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[1.2.1] RLA_Continued 14.0

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Original thread: here

Pictures: here


What is RLA_Stockalike?
"Parts to fill stock niches, including 0.625m LFO engines and tanks, a full suite of monopropellant engines ranging from 2.5m to sub-0.625m, brand new 0.625m SRBs, 0.625m high efficiency engines using LiquidFuel, Monopropellant or Xenon, a number of new probe cores with varied specialisations and shapes, more ways to produce electricity, a range of RCS blocks both large and small, and structural parts to glue it all together with."


What is RLA_Continued?
I've been maintaining a set of patches for RLA_Stockalike for a bit now, and I've decided to take the next step and simply integrate the patches with RLA directly, and redistribute everything as a single package. This is said package.


Other Things:
I realize that @hoojiwana is known for taking relatively long absences from KSP, and will no doubt come riding back into town any day now. It goes without saying that when he does so, I will gladly step aside and hand over control of this continuation to him to use as he sees fit. I am very much aware that this is his mod, not mine.



@hoojiwana as far as I know, has no knowledge of this continuation; as per license requirement, I cannot and do not claim that he has endorsed these changes, for I have had (despite my best efforts) no contact with him.:(



@hoojiwana is the original creator of RLA_Stockalike.

@Deimos Rast is the current maintainer of RLA_Continued, and author of the changes contained therein.


Installation Instruction:
- Please uninstall all previous versions prior to updating RLA to the latest version.
- Place RLA_Stockalike folder into GameData directory.
- Has no dependencies (Module Manager is optional)


Github (repo)
CKAN (soon)


Soon (maybe)

Edited by Deimos Rast
update v14.0.1a
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On 18. 1. 2017 at 7:53 AM, the_machemer said:

Thanks to you, my mod list is now fully updated. Divines bless your kind heart! May the ground you walk quake as you pass!

On a side note, anyone know if RealPlume Stock Configs still works with this?

I did not make complete test, but it seemed as it does. I think also real fuels (and respective cfg for real plume) did work... But I am not sure, and not at my pc just now.

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On 1/18/2017 at 6:53 AM, the_machemer said:

Thanks to you, my mod list is now fully updated. Divines bless your kind heart! May the ground you walk quake as you pass!

On a side note, anyone know if RealPlume Stock Configs still works with this?

Yeap, it does :cool:.

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I did some basic math, and it looks like the LV-Nc ("Mighty") is a little too massive.

The drop in Isp makes sense: smaller reactor leading to lower temperature and thus lower exhaust velocity (ve (and thus Isp) is proportional to sqrt(T) (T is temperature in Kelvin)). The problem is how well a lump of radioactives that small can heat our exhaust (ie, Isp might be too high! (don't want to go there, though))

The drop in thrust also makes sense, but is a fair bit more complicated:

  • F = me ve and ve is as above.
  • me is proportional to both the cross section area of the nozzle throat and sqrt(T). [careful: this might cause one to think me is proportional to ve (and thus Isp), but ve depends on the ratio of internal pressure to external pressure, while me depends only on the internal pressure/temperature. however, the relationship does hold for the same conditions so using vacuum Isp should be valid].

I loaded the models for both the LV-N and the LV-Nc into blender and did some measurements. The outside diameters of the nozzle throats are 0.258m for the LV-N and 0.091m for the LV-Nc. Assuming the all-important inside diameters scale the same way (a reasonable assumption, see below), this gives and area ratio of (0.091/0.258)2, or 0.1244. With a vacuum Isp ratio of 750/800, this puts the me ratio at 0.1148, and a thrust ratio of 0.1076 since thrust winds up proportional to area and the square of Isp.

The above puts my estimate of the thrust at 6.45kN instead of the current 6kN. However, I'm not quite so worried about this.

As a very rough estimate of the mass ratios of the engines, I measured the mesh volumes of the two engines in blender (after editing them some to seal off non-manifold parts and merge the bell with the engine for the LV-N). This put the volumes at 1.44m3 for the LV-N and 0.11m3 for the LV-Nc.

As the mass of a pressure vessel (which an engine is) is directly proportional to its volume (for a constant internal pressure, which I am assuming for these calculations), the masses of the engines should be proportional to their volumes (interestingly, this seems to include structural parts). This puts the mass ratio at 0.11/1.44 or 0.0764, giving a mass of 0.23t for the LV-Nc (vs its current 0.32t).

In summary, I think the thrust should be increased from 6kN to 6.45kN (maybe, less fussed about this) and the mass reduced from 0.32t to 0.23t, changing the TWR from 18.75 to a bit over 28 (compared to the LV-Ns TWR of 20). This makes sense as, all else being equal, engines follow the cube-square law for scaling (volume and thus mass with the cube of the scale, throat area and thus thrust going with the square of the scale). (if it was just a straight 1/2 scaling for the engine, I'd say the mass would be 0.375t and the thrust 15kN, but that would put the TWR at 40, and it's not a straight scaling anyway)

[edit]I had goofed with the straight-scale mass: I did 6/8 instead of 3/8 (corrected now)

Edited by taniwha
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Just want to step by and say thank you all who made/maintain this mod!

For me - a person that tests out almost every mods in soe save but in his career uses just a handfull - this mod is just pure gold.

I would say you can't get closer to stock as this mod. And while staying 99.3% stock it really makes monoprop usefull again instead of beeing just useless weight.

Thank you!!!

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Is this mod actually actively maintained? The balance of the monoprop engines is a bit "off" theyre extremly usefull. I don't mind usefull engines but it feels almost like cheating.

Edited by maculator
Im stupid
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