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A question on Jump

Now here comes a possibly silly question. Why could you not HPGs (Pg 66 of FFS) to discharge power into the Jump Drives? It seems to me that this would reduce the need for Jump Fuel especially once the TL gets high enough to use anti-matter power plants. This would probably not be cost effective for smaller ships but could allow for a larger amount of fuel for manuevering.
 
There are no silly questions, only silly answers, this may be one ;) ...

It depends on just what all that "fuel" is actually used for when jumping.

If it's mostly a waste heat dump for the high temperatures generated to create the jump tear you still need it even if the power is coming from somewhere else.

If it's largely an insulator in the form of a jump bubble to keep the ship from touching jump space, again you still need it no matter how you got into jump space.

If it is in fact just for the production of energy, it's a LOT of energy to expect from a source such as EPG/HPG, though it could be done.

As for anti-matter powered jump-drives the official word is that the known way to create jumps in the Imperium and surrounds ALWAYS requires the fuel (though for exactly what is not made clear). This goes back to High Guard and it's rule that you can jump using the absorbed energy in a black globes capacitors IF you also have sufficient fuel.

Can't recall if FF&S offers an alternative explanation or not.

Hope that helps a little. And a belated welcome aboard :D
 
MegaTraveller had reduced fuel requirements for very high TL jump drives.

The rules can be ported over to FF&S easily enough without breaking anything, since FF&S didn't really cover the TLs above 15 in any great detail - no disintegrators etc. ;)
 
Well using FF&S black globe calcs for a 50000 ton ship with a jump of 3 to generate the 280000 MJ to fill the capaciters would take 9800 cubic meters of HPG which then makes the primary factor of how much MJ from the power plant to you want to devote to recharge and how soon you want the recharge to take place. Which would mean that while civilian ships would not want to devote a lot in order to keep more economical poer plants, Miltary ships would want to devote more.

Now if the 'fuel' is used to generate the power than this theory is blown out of the water and ships need to moderate their bunkerage in order to be able to escape from combat.

If it is an insulator to maintian the bubble than you would only need to replenish if you used the the insulator for other purposes.

If the fuel is actually a coolant than why do you have to replenish after each jump. Simple physics states that as the liquid gets hotter than it turns to a gas which can be explained by having to vent the 'fuel' because a gas occupies more volume than a liquid. But if you cycle the gas an expose to the absolute 0 of space it will cool back down into a liquid fairly quickly so long as you pump the gas outside of the ship and back into it's tanks. Now while you might have some loss in order to keep from blowing out the pipes and filling the ship with a fammable (liquid H or OX) of something that could actually be poisonous, the loss would not be much and again would have to be replenished periodically. This would also explain reduced requirements for higher TL jump drives due to more advanced heat exchangers.

I have also looked at MT explanation and FF&S and have also discovered that FF&S actually requires more fuel than MT up to TL16. MT also states that a JD is comprised of a latice and a High capacity Power PLant but MT does not include rules for HPGs.

Now if a JD is an HPG that is fed by the power plant and sends the nessecary power in a single pulse to the JD to energize the grid, than the 'fuel' requirement would simply be enough to cool the HPG at the moment of discharge which if we are using Liquid H should not be the much.

Any holes in my logic.
 
Another thought?

The masses for JD in FF&S decrease as TL increases and the formula is as follows:

Total volume of drive * 5 / divided by Max Jump for drive.

The impression I am getting from FF&S is that the Max Junp is for the ship's drive (ie max jump for a TL15 JD is the same as that for a TL 13 - 4). Is the correct understanding or should the max jump be the TL max for the drive which for TL 15 would be 6?
 
Originally posted by Laird Dun'Afton:
Any holes in my logic.
Yes, now that you mention it.

You're trying to apply logic to an artifact in the role playing game, an artifact that has never been detailed or explained at the level your conjectures presume by the way.

What is jump fuel used for? The answer is; We Do Not Know. Look at the various versions:

- CT gave us a black box with size and dTon limits. Input X, Y happens, and no other details. CT also presented a few alternate drives; the Annic Nova 'fuel-less' version and the early Terran 'fuel hog' variety.

- MT fiddled with fuel requirements, added a hull grid, and 'explained' what zucchai crystals were for. MT's explanation of fuel usage is troubling. While we're bending physics already with gravitics and an FTL drive, MT's fast burn reactor is just plain silly.

- TNE got a bit more technical and presented other FTL drives, but the question of where the fuel goes wasn't answered.

- T4 went back to CT.

- GT and T20 have wisely ignored the whole topic.

Can everything you wrote and suggested work? Sure why not? Just as long as it is IYTU. Whether it will work in anyone else's TU is a matter of the conjectures they make.

Whatever you come up with is fine IYTU. Whether it will work in the OTU, and that shouldn't hobble YTU, is another question.

Here's a question you may want to ask; How does an understanding of jump drive at the level I'm proposing actually help my group's gaming experience?

If you can't answer that one, you're just spinning your wheels.


Have fun,
Bill
 
Originally posted by Laird Dun'Afton:
IYTU? OTU? YTU? I am not familar with these abrevs.
What sci-fi convention do you chair?

OTU - Official Traveller Universe. A setting which tries to use all canonical materials as published. (An impossibility because canonical materials themselves are inconsistent.)

YTU - Your Traveller Unvierse. A setting tailored for the needs of your gaming group. Personal TUs differ from the OTU and from each other. Each personal TU is different, all are good.

MTU - My Traveller Universe. See YTU above.

IYTU, IMTU, etc. - In Your Traveller Universe, In My Traveller Universe, etc.

Hey I said it was a techie question.
So what? Tell me how to answer a techie question when 1) You don't what the hell the technology is and B) You don't know how the hell the technology works?

Can 3 million hamsters on exercise wheels power a jump drive? Why does the Imperial standard drive need lots of hydrogen but the Annic Nova drive doesn't? Can a psion power a jump drive? (FF&S says yes) Why did the original Hiver jump drive 'melt down' after a number of uses? Who knows?

While you're at it explain gravitics, pisonics, waste heat management, and dangerous lasers with a range measured in light-seconds too.

We have no real facts so we can't even make anything but the most general suppositions. Come up with something that satisfies the needs of your gaming group. That's all that matters.

It's a game artifact after all.


Have fun,
Bill
 
Originally posted by thrash:
Quibble: hull grids date to Marc Miller's "Jumpspace" article in JTAS #24 (pp. 35-36). They are at least implied by the "jump ship" in Supp. 9 (p. 22).
True, although somehow the game fails to reflect that fact in ship combat. Hull damage never effects a vessel's jump rating except by destroying the vessel entirely. Odd, no?

And, hull grids can be implied from CT's jump ship description. You can draw other implications too.

The cables are said to 'extend' the ship's jump field and care is taken to point out that bigger extensions mean smaller jumps. Because the jump ship routinely carries irregular sized loads, unlike a battle rider tender for example, the shape of the vessel's jump field cannot be 'preset' when her drives are constructed. Special cables are used to change the size and shape of the drive's 'preset' jump bubble. Cables or a grid embedded in the hull are thus not necessarily part of a regular jump drive package.

YMMV.

I don't like jump grids and I don't like DGP's silly 'different empires, different patterns' bit too. Portions of a jump drive extending into and byond a vessel's hull? Yes. A ship looking like it's been wrapped in glowing blue graph paper? No.


Have fun,
Bill

P.S. LAD: YMMV means your mileage may vary.
 
Originally posted by thrash:
That's not true: the Hit Location table in Book 2 (p. 30) is nicely ablative.
Hmmm. The damage table on Page 30 of LBB:2 reads in part:

Two
Dice - Starship
2 - Powerplant
3 - Maneuver
4 - Jump
5 - Fuel
6 - Hull
7 - Hull

etc. (emphasis mine)

The damage definitions on Page 32 read:

Drives and Power Plants: Each hit on a drive or powerplant reduces its letter classifiaction by one. Thus C becomes B...

and:

Hull: A hull hit decompresses the ship's hull. Further hits have no effect. (emphasis mine)

Hull hits are quite different from jump hits, even in LBB:2 combat.

Oh, you mean High Guard and its descendents? Have to agree with you there.
Seeing as the MWM Jump Space essay post-dates HG2, yes. But you can also see that LBB:2 has much the same results. Is there any version of Traveller ship combat in which a hull hit or cumulative hull hits degrade jump performance? Degrade jump performance before destroying the entire ship that is.

All of this is moot however. The only things that matters is how you do it IYTU.


Have fun,
Bill
 
Originally posted by Laird Dun'Afton:
IYTU? OTU? YTU? I am not familar with these abrevs.

Hey I said it was a techie question.
Please explain how exactly an Atomic reactor works, the complete cycle of 1 molucle of H20 from when it becomes a rain drop to when it becomes a rain drop again.


Point is Explain how you want to in your Role Playing Game. If you have characters that want to know exactly how it works, suggest that those characters become scientist and role-play research it out.

Some times the fun of the game gets lost in the details


Dave
 
Laird D'A:
...If it is an insulator to maintian the bubble than you would only need to replenish if you used the the insulator for other purposes.
That's assuming you can recover the gas when you drop out of Jumpspace. I can imagine that the gas needs to be replenished during Jump as it, erm (waves hands) percolates out of the J-field, and any left at the end of your J will be lost to hard vacuum upon return to realspace.
If the fuel is actually a coolant than why do you have to replenish after each jump. Simple physics states that as the liquid gets hotter than it turns to a gas which can be explained by having to vent the 'fuel' because a gas occupies more volume than a liquid. But if you cycle the gas an expose to the absolute 0 of space it will cool back down into a liquid fairly quickly so long as you pump the gas outside of the ship and back into it's tanks.
That's true if the Jumpfield-bounded space remains at near-absolute-zero throughout the week. If heat cannot easily cross the jumpfield barrier to be lost in J-space, the volume inside the J-field will get hotter and hotter until you can no longer cool the J-drive. So the gas has to 'percolate' across the barrier, carrying enough excess heat to keep the ship comfortable. Now, since ships' exteriors can get pretty hot without damage, it might be feasible to say that in YTU, the space between hull and J-field actually becomes filled with a quite high-energy plasma by the time the journey is complete, and the dispersing clouds of cooling hydrogen would leave traces of Jump-emergence for quite some time, as well as the gaseous eruption being detectable.

On energy transfer, though, out of the J-bubble, what sort of permeability does the J-field have? Does it let energy out efficiently?
 
Originally posted by DaveChase:
Please explain how exactly an Atomic reactor works, the complete cycle of 1 molucle of H20 from when it becomes a rain drop to when it becomes a rain drop again.


Point is Explain how you want to in your Role Playing Game. If you have characters that want to know exactly how it works, suggest that those characters become scientist and role-play research it out.

Some times the fun of the game gets lost in the details


Dave
Sorry about being so blunt. Didn't mean it to come out that way.

I just wanted to make the point of saying, role play for role playing. Make sure that there are some universial secerts that can never be found out.

Or put the players through hell and back to find it out. Like 80+ 4hour long game sessions focusing on find the answer before they die on some out of the way planet with the answer but can't tell anyone


Dave
 
Sigg,

Apparently any jump drive explanation is full of holes or credibility gaps (apocryphal?), although I did like that multi-post enough to consolidate and HTMLize it.

Rob
 
Bill Cameron

What sci-fi convention do you chair?

I have just been asked to become the Gaming Director for SheVa Con in Roanoke VA. Wanna Come?
 
Originally posted by DaveChase:
Please explain how exactly an Atomic reactor works, the complete cycle of 1 molucle of H20 from when it becomes a rain drop to when it becomes a rain drop again.

Point is Explain how you want to in your Role Playing Game. If you have characters that want to know exactly how it works, suggest that those characters become scientist and role-play research it out.

Some times the fun of the game gets lost in the details

Dave
Not to nitpick or anything, but in the Navy, you are expected to know a LOT about how the ship works. Theoretically, someone who's been on board a ship for 3 years with a paygrade of E5 or higher should know how to operate just about any of it. Not saying they become experts at it, but even the CO knows how the steam cycle works and what the ship can and can't do.

This level of knowledge used to be something that a person could do on their own initiative and get basically extra credit come advancement time, but about the time I was getting out, they decided to make it mandatory for us to advance. I'm sure the intention was to allow us to be swapped around in case it became necessary, and to give us busy work learning all that crap (takes typically 18 months to learn it), but it wound up being a major discouragement, and those who'd done it on their own and actually knew their shit were now joined by people who basically got handed the qual for half the work. Devalued what was the sign of a good sailor who wanted to make the navy a career.

At any rate, any crewmember on a spacecraft should have fairly good information on how stuff works, because things can go really wrong in a hurry up there.
 
Please explain how exactly an Atomic reactor works,
Certain materials in close proximity start a cascading reaction whereby the change in mass is converted to energy. If you keep this running at a rate by which it maintains heat output, but does not reach a bursting point, then that heat can be used to boil a kettle. The steam from the kettle spins a turbine, inside the turbine are magnets. Spinning magnets cause an electronic flux in a nearby coil.

Do you want to know MORE?

Not like it's complex. Early high school chemistry and physics covers all the concepts needed to build one.
 
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