KSP Interstellar Extended Support Thread

[BlackMoons]

5 minutes ago, ArmchairPhysicist said:

I have a question regarding the space plane parts.

I just unlocked both the thermal ramjet/turbojet node, and the thermal launch nozzle, but neither have been much use to my aviation division. What purpose where these engines built for? I'm sure they have some niche job, but I'm having trouble justifying the ssto research if my rockets work way better.

Generally, beamed power and getting thrust outta reactors.

The thermal Ramjet can for example switch over to propellants, so you can get free reaction mass to 20KM, then switch over to propellants at something crazy like 500~1000ISP depending on mated reactor core temps.

Beamed power lets you put the reactors at KSC so much higher TWR but only works near the reactors (depending on beamed power tech and relays)

Reactors are heavy and anything but the timberwind or antimatter power generally won't result in SSTO AFAIK. a couple GW of beamed power though can lift 100ton payloads to geosync orbit in a SSTO though.

Edited July 23, 2017 by BlackMoons

[ArmchairPhysicist]

Just now, BlackMoons said:

Generally, beamed power and getting thrust outta reactors.

The thermal Ramjet can for example switch over to propellants, so you can get free reaction mass to 20KM, then switch over to propellants at something crazy like 500~1000ISP depending on mated reactor core temps.

Beamed power lets you put the reactors at KSC so much higher TWR but only works near the reactors (depending on beamed power tech and relays)

Silly me, I completely forgot about beamed thermal power, I'll give it a try.

[BlackMoons]

12 minutes ago, ArmchairPhysicist said:

Silly me, I completely forgot about beamed thermal power, I'll give it a try.

Yea, Id aim for at least 4GW of beamed power at reception as a test. That is like 6~7GW of actual power generation.

I think you can start getting mainsail kinda power outta that if you use the thermal launch nozzle and liquid+oxidiser.

Liquid only gives you much better ISP but 1/2 as much power or so. (But then you can just beam moah power for more thrust)

[Ciro1983811]

On 1/7/2017 at 11:14 PM, FreeThinker said:

@trias702  First you need to understand that if a reactor producing both charged particles and thermal heat, a thermal generator will use the power of both types in the correct fraction

Another thing you need to understand that for electric power production an antimatter reactor is limited to 5% power production, only direct charged particle propulsion with a magnetic nozzle can unleash the full power potential

Now to understand power output, you need to understand it tries to match with requested power, which is 34.9 MW for  the Vasimr + 160 KW for Antimatter storage

THe final power output is calculated by simply add up both energy outputs and multiply by efficiency (9.25 MW + 51.6 MW ) * 57.52 = +/-35 MW

 But  the 76.5 Mw number appears to be wrong, the correct number would be 46.7 MW (at maximum efficiency of 65% )

 

electric power production for antimatter reactor is limited to 5% of full power. The only way to use the full power is to couple with magnetic nozzle to redirect charged particles directly out of reactor to thrust. That's because extreme temperature, velocity  and type of radiation emitted can't be used by generators.

[DrScarlett]

1 hour ago, BlackMoons said:

Open your reactor control window next screenshot DrScarlett

Done, edited the post

1 hour ago, BlackMoons said:

DrScarlett: Very cheap fix for bug for now: Go into antimatter drives .cfg file and crank the power up 20 fold Then 5% = full stock power.

Naaa, I don't like to muck around with the .cfg's. I'd rather bat my eyelashes @FreeThinker and ask pretty please, could you chalk this one up for the next release? From my perspective even nicer fix than the AM Lab production bug  

Strike that, didn't read @Ciro1983811 yet

@BlackMoons thank you for checking it out!!

Edited July 23, 2017 by DrScarlett

[BlackMoons]

46 minutes ago, Ciro1983811 said:

electric power production for antimatter reactor is limited to 5% of full power. The only way to use the full power is to couple with magnetic nozzle to redirect charged particles directly out of reactor to thrust. That's because extreme temperature, velocity  and type of radiation emitted can't be used by generators.

Well, that really sucks since its not mentioned in the description of that part at all. I thought it would be awesome for electric drives but 5% max output is kinda meh. I mean I guess 30GW outta 16tons isent bad...

Does the quantum Singularity reactor at least output 100% power? Though that thing seems a little OP to me since its fuels are so common..

[Ciro1983811]

Just now, BlackMoons said:

Well, that really sucks since its not mentioned in the description of that part at all. I thought it would be awesome for electric drives but 5% max output is kinda meh. I mean I guess 30GW outta 16tons isent bad...

Does the quantum Singularity reactor at least output 100% power? Though that thing seems a little OP to me since its fuels are so common..

QSR have integrated generator at full conversion. usually for big electric production i use tri alpha scaled up (integrated CP generator) or antimatte rinitiated fusion reactor with both CP generator and thermal generator.

[BlackMoons]

12 minutes ago, Ciro1983811 said:

QSR have integrated generator at full conversion. usually for big electric production i use tri alpha scaled up (integrated CP generator) or antimatte rinitiated fusion reactor with both CP generator and thermal generator.

Good to know the tri-alpha becomes useful.

What fuels do you use for it? Im considering lithium-6 cycle or something since its easy to mine. (once I unlock it anyway)

Or maybe pairing a HE3 using fuel cycle with a smaller cold deuterium (or some other high neutron reaction) fusion powerplant to produce the HE3. (For orbital/moon power generation)

Edited July 23, 2017 by BlackMoons

[DrScarlett]

2 hours ago, Ciro1983811 said:

electric power production for antimatter reactor is limited to 5% of full power. The only way to use the full power is to couple with magnetic nozzle to redirect charged particles directly out of reactor to thrust. That's because extreme temperature, velocity  and type of radiation emitted can't be used by generators.

OK I try that in my medium Alcubierre drive FTL setup. Still gives me the 30GW, enough to run the rig at 20c (20xlightspeed). I do not know yet if that is enough. Looks like I need about 48GW to run at full warp power.

If I replace my Kerbstein with a magnetic nozzle, I get a much lower TWR, which means that when I arrive and drop out of warp, I need hours to break into orbit (depending on my starting vector and the relative vector of the target body). Even though I am using all my particles with the nozzle, I see no advantage for my circumstance.

1 hour ago, Ciro1983811 said:

QSR have integrated generator at full conversion. usually for big electric production i use tri alpha scaled up (integrated CP generator) or antimatte rinitiated fusion reactor with both CP generator and thermal generator.

The Tri-alpha gets me up to 14GW, scaled to 5 meters. Next size tier I need to switch to the big Alcubierre drive so maybe that works, didn't test it. But the 14GW are not enough. Good enough to charge, but not enough to create the warp field. I wouldn't get to the warp speeds the 30GW get me either, even if it does work.

The antimatter initiated reactor (at 3.75 meters) with both generators theoretically gives me some 38 GW, charges up nicely, but warp initiation fails at 35% critical power (not sure how that works, what it means, why the 38 GW do not get me running). Maybe its because of the added mass (156 tons as opposed to the 122 tons of the antimatter drive setup).

Anyway, it looks like the antimatter reactor still has the best electrical power to mass ratio, despite the 5% conversion limitation.

Probably he whole picture changes if I scale up to the large Alcubierre drive and test out all these power setups again. Which kind of makes me think. And ask:

• What electrical power setup for FTL do you guys use in the largest scale (large Alcubierre drive, full warp capability)?
• Is there any way to efficiently power a small craft with a small Alcubierre drive? Hopefully even up to full warp speed?
• What is max warp anyway?
• How is it that going lower than 1c also costs incrementally more power, what is the scientific reasoning behind that?

Edited July 23, 2017 by DrScarlett

[BlackMoons]

Yea im annoyed that engines with insanely high core temps end up with really low TWR. I don't care about 10,000ISP I wanna get there in less then a 2 hour burn.

I havent tried the Kerbstein yet, but give the timberwind a try! Its got some REALLY good TWR even though it *only* has 800isp

Edited July 23, 2017 by BlackMoons

[FreeThinker]

7 hours ago, BlackMoons said:

 but give the timberwind a try! Its got some REALLY good TWR even though it *only* has 800isp

The minimum Isp of the Timberwind on Hydrogen is 939s with a TWR of a chemical rockett, which is still twice as good as any chemical rocket can achieve. That pretty good and won't be match by any other engine  exept animatter. The only way to trump that without antimatter is to use beamed power with thermal receiver, which allows you to achieve even higher TWR than antimatter

[DrScarlett]

42 minutes ago, FreeThinker said:

... exept animatter. The only way to trump that without antimatter... ...even higher TWR than antimatter

When you say antimatter here, which engine are you actually referring to? The magnetic nozzle?

[DrScarlett]

OK then, another win here. YAY! This is the best FTL setup I could find in the small size category. It flies to Jool at 320c in under 10 seconds. I could probably go even MUCH faster (is there a max warp, or is it just dependent on power?) but I was speeding into Jool too fast already...

At this size of craft, the magnetic nozzle gave me a TWR of 2.61, used the full 685 GW of CP, allowing me to break into orbit (over 4K dV) in under 4 minutes.

I havent decided on a planetary expansion pack yet, but I can see this thing explore other star systems as a scouting vessel  Whoohoo!

Now to start exploring the large sized end of the spectrum... See what I can use for the actual colonization wave.

Edited July 24, 2017 by DrScarlett

[FreeThinker]

1 hour ago, DrScarlett said:

When you say antimatter here, which engine are you actually referring to? The magnetic nozzle?

I was referring to a combination of the Mk1 thermal (beamed power) receiver and thermal (launch) nozzle

[DrScarlett]

1 minute ago, FreeThinker said:

I was referring to a combination of the Mk1 thermal (beamed power) receiver and thermal (launch) nozzle

Aah yes, I understand you were mentioning beamed power. Since beamed power is something I would like to stay away from until I know what planetary pack I will be using, I was interested in which engine you were thinking about when you were excluding the TWR of 'antimatter'.

[FreeThinker]

1 minute ago, DrScarlett said:

Aah yes, I understand you were mentioning beamed power. Since beamed power is something I would like to stay away from until I know what planetary pack I will be using, I was interested in which engine you were thinking about when you were excluding the TWR of 'antimatter'.

By antimatter reactor, I refer to the 2 anti matter reactions, the Antimatter Initiated Fusion reaction and the Pure Antimatter reactor.

[DrScarlett]

1 minute ago, FreeThinker said:

By antimatter reactor, I refer to the 2 anti matter reactions, the Antimatter Initiated Fusion reaction and the Pure Antimatter reactor.

Yes, that was also clear to me. But what engine were you thinking about to pair those reactors with in order to get to the TWR in that list of comparisons?

[FreeThinker]

12 minutes ago, DrScarlett said:

Yes, that was also clear to me. But what engine were you thinking about to pair those reactors with in order to get to the TWR in that list of comparisons?

A thermal nozzle, which can be a thermal launch nozzle, a thermal turbojet nozzle or thermal ramjet nozzle, depending on your vessel configuration

[DrScarlett]

Thank you, @FreeThinker,

that is a very interesting option. When putting that on the small FTL craft above it gives great TWR, and gets me off the launchpad to boot! I just need to balance out the amount of LH2 I pack to have enough dV to break at the target and break again on the return after the FTL hops. I have too much mass for crazy light speeds (a "mere" 50c in this example), but for jumping around the Kerbal system, it's great!

Thanks again for that pointer!

EDIT: AUWCH, I needed 14K dV to break on the return to Kerbin, only had 4.7K left. Say bye-bye to the Kerbal system  - back to the drawing board on this one, hehehe. That balance act is not as easy as I thought.

EDIT2: Nope, can't pack enough dV to stay under the light Alcubierre drive mass limit. Not enough to still have a safe return trip breaking margin.Guess I will have to stick with the magnetic nozzle, also for system hops (and get that into space on a separate chemical launch stage). Something to be said for high ISP after all  I am starting to dig this after all this experimentation.

 

Edited July 24, 2017 by DrScarlett

[DrScarlett]

So all this playing around brings me to yet another question:

When doing Alcubierre FTL hops, and you know your target and want to do a return trip as well, is there a way to predict how much dV you will need on each of the capture breaking maneuvers?

[Ciro1983811]

13 hours ago, BlackMoons said:

Good to know the tri-alpha becomes useful.

What fuels do you use for it? Im considering lithium-6 cycle or something since its easy to mine. (once I unlock it anyway)

Or maybe pairing a HE3 using fuel cycle with a smaller cold deuterium (or some other high neutron reaction) fusion powerplant to produce the HE3. (For orbital/moon power generation)

Litium Hydride ... same as Kerbstein! One IFS Cargo tank to feed them all !! hehehe

Note that coupling kerbstein with same size tri-alpha it's the best combination. kerbstein utilize 90% of energy produced by trialha, and trialpha integrated generator has >90% efficiency... so you can use simply 4 skin graphene radiators and that's all.

 

Forr SSTW (single stage to warp) i usually utilize 2 or 3 antimatter reactor coupled with thermal turbjets and CP generators for high thrust atmo and ammonia/methane (isru dependant) for higher atmo in closed cicle mode. Then over 40Km high, fire kerbstein/trialpha and go (antimatter off). When charging and utilizing warp drive, trialpha work at full load and the CP generators on the antimatters do the rest (and there you'll need a bit more radiator capacity).

[BlackMoons]

2 hours ago, DrScarlett said:

So all this playing around brings me to yet another question:

When doing Alcubierre FTL hops, and you know your target and want to do a return trip as well, is there a way to predict how much dV you will need on each of the capture breaking maneuvers?

None? Just use gravity braking? (repeatly warp closer to the planet so its gravity slows you down?)

[DrScarlett]

7 minutes ago, BlackMoons said:

None? Just use gravity braking? (repeatly warp closer to the planet so its gravity slows you down?)

Scuse me??? Got any vids or any place I can find details on that?

EDIT: Never heard of that! Tried a bit of stutter stepping towards the planet myself, but only saw a small drop in the dV needed for orbit, so I left it. If this technique is legit I need to learn it. Thanks for bringing it up!

Edited July 24, 2017 by DrScarlett

[FreeThinker]

2 hours ago, DrScarlett said:

So all this playing around brings me to yet another question:

When doing Alcubierre FTL hops, and you know your target and want to do a return trip as well, is there a way to predict how much dV you will need on each of the capture breaking maneuvers?

In theory none at all, the trick is to understand your vector in the galaxy and the velocity you need to stay in orbit around a celestial body., then it just a matter of flying close enough to your target and drop out of warp at the right moment, which becomes easier the slower you go. Your exit speed is visible in the Aclubier Warp control window, use it wisely

Edited July 24, 2017 by FreeThinker

[BlackMoons]

2 minutes ago, FreeThinker said:

In theory none at all, the trick is to understand your vector in the galaxy and the velocity you need to stay in orbit around a celestial body., then it just a matter of flying close enough to your target and drop out of warp at the right moment, which becomes easier the slower you go.

Yea, and for example you can start + or - 2000m/s by picking what part of the orbit around kerbin you start from. Or get a higher orbit and start with +- less velocity.