Jump to content

[1.11.x] Cryogenic Engines: Liquid Hydrogen and Methane Rockets! (Mar 9, 2021)


Recommended Posts

Repo is up and functional, pull request away. I fixed a few things in the meantime.

I'm going to start working on clusterable no-ring versions of the engines. I'm not sure what to do with the gimbal hydraulics though. Generally the pistons extend out to the edge of the ring except for in a few cases. To make a good looking clusterable engine I'll need to address this in one of 3 ways:

  1. Do nothing, the upper piston mounts floating at the deleted ring's edge is ok
  2. Move the upper piston mounts inwards as much as possible without breaking the connections to minimize the radius of the top of the engine
  3. Remove the pistons entirely

What's the best option?

Would you consider making a plugin for the Rapier (and the Broadsword from your own Mk4 mod) to use LH2/LOX instead of LF/LOX during closed cycle alongside an increased ISP of 460 (or a bit less if you want to balance it with the regular cryogenics)? Open cycle would still use LF.

You can do that yourself with MM pretty easily :).

Link to post
Share on other sites
Repo is up and functional, pull request away. I fixed a few things in the meantime.

I'm going to start working on clusterable no-ring versions of the engines. I'm not sure what to do with the gimbal hydraulics though. Generally the pistons extend out to the edge of the ring except for in a few cases. To make a good looking clusterable engine I'll need to address this in one of 3 ways:

  1. Do nothing, the upper piston mounts floating at the deleted ring's edge is ok
  2. Move the upper piston mounts inwards as much as possible without breaking the connections to minimize the radius of the top of the engine
  3. Remove the pistons entirely

What's the best option?

Maybe cluster engines shouldn't gimbal?

Link to post
Share on other sites

It's not going to be a cluster, it's just going to be a version of the engine model that lacks the ring assembly at the top so it is more size-versatile. There's no reason it shouldn't gimbal at all (and it fact, removing ALL the gimbal hardware would be a bunch of work).

Link to post
Share on other sites

If 2's not prohibitively time-consuming, that seems the best option to me. In general you'd want the pistons going up to an (invisible) ring no wider than the nozzle diameter, that should work. Otherwise, I'd guess 3, since in most cases the existing rings are rather too wide to be workable...

Thanks for the repo (and for doing this extra work, and for the mod itself, and...) :)

Link to post
Share on other sites
I'm going to start working on clusterable no-ring versions of the engines. I'm not sure what to do with the gimbal hydraulics though. Generally the pistons extend out to the edge of the ring except for in a few cases. To make a good looking clusterable engine I'll need to address this in one of 3 ways:

  1. Do nothing, the upper piston mounts floating at the deleted ring's edge is ok
  2. Move the upper piston mounts inwards as much as possible without breaking the connections to minimize the radius of the top of the engine
  3. Remove the pistons entirely

What's the best option?

Very excited for this :) I guess the Ct10 and KS-68 are the easy cases because you can just delete the outer ring. The relevant bits might have to have their AO rebaked (or just removed) though - I recall there being a bit of empty space in the texture, so if it's not too much trouble those particular pieces of texture could be duplicated to the empty space. For the Ct65 I think you could just move the struts to the inner ring. The rest are less certain I guess - keep the pistons if possible, but I guess it's still worth asking whether the ring should be removed or just shrunken.

BTW, I don't think it's necessary to make the attachment base as small as possible. If they're the same size as the nozzle, or only slightly bigger, that's probably fine as far as clustering is concerned :)

EDIT: Ninja'd ... I guess you're going with removing the rings then?

Link to post
Share on other sites

Yes, I'm removing the rings as far as I can. It's a bit of a pain, not only am I having to rebake AO, but in some cases I have to add polys and texture to areas that were previously invisible. Luckily, as you point out, there's some space in the texture for a few extra bits. There are also going to be duplicate piston sets in the model for the ringed and bare versions. It looks like it's going well though, the realigned Vulcain is working out alright.

vulcain.png

Unfortunately that's about all I'll be able to do tonight. Will resume at next free time index.

Edited by Nertea
Link to post
Share on other sites

Nertea ... perfect ... can i marry you know?

i always wanted engines, where the attachmentpoint has teh same diameter as the nozzle and not the huge ring/baseplate/tankbottom ... better for clusters.

maybe you can add a tweakconfig , where teh ring/baseplate can be shown like in teh stock reamp mod? so we can build tght clusters or use a single engine as normal with a pretty attachment.

Link to post
Share on other sites

Nertea, awesome!

If anything I'd suggest extending the piston upper bits to rather above the node, so that one can place the engine on a dome, or place 2x around a dome, and not have the arms hanging in the aether. Text example:


| | |
\o/
| |
/ \

where the o is the attach node, and above it run the piston mounting arms and the fuel/ox pipes.

The tough part of course is making sure even the extended bits don't go outside the nozzle diameter....

Link to post
Share on other sites

Maybe I'll save that for a future update, because I finished this just now and want to proceed forwards :).

I'll update the OP album with renders of the frame-less engines at some point, not sure when though.

0.1.10

  • Updated ISFuelSwitch plugin to 1.16
  • Updated to latest CRP version (0.4.4)
  • Updated ModuleManager version (2.6.6)
  • Bundled Mini-AVC for versioning
  • Fixed a capitalization error in CryoEnginesLFO patch
  • Fixed MFT patch to be mutually exclusive with RealFuels
  • Added new versions of all engines that lack the support ring around the top. Toggle in the editor.
  • Added new optional patch: CryoEnginesSurfaceAttach, which allows all engines to be surface attached

Finally! Getting rid of those ugly rings, I can finally make proper engine clusters. Thanks so much!

*sadface* I worked hard on those rings :(.

Edited by Nertea
Link to post
Share on other sites
... Nertea, you are just in time. thank you very much for your fast work :)

and my NASA upperstages look way better with the right engine

DCSS with ring and ACES without rings

http://i.imgur.com/PglhDAT.jpg

http://i.imgur.com/VLN1wAq.jpg

Very nice.

I didn't mean it like that, I just think its good we can make better engine clusters.

I was just kidding ;)

I like the rings can we keep them as an option?

:|

Added new versions of all engines that lack the support ring around the top. Toggle in the editor.
Link to post
Share on other sites

Real LH2/LOx engines (Ariane 5 Vulcain, Delta IV RS-68) runs with mixture ratio 1:6 (and tanks volume ratio is 1:5), why Cryogenic Engines Mod runs with 1:10 ? Is it possible to fix this ? (or am i reading a wrong ratio ?)

I've been using this mod in RSS with lots of tweaks (mostly thrust, weight, and procedural tank dry weight, full weight and volume to match official data), and after a few tries i ended with the same ascent trajectory (slightly falling for the last 15-20%) to orbit Earth with Ariane 5 launcher, that was very interesting.

In my opinion, Hydrolox engines needs to be stock and are clearly indispensable for RSS.

Thanks for this mod ! :)

Edited by xebx
Link to post
Share on other sites
Real LH2/LOx engines (Ariane 5 Vulcain, Delta IV RS-68) runs with mixture ratio 1:6 (and tanks volume ratio is 1:5), why Cryogenic Engines Mod runs with 1:10 ? Is it possible to fix this ? (or am i reading a wrong ratio ?)

I've been using this mod in RSS with lots of tweaks (mostly thrust, weight, and procedural tank dry weight, full weight and volume to match official data), and after a few tries i ended with the same ascent trajectory (slightly falling for the last 15-20%) to orbit Earth with Ariane 5 launcher, that was very interesting.

In my opinion, Hydrolox engines needs to be stock and are clearly indispensable for RSS.

Thanks for this mod ! :)

It is possible to fix this. Go to the CryoEngines folder at GameData, go to parts and pick the .cfg of the one you want. There you can set ISP, Thrust and mass ratio for an engine and the game calculates how much fuel is expended per second.

Link to post
Share on other sites
Real LH2/LOx engines (Ariane 5 Vulcain, Delta IV RS-68) runs with mixture ratio 1:6 (and tanks volume ratio is 1:5), why Cryogenic Engines Mod runs with 1:10 ? Is it possible to fix this ? (or am i reading a wrong ratio ?)

so that's a unit:unit mixture ratio, not a volume mixture ratio. 1 unit of stock Oxidizer occupies more tank space than 1 unit of LqdHydrogen. Look at how many units of Oxidizer and LqdHydrogen a tank holds when it's only holding one resource.

If you want to look under the covers, look over CryoEngines/Patches/CryoEnginesFuelTankSwitcher.cfg, and look over this thread and the Community Resource Pack thread.

The community resource pack settled on a standard volume of 1 unit = 1 liter, vs the ~5 liter/unit volume of stock fuel and oxidizer, but then the LH density was fudged upwards by 50% to compensate for the higher mass fractions dry weight in KSP vs reality.

Edited by billkerbinsky
got something backwards
Link to post
Share on other sites
so that's a unit:unit mixture ratio, not a volume mixture ratio. 1 unit of stock Oxidizer occupies more tank space than 1 unit of LqdHydrogen. Look at how many units of Oxidizer and LqdHydrogen a tank holds when it's only holding one resource.

If you want to look under the covers, look over CryoEngines/Patches/CryoEnginesFuelTankSwitcher.cfg, and look over this thread and the Community Resource Pack thread.

The community resource pack settled on a standard volume of 1 unit = 1 liter, vs the ~5 liter/unit volume of stock fuel and oxidizer, but then the LH density was fudged upwards by 50% to compensate for the higher mass fractions in KSP vs reality.

I don't get this. In KSP these cryogenic engines are very rarely more efficient than LF/LOX engines, usually only good for upper stages (ironic as cryogenics are mostly used at lower stages in real life) and that's because it keeps the upper stages lighter.

Am I missing something? Because if what you say is true and these cryos are more effective than in real life, then how come cryogenic engines are considered better if more expensive?

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...