Realism Overhaul

[asmi]

Make sure you guys update mass for the Soyuz spacecraft itself. BobCat's version is quite a bit heavier than the real thing. In reality it launches to ~200 km @ 51.65°, but not from equator, but Baikonur which is at 46° N.

[Guest]

I've given the spacecraft real mass values for each separate module. Yes, it did place the COM way too forward. I'll have to mess around with offsets to place it where it should be. Oh, and the Soyuz Main Engine is really pathetic. Hardly stronger than it's RCS used to be (now they're even weaker).

EDIT: Also, Nathan, it looks like RemoteTech 1 is no longer available, I don't know if the "lite" version is any good for Gemini. I wanted to include this stuff for Soyuz too, now it looks like a replacement is in order. Oh, and BTW, what plugin does the ejection system? I found it in configs, it looks like realistic Vostok might be doable afterall.

Edited November 3, 2013 by Guest

[asmi]

I've given the spacecraft real mass values for each separate module. Yes, it did place the COM way too forward. I'll have to mess around with offsets to place it where it should be. Oh, and the Soyuz Main Engine is really pathetic. Hardly stronger than it's RCS used to be (now they're even weaker).

That's why 144 m/s dV burn takes over 4 minutes in reality Also on real Soyuz RCS and KDU (main engine) uses same fuel from the same tanks - that allowed designers to get rid of backup main engine - if main engines fails, they can use RCS to deorbit craft.

[NathanKell]

ferram, alas it looks like density is in a linear relationship with pressure.

Dragon01: Yeah, you can put the RT2 SPU on it now, and set the min crew to 0. Then it will work either crewed, or in network.

If you need RT1, you can get my fork here: https://www.dropbox.com/s/16928ut2x37kih8/MyRemoteTech.zip

The ejection plugin is Kreuzung's EVA Parachutes: http://forum.kerbalspaceprogram.com/threads/25305

Re: Soyuz engines. Yeah, Gemini is the same with the OAMS. I mean, technically even the "main engines" aren't, they're just two more of the large RCS thrusters. Even a bit less powerful than the side translation thrusters!

[asmi]

Re: Soyuz engines. Yeah, Gemini is the same with the OAMS. I mean, technically even the "main engines" aren't, they're just two more of the large RCS thrusters. Even a bit less powerful than the side translation thrusters!

Zvezda's "main engines" produce only 23 kN each, and these are used to maintain an orbit of 450 mT vessel, not to mention that Progress' main engine providing whopping 2.95 kN is routinely used for most of ISS maneuvers. Welcome to the world of real spaceflight Nobody here puts 200 kN engine instead of 1kN one just 'cause he isn't patient enough to wait for several minutes-long burn

Edited November 3, 2013 by asmi

[Guest]

Indeed. I really wish we were able to fully simulate the intricacies of various engines. For example, Soyuz main has only 3 throttle settings, with Isp varying as they change. Hmm, maybe the same plugin that does B9 SABREs could be used for that... We also need a better RCS control system, with FAR-style axis assignments, biprop RCS and ability to non-clumsily switch between "fine" and "coarse" systems. Oh, not to mention a bunch of models for real Soyuz RCS. What we have isn't a good replication (though at least it works in KSP).

EDIT: I've also found a potential problem in implementing older Soyuzes (though TM onward and the new Progress are exempt for this, thankfully). Turns out that RCS on the real Soyuz were not balanced at all, and did in fact cause rotation when translating. Igla docking system is a complex piece of machinery which communicated with the docking target, commanding it to make "mirror movements" to counteract this imbalance. This might be difficult to emulate in KSP, to say the least...

Edited November 3, 2013 by Guest

[Miller]

The one thing that I always considered unrealistic in KSP is the need to place some things on the outside of the ship. We should be able to put stuff like computers(mechjeb,kOS,kerbal engineer),batteries and other utilities on the inside of a command pod. A system like that could base on the concept of available volume in the capsule and each items would take some of it up. Just a small idea that I decided to share with you all.

[asmi]

The one thing that I always considered unrealistic in KSP is the need to place some things on the outside of the ship. We should be able to put stuff like computers(mechjeb,kOS,kerbal engineer),batteries and other utilities on the inside of a command pod. A system like that could base on the concept of available volume in the capsule and each items would take some of it up. Just a small idea that I decided to share with you all.

Well technically it's totally possible to do that right now - via adding part modules. We need some sort of GUI for that...

[NathanKell]

Dragon: You can use ModuleHybridEngine for those engines. They work exactly like regular modular engines except you can switch configs in flight. Then you can have the three modes.

[p3asant]

Trying to build a Saturn replica, i tried to calculate the real ones delta V budged. The results made no sense.

Using Tsiolkovsky's equation Saturn first three stages only give 3670 + 3789+2102 delta V.

How can this be so low? 9.4km/s dV barely gets to orbit, not TLI cabable?

I counted the stages followingly:

First : 304*9.81 * ln(3038500/ (2286217-135218)) = 3670

Second: 421*9.81 * ln((3038500-2286217)/((3038500-2286217)-(490778-39048))) = 3789

Third. 421*9.81 *ln((3038500-(2286217+490778))/((3038500-(2286217+490778))-(119900-13300))) = 2162

Weight data from Astronautix.

Any idea what i calculated wrong?

Edited November 3, 2013 by p3asant

[pina_coladas]

Well technically it's totally possible to do that right now - via adding part modules. We need some sort of GUI for that...

The next version of KSP is supposed to have part modules exposed in the VAB scene, meaning the first iteration of "tweakables" should be on its way. This was mentioned in the first daily kerbal. So don't you guys go too nuts making a plugin just yet!

[NathanKell]

I got (m/s dV):

3917.588574

4822.654712

4292.842923

Note that the 3918 is optimistic since you won't get 304s at sea level! It's somewhere between 3918 and 3415.

My method:

for each stage, the wet:dry ratio is stage gross + gross of all stages above it (including the 45ton Apollo stack) / stage dry + gross of all stages above it.

Those numbers are, gross : dry (tons)

2941.923 790.906

655.706 203.976

164.928 58.328

[p3asant]

I got (m/s dV):

3917.588574

4822.654712

4292.842923

Note that the 3918 is optimistic since you won't get 304s at sea level! It's somewhere between 3918 and 3415.

My method:

for each stage, the wet:dry ratio is stage gross + gross of all stages above it (including the 45ton Apollo stack) / stage dry + gross of all stages above it.

Those numbers are, gross : dry (tons)

2941.923 790.906

655.706 203.976

164.928 58.328

Thanks.

Strangely i divided mass full with the amount of fuel in stage.

Now it makes more sense.

Edited November 3, 2013 by p3asant

[Guest]

I'm still running into problems with Soyuz. I've got it to the correct weight (it turned out it was 1 ton too heavy) and used the spreadsheet to get proper fuel loads and burn times. And yet, it's always about 300m/s short of an orbit. Gravity loses are on the order of 1500m/s and I don't think I can get them much further down. Drag and steering are negligible (about 20m/s combined).

I've also noticed a strange thing. While using values directly from the spredsheet, there's a small amount of oxidizer left in tanks after the fuel runs out. Could you check the formula, Nathan? I've got a feeling that something's off.

Edited November 4, 2013 by Guest

[asmi]

I've also noticed a strange thing. While using values directly from the spredsheet, there's a small amount of oxidizer left in tanks after the fuel runs out. Could you check the formula, Nathan? I've got a feeling that something's off.

This does sound a bit fishy.

I'm still running into problems with Soyuz. I've got it to the correct weight (it turned out it was 1 ton too heavy) and used the spreadsheet to get proper fuel loads and burn times. And yet, it's always about 300m/s short of an orbit. Gravity loses are on the order of 1500m/s and I don't think I can get them much further down. Drag and steering are negligible (about 20m/s combined).

Would you please share the config files for them so I could try it out? Soyuz flies on kida unusual trajectory from most of other LVs.

[Photonically]

This is a wonderful project! Huge thanks to NathanKell for making the game feel like proper space flight, not launching toy rockets (as fun as that is)

A couple of things I wouldn't mind seeing on the realism front would be a nerf of the magic reaction wheels (well, I could just turn them down in the configs myself, so it's not really that important), and also of the Kerbals' EVA suit jetpacks (if that's even possible).

Looking forward to whatever Nathan (and other modders) have up their sleeves for the future.

[NathanKell]

Dragon01, I second asmi on posting configs, but just to check--multiply fuel volume by its density (0.0041, I assume) and ox by its ( 0.00571). If you don't get the correct mass ratio, something is off. Also make sure that the ratio of those two volumes really does match what you have in PROPELLANT{} nodes.

Photonically: thanks!

Definitely plan on dealing with reaction wheels; haven't yet looked at how to edit Kerbals...

[ANWRocketMan]

@NathanKell: Have you settled for the sizes/positioning of the smaller bodies yet(Moho - Duna)?

[Guest]

Strange. The Mass Ratio is 2.498, which is correct. Yet, for some reason, there's leftover LOX in the tank. LOX percentage is 0.642, RP-1 is 0.358, straight from the sheet.

Would you please share the config files for them so I could try it out? Soyuz flies on kida unusual trajectory from most of other LVs.

Could you elaborate? I couldn't find any data on the ascent profile. Could you post or link me to some resource that shows how it works? Maybe I'm simply using the wrong ascent profile, it seems that 300m/s could be handled with a more efficient one.

Edited November 4, 2013 by Guest

[NathanKell]

Short of looking at the CFGs myself, all I would suggest is take the amount for LF in the RESOURCE block and copy it directly in the PROPELLANT block on the ratio line so the ratio for LF is exactly the volume of LF. Do the same for LOX.

Then if there's leftover LOX or kerosene, something's deeply bugged.

ANWRocketMan: I currently have all planets in their proper orbits. Moons next. We're still lacking Saturn and Uranus and Neptune and their moons though.

[Guest]

OK, I think I might've found the culprit. Originally, I was using a different, rounded ratio. 0.36 RP-1 to 0.64 LOX. This turned out to be a bad idea, since those numbers add up. It seems that I've forgotten to update them in Modular Fuels part of the config. On the 1st stage booster (test case), I did it the other way around (left the old ratio in stock ModuleEngines, but updated in MF module), and it worked properly. So that should give me some missing dV. Now, just to get that ascent profile.

[NathanKell]

Yeah, the original ModuleEngines stuff gets overwritten by the current MEC Configuration on startup.

[SFJackBauer]

Strange, did the Kerbin rotation period reverted to 6h or its just the map info wrong? The .cfg value seems correct (86164.1)

[Camacha]

Something that has always kind of bothered me about KSP is the wimpy exhaust trail. In real life, rocket launches are partly defined by their exhaust trail splitting the heavens. I understand this is a resources thing, but has anyone ever made any effort to improve the somewhat lacking graphics?

Together with the improved sounds people are working on, I could see some real improvement when it comes to the rather docile stock KSP engines Rocket engines are - and should be - the fury of hell unleashed in a barely controlled manner, not some sparkler going off on new year's eve.

[p3asant]

Something that has always kind of bothered me about KSP is the wimpy exhaust trail. In real life, rocket launches are partly defined by their exhaust trail splitting the heavens. I understand this is a resources thing, but has anyone ever made any effort to improve the somewhat lacking graphics?

Together with the improved sounds people are working on, I could see some real improvement when it comes to the rather docile stock KSP engines Rocket engines are - and should be - the fury of hell unleashed in a barely controlled manner, not some sparkler going off on new year's eve.

Yeah Ksp lacks the "rising to the heavens atop a great pillar of flame" aspect, but is it even possible to draw exhaust longer than 2.5km? I think someone made a mod to alter the physics distance. Then we'd only need better fx, or just cfg edit?

Also it'd be nice to see exhaust variations between engine/fuel types. Delta IV looks like it rises atop red lightsabers and kerolox and srb exhaust all look somewhat different.

Edited November 5, 2013 by p3asant