Shipping

If polywell fusion is developed, in what ways will the world change for better or worse? Discuss.

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MSimon
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Postby MSimon » Thu Jan 31, 2008 10:45 pm

Hunter Thompson was always one of my favorites.

He once sent me an e-mail saying he liked my writing.

Of course he could have been ironic.
Engineering is the art of making what you want from what you can get at a profit.

Roger
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Postby Roger » Thu Jan 31, 2008 10:49 pm

Dont forget 15 B-25's launched from carriers in the spring of '42.

The idea of shipping cars strikes as very funny, quite an inefficient thing.... no ? Is it better to have a factory that builds the cars roughly where the cars are to be sold...... ?

I'm just saying.....

bombast wrote: Put a half-gigawat reactor on board and you wouldn't have to make those trades.
Use railtransport and save the investment and be far more efficient to boot.
I like the p-B11 resonance peak at 50 KV acceleration. In2 years we'll know.

bombast
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Postby bombast » Fri Feb 01, 2008 12:11 am

Once the marginal cost of power is effectively zero, efficiency is meaningless. Do we really care if it takes 1 kg of B-11 to ship a million kg half way around the world, or 1/2 a kg? Cost is all amortized capital costs, which moves us in favor of fast transport and more transport cycles per year's worth of interest payments.

It makes more sense to build all the cars in one place (take advantage of economies of scale) and use the free power to ship the materials there, and ship the cars to their users.
"The music business is a cruel and shallow money trench. A long plastic hallway where pimps and thieves run free and good men die like dogs. There is also a negative side."
-Hunter S. Thompson

Roger
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Postby Roger » Fri Feb 01, 2008 12:55 am

bombast wrote:Once the marginal cost of power is effectively zero, efficiency is meaningless.


Thats the divergent point.
I like the p-B11 resonance peak at 50 KV acceleration. In2 years we'll know.

bombast
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Postby bombast » Fri Feb 01, 2008 7:40 pm

Roger wrote:
bombast wrote:Once the marginal cost of power is effectively zero, efficiency is meaningless.


Thats the divergent point.


Wow, that's powerful. I'm divergent. Here I thought I was just a geek. Sorry, I'll shut up and go away.

25 years ago Nicholas Negroponte at MIT's media lab asked a conference "what do you do with infinite bandwidth at zero cost."

We haven't quite gotten there yet, but things are going in that direction. We can reasonably extrapolate that our children will have effectively infinite bandwidth, data storage, computation and power at effectively zero cost. They will also have great freedom in designing purposed biological organisms.

Anticarrot asks why would anyone want to build a ship that goes fast. If you don't have to pay for fuel, why not? Why is there Fedex, why is Boeing building 747 and 777 freighters? Some people will pay good money to get their stuff long distances quickly. If power is free, it costs less to go fast, and more people want to.

When fuel is free, you optimize your designs around other parameters. You try to reduce manufacturing costs, or increase cycles per year, or reduce maintenance requirements or the amount of labor man/hours that it takes to run the thing.
"The music business is a cruel and shallow money trench. A long plastic hallway where pimps and thieves run free and good men die like dogs. There is also a negative side."

-Hunter S. Thompson

brickle
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Postby brickle » Sun Feb 03, 2008 8:12 pm

MSimon wrote:Hunter Thompson was always one of my favorites.

He once sent me an e-mail saying he liked my writing.

Of course he could have been ironic.


I'm pretty sure everything Hunter Thompson wrote was being ironic.

nferguso
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The Akron, the Macon, the ... Bussard?

Postby nferguso » Thu Jun 26, 2008 1:50 am

If Polywell's are net Helium consumers, we're in trouble. If they are net producers, let me think: copious helium, vast amounts of heat, fuel is negligible - imagine 100 MPH superdirigibles cruising the stratosphere.

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Re: The Akron, the Macon, the ... Bussard?

Postby blaisepascal » Thu Jun 26, 2008 3:01 am

nferguso wrote:If Polywell's are net Helium consumers, we're in trouble. If they are net producers, let me think: copious helium, vast amounts of heat, fuel is negligible - imagine 100 MPH superdirigibles cruising the stratosphere.


p-B11 Polywells are net producers, each mole of boron used as fuel creates 3 moles of helium as waste.

But not "copious helium". I did a back-of-the-envelope calculation a while ago and it worked out to something on the order of a few metric tons of B11 needed generate the equivalent of the world-wide total electric usage per year. That would generate only a few metric tons of He4 as output. That's not enough to solve our He shortage, so any He used for cooling the Polywell needs to be recycled as efficiently as possible.

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Re: The Akron, the Macon, the ... Bussard?

Postby rcain » Thu Jun 26, 2008 2:40 pm

blaisepascal wrote:
nferguso wrote:If Polywell's are net Helium consumers, we're in trouble. If they are net producers, let me think: copious helium, vast amounts of heat, fuel is negligible - imagine 100 MPH superdirigibles cruising the stratosphere.


p-B11 Polywells are net producers, each mole of boron used as fuel creates 3 moles of helium as waste.

But not "copious helium". I did a back-of-the-envelope calculation a while ago and it worked out to something on the order of a few metric tons of B11 needed generate the equivalent of the world-wide total electric usage per year. That would generate only a few metric tons of He4 as output. That's not enough to solve our He shortage, so any He used for cooling the Polywell needs to be recycled as efficiently as possible.


I too am also a big fan of airships, after all why waste all that energy keeping airflow over a wing up, when Archimedes will keep a load airborne for free.

Not quite up to the calculations, but neutronic problems aside, wont IEC fusion work just as well (if not better) using D + T or even D + Li as fuel - with even more (mole) Helium as a byproduct?

Jeff Peachman
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Postby Jeff Peachman » Thu Jun 26, 2008 3:08 pm

If we're worried about a helium shortage, what can you use to fill the airships?

Without helium you would have to use heated air. The heating is cheap but it doesn't have the same advantage that helium provides with zero energy. I suppose if your reactor fails you will retain enough heat to get to the ground for repairs, but a helium blimp can stay aloft indefinately while you solve that problem.

What is nice, I suppose, is a hybrid airship. It might even be able to provide enough bouyancy to get off the ground all by itself, and at higher speed it might be able to produce enough lift to get to higher altitudes than a conventional airship -- hopefully allowing it to bypass bad weather. I wonder how fast one of these could get with unlimited power?
- Jeff Peachman

rcain
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Postby rcain » Thu Jun 26, 2008 3:44 pm

If you are looking for speed, I think airships are entirely the wrong thing to start with; what they are more likely useful for is for slower moving (bulk) cargo transportation; slightly faster than boats, and they can reach landlocked areas.

An efficiency oriented (hybrid) idea I have been tinkering with is that of combining a sail plane with a balloon: Think of an airship shaped like the sail of a giant yacht; with the right drag vectors, aspect ratio and angle of attack it, it sails through the air even into wind (+/- 20 degrees or so), with no engine at all!

(You'd probably want two connected sails so it can hove-to and steer properly.)

Cant think why it hasn't been tried (any smart comments anyone?)

Jeff Peachman
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Postby Jeff Peachman » Thu Jun 26, 2008 5:25 pm

So you're imagining a balloon shaped something like a pizza wedge?

Rather than having two, why not shape this wedge like a lifting body, with small control surfaces for manuevering.

I wasn't thinking of something in the shape of a zepplin, I was thinking of something more akin to the Aeroscraft. It would need to have a lifting body shape.

Of course drag is much higher, but you would be able to cruise at several hundred miles per hour and perhaps be able to take off and land vertically.
- Jeff Peachman

Jeff Peachman
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Postby Jeff Peachman » Thu Jun 26, 2008 6:51 pm

with the right drag vectors, aspect ratio and angle of attack it, it sails through the air even into wind (+/- 20 degrees or so), with no engine at all!


I may be minsunderstanding what you are trying to say, but a yacht/sailboat can only sail into the wind if it has water to push against. (The "lift" vector points along the bow more closely than the "drag", like how its difficult to paddle a canoe sidewides but easy forward or back).

A sail-plane can only fly into the wind without an engine if it is losing altitude as it does so (gliding). If you add bouyancy, you won't lose alititude, and you need that conversion from potential to kinetic energy in order to overcome the drag of the sailplane as it glides. So a sailplane-balloon hybrid without an engine is just a skinny balloon with wings.

In the end we're both thinking about plane/balloon hybrids, except it seems as if my version is more balloon than plane and yours is more plane than balloon.

Let me know if I completely misunderstood what you meant though.
- Jeff Peachman

ravingdave
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Postby ravingdave » Thu Jun 26, 2008 8:13 pm

Jeff Peachman wrote:
with the right drag vectors, aspect ratio and angle of attack it, it sails through the air even into wind (+/- 20 degrees or so), with no engine at all!


I may be minsunderstanding what you are trying to say, but a yacht/sailboat can only sail into the wind if it has water to push against. (The "lift" vector points along the bow more closely than the "drag", like how its difficult to paddle a canoe sidewides but easy forward or back).

A sail-plane can only fly into the wind without an engine if it is losing altitude as it does so (gliding). If you add bouyancy, you won't lose alititude, and you need that conversion from potential to kinetic energy in order to overcome the drag of the sailplane as it glides. So a sailplane-balloon hybrid without an engine is just a skinny balloon with wings.

In the end we're both thinking about plane/balloon hybrids, except it seems as if my version is more balloon than plane and yours is more plane than balloon.

Let me know if I completely misunderstood what you meant though.



I think his idea is related to those "spray gliders", which are in my mind a brilliant invention. They work by changing boyancy. When they are heavy, they dive downward using the wing to glide horizontally. When they get to a predetermined depth, they increase boyancy, making them lighter than water. They then glide up to the surface using their wing to make them move horizontally. All in all they can travel hundreds of miles using very very very little power.


Here's a link.
http://www.whoi.edu/instruments/viewIns ... do?id=1498

In any case, if the concept works in water, a similar concept should work in air.


David

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Postby rcain » Thu Jun 26, 2008 9:50 pm

Jeff Peachman wrote:So you're imagining a balloon shaped something like a pizza wedge?

Rather than having two, why not shape this wedge like a lifting body, with small control surfaces for manuevering.

I wasn't thinking of something in the shape of a zepplin, I was thinking of something more akin to the Aeroscraft. It would need to have a lifting body shape.

Of course drag is much higher, but you would be able to cruise at several hundred miles per hour and perhaps be able to take off and land vertically.


Bear in mind, I am just brainstorming here on the fly, so quite likely to miss the obvious (like Newtons 3rd law), but yes - just like a giant pizza wedge - suspended vertically (not horizontal).

The trick (if there is one at all) is in utilizing asymmetry - the aerodynamic reaction from the vertical wing, is used as a propulsion vector, like a yacht, rather than a glider which uses it for vertical lift (we have buoyancy instead for that ). It must exceed the drag in the same direction of travel to accelerate and equals it at terminal velocity.

The critical point you rightly make is that a yacht also has the keel in the water providing greater drag in that direction than the forward shape of the hull. Even without that however, the aerofoil will still want to fly. Anyway, just take the yacht out of the water (make it lighter than air) and make the keel asymmetric also and you can get almost the same effect (i think).

Lifting shape might be compromised a bit, but I cant imagine that much.

Control surfaces - yes you could add those, for up and down, trim, etc.

Maybe I'll just sleep on the idea a while longer (or actually sit down and work it out properly).

To RavingDave: "spray gliders" - no not what I was meaning, but pretty darn kool idea also :)

Just because we can produce lots of energy doesn't mean we should waste it - thats what's got the world into its current ridiculous condition already. IMHO.


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