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Stockalike RF Engine Configs v3.2.6 [01/20/19][RF v12]


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Link for SpaceY: http://forum.kerbalspaceprogram.com/threads/100408

And yeah, the KSPI Methane Engine is included in the Stockalike config. (link to line on GitHub) I didn't change the ISP quite so high. The specs were 320/380 or so, but mine has 300/360 or so.

O.o

I don't know why I didn't think of that before. I was looking in the KSPI_MFS file for the MM patch, instead of the normal engine config file... :blush:

EDIT: MAJOR problem with the MM patch, though...

And yeah, the KSPI Methane Engine is included in the Stockalike config. (link to line on GitHub) I didn't change the ISP quite so high. The specs were 320/380 or so, but mine has 300/360 or so.

You actually *decreased* the ISP of the engine (from 309/368 to 300/365) when one of the biggest issues that was wrong with it already was that the ISP was lower than the real Raptor engine (321/380). So you actually made the problem *worse*. Remember that Meth/LOX *is not* Kerosene/LOX, it's an entirely different fuel-mode (more similar to LH2/LOX in ISP and fuel-density). How many LH2/LOX engines have you nerfed so they match Kerosene/LOX engines in ISP? (that's basically what you did the equivalent of here)

You also more than DOUBLED the cost of the part (from 3050 to 6554), while only reducing its mass by 1.3 tons (from 3.5 to 2.2) and increasing its thrust by 25 kN (from 1425 to 1450). And you over-corrected the burn ratio (the ratio you uses is about stoichiometric, whereas the *real* engine burns fuel-rich. The *correct* fuel/LOX ratio should be about .4 to .6 or .39 to .41 instead of .443 to .557 (the previous RealFuels ratio) or .375 to .625 (the ratio you are now using).

So, OVERALL, you actually made the engine *less* realistic than it already was. The costs are now too high (the per-unit costs were correct before: Raptor engines would be cheap to manufacture for their performance- remember, they're meant to be used in clusters of 9 or more... To increase costs realistically, increase the "EntryCost"), the ISP is LOWER when it needed to be made HIGHER (remember, the real-world figure is 321/380- which the RAPTOR *needs* to be able to compete with LH2/LOX, due to its much lower fuel-density than Kerosene/LOX), and the mass is too low for an engine that size (the thrust needs to be 59.1% higher than the original instead of the mass being 37% lower if you want to maintain the TWR you choose). Also, remember if you reduce engine mass without reducing heat production (like you did) you cause the engine to overheat much more easily (I'm not even sure the engine can safely be fired at full-throttle now: which is *not* as issue the real Raptor would have.)

I drew up and posted below a revised config I'd like you to include. Please do- I really need a more accurate RealFuels-compatible Meth/LOX chemical engine for my current playthrough...

Regards,

Northstar

P.S. Whatever fuel/LOX burn-ratio you settle on also needs to be mirrored in the base RealFuels mod, for the KSP-Interstellar NTR fuel options. Currently those suffer from burning far too fuel-rich when it Meth/LOX mode as well...

Edited by Northstar1989
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@Raptor831

Never one to uselessly point out problems when I have the means to easily fix them, I went and fixed the MM patch for the engine. Here is the version I *suggest* using:


@PART[FNMethaneEngine]:FOR[RealFuels_StockEngines] //
{
@maxTemp = 1948
@entryCost = 32000
@MODULE[ModuleEngines]
{
@maxThrust = 2270
@heatProduction = 181
@atmosphereCurve
{
@key,0 = 0 380
@key,1 = 1 321
}
!PROPELLANT[LiquidFuel] {}
!PROPELLANT[Oxidizer] {}
!PROPELLANT[MonoPropellant] {}
PROPELLANT
{
name = LqdMethane
ratio = 39
DrawGauge = True
}
PROPELLANT
{
name = LqdOxygen
ratio = 61
}
}

MODULE
{
name = ModuleEngineConfigs
type = ModuleEngines
techLevel = 7
origTechLevel = 7
engineType = L+
origMass = 3.5
configuration = LqdMethane+LqdOxygen
modded = false
CONFIG
{
name = LqdMethane+LqdOxygen
maxThrust = 2270
heatProduction = 181

PROPELLANT
{
name = LqdMethane
ratio = 0.39
DrawGauge = True
}
PROPELLANT
{
name = LqdOxygen
ratio = 0.61
}
IspSL = 1.0506
IspV = 1.0506
throttle = 0

ModuleEngineIgnitor
{
name = ModuleEngineIgnitor
ignitionsAvailable = 48
autoIgnitionTemperature = 800
ignitorType = Electric
useUllageSimulation = true
IGNITOR_RESOURCE
{
name = ElectricCharge
amount = 14.5
}
}
}

}
!MODULE[ModuleEngineIgnitor] {}
MODULE
{
name = ModuleEngineIgnitor
ignitionsAvailable = 48
autoIgnitionTemperature = 800
ignitorType = Electric
useUllageSimulation = true
IGNITOR_RESOURCE
{
name = ElectricCharge
amount = 14.5
}
}
}

Comments/Questions on my changes:

- I deleted the line entirely to change the engine mass from the first part of the config, and changed the "origMass" line to 3.5 (is that something that even needs to be included if the mass isn't changed?)

- I removed the line to change the per-unit cost from the first part of the config (the original cost was fine). Instead, I more than doubled the EntryCost (the cost to unlock the part) to 32,000 to reflect the considerable design challenges. Players who don't use EntryCosts can/should be able to still get the engine cheaply- one of the MAJOR advantages of the Raptor engine is that it would be *much* cheaper to manufacture due to the less stringent engineering margins Full Flow Staged Combustion enables... (despite its higher performance, the Raptor as currently designed is actually *further* from its theoretical maximum for an engine of its type than current rocket engines designs- to reduce costs and improve reusability...)

I'm sure you're aware of the exponential relationship between engineering margins and cost- and the engine was already a bit pricey for a 2.5 meter engine (at least compared to several other mod engines from KW Rocketry and NovaPunch2), so it didn't make sense to change the per-unit costs... The engine also requires the extremely-advanced Experimental Rocketry tech node- so between the high Science and part buy-in costs (which were already high, and I more than doubled) of the engine, there ought to be more of an economic advantage when simply using it as a heavy-lift engine (considering this is its design real-life role), from a gameplay-balance perspective, or players will never bother to unlock it in the first place...

- I changed the ISP to 321/380, the real-world stat. Yes, that's much better than any Kerosene/LOX engine (as you noticed with the XLS file), AND IT SHOULD BE. Meth/LOX is an entirely *different* fuel-mixture than Kerosene/LOX, more similar to LH2/LOX in its performance *and fuel-density*. You wouldn't nerf LH2/LOX engines to match the ISP of Kero/LOX engines, would you?

- I increased the thrust to 2270 kN maxThrust. *This was to respect the TWR you selected before.* I came up with this number by calculating the TWR you had before, and implementing it for an engine that weighed 3.5 tons instead of 2.2 tons, then rounding it to the nearest multiple of 5 (from 2267.x to 2270 kN, to make it easier to look at). Keep in mind the *real* 2.5 meter Raptor would produce 8200kN of thrust with a mass of just under 7 tons (6.973 tons, according to calculations from its known thrust and TWR predictions)- so the TWR is still roughly half what it is in real life.

- I changed the fuel burn-ratio to .39/.61, to make it more fuel-rich (like the real Raptor). The real Raptor burns fuel-rich to improve ISP and reduce heat generation- although I can't seem to find any hard numbers of precisely how much so. The new ratio you selected before was nearly stoichiometric, however, and thus far too LOX-rich.

Please use my version of the config instead in the dev version and next release (I would suggest just pasting this in and pushing a release, if you have the time). Let me know the answers to my questions when you are able.

Regards,

Northstar

P.S. You might initially think the engine currently has too much thrust for its cost. But consider the cost-effectiveness of SRB's, against which this engine is competing for a role in helping to lift Heavy Launch Vehicles... It's not *MEANT* to be in the same class as normal chemical rocket engines- Full Flow Stage Combustion is a whole different beast when it comes to performance, compared to older rocket engines.

Edited by Northstar1989
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@Robotengineer Yes, they are in the next release. Just hadn't gotten to them yet (since they slipped out of my install!).

@Northstar1989 First, I want to say thanks for the feedback. Always helps to make a better end product.

I did update the config, but I didn't quite use your version of it. As an explaination:

All of this config is produced by the XLS. I don't code these by hand at all! If I did, I'd never play KSP ever due to my hands cramping from typing. :wink: As such, if I can't get the XLS to work with me, it doesn't happen. So, to make a fundamental change (like adding a new combustion cycle) I kind of have to invent a different wheel. So, for this one I've created a FFSC flag that will give a Raptor-like "filter" to any engine. In detail, the entry cost of the engine is doubled (research costs), the "goal TWR" target is doubled (to adjust for the lower mass of these engines), and the part cost formula has an additional factor added to halve the cost. What this means is that if you increase the ISP of the engine to match a Raptor-like engine, you'll get something close to what you described in the posts above.

For example, the new KSPI methane engine has an IspSL of 311 and a IspV of 379. The mass sits at 1.9, and the cost rounds out to about 4200. Thrust is still 1450. Entry cost doubles what is in the KSPI config. All of the other details follow the XLS computations (like heat production, max temp), which I'm inclined to let be. I did realize I goofed up the mass ratio of methalox by a good bit, so I adjusted that to 3.5 from 4.5. Found some data on other methalox engines which finally had this number (the old one was a guess based on this Wikipedia page with a fudge). All methalox engines have been adjusted as a result.

Cost is something I just started adjusting with these configs, so that is still in flux. As of right now they are scaled to thrust/efficiency/mass. So, more thrust = more cost, higher efficiency = more cost, lower mass = more cost. I haven't had time to dig into the formula that was set up to calculate this, I'm just using it as a base. But as I mentioned somewhere on the thread, the cost is scaled so that the Mainsail cost in stock = Mainsail cost in RFStockalike. Everything else has probably changed some. This also comes with the reduced fuel costs of RF (which I have not touched). So, it's not really a question of how the costs change from stock, but how they are balanced to each other now. The way I set up the FFSC cycle it should be comparable to another engine of similar thrust/size at a given tech level. So, more efficient for same cost.

Also, I really don't intend on making any real-life analogs in this config. None of the numbers in mod configs are really close to true engine stats, so I'd have to do essentially what the Realism Overhaul folks have already done, but with the added annoyance of scaling these engines to the stock size steps. I'm really making a RftS config for stock/6.4x sizes.

In any case, the repo is updated, and I'll be pushing a "release" soon. You can download from the repo at any time, so if you're itching to get the latest, feel free!

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Did you want to include the NFP engine configs into the release? I thought i had read that somewhere, not sure though. And thx for including the ntr fix!

Really, that config needs to be included with NFP. It makes changes to the cost of Xenon, adds some procedural tanks, adjusts the current tanks to use RF resources, in addition to adjusting the engines. It's a bit outside the scope of the Stockalike config. aristurtle did a good job with it though. You can ask Nertea if he wanted to include that config, since the license of the NFP config lets you. Since I'm at a loss when it comes to electrics, it might be useful. Also, Starman4308 was working on some electric propulsion balancing, so once that's all fleshed out we might be able to apply those things to NFP.

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@Northstar1989 First, I want to say thanks for the feedback. Always helps to make a better end product.

Glad I could be of help!

All of this config is produced by the XLS. I don't code these by hand at all! If I did, I'd never play KSP ever due to my hands cramping from typing. :wink: As such, if I can't get the XLS to work with me, it doesn't happen. So, to make a fundamental change (like adding a new combustion cycle) I kind of have to invent a different wheel. So, for this one I've created a FFSC flag that will give a Raptor-like "filter" to any engine. In detail, the entry cost of the engine is doubled (research costs), the "goal TWR" target is doubled (to adjust for the lower mass of these engines), and the part cost formula has an additional factor added to halve the cost. What this means is that if you increase the ISP of the engine to match a Raptor-like engine, you'll get something close to what you described in the posts above.

For example, the new KSPI methane engine has an IspSL of 311 and a IspV of 379. The mass sits at 1.9, and the cost rounds out to about 4200. Thrust is still 1450. Entry cost doubles what is in the KSPI config. All of the other details follow the XLS computations (like heat production, max temp), which I'm inclined to let be. I did realize I goofed up the mass ratio of methalox by a good bit, so I adjusted that to 3.5 from 4.5. Found some data on other methalox engines which finally had this number (the old one was a guess based on this Wikipedia page with a fudge). All methalox engines have been adjusted as a result.

FFSC has higher ISP and TWR largely because of the higher Chamber Pressures it enables. The chart you linked to assumes a Chamber Pressure of 6,895 kPa (1000 psi).

But both the Space Shuttle Main Engines and the Raptor use much higher chamber pressures. The SSME's used a Chamber Pressure of 2994 psi, for instance (according to Wikipedia), and Full Flow Staged Combustion engines (such as the Raptor) are capable of even higher Chamber Pressures. The following comes directly from the "Design" page of the Wikipedia article for the Raptor (emphasis added).

Additional characteristics of the full-flow design that are projected to further increase performance or reliability include

- eliminating the fuel-oxidizer turbine interseal, which is a potential point of failure in more traditional engine designs

- lower pressures are required through the pumping system, increasing life span and further reducing risk of catastrophic failure

- ability to increase the combustion chamber pressure, thereby either increasing overall performance, or "by using cooler gases, providing the same performance as a standard staged combustion engine but with much less stress on materials, thus significantly reducing material fatigue or [engine] weight."

Thus, despite a 1000 psi Meth/LOX engine using conventional cycles only being able to achieve an ISP of 368 seconds (not coincidentally, the vacuum ISP used for the base KSP-Interstellar part- Fractal_UK probably used that Wikipedia chart without referencing the actual Raptor stats or examining the chamber pressure the calculations were based on...), a FFSC Meth/LOX engine can *easily* achieve 2 or 3 times the chamber pressure (the SSME's had 3 times the Chamber Pressure, and didn't use FFSC), and thus an ISP of 380 seconds in vacuum (the predicted Raptor ISP) actually becomes quite conservative...

Bottom Line: I would advise matching the projected ISP values for the real Raptor design. The numbers you used (311/379) are still too conservative for Full Flow Staged Combustion (321/380), and don't allow the Meth/LOX engine to compete effectively with LH2/LOX launch-stages...

Cost is something I just started adjusting with these configs, so that is still in flux. As of right now they are scaled to thrust/efficiency/mass. So, more thrust = more cost, higher efficiency = more cost, lower mass = more cost. I haven't had time to dig into the formula that was set up to calculate this, I'm just using it as a base. But as I mentioned somewhere on the thread, the cost is scaled so that the Mainsail cost in stock = Mainsail cost in RFStockalike. Everything else has probably changed some. This also comes with the reduced fuel costs of RF (which I have not touched). So, it's not really a question of how the costs change from stock, but how they are balanced to each other now. The way I set up the FFSC cycle it should be comparable to another engine of similar thrust/size at a given tech level. So, more efficient for same cost.

Cost increased from 3050 to 4200 according to your latest post. The thrust is 1450 (compared to 1500 for the Mainsail in stock- but higher in RealFuels with tech-levels). So it actually seems to be about right for the per-unit cost, considering FFSC is *much* more advanced technology (and the EntryCost is doubled to reflect this) designed with greater cost-effectiveness in mind. However, the overall thrust is still too low- the Meth/LOX engine should have a *higher* thrust than the Mainsail (the Raptor has a higher thrust than almost any comparable-sized engine). The mass should also be increased proportionally (the Raptor isn't as much lighter compared to comparable-sized engines as what you have in the config).

So basically, the Meth/LOX engine is still too light and produces too little thrust... Players can still lift heavier payloads with a Mainsail in LH2/LOX mode, which should *NOT* be the case (the Raptor enables larger payloads for the same diameter rocket due to the fuel-density advantages of Meth/LOX and the overall thrust advantages of FFSC). Remember, Meth/LOX is a *lower ISP* fuel than LH2/LOX- so if the engine thrust is also lower, players will be stuck with a *much* lower payload-capacity for the engine...

With the current balance, players still have ZERO incentive to use the Meth/LOX engine over a Mainsail (which has a lower EntryCost, is available earlier, can achieve higher ISP when in LH2/LOX mode, and still has a higher base thrust even in LH2/LOX mode...) This needs to be changed. Please adjust upwards the engine mass, ISP (to 321/380), and thrust. I would recommend adjusting the XLS equation so that the cost stays at what it currently is (about 4200) when making these changes, with the new figures becoming the FFSC baseline (there needs to be SOME incentive to use the Meth/LOX and other FFSC engines- if you increase cost much further it won't be worth the *huge* EntryCost...)

Also, I really don't intend on making any real-life analogs in this config. None of the numbers in mod configs are really close to true engine stats, so I'd have to do essentially what the Realism Overhaul folks have already done, but with the added annoyance of scaling these engines to the stock size steps. I'm really making a RftS config for stock/6.4x sizes.

In any case, the repo is updated, and I'll be pushing a "release" soon. You can download from the repo at any time, so if you're itching to get the latest, feel free!

Thanks for all the hard work, as always!

Please consider increasing the Meth/LOX engine thrust- currently the Mainsail has much higher thrust *and* ISP when in LH2/LOX mode!

Regards,

Northstar

P.S. In the base KSP-Interstellar game, the Meth/LOX engine doesn't have to compete against the ISP of LH2/LOX engines- so the stats don't need to be nearly as realistic to make it worth using. However with LH2/LOX engines in play (with RealFuels), the Meth/LOX engine NEEDS more realistic Thrust/ISP stats to be competitive...

Edited by Northstar1989
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Ion engines are done. My sole question is if you want me to include the spreadsheet I used to calculate the parameters along with the pull request.

The three custom configs range from 1800s at 2.7 kN of thrust to 3600s at 0.675 kN of thrust, all consuming approximately 4 Gigantors' worth of electricity (the higher-thrust variants use more). The stockalike is for people who want stock performance. Based on feedback from Nertea, I didn't touch atmospheric Isp, so ion gliders are still a go.

I would've liked to have this sooner, but real life got in the way.

EDIT: I just noticed my Isp values were a half-hour, 45 minutes, and an hour. I completely did not plan this: I was just tweaking them to get somewhat saner values.

EDIT #2: Anyone know some decent open-source software for low-acceleration maneuvers? Trying to do standard manuever nodes for interplanetary transit is just about impossible in RSS with an ion engine, and if I can steal the code logic, I can write a kOS script.

Edited by Starman4308
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I've made some more adjustments to the FFSC option and committed those to the repo. In short:

I've hardcoded a bump in Isp for FFSC (higher chamber pressures) and brought the mass goal down for any given thrust (lower mass from fewer parts). This should more closely mimic the FFSC improvements that the Raptor engine is trying to achieve. You could technically drop the Isp requirements and decrease the mass for a really hefty TWR. But, really, when using the XLS for this, you're going to need to play fair, because you can get some insane costs/TWR if you wanted to at respectable Isp, or get some insane Isp for respectable TWR/mass.

In specifics, the Deinonychus is down to a mass of 1.3, with a thrust of 1425 (which is the "stock" value I messed up before). Cost is 4059 (Mainsail is still 5650), and Isp is 314/382 (SL/V). This is a TWR of over 100, which is somewhere in the neighborhood of 50% better than the Mainsail, so your delta-V should be much better with the Deinonychus. This is a really good engine by the numbers at this point. True, hydrolox gives better Isp, but who wants to haul (and cool) LH2 around everywhere. Or make it in situ, for which the Deinonychus is designed.

All in all, I think the Deinonychus should have a fighting chance against a Mainsail. Also, the SpaceY engines have been adjusted this way, and one of the KSLO engines has been upgraded to a FFCS engine. There's a big hole for a 3.75m engine at around 3000 kN, though, and I'm not sure where that could come from. I might consider, as I suggested before, making some copies of current engines (namely KW, NP2, or AIES) that could be downloaded alongside RFStockalike to use for these purposes. Maybe the 3.75m Griffon and a 3.75m NP2 engine for 2500kN and 4000 kN? I don't know, but that's for another day.

Also, Northstar, where are you getting mass values for the Raptor? All I can find is conflicting numbers on the IspV (360-380), and thrust values. The Wikipedia articles aren't all that fleshed out, considering the Raptor isn't finished yet.

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Ion engines are done. My sole question is if you want me to include the spreadsheet I used to calculate the parameters along with the pull request.

The three custom configs range from 1800s at 2.7 kN of thrust to 3600s at 0.675 kN of thrust, all consuming approximately 4 Gigantors' worth of electricity (the higher-thrust variants use more). The stockalike is for people who want stock performance. Based on feedback from Nertea, I didn't touch atmospheric Isp, so ion gliders are still a go.

I would've liked to have this sooner, but real life got in the way.

EDIT: I just noticed my Isp values were a half-hour, 45 minutes, and an hour. I completely did not plan this: I was just tweaking them to get somewhat saner values.

EDIT #2: Anyone know some decent open-source software for low-acceleration maneuvers? Trying to do standard manuever nodes for interplanetary transit is just about impossible in RSS with an ion engine, and if I can steal the code logic, I can write a kOS script.

Submit the pull request without the XLS. PM me a link to the XLS and I'll add it in somewhere, just to have it in the repo.

Thanks a ton!!!

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High chamber pressure is incredibly necessary for high sea level specific impulse but of negligible value in vacuum. I suggest trying methalox out in RPA and do an analysis on differing chamber pressures.

Hydrolox example: RL-10A4-2 has 39bar Pc and 451s Isp in vacuum. SSME has 204bar Pc and 453s in vacuum. Note that they have nearly the same area ratio; an RL-10B-X with an Ae/At of 250 gets up to 470s in vacuum.

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High chamber pressure is incredibly necessary for high sea level specific impulse but of negligible value in vacuum. I suggest trying methalox out in RPA and do an analysis on differing chamber pressures.

Hydrolox example: RL-10A4-2 has 39bar Pc and 451s Isp in vacuum. SSME has 204bar Pc and 453s in vacuum. Note that they have nearly the same area ratio; an RL-10B-X with an Ae/At of 250 gets up to 470s in vacuum.

Another great tool, thanks. Turns out rocket science is actually hard, despite what von Kerman likes to say.

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Also, Northstar, where are you getting mass values for the Raptor? All I can find is conflicting numbers on the IspV (360-380), and thrust values. The Wikipedia articles aren't all that fleshed out, considering the Raptor isn't finished yet.

The mass values for the Raptor were back-calculated from the announced thrust and TWR values (8200 kn thrust in vacuum, TWR of approx. 120). Sounds like you're extremely close to the real-life TWR values if you're pushing over 100 now.


[B]More on the Math:[/B]

9.81 kN is the force of gravity on a metric ton at 1 g. Thus an engine with TWR = 120 produces 1177.2 kN of thrust per metric ton.

The Raptor would produce 8200 kN of thrust at a TWR of 120, therfore it should weigh approximately 6.9657 metric tons.

As for the ISP values, where did you find any besides 321/380 SL/vac? Those are the *only* reliable numbers I came across for the *latest* iterations of the Raptor. You were likely looking at earlier figures before they upgraded the designed thrust from 4400 kN to 8200 kN and vacuum ISP from 360 to 380? (all at the expense of mass and higher chamber pressures, however)

Regards,

Northstar

Edited by Northstar1989
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The mass values for the Raptor were back-calculated from the announced thrust and TWR values (8200 kn thrust in vacuum, TWR of approx. 120). Sounds like you're extremely close to the real-life TWR values if you're pushing over 100 now.


[B]More on the Math:[/B]

9.81 kN is the force of gravity on a metric ton at 1 g. Thus an engine with TWR = 120 produces 1177.2 kN of thrust per metric ton.

The Raptor would produce 8200 kN of thrust at a TWR of 120, therfore it should weigh approximately 6.9657 metric tons.

As for the ISP values, where did you find any besides 321/380 SL/vac? Those are the *only* reliable numbers I came across for the *latest* iterations of the Raptor. You were likely looking at earlier figures before they upgraded the designed thrust from 4400 kN to 8200 kN and vacuum ISP from 360 to 380? (all at the expense of mass and higher chamber pressures, however)

Regards,

Northstar

The wiki articles on the SpaceX Rocket engine families says 360 IspV. :shrug: TWR numbers make sense to. Which also means I'm in the right ballpark (if not a bit high) for the Deinonychus. Thrust plates aren't usually included in stated TWR values for engines, but the plates are included in KSP. So, my TWR of just over 100 is just about right.

Again, the only reason I'm staying with the 1425kN value for the thrust is because that's what it came with. I've done all the engines that way and I don't want to adjust thrust AND mass (and all they affect) for every engine.

That being said, I do see your point about the 2.5m core engine size needing something in the 1600-2000kN range. Something I'm keeping my eye on is the SpaceY thread, and this 2.5m engine. He's got it at 2000kN currently, and it looks to me like a lifter engine. The SpaceY stuff is already FFSC, so this would be in line to be just perfect for filling that empty role.

Alternatively, I may add some duplicated engines in various sizes to fill other roles with differing propellants. I'm no part maker, but I can certainly scale stuff and adjust stats.

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The wiki articles on the SpaceX Rocket engine families says 360 IspV. :shrug: TWR numbers make sense to. Which also means I'm in the right ballpark (if not a bit high) for the Deinonychus. Thrust plates aren't usually included in stated TWR values for engines, but the plates are included in KSP. So, my TWR of just over 100 is just about right.

Ahh, I didn't know that. Makes sense to me- a TWR of 120 was on-par with some of the best rocket engines ever built/designed, and the Raptor already has one of the highest thrust to cross-sectional area ratios ever designed. Normally you have to make trade-offs in a rocket's design...

Again, the only reason I'm staying with the 1425kN value for the thrust is because that's what it came with. I've done all the engines that way and I don't want to adjust thrust AND mass (and all they affect) for every engine.

I was actually thinking (and briefly suggested- but then edited out of my post) that you just leave the original mass of 3.5 tons intact, and up-rate the thrust to 4120 kN (corresponding to a TWR of 120- or use a lower thrust value if you don't think the thrust plave was included in the figure of 120...) But then I changed my mind about that, because what you've done with all the other engines is tried to maintain the thrust and adjusted the mass instead- even if keeping the mass and adjusting thrust would be more realistic.

That being said, I do see your point about the 2.5m core engine size needing something in the 1600-2000kN range. Something I'm keeping my eye on is the SpaceY thread, and this 2.5m engine. He's got it at 2000kN currently, and it looks to me like a lifter engine. The SpaceY stuff is already FFSC, so this would be in line to be just perfect for filling that empty role.

Alternatively, I may add some duplicated engines in various sizes to fill other roles with differing propellants. I'm no part maker, but I can certainly scale stuff and adjust stats.

Sounds great to me!

Although, FFSC is an extremely rare and difficult-to-engineer (but high-performance) cycle. Where did you get your information that the SpaceY R1 engine should be FFSC? The fact that its ISP closely follows the RP-1 (lower ISP than the Mainsail) leads me to believe it is probably *not* FFSC...

Thanks once again for all your hard work Raptor!

I'm happy with the state of things now- the Math/LOX engine may still not be 100% realistic (its thrust and mass values are both too low for its cross-sectional area), but it's now gotten the same treatment as all the other engines (that is, its TWR and ISP values are realistic, even if thrust and mass levels are not due to maintaining the original thrust figures), which is good enough for me!

Regards,

Northstar

Edited by Northstar1989
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@Northstar1989 I didn't get any information about it being FFSC, I just declared it so in my configs. Isp is flexible to me, since in KSP stock it's only a reflection of the engine's intended use. (High Isp = orbital/vacuum engine, low Isp = launch engine). Plus, the R1 was stated to be lower mass and higher thrust than the Mainsail, both of which would apply to FFSC engine. Plus, all of the SpaceX-inspired stuff goes into a certain category (fuel types, tech levels, etc) within the configs.

And mostly because I wanted it to be that way. :) Also kind of fits SpaceY parts into it's own niche (advanced tech, excellent stats, but high entry cost), giving them a certain personality within RFStockalike.

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And the new SpaceY engines are up. OP is updated, new release is on GitHub.

Also updated the ModuleRCSFX module in the download to v3.3. If you already have 3.3, you don't need to overwrite anything.

Thanks raptor...do you happen to know if your configs are compatible with x64 ksp if we use the (unsupported)x64 version of RealFuels?

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Thanks raptor...do you happen to know if your configs are compatible with x64 ksp if we use the (unsupported)x64 version of RealFuels?

Honestly, I have no idea. I'm on a Mac, so I'm 32-bit all the way, whether I like it or not. :wink:

Theoretically, they should work as long as Real Fuels is working, since they are just configs that use Real-Fuels-created modules. But I make no guarantees. And in reality, I can't troubleshoot any 64-bit issues, so I'd be unable to give support if/when there is an issue.

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Honestly, I have no idea. I'm on a Mac, so I'm 32-bit all the way, whether I like it or not. :wink:

Theoretically, they should work as long as Real Fuels is working, since they are just configs that use Real-Fuels-created modules. But I make no guarantees. And in reality, I can't troubleshoot any 64-bit issues, so I'd be unable to give support if/when there is an issue.

Understood! Yeah i'm dual booting ubuntu on my MBP to see how the 64bit world is...thanks for this config regardless!

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