Raptor9

Raptor's Craft Download Catalog - Concepts & Solutions

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Posted (edited)

7 hours ago, Rune said:

Isn't that like, a huge overkill in liftoff thrust for an underpowered upper stage?

7 hours ago, Rune said:

How thrust-limited are you running that core that it needs to be boosted?

I don't think it's overkill, it's what was needed given the design objective; and the core isn't running thrust limited at all.  The Twin Boar boosters have fuel lines feeding the Mammoth, so the boosters go through their fuel more quickly, but the core stage is still full at booster jettison.  The entire core stage/booster set provide almost all of the total velocity needed to achieve LKO.  With a payload above 45 tons, the NITE's Poodle doesn't have the TWR to circularize the orbit quickly enough before falling back into the atmosphere.  I originally intended to make two variants based on my 4C and 4C+, but having two Kickbacks just wasn't enough thrust and delta-V to achieve orbital velocity.  Yes, I could add MOAR boosters like in your screenshots, but I prefer to keep the lineage of the 'Titan' family with just two (my personal flavor :P).  I'll explain why I used the "under-powered" Poodle below.

7 hours ago, Rune said:

What is under the fairing is pretty much a clone of your NITE upper stage, if I can clone going by a picture (there is a tank inside the 3.5-2.5m adaptor, right? a shame not to use the empty space), with just a different RCS/docking port arrangement (I'm a big fan of 'universal 1.25-2.5m ports'). The first one gets 45mT to LKO+1km/s (pretty much your standard trans-Duna injection), and the second one, a whooping 85mT to LKO+650m/s (45mT to LKO+2km/s with the 40.5mT heavier notNITE, i.e a carbon copy of yours).

Those designs of yours would work for sending payloads to their destinations, but they won't have the delta-V to return to Kerbin for reuse.  This is where the 'Poodle' and the large fuel reserves of the NITE come into play.  Granted, they'll need to be refueled at their destinations, which is why the initial handful of NITE's should establish an ISRU site.  But the NITE's need the dV reserves to propel themselves back to Kerbin and propulsively capture back into LKO.  Neither of your upper stages have the capability to do that just by estimating off your KER windows (not even from Duna).  I don't want to get into a dV/TWR/engine selection debate, but IMO the Poodle provides a decent balance of TWR vs delta-V when compared to an NTR-powered stage, not to mention it weighs a lot less than just one NTR.  Plus using an LF+O mix reinforces the resource logistics of propulsion, control, and back-up power generation.  I also compared using the Rhino, which would give a much greater TWR obviously, but the mass of the engine itself slashed the dV significantly, despite having almost the same ISP as the Poodle.

So far, the worst case I've tested is launching a NITE to low Eve orbit with a constellation of 8 satellites, and repositioning itself to Gilly orbit to await refueling from an ISRU site.  That scenario requires a lot of dV.  Again, smaller fuel-capacity upper stages wouldn't work, and the NITE's Poodle performed just fine.  The bottom line: the NITE is designed to perform multiple functions across multiple destinations, on an interplanetary-scale of reusability, and this setup provides a good design to fit that objective.  Is it the best design?  Probably not; but with the amount of testing and comparison I performed, it's a solid choice.

7 hours ago, Jester Darrak said:

But what I'm missing overall is the option to bring the more expensive boosters and first stages back to Kerbin. I'd rather lose 5-10 tons of payload and bring those Twin-Boar and Mammoth equipped stages back to the surface

Nothing is stopping any users from modifying the designs to do just that, or take advantage of the Stage Recovery mod.  Launching, launching, launching can get repetitive for me during a full career, and the last thing I want to do is add recovering stages to the surface.  Most of the heavy payloads I launch that require the lifting power of the 4C or 4C+ end up being expensive but reusable craft anyway, like the EV-4 'Longship' family, so such large costs don't occur often, and saving a pair of Twin Boar boosters or Rhino upper stages don't provide a dent in the overall costs of those expensive launches to be worth my trouble.

While I would enjoy a mechanic in stock KSP that makes use of a SpaceX booster fly-back or ULA S.M.A.R.T. engine reuse, incorporating this into my KSP save just adds a lot more grind-time into a single launch that I would rather spend elsewhere.  But that's just my personal preference talking.  I prefer to focus on in-orbit refuel/reuse/propellant generation concepts like ULA's "CisMunar 1000".

Edited by Raptor9
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A low-thrust upper stage can be a perfectly good option if the engine is much more efficient. For my Constellation-style missions that I've been doing lately, I've been using an Ares V mimic which has a 70 tonne maximum payload to LKO and only a 600kN engine with a 400s Isp on the upper stage. The efficiency-over-thrust approach works well because the vehicle is often used for transporting payloads far below its maximum capacity and the upper stage is then repurposed as a transfer stage. Alternatively, when it's being used with more massive payloads (such as 70-ish tonne chemical propulsion modules), the high thrust-to-weight of the first stage helps to achieve a long time to apoapsis, which gives the second stage time to reach the final apoapsis and circularize.

I think it's an effective method because of the main idea behind the Constellation program's launch vehicles: only two launchers were used to minimize manufacturing costs, and the Ares V in particular was supposed to be very versatile to allow a wide range of mission profiles despite the limited launch vehicle options. The versatility of the Ares V is a good comparison for the NITE upper stage, which is designed to be incredibly versatile and presumably is mostly intended for use in space, where high thrust is less relevant. Because of that, the Poodle engine is a good choice as it has the highest Isp of any chemical rocket engine and a relatively low mass too (compared to the size of the stage).

PddV7Ss.jpg

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Posted (edited)

3 hours ago, Raptor9 said:

I don't think it's overkill, it's what was needed given the design objective; and the core isn't running thrust limited at all.  The Twin Boar boosters have fuel lines feeding the Mammoth, so the boosters go through their fuel more quickly, but the core stage is still full at booster jettison.  The entire core stage/booster set provide almost all of the total velocity needed to achieve LKO.  With a payload above 45 tons, the NITE's Poodle doesn't have the TWR to circularize the orbit quickly enough before falling back into the atmosphere.  I originally intended to make two variants based on my 4C and 4C+, but having two Kickbacks just wasn't enough thrust and delta-V to achieve orbital velocity.  Yes, I could add MOAR boosters like in your screenshots, but I prefer to keep the lineage of the 'Titan' family with just two (my personal flavor :P).  I'll explain why I used the "under-powered" Poodle below.

Those designs of yours would work for sending payloads to their destinations, but they won't have the delta-V to return to Kerbin for reuse.  This is where the 'Poodle' and the large fuel reserves of the NITE come into play.  Granted, they'll need to be refueled at their destinations, which is why the initial handful of NITE's should establish an ISRU site.  But the NITE's need the dV reserves to propel themselves back to Kerbin and propulsively capture back into LKO.  Neither of your upper stages have the capability to do that just by estimating off your KER windows (not even from Duna).  I don't want to get into a dV/TWR/engine selection debate, but IMO the Poodle provides a decent balance of TWR vs delta-V when compared to an NTR-powered stage, not to mention it weighs a lot less than just one NTR.  Plus using an LF+O mix reinforces the resource logistics of propulsion, control, and back-up power generation.  I also compared using the Rhino, which would give a much greater TWR obviously, but the mass of the engine itself slashed the dV significantly, despite having almost the same ISP as the Poodle.

So far, the worst case I've tested is launching a NITE to low Eve orbit with a constellation of 8 satellites, and repositioning itself to Gilly orbit to await refueling from an ISRU site.  That scenario requires a lot of dV.  Again, smaller fuel-capacity upper stages wouldn't work, and the NITE's Poodle performed just fine.  The bottom line: the NITE is designed to perform multiple functions across multiple destinations, on an interplanetary-scale of reusability, and this setup provides a good design to fit that objective.  Is it the best design?  Probably not; but with the amount of testing and comparison I performed, it's a solid choice.

Riiiight, the reuse, I must confess I totally forgot about that. And fuel lines, I have kind of totally forgot that those ever existed, lately. :blush:

I still think a taller core coupled with SRB's like in the second picture I showed (where I was copying liftoff thrust and seeing where it went), would be cheaper, and you should see the awesome SRB spread when they stage, but now everything you did makes much more sense. I would correct you on one point, tough: on that big one in the second pic, there is pretty much the same performance as yours, if you add a S3-7200 to the upper stage instead of 40,5mT of the 85mT payload. Now, I haven't taken it to Duna and back to work it out, but the upper stage spends something like 200m/s or less circularizing in LKO, so I'd say pretty confidently that it should have just as much juice left as yours.

So maybe at least now you know you could go back to SRBs, if you so desire? Plus, you have a good idea of what it'll take to lift the NITE on its own (the first booster has a payload that is almost the same weight as the s3-7200 tank my smaller upper stage lacks). Aesthetic choices, of course, are a very personal thing, but there are rocket out there with six or more boosters (Delta II, PSLV, off the top of my head).

 

Rune. And I had lots of fun reverse-engineering yesterday. Hope you don't mind! :)

Edited by Rune
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Nah, I don't mind at all, I did like the first rocket picture with the Twin Boar surrounded by six Kickbacks, and the larger tank on top.  Reminded me of the Ares I rocket.

3 hours ago, Rune said:

Now, I haven't taken it to Duna and back to work it out, but the upper stage spends something like 200m/s or less circularizing in LKO, so I'd say pretty confidently that it should have just as much juice left as yours.

Unless your maneuver-plotting skills are leaps and bounds better than mine (which is probably true anyway), I usually require a lot of delta-V to propulsively capture back into LKO after an interplanetary transfer.  Then again, your upper stage wouldn't have any payload, and it's probably way lighter in mass than mine....hmmm.  Something to run some numbers against when I get some time to kill.

3 hours ago, Rune said:

I still think a taller core coupled with SRB's like in the second picture I showed (where I was copying liftoff thrust and seeing where it went), would be cheaper,

That second rocket you were referring to, the core 1st stage and six SRB's are only 12,000 funds cheaper than the core stage & Twin Boar boosters of the 'Titan 4N'.  That's not really that much considering the total cost of sending interplanetary payloads IMO; but like you said, to each his own.

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Posted (edited)

56 minutes ago, Raptor9 said:

Unless your maneuver-plotting skills are leaps and bounds better than mine (which is probably true anyway), I usually require a lot of delta-V to propulsively capture back into LKO after an interplanetary transfer.  Then again, your upper stage wouldn't have any payload, and it's probably way lighter in mass than mine....hmmm.  Something to run some numbers against when I get some time to kill.

Errr I meant with the same fuel load on the upper stage! As it is on the pics, it's 85mT of payload. With an additional bigger tank like yours (a 40.5mT wet S3-7200), payload would be 45mT, and the dV would be the same as a Titan 4N. Meaning, the second rocket has the same performance as yours, which was kind of my point.

56 minutes ago, Raptor9 said:

That second rocket you were referring to, the core 1st stage and six SRB's are only 12,000 funds cheaper than the core stage & Twin Boar boosters of the 'Titan 4N'.  That's not really that much considering the total cost of sending interplanetary payloads IMO; but like you said, to each his own.

Yeah, you would think using half the high-performance engines would save you more than that, but then KSP goes and makes tankage relatively expensive in comparison... and the twin boar costs less than a single Vector and includes tankage, that's also a thing. It would be a really good candidate for core stage recovery, though, all the cost is in the almost-orbital core. And, you know, that SRB plume looks gorgeous to me.

BTW, speaking of nice-looking rockets, the family I was inspired to build would be complete with this one:

MeAz7Fz.png

If you just grab the core + Boosters on each, these three make a fine booster family indeed, with ~25mT (2xSkipper, 2xKickback), ~50mT (1xTwin-Boar, 4xKickback), and ~100mT to LKO (1xMammoth, 6xKickback), and a very similar thrust curve (Ok, the second was a bit sportier, but everything is solved if you take out two kickbacks). And then the upper stage would be the customer's business, and I can avoid publishing anything similar to your stuff. :) I'm still debating whether to include control and/or recovery stuff, as it is they make very nice 19-26 part subassemblies.

 

Rune. It shows I was just halving core thrust on each iteration. Yay science!

Edited by Rune
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Posted (edited)

1 hour ago, Rune said:

I'm still debating whether to include control and/or recovery stuff, as it is they make very nice 19-26 part subassemblies.

Well, if you left attitude control to the customer's payload, that would save a lot of funds since a single Vernor thruster isn't cheap (:funds:1,400).  I justify their use on my LITE and NITE stages since they're intended to be reused and end up paying for themselves, but I'm in the process of designing a different upper stage for my 'Thunder 3' for this very reason.  Monopropellant-based RCS systems on an upper stage can add part count and an additional resource, but they're much cheaper.  Of course, if you're planning on recovering the upper stage on Kerbin, the argument is moot as well. :)

Edited by Raptor9

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Posted (edited)

Want to pick your brains, Raptor9: If you need to carry Mk3 cockpit, 2 Mk3 cabin, a lab, and an ISRU-Drill combo to Duna surface AND back, would you go with NITE with extra fuel tanks and more poodles (0.33 inital TWR, but at around high 4k dv), or would you just go with rhino (Inital TWR of around 0.75, but dv of around 4k)?

EDIT: used hyperedit to find out NITE can barely depart from Duna in a timely manner.

Edited by Jestersage

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That depends on how much efficiency you want to squeeze out.  Personally, I prefer to use a low-thrust engine with higher Isp to get more delta-V in the long-run; even if that means I have to do several burns at periapsis prior to the final escape trajectory burn.  So to answer your question, I would use just a single NITE with additional tankage.  Without summoning the wrath of other players that disagree, TWR doesn't mean much to me unless you get below 0.10-ish.  If it's above 0.25, I'm satisfied.  Using a 9-ton Rhino engine to achieve a TWR of 0.75 during a trans-Duna injection burn in vacuum is a waste IMO.

The NITE wasn't designed to take payloads to a planetary surface, so I can't speak for how the design will work out.

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Posted (edited)

56 minutes ago, Raptor9 said:

The NITE wasn't designed to take payloads to a planetary surface, so I can't speak for how the design will work out.

Stick landing legs on it and it should be good for most places (other than Tylo, Eve, Laythe, and Kerbin). The Poodle can lift about 75 tonnes from the surface of Duna, which should account for most conventional payloads. Leaving a tank in orbit of Duna for the modified landing-capable NITE stage to dock with (and then redock to the payload) would probably make it a very good transport system for most payloads from Kerbin orbit to the surface of Duna and back, and it would just require refueling of the extra tank as well as the tanks on the NITE. I'd personally prefer a dedicated lander design, but there's no real reason why repurposing the NITE wouldn't work. Drag may be a concern, but Duna's atmosphere means that it'll barely make a difference.

Edited by eloquentJane
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2 minutes ago, eloquentJane said:

Stick landing legs on it and it should be good for most places (other than Tylo, Eve, Laythe, and Kerbin). The Poodle can lift about 75 tonnes from the surface of Duna, which should account for most conventional payloads. Leaving a tank in orbit of Duna for the modified landing-capable NITE stage to dock with (and then redock to the payload) would probably make it a very good transport system for most payloads from Kerbin orbit to the surface of Duna and back, and it would just require refueling of the extra tank as well as the tanks on the NITE. I'd personally prefer a dedicated lander design, but there's no real reason why repurposing the NITE wouldn't work. Drag may be a concern, but Duna's atmosphere means that it'll barely make a difference.

That's what I did with the LITEs and Titan 2Ps. Screw some legs on it and use them to haul fuel from Mün and Minmus surface to in-orbit fuel depots.* As much as I like the concept of the 'Purpoise', LITE and T2P seem more efficient to me, could be subjective though, didn't do the math.

 

*requires KAS/KIS + engineer at the mining outpost

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33 minutes ago, Jester Darrak said:

That's what I did with the LITEs and Titan 2Ps. Screw some legs on it and use them to haul fuel from Mün and Minmus surface to in-orbit fuel depots.* As much as I like the concept of the 'Purpoise', LITE and T2P seem more efficient to me, could be subjective though, didn't do the math.

Well, the purpose of the 'Porpoise' (see what I did there? :sticktongue:) was to provide better surface access to it's payload since it's a horizontal lander.  Regarding the B-model 'Porpoise' specifically, as a propellant transport it has the advantage of being able to "taxi" to the side of the mining rig to plug in directly.  Otherwise, you would need to have the miner on wheels to drive to the propellant lander, or have a "fuel truck" rover shuttle between the two (which can get tedious).

A LITE with landing legs and an additional fuel tank docked on top would be more efficient (and less expensive) in that role since there would be less hardware mass riding along (the HLV-5's array of small landing thrusters and additional Vernors for instance), but again it would require a different approach to propellant loading on the surface.  So a little bit of column A, a little bit of column B. :)

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Posted (edited)

Hey Raptor, I just had an idea for a new long to long,long term goal for ya. The (real-life) X-15 seems like a cool idea for an early sub orbital space-plane.

I've built an X-15 replica of my own, and I think it might be interesting to see you have a go at it.screenshot243.png

Just an idea.

Edited by Frednoeyes
Added an image
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6 hours ago, Frednoeyes said:

Hey Raptor, I just had an idea for a new long to long,long term goal for ya. The (real-life) X-15 seems like a cool idea for an early sub orbital space-plane.

I've built an X-15 replica of my own, and I think it might be interesting to see you have a go at it.

I've dabbled in that area from time to time, a pure rocket suborbital spaceplane, but I never really found much use or fun out of it.  I even tried doing the mothership-drop method, but again, never got it to my liking.  I'm pretty picky when it comes to what I publish.

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10 hours ago, Raptor9 said:

I've dabbled in that area from time to time, a pure rocket suborbital spaceplane, but I never really found much use or fun out of it.  I even tried doing the mothership-drop method, but again, never got it to my liking.  I'm pretty picky when it comes to what I publish.

Fair enough, I like build my replicas to be a bit more accurate(useless) than yours anyways, and I only barely got the mothership method working.

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Absolutely love your stuff Raptor9. Your designs actually helped get me hooked on the game again after about a year. One quick question... Is there anywhere I can download all your .craft files at once instead of one by one? That would be a huge help. I'm a business traveler and I play Kerbal in my downtime. I'm just trying to prep my laptop for the next trip.

 

Thank you for being awesome!

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Hi @Hajii, welcome to the forums. :)

I understand what you mean regarding business travel.  I myself am currently messing around with KSP on a laptop while on a business trip.  Unfortunately, there isn't a way at the moment to download all my craft at once.

However, you're not the first person to ask for this, and I've been looking at ways to set up a series of mass downloads.  Namely, how do I have a setup that makes the process easy to download, but also efficient enough for me to quickly update the links whenever I update any craft files, which happens on occasion especially after KSP updates.  So I am working on it.

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@Hajii i bealive somone created a mostly correct zip file of raptors craft it may be a few pages back in this forum thread 

-JWOC

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@JWOC Thanks - It was a bit dated so I just went ahead and downloaded them all myself. I also included separate folders for all the infographs. The download is here. I probably missed something as it was quite a lot but hopefully the majority are there.

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The Kerbin Orbiting Satellites are a little hard to launch without RCS...

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21 hours ago, redmonddkgamer said:

The Kerbin Orbiting Satellites are a little hard to launch without RCS...

Judging by the looks of the launch vehicles they should fly pretty much perfectly. Are you sure you're flying them correctly? If you're starting the gravity turn closer to 20km altitude than 2km, that's what the problem is.

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I should also note that I always launch all my rockets keeping the G-meter no higher than 2 G's.  Anything above 2 and I'll continuously throttle down to keep the acceleration under control.  If you keep the throttles maxed on these rockets you'll probably be encountering drag losses along with a difficult gravity turn.

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On 18/03/2017 at 10:45 AM, eloquentJane said:

Judging by the looks of the launch vehicles they should fly pretty much perfectly. Are you sure you're flying them correctly? If you're starting the gravity turn closer to 20km altitude than 2km, that's what the problem is.

I honestly don't know. I just stuck some thrusters and one of the radial RCS tanks under it and boom.

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 Those landers... I have no words. Great work, Raptor! :) 

Fire

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love your craft they are the best, have used them many a time

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