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How do jump drives really work?

just for general info, blackbody radiators can radiate away only 56.7KJ/sec per square meter.assuming a temperature of 1000K, Higher temps are possible, of course, but if your using the steam turbine model that FFS1 says is in use, you'll end up lowering the carnot eff of the turbines and thus, of the power plant's ability to generate real useful power. At 2000K, they would dissipate ~.907Mj/sec per m^2, but lower the power plant's eff to 20% unless you raise the high reservoir side higher, be remember that there are limits to how hot you can go, even with Trav materials ( tungsten- ~3700K and tantalum hafnium carbide at ~4500K )

The direct conversion set-up should avoid this issue as its not a heat engine, strictly speaking. and for far future, we might assume eff's upwards 90% perhaps.

J-drive requirements aside, reaction based thrusters can dump their waste heat out with the exhaust plume ( standard Trav m-drive doesn't have that option ) and normal ship's power requirements aren't as great and might be satisfied with a smaller power plant that uses caps to provide dynamic headroom for periods when extra power is needed. I'll assume weapons/shields have dedicated power plants that are normally off and undergo cold start to 'idle' during general quarters and given a warm start to full operation when weapons are unlocked for firing.

It should be obvious that cooling is an issue that goes beyond any simple jump drive discussion.
 
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Radiant fins could be filled with liquid helium or another substance to help them transmit the heat maybe. God help you if you are in a hot part of space like a nebula, esp at 1/10th G acceleration. I prefer the direct energy conversion idea, steam turbines seem adapting old tech to thousands of years in the future.
 
Quick question,

What happens when you vent large amounts of heated H2 into cold space? Large amounts of heated H2O would form Ice sheets. Now Not sure about H2 but large blocks of frozen water in space would form Nav hazards after a while. A jump 4 100Kton ship could leave a block of ice up to 40Ktons in size in place when it jumped. Also could a mass of Ice that size affect a jump due to it's proximity to the jumping ship?
 
Large amounts of H2 should, pretty much, dissipate if you're in the inner system; it's blackbody radiation will be insufficient to keep it below thawing, and once liquid, lack of pressure will vaporize it pretty quick.

The water, depending on where in system, how fast, in how big a chunk, and how hot the water is, might freeze into a large chunk, or a zillion tiny ones, or might even just boil off. Inside the ecosphere of the star, it's likely to simply vaporize. If you're using it for coolant, odds are good its 350° superheated steam....

But any dumping overboard produces thrust...
 
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Yes, that was the one instance I was referring to.
And happens to be the definitive work on the subject.


Name three.
Annic Nova double adventure, JTAS (Annic Nova adventure ;), Jumpspace article


Are you familiar with the concept of preponderance of evidence? If 80% of the canonical reference says one thing and the other 20% says something different, you go with the majority of the evidence, unless there are reasons not to.
Trouble with Traveller ship technology is you can't get 80% of the evidence to be consistent.
CT LBB2, HG1, HG2, CT LBB2 revised, MT, TNE, T4 they all do things differently in some fairly important way.

So maneuver drives are thrusters and not reaction drives, jump uses 10% of tonnage per jump number and not 5*<jump+1>, stramlined designs are not 20% less roomy than their unstreamlined counterparts, etc. etc.
M-drives being thrusters is yet another DGP invention from their house setting. So we keep that in the body of OTU canon but discount the lower fuel usage?

Aside - you do know why the fuel required was lowered in MT don't you - it was so the math added up when you designed ships. Yup, they changed a core jump paradigm just so the fuel needed by the Striker based power plant fuel requirements would fit. Sandbox.



So what? The fact remain that building jump-6 designs require TL15.

Not if you go by the LBB Tech tree they don't.

Not if you use the LBB2 ship construction rules they don't.


HG explicitly grandfathers Book 2 designs precisely because they are incompatible with the HG paradigm.
Really - that term must be missing from every copy of HG and HG2 I have. Because in HG2 it explicitly states:
"It is possible to include standard drives (at standard prices) from Book 2..."
Oops - guess someone should have pointed out to GDW that they had made HG and LBB2 drives incompatible the moment they included the drive potential typo in original HG.

It's not just the standard. According to the ship design rules, it's the only available option.
Yes, but the design rules for jump drive variants may have made it to a JTAS article at some point.
It's pretty simple to come up with them really and make sure they don't break the setting.


The average is irrelevant. Given the right conditions, it can be done in one week. Therefore it can be done in one week.
Of course the average is relevant - this is a game where a d6 is used for every rng

Yes it can be done in a week in ideal conditions, but on average takes 3.


That's when you use solar collectors to provide the power. There's nothing magical about the electricity you get out of solar panels. It doesn't come with a aura that makes it different in any way from electricity generated in any other way. Therefore any other kind of power generation contraption can charge those special capacitors in the same time solar can charge them when conditions are optimal.
Yes, at a day and a half per jump number.


That's silly, because solar panels are among the things we know enough about to estimate the size of (not to mention that several of the rules sets provide stats for solar collectors). But it really doesn't matter, because I'm not talking about using solar collectors, I'm talking about substituting a plain old simple fusion generator for the solar collectors.
Have you seen the size of the solar panels on real world space stations? Now build in machinery to regularly deploy and retract said panels.
Didn't someone point out a few chapters back that the design rules for sollar arrays are rubbish?
But you are missing the point - I would make the accumulators the bulky bit of the solar collector based jump drive so that a ship can not be built economically that uses the slow accumulator technoolgy and fusion power because it costs so much.

Let me repeat that, since it's pretty crucial to my argument: I'm talking about the ramifications of having a jump drive that can be powered by a relatively small amount of power over several days. If the Annic Nova's solar collectors can collect enough electricity to power its jump drives in a week, then a power source that delivers the same amout of electricity in a week can do the same. Is that clear?
Very.

You just seem to be missing my point that the design rules can be written in such a way to make sollar collector based craft a lot more expensive to operate in the long term, and hybrid craft even more prohibatively so.

Which is why the major players in the OTU all go with hydrogen.


That's wrong for a start, because the jump drive has done its job once the jump has been initiated[*], but even if the drive was still busy, the capacitors would still be empty.
Nope - not wrong at all.
The jump drive still has a job to do in jump space.

Once again - the meta game design rules would forbid charging accumulators in jump space.

Can you charge regular drive capacitors while in jump space?


Depends on its size, don't it? The equivalent of what a solar sail of the size carried by the Annic Nova can collect in a week under optimum conditions. The ship isn't going to run its maneuver drive or fire its weapons while in port, is it?
Still going to be an awful lot of waste heat.


You think that would be beyond the capability of futuristic technology? What's the problem with hooking up a water pipe and a drain?
LOL - you really think it is as simple as throwing buckets of water over the reactor to cool it?

Though a hookup to a power main would be simpler.
And you get free electricity from where exactly?


Depends on how much fuel you need.
A lot - I'll run the numbers later today

I sincerely doubt that.
Doubt away - but until someone runs the numbers it's just your bias and gut feelings versus proof.


All references to the Annic Nova, including TNS newsbriefs, are from the same single source, the adventure.
Which firmly place the Annic Nova in the OTU - not some generic ATU.

Would that I could explain it. And I would never ignore it. If I could explain it, I would use it. As it is, I'm advocating retconning it.


Hans
I can explain it.

Even better I can design the rules to build the things in LBB2 or HG terms.

I am advocating keeping it and maintaining the richness and diversity of the OTU.

Retconning has always been the lazy way out for me.
 
Quick question,

What happens when you vent large amounts of heated H2 into cold space? Large amounts of heated H2O would form Ice sheets. Now Not sure about H2 but large blocks of frozen water in space would form Nav hazards after a while. A jump 4 100Kton ship could leave a block of ice up to 40Ktons in size in place when it jumped. Also could a mass of Ice that size affect a jump due to it's proximity to the jumping ship?

Space isn't cold the way most people think of cold.

It is a vacuum and the only way to lose heat is by IR radiation.

Dumped water would vapourise as soon as it enters the vacuum.
 
(What volume is that? The volume in the MT, TNE, and T4 rules are radically different from the volumes in HG, T20, and MGT (and both differ from those of Book 2).)

Let me rephrase the question, then. Does it make sense to you that they don't carry along the hydrogen for their power plants in the form of water? Can you come up with an explanation, not invoking alternate physical laws[*], that makes sense?

[*] Can you come up with a self-consistent alternate physical law that would explain it, for that matter?​


Hans

I can give you two reasons, through I'm not sure if they outweigth the advantages of a slightly decreased volume requeriments:

- If you skimm fuel from a GG, is there enought oxigen to convert it on water? (again, I have no scientific data, just a thought)

- While carring Hyd in form of water whould save volume (1/9 ton/kl vs 1/13.5-14, depending on the version), it whould add weight (1 ton/kl vs 1ton/13.5-14 kl). While most traveller versions just ignore weight, I don't think it could be so easly ignored (except with alernate physical laws such as the ones traveller gives us :D). In the versions I know (CT, MT, T4, MgT) only MT really cared about weight, and the only real limitation it gave was for agility, that used to be low anyway.


See, there's where I think there's a difference between game rules and the "reality" of the background universe. Do the people in the OTU really not carry along the hydrogen they need for power plant use in the form of water? Or is it just that the very simplified rules got it a bit wrong? And do the power plants really gulp down tons of hydrogen per week in order to provide life support, maneuver, and energy weapons, and if they do, do they really use the same amount of hydrogen regardless of whether they're cosily ensconced in jumpspace or moving at full speed with guns blazing 24/7? Or are the rules just a tiny bit simplified and not totally realistic here and there?


Hans

At least on MT, existed the idea of extenden endurance, which meant the time your fule whould last using no weapons, agility nor maneover over 1G, opposed to combat power, which meant PP at full power to power all ship's systems. EDIT: MajorB's citadel class assault ship, discussed on another thread, worked on this principle.


Large amounts of H2 should, pretty much, dissipate if you're in the inner system; it's blackbody radiation will be insufficient to keep it below thawing, and once liquid, lack of pressure will vaporize it pretty quick.

The water, depending on where in system, how fast, in how big a chunk, and how hot the water is, might freeze into a large chunk, or a zillion tiny ones, or might even just boil off. Inside the ecosphere of the star, it's likely to simply vaporize. If you're using it for coolant, odds are good its 350° superheated steam....

But any dumping overboard produces thrust...

But you can dump it on several directions and neutralize this thrust...
 
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Concerning H2O vs H2 for tankage, I prefer to go with H2.

If a ship has tanks of H2 then there is a real risk of ships running out of air.

If you store water in the tanks, How hard would it be at higher tech levs to Break it down and keep the Oxy while using the H2 to fuel the process? Ships could last a long time turning water into heat and air.

Seems to be more in line for a space game to have a risk of air loss in the game.
 
It would be redundant to make water then break it back down for hydrogen to be used as fuel. Water storage would have it's own problems, such as become a vector for bacteria...

LH2 seems much more sanitary.

Pure water is not a good place for bacteriae to grow. Lack of nutrients and low osmothic presure whould kill them.

If used as coolant, spread water vapor or droplets of water (such of that of conditioning air) are a good place for them to grow, as it sin't usually pure water and it's warm water (this is how legionella usually spreads), but superheated waer vapor such as we are talking here (someone said about 350 º C, I've not checked it) whould be sterille. Also, to grow, bacteriae needs atmosphere (they may live without oxigen, if anaerobic, but I don't think they could live without other gases).

Used as reserve of hyd, water could't be pure (electrolysis cannot be done with destilled water), but the salts used to make water conductive won't allow bacteriae to grow.
 
Pure water is not a good place for bacteriae to grow. Lack of nutrients and low osmothic presure whould kill them.

If used as coolant, spread water vapor or droplets of water (such of that of conditioning air) are a good place for them to grow, as it sin't usually pure water and it's warm water (this is how legionella usually spreads), but superheated waer vapor such as we are talking here (someone said about 350 º C, I've not checked it) whould be sterille. Also, to grow, bacteriae needs atmosphere (they may live without oxigen, if anaerobic, but I don't think they could live without other gases).

Used as reserve of hyd, water could't be pure (electrolysis cannot be done with destilled water), but the salts used to make water conductive won't allow bacteriae to grow.

Think about the fact though that one of the things that eat ships at the bottom of the ocean is bacteria, now think of going to a thousand different oceans and pumping water in from them....

Each ocean or any other body of water you are going to have to run rudimentary decon, even then you might not catch it before it eats a hole in your tank. Bacteria can live at 350F as well, look around the ocean vents.
 
Think about the fact though that one of the things that eat ships at the bottom of the ocean is bacteria,

Actually, it is salt water corrosion. Bacteria don't do well on a diet bonded superdense non-reactive metal or, titanium for that matter. The periodic table will give you some clues as to what isn't happening.
 
its not salt water corrosion

http://shkrobius.livejournal.com/49484.html
http://peculiarvelocity.wordpress.c...-the-tevatron-the-next-hollywood-blockbuster/
http://news.blogs.cnn.com/2010/12/11/new-metal-eating-bacteria-found-on-titanic/
http://findarticles.com/p/articles/mi_m1200/is_20_164/ai_110963009/

that's not counting bacteria that eat petroleum, plastics, rubber and concrete and jet fuel and.......

don't underestimate bacteria and what they can eat and what conditions they can live in.
 
Nor does it count the bacteria and other life forms living in hyrdrothermal deep-ocean vents at temps of up to 465°C and Ph down as low as 2.8 (as acidic as vinegar)...
 
Think about the fact though that one of the things that eat ships at the bottom of the ocean is bacteria, now think of going to a thousand different oceans and pumping water in from them....

Each ocean or any other body of water you are going to have to run rudimentary decon, even then you might not catch it before it eats a hole in your tank. Bacteria can live at 350F as well, look around the ocean vents.

its not salt water corrosion

http://shkrobius.livejournal.com/49484.html
http://peculiarvelocity.wordpress.c...-the-tevatron-the-next-hollywood-blockbuster/
http://news.blogs.cnn.com/2010/12/11/new-metal-eating-bacteria-found-on-titanic/
http://findarticles.com/p/articles/mi_m1200/is_20_164/ai_110963009/

that's not counting bacteria that eat petroleum, plastics, rubber and concrete and jet fuel and.......

don't underestimate bacteria and what they can eat and what conditions they can live in.

True, but all those bacteriae need two things: somthing to eat and breath and that the water they're on has some osmotic presure. Pure (destilled) water has none.

Even the strangest bacteriae need something to live on (feed). Some of them may use metals or sulfures (or even stranger food), but they need something to make them react for the chemical reactions we know as life. Some of them need ocigen, others are anaerobic, but need some form of energy (solar, thermal, etc) to live, and nearly all (if not all) need carbon and nitrogen (except por some bacteriae newly discovered on some lakes, all life needs C, O, H, N).

Also I told about osmothic presure. Any bacteriae submerged on destilled water whould absorb this water by osmosis and explode (cellular lysis).

EDIT: As you see, I assume water taken into fuel tanks (if any) is destilled, be it by producing it with hydrogen and oxigen or by destilling it when pumping from an ocean. If you fill your tanks with water taken directly from the sea, I guess bacterial corrosion whould be the least of your problems.

Nor does it count the bacteria and other life forms living in hyrdrothermal deep-ocean vents at temps of up to 465°C and Ph down as low as 2.8 (as acidic as vinegar)...

True, but those are extreme conditions, and they could not live outside those.

And even so, surgical sterilization is done at 180 ºC.

Anyway (let me shot myself) all I say is about terrestrial bacteriae...

I don't know how other planet's life can be... (for what is worth, not even if it exists...)
 
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True, but those are extreme conditions, and they could not live outside those.

Wrong; they can be cultured in cooler water; most bacteria become dormant when chilled below culturing temps, not dead, too.
 
Rancke, wouldn't the Annic Nova not break the OTU if it were sufficiently high tech? As long as the Imperium can't replicate it, there would only be the one, which shouldn't cause too much trouble. And retrofitting a far higher tech level capacitor or whatever it is the AN uses to take power from a fusion power plant might break it.
 
Rancke, wouldn't the Annic Nova not break the OTU if it were sufficiently high tech? As long as the Imperium can't replicate it, there would only be the one, which shouldn't cause too much trouble. And retrofitting a far higher tech level capacitor or whatever it is the AN uses to take power from a fusion power plant might break it.
Sure, that will work. In fact, it's the solution I've been advocating all along. I went with an Ancient artifact that provided the missing fuel and I still think that's the best way, but if you want to make it an Ancient artifact that can jump without fuel, that works too.


Hans
 
In the black globe section of combat, they say the jump energy sinks are 0.05xVxJn. So a free trader has 0.005x2700x1=13.5 kl of sinks. It also says each kl can store 650 Mw (as we talk about energy, not power, I assume they are Mw hour), so it can store 135x650=8775 Mw hour.

It's per combat round. So 1kl of sink holds 650 Mw for 20 minutes, or 216.66r Mw hours.

13.5kl of sink is thus 2924.99r Mw hours

Regards,

Ewan
 
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