Clockwork Vehicle

[Rowan of Rin]

Now now Harold, before you say this has been dealt with, I would like to know if there is any possibility of making some sort of spring driven vehicle, or any person transporting size, using all the technology available to us. If a super stiff material is used, and it is wound with a high torque engine (such as a steam engine ), would it be possible to be able to get the power to get a person perhaps half a kilometre or more without running out of 'juice'? 
Now, this is merely an exercise of 'can', rather than ease, or energy efficiency, but I can imagine through imaginative gearing, you could get a steady flow of power to the wheels, and safety wise, if the spring is contained in a barrel, much like a clock mainspring, I fail to see where the danger lies.
Thoughts/designs, everyone?

[Narsil]

The problem is the sheer amount of energy required to run a car for any distance at all. Springs have fairly low energy density as a storage medium. There's also the problem that any spring is going to need a very low ration drive train. Most clockwork devices don't actually require much energy to run, something like a watch isn't really accelerating or decelerating and the spring really just tops up the energy lost to friction.

An alternative solution would be to use very high speed flywheels, which are quite an effective way of storing energy mechanically. The main limitation is the strength of materials used and the fact that they tend to cause a LOT of damage if they fail. 

[Rowan of Rin]

It may be the fact that I am very tired at the moment, but would you mind explaining how a flywheel can store a lot of energy? Is it just due to their momentum, or am I missing something fundamental here?

[Narsil]

It's plain old kinetic energy.

The kinetic energy of a flywheel is calculated as half the moment of inertia times the square of the angular velocity. To use the energy the flywheel can simply be connected to an output shaft.

They will be bringing a similar system in Formula One Racing next year to recover braking energy (some systems will be battery/generator based).

[HAC]

Regulation of power flow will be your biggest problem. In a watch you want torque, but a slow "unwind" rate. Remember those old clockwork toy cars where you pulled them backwards to wind a spring? Letting them go gave you all the power in a short burst.  Gearing and some sort of friction clutches may help here.

Cheers
Harold

[Sir Nikolas of Vendigroth]

Well....Well...what'd you make your spring out of? Unless the answer's Unobtainium, your best bet's steel.

And steel's interesting stuff, in that the stiffer you make your springs, the less springy you make them. The springiness of spring steel comes from a heat-treating process. The more you heat hardened steel, the softer it gets, and the more springy. Up to a point. A stiff spring'll have a relatively low brittle limit of force, meaning it'll break, rather than be rather springy. A softer spring'll have a brittle limit that's higher than the elastic limit, meaning that it'll bend rather than break, but lose its springiness. If you temper, and therefore soften the spring even further, you'll run up against the plastic limit, meaning the spring'll act like unhardened steel.

I'm afraid that from a metallurgical point of view, the answer's no.

[vt13013]

It's plain old kinetic energy.

The kinetic energy of a flywheel is calculated as half the moment of inertia times the square of the angular velocity. To use the energy the flywheel can simply be connected to an output shaft.

They will be bringing a similar system in Formula One Racing next year to recover braking energy (some systems will be battery/generator based).

Another interesting usage for flywheels, as a type of short term, uninterruptible power supply. I've included a link to a related article.
http://searchdatacenter.techtarget.com/news/article/0,289142,sid80_gci1288892,00.html

Cheers.

[Narsil]

I've also hear talk of using them as power supplies for satellites, not only would they provide energy storage but by having three or more mounted perpendicular to each other the satellite could be steered by the gyroscopic effect of moving energy from one to another .

[Mr. Boltneck]

Funny, a couple of us were discussing this here at work this morning.
A back-of-the-envelope calculation will soon tell you why nobody builds a clockwork flivver: the amount of energy to accelerate your vehicle, and then shove it through the atmosphere, is roughly the same for a given size and shape of vehicle, regardless of the source of motive power. So you would need to build a spring which stored something like the energy in a tank of petrol/diesel/alcohol/etc. in some fairly small space. Such stored energy at that kind of density in a device made of, say, heat-treated steel, is more or less a fragmentation bomb that just hasn't gone off yet, if it were even possible to make a spring that strong.
Everyday examples can be found if you read the safety warnings on heavy-weight springs of any type, particularly the coiled ones. Or the dangers of large wire ropes or heavy wire breaking under tension, which can include amputation if you are near the recoiling ends (more or less a linear spring).
Sorry, because I wouldn't mind having one myself.

[Prof. Brockworth]

*sniff* You mean the clockwork train in Syberia wasn't real?   

[Mechanism Man]

Ah, clockwork, so very 'last year'....  but gyroscopic propulsion, now thats where the future lies!  (...maybe...)

http://www.gyroscopes.org/propulsion.asp

[HAC]

Ah, clockwork, so very 'last year'....  but gyroscopic propulsion, now thats where the future lies!  (...maybe...)

http://www.gyroscopes.org/propulsion.asp

Progression by precession?    

Cheers
Harold

[fciron]

Perhaps we can power the gyroscopes with hyperactive gerbils. Everyone please send me your jellybeans for research purposes.

[Nattravn]

I dont know if you guys ever saw "Planet Mechanics" show on National Geographic? Those guys built a moped for delivering lunch sandwitches that was propelled by a can of compressed air. The moped had a range of about 4km and a top speed of about 25 km/h. Now... if you had a larger can from wich you filled your moped that in turn was filled by a waterweel or steam engine powered compressor. Would that be steamy enough for ya?

[Mr. Boltneck]

Indeed, there is a French company which is supposed to start building a short-range compressed-air vehicle.
One nice thing about compressed air is that it is almost safe, at least as compared to steam or enormous springs.
There is a car that someone in my part of the world built which has a large wind-up key sticking out of the top of the trunk (or boot, if you prefer). When the car moves, the key revolves. I think Make magazine did a write-up. I first saw it a couple of years back on Lawrence Expressway, and did a double-take, which is a notably unsafe thing to do in traffic.

[neon_suntan]

Gyroscopes....

Wasn't there a mad scientist [or con-man?] who claimed he'd found an unknown property of gyroscopes to make them into some kend of free-energy source?

I realise his claims like every other "free-energy" claims are undoubtedly rubbish...

[Mr. Boltneck]

Possibly not so much a mad scientist as a vexed professor of engineering. You are most likely thinking of Eric Roberts Laithwaite. Read about him at http://en.wikipedia.org/wiki/Eric_Roberts_Laithwaite. I turned up the name in an old Fortean Times.

[von Corax]

I can't give you a name, but I remember hearing about a chap who claimed to have a motor powered by tuning forks. He proudly showed off his machine shop which was powered by the thing (which I gather was about the size of a toaster-oven), steadily humming away with no apparent source of power; he was written up several times in early issues of Scientific American; he took lots of money from lots of investors and promised he'd have it to market Real Soon Now, but there was always something that needed to be fine-tuned first.

After his death, his creditors tore the house apart and discovered that the "motor" casing concealed a small, powerful turbine which was driven from a compressed-air tank hidden in the cellar.

Not clockwork, I realize, but that may have been what you were thinking of.