[Spaceships] Perpetual Motion? - Page 3

acrosome · 10-27-2015, 04:26 AM

The Chemical Refinery (SS1 p.19) requires one power point and produces rocket fuel (e.g. 0.5 tons/hour at SM+5). This is specified as LOX and H2.

The Fuel Cell (SS1 p.20) runs on rocket fuel and produces one power point for an arbitrary amount of time, which is 3 hours at TL7 on integral tankage

A Fuel Tank (SS1 p.17) of rocket fuel will power a fuel cell for 4x as long as integral tankage, strongly implying that the integral tankage is 1/4 of whatever a system mass is (e.g. 1/4 of 5 tons at SM+5 is 1.25 tons).

Since the TL7 Fuel Cell runs for 3 hours on 1.25 tons of rocket fuel, it consumes 0.4167 tons of rocket fuel per hour. If it powers the refinery this makes 0.5 tons of rocket fuel per hour. Thus, this combination can produce a net 0.0833 tons of rocket fuel per hour forever.

It's even worse at higher TLs and larger systems. At TL10+ for SM+5 it's a net 0.495 tons/hour. I'm thinking that Chemical refinery production should be divided by 10- that would be just enough to keep from breaking even.

Errata? Or just a rounding error/below granularity?

Also, since the chemical refinery makes rocket fuel, is there a rule to divide production by 9 if you're only keeping the hydrogen? This seems reasonable- an oxygen molecule is mass 32, and two hydrogen molecules are mass 4, so the mass fraction is 4/36 = 1/9.

Another question: For rockets that have the option of using water as reaction mass- can one switch between water and hydrogen at will, or must the rockets and tankage be fuel-specific? Clearly in the Real World it is the latter, but I don't see how making a multifuel rocket would be beyond the capabilities of a society that can make a ram-rocket. Perhaps double cost (since a ram-rocket is 5x cost)? There are also rules for other reactions masses, like ammonia; same question.

Related question: Clearly, one uses the Chemical refinery to crack water into LOX/H2 or to make hydrogen. I assume that one can specify a version that isolates ammonia or methane as well. But what about water? It only costs $20/ton, but I assume that's at the starport and is mostly infrastructure and handing costs. So if you have to do a true frontier refuel someplace that liquid water is available can I assume that one can just filter it and pump it into the tanks, and that any ship capable of using water will have such a filter/pump? If so, what is a fair pumping rate? One fuel tank per hour? Is it different if the water is ice?

Final question: Are there stats for what one power point is, somewhere?

10-27-2015, 04:26 AM	#1
acrosome Join Date: Aug 2010 Location: The Land of Enchantment	[Spaceships] Perpetual Motion? The Chemical Refinery (SS1 p.19) requires one power point and produces rocket fuel (e.g. 0.5 tons/hour at SM+5). This is specified as LOX and H2. The Fuel Cell (SS1 p.20) runs on rocket fuel and produces one power point for an arbitrary amount of time, which is 3 hours at TL7 on integral tankage A Fuel Tank (SS1 p.17) of rocket fuel will power a fuel cell for 4x as long as integral tankage, strongly implying that the integral tankage is 1/4 of whatever a system mass is (e.g. 1/4 of 5 tons at SM+5 is 1.25 tons). Since the TL7 Fuel Cell runs for 3 hours on 1.25 tons of rocket fuel, it consumes 0.4167 tons of rocket fuel per hour. If it powers the refinery this makes 0.5 tons of rocket fuel per hour. Thus, this combination can produce a net 0.0833 tons of rocket fuel per hour forever. It's even worse at higher TLs and larger systems. At TL10+ for SM+5 it's a net 0.495 tons/hour. I'm thinking that Chemical refinery production should be divided by 10- that would be just enough to keep from breaking even. Errata? Or just a rounding error/below granularity? Also, since the chemical refinery makes rocket fuel, is there a rule to divide production by 9 if you're only keeping the hydrogen? This seems reasonable- an oxygen molecule is mass 32, and two hydrogen molecules are mass 4, so the mass fraction is 4/36 = 1/9. Another question: For rockets that have the option of using water as reaction mass- can one switch between water and hydrogen at will, or must the rockets and tankage be fuel-specific? Clearly in the Real World it is the latter, but I don't see how making a multifuel rocket would be beyond the capabilities of a society that can make a ram-rocket. Perhaps double cost (since a ram-rocket is 5x cost)? There are also rules for other reactions masses, like ammonia; same question. Related question: Clearly, one uses the Chemical refinery to crack water into LOX/H2 or to make hydrogen. I assume that one can specify a version that isolates ammonia or methane as well. But what about water? It only costs $20/ton, but I assume that's at the starport and is mostly infrastructure and handing costs. So if you have to do a true frontier refuel someplace that liquid water is available can I assume that one can just filter it and pump it into the tanks, and that any ship capable of using water will have such a filter/pump? If so, what is a fair pumping rate? One fuel tank per hour? Is it different if the water is ice? Final question: Are there stats for what one power point is, somewhere? Last edited by acrosome; 10-27-2015 at 05:07 AM.