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Post by nerd1000 on May 26, 2017 14:14:21 GMT
Project Rho has a similar calculation for beer, which gives a exhaust velocity of 83m/s and thrust around 84N.
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Post by nerd1000 on May 26, 2017 4:04:30 GMT
( COADE assumes that everything is built using perfect molecular manufacturing methods, though it ignores many other implications of that tech: bulk materials are weak because they have tiny cracks or steps in them that concentrate stress at their tips and propagate through the material to cause breakage if the stress becomes great enough. Our materials should be far stronger if they're assembled so perfectly) Does it really? I've never seen qswitched explicitly state this (whether through the game's infolinks or on the blog), or even imply it as strongly as everyone seems to think. Material prices are grounded on solar abundance of the elements, but I think the idea there was to make the minimal number of assumptions about a space-based economy. Just totalling up how much stuff there is in Sol and not being concerned with how it is acquired or machined or anything. The game's economic model, such as it is, arguably answers too few questions, leading to wild mass guessing about how the middle steps of collection, processing and manufacturing work from the flawless performance of overoptimal module designs. Many of the things we make in-game (like diamond exhaust nozzles, amorphous carbon turbopump impellers or gigantic laser rods) are basically impossible to build without molecular manufacturing.
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Post by nerd1000 on May 25, 2017 8:02:56 GMT
No reason we can't have a modded category. That said, our friend at RFPOCA orbital command may be a little unhappy about the 'poorly understood' materials.
Also, it's natural (ha ha) for this kind of ship to 'suck' by normal COADE standards. 99.3% of the fuel in your reactor is useless U-238, so you'll never achieve the performance levels possible with highly enriched fuel. Thankfully you're building a civilian ship that doesn't need to fight or accelerate hard, so we can get away with crap performance. Also the game appears to have something odd going on with the calculations of the reactor's neutron economy: observe my main reactor, apophys's main reactor and apophys's NTR: They've all got a resonance escape probability of 0, indicating that all of the neutrons are being absorbed by the U-238. U-238 is not fissile, so this sort of thing should probably result in a reactor that doesn't work...
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Post by nerd1000 on May 24, 2017 8:31:22 GMT
For railguns the main limitation is the rail erosion problem. I doubt that many of COADE's railguns could fire more than 100 shots before failure IRL. COADE also glosses over a lot of engineering constraints and issues seen in real life. It doesn't model weakening due to heat, materials fatigue, the EMP produced when the railgun fires, the wires you need to conduct the absurd current flowing through your rails, manufacturing constraints (COADE assumes that everything is built using perfect molecular manufacturing methods, though it ignores many other implications of that tech: bulk materials are weak because they have tiny cracks or steps in them that concentrate stress at their tips and propagate through the material to cause breakage if the stress becomes great enough. Our materials should be far stronger if they're assembled so perfectly), the sheer difficulty of producing some materials that are very cheap in-game, et cetera et cetera.
Also our guns weigh somewhere between 60 kilos and 1000 tonnes, yet they fire projectiles that are smaller and lighter than a standard assault rifle bullet. In atmosphere such projectiles would very quickly be stopped or melted by the air, and they'd be very inaccurate even over their short ranges because there's nothing to stop them from tumbling. You can get a longer effective range and more damage from a conventional cannon of the same mass. The US Navy's railgun project is attempting to fire something the size of a regular artillery shell, with a sabot and fin stabilization to allow accuracy over great ranges. Try building a railgun that fires a 8 kg bullet at useful speed in-game and you'll start to see the problem.
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Post by nerd1000 on May 24, 2017 5:38:05 GMT
And here's my reference entry.
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Post by nerd1000 on May 24, 2017 3:59:42 GMT
Your reactor and NTR must have low enough radiation levels for manual servicing (they must not exceed radiation limits on an aluminium crew capsule placed directly above them without any radiation shield). Differently shaped crew modules have different radiation tolerance (presumably because radiation effects are counted at the center of the module). You could standardize to a one-man aluminum crew capsule, which has only one shape. done
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Post by nerd1000 on May 24, 2017 2:52:45 GMT
Republic of the Free Peoples Orbital Commerce Authority (RFPOCA) Design Memo N-00K-M3:
While many of our colonies have easy access to natural uranium ores, the RFP Navy is using up all our fissiles enrichment capability making weapons-grade uranium, presumably so that they can nuke the USTA's ashes a few more times just to be sure. This is a big problem for our normal interplanetary shipping concerns, and if something doesn't change soon we'll have a major supply crisis across the entire system. That's where you come in: We want you to investigate the possibility of re-equipping our ships with reactors and NTRs that can run on unenriched fuel. We require a power reactor of at least 1 MW capacity and a methane NTR of at least 500 kN thrust, gimbal range at least 8 degrees and a nozzle expansion ratio of at least 100. Tenders must include an example ship configuration, either tanker, freighter or cargo liner (combined freight and passenger) capable of finishing the standard 'Homecoming' orbital transport scenario.
Addendum: Notice from RFPOCA orbital command. I'll keep this brief. As I understand it, some of you eggheads have spent the last few months working for those nutjobs in the Navy. Things work a little differently around here: Maybe in the Navy you could get away with running a reactor 1K below meltdown or using a lithium pump coated in a thin layer of PTFE to move water, but unlike those Naval maddogs my crews have a sense of self-preservation, and unlike the Navy we don't execute them for refusing to fly a ship that's best described as suicidal. So when you're working on your tender, keep those facts in mind. We want our components made from well understood materials, operated within nice big safety margins, and we want to be able to fix them if they go wrong. Good luck.
Challenge rules: Design the specified reactor and NTR, then complete Homecoming using a ship built around them. Reactor and NTR fuel must be U-235 Dioxide with minimum enrichment level (0.720%). Components other than the NTR core must have a 10% margin of safety on melting point. Your reactor and NTR must have low enough radiation levels for manual servicing (they must not exceed radiation limits on a 1 man aluminium crew capsule placed directly above them without any radiation shield). No highly reactive material combinations (Fluorine reactor coolant is right out).
Scoring. Modules: Mass per Watt and cost per Watt for reactor, TWR, cost per Newton of thrust and exhaust velocity for the NTR. Ship: Cost per payload mass delivered to the station at the end of Homecoming. Payload may be a cargo bay, fuel, a passenger module (To avoid penalizing passenger ships I'll count the mass of the whole module, not just the passengers in it) or some combination thereof.
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Post by nerd1000 on May 22, 2017 5:49:02 GMT
*forces Martian to walk around in 1g until he keels over* Ahh, I was wondering what would break first! Your mind, or your body? >As if any Martian worth his iron would travel to such a disease rattled planet without his bio-mated exoskin, which i remind you is suited for up the 3g. But then again this was the same planet that had "Humans" who were so "smart" that they collectively decided to use the rain forest as a crop zone. Perhaps they should stick to something at their mental level, like putting an egg in a bucket. You Martian weaklings with your closed controlled environments. Do you even have an immune system anymore? I guess not, because if you did all your children would be dying of food allergies. Also the environment would be a hell of a lot better if your grandparents hadn't used hydrocarbon burning chemical boosters made from carbon fiber to get themselves (and their lifetime supply of tater-tots) out of our atmosphere .
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Post by nerd1000 on May 21, 2017 11:46:16 GMT
Another typical Terran with their soul held down by gravity! I bet you are mad because you don't have anymore irreplaceable biological species to accidentally wipe out or eat to death! The British Empire wined about all the resources when the Americans rebelled, and guess what the British empire was wrong and tyrannical and so is the Earthgov! Stay on Earth that little mud ball of a planet is doomed anyways! Oh, you think the gravity is your ally, you merely adopted the gravity. I was born in it, molded by it. I didn’t see zero-G until I was already a man; by then, it was nothing to me but disorienting! *forces Martian to walk around in 1g until he keels over* Ahh, I was wondering what would break first! Your mind, or your body?
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Post by nerd1000 on May 19, 2017 0:13:42 GMT
remington Shinda chikyū no kodomo-tachi Game is based on anime and supports shotguns. There are only 19 stock designs. (sorry, you haven't made enough posts for me to get a good idea of what you're about). That's basically my essence(especially the anime), I have no idea where I made any references to shotguns or the number 19 though. I really should post here more. Remington is an American firearms manufacturer well known for making pump-action shotguns. And at the time of my reply your post count was 19.
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Post by nerd1000 on May 18, 2017 5:44:25 GMT
remington
Shinda chikyū no kodomo-tachi
Game is based on anime and supports shotguns. There are only 19 stock designs.
(sorry, you haven't made enough posts for me to get a good idea of what you're about).
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Post by nerd1000 on May 18, 2017 1:48:29 GMT
This time I spent more than 5 minutes cobbling something together, with larger safety margins and dimensions for good measure. The Tower of Babel.62,330 Passengers to LEO @ 29,040¢ a seat, including 4kt of cargo. Also, Pttg my last submission carries 2kt of cargo, but you only marked it as 1kt; Dammit, I've been usurped! *shakes fist*
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Post by nerd1000 on May 16, 2017 12:16:59 GMT
Here's an idea. After your engine burn, don't let the reactor cool down. Instead just throttle it to maintain operating temperature- this won't use much of your uranium, because the reactor has no radiators or coolant flowing through it. With the inside of the reactor at vacuum, the soot deposits will start to sublimate away. In case any larger bits flake off, before the next burn just flush the reactor core out with a shot of inert gas. I call this the 'self cleaning oven' approach to NTR decoking.
Patent pending, all rights reserved.
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Post by nerd1000 on May 14, 2017 11:41:47 GMT
I think there is a relative consensus on this forum that methane (and the higher hydrocarbons) are basically the best NTR propellants, with a good mix of density and exhaust velocity. However, IRL, there is a significant problem with using hydrocarbons in a sufficiently-hot NTR: The thermal decompositions of hydrocarbons produces solid carbon, which can clog up the internal plumbing of the NTR. Thus my question is, is there any way of preventing that coking, besides running the NTR cold enough that the hydrocarbons do not decompose? The solution is simple: Don't use hydrocarbons as propellant in a NTR . If you really must use hydrocarbons: Run the NTR for a short enough time that coking isn't a major issue, add something to the propellant stream that reacts with carbon to form a gas or run the NTR so hot that the carbon deposits become vapour (It'll have to be a liquid or gas core NTR).
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Post by nerd1000 on May 12, 2017 10:16:43 GMT
Here's something interesting: en.wikipedia.org/wiki/Gas_dynamic_laserI think it would be quite straightforward to replace the combustion chamber with a high temperature nuclear reactor. After lasing the hot gas could be cooled in a heat exchanger and returned to the core, allowing the laser to operate indefinitely.
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