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[1.1.2] Realism Overhaul v11.0.0 May 8


Felger

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Alright, trying this out and I have run into some issues with the FASA Saturn V craft.

(removed after reading release notes)

- Did a re-entry with the Apollo CM from a 4681km x 76km orbit and only used 3 units if the ablator and maxed out the gforce gauge so I suspect that something is not right somewhere. If my periapsis needs adjussting I can understand but that gforce does seem to be to high as I expect my Kerbals would have died if DRE was installed. I would have had a much higher apoapsis but ...

- I am having troubles with restarting the J2 on the S-IVB stage. It starts fine after separating the lower stages and I can circularize my orbit without a problem but I am having problems when I go to perform the Lunar insertion burn, I cannot get the fuel flow to stablize. Any suggestions here would be nice. Firing the RCS works to restart the SPS but not the J2 and so I am a bit stuck.

Edit: Think I might have found the proper solution to the ullage. Will be trying again. Any thoughts and advice on the re-entry is welcome as I do not know where to begin for this one.

Edited by smartdummies
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Noticing something weird with the RS-68 engines.

Not sure of it's my install, but the engines work, but there is no gimbal animation, even though the flame exhaust is clearly vectoring and the rocket turning.

And I noticed there is no launch smoke. Is that expected with real plume?

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I have the same problem with real plume, every second games pauses for like a quater to half of a second -> unplayable by my standarts

3.2gb ram usage, i5 [email protected], nV 970, fps is good and mission time is green (except when its pausing, then it's yellow)

i tried physics delta at 0.12sec, but it was no good

how do you open smoke screen tool ingame?

Install blizzy's toolbar, and add the smokescreen button to it. I wonder what's causing the pausing, I haven't seen anything like that in my testing, if anything it should be a constant fps hit.

Noticing something weird with the RS-68 engines.

Not sure of it's my install, but the engines work, but there is no gimbal animation, even though the flame exhaust is clearly vectoring and the rocket turning.

And I noticed there is no launch smoke. Is that expected with real plume?

At the moment, several effects have no visible smoked, for a couple reasons. First, the real life versions produce either very little or no visible smoke. Second, smoke has a lot of particles, which can be a fairly substantial performance hit.

Those two coupled is why I've decided to leave them off until I can get a polished version out.

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As to upper stages: yep, working as designed, you either need ullage motors or you need to hot-stage, just like real life. :)

In fact, hot staging is nothing else than using an ullage motor. A very, very large ullage motor... :cool:

Generally RCS won't be useful except for small stages (though the sim will need tuning for stage size). How big a stage are we talking about?
According to wikipedia, only 0.001g is needed to avoid ullaging of the fuel. Seperation motors should do the trick.

I will (may?) have a flameout, when tank content drops below 10%. Right? MechJeb thinks that the stage isn't empty, so it won't activate the next stage. Similar problem with ullage motor. I have to start ullage motor FIRST, and with enough thrust given, main engine SECOND. I cannot start them at the same time. And I have to take care to start the main engine before I the ullage motor goes out. That means: No chance of automatisation (as in real life) but high chance of failure.

Currently I am quite unsure wether it will add spice to my playing or frustration...

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I'm a bit at a loss. Do real rockets really work that way? If yes, how does an Aestus 2 restart it's engines, considering it's a full blown, if small, upper stage? That things has 15 ignitions! Or the moon lander, which had seperate burns. Latter two use hypergolic fuels, which afaik are easier to restart (yeah i know they still need some kind of ullage)? Doesn't seem to be simlated, tho...

Also, is there some way to restock ignitions for multi-use craft, e.g. with KAS? Or is it just a theoretical design limit (in which case it should be risky, but possible too ignore the limit :D)?

While I'm also a bit skeptical about the whole thing, i'm curious about the challenge. Just hoping it'll be one that's possible to overcome.

edit: Seems like the ignition automatically kills engines after reloading?

Edited by Temeter
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As to upper stages: yep, working as designed, you either need ullage motors or you need to hot-stage, just like real life. :)

Generally RCS won't be useful except for small stages (though the sim will need tuning for stage size). How big a stage are we talking about?

I had a look at the source on github, it seems that there is no 'fade off' in the ullage simulation so the next Update() after acceleration drops to zero it'll transition straight to very unstable. If you had a DLL with the debug sections compiled I'd be happy to run a few tests. The RCS is 3.2 kN for a 22t full stage, 1.2 kN for a 5t full stage - not a huge TWR but it should be sufficient to settle things.

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Thanks to everyone who worked on ullage and limited ignitions in RF. These are essential features for me. It was the thing that made engine choices and flight planning the most interesting compared to the base game, and the main thing that added difficulty in RO/RSS. I just want to report that the ullage seems fine and very similar to past versions.

I can settle a 10 ton stage with 4 RV-105-45s producing 255 newtons apiece. I have done it in a low suborbital situation and I just tested it in what seems like worse cases to me. First, on the way up in the upper atmosphere, soon after it became fully unstable. And second, just as it reached apoapsis at 14.5km, while tumbling. (Has to be less than 255 newtons at that altitude.) It seems pretty fair to me.

Craft file if it happens to work in your install: https://www.dropbox.com/s/4ce496ska8co4mt/Orbit.craft?dl=0

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Am I right in my assumption that 'service module' tank configs are the ones that actively preserve the pressure? That should solve some problems, might make some nice starter engines...

edit: No, doesn't work either. Still learning, but personally can't really say I'm enjoying the Ullage system. How does an Ariane upper stage then deal with multiple ignitions?

Edited by Temeter
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I tried the Laztek SpaceX launch pack and the exhaust from the Merlin 1Ds seems to come out inside the engine. (I also get a lot of different nullrefs in the log)

Pic:

EZWZ9BS.png

Edited by kendoka15
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Am I right in my assumption that 'service module' tank configs are the ones that actively preserve the pressure? That should solve some problems, might make some nice starter engines...

edit: No, doesn't work either. Still learning, but personally can't really say I'm enjoying the Ullage system. How does an Ariane upper stage then deal with multiple ignitions?

I tried restarting the aestus II a few times using RCS like I described above. Everything seemed to be working fine for me. Turn on RCS, push 'H' for a few seconds, until the fuel reports as "very stable" and then activate the engine. The model I am using looks like it's coming out of RLA stockalike, for what's it worth. (As Nathan so patiently explains, the pressure level of the tank has very little to nothing to do with the gas mixed into the fuel. Ullage motors stand in place for gravity, not pressure.)

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Temeter: I have experienced no trouble restarting Aestus II stages with some RCS ullaging. Similar approach works for LM (and CSM).

Engine Ignitor supported external (KAS) ignitors. I'll add that to RF eventually, just haven't had a chance yet.

What do you mean by "Seems like the ignition automatically kills engines after reloading" ?

Ratzap: where are you seeing that? I'm looking at the venting section (where natural diffusion is done), and it lerps between present value and fully-diffused value using a lerp of 0.00112 per tick when the tank is full.

That's

1 / (.5 + fuelRatio [1 when full]) / 1.4) * 0.02 [fixedDeltaTime] * 0.06 [diffusionRate]

Sure I can make a debug version though.

Temeter: What do you mean by "actively preserve the pressure"? See above for why pressure has nothing to do with ullage.

kendoka15: Issue with the smokescreen released yesterday. Check the SmokeScreen thread.

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T

Ratzap: where are you seeing that? I'm looking at the venting section (where natural diffusion is done), and it lerps between present value and fully-diffused value using a lerp of 0.00112 per tick when the tank is full.

That's

1 / (.5 + fuelRatio [1 when full]) / 1.4) * 0.02 [fixedDeltaTime] * 0.06 [diffusionRate]

But that is wrapped by

if (ventingAcc <= RFSettings.Instance.ventingAccThreshold)

If there's no boil off venting, it'll just work out the current acceleration and then switch states no? What I would have in there is something like a configurable minimum length of time in a state. So if you reach very stable you should at the very least get fuelRatio x statechangeConstSeconds before it can switch down another notch. Ie prevent jumping from very stable to very unstable in a couple of updates.

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Do you have the latest smokescreen? That looks like a bug I caused in the previous version.

Updating fixed it. Thanks a bunch :) (CKAN doesn't apparently have the latest smokescreen right now)

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Temeter: I have experienced no trouble restarting Aestus II stages with some RCS ullaging. Similar approach works for LM (and CSM).

Engine Ignitor supported external (KAS) ignitors. I'll add that to RF eventually, just haven't had a chance yet.

What do you mean by "Seems like the ignition automatically kills engines after reloading" ?

On reloading all engines instantly shut down (flameout), which basically left my rockets stranded during experimentation. After that I also had some issue with figuring out RCS tanks, which made testing even harder, until I remembered and checked the service-module tank. Was just a bit frustrating until I figured out the details (especially considering getting into space takes a bit longer anyway). More optimistic now.

edit: Jep, now it works. Made a mistake staging my rockets upper stage (120T), and managed to ignite it via RCS. Guess Forward RCS is just more important now. Much better now, I like challenges when I can understand the rules. :D

External Ignitors would be awesome!

Temeter: What do you mean by "actively preserve the pressure"? See above for why pressure has nothing to do with ullage.

kendoka15: Issue with the smokescreen released yesterday. Check the SmokeScreen thread.

Just wrong terminology, I ment the fuel pushing against whatever place its needs to be for ignition.^^

Edited by Temeter
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you need to hot-stage, just like real life. :)

trying to hot-stage but im finding that when using the procedural fairings inter stage fairing i get the message of "unable to deploy *engine name here* when stowed" quite an annoying addition by one of the 1.0 updates from squad.

I know its not an issue with RO, but I was thinking someone here may have a workaround or an alternative so that I can successfully hot stage? either that or ill just revert to ullage for every god damn stage

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trying to hot-stage but im finding that when using the procedural fairings inter stage fairing i get the message of "unable to deploy *engine name here* when stowed" quite an annoying addition by one of the 1.0 updates from squad.

I know its not an issue with RO, but I was thinking someone here may have a workaround or an alternative so that I can successfully hot stage? either that or ill just revert to ullage for every god damn stage

If you use the fairings rather than the structural pieces and stage them off first, the engine will deploy. It takes hitting two stages at the right time, but the margins in RSS/RO really aren't as bad as some people think so a little wasted fuel here and there won't kill you. I think a little bit of waste happens in things like staging events in real life too. Sometimes it's more important that something works than you scrape every last foot per second out of a stage.

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Ratzap: That means, if the venting acceleration from boiloff is > the threshold, no diffusion at all takes place. If it's <= threshold, then the diffusion is proportional to 1- acc/threshold (which will be 1 when there is no venting accel from boiloff at all).

Even if it's 1 (no venting at all), as I showed above the value used in the lerp is small. The formula I gave is what it uses when there's no venting at all, and you can see the result is only a lerp factor of 0.00112. If you want to change how slowly the propellants diffuse to fully diffused, lower the naturaldiffusion factors.

Temeter: I wasn't aware you could save with engines running (i.e. providing acceleration). If you throttle back an engine to "zero thrust" that _is_ turning it off. :)

What docs would have made your life easier? It sounds like we need more docs. :) And awesome! :D

Mitchbra: SolverEngines should have fixed that issue. What engine(s) are you getting that message from? (Can't ignite while shielded)

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I have only had time to test the RD 146 from the soviet engines pack, I can test some more when I come back from work if needed, my solver engines is definitely installed and up to date according to CKAN

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Does real plumes currently only have cfg for FASA engines or is KW rocketry also supported? I would like to only use real plume supported engines right now and aside from FASA Im not sure what other engine packs are supported.

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