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 The Trek BBS Warp Engine Efficiency Changes....

 Trek Tech Pass me the quantum flux regulator, will you?

 October 5 2013, 01:17 AM #1 Nob Akimoto Captain   Location: The People's Republic of Austin Warp Engine Efficiency Changes.... Continuing my foray into "volumetrics hell" is a bit of a thought experiment conducted using a very rough, spitballed idea of the change in efficiency per cubic meter of volume propelled at warp speed. First, this is rough and it's still sketching out ideas on how to play a bit with things like a ship's fuel efficiency, so note the numbers are going to change. So second, I decided to set a baseline. Working from as official a figure as I could find on fuel consumption, going with 6,000 m³ of fuel (3,000 m³ of deuterium/3,000 m³) for the Enterprise-D, I then worked backward to 3 years of warp 6 till fuel exhaustion to get an overall generation of 1121TW for 3 years. This is a tiny figure in the context of a starship's warp reactor. In terms of volume this works out to about 80cc of fuel per second using the canonical conversion rate of around 93%. Now, the assumption is that the mass of a starship in fact influences how much power is needed to drive it a certain warp factor. So taking the 1121 TW, I then divide it by the Enterprise-D's official mass of 4.5 million metric tons. This gives us a needed output of 635,000 watts per cochrane per ton. Put more simply it works out to about 250 MW per ton to sustain the 392.5 cochranes of Warp 6. I'm assuming for the moment that the energy required to cross a peak transitional threshold remains constant over the years as it's described as being some sort of subspace physics constant. Therefore we then move on to comparative masses. For the Constitution I'm going to go with the more canonical figure of closer to a million tons than the much lower 190,000 metric ton fandom figure. Excelsior and Intrepid I'm using the "official" figure of 2,350,000 tons and 700,000 tons. Overall this means to sustain 392.5c each of the ships require the following output: Galaxy - 1121TW Constitution - 211TW Excelsior - 585TW Intrepid - 175TW Then we divide these output figures by the amount of total internal volume each ship contains. This gives us: Galaxy - 5,171 m³/TW Constitution - 1,038 m³/TW Excelsior - 1,451 m³/TW Intrepid - 3,582 m³/TW Basically for every TW of output each of the ships can move the given amount of payload volume. Basically it's an engine/nacelle efficiency vs. the rest of the ship measure. At around the same mass, a 24th century starship can have a payload 3.5x as voluminous. Now, we can of course assume that advances in warp coils, etc. would actually reduce the power consumption per cochrane per ton, but this is still a rather interesting way to look at the technological advances from the 2260s to the 2380s.
 October 5 2013, 01:31 AM #2 Nob Akimoto Captain   Location: The People's Republic of Austin Re: Warp Engine Efficiency Changes.... As a side note, the Intrepid/Constitution contrast gives us a nice place to examine the relative usefulness of nacelle as part of hull volume. Specifically of the 210,000 m³ of volume available to a Constitution approximately 25% or 54,000 m³ is dedicated to warp nacelles. (The number is similar for the refit) For the 625,000 m³ Intrepid the ratio is much smaller. 17,000 m³ per nacelle, or 34,000 m³ total which is 5.5% of total volume. We do know that Voyager when landing seems to be much more "back" heavy in that the nacelles are capable of counteracting the weight of the primary hull. The density of the rear half of the ship then becomes at least 50%, and given the relative volume of the hulls, most of the extra mass is probably in the nacelles. If we assume uniform distribution of mass on the Constitution and something of a 15% mass of Voyager in her nacelles, (leaving something like a 50/35 split for her primary hull/secondary hull) we have comparative nacelle masses of: Constitution - 212,500 tons Intrepid - 105,000 tons So per ton of nacelle... Constitution - 4 total tons/ton of nacelle Intrepid - 6.67 total tons/ton of nacelle And...(Rounded to the nearest cubic meter) Constitution - 1 m³/ton of nacelle Intrepid - 6 m³/ton of nacelle And finally on a volume basis(Rounded to the nearest cubic meter): Constitution - 3 payload volume m³/m³ of nacelle Intrepid - 17 payload volume m³/m³ of nacelle
 October 12 2013, 12:16 AM #4 Nob Akimoto Captain   Location: The People's Republic of Austin Re: Warp Engine Efficiency Changes.... It'd probably help for me to post up my numbers. (It's rather sloppy that I didn't, and I apologize) My notes say that my assumed mass figure for ²H was 196.7 kg/m³. I can't for the life of me remember where that figure came from. I'll recalculate with standard deuterium densities, I think. I'm actually still debating on whether or not the effects of mass, volume and field geometery on warp propulsion. The thing that kind of troubles me about the power consumption figures in the TNGTM is that the implication throughout on warp drive is that fuel isn't the limiting factor for higher warp factors. This implies that it's coil components or hull stress that starts causing problems at super high warp factors. However, a comparison of the energy requirement chart vs. fuel capacity (even assuming high density slush deuterium at the nearly 200kg/m³ I erroneously had above) suggests that fuel capacity would become an issue significantly faster than supposed other factors would be. Warp 9.6 for can't be sustained for the 12 hour limit because fuel exhaustion would kick in at the 4 hour mark. Also the other problem is that the physical size of the warp core seems extraneous with the fuel figures we have. Even a reaction chamber of only 1 cubic meter would expend all 6,000 m³ of deuterium in an hour and a half at maximum throughput. (Noting that the reaction chamber is supposed at least 2.3 x 2.3 x 2.5m in dimensions, it's probably substantially larger than 1m³ in reaction volume). We also know that the Galaxy-class puts warp reactor output to 75% when they go into Red Alert. And that this readiness state protocols require procedures in case of duty shift changes. In which case we should probably assume the ship can sustain that level of output for multiple duty shifts (4 hr intervals, presumably). But again, even a minimally sized reactor would eat through its entire anti-deuterium supply in a bit over 2 hours at 75% output. Something's not right here. Need to figure out what it is. I'm going to be posting more of an in universe examination, that kind of glosses over the whole tonnage issue soon as a side bar in the procurement thread (I do think size and mass should have some impact on warp propulsion, but that there's probably something in the order of subspace field stress that can shake a ship apart (see: Defiant).
 October 14 2013, 01:48 AM #6 Nob Akimoto Captain   Location: The People's Republic of Austin Re: Warp Engine Efficiency Changes.... Specific thoughts on your observations maybe tomorrow. For now: Here's the post in question. http://www.trekbbs.com/showpost.php?...5&postcount=60
 October 17 2013, 06:39 AM #7 zDarby Lieutenant   Location: NorCal Re: Warp Engine Efficiency Changes.... @Akimoto -- I very much appreciated your warp nacelle post. I like it because it makes warp energy usage for Ent-D just one of the possible curves it *could* have been, and, indeed, what it was turned into. But it does beg the question if the four nacelle designed are an attempt to allow for enhanced change in warp geometry, allowing for better economy for any given warp factor... At the expense of considerable complexity.
 October 18 2013, 09:02 PM #8 Nob Akimoto Captain   Location: The People's Republic of Austin Re: Warp Engine Efficiency Changes.... http://www.trekbbs.com/showthread.ph...88#post8779888 Here's a stab at it, zDarby. Lemme know what you think.

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