How do jump drives really work?

[HG_B]

Otherwise, why not just say "Read the MGT Core Book"?


Hans

Well as that IS the latest Marc approved rule set for how the Trav universe works, that would be valid.

 

[rancke]

Well as that IS the latest Marc approved rule set for how the Trav universe works, that would be valid.

Go ahead and do that, then. Meanwhile, I'll continue discussing the question with those who disagree with that approach. Are you going to join us?


Hans

 

[Cryton]

Who is to say that the consumption of Jump Fuel is an inefficient process?

IMO you are over-clocking your powerplant and consuming a lot of fuel to rip open a hole/portal/whatever in the fabric of the universe and launching a ship through it. That IMO, and that of astrophysics, requires an immense amount of power on an nearly unimaginable scale. Over-clockable Fusion Powerplants seem to be the most efficient way to do so, as it takes less time to refuel a hydrogen tank for the next jump than using solar collectors to charge a capacitor bank, especially as you might have to deal with situations where the local star is not providing you with the same energy that a G2V type star does at 1AU (what the power gen rules for solar collectors are based on. as an example ,try using a solar cell powered calculator by starlight). As for maintaining a Jump field/Jump bubble, isnt it stated that the POwerplant does that once Jump has been initiated?

Personally I don't care if your using Jump bubbles, Jump plates, Jump Grids, or a combination of them all as the universe is a BIG place and all three are there, as all three styles of drive are cannon.

Finally, Its all handwavium, and I for one am willing to wave my hand and play.

Just my .2Cr

 

[E.D.Quibell]

It doesn't state all is used. ONLY all is sucked out of the drop tank. Part of the J-drive could just as well have a small reserve tank.

It could. However it doen't state this either. It is completly valid to designe a ship that has all it's Jump fuel in drop tanks and use all of this fuel prior to jump.

In MGT the PP supplies power to the J-drive during jump.

It appears that you haven't delved into the rule material from either of the versions I mentioned as you were unfamiliar with those core rules.

I suggest becoming familiar with those rules in order to better parse this problem. That is not to say that there won't be differences. HOWEVER, the answer as to whether or not you can just use power from the capacitors for jump is CLEARLY answered.

O but it isn't ... and that's the issue

Best regards,

Ewan

 

[E.D.Quibell]

Page 58 MT Referee's Manual: "Jump drives are themselves a special high-yeild power plant linked to an intergral net in the craft's hull for initiating and maintaining the jump field. Because a jump drive is also a power plant, it must be allocated fuel seperate and distinct from the craft's power plant."

Suggesting that not all fuel is used at jump entry.

MGT Main Rule Book pg. 141 "To Jump, a ship creates a bubble of hyperspace by means of injecting high-energy exotic particles into an artificial singularity. The singularity is driven out of our universe, creating a tiny parallel universe which is then blown up like a balloon by injecting hydrogen into it. The Jump bubble is folded around the ship, carrying it into the little pocket universe."

So, as you can plainly see, my explanation is in accordance with 2 official version of Traveller and is therefore Cannon.

Yup, and also using all your fuel before jump is cannon (drop tanks), and using solar collections for jump is cannon (annc nova), as well as jumping without a power plant (CT 1st).

So how dose a Jump drive really work?

Best regards,

Ewan

 

[rancke]

Who is to say that the consumption of Jump Fuel is an inefficient process?

It is if all of it is converted to energy and waste heat. Less so if some of it is used for other purposes. That's one of the controversies. If it takes as many cubic meters of hydrogen as is claimed to provide the amount of energy that the capacitors are said to be able to store then the process is extremely inefficient.

IMO you are over-clocking your powerplant and consuming a lot of fuel to rip open a hole/portal/whatever in the fabric of the universe and launching a ship through it.

That works if you ignore the canonical statements about how much energy the capacitors can store.

As for maintaining a Jump field/Jump bubble, isnt it stated that the Powerplant does that once Jump has been initiated?

I'm unsure if it's stated anywhere or if it's an assumption used to explain why CT ship construction rules (and others?) require a power plant factor that is at least equal to the jump drive factor.

Personally I don't care if your using Jump bubbles, Jump plates, Jump Grids, or a combination of them all as the universe is a BIG place and all three are there, as all three styles of drive are canon.

Finally, Its all handwavium, and I for one am willing to wave my hand and play.

Good for you. Meanwhile, some of us enjoy trying to come up with a self-consistent explanation that doesn't have huge loopholes that you need to handwave away.


Hans

 

[E.D.Quibell]

Sounds like you are referring to a rule from the earliest days of the game before Marc wrote updated rules. So, like the rule in 1st Ed that stated that JDs used all fuel regardless of jump distance, this too has been amended in later editions of the game. Why have new editions if not to update rules?

But those rule updates may not make the game more realistic, they may make it just more playable. And that of course is where the issues come in. MgT may be more playable, at the expense of palyers and referees having to suspend more belief.

Best regards,

Ewan

 

[E.D.Quibell]

As I just mentioned - MT was written by DGP and used their preconceptions rather than rules that had been written (I honestly think the folks at DGP based their rules on 1st edition Traveller because they never upgraded to revised edition/TTB/ST or even HG2 Traveller paradigms.

What much like the guys from Mongoose did with their latest eddition?

Best regards,

Ewan

 

[E.D.Quibell]

And, it was approved by Marc to be the Trav rules set at the time... Just as MGT is today...

Which make all of them cannon ;-)

Best regards,

Ewan

 

[E.D.Quibell]

IF there are Solar sail driven ships, can they be armored? HG being a military based book may ignore sail ships as not useful to the military. Civilian ships might be able to use it but not combat ships.

In the case where you could use paint as your solar collector, yes. You can armor your ship and then paint it with a solar voltaic paint.

Best Regards,

Ewan

 

[E.D.Quibell]

It is if all of it is converted to energy and waste heat. Less so if some of it is used for other purposes. That's one of the controversies. If it takes as many cubic meters of hydrogen as is claimed to provide the amount of energy that the capacitors are said to be able to store then the process is extremely inefficient.

I'm thinking along the lines of the amount of energy needed in a short space of time. Capacitors that can discarge very quickly. And capacitor jumps only come in with black globe generators (& TL15). Prior to this we don't have capacitor jumps, there is no TL stated in the original Annic Nova, so if you so wished you could assume it's jump drives were TL15.

Converting a bunch of hydrogen to usable power in a very short space of time is going to be inefficent is it not?

That works if you ignore the canonical statements about how much energy the capacitors can store.

That's why I'm thinking about the speed of energy release.

I'm unsure if it's stated anywhere or if it's an assumption used to explain why CT ship construction rules (and others?) require a power plant factor that is at least equal to the jump drive factor.

Not that IR.

Best regards,

Ewan

 

[whartung]

Well as that IS the latest Marc approved rule set for how the Trav universe works, that would be valid.

Frankly, this path leads to madness.

Because now there are TWO, arguably THREE, competing "approved, official" Travellers. Gurps, MGT, and T5. (Of course, T20 was not renewed, so it no longer counts).

I do not know how much involvement MWM had with MT, or TNE for that matter, but they were both GDW branded products (rather than licensed products). The branding, at least in my view, lends them more credence as to some value of "official".

T4 isn't GDW branded, but it's the "natural successor" since it's the original rights holder and creators work.

So, if you want a conflict resolution system, you could argue "later is better" but also consider the source. If there's a conflict between T5 and MGT, I'd say that T5 was "accurate". I am even willing to even put TNE off to the side, simply because even tho GDW branded, the game mechanics and World View of that system are so wildly different from the original as to be considered an "alternate TU". CT and MT were evolutionary, TNE was revolutionary.

So, in that light, IMHO, the "latest word" on "canon" is most likely T4, even though it is not the latest Official Approved Traveller, simply because whatever "original visions" were captured and manifested by "the creator" of the game, MWM, is still in place in T4 since it's the same person (ostensibly) writing it. MWM didn't put his name on T20, GT, or MGT. But he did put in on T4, and, someday, on T5.

(Please take this all with a grain of salt, just my logic on this matter.)

 

[shadowcat20]

Paint is a interesting idea, but how long would it last? Between re entry for ships that can, battle damage, and space debris it would get scrubbed quickly. Every sandcaster hit on a ship would have the potential to degrade it's collection ability. Then only about 50% of the ship would be facing the light source at any one time so your collection rate would not be that great.

On the other hand, Tech it up so it also absorbs other wavelegnths on top of light and you have a stealth coating that also helps recharge the ship.

As for the Lhyd issue who says it all goes in one gulp? Maybe the ship uses caps to start the process and keeps pumping power into the mix through the use of fuel.

Solar collector ships could generate some sort of field while collecting energy to catch some free hydrogen in space so while they do not have tankage they could still gather up the needed amount to finish the jump. That would explain the long wait times and avoid the quick charge abuse Cap jumping could cause.

Once again I only have CT and T20 to work off of. MT never caught my fancy, T4 was after I stopped playing, and MgT seems like Gurps traveller to me, Same name different game. But then I have not looked into it that much. I suspect T5 will throw all sorts of other monkey wrenches into the works. Or they will decanonize all but T5.

 

[rancke]

As for the Lhyd issue who says it all goes in one gulp?

Drop tanks.


Hans

 

[shadowcat20]

Drop tanks are dumped before ENTERING jump space. If the process takes a few minutes then they can be drained and dumped before the ship enters Jumpspace. They drop before entering, it never states how long it takes to empty them.

A ship burning 10 to 60 percent of its gross tonnage can not do it instantly. That is why I have such an issue with ships just popping their caps and jumping. It can not work that fast. The pumps and lines alone would take up way more tonnage than the drive does.

 

[Ishmael]

Under ships combat page 96 of the MT RM, it states:

"If the ship absorbs enough energy to make a jump and is supplied with sufficent fuel, it may jump at the end of the turn."

This seems to imply that hydrogen is not necessarily used as fuel to generate power. I suggest that it is used as coolant, but not purely for the assumed powerplant.
In the short solar jump example I did to show that solar panels can supply the required power in the appropriate time frame, the 100dton scout required 9Gj of power for jump. When using a normal power plant to power the j-drive, it needed 20dtons of hydrogen.

What if half the hydrogen is used to cool the normal power plant and half is used to cool the jump governor/coil? Rounded off numbers for the sake of ease, why not say it takes 1dton of coolant per 1 Gj used by either. Thus a solar collector requires no coolant, yet the jump coil requires 9dtons.
After all, the coil is processing 9 Gj in a matter of seconds.

This also is needed for regular power plants, but the coolant is vented as hot plasma at a slower rate than a 'hi-yield' unit ( and charges the caps slower too )

This will allow for solar powered ships with the benefit of half the hydrogen used, but at a cost of having an exposed unarmored power source.

This will probably have serious follow-on effects for 'fuel' use and some of the cooling could be handled by proper radiators but the issue of hydrogen as coolant will bring up something Traveller has consistantly ignored..... heat management.

 

[shadowcat20]

Been thinking along those lines for computers also. Who says all that tonnage is the CPU? Throw in I/O stations and CRT's ( Keyboards and screens) and a major part of the tonnage can be stations and cooling for the CPU running very hot due to it's high speed.

 

[rancke]

Any explanation that has part or all of the hydrogen used as a coolant runs up against the simple physical fact that there are other substances that take up less volume per cooling factor (or whatever the correct term is). Things like oxygen and water, to name but two.


Hans

 

[Ishmael]

So?
Both SOM and FFS1 specifically mention the use hydrogen as coolant in jump drives.
If you don't use it as coolant ( and assume that game's use of 'only' hydrogen as fuel is merely a gameplay abstraction ) then you have to explain how fusing so much hydrogen gives up so little power.

It covers the bases with the least number of changes, allows for some interesting ships and it makes sense.

 

[shadowcat20]

Hydrogen is a very simple molicule. Maybe you need something simple to bond with another part of the process. Or form other molicules? Or for that matter go the other way.

It is also very avalible and easy to find. Better compositions may be harder to find, and MUCH more expensive in the tonnage needed.