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Old 01-19-2011, 03:47 AM   #4
vicky_molokh
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Default Re: [Spaceships] Non-TL^ Power Plants and air propulsion below TL7?

Quote:
Originally Posted by munin View Post
A TL5 Steam Engine (p. HT14) requires 250 lbs./hr. of wood and 400 lbs./hr. of water (and some amount of oxidizer without access to an atmosphere) for an 8,000-lb. engine. That implies that a Fuel Tank system would run a Steam Engine system for no more than 12 hours (depending on how much mass of oxidizer is required).

A TL6 Internal Combustion Engine (p. HT14) requires 8/3 lbs./hr. (and again, some amount of oxidizer) for a 125-lb. engine, so a Fuel Tank system would run an ICE system for no more than 48 hours.

How much oxidizer do we need? I'm going to guess a 3:1 ratio of oxidizer to combustible by mass*. That gives us 3 hours per Fuel Tank of wood† for a TL5 Steam Engine system, and 12 hours per Fuel Tank of gasoline for a TL6 ICE system. As a reality check, the TL9 MHD Turbine (p. SS20) provides two power points for 24 hours on a Fuel Tank (comparable to one power point for 48 hours), so we're not busting any TL barriers here. If I've mis-estimated the amount of oxidizer required, use a different divisor.

I don't know if the idea (or at least the production) of an oxidizer is appropriate pre-TL7 though. That might be why these aren't listed.
Oxydizer doesn't enter the equation yet.

Hmm. ICE's 12 hours per Fuel Tank (which seems to imply 3 hours for Internal Fuel) seems quite good. In fact, it matches the rate of the Fuel Cell from TL7. Why is it TL7 then?
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