[1.12.x] Cryogenic Engines: Liquid Hydrogen and Methane Rockets! (Jan 22, 2022)

[abserver]

10 hours ago, Nertea said:

That's... pretty weird. I'll investigate, could you please log an issue with as much data as you have on Github here? https://github.com/ChrisAdderley/CryoTanks/issues

 

Log uploaded . If you need more some help - tell me . More point I forgot to mention in the previous post . If I correctly understood , the fuel leakage begins when I use the maximum warp .

[Kerbonaut257]

So I couldn't find anything on the last couple pages.

What do I do to remove the boiloff? I'm not entirely sure yet whether or not I want to keep that "feature" of these engines

[Nertea]

On 5/25/2016 at 11:13 AM, Kerbonaut257 said:

So I couldn't find anything on the last couple pages.

What do I do to remove the boiloff? I'm not entirely sure yet whether or not I want to keep that "feature" of these engines

Delete simpleBoiloff.dll from the plugins dir. I'll include a patch in the next version I think.

On 5/23/2016 at 10:18 PM, abserver said:

 

Log uploaded . If you need more some help - tell me . More point I forgot to mention in the previous post . If I correctly understood , the fuel leakage begins when I use the maximum warp .

Aha, didn't notice that maximum warp thing. In that case, if you happen to have the craft file... that would be great. It's hard to repro this one reliably. 

[Kerbonaut257]

Just now, Nertea said:

Delete simpleBoiloff.dll from the plugins dir. I'll include a patch in the next version I think.

Aha, didn't notice that maximum warp thing. In that case, if you happen to have the craft file... that would be great. It's hard to repro this one reliably. 

Thanks!

I really like this mod. I might tweak the boiloff numbers slightly, I assume I can do that in simpleboiloff.dll? I'm at work so can't see it. But I am looking forward to using some cool alien-looking spherical ships with high delta-v

[Nertea]

1 minute ago, Kerbonaut257 said:

Thanks!

I really like this mod. I might tweak the boiloff numbers slightly, I assume I can do that in simpleboiloff.dll? I'm at work so can't see it. But I am looking forward to using some cool alien-looking spherical ships with high delta-v

Nah, that's to delete all the boiloff stuff. To edit the rates, go to GameData/CryoTanks/Patches/CryoTanksFuelSwitcher and edit the patches there. There will be two entries, one under ///Lifting Tanks, for the tanks that don't have cooling, and one under ///ZBO Tanks. Look for ModuleCryoTank:

MODULE
{
	name =  ModuleCryoTank
	FuelName = LqdHydrogen
	// in % per hr
	BoiloffRate = 0.05
}

Edit the BoiloffRate to change the rate, it's in % per hour, so the example about boils off 0.05% of the tank per hour. For the ZBOTanks, edit CoolingCost (in Ec per 1000u per second) to change the cooling cost.

As an alternative to deleting SimpleBoiloff.dll, you could also delete both these MODULE blocks.

[Kerbonaut257]

5 minutes ago, Nertea said:

Nah, that's to delete all the boiloff stuff. To edit the rates, go to GameData/CryoTanks/Patches/CryoTanksFuelSwitcher and edit the patches there. There will be two entries, one under ///Lifting Tanks, for the tanks that don't have cooling, and one under ///ZBO Tanks. Look for ModuleCryoTank:

MODULE
{
	name =  ModuleCryoTank
	FuelName = LqdHydrogen
	// in % per hr
	BoiloffRate = 0.05
}

Edit the BoiloffRate to change the rate, it's in % per hour, so the example about boils off 0.05% of the tank per hour. For the ZBOTanks, edit CoolingCost (in Ec per 1000u per second) to change the cooling cost.

As an alternative to deleting SimpleBoiloff.dll, you could also delete both these MODULE blocks.

Okay awesome! Thanks. 

So I could make the electrical usage cheaper by decreasing cooling cost on the tanks, or make the boiloff less on the non cryo tanks? Seems good. I still haven't really had a chance to use the mod yet so I'll try it your way and then rebalance it if I get annoyed

[Gordon Dry]

I deleted the simpleBoiloff.dll but still got boiloff, during launch my yet-unused LqdHydrogen procedural tanks are already dumping ... ?

[BashGordon33]

I noticed in each size pair there is an engine with high isp and an engine with low isp but better thrust. Could you please make the high isp engine lower profile. The High Isp regular engines are all short and fit nicely into the rocket. Good upper-stage engines are always low profile. Just a suggestion for a future update. Ether that or add 3 new low profile engines that run off hydrogen. 

Edited May 29, 2016 by BashGordon33

[blowfish]

1 hour ago, BashGordon33 said:

Good upper-stage engines are always low profile

In Stock KSP maybe ... in real live almost never.  Good vacuum efficiency requires having a very long nozzle to expand the exhaust as much as possible.

Anyway, what's so bad about having a rocket a couple of meters taller?

[ChainiaC]

I think I understand: landers. Last night I landed on Duna with a Chelyabinsk. I had to land very softly on the engine bell, quickly deactivate the engine so the lander didn't topple over, and then had it sit on it's lander legs. Taking off was the same but in reverse: Activate engine and burn like hell before I fall over. But that's ok, I understand the reason for the long nozzle. I'll happily deal with that in return for the ISP. Besides, thanks to deployable engines This nice workaround was possible.

On a related note, I for one really like the extra realism and design consideration that comes with hydrogen boiloff. Great feature! I kept the hydrogen for the lander in the nuclear transfer vehicle's cryotanks for the journey and pumped it over when in Duna orbit.

Edited May 29, 2016 by ChainiaC
typo

[BashGordon33]

1 hour ago, blowfish said:

In Stock KSP maybe ... in real live almost never.  Good vacuum efficiency requires having a very long nozzle to expand the exhaust as much as possible.

Anyway, what's so bad about having a rocket a couple of meters taller?

One word: Landers. I desperately want to use one of those awesome engines for a lander, but their too tall to land with. And I know RL upper stages are long, but relatively to the boosters they are smaller. You probably are right about not changing the 3 higher ISP rockets, but maybe a similar ISP low profile rocket could be made for the next update

[ChainiaC]

29 minutes ago, BashGordon33 said:

One word: Landers. I desperately want to use one of those awesome engines for a lander, but their too tall to land with. And I know RL upper stages are long, but relatively to the boosters they are smaller. You probably are right about not changing the 3 higher ISP rockets, but maybe a similar ISP low profile rocket could be made for the next update

Well you could build out the landing legs with trusses. You would have to do the same if you'd want to land with a stock LV-N. I have done that in the past. Or you could use the undeploy/deploy maneuver I described, or use infernal robotics, or use lithobraking technologies' enormous landing legs... many stock and mod options

Edited May 29, 2016 by ChainiaC
typo

[BashGordon33]

22 hours ago, ChainiaC said:

Well you could build out the landing legs with trusses. You would have to do the same if you'd want to land with a stock LV-N. I have done that in the past. Or you could use the undeploy/deploy maneuver I described, or use infernal robotics, or use lithobraking technologies' enormous landing legs... many stock and mod options

I have considered this, and I really don't thing long legs will work. A lander should always be wider than it is tall, to make it harder to tip over. I made that mistake on my first lander. I will never mention what happened again. I'm not asking for a change of engines, but low profile engines would make the mod feel more complete. And Infernal Robotics has never worked for me

Edited May 30, 2016 by BashGordon33

[ChainiaC]

40 minutes ago, BashGordon33 said:

I have considered this, and I really don't thing long legs will work. A lander should always be wider than it is tall, to make it harder to tip over. I made that mistake on my first lander. I will never mention what happened again. I'm not asking for a change of engines, but low profile engines would make the mod feel more complete. And Infernal Robotics has never worked for me

I understand. I prefer the shortest possible engine for a lander all other things being equal. The problem here is that these engines are based off of real physics. In that case the longer the nozzle, the better the engine efficiency/ISP in vacuum. If you shorten the nozzle, it underexpands the exhaust and you lose more energy by gas being vented sideways providing no thrust to your vessel. So short nozzle automatically means less ISP I'm affraid. 

Maybe if there was a tiny size engine the nozzle could be long in relation to the engine but still be short in relation to the overall vessel or you could mount several of them radially to reduce the length of your lander.

Oh yeah, and I am neither a rocket scientist nor a physicist, so what I explained might be wrong or oversimplified, but I read this forum, wikipedia and atomic rockets and I play KSP, so that's my sources

Edited May 30, 2016 by ChainiaC
typo

[Drew Kerman]

10 hours ago, ChainiaC said:

Oh yeah, and I am neither a rocket scientist nor a physicist, so what I explained might be wrong or oversimplified...

Nah you did good. But just in case there are still any doubters Scott Manley will convince them:

 

Edited May 30, 2016 by Gaiiden

[BashGordon33]

On 30/05/2016 at 2:27 PM, ChainiaC said:

I understand. I prefer the shortest possible engine for a lander all other things being equal. The problem here is that these engines are based off of real physics. In that case the longer the nozzle, the better the engine efficiency/ISP in vacuum. If you shorten the nozzle, it underexpands the exhaust and you lose more energy by gas being vented sideways providing no thrust to your vessel. So short nozzle automatically means less ISP I'm affraid. 

Maybe if there was a tiny size engine the nozzle could be long in relation to the engine but still be short in relation to the overall vessel or you could mount several of them radially to reduce the length of your lander.

Oh yeah, and I am neither a rocket scientist nor a physicist, so what I explained might be wrong or oversimplified, but I read this forum, wikipedia and atomic rockets and I play KSP, so that's my sources

You are right about the nozzle length. I know high efficiency rockets require long nozzles. I never requested a high efficiency low-profile engine. Here's an idea, the engines can fire without the nozzles extending at the cost of ISP. 

[Gordon Dry]

Is it normal that the rate of boiloff loss increases as the tank's content decreases?

[Kerbonaut257]

On 5/27/2016 at 10:08 AM, Nertea said:

Delete simpleBoiloff.dll from the plugins dir. I'll include a patch in the next version I think.

Aha, didn't notice that maximum warp thing. In that case, if you happen to have the craft file... that would be great. It's hard to repro this one reliably. 

Umm. I can't get rid of boiloff. I deleted the .dll AND i removed those module parts where the boiloff rate is set and the EC cost is set. I can't seem to get rid of it :/

[SciMan]

There might be a different kind of way to get around this "high ISP engines = long" problem.

Lots of little nozzles, instead of one big nozzle.
RD-170 style instead of F-1 style (kerolox engines, but I'm focusing on the nozzles not the propellants).

The Russian Glushko RD-170 is a single engine that has multiple rocket nozzles, but a common turbopump.
The American Rocketdyne F-1 is a single engine that has a single very large rocket nozzle.
The specifications of both engines are roughly comparable. However, the F-1 is notably longer.

RD-170: 3.78m length x 4.02m diameter
F-1: 5.64m length x 3.72m diameter
Source: Astronautix.com

So if you have a single engine that has a bunch of smaller nozzles, but each of those nozzles still has a pretty good expansion ratio.
The result is a short engine of large diameter that does not sacrifice ISP for compactness, at the cost of being more complex.

I do not know of any Lox/LH2 engine IRL that has a form factor like what I'm thinking of (likely because of the complexity of the plumbing), but that doesn't stop someone from making one in KSP.

[Gordon Dry]

So never build an interplanetary science probe that uses LqdHydrogen in any way - fuel is gone after a couple of weeks.

And as I said and as Kerbonaut257 said, deleting the .dll and/or deleting the modules doesn't stop the boiloff... so where is it hidden?
If the SimpleBoiloff.dll would be used by KSP then I could not rename it to SimpleBoiloff.dll.disabled runtime, right?

Spoiler

I scrapped the LqdHydrogen stage on my vessel that initially got 60,000 m/s and is a millstone around my neck after nearly 3 months in which a couple of short burn maneuvers were done...

Now my XenonGas stage with 115,000 m/s but way less TWR has to finish the job - still in earth SoI - damnit ...

bye, bye, stage

Now I go solo, no more pushing my back

I know, it's not perfect, it's still a testing probe

 

Edited June 2, 2016 by Gordon Dry

[SciMan]

Well, you've eliminated SimpleBoiloff.dll as a suspect for the cause of your problem.

I think the fastest way to find the cause would be to hit Alt-F12.

Alt-F12 is not just for cheating. It's much better (IMO) for figuring out what the part configs look like after the MM patches have been applied.

I'd say your best bet would be to hit Alt-F12 in game, go to the "configs" tab, un-tick all the buttons except for "parts" and then look thru your hydrogen tanks to see what modules you can see.

Post up whatever part module names you think are related, somebody will probably be able to tell you what plugin it's from.

 

Could be KSPI-E or Real Fuels if it's not one of Nertea's plugins doing this to you.

[Gordon Dry]

You could be right, but if another mod does so, it does it only when Cryogenic Engines is found.

I was doing some searches through all .cfg files in GameData about the terms boiloff, boil off, fuelflow, fuel flow and loss - nothing found that points in any direction.

So I'll try what you suggested.

[Kerbonaut257]

2 hours ago, Gordon Dry said:

You could be right, but if another mod does so, it does it only when Cryogenic Engines is found.

I was doing some searches through all .cfg files in GameData about the terms boiloff, boil off, fuelflow, fuel flow and loss - nothing found that points in any direction.

So I'll try what you suggested.

Yeah I'm at work but I'll try this when I get home. It obviously has to be another mod because I've looked in every single part of the cryo tanks and cry engines folders and there's nothing related to boiloff left, I deleted it all.

 

EDIT: Also worth noting is that if I have 3 tanks with the same fuel type stacked, the boiloff happens at DIFFERENT RATES. The boiloff being the most severe in the middle tank. And after deleting the boiloff stuff from the actual cryo tanks mod, the boiloff rate is EVEN FASTER. It's like insanely fast. Probably 1  percent per second or so from the middle tank in the stack.

Edited June 2, 2016 by Kerbonaut257

[Gordon Dry]

I also recognized that the boiloff rate increases during time.

Using the HI-530 it started with 0.6/s, now, after 2 hours in orbit, it's 1.12/s

[Nertea]

Logs are very helpful. All I can say right now is that if you delete the dll, there is literally no code to remove the fuel, so... yeah.

Edited June 2, 2016 by Nertea