FreeThinker

[1.8.1, 1.7.3/1.6.1/1.5.1/1.4.5/1.3.1] KSP Interstellar Extended 1.23.8 Support Thread

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12 minutes ago, DrScarlett said:

No. Neither. You want to drop out of warp so that your retained vector becomes your orbital vector.

oh... ok, that makes sense.. so i'm not necessarily always going right at the planet (or away from it) but i... wait, yes I do, but my exit vector might be perpendicular to the warp-approach vector... ok.

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1 minute ago, ss8913 said:

.. wait, yes I do, but my exit vector might be perpendicular to the warp-approach vector...

Exactly! So it is very good to know what this vector is :) @FreeThinker do you think you might come up with a way to visualise your exit vector without having to drop out of warp?

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7 hours ago, DrScarlett said:

Exactly! So it is very good to know what this vector is :) @FreeThinker do you think you might come up with a way to visualise your exit vector without having to drop out of warp?

I tried, I have been unsuccessful. There is no easy solution, they made it really hard.

7 hours ago, ss8913 said:

oh... ok, that makes sense.. so i'm not necessarily always going right at the planet (or away from it) but i... wait, yes I do, but my exit vector might be perpendicular to the warp-approach vector... ok.

Hint: watch your closest approach (periapsis) after you drop out of warp, this is the location you should have aimed for to get in perfect circular orbit. It's usually easier to make a detour instead of trying to manoeuvre around the planet while in the gravity well because, at low warp speed, orbit becomes curved as well.

Edited by FreeThinker

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12 hours ago, FreeThinker said:

Let's make a short testing trip

SNXHcPE.png

gPKUQjL.png

ligansp.png

DH7N30B.png

c2xI1FR.png

Final orbit after dropping out of warp. I slightly overshot my intended target. Still, I need 391 m/s delta V to get in perfect circular orbit, which is a big difference without gravity breaking

Yep!!! That's very easyer to understand when to drop out of warp and how much dV we will need. And also, eccentricity <1 means that you will exit captured in orbit of target (not circular but you will not drift away at least).

 

Good! Please give us an alpha or beta to play with! Nice job!

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56 minutes ago, Ciro1983811 said:

Yep!!! That's very easyer to understand when to drop out of warp and how much dV we will need. And also, eccentricity <1 means that you will exit captured in orbit of target (not circular but you will not drift away at least).

 

Good! Please give us an alpha or beta to play with! Nice job!

Yes it will, and I think adding the exit Eccentric anomaly would be useful as well, as it tells you if you have drop out of warp the left or right of a planet 

figure1.jpg

Edited by FreeThinker

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1 minute ago, FreeThinker said:

I think adding the exit Eccentric anomaly would be useful, as it tells you if you have drop out the left or right of a planet 

I think adding the exit Eccentric anomaly would be useful, as it tells you if you have drop out the left or right of a planet 

Yes, but make it of simple understandig, like " mean anomaly and the a statement like: "Exit in prograde orbit, or exit in retrograde orbit... something that people can undertand even without knowing what is the mean anomaly!

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3 minutes ago, Ciro1983811 said:

Yes, but make it of simple understandig, like " mean anomaly and the a statement like: "Exit in prograde orbit, or exit in retrograde orbit... something that people can undertand even without knowing what is the mean anomaly!

Alright, How should I call my fields then? and it what order?

Edited by FreeThinker

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22 minutes ago, FreeThinker said:

Alright, How should I call my fields then? and it what order?

mmmh. ...

hehehe ...

 

I suggest something like this:

Exit speed: readout

Exit eccentricity : readout and then if >1 "IPERBOLIC NOT CAPTURED"  0<ecc>1 "ELLIPTIC CAPTURED", =0 "CIRCULAR" <0 suborbital

Exit dV to circularize: readout

Exit mean anomaly: readout and direction needed to maximize gravity breack effect hdg and pitch (maybe and that would be wonderful, indicating it in blue marker maneuver node targeting on navball!!!)

Edited by Ciro1983811

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7 minutes ago, Ciro1983811 said:

Exit mean anomaly: readout and direction needed to maximize gravity breack effect hdg and pitch (maybe and that would be wonderful, indicating it in blue marker maneuver node targeting on navball!!!)

5

putting a markers on the navbal durring warp is an interesting idea

Edited by FreeThinker

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11 minutes ago, FreeThinker said:

putting a markers on the navbal durring warp is an interesting idea

Yeah that will become really user friendly and give you actually something to do and care about during warp transfers. Miss the right spot and yo'll have to do some sort of jump back and try again, or spend a lot of dV ... that's great!

 

Speaking about something else, i was reading project rho engine list... i think Dr.Zubrin Nuclear Salt water engine should be added as a mid career standalone high trust mid isp long trips engine... 

The fuel is a 2% solution of 20% enriched Uranium Tetrabromide in water (90% enriched weapon grade uranium could be also used, reducing fuel flow an concentration in water). 

The fuel tanks are a bundle of pipes coated with a layer of boron carbide neutron damper. The damper prevents a chain reaction. The fuel is injected into a long cylindrical plenum pipe of large diameter, which terminates in a rocket nozzle. Free of the neutron damper when out of the fuel tank, a critical mass of uranium soon develops. The energy release vaporizes the water, and the blast of steam carries the still reacting uranium out the nozzle.

 

NSWR.jpg

 

Assume a nozzle efficiency of 0.8, and the result is an exhaust velocity of 66,000 m/s or a specific impules of 6,7300 seconds. The total jet power is 427 gigawatts. The thrust is 12.9 meganewtons. The thrust-to-weight ratio will be about 40, which implies an engine mass of about 33 metric tons.

For exponetial detonation, kz has to be about 4 at the plenum exit. Since k = 0.062 cm-1, the plenum will have to be 65 cm long. The plenum will be 65 cm long with a 3.075 cm radius, plus an exhaust nozzle.

Zubrin then goes on to speculate about a more advanced version of the NSWR, suitable for insterstellar travel. Say that the 2% uranium bromide solution used uranium enriched to 90% U235 instead of only 20%. Assume that the fission yield was 90% instead of 0.1%. And assume a nozzle efficency of 0.9 instead of 0.8.

That would result in an exhaust velocity of a whopping 4,725,000 m/s (about 1.575% c, a specific impulse of 482,140 seconds). In a ship with a mass ratio of 10, it would have a delta V of 3.63% c. 

 

That's a quasi-interstella engine on fission .... mid tech tree...

 

 

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28 minutes ago, FreeThinker said:

putting a markers on the navbal durring warp is an interesting idea

Indeed!

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22 minutes ago, Ciro1983811 said:

Speaking about something else, i was reading project rho engine list... i think Dr.Zubrin Nuclear Salt water engine should be added as a mid career standalone high trust mid isp long trips engine... 

The fuel is a 2% solution of 20% enriched Uranium Tetrabromide in water (90% enriched weapon grade uranium could be also used, reducing fuel flow an concentration in water). 

The fuel tanks are a bundle of pipes coated with a layer of boron carbide neutron damper. The damper prevents a chain reaction. The fuel is injected into a long cylindrical plenum pipe of large diameter, which terminates in a rocket nozzle. Free of the neutron damper when out of the fuel tank, a critical mass of uranium soon develops. The energy release vaporizes the water, and the blast of steam carries the still reacting uranium out the nozzle.

Assume a nozzle efficiency of 0.8, and the result is an exhaust velocity of 66,000 m/s or a specific impules of 6,7300 seconds. The total jet power is 427 gigawatts. The thrust is 12.9 meganewtons. The thrust-to-weight ratio will be about 40, which implies an engine mass of about 33 metric tons.

For exponetial detonation, kz has to be about 4 at the plenum exit. Since k = 0.062 cm-1, the plenum will have to be 65 cm long. The plenum will be 65 cm long with a 3.075 cm radius, plus an exhaust nozzle.

Zubrin then goes on to speculate about a more advanced version of the NSWR, suitable for insterstellar travel. Say that the 2% uranium bromide solution used uranium enriched to 90% U235 instead of only 20%. Assume that the fission yield was 90% instead of 0.1%. And assume a nozzle efficency of 0.9 instead of 0.8.

That would result in an exhaust velocity of a whopping 4,725,000 m/s (about 1.575% c, a specific impulse of 482,140 seconds). In a ship with a mass ratio of 10, it would have a delta V of 3.63% c.

That's a quasi-interstella engine on fission .... mid tech tree...

11

Well if I can get access to a believable NSWE engine model, I would add it

Edited by FreeThinker

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Just now, FreeThinker said:

Well if I can get access to a believable NSWE engine model, I would add it

You will have also to make a fuelswitch setup for the nuclear fuel tank that allow Ubr4 storage, with a very high dry mass (the pipes bundle of boron carbide) and made it mandatory that the tank have to be directly above the engine (otherwise, no moderator in UBr4 solution means starting a chain fission reaction...kaboom)

 

@FreeThinker, somebody here on forum is trying to develope one, and made some models:

 

Try to contact him!

 

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2 hours ago, Ciro1983811 said:

Yeah that will become really user friendly and give you actually something to do and care about during warp transfers. Miss the right spot and yo'll have to do some sort of jump back and try again, or spend a lot of dV ... that's great!

 

Speaking about something else, i was reading project rho engine list... i think Dr.Zubrin Nuclear Salt water engine should be added as a mid career standalone high trust mid isp long trips engine... 

The fuel is a 2% solution of 20% enriched Uranium Tetrabromide in water (90% enriched weapon grade uranium could be also used, reducing fuel flow an concentration in water). 

The fuel tanks are a bundle of pipes coated with a layer of boron carbide neutron damper. The damper prevents a chain reaction. The fuel is injected into a long cylindrical plenum pipe of large diameter, which terminates in a rocket nozzle. Free of the neutron damper when out of the fuel tank, a critical mass of uranium soon develops. The energy release vaporizes the water, and the blast of steam carries the still reacting uranium out the nozzle.

 

NSWR.jpg

 

Assume a nozzle efficiency of 0.8, and the result is an exhaust velocity of 66,000 m/s or a specific impules of 6,7300 seconds. The total jet power is 427 gigawatts. The thrust is 12.9 meganewtons. The thrust-to-weight ratio will be about 40, which implies an engine mass of about 33 metric tons.

For exponetial detonation, kz has to be about 4 at the plenum exit. Since k = 0.062 cm-1, the plenum will have to be 65 cm long. The plenum will be 65 cm long with a 3.075 cm radius, plus an exhaust nozzle.

Zubrin then goes on to speculate about a more advanced version of the NSWR, suitable for insterstellar travel. Say that the 2% uranium bromide solution used uranium enriched to 90% U235 instead of only 20%. Assume that the fission yield was 90% instead of 0.1%. And assume a nozzle efficency of 0.9 instead of 0.8.

That would result in an exhaust velocity of a whopping 4,725,000 m/s (about 1.575% c, a specific impulse of 482,140 seconds). In a ship with a mass ratio of 10, it would have a delta V of 3.63% c. 

 

That's a quasi-interstella engine on fission .... mid tech tree...

 

 

With those numbers how does the reaction chamber avoid melting?

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2 minutes ago, Loren Pechtel said:

With those numbers how does the reaction chamber avoid melting?

that's what you can read on project rho website:

Zubrin calculates that the 20% enriched uranium tetrabromide will produce a specific impulse of about 7000 seconds (69,000 m/s exhaust velocity), which is comparable to an ion drive. However, the NSWR is not thrust limited like the ion drive. Since the NSWR vents most of the waste heat out the exhaust nozzle, it can theoretically produce jet power ratings in the thousands of megawatts. Also unlike the ion drive, the engine is relatively lightweight, with no massive power plant required.

Zubrin suggests that a layer of pure water be injected into the plenum to form a moving neutron reflector and to protect the plenum walls and exhaust nozzle from the heat. One wonders how much protection this will offer.

Zubrin gives a sample NSWR configuration. It uses as fuel/propellant a 2% (by number) uranium bromide aqueous solution. The uranium is enriched to 20% U235. This implies that B2 = 0.6136 cm-2 (the material buckling, equal to vΣfa)/D) and D = 0.2433 cm (diffusion coefficent).

Radius of the reaction plenum is set to 3.075 centimeters. this implies that A2 = 0.6117 cm-2 and L2 = 0.0019. Since exponential detonation is desired, k2 = 2L2 = 0.0038 cm-2. Then k = U / 2D = 0.026 cm-1 and U = 0.03.

If the velocity of a thermal neutron is 2200 m/s, this implies that the fluid velocity needs to be 66 m/s. This is only about 4.7% the sound speed of room temperature water so it should be easy to spray the fuel into the plenum chamber at this velocity.

The total rate of mass flow through the plenum chamber is about 196 kg/s.

Complete fission of the U235 would yield about 3.4 x 1012 J/kg. Zubrin assumes a yield of 0.1% (0.2% at the center of the propellant column down to zero at the edge), which would not affect the material buckling during the burn. This gives an energy content of 3.4 x 109 J/kg.

Assume a nozzle efficiency of 0.8, and the result is an exhaust velocity of 66,000 m/s or a specific impules of 6,7300 seconds. The total jet power is 427 gigawatts. The thrust is 12.9 meganewtons. The thrust-to-weight ratio will be about 40, which implies an engine mass of about 33 metric tons.

 

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Dear interstellars, I would like to, finally, share another succes story with you.

I wanted to create a space plane that picks up anti matter from a hauler in orbit, and that uses @FreeThinker's excellent fission and fusion tech to go SSTO. The basic principle was easy, copied from @Ciro1983811's SSTO rocket example, but turning that into a working space plane was not. It took me a week experimenting, learning about stability and aerodynamics to go from an awful pilot to a point where I can build a stable space plane and actually land it on the runway.

The turning point was my discovery of the procedural wing, and to a lesser extent, the landing gears from Kerbal foundry. I do not think I could have done it without those.

So I want to show you the result, which I call "the Moth". Here is the Moth's predecessor, which looks way cooler, bit it tended to go into a flat spin on re-entry, in such a way that I could not recover from the spin.Turns out there is more to center of mass than just putting it in front of the center of lift. Boy, I wish KSP would give me more information on the center of drag! Can't wait to try out Ferram once it goes 1.3.

y4mb8D9a3wntSSR0HWNqdgfOg0BkudKHS0qLwPfV

So below here is the Moth. Notice the difference in configuration which puts its center of mass just before the middle of the plane. I would have loved to pull it forward even further, but with all the reactors and the Kerbstein needing to be all the way at the end I could not figure out how to do it. I am open to additional suggestions.

Also I found a wing position that gives a nice balance between stability and maneuverability. If this thing spins out, if I have enough altitude, I can always recover. I am very proud.

It is very tough to find the right way to side-attach things to your vessels body - nacelle-style. I made use of the MKS Honey-badger's side-attachment parts :) 

The Moth takes off on thermal jets with pebble beds, starts out air breathing, moves over to methane (tank is in the middle in the body under the wing, balance is the same with or without fuel) about 16 KM up, when fuel runs out its apo is between 45 and 50 KM. Coast until 40 KM after which the Kerbstein can kick in. It does a 35 degree climb all the way to the top, no need for leveling out, increasing horizontal velocity, none of that stuff. It's wonderful. It used to be able to climb steeper, until I put the wings at a slight angle, which allowed for the final touch I needed - a smooth take-off and more importantly, smooth landing at a low angle of attack.

2 pics of the Moth taking off.

y4mJ5b9B1Wh-NxDIeFu9ySR22Dgug0JAXQjhclfA

y4mhokbeP_bKJq34i148QJKh34kbUuMhk7lIWed3

Switching to Kerbstein above 40 KM.

y4mNqSqdmmxH7AjFEsKuUayrIqQ_RDhWAyBlqREM

Here it is during re-entry, the air breaks are very nice, they also help to provide a soft and slow landing.

y4mxj74YS_IlmvUoxx0IMZ2Y7IuWQNXtSVZmmV69

Finally here is the image showing glorious victory: the Moth handing off 1.5 Kilograms of anti-matter to the Termite! VICTORY!

y4m7XTb12SBco6whVJubjeEQKr8kbAENU1KGpCIy

I hope you enjoyed this report. I had great fun using interstellar technology to create this plane!

Edited by DrScarlett

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Congratulations with making a advanced SSTO and photo-shoot. SSTO building certainly is challenging due to all the balance and aerodynamic effects

Excellent synergy of parts where you made usage if the strength of several KSPI parts. But I wonder if you can go the next step further and land this vessel (with some modifications) on the mun. A possible idea is to make the thermal engine rotate, allowing you to take  off and land horizontally. You might achieve that with infernal robotics. Another idea is to make it warp capable, able reach to otherside of the solar system in a few minutes.

 

 

Edited by FreeThinker

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So I just flew out to Tekto with a ship designed to refuel from atmospheric nitrogen, but to my surprise Tekto's atmosphere is only 5% nitrogen and 80% methane. Considering it is a Titan analog I'd expected it to be more like 98% nitrogen and 1.4% methane. Is this intentional? 

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2 hours ago, FreeThinker said:

Congratulations with making a advanced SSTO and photo-shoot. SSTO building certainly is challenging due to all the balance and aerodynamic effects

Excellent synergy of parts where you made usage if the strength of several KSPI parts. But I wonder if you can go the next step further and land this vessel (with some modifications) on the mun. A possible idea is to make the thermal engine rotate, allowing you to take  off and land horizontally. You might achieve that with infernal robotics. Another idea is to make it warp capable, able reach to otherside of the solar system in a few minutes.

 

 

About the rotating engines, I'm experimenting with that and it's usually not a very good idea. IR joints are very wobbly with KJR too, and if you can make them stable enough, it happens that one engine has a different thrust than the another, with stability issues.

However, with an Atilla and enough energy, you can land vertically without too much hassle, with a good piloting.

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1 minute ago, Nansuchao said:

About the rotating engines, I'm experimenting with that and it's usually not a very good idea. IR joints are very wobbly with KJR too, and if you can make them stable enough, it happens that one engine has a different thrust than the another, with stability issues.

However, with an Atilla and enough energy, you can land vertically without too much hassle, with a good piloting.

Perhaps you should try again, I recently solved some of the balance issues with thermal engines

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1 hour ago, FreeThinker said:

Perhaps you should try again, I recently solved some of the balance issues with thermal engines

Thanks, I will.

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Rotating engines may wobble or may not, but with IR you are able to rotate your ship!  Just add some way of lifting up your nose (for atmosphereless bodies the better your TWR is, the smaller angle you need) and suspension leg to catch your nose from smashing into the ground after landing on the tail and you are good to go.

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3 hours ago, Nansuchao said:

.. it happens that one engine has a different thrust than the another, with stability issues...

Are you using TCA at all?

Thank you, @FreeThinker, for your encouraging words!

 I understand you are trying to up the challenge - I appreciate that. However, disregarding the fact that this thing wasn't purposed for travel to other bodies, if I consider the mun landing proposal, I have to put serious question marks to it.

  • First, along the lines of what @Nansuchao said, it can already transfer to, and land on the Mun. I just land it on its ass on the Kerbstein. See below :) Using rotating VTOLs for that introduces a complication that seems impractical.
  • For using the thermal jets in a rotating fashion I would have to put them near the CoM, or use two pair or them, which would move the CoM way back again, giving me an unbalanced plane. if you want me to make a VTOL based on thermal jets that can rotate the engines, I can try that, but giving it wings as well is weird hybrid mixture.
  • Second, using the thermal jets in a non-atmospheric environment (rotating or otherwise) doesn't make much sense to me. I would have to haul more propellant to the Mun.

I am fine with going for a VTOL concept, but I would not like to design it for both atmospheric gliding as well as non-atmospheric rocketing purposes. it's either - or. I'm sorry, the whole idea just weirds me out. Maybe you should specify the challenge more clearly? How do you want it to take off? How do you want it to land? In atmosphe? In vacuum?

Now adding FTL that is a challenge. i might take you up on that. If you read earlier with my discussion with @Ciro1983811, we already discussed that. 

 

I did a quick adaptation, add some legs and move the tail plane forward, but I nailed it. Barely. Enter the MunMoth :) 

y4mJ1CCyE1VmGW65fPa_6uu7Yec9KuPbgPwqlS6u

Edited by DrScarlett

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13 hours ago, DrScarlett said:

So I want to show you the result, which I call "the Moth". Here is the Moth's predecessor, which looks way cooler, bit it tended to go into a flat spin on re-entry, in such a way that I could not recover from the spin.Turns out there is more to center of mass than just putting it in front of the center of lift. Boy, I wish KSP would give me more information on the center of drag! Can't wait to try out Ferram once it goes 1.3.

 

Have you tried

The Center of Mass, Center of Lift and Center of trust looks something like this in game:

a6Z0Fiu.png

Edited by FreeThinker

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