icekatze wrote:hi hi
I would be curious to know what sort of parameters the designers of Umiak warships use to determine their various weight ratios. I'm assuming that fuel tanks need to be armored in hopes of preventing the same fate that the Winter Tide faced, which would probably also prevent them from being able to just strap on extra tanks on an exposed girder.
I'm also now curious to know what the cost of building the space shuttle is, minus labor and bureaucracy, to see how the components costs compare to the fuel costs, but I can't find anything.
I think the fuel mass ratio you choose for a ship is based on how long the unit needs to operate between refuelings to be effective; a scout will have a much higher fuel ratio than a battleship. My estimate is that a combat vessel needs 100 hours of full-burn acceleration to be effective. Fuel consumption is not determined by how far you go, but by how hard you work at it. A warship in combat might burn up 100 hours of fuel in less than a week, while a scout might make the same 100 hours last for many months (because it isn't constantly under acceleration).
The space shuttle may not be a good analogue; on the one hand, fuel accounts for 90% of its mass... but on the other, it's just liquid hydrogen and oxygen, which is comparatively inexpensive (ignoring for a moment the solid rocket boosters).
In naval vessels, the difference between deadweight (empty) mass and full-loaded mass tends to be 15% for WWII-era battleships & heavy cruisers, 20% for modern warships, and 30% for WWII-era destroyers. This mass also includes ammunition and supplies, but I'm guessing that the vast majority of it is fuel. So for the comparatively heavy Outsider starships, my estimate is that fuel accounts for no more than 15% of the total mass of the ship; this is sufficient (within a reasonable engine efficiency) to allow a cruiser to accelerate at 30
g for the required 100 hours. Umiak have more efficient engines, but their ships are heavier, so their endurance is longer but probably in the same ballpark.
I'm not sure that the cost of the fuel is terribly relevant (unless it's exceptionally rare and expensive) to how much you carry; the designer sets a limit on the carrying capacity of the ship based on performance attributes, and in practice you carry as much as you can. Torpedoes are also very expensive, but that doesn't stop the Umiak from using a lot of them.
Antimatter is going to be incredibly expensive to produce, so its use is probably reserved for certain types of weapons. The idea behind the Taimat fuel is that it's not only easier to store than antimatter, but also cheaper to produce; presumably there is some process that you can put normal matter through that converts it into the excited state that allows for spontaneous annihilation. This might be something akin to an industrial-scale supercollider, or something as mundane as a catalytic reaction. It still requires significant infrastructure and energy to produce, and must be carefully stored and protected (it must be kept supercooled), but it shoudn't be prohibitively expensive.