[Spaceships] multi-fuel fuel tanks?

[AlexanderHowl]

All liquid rockets can increase thrust and lower delta-v without any issues by varying mass flow (cold mass mixing with hot mass increases thrust while proportionally decreasing delta-v). Delta-v is implicitly set at maximum levels and, as mentioned before, increasing delta-v without improving the underlying technology is a bad idea. At best, you end up with a damaged engine. At worst, an explosion that destroys your ship (and, with volatile systems, possibly nearby ships).

In the case of a spaceship trying to operate at higher delta-v than designed, I would require an Engineering roll and a HT roll at -1 per 10% increase. The Engineering roll determines if you are doing it right while the HT roll determines that the spaceship can handle it. For the Engineering roll, a success allows for enhanced operations for an hour at the enhanced setting while a failure means normal operations. For the HT roll, a success means that the system is disabled after an hour while a failure means that the system is destroyed after an hour.

[the-red-scare]

Originally Posted by Say, it isn't that bad!

The "t" spec for a fuel tank might be regarded as an abstract unit, if you're looking into more realistic fuel systems.

*Certainly, one cubic metre of liquid hydrogen, does not weigh the same as one cubic metre of Orion drive bombs.

* Since I haven't actually looked this up, in the unlikely event the weights are equivalent, I guess I'll just shrug and move on. :)

Spaceships fuel tanks, like everything else, are rated for mass and explicitly ignore volume. So a ton is a ton.

[Say, it isn't that bad!]

Originally Posted by the-red-scare

Spaceships fuel tanks, like everything else, are rated for mass and explicitly ignore volume. So a ton is a ton.

Alright, fair enough.

[thrash]

Originally Posted by Anthony

I would also point out that the rules for varying thrust and performance by fuel type are really just maximums for thermal rockets; you can increase thrust by just increasing the amount of reaction mass you're feeding into the system ...

So you'd be okay with a (non-superscience) TL10 fusion rocket that produces 0.5g at 0.6 mps, rather than the rated 0.005g at 60 mps? I've been doing something similar for my own purposes, but always thought I was straying into limited super-science.

[Anthony]

Originally Posted by thrash

So you'd be okay with a (non-superscience) TL10 fusion rocket that produces 0.5g at 0.6 mps, rather than the rated 0.005g at 60 mps?

A fusion rocket isn't thermal, but that's not a ridiculous upgrade on a nuclear-thermal rocket for going from TL 9 to 10.

[Say, it isn't that bad!]

Originally Posted by Anthony

A fusion rocket isn't thermal, but that's not a ridiculous upgrade on a nuclear-thermal rocket for going from TL 9 to 10.

Could you unpack how "isn't thermal" works in this case? I think I know what you mean, but I'm not sure, and I'm muddy on the details. Partly because fusion is a very hot process. Not counting some superscience "cold fusion".

[AlexanderHowl]

As long as the engine does not exceed the performance of an HEDM rocket, it is probably realistic. You could have a fusion rocket doing 2g and 0.5 mps per tank, it would have pretty much the same profile (it is cheaper to do high thrust systems than high delta-v systems because high thrust systems use open-cycle cooling).

In fact, that would be a realistic variable system at TL9. Low gear would have the fusion rocket doing 2g/0.5 mps, middle gear would be 0.1g/3 mps, and high gear would be 0.005g/12 mps. It would give a really good reason for people to adopt fusion rockets.

[Anthony]

Originally Posted by Say, it isn't that bad!

Could you unpack how "isn't thermal" works in this case?

Well, I guess it might be thermal depending on the design (unclear as written), but the key point is that it's not using a physical nozzle, and that puts a different set of limits than what you get for a physical nozzle.

[Say, it isn't that bad!]

Originally Posted by Anthony

Well, I guess it might be thermal depending on the design (unclear as written), but the key point is that it's not using a physical nozzle, and that puts a different set of limits than what you get for a physical nozzle.

Alright, thanks. Can see how a magnetic nozzle has some definite requirements and limitations, as opposed to a physical one.

[acrosome]

Hmm. All a great discussion. Where are the rules for Reconfigurable Systems?