The Lone Wolfling

Nice way around the density issues. Something spinning at a constant speed shouldn't provide any torque, unless you're talking about gyroscopic effects? Same. Even without the mass issues boiloff makes LH2 useless for later stages, which is rather contrary to the intended purpose.

Did you change the minimum arrival time?

Agreed, unfortunately. The issue is that as the size increased the advantage swings towards the fuel with the higher mass ratio asymptotically, which means that in order to get the very large mass case right it means that at small sizes the lighter fuels are much better than the denser fuels. It looks like I'm going to next try reducing dry tank weight instead and seeing if that helps. Moment. I cannot reproduce. What are you using to calculate delta-v? Are you sure that you removed the same amount of LF and OX from the tank? Are you sure that the tank fuel flow is correct? Can you show pictures / a craft file?

Here is my first attempt at a MFT config pack that makes other configs besides LF/OX actually useful. It only has the squad parts, and it still needs a bunch of tweaking (in particular I should scale the atmospheric Isps by the ratio of the old vacuum Isp to the new vacuum Isp instead of using the scaling of LF/OX), but I might as well get other eyes on it.

Does it? Because the numbers I get in-game match with the numbers I get by manually calculating the mass ratio. Nope. The engine calculates a mass flow rate and backtracks that to propellant amounts based on the ratio of the fuels. It's burning the "right" amount, AFAIK. They are high I believe- see here. ~286s at sea level. Yes it could, but then you're making it fall out of line with stock. Again, even assuming an infinite mass of fuel tanks (or equivalently payload + engine weight = 0) it's still not worth it currently. Huh. I've seen the H2 mass ratio quoted as higher for tug designs, but those don't need to hold up under 1G. Although that being said I wouldn't apply IRL physics to KSP - the dense planets / atmospheres throws everything off. Square-cube law, in other words. Perhaps what we need is to scale tank internal volumes to assume a thickness of tank wall proportional to the radius?

Hmm... It would certainly have the advantage of not changing stock equivalents at all. Let's see. The LV-909 has a specific impulse in LF/OX mode of 370. It would have to have a LF/LOX Isp of at least 526(!) to be worth it, and a H2/LOX Isp of at least 648(!). The NERVA would have to have an Isp of >1030(!!) to be worth it. It would be doable, as long as people didn't complain about the unrealistic values. Want me to whip up a temporary set of config files to test? Thought about this, but the dry tank mass would have to be so low... Not to mention that cryogenic fuels tend to require more tank mass, due to the amount of insulation required.

Yep. Yep again. I've tried doing that locally, and it breaks the game, or rather it makes it much much much easier to get anywhere to the point where you don't need the NERVAs anyways. You hit the decreased size of the planets, in other words.

Alright. So, the problem with the LV-N (and LOX/LH2 in general) is that the tank mass ratio is too low for it to make sense to use it. Yes it would increase the delta v, but even if the mass of the NERVA was the same as the LV-45, it still isn't worth it. Wrong. IRL mass ratios are much higher. Wrong again. We know how much fuel a NERVA would need as we've conducted tests. Not to mention that it's pretty easy to calculate approximate exhaust velocities of a purely thermal rocket, all things considered. Correct in KSP. IRL, again, the mass ratios are higher and as such the LV-N does make sense in delta-v terms. ...A couple posts back I did the math for an infinite mass ship, and it still doesn't make sense to use a LV-N. Something needs to be done about the LV-N. Currently with the real fuels it is never worth it to use a LV-N.

See here. Don't compare apples to oranges - the LV-T45 is a good lower stage rocket for smaller rockets, but isn't designed for efficiency like the NERVA is. If you want efficiency, you want the LV-909 to compare it to. A NERVA is ALWAYS worse than a LV-909 with a single stage, assuming I've got my math right from the previous post. And with a LV-909 it is ALWAYS better to use LF/OX with a single stage. I did quite a post about this and got basically no response. The issue is the decreased mass ratio when you go with less dense fuels - the tank dry mass is way too high for the less dense fuels to make sense. IRL, tank mass ratios are way higher (more fuel per mass of tank), which is why it makes sense IRL but not in KSP.

Agreed. My two most wanted parts would be control surfaces and landing gear / wheels, though. Most everything else you can simulate with other parts.

It's about the same, which is to say that hauling unrefined fuel is probably slightly more efficient as you don't need to haul along a converter.

Glad to see that. I believe we're talking about scene transitions though, if Benie is talking about the same thing I am. From <5s from VAB to launch in 0.20 to >15 in 0.21, and growing. And SOI transitions also have pauses.

They are... Press r and mouse over the fairing.

Try adding the resource you want to the part, along with ManagedResources. Look in the part.cfg

Yes, it's not just you. Unfortunately, it has been confirmed as not being re-added.

Sorry. I read back to page 127 and didn't see it. Looks like I was just short. Could you add that (the disclaimer that it will break save compatibility) to the main post, please? Ok. Looks like I won't be using it then. Too bad, I like the mod.

Hmm... I'm sure this has been mentioned before, but I have a suggestion: procedural control surfaces.

Two semi-related questions: Currently RT2 is only for testing. Any idea of how long until it will be properly released? Even an order of magnitude would be nice. (Minutes, hours, days, weeks, months...) Second, will RT2 be compatible with RT1? I'm looking into starting a "KSP Hard-mode" game, one that will be long-running, as usual for me (I've had... 3? saves so far), and wondering if I should a) wait for RT2, use RT1, or c) don't use RT at all. Also, a suggestion: would it be possible to auto-assign free antennas? i.e. if a loaded vessel would be without control, search through any vessels that currently have control and have free antenna(s)/dish(es) and automatically try to connect with the vessel.

I just had this issue today on a stock 0.21.1 install. Lost the bottom node of my command pod. Non-reproducible though.

So, some thoughts. Assuming a single stage throughout, and in vacuum. LF = Liquid Fuel, OX = Oxidizer, LOX = Liquid O2, H2 = Liquid H2 The mass ratio of LF/OX is ~46.32. The natural log of this is ~3.84. The mass ratio of LF/LOX is ~14.73. The natural log of this is ~2.69. The mass ratio of H2/LOX is ~8.940. The natural log of this is ~2.19. Delta-v is Evel*ln(Mf/Mi). In the limit, Mf/Mi is equal to the tank mass ratio. As such, the maximum delta-v attainable by a single stage is equal to ln(TMR) * Isp * G. So, let's look at the LV-909 for a moment. Its Isp with LF/OX is 370. 370*3.84*9.82 = 14000m/s. Its Isp with LF/LOX is 390. 390*2.69*9.82 = 10300m/s. Its Isp with H2/LOX is 460. 460*2.19*9.82 = 9890m/s. So, for a single stage with the LV-909, always use liquid fuel / oxidizer. The mass ratio decrease more than kills the increase in specific impulse. Is this intended? To quantify that for other engines, just divide the logs. An engine has to have a specific impulse in LF/LOX mode of at least 1.42x of LF/OX mode to be worth it. An engine has to have a specific impulse in H2/LOX mode of at least 1.75x of LF/OX mode to be worth it. An engine has to have a specific impulse in H2/LOX mode of at least 1.23x of LF/LOX mode to be worth it. Again, assuming a single stage. With multiple stages it might be worth it, I don't know though. Next, let's look at how to extend this to multiple stages. Assuming that the decoupler weight is negligible, you can have an infinite number of decouplers and infinitely small fuel tanks, and as such carry no extra tank mass at any point. Effectively, you're also burning the dry mass of the fuel tanks with zero specific impulse. When you work out the fuel usage equation, this works out to an effective specific impulse of Isp / (1 + 1 / mass ratio). Math follows: Ispeff = sum(thrusts) / sum(mass flow rates) Ispeff = thrust / (thrust / Isp + 1 / (mass ratio) * thrust / Isp) Ispeff = 1 / (1 / Isp + (1 / (mass ratio)) / Isp) Ispeff = Isp / (1 + (1 / (mass ratio))) Now, as to how to compare rockets. Isp1 / (1 + 1 / TMR1) > Isp2 / (1 + 1 / TMR2) Isp1 / Isp2 > (1 + 1 / TMR2) / (1 + 1 / TMR1) As such, the following applies in multistage mode. An engine has to have a specific impulse in LF/LOX mode of at least 1.05x of LF/OX mode to be worth it. An engine has to have a specific impulse in H2/LOX mode of at least 1.09x of LF/OX mode to be worth it. An engine has to have a specific impulse in H2/LOX mode of at least 1.04x of LF/LOX mode to be worth it. So now lets compare the LV-909 and the LV-N. The mass ratio of H2 is ~3.970. The natural log of this is ~1.38. Its Isp is 850. 850*1.38*9.82 = 11500 m/s. In other words, it is always more efficient with a single stage to use a LV-909 (in LF/OX mode, none the less!) than a LV-N. At 2.33 tons, a LV-909 has ~2670 m/s of delta-v while the LV-N has 0, and it never catches up. ...is this intended?

The symmetry and snapping icons appear even when you have the astronaut panel open. Other than that, seems to work fine on 0.21

You're forgetting about the radius of Kerbin itself.

If/when you do this, please make sure you've fixed both the jet issue (jets producing way more thrust than they should at sea level) and the SABRE issue (SABREs produce a wonky amount of thrust when they switch modes). It would also be nice to be able to toggle between atmospheric mode and vacumn mode for the amount of thrust produced i the ModuleEngines for use with MechJeb / KE Redux for thrust-to-weight ratios.

Which is why all mod authors (that I know of at least) include the dll in the root gamedata directory. Only one copy is loaded. B.S.. I quote: Not to mention the following:

Why? (10char)