h a l f b a k e r yYou could have thought of that.
add, search, annotate, link, view, overview, recent, by name, best, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
|
|
|
Please log in.
Before you can vote, you need to register.
Please log in or create an account.
|
Cars can be a LOT lighter than they are. Carbon Fibre panels, aluminium honeycomb structures, smaller size, better design... the mass of a 4 seater can be brought down to just a couple of hundred kilograms.
Add a drive system that employs a large flywheel in a magnetic bearing (very low friction)
that you power up by either using expensive electricity or the output of your turn on the exercise bike. You ride hard for an hour and you pedal less on your way to work the next morning. Passive energy recovery and some pedalpower would be good enough for most stop-start commuting.
Fitter population, cleaner air, less dependence upon private vehicles. Use the oil to build the vehicles, not power them.
Inflatable car
http://www.physorg..../news131804347.html
Light, even w/ electric engines [Bcrosby, Sep 08 2008]
Don't want a flywheel in your car? Go by bus.
http://www.accessto...rchive/s76a4325.htm
1.5 tons at 10000rpm! [coprocephalous, Sep 09 2008]
[link]
|
| |
To kickstart it in the morning, just run it backwards down the driveway on a cable, like a giant salad spinner. Gets it rolling and away you go. |
|
| |
you must have a really long steep driveway
(bub). Better have a system for towing it
back up. Sounds like the real idea here is
for a flywheel bicycle. But isn't this really a
flavor of flywheel power. I could propose a
flywheel cell phone or a flywheel drill. I
think the real problem here is that there
isn't a safe and user friendly way to
harness flywheel power yet. Somewhere
between a new flavor and scigic. |
|
| |
So, given a vehicle mass of 200kg and a
passenger mass of say 150kg, and given
reasonable efficiencies for energy storage
and recovery, with regeneration, how
massive a flywheel, of what diameter, and
spinning at what speed, would you need
to see you through a typical day? |
|
| |
Pretty frigging big, [MB]. |
|
| |
That's the answer I was hoping for. Go for
it. |
|
| |
If you're using pedal power to propel a vehicle, why not eliminate the flywheel and just have a bicycle? Use your hour of pedalling not only to get you fit, but to get you to work. |
|
| |
Shock, horror! you live too far from work to cycle there. But then, think about it, you don't have time to sit on an exercise bike feeding the same energy into a flywheel. |
|
| |
Note that modern batteries are far better for storing energy than flywheels. They are light enough for the job and much safer. Battery assisted bicycles exist and are good. You can even charge them up by clamping them to a stand, sitting on them and pedalling. |
|
| |
Note also that compared with physical exertion, power is very cheap. If you use a vehicle of similar weight and speed as a normal bicycle, such as the battery assisted bicycle I mentioned earlier, your fuel costs are very low. On the other hand, any kind of car sized vehicle will not go very far or very fast under human power. |
|
| |
There are some inflatable cars with batteries. |
|
| |
Once a car is about the same weight as a person, stop-and-go traffic is a cinch: you're already annoyed so pedaling away at a big gearing system makes sense. |
|
| |
What about driving 50 miles at around 60mph (ok, 55 mph when gas is more than $3.80)? |
|
| |
I wasn't suggesting I had found a way to make your ridiculously cheap (by international standards) gasoline any cheaper, so we won't go down that path. |
|
| |
I was trying to justify the use of a honkin' great flywheel and the smooth, suppressed sense of massive power that lurks within them, in a car you use every day. Makes your hair stand on end, to feel a big flywheel near you just cruising along at a few thousand revs. |
|
| |
The other use of the flywheel is to allow the flywheel to assist with climbing hills (The least endearing thing about pedal power). |
|
| |
I'm not sure a car with a massive flywheel in it would corner very smoothly... |
|
| |
[hippo] is right: the large spinning mass of a flywheel is a giant gyroscope, so rotating it in any direction but around its axis is not a good idea. That's also why it's harder to fall off a bike when you go faster: you're sitting on two gyros called wheels. Also, as [WcW] noticed, a spinning mass isn't exactly safe. I wouldn't want to be anywhere near the thing when it pops and releases 50 kW of energy in a fraction of a second. |
|
| |
The best place for a flywheel is underground. Since it's stationary then you don't expend energy to tow it around, and the ground will catch the energy (and shrapnel) when something goes wrong. Use an underground flywheel to store your house's energy, buy more at night when it's cheap and sell it when it's expensive. Use it as a backup instead of batteries or gennies. But that's a diiferent idea. Has it shown up at the Bakery yet? |
|
| |
I wondered about this one myself. Do you think that counter rotating flywheels would help minimize precession? |
|
| |
Probably turn it into a giant spinning top, with passengers inside. |
|
| |
but then they must be geared together and it's intuitive that gearing and all other forms of I/O are the death of flywheel efficiency. Either they are large or heavy and slow and thus not efficient for transportation or they are fast and dangerous and feed energy sapping transmission systems either way a no-go. I'm pretty sure that twin masses counter rotating parallel will still resist perpendicular motion thus not defeat the gyroscopic effect (but i might be wrong). |
|
| |
There are really good flywheels already they are used for emergency power in hospitals for sure. I'm sure they are used in other industries as well. They are made of spun graphite if there is a failure it turns into a fluffy ball and it doesn't get out of the vacuum chamber it is spinning in. Also counter rotating flywheels cancel out but i think in a vehicle the gyroscopic forces could be used for traction and cornering. |
|
| |