[1.0.2] Kerbol 3.7 - Stock system re-scaled x3.7 (A Kopernicus-based mod)

[Streetwind]

At this time, terrain max altitudes have not changed and thus don't require the space/low, space/high etc to be adjusted.

I have not changed atmospheres yet as they would only change by a few km. Assuming that a x10 scaled Kerbin has the exact same qualities of Earth, Kerbin at x3.7 only has an atmosphere height increase of about 11km. Though I guess a 15% increase is non-trivial so if that is something you would like, I can make the changes in the next update.

Here's the relevant post for un-changed atmospheres, for reference.

Though, Eudae55: a 10x scaled Kerbin is not identical to Earth. To be identical, it would have to be 11x scaled. Just a minor nitpick But the 11km number you quoted isn't a bad choice at all, to be honest. Considering Kerbin's atmosphere starts between 69km and 70km in stock, that means you could simply set it to 80km and have a nice round number that's fitting at the same time.

Greatly looking forward to experiment further with this mod. At first I thought it would be borderline too large to play with stock parts and would have preferred more like 3.0x, but I just tested it and it's not as bad as I thought it would be. Different, but doable. Well, at least with the small rockets I tried If this eventually ships with (or fits together with) rescaled OPM planets, that would be fantastic.

[Bomoo]

Very well. If not 3.7x atmospheres, how about 2x? Does stock atmosphere height with 3.7x planets not seem excessively low to anyone else?

[Wiseman]

Earth's Karman line (the boundary between atmosphere and space) is around 100km, and it's 11x the size of Kerbin. So, stock atmosphere is high, if anything.

[Bomoo]

Earth's Karman line (the boundary between atmosphere and space) is around 100km, and it's 11x the size of Kerbin. So, stock atmosphere is high, if anything.

Fair point. Though I'd have liked it at, at least, 1.5x atmosphere height. Ah well.

[Bomoo]

You know what, I take that back. Atmosphere feels fine at 70km on a 3.7x upscale. However, do yourselves a favour and edit the cfgs of your heatshields to jack up the amount of ablator resource. My Mk1-2 pod went boom after ripping through 800 ablator in about ten seconds during a gentle 30km Pe reentry from a 190km orbit.

[NathanKell]

Or turn down some of the physics settings.

Indeed, I'd suggest bundling an MM patch to reduce some convective settings--here's how RO changes things if you want to see an example.

https://raw.githubusercontent.com/KSP-RO/RealismOverhaul/master/GameData/RealismOverhaul/RO_Physics.cfg

[Streetwind]

Or turn down some of the physics settings.

Indeed, I'd suggest bundling an MM patch to reduce some convective settings--here's how RO changes things if you want to see an example.

https://raw.githubusercontent.com/KSP-RO/RealismOverhaul/master/GameData/RealismOverhaul/RO_Physics.cfg

What's the process you followed to come up with those values? Did you trial and error until it felt right, or did you use some sort of calculation? That's a huge number of constants, and I've no idea what the stock defaults are for them, or how adjusting them affects the game... unfortunately looking at that file tells me absolutely nothing beyond "there are words and numbers in it"

How would I go about making informed decisions like "if my planet size increases by a a factor x, I must adjust variably y by amount z to preserve a stockalike reentry experience"?

[NathanKell]

It's for RO, so the goal is "real numbers everywhere."

However, what you mostly want to tune are these:

@convectionFactor = 1.1

@machTemperatureScalar = 7.5 // ~6000 at 7.3km/sec

@machTemperatureVelocityExponent = 0.75

the factor is a multiplier to the transfer coefficient*; the others determine how a high-mach velocity is converted into a shock temperature. Stock has 21 as the Scalar, so that even 2000m/s is around 6000K, but you'll probably want something in between.

Possibly also the newtonian stuff and the turbulent stuff need fixing; if you alter hypersonic convection, you probably should alter newtonian to match so there's a smooth transition in heating over the transition range (M=2 to M=4).

*Convection works like this:

1. Get shock temperature, applying any behind-shockwave multipliers

2. Get part convection multiplier (i.e. is part of it occluded)

3. Get temperature delta (shock temp - part temp)

4. Get transfer coefficient.

5. Heat flux per exposed m^2 = coefficient * temperature delta * multiplier

shock temperature is aerodynamicHeatProductionFactor * velocity when below mach 2, and machTemperatureScalar * velocity^machTemperatureVelocityExponent when above mach 4 (well, technically machConvectionStart and machConvectionEnd not 2 and 4). The transfer coefficients are

Newtonian: (newtonianConvectionFactorBase + velocity^newtonianVelocityExponent) * density^newtonianDensityExponent * newtonianConvectionFactorTotal, or just convectionFactorSplashed if splashed.

Hypersonic: convectionFactor * density^convectionDensityExponent * velocity^convectionVelocityExponent

the temperatures and the coefficients are interpolated when velocity > M=2 and < M=4.

Edited July 2, 2015 by NathanKell

[Streetwind]

Nice, that clears up some things and should be helpful to a lot of authors of rescale configs!

[Bomoo]

Also what's up with Minmus being outside of Kerbin's SOI? I realize you're trying to be consistent with the 3.7x thing, but surely it's be fine to fudge cases like that a little bit for the sake of playability. I'm not saying make it trojan moon or whatever that other 3.7x mod does, but bringing it a bit closer, inside Kerbin's SOI, would probably be okay.