How do I balance these Stock edits?

[MisterDoubleSevens]

Basically, I wanted to make some purposely OP stock edits (GASP)... but not too OP. Anyone can give an engine crazy thrust and tiny fuel usage, I want to make a high-power (and high-power-drain!) Ion engine. And then make other parts so that it actually works, because the power-drain is too much for stock parts to handle (despite the thrust actually being pretty bog-standard for 1m engines). Partially because Ion engines are cool, partially because I just wanted a crazy unrealistic Ion engine (something more akin to the Twin-Ion-Engine fighters of Star Wars, hence the name PB-TIE).

Now, tested them a bit, the PB-TIE (working name) uses up 894 EC/sec. Knowing this, I purposely set the REAC to only give 400 so it can't power the engine on its own - I also made it heavy (but probably not nearly heavy enough) because there needed to be a drawback to lifting that much power generation.

The large Xenon container was just made because I needed a bigger radial size. I'm about 60% sure I calculated the volume of a cylinder when the diameter is doubled wrong - I squared it but that seems really off.

EDIT: How did I think squaring the volume worked for doubled radius and doubled height of a cylinder... and how did I mistake 700*7 for 700*700? Ah well, fixed now - the multiplier I was looking for was 8. Thanks FleshJeb!

EDIT: I mistook the net EC usage with the REAC and TIE both running (440-490 EC/sec) for the TIE's actual EC usage of 894 EC/sec.

{
name = ionEngine
module = Part
author = NovaSiliskomesh = model.mu
scale = 1
rescaleFactor = 2
node_stack_top = 0.0, 0.2135562, 0.0, 0.0, 1.0, 0.0, 1
node_stack_bottom = 0.0, -0.1872844, 0.0, 0.0, 1.0, 0.0, 1
TechRequired = ionPropulsion
entryCost = 16800
cost = 57000
category = Utility
subcategory = 0
title = PB-TIE Large Electric Propulsion
manufacturer = Ionic Symphonic Protonic Electronics
description = By emitting ionized xenon gas through a larger thruster port with a higher velocity, this bigger cousin of the PB-ION maintains the same incredible efficiency while also gaining serious thrusting power. All claims that the PB-TIE uses more energy than a small country are completely unfounded.
attachRules = 1,0,1,1,0
// --- standard part parameters ---
mass = 2.50
dragModelType = default
maximum_drag = 0.2
minimum_drag = 0.2
angularDrag = 2
crashTolerance = 12
maxTemp = 4600
MODULE
{
name = ModuleEngines
thrustVectorTransformName = thrustTransform
exhaustDamage = False
ignitionThreshold = 0.1
minThrust = 0
maxThrust = 200
heatProduction = 0
PROPELLANT
{
name = ElectricCharge
ratio = 5.4
}
PROPELLANT
{
name = XenonGas
ratio = 0.15
}
atmosphereCurve
{
key = 0 8200
}

}
MODULE
{
name = FXModuleAnimateThrottle
animationName = colorAnimation
dependOnEngineState = True
responseSpeed = 0.5
}
MODULE
{
name = ModuleTestSubject

// nowhere: 0, srf: 1, ocean: 2, atmo: 4, space: 8
environments = 15

useStaging = True
useEvent = True
}
}

PART

{
name = rtg
module = Part
author = NovaSilisko
mesh = model.mu
scale = 1
rescaleFactor = 3
node_stack_top = 0.0, 0.3268025, 0.0, 0.0, 1.0, 0.0, 0
node_stack_bottom = 0.0, -0.3268025, 0.0, 0.0, 1.0, 0.0, 0
node_attach = 0.0, -0.3268025, 0.0, 0.0, -1.0, 0.0, 0
TechRequired = specializedElectrics
entryCost = 382000
cost = 330000
category = Utility
subcategory = 0
title = PB-REAC Thermonuclear Electricity Generation Device
manufacturer = Ionic Symphonic Protonic Electronics
description = Through exploitation of the violent fission of Blutonium-235, it's possible to generate absolutely massive amounts of energy. Enough to power a small country, or perhaps a PB-TIE.
attachRules = 1,1,1,0,0
// --- standard part parameters ---
mass = 32.00
dragModelType = default
maximum_drag = 0.2
minimum_drag = 0.2
angularDrag = 2
crashTolerance = 9
maxTemp = 10000
MODULE
{
name = ModuleGenerator
isAlwaysActive = true
OUTPUT_RESOURCE
{
name = ElectricCharge
rate = 500
}
}
}

PART

{
name = xenonTank
module = Part
author = NovaSilisko
mesh = model.mu
scale = 1
rescaleFactor = 2
node_stack_top = 0.0, 0.1404661, 0.0, 0.0, 1.0, 0.0, 0
node_stack_bottom = 0.0, -0.1404661, 0.0, 0.0, 1.0, 0.0, 0
TechRequired = ionPropulsion
entryCost = 8800
cost = 30000
category = Utility
subcategory = 0
title = PB-X300 Xenon Container
manufacturer = Probodobodyne Inc.
description = Designed with the PB-TIE in mind, this larger, heavier, and full-er container holds enough Xenon to power the regular PB-ION for years. It's still a very good thing the invention of the PB-TIE made such a long burn unnecessary.
attachRules = 1,0,1,1,0
mass = 0.40
dragModelType = default
maximum_drag = 0.2
minimum_drag = 0.3
angularDrag = 2
crashTolerance = 6
maxTemp = 2900
breakingForce = 50
breakingTorque = 50
RESOURCE
{
name = XenonGas
amount = 5600
maxAmount = 5600
}
}

PART

+Changed X300 (large Xenon tank) from 4900 Xenon to 5600 Xenon, in accordance with actual math and not random guesses and a failure to comprehend volume. Also made it lighter (1.5 tons -> 0.4 tons), because logically it'd have the same density as the stock one, so volume*8 w/ constant mass = density*8. Unless I'm failing to comprehend math again.

-Made REAC (the fission RTG) four times heavier (8 tons -> 32 tons), because I looked up "portable fission reactors" and the closest thing we have just happens to be 3 meters wide and 15 meters tall (roughly the same size as the REAC)... and weighs 500 tons. Source. It's pure Rule Of Fun that I'm keeping the weight so low (that and the RTG model clearly has much less heavy shielding than the SSTAR, probably because stock RTGs work vi decay not fission) No more nonsense with the TIE lifting the REAC at 2/3rd throttle.

+I went into the TIE and lowered the Xenon flow ratio (0.30 -> 0.15), so it's now more Xenon efficient. Still a power-hungry monster that can devour the contents of even the largest battery in mere seconds.

+Boosted REAC's output (400 EC/sec -> 500 EC/sec) so that two REACs can power one TIE... barely. Still means you're lifting 64 tons (32*2) to power a 200 thrust engine (with 8200 ISP and the lightest fuel in the game). Or you could power an Eeloo space station.

Edited September 11, 2014 by MisterDoubleSevens
UPDATE! x2

[sal_vager]

Balance is really up to you, they are your parts but I bet there's a few people in Addon affairs who can help, so I've moved this there

[Andrew Hansen]

I honestly think that rather than editing the stock parts, you might as well install a mod like Near Future Propulsion. There you can actually build reactor + engine designs with up to 2 G's of TWR! You can even build a Tylo SSTO spaceplane.

Optionally, delete some stock parts so that you only have the modded engines to deal with.

[FleshJeb]

The large Xenon container was just made because I needed a bigger radial size. I'm about 60% sure I calculated the volume of a cylinder when the diameter is doubled wrong - I squared it, but that seems really off.

That's a fun change; I might have to try it myself. :-)

V=(pi)*r^2*h

Did "h" double as well? Volume (and fuel mass) should go up by a factor of 8.

Interestingly, the "nozzle" cross section only quadruples, so for the same mechanism/performance characteristics, thrust would only be 8kN. Since yours is 200kN, your exhaust velocity (and thus your Isp) is either 25 times higher, or you're somehow dumping a LOT more fuel through.

Nevermind, I just got smacked by this article here: http://en.wikipedia.org/wiki/Ion_thruster. You're best off following this: http://tvtropes.org/pmwiki/pmwiki.php/Main/RuleOfCool ;-)

[MisterDoubleSevens]

V=(pi)*r^2*h

Did "h" double as well? Volume (and fuel mass) should go up by a factor of 8.

Ah, I multiplied by a factor of 7, so I underestimated. (Why did I say I squared it? If I squared the base value of 700, I'd have 490000 Xenon in one tank. 700*7 =/= 700^2)

Interestingly, the "nozzle" cross section only quadruples, so for the same mechanism/performance characteristics, thrust would only be 8kN. Since yours is 200kN, your exhaust velocity (and thus your Isp) is either 25 times higher, or you're somehow dumping a LOT more fuel through.

Nevermind, I just got smacked by this article here: http://en.wikipedia.org/wiki/Ion_thruster. You're best off following this: http://tvtropes.org/pmwiki/pmwiki.php/Main/RuleOfCool ;-)

Yeah, the ultrapowerful (and power-hungry) Ion engine is pure Rule Of Cool.

---------

Made a few tweaks, instead of reposting the whole .cfgs, I'll just highlight changes:

+Changed X300 (large Xenon tank) from 4900 Xenon to 5600 Xenon, in accordance with actual math and not random guesses and a failure to comprehend volume. Also made it lighter (1.5 tons -> 0.4 tons), because logically it'd have the same density as the stock one, so volume*8 w/ constant mass = density*8. Unless I'm failing to comprehend math again.

-Made REAC (the fission RTG) four times heavier (8 tons -> 32 tons), because I looked up "portable fission reactors" and the closest thing we have just happens to be 3 meters wide and 15 meters tall (roughly the same size as the REAC)... and weighs 500 tons. Source. It's pure Rule Of Fun that I'm keeping the weight so low (that and the RTG model clearly has much less heavy shielding than the SSTAR, probably because stock RTGs work via decay, not fission.) No more nonsense with the TIE lifting the REAC at 2/3rd throttle.

+I went into the TIE and lowered the Xenon flow ratio (0.30 -> 0.15), so it's now more Xenon efficient. Still a power-hungry monster that can devour the contents of even the largest battery in mere seconds.

I honestly think that rather than editing the stock parts, you might as well install a mod like Near Future Propulsion. There you can actually build reactor + engine designs with up to 2 G's of TWR! You can even build a Tylo SSTO spaceplane.

Optionally, delete some stock parts so that you only have the modded engines to deal with.

I'm making these personal edits/copies as I want them. Partially because I want to get experience self-modding things, because I've seen around these forums the suggestion that "bored of KSP? either make a roleplay save, or make a mod"; and partially because it's fun to make OP stock edits that end up being balanced by sheer virtue of your lack of understanding of part .cfgs (yes, the 440-490 EC/sec for a measly 200 thrust was an accident).