New Fuel equation and TL

[Jak Nazryth]

In a couple of games I've played a character in the early 2000's, T-20 to be specific, and a couple more times in Mega Traveler long before that, the GM's in question had house rules that allowed "hydrogen slush" in specialized fuel tanks, along with improvements in jump drive "fuel mileage" allowed a 5% rule instead of the normal 10% rule for jump drives. I have toyed with the idea as have many others over the years on the various boards I've bounced in and out of. It's logical that with higher tech levels you get more out of less.
I know there are science oriented individuals on these boards that can show me an equation in no time flat that can prove how many more hydrogen atoms you can get as a slush/simi-solid state over the same volume of liquid. (On the T-20 boards over a decade ago I once saw a post from an electrical engineer that argued you could NEVER have a laser pistol with a clip in the grip, because there was simply enough room to stack enough electrons in any know medium to yield enough of a charge to power a laser to do any actual damage... and then posted his equation to prove it! :lol: )
Anyway, at what tech level would it be reasonable to begin dropping the 10% rule to a 5% rule? 15, 16? Lower or higher?
Right now I’m thinking at TL 16 designs a 5% is easily attainable but expensive alternate to normal tanks that are covered in the cost of the hull. The 5% tanks would cost X credits per ton. Then you would also spend more cash on an improved version of fuel processors to convert LH20 into simi-solid slush. I’m thinking 10x the cost over the normal fuel processors and 10k per ton of specialized fuel tanks. I have no basis on these prices, just a best uneducated guess. I know currently we have containment systems that can maintain incredibly cold environments, so why not advanced sci-fi tech?
Any thoughts

 

[F33D]

Metallic hydrogen is your best bet. ~12 times the density of LHyd. TL-12 should suffice...

 

[Captain Jonah]

The question is really down to what is the fuel used for and at what stage of the jump in your verse.

If you are required to use H in gas form and 95% of it is used in the first 30 seconds of the jump then you are stuck.

On the other hand if 50% of the gas is used on jump to create the jump bubble and the rest over the course of the jump then you can do it now (tech 8+) and reduce the Fuel volume to 60-70% (6-7% per jump number times ships size).

You can easily get something with 3-4 times the volume of H compared to H itself and cracking the easy stuff is, well, easy.

So if you decide that 50% of the fuel is used at jump initiation then you need to have that much gaseous H ready to go. Then in jump you crack the remainder as needed.

What ever you set the initial % to is the size of tanks you must have ready for instant use, the rest can be in slush tanks ready to be cracked.

So a scout with J2 would need a 10Dton Gaseous H tank and then a 2-4Dton slush tank for the remainder of the trip plus 2-4Dtons of slush for the power plant. You simply crack the slush as you go and fill the gas H tank for use by the Power plant and Jump drive. So a 100Dton scout could maintain exactly the same jump and power plant durations with a maximum of 18Dtons of tanks.

A far trader could have a 20Dton Gas H tank and a 8Dton slush tank for a total of 28Dtons of tanks for the same performance.

Go with the higher size of slush tanks to allow for having to use lower H slush in emergencies but you can still reduce the total fuel tankage of your ships by about a third or more.

 

[FallingPhoenix]

If you are required to use H in gas form and 95% of it is used in the first 30 seconds of the jump then you are stuck.

I think the Metal Hydride storage descriptions says something about regular storage being cryogenic liquid hydrogen, not gaseous and if a drop tank works to power your jump but be dropped off before you actually jump, it seems that it all has to be used right off the bat.

 

[alex_greene]

Remember: the 10% rule, like a lot of the tech rules, is something that's pulled out of the top of MWM's head.

If you wanted to, in your setting the fuel for the P-plant and M-drive could run it for 150 years, and you could decide that the fuel required equals 1/10 of the mass of the Jump-drive per Jump rating, rather than 1/10 of the mass of the ship.