason not to use good old fashioned steel or aluminium.

If energy scarcification continues, I would expect cities to increasingly densify. Big heavy steel cars are a hazard in dense cities with lots of pedestrian and other small traffic. The mentality that bigger=safer, e.g. SUVs, is a catch 22 as bigger also = harder to stop quickly, more damaging to smaller vehicles in collisions, require more lane and parking width, and of course less fuel efficiency. I don't think big heavy cars will go away because they have high-speed stability advantages, but I expect their use will be increasingly limited to highway traffic as urban traffic grows denser/busier with more smaller vehicles. This is just a logical consequence of energy scarcification over an extended period of time, no?

Edited May 18, 2011 by lemur

[Phi for All]

Collision detection equipment could obviate the need for more weight in a vehicle. That could be the start of an automated system though, and if we move towards that then we might as well embrace mass transit.

 

I always looked forward to flying cars (back in the 70's, we were told we'd have them by 2000), but I think we are still several decades away from consumer aviation at that level.

Most constitutions seem to have some basis for arguing that unreasonable restrictions of liberty should be revoked. If someone wants to drive a 4-wheeled motorcycle and can show that she's being discriminated against unfairly relative to 2-wheeled motorcyclists, I'm sure there's a legal basis for defending her rights. Doesn't the constitution say something about life, liberty, and the pursuit of happiness? How does a 4-wheeled motorcycle pose a risk to anyone else's life or liberty more than a 2-wheeled one?

Iirc, in California, a "motorcycle", having a narrow profile, is allowed to pass between cars when traffic is slowed. Upon checking, I see this is referred to as lane-splitting or white-lining. As long as it's done safely it's not a problem. If a wider 4-wheeled vehicle was classified as a "motorcycle", it seems to me that lane-splitting would be less safe.

[physics confusion]

Hi

I'm involved in something called the energy breakthrough here in Australia. Regarding weights, the team that i'm on has already produced a very fast three wheeler which weighs around 50 kilograms (you do the conversion) and are working on an even lighter one. The problem with anything with this sort of weight to size ratio as this is that the vehicles tend to work very poorly in corners (why roll bars are a nessesity) as once the air gets under them, they've rolled. The same problem is found in Le Mans cars. Simply put, the momentum of the vehicle causes instability when on this sort of weight to size ration.

 

With the flying cars, cars are NOT built to fly. In order to acheive this, the cars would literally have to become lighter than the Air around them.