FreeThinker

KSP Interstellar Extended Continued Development Thread

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Posted (edited)
On 5/15/2020 at 6:52 PM, AntaresMC said:

LF has to be LH2 to have the nerva work with that Isp, and pressurized, gaseous O2 as oxidizer (yes, I know is a stupid idea, but, better thoughts?) would make for the low densities and absurdly heavy tanks. The low Isp for HydroOx is explained with bad engineering abilities from the kerbals (that also explain the awful oxidizer choice), and because of that, they hired you to design/fly, but give you the parts done beacuse of low budget XD

Stock LiquidFuel is pretty magical stuff, it behaves as hypergolic fuel but isn't toxic like hydrazine, remains liquid a super low temperatures and doesn't spontaneous decompose at high temperatures, doesn't require any cooling and heating to remain liquid, and has a density 12 times as high as Liquid Hydrogen, releases excess energy when heated to 2500K and decomposes into hydrogen rich gas with an exhaust speed of 80% of pure hydrogen. Also pumping between tanks can be done for free without the need of Megawatt turbo-pumps. 

In Interstellar I try to balance it by consistently applying the horrible mass ratio as used in stock. It isn't much but given the fact that every gram count,  it adds up.

Edited by FreeThinker

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16 hours ago, Mad-Medic said:

New Designed z-pinch aerospike into the testing process, almost done...ZaRrNZUYe0Q.jpg

The fact that the engine no longer has integrated air intakes surrounding the reactor, makes it a lot more versatile, suitable for Horizontal Take of and landing SSTO.

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Posted (edited)
15 hours ago, FreeThinker said:

Stock LiquidFuel is pretty magical stuff, it behaves as hypergolic fuel but isn't toxic like hydrazine, remains liquid a super low temperatures and doesn't spontaneous decompose at high temperatures, doesn't require any cooling and heating to remain liquid, and has a density 12 times as high as Liquid Hydrogen, releases excess energy when heated to 2500K and decomposes into hydrogen rich gas with an exhaust speed of 80% of pure hydrogen. Also pumping between tanks can be done for free without the need of Megawatt turbo-pumps. 

In Interstellar I try to balance it by consistently applying the horrible mass ratio as used in stock. It isn't much but given the fact that every gram count,  it adds up.

Yea, LF should remain as kinda unobtanium.

But, take into account that all bodies but Jool and Gilly (mabe Pol and Minmus, havent done the math) are made of degenerate matter and Kerbol is a brown dwarf several times older than the universe and as dense as a gas giant. 

And all parts are from 1/2 to 1/3 of their real counterparts, thing that would (moreless and assuming mass ratios keep againt the ^2/^3 law). We dont know if its toxic or not. With that awfull mass ratio it may even be a void layer with gold coating or something like that to trap the heat so well, and given the densities is obviously pressurized and overcooled. Dont know where the 80% H2s EV, actually, the Isps are quite pitty for H2, even for H2O, and we dont know chanber pressures nor temperatures, dont have better clue than the Nerv's Isp (rules out everithing but H2/He, and He aint the best fuel ever...). And the apparent hypergolicity may be beause of suspended aerosols of an easily igniteable (just a metal spark) monoprop. The pumping will be let to the same witchery that powers the orbital scanner (its actually canon xD).

I actually need a way to convert LF-O into some interstellar fuel (preferrably cheap) as do with N2H4-monoprop because of simplicity. I also use a list of USI mods (I believe everyone but Karbonite an the ones depend on it) an MKS uses a lot of LFO that I need different drills, converters, tanks and engines in the bases that suck up my load times and FPS, and last thing I need is to have another 10-20 parts EACH base I have  And as LFO is an awfull fuel compared to everything else of KSPIE, I have to use both... Or some patch to make MKS generators/transport credits/production chains use Interstellar fuels.

Edited by AntaresMC

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12 hours ago, FreeThinker said:

The fact that the engine no longer has integrated air intakes surrounding the reactor, makes it a lot more versatile, suitable for Horizontal Take of and landing SSTO.

Ive got a question: Why where there those intakes in the first place?

Dont tell me because the reaction is inside, and if that, explain me how THE HELL manages that heat. I assumed they were for cooling and the actual athmo burning mode was (as the non athmo) few meters back (Zpinch occurs in the big ring at the end) and exhaust driven in a simillar way to VISTA/Kerbstein (I have to talk about its thermodynamics in other post...), Opdalus and probably Unobtusstard as well. Even twith that trick (that renders redundant the thermal nozzle, the aerospike looked like the pellet gun, so is good for me), I evision a Z-pinch engine as a compact quasi-torch (I usually call it candle/lantern, depending on its Isp (former)/TWR(latter) orientation but they are both KSPIE engines Xd), with a high thermal power output (enough to power itself + the equivalent of a fission reactor) but an AWFULL waste heat footprint, that will render it unusable for power unless serious radiators used.

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On 5/18/2020 at 3:18 AM, Mandella said:

Then NERVA should not be working. I can't see LF as LH2. LF is stable and requires no cryogenic cooling -- it is a stand in for kerosene or other room temperature rocket fuel that also requires an oxidizer.

 

It works, thats evidence that we have to work with, the best thing I can think of to explain it is that the tanks being so obscenely heavy is because the kerbals are quite OCD with boiloffs and its all thermal insulation and some PV paint to power pelters. Any better thoughts that dont rule out  canon, gameplay proof?

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Posted (edited)
On 5/15/2020 at 12:46 AM, FreeThinker said:

D + He3 is indeed clean, but you always have side reactions like D-D which produce neutrons, which is still enough neutrons produced to kill anything nearby

 

You can make around the problem by having too much He3 (something like EnrichedFusionPellets), at least twice than normal.

N radiation falls below 1% as you go about 3-4x (dont remember exact numbers) the needed, but other problems start being unburnt, not-really-cheap-Id-say He3 and wasteful (economic and energy wise, hharder to ignite, less energy output) He3-He3 fusion, but being expensive is a small price for a torch and the engine still uses far below the theoretical max so...

Edit: Sorry, I monopolized quite a bit of the thread :P

Edited by AntaresMC

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Posted (edited)
5 minutes ago, AntaresMC said:

You can make around the problem by having too much He3 (something like EnrichedFusionPellets), at least twice than normal.

N radiation falls below 1% as you go about 3-4x (dont remember exact numbers) the needed, but other problems start being unburnt, not-really-cheap-Id-say He3 and wasteful (economic and energy wise, hharder to ignite, less energy output) He3-He3 fusion, but being expensive is a small price for a torch and the engine still uses far below the theoretical max so...

Yes, Helium3 absorbs neutrons, but it will really bite you efficiency. Also when Helium-3 absorbs a neutron it creates Tritium which can fuse with Deuterium to create a lot of neutrons.

Edited by FreeThinker

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Posted (edited)
24 minutes ago, FreeThinker said:

Yes, Helium3 absorbs neutrons, but it will really bite you efficiency. Also the Helium3 absorbs a neutron it creates Tritium which can fuse with Deuterium to create a lot of neutron.

Its wasteful, but the z-pinch can easily use like less than 5% of the total fusion ounput (less when afterburned), so you say "the tech improved" to count for that and youre done. If He3 absorbs N and fuses, just have a hotter N, or probably just same (since a good chunk would come from those same D-T) and its a really improbable case, its a small pellet and you can fine tune the temperature (YEA,  efficiency? Who cares! XD) the only primary reactions are D-He3, secondary He3-He3 (and small traces of non burned, He3 cat D-D, but almost negligible) and thertiary D-T traces, same as D-D and He3-T, and thats where most of that 1% comes

In fact He3+He3-D fusion (I call it like this, dont know if has a name) is as clean as H-B, accounting for sider reactions (take that, H-B fans! Now is almost useless except for cheap :P)

Edited by AntaresMC
In the name of accuracy and bit of grammar

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On 5/18/2020 at 9:54 PM, AntaresMC said:

It works, thats evidence that we have to work with, the best thing I can think of to explain it is that the tanks being so obscenely heavy is because the kerbals are quite OCD with boiloffs and its all thermal insulation and some PV paint to power pelters. Any better thoughts that dont rule out  canon, gameplay proof?

Oh I have waay too many mods to consider any gameplay canon. It's all in what one personally wants to handwave, really.

I know I'd never use LF for a NERVA in *my* game, but if I did I'd have to imagine it has a small refinery built in to process hydrogen out of the kerosene...

;)

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Posted (edited)
18 minutes ago, Mandella said:

Oh I have waay too many mods to consider any gameplay canon. It's all in what one personally wants to handwave, really.

I know I'd never use LF for a NERVA in *my* game, but if I did I'd have to imagine it has a small refinery built in to process hydrogen out of the kerosene...

;)

WHAT? Did you say its a mix? LoL, thats very kerbal and would explain most things if you assume its a variable mix. I can assume it for the canon, but coesnt help me I started all of this for my mods, I use KSPIE and USI, and MKS uses a lot of LF-O that IE dont support, FreeThinker says its so magical/unknown, so I have to make an ISRU for IE, because its engines are far superior an another for LFO, because I like logistics and some parts of the production chains require it. I neither, usually use H2/He, but not because of realism/logic, just theg are vastly superior.

Did you really think I play vanilla after having a proposition of Neutronium fuel/isru/engine? Really? :P

Edited by AntaresMC
Sorry was in other thread, just see my first posts to find it

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Posted (edited)
On 5/13/2020 at 7:36 PM, FreeThinker said:

exactly where did you get this number from?

according to this document, iso will not be higher than 211s

 

that numbuer just some theoretically Max,like that LOX/ LH 2 Rocket Combustion in chemical equilibrium can get 510s + at max 100% Eff

Sorry I dont make that clear:blush:

v2-bfcdfb71a71eb81e38946a0fbee343fc_720w

pic from :https://zhuanlan.zhihu.com/p/67562119

I just look again, it a Solid CO Mix LOX, thing might get different

 

Edited by Sweetie bot
Add pic, review

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7 hours ago, Sweetie bot said:

that numbuer just some theoretically Max,like that LOX/ LH 2 Rocket Combustion in chemical equilibrium can get 510s + at max 100% Eff

Sorry I dont make that clear:blush:

https://zhuanlan.zhihu.com/p/67562119

Number from here, might be new ,but lack some ref

We theoretically can get up to around 600 with a FFSC HydroLiFluor 9f rotating detonation in perfect conditions with perfect nozzle. I doubt the real engine would get more than 500 and 5s (you know, Isp and lifetime...)

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@FreeThinker

I've been playing around with Mk2 Expansion lately, and it gave me an idea...

What if we could have some Thermal Rockets and Thermal Turbojets in Mk2 form-factor?

After all, the original source of the idea for the Microwave Beamed Power in the mod was probably the plans of the New Space startup Escape Dynamics (which, sadly, eventually went under), which basically seems to have planned on using a lifting-body spaceplane with a form similar to the Mk2 fuselage (with minimal, highly-swept wings), stuffed to the brim with Liquid Hydrogen, in order to provide more absorptive area for the microwave thermal receivers vs. a cylindrical fuselage (the entire bottom of the spaceplane was basically one giant Microwave Thermal Receiver, if I recall...)

This also provides more Lift, and better aerodynamics, for a lifting-ascent: which they seemed to have opted for as it:

(1) Allowed for the spaceplane to spiral upwards over the Microwave Transmitter site for a while as it gained altitude (to reduce transmission distances), and then set up a run for speed and altitude starting up-range of the transmitters once they got as far as they could in a constant spiral (again, the goal seemed to be to reduce distances so the Thermal Receiver got as much focused power, and time to reach orbit, as possible with just one or two beamed power array hround stations...)

(2) A lifting-ascent allowed the spaceplane to reach orbit with less Thrust than a comparable-payload rocket: which was critical as the most expensive component of the entire system was the beamed-power ground station transceiver arrays (with costs scaling proportional to how much power they had to aim towards the spacecraft...)

All of this translates fairly well to KSP-I, actually: which is part of the reason I discussed it here (all of these ideas work in KSP.  Even the increased receiver-area of the lifting-body form factor: if you use a Mk2 Bicoupler to put two 1.25 meter thermal receivers on the bottom of your spaceplane right now...)

It really would be nice to see some Mk2 form-factor parts in KSP-I (especially the Microwave Beamed Power systems: which are one of the first really powerful KSP-I launch systems you reach in the Community Tech Tree...)

Given how much there is to add there, especially with more aerodynamic parts and the Microwave Beamed Power system needing a little love, maybe it would be best to split KSP-Interstellar into a bundle of related mods, much like NearFuture does?

Would make things more manageable for players: instead of one colossal mod, they could pick-and-choosr different mods in the pack with self-explanatory names: i.e. one for atmospheric parts, including Thermal Turbojets; one for ISRU and resource systems including the Propulsive Fluid Accumulators; one for Microwave Beamed Power; one for the nuclear reactors- which players might want on their own just for electricity generation; one for the plasma thrusters and other related electric propulsion systens; one for the really advanced nuclear propulsion systems; and one for the Warp Drive itself.  Of course, all of these are complementary- and it might be best to keep a centralized wiki/documentation (only split into sub-sections for each mod, so players can find what they're looking for).

Just an idea, anyways.  Might also make it easier to branch/fork off some parts of the mod to different authors too, so you  can focus better on the remaining parts.

Might be a terrible idea too: if it doesn't work well for your authorship style.

Whatever works for you FreeThinker: this continues to become an ever more impressive mod, that amazes me every day: and I'm glad of any part I had in helping you develop it (I think my username is even still found on the authors of a few configs I helped tweak years back, no?), and also importantly: giving you ideas along the way...

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47 minutes ago, Northstar1989 said:

@FreeThinker

I've been playing around with Mk2 Expansion lately, and it gave me an idea...

What if we could have some Thermal Rockets and Thermal Turbojets in Mk2 form-factor?

After all, the original source of the idea for the Microwave Beamed Power in the mod was probably the plans of the New Space startup Escape Dynamics (which, sadly, eventually went under), which basically seems to have planned on using a lifting-body spaceplane with a form similar to the Mk2 fuselage (with minimal, highly-swept wings), stuffed to the brim with Liquid Hydrogen, in order to provide more absorptive area for the microwave thermal receivers vs. a cylindrical fuselage (the entire bottom of the spaceplane was basically one giant Microwave Thermal Receiver, if I recall...)

This also provides more Lift, and better aerodynamics, for a lifting-ascent: which they seemed to have opted for as it:

(1) Allowed for the spaceplane to spiral upwards over the Microwave Transmitter site for a while as it gained altitude (to reduce transmission distances), and then set up a run for speed and altitude starting up-range of the transmitters once they got as far as they could in a constant spiral (again, the goal seemed to be to reduce distances so the Thermal Receiver got as much focused power, and time to reach orbit, as possible with just one or two beamed power array hround stations...)

(2) A lifting-ascent allowed the spaceplane to reach orbit with less Thrust than a comparable-payload rocket: which was critical as the most expensive component of the entire system was the beamed-power ground station transceiver arrays (with costs scaling proportional to how much power they had to aim towards the spacecraft...)

All of this translates fairly well to KSP-I, actually: which is part of the reason I discussed it here (all of these ideas work in KSP.  Even the increased receiver-area of the lifting-body form factor: if you use a Mk2 Bicoupler to put two 1.25 meter thermal receivers on the bottom of your spaceplane right now...)

It really would be nice to see some Mk2 form-factor parts in KSP-I (especially the Microwave Beamed Power systems: which are one of the first really powerful KSP-I launch systems you reach in the Community Tech Tree...)

Given how much there is to add there, especially with more aerodynamic parts and the Microwave Beamed Power system needing a little love, maybe it would be best to split KSP-Interstellar into a bundle of related mods, much like NearFuture does?

Would make things more manageable for players: instead of one colossal mod, they could pick-and-choosr different mods in the pack with self-explanatory names: i.e. one for atmospheric parts, including Thermal Turbojets; one for ISRU and resource systems including the Propulsive Fluid Accumulators; one for Microwave Beamed Power; one for the nuclear reactors- which players might want on their own just for electricity generation; one for the plasma thrusters and other related electric propulsion systens; one for the really advanced nuclear propulsion systems; and one for the Warp Drive itself.  Of course, all of these are complementary- and it might be best to keep a centralized wiki/documentation (only split into sub-sections for each mod, so players can find what they're looking for).

Just an idea, anyways.  Might also make it easier to branch/fork off some parts of the mod to different authors too, so you  can focus better on the remaining parts.

Might be a terrible idea too: if it doesn't work well for your authorship style.

Whatever works for you FreeThinker: this continues to become an ever more impressive mod, that amazes me every day: and I'm glad of any part I had in helping you develop it (I think my username is even still found on the authors of a few configs I helped tweak years back, no?), and also importantly: giving you ideas along the way...

There is actually a MK2 reciever, what Id like is some kind of heat pipe as the ones for fuel that moves from the reactor. That allows to have a mega reactor that splits power over several jets and allows to put adapters in between. They'd be bery heavy and easily breakable. This helps a lot with VTOLs

Also a radially atachable mini thermal jet that vectors a full 90 degrees, allowing for auxiliary control thrusters, VTOLing as well.

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16 minutes ago, AntaresMC said:

There is actually a MK2 reciever, what Id like is some kind of heat pipe as the ones for fuel that moves from the reactor. That allows to have a mega reactor that splits power over several jets and allows to put adapters in between. They'd be bery heavy and easily breakable. This helps a lot with VTOLs

Also a radially atachable mini thermal jet that vectors a full 90 degrees, allowing for auxiliary control thrusters, VTOLing as well.

Oh.  I haven't played with Interstellar in a while, and am just now about to get back into it in my current Career Mode game, having finally advanced through much of the Community Tech Tree- thanks in large part to Covid-19 and finals being over... (on my 2nd of 3 Master's in a dual-degree!)

Does the receiver account for the roll-angle of the spaceplane relative to the vector of the ground station, as it should? (i.e. if you are flying directly overhead, and roll to a 90 degree angle, the Mk2 receiver *should* receive a lot less power, for instance.  Or if you mount the receiver at a 90 degree angle to the normal axis, it should be far less effective for ground stations directly below: but more effective for those off to the side...)

As for heat-pipes from a reactor: that is just ASKING for trouble and an engine-failure, as well as being far harder to realize in real life than you imagine.  Nuclear Thermal Turbo/Ramjets work because the air passes DIRECTLY over a heat-exchanger surface on the surface of the reactor: likely to be made of extremely heat-resistant materials like Quartz, Silicon Carbide, etc.- materials NOT at all flexible or amenable to being used to construct a heat pipe likely to undergo significant structural stresses.  Not to mention the insulation mass-requirements would be high.

Also, the mass requirements of such heat-pipes would scale very non-linearly with increasing amounts of thermal energy transferred (small pipes transferring small amounts of heat would actually be least efficient, whereas larger pipes would have a better ratio of mass to power transferred: although still very poor, and heavy)

You're much better off just using some kind of electric lifting fan (such as the Banshee from either Mk2 Expansion or OPT Spaceplane Parts, I don't recall which) for VTOL: which would actually probably be more energy-efficient in real life, as it takes 4 times the energy to get 2x the Thrust when you double exhaust-velocity (and electric fans have VERY low exhaust velocity.  The downside is you lose Thrust more quickly with increasing speed: but VTOL is almost always done from a standstill anyways...)

If you REALLY want a VTOL using some kind of rocket/thruster, stick small reactors on rotatron parts: so both reactor and thermal turbojet/rocket nozzle move together (having flexible/stretchable air or fuel-ducts that can accommodate this rotation is at least feasible in real-life) OR use a plasma thruster powered by a huge reactor (will reduce fuel-use for VTOL on non-atmospheric planets, but INCREDIBLY energy-inefficient) OR just place a few small fixed-orientation reactor+nozzles inside cargo bays facing down, so they can VTOL when the bay doors are opened...

 

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Posted (edited)

Also, @FreeThinker, do the precoolers still work on a variety of airbreathing engines (not just thermal turbojets) to improve their high-speed, high-altitude performance (as they realistically should: pre-coolong airflow allows the compressors to bring it down to lower speeds and higher pressures without melting themselves in the process!) like I think I remember: or was this functionality stripped from later versions of KSP-Interstellar Extended for some reason?

(A reason such as the whining "realism- it can't be done!" crowd: who are really just a bunch of pessimists who don't even attempt to understand cutting-edge science or what ACTUAL reality entails: i.e. the SABRE pre-cooler was recently PROVEN to work in a hypersonic wind tunnel, and the basic concept of precooling an airflow so you can operate airbreathing engines more effectively at higher speeds/altitudes is sound with regards to basic physics...  The engine doesn't "know" it's in a fast-moving, high-altitude plane if all it sees is air compressed and slowed down to subsonic speeds and sea level pressures, for instance...)

Edited by Northstar1989

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Posted (edited)
1 hour ago, Northstar1989 said:

Does the receiver account for the roll-angle of the spaceplane relative to the vector of the ground station, as it should? (i.e. if you are flying directly overhead, and roll to a 90 degree angle, the Mk2 receiver *should* receive a lot less power, for instance.  Or if you mount the receiver at a 90 degree angle to the normal axis, it should be far less effective for ground stations directly below: but more effective for those off to the side...)

 

Nope, it only counts for cross section, as they "*should*". Effectively is the same.

1 hour ago, Northstar1989 said:

As for heat-pipes from a reactor: that is just ASKING for trouble and an engine-failure, as well as being far harder to realize in real life than you imagine.  Nuclear Thermal Turbo/Ramjets work because the air passes DIRECTLY over a heat-exchanger surface on the surface of the reactor: likely to be made of extremely heat-resistant materials like Quartz, Silicon Carbide, etc.- materials NOT at all flexible or amenable to being used to construct a heat pipe likely to undergo significant structural stresses.  Not to mention the insulation mass-requirements would be high.

Also, the mass requirements of such heat-pipes would scale very non-linearly with increasing amounts of thermal energy transferred (small pipes transferring small amounts of heat would actually be least efficient, whereas larger pipes would have a better ratio of mass to power transferred: although still very poor, and heavy)

 

Yea, but actually no. Its KSP, air (and everything) is teleported from intake to nozzle, fuel pipes are flexible and struts made of adamantium.

Probably one of CNHf alloy with regen coolling would be enough until fusion. Then sorry  not sorry (or mabe a mag tube, but havent developed the idea, quote you when figure out). In real life probably there will be a main reactor and "procedural" nozzles, specificly designed. You can make them heavy and brittle, its OK, I think so, but there is a real penalty for having several small reactors that really breaks VTOLing (will answer the latter later), and weight is a huge concern in an interplanetary VTOL SSTOs, that aint practical until Z-pinch, because its a 1 part solution (and a really overpowered one) and dont have scaling problems.

And yea, may be a good gameplay mechanic that you have to do very soft a plane to not break them, I like it...

2 types, a regular, pipe like, and a big, strut tube like, magnetic. Regenerative cooling and X tansparency, reflective from UV to long IR.

1 hour ago, Northstar1989 said:

You're much better off just using some kind of electric lifting fan (such as the Banshee from either Mk2 Expansion or OPT Spaceplane Parts, I don't recall which) for VTOL: which would actually probably be more energy-efficient in real life, as it takes 4 times the energy to get 2x the Thrust when you double exhaust-velocity (and electric fans have VERY low exhaust velocity.  The downside is you lose Thrust more quickly with increasing speed: but VTOL is almost always done from a standstill anyways...)

If you REALLY want a VTOL using some kind of rocket/thruster, stick small reactors on rotatron parts: so both reactor and thermal turbojet/rocket nozzle move together (having flexible/stretchable air or fuel-ducts that can accommodate this rotation is at least feasible in real-life) OR use a plasma thruster powered by a huge reactor (will reduce fuel-use for VTOL on non-atmospheric planets, but INCREDIBLY energy-inefficient) OR just place a few small fixed-orientation reactor+nozzles inside cargo bays facing down, so they can VTOL when the bay doors are opened...

 

When heavy, long range (aka useful) VTOL SSTOs are concerned, electric engines aint powerful nor power efficient enough, also most dont work usefully in athmo. Also they dont use air. Propellers are dead weight pretty much all time but takeoff, also a huge drag. Numbers dont matchh, and dont say no, Ive also tried. And we need thrust, propellant is free. Plasma? Same, not enough thrust, fuel requirements.

If I can have 2 pelicans, a plasma nozzle, a big central fusion reactor, and can use heat for the pelicans without having stability troubles of only 1 engine, conected by say, a mag tube thats a brittle, heavy structural part with its own heat loses, at say 1.25m. It stil has to be conected by ancor points to the receptor. A low tech version was done with an experiment of a nuke bomber in the US...

For lower core temps, lets say, <5000K you can use a kinda tube as stock ones. Or an alternative cause  having 3 or 4 reactors aint viable nor makes sense...

57 minutes ago, Northstar1989 said:

Also, @FreeThinker, do the precoolers still work on a variety of airbreathing engines (not just thermal turbojets) to improve their high-speed, high-altitude performance (as they realistically should: pre-coolong airflow allows the compressors to bring it down to lower speeds and higher pressures without melting themselves in the process!) like I think I remember: or was this functionality stripped from later versions of KSP-Interstellar Extended for some reason?

(A reason such as the whining "realism- it can't be done!" crowd: who are really just a bunch of pessimists who don't even attempt to understand cutting-edge science or what ACTUAL reality entails: i.e. the SABRE pre-cooler was recently PROVEN to work in a hypersonic wind tunnel, and the basic concept of precooling an airflow so you can operate airbreathing engines more effectively at higher speeds/altitudes is sound with regards to basic physics...  The engine doesn't "know" it's in a fast-moving, high-altitude plane if all it sees is air compressed and slowed down to subsonic speeds and sea level pressures, for instance...)

Yes, they do, and why did you say that realism-weirdo-thinggy? Its realistic and a good (almost necesary), dont think why someone would say against...

Edited by AntaresMC

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8 hours ago, AntaresMC said:

Nope, it only counts for cross section, as they "*should*". Effectively is the same.

Not *quite*.

The microwave beam spreads out as it travels from the transceiver (this effect is worsened by atmosphere in between, as is reflected in the mod) and the larger the transceiver cross-sectional plane *normal to the beam vector*, the larger a % of this power can be captured despite this spread.

If a spaceplane rolls, the cross-section on this plane changes (the Mk2 profile has a smaller cross-section when sliced in a Saggital Plane, than when sliced in a Coronal Plane, to borrow terms from animal anatomy and apply them to the anatomy of spaceplanes...)

This is basic science/math.  I didn't need you to tell me how it works: I already know this for a *fact*, having done much of the research for the original rebalancing of many KSP-I Extended parts with FreeThinker, and read too many articles on Microwave Beamed Power to count...

But what I DON'T know is if the radial asymmetry of the Mk2 transceiver (not around back when I worked on the mod) is correctly accounted for in receiver effectiveness...

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Posted (edited)
8 hours ago, AntaresMC said:

Yea, but actually no. Its KSP, air (and everything) is teleported from intake to nozzle, fuel pipes are flexible and struts made of adamantium.

Some of these are already built into base game, to the point there's no removing them without heavy modding on the scale of Realism Overhaul: but KSP-Interstellar didn't create these issues in the first place.

No reason to add more unrealistic nonsense to the mod by adding a part that is, frankly, near-impossible in the real world, and harder than much of what is already in the mod.

It used to be (correct me if this has changed) that reactors could transfer thermal power to stack-aligned thermal nozzles up to 2 parts away, allowing them to "skip" a single part (or letting you put a reactor on the internal stack node of a cargo bay or fairing, with a nozzle on the rear side).  This was considered a bit of a departure from  realism in itself: as sometimes this could lead to thermal power crossing a single very long part to reach its destination with no added mass required.  But at least this was only a single part, with likely no substantial flexing between the two.

The required equipment would likely involve a very large, heavily-insulated duct: something a lot larger than a mere "pipe", to have sufficient structural strength and insulation to transfer the heat of a reactor (or the superheated gasses) and significant distance, and be able to bend their trajectory.  Magnetic confinement would also be required for thermal levels much over those of a Molten Salt Reactor: so it would be even harder to pipe your heat from fusion/antimatter reactors...  I don't think you would find this of much use in a VTOL engine, even if it were added...

 

Edited by Northstar1989

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Posted (edited)
9 hours ago, AntaresMC said:

When heavy, long range (aka useful) VTOL SSTOs are concerned, electric engines aint powerful nor power efficient enough, also most dont work usefully in athmo. Also they dont use air. Propellers are dead weight pretty much all time but takeoff, also a huge drag. Numbers dont matchh, and dont say no, Ive also tried. And we need thrust, propellant is free. Plasma? Same, not enough thrust, fuel requirements.

If I can have 2 pelicans, a plasma nozzle, a big central fusion reactor, and can use heat for the pelicans without having stability troubles of only 1 engine, conected by say, a mag tube thats a brittle, heavy structural part with its own heat loses, at say 1.25m. It stil has to be conected by ancor points to the receptor. A low tech version was done with an experiment of a nuke bomber in the US...

For lower core temps, lets say, <5000K you can use a kinda tube as stock ones. Or an alternative cause  having 3 or 4 reactors aint viable nor makes sense...

Yes, they do, and why did you say that realism-weirdo-thinggy? Its realistic and a good (almost necesary), dont think why someone would say against...

The beauty of plasma thrusters is their atmospheric ISP actually increases with higher power output.  This is because the Exhaust Pressure goes up and up the more Mass Flow Rate you push through them, and there is less compression of the exhaust stream.  The most critical number is that the exhaust pressure at least equals Ambient Pressure- otherwise in real life there would be invasion of the nozzle area with outside gases, shockwave formation, and collapse of the exhaust stream: with resultant massive loss of Thrust and ISP.

Thermal rocket nozzles used to do the same thing in KSP-Interstellar Extended: this was most noticeable with Microwave Thermal Rickets back in the day- as they had some of the lowest exhaust pressures in the mod at very low power levels: but this could be increased drastically with the same design by adding additional ground-stations transmitting power nearby..

I still remember viewing the Thrust and ISP of a launch clamped thermal rocket, with different numbers of ground stations nearby active/inactivated (each station was basically just a big old Molten Salt Reactor with a Microwave Transceiver/Transmitter) to test that this feature was working properly, and the Thrust/ISP levels were right...

It worked back then- I assume it still does now (though I have a feeling not many users of this mod concern themselves with mastering Microwave Beamed Power now: being in such a rush to make it to Antimatter Power and other advanced rocketry).  Back then there WERE no reliable, reasonably bug-free mods to go to other star systems though.  Now there are- and players are eager to climb the tech tree and visit the stars: or at least I hope that's whst's going on...

 

As for the ducts: it's up to FreeThinker in the end, but I think a lot more research would be needed into actual engineering documents on nuclear reactors and what's at least theoretically possible with their heat management first.

I will say this, though: it becomes about 100x more realistic if you're willing to suffer a large (like 50%) drop in the "reactor temperature" the nozzles see, due to using a coolant to carry the heat instead of somehow managing it with superheated gasses through long ducts directly.  Which means much lower ISP, lower energy efficiency, but actually somewhat better Thrust output for the amount of power consumed...  Also, the max temperature this could transmit would be pretty much s hard ceiling based on tech level, not going up no matter how advanced the reactor became...

Fans aren't that draggy, though.  You hide them in a cargo bay until needed, only opening the bay doors (exposing them to Drag) when it's time to fire them.  And the Banshee fans come in inlinevstack-mounted versions that fit right into a Mk2 fuselage: although it does seem to glitch out when quicksaving/loading.

Still, you can run a mindboggling number of electric fans off a single nuclear reactor...

 

P.S. There are some KSP players who will complain about anything, and are eternal pessimists.  My point was that some of them scoff at the idea of pre-coolers even working, or being useful: in fact I got into several bitter disagreements about this in the Science Labs subforum back in the day... (this is before BAE and Reaction Systems finished quietly working on the SABRE precooler and started testing/demonstrating it to prove it to the world...)

Edited by Northstar1989

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5 hours ago, Northstar1989 said:

Not *quite*.

The microwave beam spreads out as it travels from the transceiver (this effect is worsened by atmosphere in between, as is reflected in the mod) and the larger the transceiver cross-sectional plane *normal to the beam vector*, the larger a % of this power can be captured despite this spread.

If a spaceplane rolls, the cross-section on this plane changes (the Mk2 profile has a smaller cross-section when sliced in a Saggital Plane, than when sliced in a Coronal Plane, to borrow terms from animal anatomy and apply them to the anatomy of spaceplanes...)

This is basic science/math.  I didn't need you to tell me how it works: I already know this for a *fact*, having done much of the research for the original rebalancing of many KSP-I Extended parts with FreeThinker, and read too many articles on Microwave Beamed Power to count...

But what I DON'T know is if the radial asymmetry of the Mk2 transceiver (not around back when I worked on the mod) is correctly accounted for in receiver effectiveness...

THATS WHAT I SAID!!!

What I said is that no matter the AoA, the cross section is what matters

5 hours ago, Northstar1989 said:

Some of these are already built into base game, to the point there's no removing them without heavy modding on the scale of Realism Overhaul: but KSP-Interstellar didn't create these issues in the first place.

No reason to add more unrealistic nonsense to the mod by adding a part that is, frankly, near-impossible in the real world, and harder than much of what is already in the mod.

It used to be (correct me if this has changed) that reactors could transfer thermal power to stack-aligned thermal nozzles up to 2 parts away, allowing them to "skip" a single part (or letting you put a reactor on the internal stack node of a cargo bay or fairing, with a nozzle on the rear side).  This was considered a bit of a departure from  realism in itself: as sometimes this could lead to thermal power crossing a single very long part to reach its destination with no added mass required.  But at least this was only a single part, with likely no substantial flexing between the two.

The required equipment would likely involve a very large, heavily-insulated duct: something a lot larger than a mere "pipe", to have sufficient structural strength and insulation to transfer the heat of a reactor (or the superheated gasses) and significant distance, and be able to bend their trajectory.  Magnetic confinement would also be required for thermal levels much over those of a Molten Salt Reactor: so it would be even harder to pipe your heat from fusion/antimatter reactors...  I don't think you would find this of much use in a VTOL engine, even if it were added...

 

How did you think radiators work?

No, if it isnt directly attached, dont work, and thats the main problem...

For AM reactors and advenced fusion, I let it go. But for early fusion and fission, systems like this have been proposed for HSP power plants.

And who said light, long and strong? The challenge of be brittle in exchange of not havong the weight of an entire new reactor is worth it.

And who said all the reactor's power? Mass flow limited, obvious. And heat loses with distance...

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5 hours ago, Northstar1989 said:

The beauty of plasma thrusters is their atmospheric ISP actually increases with higher power output.  This is because the Exhaust Pressure goes up and up the more Mass Flow Rate you push through them, and there is less compression of the exhaust stream.  The most critical number is that the exhaust pressure at least equals Ambient Pressure- otherwise in real life there would be invasion of the nozzle area with outside gases, shockwave formation, and collapse of the exhaust stream: with resultant massive loss of Thrust and ISP.

Thermal rocket nozzles used to do the same thing in KSP-Interstellar Extended: this was most noticeable with Microwave Thermal Rickets back in the day- as they had some of the lowest exhaust pressures in the mod at very low power levels: but this could be increased drastically with the same design by adding additional ground-stations transmitting power nearby..

I still remember viewing the Thrust and ISP of a launch clamped thermal rocket, with different numbers of ground stations nearby active/inactivated (each station was basically just a big old Molten Salt Reactor with a Microwave Transceiver/Transmitter) to test that this feature was working properly, and the Thrust/ISP levels were right...

It worked back then- I assume it still does now (though I have a feeling not many users of this mod concern themselves with mastering Microwave Beamed Power now: being in such a rush to make it to Antimatter Power and other advanced rocketry).  Back then there WERE no reliable, reasonably bug-free mods to go to other star systems though.  Now there are- and players are eager to climb the tech tree and visit the stars: or at least I hope that's whst's going on...

 

As for the ducts: it's up to FreeThinker in the end, but I think a lot more research would be needed into actual engineering documents on nuclear reactors and what's at least theoretically possible with their heat management first.

I will say this, though: it becomes about 100x more realistic if you're willing to suffer a large (like 50%) drop in the "reactor temperature" the nozzles see, due to using a coolant to carry the heat instead of somehow managing it with superheated gasses through long ducts directly.  Which means much lower ISP, lower energy efficiency, but actually somewhat better Thrust output for the amount of power consumed...  Also, the max temperature this could transmit would be pretty much s hard ceiling based on tech level, not going up no matter how advanced the reactor became...

Fans aren't that draggy, though.  You hide them in a cargo bay until needed, only opening the bay doors (exposing them to Drag) when it's time to fire them.  And the Banshee fans come in inlinevstack-mounted versions that fit right into a Mk2 fuselage: although it does seem to glitch out when quicksaving/loading.

Still, you can run a mindboggling number of electric fans off a single nuclear reactor...

 

P.S. There are some KSP players who will complain about anything, and are eternal pessimists.  My point was that some of them scoff at the idea of pre-coolers even working, or being useful: in fact I got into several bitter disagreements about this in the Science Labs subforum back in the day... (this is before BAE and Reaction Systems finished quietly working on the SABRE precooler and started testing/demonstrating it to prove it to the world...)

I know how plasma nozzles work. And Im quite upset that thermal nozzles dont have Isp curve :/

Beam power is still needed, used and the best thing in the world. If you tech rush to AM, will get stuck, but its true that there are alts. A good chunk dont use'em because is overly realistc, aka complicated and dont know how to. Just google KSPIE, there are just BP tutorials...

Of course, I agree in most of that limitations. In fact, if just added a thermal ducted adapter, and a multi cupler, Id be OK...

And you can be creative, for example  once in space you can use an open railgun...

And fans ARE draggy. And if you have them in a bay wont get enough air to play with, its equally unrealistic... And generate heat, to eletcricity, to fans is just a full auto AFK 0tick WasteHeat farm, and much less efficient thant0 thermal. And they take more and more power the hotter they are. And still dead weight all time but takeoff. 

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4 hours ago, AntaresMC said:

 Im quite upset that thermal nozzles dont have Isp curve :/

They do.  That was what I was just describing.

Atmospheric ISP is a function of both the type of propellant being used, and the throttle/power levels.  In real life, ISP does *NOT* remain constant as you throttle down, like it does in KSP (decreased exhaust pressure leads to a worse ratio between exhaust pressure and ambient pressure: decreasing ISP).

ISP curves, as they exist in KSP, bear little resemblance to real life.  They bore even less in the past-m: where ISP changed but Thrust remained constant with different ambient pressures in earlier versions of KSP...

Interstellar was ahead of the curve, by setting Thrust and ISP to vary together at a constant Mass Flow Rate, like they do in real life.  Throttle/Power also affects ISP, though, and this was reflected in Interstellar better than it was in Stock...

The ISP you get varies based on which nozzle you choose.  I don't know if you noticed this before, but (unless this was changed) you used to get better ISP when using nozzle sizes smaller than the reactor size when you were thrusting in the atmosphere with a relatively weak engine (due to not over-expanding the exhaust stream).  There was talk about adding more customization of nozzle sizes/shapes, but ultimately that was never realized...

 

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7 hours ago, Northstar1989 said:

They do.  That was what I was just describing.

Atmospheric ISP is a function of both the type of propellant being used, and the throttle/power levels.  In real life, ISP does *NOT* remain constant as you throttle down, like it does in KSP (decreased exhaust pressure leads to a worse ratio between exhaust pressure and ambient pressure: decreasing ISP).

ISP curves, as they exist in KSP, bear little resemblance to real life.  They bore even less in the past-m: where ISP changed but Thrust remained constant with different ambient pressures in earlier versions of KSP...

Interstellar was ahead of the curve, by setting Thrust and ISP to vary together at a constant Mass Flow Rate, like they do in real life.  Throttle/Power also affects ISP, though, and this was reflected in Interstellar better than it was in Stock...

The ISP you get varies based on which nozzle you choose.  I don't know if you noticed this before, but (unless this was changed) you used to get better ISP when using nozzle sizes smaller than the reactor size when you were thrusting in the atmosphere with a relatively weak engine (due to not over-expanding the exhaust stream).  There was talk about adding more customization of nozzle sizes/shapes, but ultimately that was never realized...

 

So I have it badly installed? I dont think @FreeThinker would remove this feature... nor why...

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Posted (edited)
18 hours ago, AntaresMC said:

So I have it badly installed? I dont think @FreeThinker would remove this feature... nor why...

To simplify things probably.  Or maybe I am misremembering- and this feature was never made a part of the mod in the first place (and I am remembering testing revised ISP curves for different propellants in-atmosphere: as they end up with very different exhaust pressures for the same Thermal Power..)

But do me a favor, alright: actually test this for yourself by pad-testing a variety of different thermal rockets (both nuclear thermal and microwave thermal) with different ThernalPower ratings but the SAME core temperatures, and different Thermal Nozzle sizes in relation to the reactors, and post Imgur albums of the rocket nozzle and reactor/thermal receiver context (right-click) menus during static thrusting on the pad here, so all of us can see, and can critique whether it's working properly.

Posting images of the same combinations in orbit (just cheat-menu them there, or Hyperedit if you use it) will also help verify if the atmospheric Thrust/ISP's don't drop as much as expected, or drop too much...

If the ISP/Thrust numbers aren't what would be expected for reactors/nozzles of those size and fuel types, I can advise FreeThinker on what numbers would be more realistic to incorporate into the mod (or at least point him towards some resources) and you might get your ISP curves after all, if they weren't already there!

 

Regards,

Northstar

Edited by Northstar1989

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