Nertea

[1.7.x] Kerbal Atomics: fancy nuclear engines! (Sept 11)

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Nice! Seems to be working as intended.

Just to confirm, the whole heat jumping up in other parts of the ship after a timewarp is a stock bug correct?

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7 hours ago, Nertea said:

No worries. I just uploaded a fixed version. The version I had uploaded was from a day or so ago, when I hadn't yet fixed stock's auto-disabled radiator thing. 

I'm sorry, I'm confused. Which version of what do I need to download now? I updated NFE earlier today.

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7 hours ago, Businfu said:

Nice! Seems to be working as intended.

Just to confirm, the whole heat jumping up in other parts of the ship after a timewarp is a stock bug correct?

Yes, on over 1000x timewarp the heat gets redistributed.

34 minutes ago, theonegalen said:

I'm sorry, I'm confused. Which version of what do I need to download now? I updated NFE earlier today.

0.7.4, which is the latest version in the NFE thread/all the download locations.

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Would it be possible to add a feature so that the engines could switch between LF and Hydrogen, at the sacrifice of a much lower ISP (But slightly better thrust) Just an idea for a future update

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Hello, I have a question that hopefully isn't too stupid.  I'm new to most of the Kerbal part mods and just thought I would say the quality of these are fantastic.  However, I'm having trouble finding exactly the advantage of using these engines versus the normal chemical engines.  It seems every configuration I try these engines always have less delta-v than the chemical ones.  This image shows what i'm doing, and if I switch out any of the atomic engines the simple skipper always has around 1,000 delta-v more (oh and above that lab is just a command pod).  It was my limited understanding that atomic engines will give the advantage of high delta-v and efficiency at the cost thrust. In my attempts to use these engines it seems the only advantage they seem to hold is a much lower mass, so I'm assuming there is something I'm not understanding correctly?  

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3 hours ago, ScubaSteveWA said:

Hello, I have a question that hopefully isn't too stupid.  I'm new to most of the Kerbal part mods and just thought I would say the quality of these are fantastic.  However, I'm having trouble finding exactly the advantage of using these engines versus the normal chemical engines.  It seems every configuration I try these engines always have less delta-v than the chemical ones.  This image shows what i'm doing, and if I switch out any of the atomic engines the simple skipper always has around 1,000 delta-v more (oh and above that lab is just a command pod).  It was my limited understanding that atomic engines will give the advantage of high delta-v and efficiency at the cost thrust. In my attempts to use these engines it seems the only advantage they seem to hold is a much lower mass, so I'm assuming there is something I'm not understanding correctly?  

I think you're looking at size rather than mass.  Hydrogen isn't very dense compared to other fuels, so  the same size container will hold a lot less of it.  If you increase the amount of hydrogen such that the masses of the two craft you are comparing are similar, you should start to see a benefit.  Or for the same delta-v (whatever your mission requires), you will require less mass (thus requiring a smaller rocket to get it to orbit).

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6 hours ago, BashGordon33 said:

Would it be possible to add a feature so that the engines could switch between LF and Hydrogen, at the sacrifice of a much lower ISP (But slightly better thrust) Just an idea for a future update

Well, there is a patch available in the Kerbal Atomics download that makes the engines use LF I believe. I am not at home so I can not doublecheck. No switching yet though as far as I know. 

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On 5/29/2016 at 8:48 PM, ScubaSteveWA said:

Hello, I have a question that hopefully isn't too stupid.  I'm new to most of the Kerbal part mods and just thought I would say the quality of these are fantastic.  However, I'm having trouble finding exactly the advantage of using these engines versus the normal chemical engines.  It seems every configuration I try these engines always have less delta-v than the chemical ones.  This image shows what i'm doing, and if I switch out any of the atomic engines the simple skipper always has around 1,000 delta-v more (oh and above that lab is just a command pod).  It was my limited understanding that atomic engines will give the advantage of high delta-v and efficiency at the cost thrust. In my attempts to use these engines it seems the only advantage they seem to hold is a much lower mass, so I'm assuming there is something I'm not understanding correctly?  

You need to consider mass vs volume with LH2 fuels. That tank you have contains a minuscule amount of fuel mass vs the LF/O Skipper. If you use a similar total vehicle mass, the nuclear engine will win out easily. Using LH2 is a design challenge faced by real engineers in terms of dealing with boiloff and also large volumes, but has nice gains in possible Isp. If you don't like it, you can you the patch in the Extras folder that switches everything back to LF at the cost of reducing the Isp. 

On 5/29/2016 at 7:11 PM, BashGordon33 said:

Would it be possible to add a feature so that the engines could switch between LF and Hydrogen, at the sacrifice of a much lower ISP (But slightly better thrust) Just an idea for a future update

Because the stock switcher only allows 2 modes, I won't be doing this. 

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All of my atomic engines (Stock/Near F/USI) except Mk2 expansion no longer have reactors. They were there on 5-2-16 around 8pm EST. Did you update something since then that might have broken them, or did I do it installing/uninstalling another mod via ckan? 

AS-1.jpg

I have tried uninstalling and reinstalling NFE & KA, but that didn't solve the issue. Should I go ahead and reinstall all of my mods, or do you have a better suggestion? I have PMed you my mod list, in case it will be any help.

BTW Thanks for all of your work. I Use all of your Near Future mods, and I am looking forward to MkIV being ported to 1.1.2!

 

Edited by Mr_Breeze

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On 5/29/2016 at 8:48 PM, ScubaSteveWA said:

It seems every configuration I try these engines always have less delta-v than the chemical ones.  This image shows what i'm doing, and if I switch out any of the atomic engines the simple skipper always has around 1,000 delta-v more

 

On 5/30/2016 at 10:00 PM, Nertea said:

You need to consider mass vs volume with LH2 fuels. That tank you have contains a minuscule amount of fuel mass vs the LF/O Skipper. If you use a similar total vehicle mass, the nuclear engine will win out easily.

Just now I unlocked the LV-N in my career game and slapped together a deep space booster to see how it compared with your cryogenic engines, and i was stunned to find that the cryogenic engines with LH2 and oxidizer give more dV and higher TWR than NTRs in all cases. Of course I could just use more LH2 tanks for the NTRs, but it seems that in all cases it's cheaper, smaller, and gives more thrust using cryogenic engines instead. Is this intentional? Not that it's a huge problem if chemical rockets are better than thermal rockets, but I thought I'd ask.

EDIT: here are some screenshots to illustrate. The mass of each stage is very close, and in this case the TWR of the nuke is slightly higher, but the cryo engine still gives significantly more dV while being 250% cheaper (10,000 vs 25,000, mostly in fuel tankage). @Vrana Yes I did switch the fuel tanks to work correctly, LH2 only for the nuclear stage.

Imgur isn't working for some reason so here's a link: http://imgur.com/a/cUH70

 

Edited by ruiluth
Added screenshots

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1 hour ago, ruiluth said:

 

Just now I unlocked the LV-N in my career game and slapped together a deep space booster to see how it compared with your cryogenic engines, and i was stunned to find that the cryogenic engines with LH2 and oxidizer give more dV and higher TWR than NTRs in all cases.

 

EDIT: Nevermind. After rereading it seems you are using LH2 tanks.

 

Doesn't sound right to me. Are you sure you switched the tanks from using LH2+Oxidizer (which cryo engines use) to LH2 only (which nukes use)?

 

If you put a nuke under a LH2+Ox tank it will still work but since it doesn't use oxidizer at all you will be hauling a lot of dead weight and end up with a worse dV then cryo engines.

 

Edited by Vrana

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On 30/05/2016 at 3:00 PM, Nertea said:

Because the stock switcher only allows 2 modes, I won't be doing this. 

Oh all right, then. It's not that big of a deal. I probably sounded stupid anyway, real life NTRs don't use regular rocket propellant because it can destroy the reactor. I've also had a lot of problems with the nuclear reactors in this mod (and NF electrical now that I mention it.) I tried running my reactor at full heat without using the thrust so I could keep it hot and still get good ISP. I don't really understand what the numbers in the details of the rocket meant. The information under 'Core Heat', 'Fission flow radiator' and 'Fission Reactor' make no sense to me. I don't even know what the 'Fission flow radiator is'

 

On 29/05/2016 at 6:37 PM, ChainiaC said:

Well, there is a patch available in the Kerbal Atomics download that makes the engines use LF I believe. I am not at home so I can not doublecheck. No switching yet though as far as I know. 

Yeah I know but I meant as a 'toggle fuel' button in game

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Hello friends! I'm using this mod with the liquid fuel patch and I find the costs of the engines very low. LV100, LVN50 and LVN500 cost 3500 kerbucks while LVNGE cost 9100. Is this intended this way? Am I missing something? Best wishes!

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Just a balance note

The nova seems underpowered.

 

The LV-N weighs 2.5, provides 60 thrust, and has isp of 900. This is a Thrust/weight ratio of 24 with an isp of 900. Wheras the Nova only has a T/W ratio of 22.2 and an isp of 800. So it's inferior in every way.

 

Now I just looked at the wiki and it says the LV-N weighs 3 tons, so I'm wondering if a mod I got (vens stock part revamp?) changed the weight of the lv-n to 2.5 from 3. But even at a weight of 3, it's a T/W ratio of 20 with isp 900, vs the nova which is still 22.2 and 800. I think in most cases, why wouldn't I want the higher isp? Thats 12.5% more dV for a  very slightly lower TWR on my spacecraft. I would think that a matching isp on the nova of 900, or a higher thrust to compensate for the slightly lower isp, would be a good reason to use the nova over 3 LV-N's.

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On 6/2/2016 at 4:28 PM, Kerbonaut257 said:

Just a balance note

The nova seems underpowered.

 

The LV-N weighs 2.5, provides 60 thrust, and has isp of 900. This is a Thrust/weight ratio of 24 with an isp of 900. Wheras the Nova only has a T/W ratio of 22.2 and an isp of 800. So it's inferior in every way.

 

Now I just looked at the wiki and it says the LV-N weighs 3 tons, so I'm wondering if a mod I got (vens stock part revamp?) changed the weight of the lv-n to 2.5 from 3. But even at a weight of 3, it's a T/W ratio of 20 with isp 900, vs the nova which is still 22.2 and 800. I think in most cases, why wouldn't I want the higher isp? Thats 12.5% more dV for a  very slightly lower TWR on my spacecraft. I would think that a matching isp on the nova of 900, or a higher thrust to compensate for the slightly lower isp, would be a good reason to use the nova over 3 LV-N's.

Not sure what you mean... the Nova isn't an engine from this pack?

On 5/31/2016 at 3:01 AM, BashGordon33 said:

Oh all right, then. It's not that big of a deal. I probably sounded stupid anyway, real life NTRs don't use regular rocket propellant because it can destroy the reactor. I've also had a lot of problems with the nuclear reactors in this mod (and NF electrical now that I mention it.) I tried running my reactor at full heat without using the thrust so I could keep it hot and still get good ISP. I don't really understand what the numbers in the details of the rocket meant. The information under 'Core Heat', 'Fission flow radiator' and 'Fission Reactor' make no sense to me. I don't even know what the 'Fission flow radiator is'

 

Yeah I know but I meant as a 'toggle fuel' button in game

You should clarify the use of the NFE reactors first. Understanding those is pretty key to trying the more advanced versions contained in the engines. 

On 5/31/2016 at 1:41 AM, ruiluth said:

 

Just now I unlocked the LV-N in my career game and slapped together a deep space booster to see how it compared with your cryogenic engines, and i was stunned to find that the cryogenic engines with LH2 and oxidizer give more dV and higher TWR than NTRs in all cases. Of course I could just use more LH2 tanks for the NTRs, but it seems that in all cases it's cheaper, smaller, and gives more thrust using cryogenic engines instead. Is this intentional? Not that it's a huge problem if chemical rockets are better than thermal rockets, but I thought I'd ask.

EDIT: here are some screenshots to illustrate. The mass of each stage is very close, and in this case the TWR of the nuke is slightly higher, but the cryo engine still gives significantly more dV while being 250% cheaper (10,000 vs 25,000, mostly in fuel tankage). @Vrana Yes I did switch the fuel tanks to work correctly, LH2 only for the nuclear stage.

Imgur isn't working for some reason so here's a link: http://imgur.com/a/cUH70

 

Dry mass. That LV-N weighs in at 2.25t, which is considerably heavier than the really light cryo engine (0.7t or something?). The dry mass of the nuclear vehicle is therefore significantly higher than the chemical vehicle, which will significantly impact the DV you get. The LV-N weighs a good 1/4 of the total mass of that ship! Chemical engines will always be better at pushing small payloads than nuclear ones, just because they are a lot lighter. So that's pretty expected. As the ship total size gets larger the huge Isp advantage will start to counter that. 

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23 minutes ago, Nertea said:

You should clarify the use of the NFE reactors first. Understanding those is pretty key to trying the more advanced versions contained in the engines. 

Oh thanks, I'll look over those first. When I started my game for the first time, I just download every mod you made (because their awesome) and I unlocked the Nerv before any reactor. I'll test the reactors in Sandbox mode

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15 hours ago, Nertea said:

Not sure what you mean... the Nova isn't an engine from this pack?

 

Lol. You must hate me by now. Every issue I've brought up has actually had nothing to do with you :P

 

But seriously I have no idea where the Nova engine comes from then!? Probably ven's stock part revamp. No worries Nertea. You're the bomb. Keep on truckin.

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22 hours ago, Nertea said:

Chemical engines will always be better at pushing small payloads than nuclear ones, just because they are a lot lighter. So that's pretty expected. As the ship total size gets larger the huge Isp advantage will start to counter that. 

That makes sense, I probably should have thought of that, haha. I did some more testing and that was in fact true, but I did run into the issue of cost. I had a 75.000-t test payload, and I tried a thermal booster and a chemical booster with a similar TWR and the thermal rocket did give about 30% more dV, but at about 175% higher price. I then tried a chemical booster of about the same price as it gave about 50% higher dV with twice as high of a TWR. A booster of approximately the same price and dV of the smaller chemical rocket had only 25% the TWR, although it weighed 50% less.

Of course I expect nuclear engines to be expensive, but again it seems that chemical cryogenic engines seem to always be more efficient when cost and TWR are taken into account (although nuclear engines do save weight because their fuel is so much lighter). This is also using the stock LV-N which costs substantially more than your more advanced ones, but the performance is fairly similar with the lower-tech engines in Kerbal Atomics, albeit at a higher price.Although the cryogenic tanks needed to store the hydrogen are quite expensive too, so the high price may just be due to the increased tank volume. This would pretty much restrict their usage to sandbox mode or very late-game, since the Liberator does give significantly better performance, possibly enough to offset this. Again, this isn't a big problem but I'm curious what you think about it, as the developer.

Here's another link if you're interested in specific numbers: http://imgur.com/a/q1YKt

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@ruiluth Conventional chemical engines will probably always be the most cost effective option for a single-use craft. Expensive high-ISP engines eventually pay off in refueling costs for reusable craft.

Edited by Fraz86

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@ruiluth Also consider that a smaller mass means you need less rocket to get it to orbit in the first place.  Even if the payload is more expensive, you may still save money by requiring a smaller launch vehicle.

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On 6/4/2016 at 0:14 PM, Kerbonaut257 said:

Lol. You must hate me by now. Every issue I've brought up has actually had nothing to do with you :P

 

But seriously I have no idea where the Nova engine comes from then!? Probably ven's stock part revamp. No worries Nertea. You're the bomb. Keep on truckin.

The Nova comes from Ven's Stock Revamp.

Edited by GregroxMun

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On 1/22/2016 at 3:20 PM, Nertea said:

Snippy snip snip

When you download this mod, is it meant for other Nuclear engines not in the mod to require liquid Hydrogen as well?

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4 hours ago, Spaceception said:

When you download this mod, is it meant for other Nuclear engines not in the mod to require liquid Hydrogen as well?

There is a folder inside the KerbalAtomics folder called Patches which contains scripts to refit a bunch of other mods' NTRs to use LH2.

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First thanks for all these great mods.    I do have an issue which I cannot solve with this mod.   When I install this mod and I am pretty good working with PC's files, editing etc......all my nuclear engines like the 'MRS Nuclear Quad 3.5' and the 'RS-2 'Tiny'  Nuclear Engine'  are converted from Liquid Fuel consumption to Hydrogen.   Any missions in progress utilizing these nuclear engines become inoperable as its fuel source has been redesignated from Liquid Fuel to Hydrogen.    After these missions are complete I plan to install this mod and use Hydrogen.  In the meantime I cannot design any new craft using nuclear engines so to avoid the same problem   Is this the way this mod is supposed to work ?  

Thanks

 

Dave T

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