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02-27-2020, 05:44 AM | #11 | |
Join Date: Nov 2018
Location: Live in Seoul, Korea and I have never been abroad.
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Re: [Spaceships] It seems that TL7 Chemical Rocket's acceleration is an overspec.
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02-27-2020, 05:50 AM | #12 | |
Join Date: Jul 2008
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Re: [Spaceships] It seems that TL7 Chemical Rocket's acceleration is an overspec.
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The easiest approach would probably be to keep track of remaining delta-V and use that when needed to calculate remaining fuel fraction, then remaining total mass, then maximum acceleration.
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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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02-27-2020, 07:01 AM | #13 | |
Join Date: May 2005
Location: Oz
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Re: [Spaceships] It seems that TL7 Chemical Rocket's acceleration is an overspec.
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That comes down to the F-1 burning kerosene and LOX, whereas the TL7 chemical rocket is probably based on a LOX-LH₂ upper stage or shuttle main engine with less thrust but better specific impulse, more suitable to operations in space.
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Decay is inherent in all composite things. Nod head. Get treat. |
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02-27-2020, 08:16 AM | #14 | |
Join Date: Feb 2006
Location: Not in your time zone:D
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Re: [Spaceships] It seems that TL7 Chemical Rocket's acceleration is an overspec.
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"Sanity is a bourgeois meme." Exegeek PS sorry I'm a Parthian shootist: shiftwork + out of country = not here when you are:/ It's all in the reflexes |
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02-27-2020, 10:09 AM | #15 |
Join Date: Feb 2005
Location: Berkeley, CA
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Re: [Spaceships] It seems that TL7 Chemical Rocket's acceleration is an overspec.
In general Spaceships is a tad generous with rocket performance, mostly because if you aren't generous it will be inordinately difficult to design something useful (in part because it really is inordinately difficult, in part because the design simplifications of Spaceships makes it even harder).
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02-27-2020, 11:13 AM | #16 | |
Join Date: Aug 2007
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Re: [Spaceships] It seems that TL7 Chemical Rocket's acceleration is an overspec.
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There's also no magic in any given number of Gs. The shuttle had to throttel back when it hit 3 Gs because of mechical limits of the vehicle. A Titan II second-stage carrying a Gemini capsule ended its' burn at just under 7 GS. So did an X-15 rocket plane. The msot important thing to remebr is that though Spaceships does give you a G number and a Delta-V figure that you can use in combat those things are mostly calculated on an average per mission basis not as second by second simulation. What does Spaceships do to simulate how your Gs of thrust go up as you burn fuel and/or how your fuel use goes down as mass decreases while holding a given aceleration? It averages your acceleration and fudges your Delta-V with that adjustment in the Fuel tank section for the number of tanks. Spaceships is a simple system, an abstact system and not a second by second simulation. Even Ve2 wasn't really and it was far more complex than Spaceships.
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02-27-2020, 11:28 AM | #17 |
Join Date: Feb 2016
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Re: [Spaceships] It seems that TL7 Chemical Rocket's acceleration is an overspec.
There is a reason why 'rocket science' is an analogy for something that is really, really hard. It is a highly complicated field that has to take into account four dimensional space-time, material sciences, aerodynamic drag, gravitational drag, etc.
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02-27-2020, 11:55 AM | #18 | |
Join Date: Jul 2008
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Re: [Spaceships] It seems that TL7 Chemical Rocket's acceleration is an overspec.
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The text of Spaceships indicates to me a really clear understanding of the breakpoints and other factors that make a 'mission average' acceleration a largely useless number. Furthermore, if that's what it was trying to do it would be obviously doing it wrong since the mission average mass obviously depends on the fuel fraction while the Spaceships' acceleration values do not. Deciding that key statistics will not be subject to frequent recalculation even if logic suggests maybe they 'should' is an understandable and familiar GURPS game design choice. It doesn't need to 'justified' as an ill-concieved 'abstraction' of things the game does not in any way treat as abstract.
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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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02-27-2020, 12:55 PM | #19 | |
Join Date: May 2005
Location: Oz
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Re: [Spaceships] It seems that TL7 Chemical Rocket's acceleration is an overspec.
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I've seen a couple of issues arise because of the choices of what engines to represent. In this case it seems that the figures are correct for a hydrogen-burning orbital engine, and so don't match a kerosene-burning launch engine (which might be represented as a sort of "high thrust" option). In a recent thread I found that the stats for the TL7 fission rocket match NERVA or Pewee (which reached test-firing prototype stage) but underestimate what was expected from DUMBO (which was cancelled because of a political decision).
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Decay is inherent in all composite things. Nod head. Get treat. Last edited by Agemegos; 02-28-2020 at 05:14 AM. |
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02-28-2020, 01:34 AM | #20 |
Join Date: Nov 2018
Location: Live in Seoul, Korea and I have never been abroad.
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Re: [Spaceships] It seems that TL7 Chemical Rocket's acceleration is an overspec.
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