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Post by RA2lover on Oct 15, 2016 13:38:23 GMT
At these masses, you might as well ditch the explosives and use the remote control as a kinetic payload.
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Post by RA2lover on Oct 15, 2016 13:18:32 GMT
Seems like it's all a matter of how much you are willing to heat the barrel.
Ignoring heat gradient losses, firing 1kg of octogen each second and assuming half of its energy goes towards heating the barrel instead of accelerating the projectile or escaping through muzzle blast, heating the barrel to 1000 K needs 50m² of radiator area. rise it to 2000 K, and you only need 3.15m², though i'm not sure how many shots the barrel can last at that temperature. Those temperatures would also require an open bolt to prevent ammunition cookoff.
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Post by RA2lover on Oct 15, 2016 12:41:21 GMT
Engines still lack TWR at small sizes due to turbopump mass efficiencies. You won't get good results from just 1.2cm worth of turbopump radius. Sorry. I'm still in a pirated 1.0 (still intending to buy the game once it goes on sale) so i can't benefit from the higher expansion ratios or smaller nozzle sizes you can have with the throat size reduction, but here's a much better design: It should save 61.3 grams in mass compared to your current layout, while providing twice the thrust. The missile will still lose about 50m/s due to a worse specific impulse(can't use a larger nozzle without hitting the 10cm size restriction), but i believe the additional thrust to mass ratio should work out better. BTW, you can also use a UHMWPE nozzle with this design to save an added 3 grams for double the cost. RCC also works, though has a worse improvement. BTW - your current missile has a wrong stoichiometric ratio for the fuel tanks, should be 950g:100g (3 grams off), or 1000g:110g(41.7 grams off, i'm assuming 0.1 OoM steps).
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Post by RA2lover on Oct 15, 2016 0:57:35 GMT
The files are readable - they just have an inconsistent format as some of them use CRLF(which notepad parses as a new line) and others use just LF(which notepad doesn't parse as a newline).
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Post by RA2lover on Oct 14, 2016 22:08:22 GMT
...
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Post by RA2lover on Oct 14, 2016 16:43:41 GMT
I've ignored the plane change and directly went for a elliptical flyby instead.
You really don't have much of a window to attack with the default ships while taking that option, though - the approach speed in that scenario is over 25km/s, and i've had better results with a large manually detonated flak missile instead.
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Post by RA2lover on Oct 14, 2016 4:16:12 GMT
I'm more interested in subcritical reactors instead.
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Post by RA2lover on Oct 14, 2016 3:13:05 GMT
Tritium wouldn't be efficient mass-wise because of the sheer amount of radiators you would need.
at a 16 K exit temperature(which you'd need to keep the current efficiency), you'd need 138594 m² of radiator area. Even at 21 K that's still 46704 m². At this point using a heat pump could actually significantly reduce radiator area, but i haven't done the math on what efficiency figures you'd get out of that and whether it's viable.
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Post by RA2lover on Oct 14, 2016 2:40:38 GMT
You don't need that high of an exhaust temperature when emitting this little heat. You can dissipate 11.8kW with 0.02m² of radiator area(the smallest radiator possible) at 1800K, 9.4kW at 1700 K, 7.25kW at 1600K, 5.7kW at 1500K, 4.3kW at 1400 K, 3.2kW at 1300 K, 2.3kW at 1200 K, 1.6kW at 1100 K and 1.1kW at 1000 K.
Your 2400 K output temperature allows you to dissipate a whooping 37.5kW with a single one of those radiator panels. I'd suggest reducing it to improve efficiency.
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Post by RA2lover on Oct 13, 2016 19:59:13 GMT
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Post by RA2lover on Oct 13, 2016 19:03:10 GMT
Here's a new contender for cheapest reactor that is also lighter than all others i have seen so far: (not pictured: 1cm 1RPM hydrogen/lithium external coolant pump) You can get it to output more energy by increasing neutron flux and cooling, though i prefer the lower radiation output instead. Oddly, switching to a boron/boron nitride/boron carbide material for control rods reduces the reactor's mass by 0.02kg, though i don't know why exactly this happens.
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Post by RA2lover on Oct 13, 2016 14:44:52 GMT
My guess is less mass is being used on surface tension pumps/slosh baffles, though i'm not sure myself either.
Another possibility is limiting tank radius reduces the amount of force the walls need to resist against, though my hunch is it wouldn't work very well when you take the (lack of) fluid compressibility into account.
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Post by RA2lover on Oct 13, 2016 14:40:53 GMT
I actually think cannons fire too slowly, though i guess that's due to breech size being automatically picked and having the same material as the barrel.
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Post by RA2lover on Oct 13, 2016 3:23:13 GMT
Here's the lightest "efficient" thermocouple i can build so far: Sadly, it still needs about 25m² of maximum theoretical efficiency radiators. Even increasing the exit temperature to 510 K (and using silver as a heat conductor so you actually manage to have a reasonable length), that's still 15 m² worth of radiators. We need RTG fuel quantities smaller than 1kg to make them viable cost-wise:( As for a heavier alternative with a saner exit temperature, there's this: It fails miserably in terms of mass efficiency because both thermopile materials are (relatively to the amount of heat available) good heat conductors and need that much surface area to achieve the intended temperature delta. Here's a less efficient version that takes advantage of the low thermal conductivity of uranous oxide to work, and manages to get a higher operating temperature: If you don't care about cost, RTGs still perform better mass-wise at very low power usage. Sorry.
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Post by RA2lover on Oct 13, 2016 1:47:48 GMT
This assumes thermal expansion coefficients have been fixed. Some thermocouple materials currently aren't usable due to incorrect thermal expansion values, and haven't been included on this list for now.
All values were empirically obtained on the ingame RTG designer, and might be off by about 1~2% on materials with high temperature deltas.
Aluminum: 13 K Bismuth: 224 K Cadmium: 42 K Copper: 16 K Gold: 185 K Iron: 20 K Lead: 13 K Molybdenum: 347 K Nickel: 130 K Platinum: 125 K Silver: 34 K Tantalum: 132 533 K Tungsten: 510 K
Amorphous Carbon: 148 K Diamond: 1456 K Graphite: 2361 K Pyrolytic Carbon: 1040 K Selenium: 810 K Silicon: 225 K
Sodium: 13 K
Constantan: 30 K Nickel Chromium Cobalt: 251 K Nickel Chromium Iron: 746 K Platinum Molybdenum: 99 K Tungstenium Rhenium: 310 K
Uranium Dioxides: 75 K
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