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Post by qswitched on Jan 8, 2017 23:21:47 GMT
Awesome! I figured this would happen eventually, as all the pieces to do it were there. However, as demonstrated, the efficiency is horrible without the 'shaping' of the plasma into a cigar. It's quite underwhelming without being able to concentrate all that power into a single jet.
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Post by The Astronomer on Jan 9, 2017 3:25:07 GMT
I hope I can apply some oil on the pusher plate. They said a pusher plate that has some oil on it won't ablate. (The researcher accidentally applied oil from their fingers, and those fingerprints didn't ablate.)
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Post by The Astronomer on Jan 9, 2017 3:29:13 GMT
Awesome! I figured this would happen eventually, as all the pieces to do it were there. However, as demonstrated, the efficiency is horrible without the 'shaping' of the plasma into a cigar. It's quite underwhelming without being able to concentrate all that power into a single jet. Even without shaping, the effects are already overwhelming for my prototypes...
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Post by Hicks on Jan 9, 2017 5:42:44 GMT
Hey! I just saw something: because I mounted the launcher on the nose, the nuke comes out with it's nose out too. This means we can wrap it in depleted uranium "armor" and have a "rad shield" of tungsten on the back where the armor won't cover anyway, which provides a perfect shape to focus the nuclear blast! I'm gonna test this right now.
Edit update: tungsten rhenium is now the launcher armor of choice. Lasted longer than a 3m thick maraging steel pusher plate, which lasted 300 2kt detonations at 50m.
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Post by Hicks on Jan 9, 2017 8:05:47 GMT
Hey qswitched, I really like how you modeled the visuals in the game to reflect what we should see in real life, it let's me check for the defraction caused by the wave of plasma just after the nuke flash. That's pretty awesome.
In other news, a launcher armored with 1m of tungsten rhenium lasted 457 pulses of a 2kt detonation, propelling a ~250kg of tungsten and beryllium oxide plasma. The newer, lighter, cheaper 20m radius 3m thick silica aerogel pusher plate took it like a champ and is still good.
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Post by zorbeltuss on Jan 9, 2017 10:23:03 GMT
So my ship doesn't move at all, after 10k pulses, but then again my ship survives 10k pulses which is something at least, yes I know it can barely rotate at all, yes I know it has a way to small pusher plate (which is actually not needed for this design but removing it entirely looked to silly), those were weight savings made to make my ship move. Before this I did a few iterations without tungsten in the payload just to make sure the now more or less non-existent pusher plate didn't melt then calculating distance and I made sure that the distance with the tungsten would be plasma was the same, only after did I scale down the pusher plate. Album of pictures
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Post by The Astronomer on Jan 9, 2017 10:49:25 GMT
So my ship doesn't move at all, after 10k pulses, but then again my ship survives 10k pulses which is something at least, yes I know it can barely rotate at all, yes I know it has a way to small pusher plate (which is actually not needed for this design but removing it entirely looked to silly), those were weight savings made to make my ship move. Before this I did a few iterations without tungsten in the payload just to make sure the now more or less non-existent pusher plate didn't melt then calculating distance and I made sure that the distance with the tungsten would be plasma was the same, only after did I scale down the pusher plate. Album of picturesWhere is the pusher plate?
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Post by zorbeltuss on Jan 9, 2017 10:56:25 GMT
So my ship doesn't move at all, after 10k pulses, but then again my ship survives 10k pulses which is something at least, yes I know it can barely rotate at all, yes I know it has a way to small pusher plate (which is actually not needed for this design but removing it entirely looked to silly), those were weight savings made to make my ship move. Before this I did a few iterations without tungsten in the payload just to make sure the now more or less non-existent pusher plate didn't melt then calculating distance and I made sure that the distance with the tungsten would be plasma was the same, only after did I scale down the pusher plate. Album of picturesWhere is the pusher plate? That's the 1 cm highly angular VC Steel that glows in some pictures, before cutting it down to a minimum it was 10 m radius 1 m VC Steel, 0.5 m Graphite Aerogel and 2.5 m Tungsten, it actually makes no difference as the radiated heat from the nuke doesn't affect it and the launcher itself is perfectly capable of withstanding the NEFP thrown at it, had there been a plasma implementation though the current pusher plate would have given way easily.
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Post by The Astronomer on Jan 9, 2017 11:01:25 GMT
Where is the pusher plate? That's the 1 cm highly angular VC Steel that glows in some pictures, before cutting it down to a minimum it was 10 m radius 1 m VC Steel, 0.5 m Graphite Aerogel and 2.5 m Tungsten, it actually makes no difference as the radiated heat from the nuke doesn't affect it and the launcher itself is perfectly capable of withstanding the NEFP thrown at it, had there been a plasma implementation though the current pusher plate would have given way easily. Uh, I think I see why there's no thrust: the blow just simply flow away due to its shape? Pusher plate needs to be broad to be able to collect as much flow as it can. For my attempt, the problem is its use count: 2. The third blow kills.
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Post by zorbeltuss on Jan 9, 2017 11:09:07 GMT
That's the 1 cm highly angular VC Steel that glows in some pictures, before cutting it down to a minimum it was 10 m radius 1 m VC Steel, 0.5 m Graphite Aerogel and 2.5 m Tungsten, it actually makes no difference as the radiated heat from the nuke doesn't affect it and the launcher itself is perfectly capable of withstanding the NEFP thrown at it, had there been a plasma implementation though the current pusher plate would have given way easily. Uh, I think I see why there's no thrust: the blow just simply flow away due to its shape? Pusher plate needs to be broad to be able to collect as much flow as it can. For my attempt, the problem is its use count: 2. The third blow kills. As said, the pusher plate was 10 m in radius before, it did absolutely nothing then which was why I reduced it.
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Post by The Astronomer on Jan 9, 2017 11:14:12 GMT
Uh, I think I see why there's no thrust: the blow just simply flow away due to its shape? Pusher plate needs to be broad to be able to collect as much flow as it can. For my attempt, the problem is its use count: 2. The third blow kills. As said, the pusher plate was 10 m in radius before, it did absolutely nothing then which was why I reduced it. How heavy is your ship? Mine's just barely over 100 t, and I used 1 Mt bomb. It moved significantly, but too low use time.
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Post by zorbeltuss on Jan 9, 2017 11:21:14 GMT
As said, the pusher plate was 10 m in radius before, it did absolutely nothing then which was why I reduced it. How heavy is your ship? Mine's just barely over 100 t, and I used 1 Mt bomb. It moved significantly, but too low use time. 785 t, with a 950 t bomb, those are in the picture album, after 10k bombs and 3 hours it hadn't moved perceptibly.
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Post by randomletters on Jan 9, 2017 11:49:05 GMT
So I did some quick and dirty math on this 250 ton tester and the results are interesting. 1 999 kg (rounded up to 1000 kg for convenience) nuke accelerates the 250,000 kg ship 20 m/s, this is equivalent to a rocket engine with 5000 m/s exhaust velocity. The ship has 100 nukes and a total weight of 250 tons giving a wet/dry mass ratio of 1.66. This gives us a delta V of roughly 2500 m/s, which is a hell of a lot better than I expected for this. Optimizing the pulse unit (probably just thinning down the tungsten armor) could make this primitive design an actually viable drive system in theory.
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Post by The Astronomer on Jan 9, 2017 11:52:41 GMT
How heavy is your ship? Mine's just barely over 100 t, and I used 1 Mt bomb. It moved significantly, but too low use time. 785 t, with a 950 t bomb, those are in the picture album, after 10k bombs and 3 hours it hadn't moved perceptibly. You probably have to scale that up to about 10kt. I have just found that my bomb are too large. In fact, large enough to cause EMP.
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Post by Hicks on Jan 9, 2017 12:08:59 GMT
You don't need to have a heavy pusher plate. Silica aerogel will catch the plasma and not over heat, just make sure it shadows your ships radiators.
The hardest thing right now is optimizing accelleration. The nose mounted launcher fires the nuke nose first, so I've been placing beryllium oxide and tungsten rad-shields of equal size (about a 1:4 mass ratio) as propellant. The 100kt pulse unit worked the best with the launcher set to 70m. I'll have more when my ISP fixes my modem and I'm no longer tied to this phone.
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