All Warships Should Have Drop Tanks

[Jame]

More like because the game designers only had roughly 150 pages divided between three little books in which to introduce an entire sci-fi RPG in which you could design characters, ships, worlds, animals, and several other things in order to create a somewhat detailed setting in which to play.

A RPG which, I'll point out, you are still discussing THIRTY FIVE YEARS after it's initial release.

Did GDW know about butane, propane, and various other hydrides? Damn straight, seeing as they owned cigarette lighters, gas grills, and the like.

Did GDW think including other fuels in the game was worth "page price" they needed to pay? Hell no.

Butane is a better way to carry hydrogen around? Tell me something I didn't know in 1978.

Better yet, come up with workable rules for it, apply those rules to the setting, and share the results with us here.

Eeek! Stop getting your science in my RPG! ALL of you! *Pointing at Whipsnade like he is multiple people and multiple bodies in one place*

:rofl: :devil: (This is where the joke ends, by the way. That was humour.)

I always assumed that L-Hyd was what they used because they were writing it for more than just scientists. But remember, I'm no scientist and hadn't read any of the JTAS CT articles until LONG after I'd read the TNE Core book and the GURPS stuff, where drop tanks weren't mentioned.

If there's a way to do what Mssr. Whipsnade suggests in a way that allows us non-scientists to understand it, I'm all for it.

 

[Ackehece]

If hydrogen is the necessary fuel, and jump technology is only sensitive to volume (not mass), why not just store the hydrogen as something like butane? You get about 1/23 of a mole of butane per ml, and about 1/28 of a mole per ml of liquid H2. A mole of butane provides 10 hydrogen atoms - so 10/23 per ml. A mole of H2 provides 2 hydrogen atoms. so 2/28 per ml.

That's like a 6 fold difference.

So why wouldn't a jump 1 ship simply carry 10% of volume for the hydrogen for the jump, and then another 10% volume of butane for 6 more jumps?

Catalytic cracking of butane is 19th century technology, and further is very simple under high temperatures without any catalyst needed (high temperatures easily provided by a hot fusion drive).

Further, storing butane is much easier and low tech than storing hydrogen.

depends... if you are talking liquid or slurry hydrogen you would have better storage density as butane - but Metastable Metallic Hydrogen would be an idea as it is ~12x as energy dense as liquid hydrogen... which would of course be better than butane. It's not to hard to imagine that far in the future we can stablize metallic Hydrogen - and most gas giants have huge layers of the stuff...

 

[far-trader]

...but Metastable Metallic Hydrogen would be an idea as it is ~12x as energy dense as liquid hydrogen... which would of course be better than butane. It's not to hard to imagine that far in the future we can stablize metallic Hydrogen - and most gas giants have huge layers of the stuff...

...but only at extreme pressures. Pressure I find it hard to imagine any Traveller ship surviving unless specifically built for it*

Now canonically we do have ships lurking in ocean depths, and gas giant cloud tops, but not to my knowledge at the depths required for natural metallic hydrogen. And those are heavily armoured ships. Nope, I don't think anyone in the OTU is cruising around in the metallic hydrogen oceans of the gas giants

* and even then I'm not sure, we're talking up to 1 million atmospheres of pressure iirc, 1,000 times that of the deepest ocean depths

 

[Ackehece]

...but only at extreme pressures. Pressure I find it hard to imagine any Traveller ship surviving unless specifically built for it*

Now canonically we do have ships lurking in ocean depths, and gas giant cloud tops, but not to my knowledge at the depths required for natural metallic hydrogen. And those are heavily armoured ships. Nope, I don't think anyone in the OTU is cruising around in the metallic hydrogen oceans of the gas giants

* and even then I'm not sure, we're talking up to 1 million atmospheres of pressure iirc, 1,000 times that of the deepest ocean depths

:rofl:
caught me out. I was hoping no one would notice, but I would think that looking forward that far into the future and with the ability to manipulate gravity you might be able to compress to that density.
it is possible is all I am saying to have much higher hydrogen density than say butane in a HIGH tech environment - maybe the fuel refining compresses it... we potentially have seen an experiment that produced at least 2 liters of Metallic Hydrogen last year (or maybe not-peer review results are out)

 

[warwizard]

I think at the price in most rule sets they should be restricted to single use, low or no g while attached, no jump possible with them attached*, no value when recovered beyond scrap (think sucked down so fast they partially implode) and that not worth the time for dealers so you have to pay a recovery fee to use them. Oh, and an increased risk of misjump when using them of course. With those and possibly some other restrictions on them I might see them allowable in my TU

Unless your tanks have an exteriour pressure applied like in an atmosphere, they will not implode just by removing the interriour pressure. if the exteriour pressure is zero, there is no force to implode or collaspe the tanks.

Now if you are delivering 1/3 of a Niagra worth of LHd and boiling it off to keep your power plant from melting down, you could argue that it's not exactly a vaccuum around the ship any more, might even reach a measurable pressure. The bigger the ship and more fuel is being vaporized, I supposed you could actually reach damaging pressure levels (legend of the sky raiders sized ship)

 

[77topaz]

Unless your tanks have an exteriour pressure applied like in an atmosphere, they will not implode just by removing the interriour pressure. if the exteriour pressure is zero, there is no force to implode or collaspe the tanks.

Now if you are delivering 1/3 of a Niagra worth of LHd and boiling it off to keep your power plant from melting down, you could argue that it's not exactly a vaccuum around the ship any more, might even reach a measurable pressure. The bigger the ship and more fuel is being vaporized, I supposed you could actually reach damaging pressure levels (legend of the sky raiders sized ship)

Something else to consider is the fact that space is never truly a vacuum (not within galaxies, at least), and the fact that the very presence of a ship would cause there to be extra particles. This is just for "normal" space, of course, since I'm not sure whether there are defined physics-rules etc. for jumpspace at all.
Also, it's "interior" and "exterior".

 

[warwizard]

Extra particles yeah but not enough to crush the drop tank. FF&S 2 (T4) requires armor 5 on the drop tanks minimum compared to armor 20 on the ships, that's still 1 inch of mild steel (nearly, 5 X .5 cm =2.5 cm. 1 " is 2.58 cm). If the hydrogen atmosphere created by boiling all that fuel reaches a few milibars I'd be surprised. The physics just are not there to support collasping the tanks as they are unloaded unless you have significant pressure on them from the outside ("exterior"). Do a jump from planetary surface in a dense atmosphere (ACS class ship = small) and sure the drop tanks will crumple up nicely even if you don't jettison them.

 

[Carlobrand]

If hydrogen is the necessary fuel, and jump technology is only sensitive to volume (not mass), why not just store the hydrogen as something like butane? You get about 1/23 of a mole of butane per ml, and about 1/28 of a mole per ml of liquid H2. A mole of butane provides 10 hydrogen atoms - so 10/23 per ml. A mole of H2 provides 2 hydrogen atoms. so 2/28 per ml.

That's like a 6 fold difference.

So why wouldn't a jump 1 ship simply carry 10% of volume for the hydrogen for the jump, and then another 10% volume of butane for 6 more jumps?

Catalytic cracking of butane is 19th century technology, and further is very simple under high temperatures without any catalyst needed (high temperatures easily provided by a hot fusion drive).

Further, storing butane is much easier and low tech than storing hydrogen.

Occurs to me - very belatedly - that this would make for a dandy ATU method of making commercial shipping more cost-effective. Heck, even water's an improvement, 50% more hydrogen per ml if I did the math right. Smaller tanks, ergo more tonnage available for cargo for the same jump range.

So, we could have two classes of starcraft: a commercial class using these fuels for much greater fuel density and greatly increased cargo capacity but dependent on a starport for that fuel; and a "wilderness" class capable of grabbing hydrogen from gas giants but requiring the traditional-size tanks and therefore with less internal space available for other uses. Question then is which of the available alkanes is easiest and cheapest to manufacture for that use.

If we apply that in MegaTrav, we end with commercial ships that are more massive, therefore slower and less agile than their equivalent-size H2 military counterparts even assuming the same size power plant and maneuver drive.

An interesting thought is a tanker designed so the fuel tank could hold water or liquid oxygen, with the tank having a moving internal partition so that as hydrogen was cracked free of the water, the remaining O2 would be chilled and fed into the other side of the tank. When it came time to refuel, the hydrogen would be taken in and burned with the O2 to create water that would be fed back into the tank. Very difficult technical problems, but conceivable as a sci-fi alternative. Or, if you could figure a way to make methane, ethane, propane, butane or some other alkane from a stock of carbon and hydrogen without a lot of extra equipment and intermediary chemicals, you could use one of those as the fuel, save the carbon after cracking free and using the hydrogen, wilderness-refuel from hydrogen and use the stored carbon to convert the lot into the desired alkane as needed.

 

[whartung]

Occurs to me - very belatedly - that this would make for a dandy ATU method of making commercial shipping more cost-effective. Heck, even water's an improvement, 50% more hydrogen per ml if I did the math right. Smaller tanks, ergo more tonnage available for cargo for the same jump range.

Well, a few points.

1) Perhaps we already have this, but it's called "unrefined fuel".

2) The heavier gases aren't readily available in the upper atmospheres of gas giants, and thus aren't readily skimmable.

3) We do not know whether butane/water can be cracked in to LHyd fast enough to fuel a jump drive.

I have complete confidence it can be processed readily for a Power Plant, it might be fast enough to be used as reaction mass (maybe), but the amount of fuel needed for reaction mass can be efficiently buffered enough to make it viable.

But Jump Fuel -- I dunno. With the large ships, if you go by High Guards "2 turns (40 min) to prep for jump" and it must consume all of the fuel prior too jump, the rate of LHyd consumption for a 100K ship can be measured in "fractions of Niagra Falls per second".

So, I think it works well for the smaller rates of consumption, not so sure for Jump.

 

[HG_B]

If hydrogen is the necessary fuel, and jump technology is only sensitive to volume (not mass), why not just store the hydrogen as something like butane?

You CAN carry it this way. However, the Hy you use for jump has to be usable all at once basically. So, it has to be pure Hy (all of it) when needed. You could carry your 2nd jump Hy in this manner and "purify" it during your 1st jump...

 

[Carlobrand]

Well, a few points.

1) Perhaps we already have this, but it's called "unrefined fuel".

No, unrefined fuel is got from gas giants and water sources, and it can be fed directly into the fusion plant and jump drive, with some increased chance of misjump as a result. There's nothing there saying unrefined fuel is a denser hydrogen source than pure H2, and I'm really not seeing my fusion plant sucking in water and doing the fusion bit. I interpret unrefined fuel as mostly hydrogen with a small percentage of contaminants: helium in the case of gas giants and a bit of water vapor in the case of hydrogen electrolized from water. (Ain't no way I'm putting seawater in my L-Hyd tanks; I figure I'm electrolyzing it and taking the hydrogen in.)

2) The heavier gases aren't readily available in the upper atmospheres of gas giants, and thus aren't readily skimmable.

Which would be why I discussed, "...two classes of starcraft: a commercial class using these fuels for much greater fuel density and greatly increased cargo capacity but dependent on a starport for that fuel; and a "wilderness" class capable of grabbing hydrogen from gas giants but requiring the traditional-size tanks and therefore with less internal space available for other uses." In other words, one class that uses butane or some such as a hydrogen source, buying it at the starport and cracking the hydrogen free on the go, and a second that uses the traditional H2 per the standard game rules.

3) We do not know whether butane/water can be cracked in to LHyd fast enough to fuel a jump drive...

I'm pretty sure it can't be cracked free fast enough under canon rules. As you point out, under the most optimistical interpretation of canon, you've got less than 40 minutes to convert all of it. Flow rate there is something short of monstrous: a quarter percent of the ship's tonnage per jump number per minute. We know the H2 can be delivered at that rate - it's already happening - but whether we can crack hydrogen free of a base chemical at that rate without a majorly big cracking plant that ate up all the space we just gained? That's why I present it as, "...a dandy ATU method of making commercial shipping more cost-effective...": you'd have to scrap and rewrite other elements of canon in order to make it work for jump.

A 200 kt dreadnought would be processing something like 40 dTons per second. Easiest would be to add a requirement for a magic-tech cracking plant, say 1% of the fuel tonnage. That would give the example dreadnought an 800 dT plant responsible for cracking and delivering 40dT per second. Or declare that the jump fuel is consumed gradually over jump instead of all-at-once.

 

[whartung]

A 200 kt dreadnought would be processing something like 40 dTons per second. Easiest would be to add a requirement for a magic-tech cracking plant, say 1% of the fuel tonnage. That would give the example dreadnought an 800 dT plant responsible for cracking and delivering 40dT per second. Or declare that the jump fuel is consumed gradually over jump instead of all-at-once.

I think both of those are rather dramatic canon changes, personally. Simply because of how fundamental volume is to jump, as well as how jump (apparently) works.

The fuel tanker mechanic is, IMHO, less canon breaking, as it doesn't fundamentally break "known laws' of the universe. Rather it breaks unsaid, unknown restrictions on drop tanks (specifically the "canon isn't doing it, there must be some unlisted reason for it").

 

[Vladika]

Eh? Where does it say that a spinal meson gets more than one hit per shot that hits and penetrates as long as the size factor of the target is bigger than the size factor of the spinal?

Spinal Mounts: All spinal mount weapons which hit and penetrate inflict one
extra damage roll (on each appropriate table) for each letter by which their size exceeds 9. For example, a particle accelerator with a code of A gets 2 rolls on both the surface explosion and radiation tables; a factor of B receives 3 rolls, etc. The number of extra rolls is reduced by one for each factor of armor the target ship has (but a weapon always gets one roll). Meson guns are not reduced by armor. - HG p41

 

[Hal]

Spinal Mounts: All spinal mount weapons which hit and penetrate inflict one
extra damage roll (on each appropriate table) for each letter by which their size exceeds 9. For example, a particle accelerator with a code of A gets 2 rolls on both the surface explosion and radiation tables; a factor of B receives 3 rolls, etc. The number of extra rolls is reduced by one for each factor of armor the target ship has (but a weapon always gets one roll). Meson guns are not reduced by armor. - HG p41

In addition? Same page, immediately under that reference on page 41, it goes on to state that batteries of weapons inflict additional critical hits such that for every 1 level of code above that of the target ship, the battery inflicts one additional critical hit.

 

[rancke]

Spinal Mounts: All spinal mount weapons which hit and penetrate inflict one
extra damage roll (on each appropriate table) for each letter by which their size exceeds 9. For example, a particle accelerator with a code of A gets 2 rolls on both the surface explosion and radiation tables; a factor of B receives 3 rolls, etc. The number of extra rolls is reduced by one for each factor of armor the target ship has (but a weapon always gets one roll). Meson guns are not reduced by armor. - HG p41

As Mike told me two posts further along the thread.


Hans

 

[Vladika]

As Mike told me two posts further along the thread.


Hans

Yeah, I need to stop responding to old threads... Bored out of my mind and to much time on my hands. Did start looking into that TL14 BB vs BR thing. Interesting results so far. It looks like you were right all along about the IN knowing that BRs were the better deal.

Raw data so far but you an get about 6 15kt BRs, Me H for about the cost of 1 200kt BB, Me S. (Roughly equivalent to the J vs T controversy, though at the lower TL.)

Did MM and Co ignore their own design rules while sitting around drinking beer and eating pizza or is there another reason the setting and the rules are so off? Or is the setting not complete and the IN has plenty of BR Squadrons further towards Core?

 

[Hal]

Yeah, I need to stop responding to old threads... Bored out of my mind and to much time on my hands. Did start looking into that TL14 BB vs BR thing. Interesting results so far. It looks like you were right all along about the IN knowing that BRs were the better deal.

Raw data so far but you an get about 6 15kt BRs, Me H for about the cost of 1 200kt BB, Me S. (Roughly equivalent to the J vs T controversy, though at the lower TL.)

Did MM and Co ignore their own design rules while sitting around drinking beer and eating pizza or is there another reason the setting and the rules are so off? Or is the setting not complete and the IN has plenty of BR Squadrons further towards Core?

Any answer to that question would be purely speculative

The real issue here, if you want to call it that when we're discussing an imaginary setting *snicker*, is the fact that much of this is all suspended in mid-air (so to speak) without any real supports. No economic rules, no continuity between various authors over a period of time, and last but not least, much of this was done pre-internet era, where relatively quick correspondence was not the norm. We can do our own analysis and make our own assumptions, but until you get a group of people working together using a unified background and set of rules - you're not going to get consistent results.

As has been remarked elsewhere, we're still discussing the rules some 30 years after they've been published. So, it can't all be bad. It may need a tune up here or there, but it can't be all bad.

Look at the bright side. You now have incentive to try and disprove/prove any of the assumptions made by other writers and/or authors - just to see if you can make it work. The idea of having to have jump-1 drives for battle riders is something worth looking into. If you want to discuss drop tanks, you can wonder "why didn't they include drop tank designs for any of the Fighting Ships books ever put out (Both CT and MT). In the end, GDW gave us (the buyers) tools to shape and define our Traveller Universes to our hearts content. Whether we use the OTU background, or we design our own, doesn't really much matter. Just create your own designs (whether it is world design, fleet design, character design, or even historical background design) and have the pleasure of running it for your friends as the GM. Either that, or help your GM with some of the grunt work, and enjoy playing in his game universe.