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Post by Durandal on Oct 3, 2016 12:59:50 GMT
Guys, guys, guys...why must you post beautiful these things before I have to go to work?  Any tips on developing engines like these? Trial and error or do you all have a method that you follow? (Somebody slap some of these new engines on a Gt-nuke and post the results.) Has anyone tried one of their super ships out in sandbox? I built a clunky, mostly immobile tungston giga-tube last night that can just sit there and tank fire from several ships for a good while. I'd imagine a few centimeters of diamond is much more effecient than a few meters of tungstun. ;p |
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Post by RA2lover on Oct 3, 2016 18:13:37 GMT
Regarding NTR design, the heaviest component is probably the pump - you want your reactor to produce as much heat as possible as this is what defines how much thrust you can make out of the reactor. The easiest way of doing this without increasing reactor mass is increasing neutron flux to as high as you can before htiting the 6 month runtime barrier. After that, the pump needs to be made as light as possible. Liithium is probably the best pump material if only because of its low density, though it limits you to a maximum pump size due to structural stress. The next tier up is probably boron and that's about 3x as dense.
After optimizing the pump to be as light as possible for a mass flow rate that is just enough to prevent the reactor from melting down, you can optiimize the chamber to improve your thrust and specific impulse figures while not cracking itself. Boron is a pretty good starting material for that, though it's limited due to its low melting point and usually requires regenerative cooling to work.
Chemical engines are actually harder to create as you can't just rely on increasing mass flow rate to cool the engine down.
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Post by Zerraspace on Oct 3, 2016 19:53:38 GMT
Elouda, I used the specs of your decane NTR as a basis to improve my own engines, and though I wasn't able to improve thrust all that much, I was able to make them a lot smaller and so improve TWR. That let me finally fit good gimbals on them, and now all my ships have turnabout under 5 seconds - at least except the giants, but they're much improved too. Virgil II can turnabout in 40, and Virgil III is down from 20 minutes to 2. It might actually be playable now... Thanks!
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Post by randomletters on Oct 3, 2016 23:15:55 GMT
I still can't make heads or tails of reactors, but here's the best I've managed with railguns since the 1.02 patch.  The turret could use some work but it scales reasonably well up and down, to a maximum of about 80 km/s on a 50m barrel. I just couldn't figure out any way to mount that barrel onto a ship and still have a usable weapon. |
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acatalepsy
Junior Member
Not Currently In Space
Posts: 97 
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Post by acatalepsy on Oct 4, 2016 0:26:48 GMT
Right. I think we're establishing that whatever was done to the coilgun and railgun calculations, it was very much not enough. The total power output of that gun is something like .15 Gigwatts, on an input power of 6.40 Megawatts. This is Not How Physics Works, to put it mildly.
A quick sanity check method for your railgun and coilgun designs: the total power output of a gun is .5 * (Muzzle Velocity)^2 * (Projectile Mass) / (Reload Time). If it's more than the input power, you have what is referred to as A Problem.
EDIT: Copied down result wrong, was .15 GW and not 1.5 GW.
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Post by randomletters on Oct 4, 2016 1:01:40 GMT
Right. I think we're establishing that whatever was done to the coilgun and railgun calculations, it was very much not enough. The total power output of that gun is something like 1.5 Gigwatts, on an input power of 6.40 Megawatts. This is Not How Physics Works, to put it mildly. A quick sanity check method for your railgun and coilgun designs: the total power output of a gun is .5 * (Muzzle Velocity)^2 * (Projectile Mass) / (Reload Time). If it's more than the input power, you have what is referred to as A Problem. *Sustained input power of 6.4 Megawatts, I would guess there's some capacitors in there somewhere. It's still broken as all hell though. I just generally assume anything with more than 10 km/s isn't working as intended at this point. Where'd you get that formula? I'd love to do some more reading on coil/railguns. Edit: After plugging in the numbers either I've forgotten a LOT of my physics or you transcribed that formula wrong. .5 * 50^2 km/s * 1g/0.08s .5 * 2500 km/s * 12.5 g/s 1250 km/s * 12.5 g/s 15625 km*g/s = m*kg/s 1593 W |
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Post by jakjakman on Oct 4, 2016 1:52:55 GMT
Quick dumb question: Anyone know where to find the UserDesigns.txt file on a Mac?
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Post by pokington on Oct 4, 2016 2:36:07 GMT
*Sustained input power of 6.4 Megawatts, I would guess there's some capacitors in there somewhere. It's still broken as all hell though. I just generally assume anything with more than 10 km/s isn't working as intended at this point. Where'd you get that formula? I'd love to do some more reading on coil/railguns. Edit: After plugging in the numbers either I've forgotten a LOT of my physics or you transcribed that formula wrong. .5 * 50^2 km/s * 1g/0.08s .5 * 2500 km/s * 12.5 g/s 1250 km/s * 12.5 g/s 15625 km*g/s = m*kg/s 1593 W Units, my friend, units. (50 km/s)^2 is not 2500 km/s. |
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acatalepsy
Junior Member
Not Currently In Space
Posts: 97
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Post by acatalepsy on Oct 4, 2016 2:48:18 GMT
*Sustained input power of 6.4 Megawatts, I would guess there's some capacitors in there somewhere. It's still broken as all hell though. With a sustained output power of 1.5 Gigawatts, so no, very definitely physics breaking. Where'd you get that formula? I'd love to do some more reading on coil/railguns. Edit: After plugging in the numbers either I've forgotten a LOT of my physics or you transcribed that formula wrong. .5 * 50^2 km/s * 1g/0.08s .5 * 2500 km/s * 12.5 g/s 1250 km/s * 12.5 g/s 15625 km*g/s = m*kg/s 1593 W That's the formula for kinetic energy of an object, divided by the fire rate. As an example, if you fire a 1 kilogram object out of a railgun at 1 meter per second every second, you're producing power equivalent to .5 * (1 m/s)^2 * (1 kg) / (1s), you're producing .5 kg m^2 / s^3, or .5 Watts - IE, the power you'd be extracting from the gun if you used the projectile to push a (perfectly efficient) wheel or something. The formula is perfectly fine, you did your unit conversion wrong. (50 km/s)^2 isn't 2500 km/s, it's 2500 km^2/s^2, or (2500 km^2/s^2)(1000 m/km)(1000 m/km) - or 2,500,000,000 m^2/s^2. If you don't want to deal with unit conversions, I'd suggest using Alpha, which can handle a lot of it automatically. ...also I did get it wrong, it's .15 GW (or 150 MW), but that's just because I copied the result down wrong to the forum . Still breaks physics! |
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Post by jakjakman on Oct 4, 2016 5:13:50 GMT
Okay, I threw this together to get through Vesta Overkill... but something is confusing me. I picked the 60MW generator so I could fire all the lasers and the coil gun at the same time. For some reason it's only using one at a time even though there's plenty of power available. What am I doing wrong here? How do I get everything firing simultaneously?  |
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Post by elouda on Oct 4, 2016 5:43:39 GMT
Note that the weapons will also need power for the reaction wheels. On the 286mm, thats another 13MW per gun. For the lasers its less, but probably still a few MW.
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Post by randomletters on Oct 4, 2016 7:22:42 GMT
The formula is perfectly fine, you did your unit conversion wrong. (50 km/s)^2 isn't 2500 km/s, it's 2500 km^2/s^2, or (2500 km^2/s^2)(1000 m/km)(1000 m/km) - or 2,500,000,000 m^2/s^2. If you don't want to deal with unit conversions, I'd suggest using Alpha, which can handle a lot of it automatically. ...also I did get it wrong, it's .15 GW (or 150 MW), but that's just because I copied the result down wrong to the forum . Still breaks physics! I see, thanks for the help. It's a shame but it doesn't seem like the base laser designs can be improved much, has anyone had luck with getting noticeable improvements out of them? |
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acatalepsy
Junior Member
Not Currently In Space
Posts: 97
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Post by acatalepsy on Oct 4, 2016 12:07:10 GMT
Okay, I threw this together to get through Vesta Overkill... but something is confusing me. I picked the 60MW generator so I could fire all the lasers and the coil gun at the same time. For some reason it's only using one at a time even though there's plenty of power available. What am I doing wrong here? How do I get everything firing simultaneously? Look at the weapons icons in the battle display. There should be a flashing icon telling you why it isn't firing. |
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Post by jakjakman on Oct 4, 2016 12:47:43 GMT
Okay, I threw this together to get through Vesta Overkill... but something is confusing me. I picked the 60MW generator so I could fire all the lasers and the coil gun at the same time. For some reason it's only using one at a time even though there's plenty of power available. What am I doing wrong here? How do I get everything firing simultaneously? Look at the weapons icons in the battle display. There should be a flashing icon telling you why it isn't firing. Ahh, looks like I was mistaken. The lasers and coilgun all do fire at the same time. I was interpreting the ship builder as saying it only used power for one weapon at a time. Thanks! Still though, anyone know where to find the UserDesigns.txt file on a Mac computer? |
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Post by nivik on Oct 4, 2016 15:28:10 GMT
The formula is perfectly fine, you did your unit conversion wrong. (50 km/s)^2 isn't 2500 km/s, it's 2500 km^2/s^2, or (2500 km^2/s^2)(1000 m/km)(1000 m/km) - or 2,500,000,000 m^2/s^2. If you don't want to deal with unit conversions, I'd suggest using Alpha, which can handle a lot of it automatically. ...also I did get it wrong, it's .15 GW (or 150 MW), but that's just because I copied the result down wrong to the forum . Still breaks physics! I see, thanks for the help. It's a shame but it doesn't seem like the base laser designs can be improved much, has anyone had luck with getting noticeable improvements out of them? I'm not on my gaming PC right now, but one thing I've noticed is that the thing to optimize for is irradiance at range rather than pure output power. Maximizing irradiance can be done by minimizing divergence, which is done by lowering wavelength (increasing frequency), and by increasing the starting beam width (enlarging the laser aperture). This is kinda counterintuitive, because it means that a more tightly focused beam actually spreads out faster, to the point where the width of the beam will be significantly larger at the target than if you'd widened the beam at the source. I've had a lot of luck with krypton flash tubes, titanium-sapphire lasing rods, and a frequency doubler (don't remember which crystal right now) and very wide aperture sizes to produce fairly effective near-UV lasers with good performance at range. That said, I've mostly focused on low power lasers (less than one megawatt): at higher powers, there's probably other considerations I haven't run into yet. |
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Any tips on developing engines like these? Trial and error or do you all have a method that you follow? (Somebody slap some of these new engines on a Gt-nuke and post the results.)
