08-27-2015, 11:52 AM | #61 |
Join Date: Oct 2004
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Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
Because the rules using sensors to detect it can be construed, as in post #12 in this thread, to make it not actually very stealthy at all. You'll note I posted after that. But whatever.
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08-27-2015, 11:56 AM | #62 |
Join Date: Feb 2005
Location: Berkeley, CA
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Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
Those rules are just a function of space being really empty. Terrestrial stealth technology, on a surface that's perfectly flat, has no cover, and is almost completely featureless, also does not work very well.
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08-27-2015, 11:58 AM | #63 | ||
Join Date: Oct 2004
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Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
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"Assuming your heat sinks are magical, you can suppress your IR output by quite a lot. The problem is that any realistic heat sink will fail in a very short time scale if used to keep your hull cool." |
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08-27-2015, 12:26 PM | #64 | |
Join Date: Jun 2013
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Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
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While on this tangent, I'd say that reaction drives with internal reactors (that is, all the ones that require main radiators) are probably at around -1 to detect with the main radiators closed. They last as long as a reactor with an IR signature 2 steps lower - that is, an NTR would be detected at +5 (normally +6) and would operate for 70 minutes (or an hour) with the main radiators closed. Last edited by Varyon; 08-27-2015 at 12:40 PM. |
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08-27-2015, 01:19 PM | #65 | |
Join Date: Jul 2008
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Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
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I don't know any 3e, so there is no chance that I am talking about 3e rules by accident. |
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08-28-2015, 03:25 AM | #66 | |
Join Date: Dec 2006
Location: Eindhoven, the Netherlands
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Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
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Of course, when you mention "heat sinks" that makes me think of reactors more powerful than the fuel cells that are your default form of power generation for a typical stealth hull (due to the limitation it has on a maximum IR signature). How would people feel about a heat sink reducing the IR signature of a ship?
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My Blog: Mailanka's Musing. Currently Playing: Psi-Wars, a step-by-step exploration of building your own Space Opera setting, inspired by Star Wars. Last edited by Mailanka; 08-28-2015 at 03:43 AM. |
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08-28-2015, 07:40 AM | #67 | |
Join Date: Jun 2013
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Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
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Spaceships doesn't currently have a system for dumping the heat that is built up while the main radiators are closed (presumably, it's meant to be something like "once you open the radiators again, all built up heat is gone," but that doesn't seem realistic). I'd have the radiators be able to handle dumping more heat than the systems normally generate, allowing them to shed built-up heat while the system is still in operation. If a system was filled to capacity, it would take 30 minutes to dump it in this way. If the system is shut down, the radiators can dump heat in half the time. While dumping heat, the vessel is at +2 to IR or a total of +6, whichever is higher (if the systems are shut down, it's at +6 total to detect if dumping at a normal rate, +8 total if dumping at twice normal). So, let's say we've got a ship with a fusion reactor (+7 IR). If we want to drop this to +3 by closing off the main radiators, it will last for 20 minutes, +20 minutes per full tank of coolant. If the ship has 4 tanks full of coolant, it can stay in stealth mode for up to 100 minutes. At the end of this time, the ship shuts down its reactor and starts dumping heat as fast as possible. It will take 50 minutes to fully flush the system, and it will be at +8 IR during this time. If it instead opted to flush the system while the reactor was active, it would take 100 minutes and leave the vessel at +9 IR. As for the sort of "heat sink" you're talking about (and that I originally started posting about, before looking it up and finding out a heat sink isn't what I thought it was), a tank of coolant will serve best there. I'd love a more in-depth system for those, but we don't have one currently. The coolant should last an amount of time based on the IR signature of the system(s) being cooled, as well as number of systems. As a first concept, I'd be tempted to say that coolant should be able to cool a single +6 IR system for an hour. Every +1 to IR signature would be -1 SSR to time, every -1 would be +1. Dumping heat would probably follow the above, although with the coolant normally taking an hour to fill it should take an hour to dump (or 30 minutes if dumping it while nothing else is active). For multiple systems, use the average time and divide by the number of systems. For example, take a vessel with 2 fusion reactors, a fuel cell, and a fusion torch. The reactors are each +7 IR (0.7 hours each), the fuel cell is +4 IR (2 hours), and the fusion torch has an internal footprint of +8 IR (0.5 hours). The average is about 1 hour, so divided by 4 systems that works out to 15 minutes per tank of coolant. Superscience coolant should last longer (potentially a lot longer - a cosmic power plant would fill a tank of normal coolant in all of 6 minutes). |
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08-28-2015, 07:52 AM | #68 | |
Join Date: Dec 2006
Location: Eindhoven, the Netherlands
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Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
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So, you argue that the IR signature comes from the radiators, which makes sense. The rules discussing retracting your radiators seems to be discussing them from the perspective of avoiding damage. If I read you correctly, though, it would also lower your IR signature, because the reason we have radiators is that ships don't radiate IR energy well enough on their own. Thus, for a spooky, super-science, radiator-less ship, the ship radiates heat well enough without an exposed radiator, but you make the case that it could, instead, choose to dump its heat into a coolant system, reducing the IR signature to, say, +3 for 30 minutes, after which the system starts to overheat (Super science can, of course, mean anything, but if the only assumption we make is "no exposed radiators" does this pass the smell test?)
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My Blog: Mailanka's Musing. Currently Playing: Psi-Wars, a step-by-step exploration of building your own Space Opera setting, inspired by Star Wars. |
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08-28-2015, 08:07 AM | #69 | |
Join Date: Jun 2013
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Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
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08-28-2015, 08:16 AM | #70 | |
Join Date: Dec 2006
Location: Eindhoven, the Netherlands
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Re: [Spaceships] Heat Signature, Cloaking Device, and Stealth Hull
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My Blog: Mailanka's Musing. Currently Playing: Psi-Wars, a step-by-step exploration of building your own Space Opera setting, inspired by Star Wars. |
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Tags |
cloaking device, detection, heat signature, spaceships, stealth hull |
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