[20/11/2014][0.25] FTmN Atomic Rockets

[Starwaster]

Gotta correct/add to this - you're right that the high ISP is/was due to the fact that the working fluid (e.g. the propellant) was hydrogen. But you have to remember the other big factor in real-world ISP: exhaust velocity. NERVA had insanely high exhaust velocity, and it it obtained that high exhaust velocity due to a really, really high energy flux to heat and expand the working fluid to those high velocities. Without something like VASIMIR (which hasn't even reached scales of the Timberwind NERVA tests), the only way to get those high exhaust velocities at the same mass flow rates to give good thrust is to use a nuclear thermal core.

So .... anyway, just read Kommitz's plan for the next update and I can't wait. I heart these engines so much.

Yes, I'm well aware that Isp derives from exhaust velocity. You can't know a rocket's Isp without first determining exhaust velocity. That's fairly basic.

But you don't get there by heat alone. Otherwise you'd just stick with chemically fueled rockets of which there's quite a few with higher chamber temperatures than NERVA.

Try some other propellant and your exhaust velocity will be considerably lower than with H2.

And Timberwind / NERVA are two different projects with very different types of reactors. NERVA was born of Project Rover (1950s - late 1960s) and Timberwind was part of SDI in the 80s. Timberwind didn't even really get out of the theoretical stage whereas Rover had actual reactors with dozens of test firings.

[Kommitz]

Also I'm wondering if the mod includes liquid or gas core nukes at all? (more ISP )

Soonâ„¢. Currently doing some very comprehensive planning with regards to tubes. I really like how I they look on that FTmN 400 so expect many more (even if they are serious polygon hogs...).

(Please, really do not analyse the symbols utilised in this illustration if you are remotely familiar with electronics or hydraulics).

Edited December 30, 2014 by Kommitz

[Starwaster]

I know we're not supposed to analyze it, but I'm calling it right now. It's a part that stuff goes into the thingy on top and then more stuff comes out of the bottom and propels the rocket forwards...

[aradapilot]

Eagleshift: looks like kommitz approved adding this to ckan, would love to see it there by the next release

in case the post gets lost in history:

http://forum.kerbalspaceprogram.com/threads/26286-20-11-2014-0-25-FTmN-Atomic-Rockets?p=1552718&viewfull=1#post1552718

[LameLefty]

Yes, I'm well aware that Isp derives from exhaust velocity. You can't know a rocket's Isp without first determining exhaust velocity. That's fairly basic.

But you don't get there by heat alone. Otherwise you'd just stick with chemically fueled rockets of which there's quite a few with higher chamber temperatures than NERVA.

Um, try not being so defensive and, you know, actually reading what I wrote. I didn't write "temperature," I wrote "energy flux." I was precise, and I was so for a reason.

And with regard to the differences between NERVA and Timberwind, they're irrelevant to the discussion at hand - both were NTR rocket designs and neither one of them ever came close to a flight-qualified design. Having actually designed mission- and crew-critical spaceflight hardware (which hardware now has many years' flight experience behind it), I know the differences between prototype and production hardware very well.

[Starwaster]

Um, try not being so defensive and, you know, actually reading what I wrote. I didn't write "temperature," I wrote "energy flux." I was precise, and I was so for a reason.

When I get defensive, you'll know it.

And with regard to the differences between NERVA and Timberwind, they're irrelevant to the discussion at hand - both were NTR rocket designs and neither one of them ever came close to a flight-qualified design. Having actually designed mission- and crew-critical spaceflight hardware (which hardware now has many years' flight experience behind it), I know the differences between prototype and production hardware very well.

If they weren't relevant then you shouldn't have introduced them into the conversation. When you do so you invite commentary and feedback. You're not just throwing them out into a vacuum.

[LameLefty]

When I get defensive, you'll know it.

I communicate for a living these days. You sure seemed defensive. PROTIP: Get that chip off your shoulder before you reply to an internet post.

If they weren't relevant then you shouldn't have introduced them into the conversation. When you do so you invite commentary and feedback. You're not just throwing them out into a vacuum.

I introduced real-world NTR's merely to point out heat-flux, not just choice of propellant, matters most of all. For that matter, given the low density of LH2 and the attendant volume (and mass) of tankage required, a higher molectular-weight propellant such as ammonia might be an even better real-world propellant.

Edited January 3, 2015 by LameLefty

[passinglurker]

Hey kompiz with the growing number of 1.875 packs(HGR, Tantares, Socke's...) would it possible to get a version of the medium NTR with a 1.875 sized thrust plate?

[Kommitz]

I'm just sorting out some switchable baseplates for these (when I'm working on them...), using Firespitter of course. So I should be able to offer a 1.875m option easily enough :>

[edemlama]

do they work in 1.0?

[sojourner]

The attach nodes don't seem to work anymore. You can put them on a rocket but not attach anything under them in the stack. Any one know if this can be fixed by editing the cfg files?

[NoMrBond]

The attach nodes don't seem to work anymore. You can put them on a rocket but not attach anything under them in the stack. Any one know if this can be fixed by editing the cfg files?

Changing the sign on the 5th number on the node_stack_bottom line should fix it (it will probably need to be made negative)

[Mecripp]

If you know how to edit the cfg it's easy and a quick fix.

@PART[ftmn400]
{
  @node_stack_bottom = 0.0, -3.1, 0.0, 0.0, -1.0, 0.0, 3
}

@PART[ftmn180]
{
  @node_stack_bottom = 0.0, -2.735, 0.0, 0.0, -1.0, 0.0, 2
}

@PART[ftmn80]
{
  @node_stack_bottom = 0.0, -1.835, 0.0, 0.0, -1.0, 0.0, 1
}

@PART[bl40n]
{
  @node_stack_bottom = 0.0, -2.0, 0.0, 0.0, -1.0, 0.0, 1
}

[Prowler_x1]

If you know how to edit the cfg it's easy and a quick fix.

@PART[ftmn400]
{
  @node_stack_bottom = 0.0, -3.1, 0.0, 0.0, -1.0, 0.0, 3
}

@PART[ftmn180]
{
  @node_stack_bottom = 0.0, -2.735, 0.0, 0.0, -1.0, 0.0, 2
}

@PART[ftmn80]
{
  @node_stack_bottom = 0.0, -1.835, 0.0, 0.0, -1.0, 0.0, 1
}

@PART[bl40n]
{
  @node_stack_bottom = 0.0, -2.0, 0.0, 0.0, -1.0, 0.0, 1
}

What about a power re-balance for v1.0.2

[NoMrBond]

What about a power re-balance for v1.0.2

Unfortunately working out the new thrust values is a lot more faffing about than flipping the sign for the Y stack vector :\

[Prowler_x1]

Unfortunately working out the new thrust values is a lot more faffing about than flipping the sign for the Y stack vector :\

any clues as to where to look for documentation on that subject? I may do the rebalance my self if I knew what the changes were.

[Mecripp]

What you wanting to change ?

EDIT- If you know how to edit which easy you can with any text editor will open the cfg, I posted the names so you have that much.

@PART[ftmn400]
{
  @node_stack_bottom = 0.0, -3.1, 0.0, 0.0, -1.0, 0.0, 3
  @maxTemp = 2000 // = 3600
  @stagingIcon = LIQUID_ENGINE

  @MODULE[ModuleEnginesFX]
    {
      EngineType = LiquidFuel

      @atmosphereCurve
        {
          key, 2 = 7 0.001 
        } 
     }    
}

@PART[ftmn180]
{
  @node_stack_bottom = 0.0, -2.735, 0.0, 0.0, -1.0, 0.0, 2
}

@PART[ftmn80]
{
  @node_stack_bottom = 0.0, -1.835, 0.0, 0.0, -1.0, 0.0, 1
}

@PART[bl40n]
{
  @node_stack_bottom = 0.0, -2.0, 0.0, 0.0, -1.0, 0.0, 1
}

Edited May 8, 2015 by Mecripp2

[NoMrBond]

any clues as to where to look for documentation on that subject? I may do the rebalance my self if I knew what the changes were.

Nothing I've seen as yet, still working through the changes myself

It may be as simple as adding and additional argument to their MODULE{name = ModuleEnginesFX ... } in the config

EngineType = LiquidFuel to anything LANTR (i.e. using LF/O) and EngineType = Nuclear to anything NTR (LF only)

Not something I can check right now unfortunately

[Mecripp]

I think the EngineType = LiquidFuel just give IVA view a little shake.

[Kommitz]

Oh dear, what's happening in here? I'll give the new part configs a look and see about rebalancing everything.

I have otherwise been distracted by modding different games, so hi after however many months it's been.

[Mecripp]

Just Squad changing things why your away

[Kolago]

Great to see you back here!

[Surefoot]

Hey we've been happily using your mod, and will happily do so if you update it for 1.0+

POWAAAAAA

[sojourner]

Oh dear, what's happening in here? I'll give the new part configs a look and see about rebalancing everything.

I have otherwise been distracted by modding different games, so hi after however many months it's been.

Is it just the part configs? I tried poking around in one, but I don't know enough of how engine configs work to fix things. I'm hoping it's just hte configs as I still have your two earlier versions of this mod with the older models and hope to get them working as well. Even if your not up to updating them, I figure if I can see working configs for the latest version of the mod I can do some copy&pasting to get the older versions to work. I like the variety of having all those different atomic engines to choose from.

[Prowler_x1]

What you wanting to change ?

EDIT- If you know how to edit which easy you can with any text editor will open the cfg, I posted the names so you have that much.

@PART[ftmn400]
{
  @node_stack_bottom = 0.0, -3.1, 0.0, 0.0, -1.0, 0.0, 3
  @maxTemp = 2000 // = 3600
  @stagingIcon = LIQUID_ENGINE

  @MODULE[ModuleEnginesFX]
    {
      EngineType = LiquidFuel

      @atmosphereCurve
        {
          key, 2 = 7 0.001 
        } 
     }    
}

@PART[ftmn180]
{
  @node_stack_bottom = 0.0, -2.735, 0.0, 0.0, -1.0, 0.0, 2
}

@PART[ftmn80]
{
  @node_stack_bottom = 0.0, -1.835, 0.0, 0.0, -1.0, 0.0, 1
}

@PART[bl40n]
{
  @node_stack_bottom = 0.0, -2.0, 0.0, 0.0, -1.0, 0.0, 1
}

Thank you much for the imput. I had done the node bottom changes by hand and now that Kommitz is back I cant wait for the author to retake this mod to a new level. These are the best looking engines in KSP by far. I've been having some issues with textures disappearing from models in opengl mode. is anyone suffering from this?

Edited May 19, 2015 by Prowler_x1