Fuel Bladders

[PsiTraveller]

I have to ask here because at times fuel processing seems to border on magic.
As Dalt mentioned 13.5 m3 of water has 1.5 tonnes of hydrogen in it.
But ocean skimming done by ships has 100 tons of water being skimmed and then all of it being converted into Liquid Hydrogen for use as refined fuel. This is the hand waving part I want to double check.

Assume a 1000 ton J1 ship needing 100 tons of Jump fuel. ignore the few extra tons for power plant for now.)
If you skim 100 m3 of gas giant, or water, or ice and run it through a fuel processor (Let's say you have 5 tons of processing capacity). How much refined fuel do you have the next day?

 

[AndrewW]

Assume a 1000 ton J1 ship needing 100 tons of Jump fuel. ignore the few extra tons for power plant for now.)
If you skim 100 m3 of gas giant, or water, or ice and run it through a fuel processor (Let's say you have 5 tons of processing capacity). How much refined fuel do you have the next day?

It's a highly efficient process with zero waste, so you get 100 tons of fuel from 100 tons of skimming.

Not claiming that it actually makes sense...

 

[Condottiere]

I may have overlooked it's supposed to be under pressure.

So a rubber balloon may not be the ideal container out side of a steel container container.

 

[DALT]

All the cargo hold needs is some protection against the water you intend to use (fresh water ideal, salt water less so) Then the connection from the hold to the purifier just needs a simple bit of plumbing and a small change in local gravity to help the water flow to the exit drain from the hold (no need for pressurised bladders, but some need for resilient walls and controls.)
Scooping fuel is fast (1d6 Hours), but processing the fuel can take a lot of time - 20 dTons of Fuel per dTon of processor per day. But, given the ship will be in Jumpspace for 7 days a 1 dTon fuel processor will be able to process 140 dTons of fuel (from 94 dTons of water.)

 

[AndrewW]

Scooping fuel is fast (1d6 Hours), but processing the fuel can take a lot of time - 20 dTons of Fuel per dTon of processor per day. But, given the ship will be in Jumpspace for 7 days a 1 dTon fuel processor will be able to process 140 dTons of fuel (from 94 dTons of water.)

If it needs the fuel for jump though...

 

[whtknght]

most of the "Jump Fuel" is used to begin the jump process (punch a hole between n-space and j-space). The rest is used to maintain the jump field for the week you are in jump. The fuel must be available for rapid use. Fuel Bladders are by definition; temporary storage devices. They can not be filled or emptied as fast as the fuel in the specialized fuel tanks installed when the ship was built.

Fuel bladders are designed to be collapsed and stored when not in use. If you were to attach enough plumbing fittings to get the fuel out fast enough for use of the jump drive, they would not be able to be colapsed and stored in a small space when not used. They are just a big rubber bag with one valve installed.

 

[Jame Rowe]

I may have overlooked it's supposed to be under pressure.

So a rubber balloon may not be the ideal container out side of a steel container container.

This is true, and I've had a few people express this with varying degrees of politeness.

However, here's my thought on this issue: this is in the future, at higher tech levels. They may well have invented something with science or technology that fixes or goes around this issue - for example, there could be a different material or usage of materials technology that allows a flexible fuel bladder to stand up to liquid hydrogen without leaking for a certain amount of time, such as long enough to allow a Jump-1 ship to make two consecutive Jump-1s.

Note that this is my explanation, and you're perfectly free to use it or ignore it, but I'm suggesting it so you have the inspiration and the option.

 

[Condottiere]

You'd need a material that would halt expansion beyond a certain point, and demonstrate some traits of kevlar.

So whether by design or accident, having the bladder confined inside a cargo hold isn't a bad idea.

 

[phavoc]

For longer transfer flights by short legged ships like a free trader I would assume they would simply carry containers configured for water transport and store water rather than hydrogen. Carrying hydrogen requires a more sophisticated setup for cooLing and pressure. Not to mention the risk of carrying that as cargo.

By the time you exit jumpspace your tanks would be refilled and purified and you could jump again as soon as you plot your course.

With all the talk of drop tanks, I would assume that there is a similar idea of being able to buy water tanks for say 100Cr per dton and sell them for 50Cr per dton at your arrival system. That makes perfect sense when travelling between set star systems, especially along more heavily traveled jump mains.

 

[whtknght]

That is exactly right. You just transfer the water to the fuel tanks using a hose from the fuel bladders while you are in j-space. Once you come out of jump, take a star fix, plot your next jump charge the capacitors in the jump drive and away you go. Be aware of the fact that are skipping a maintinance cycle by going straight back into j-space for another week.

 

[Condottiere]

In theory, diagnostics should tell you in real time if there might be a problem.

 

[vargr1]

I use demountable fuel tanks and muti-use liquid/gas cargo / fuel tanks, in MTU.

Never liked the idea of bladders that might leak or rupture :?

The US Army has air-droppable fuel bladders.

Given some high-tech materials, I'd assume that Traveller starship fuel bladders would be darn near impossible to rupture.

 

[-Daniel-]

The US Army has air-droppable fuel bladders.

For some reason when I read this I pictured a giant super ball bouncing. :mrgreen:

 

[snrdg121408]

Evening PDT Rikki Tikki Traveller

CT has this system. As I remember, it cost 10% of the converted volume for storage when not in use.

So, if you wanted a 100 ton fuel bladder, it would fold up into 10 tons when not in use. So it's not free, but when not in use, you get most of the cargo space back.

This was a common conversion for those A1 Free Traders that my group used. Most settings, you can't get where you want to go without Jump-2 range.

CT Adventure 5 Trillion Credit Squadron (TCS) p. 13 When not in use collapsible tanks collapse and are stored in the cargo hold and take up 1% of their filled tonnage.

The collapsible fuel tank found on MgT HG 2e p. 36 has the same cost and storage requirement as found in CT Adventure 5 TCS.

 

[Reynard]

"The easiest way to store Hydrogen is in the form of water. 13.5 m3 of Water contains 1.5 Tons of Hydrogen. So a Cargo hold (plumbed into the Fuel purifier), a fuel purifier"

And you would think after a few hundred thousand years of space flight, some race would have tried carrying water instead of hydrogen (can you efficiently scoop water from gas giant atmospheres?). For some reason, every race with fusion plants and jump drives have safely and efficiently carried and uses pure hydrogen fuel dton for dton.

If fuel bladders are being used on some ships so frequently and extensively, where's the cargo to justify the expenses?

 

[vargr1]

"The easiest way to store Hydrogen is in the form of water. 13.5 m3 of Water contains 1.5 Tons of Hydrogen. So a Cargo hold (plumbed into the Fuel purifier), a fuel purifier"

And you would think after a few hundred thousand years of space flight, some race would have tried carrying water instead of hydrogen (can you efficiently scoop water from gas giant atmospheres?).

Yes, yes you can,

For some reason, every race with fusion plants and jump drives have safely and efficiently carried and uses pure hydrogen fuel dton for dton.

Because the people who wrote it decided that it was that way, and continued it through each edition even after people pointed out that you can store more hydrogen in a ton on ammonia than you can as pure liquid hydrogen. Water-as-fuel has a long history in SF - from Heinlein's torchships to Drake's RCN navy. For a game that prides it'self in it's scientific accuracy, this is a really grating big hole.

 

[-Daniel-]

For a game that prides it'self in it's scientific accuracy, this is a really grating big hole.

The funny thing is, I see the boast of hard science more from the fans than from the game designers. Then those same fans spend tons of effort to prove the game has item X wrong. :lol:

 

[snrdg121408]

Hello vargr1,

For a game that prides it'self in it's scientific accuracy, this is a really grating big hole.

Please provide the source documentation that has the designers of Traveller claiming the rules are scientifically accurate?

As far as I have be able to determine CT Striker Book 3, TNE FF&S, and T4 FF&S has in a majority of cases over simplified the calculations used to create various types of weapons used in the real world.

Okay, I'll rephrase this a bit T Striker Book 3, TNE FF&S, and T4 FF&S has some basis of hard science that has been modified and (over) simplified to fit the designers' framework of the game.

Oops, my apologies for going off topic and I tried removing the post without success. I will return you to the topic of fuel bladders and ask to be contacted off the forum to discuss the tangent I went on.

 

[AnotherDilbert]

Please provide the source documentation that has the designers of Traveller claiming the rules are scientifically accurate?

- All changes should be rational, logical, and scientifically sound (after a!l, Traveller is a science fiction role-playing game).

LBB0, p34.

OVERVIEW OF TECHNOLOGY
Traveller makes certain assumptions about the nature of future technological developments. In addition to the pro- gressive refinement of existing equipment and methods, several areas of future technology have been postulated. Traveller bases its technology on a series of logically explainable developments even if they may be far beyond any present science.

MT Referee's Manual, p56

Apart from a few specified magical technologies, most things should be scientifically reasonable, I believe. The rules are of course very simplified, where the limit to too simplified is may lie in the eye of the beholder.

 

[snrdg121408]

Hello AnotherDilbert,

Please provide the source documentation that has the designers of Traveller claiming the rules are scientifically accurate?

- All changes should be rational, logical, and scientifically sound (after a!l, Traveller is a science fiction role-playing game).

LBB0, p34.

OVERVIEW OF TECHNOLOGY
Traveller makes certain assumptions about the nature of future technological developments. In addition to the progressive refinement of existing equipment and methods, several areas of future technology have been postulated. Traveller bases its technology on a series of logically explainable developments even if they may be far beyond any present science.

MT Referee's Manual, p56

Apart from a few specified magical technologies, most things should be scientifically reasonable, I believe. The rules are of course very simplified, where the limit to too simplified is may lie in the eye of the beholder.

Thank you for the references my first and second edition LBBs did not include LBB 0. Of course my eight softcover book set of FFE CT purchased in 2000 does have LBB 0. Again thank you for the information and another apology for not being able to remove my post that has no bearing on fuel bladders.