Good launch vehicles?

[scotty93]

So, i'm not very good at making launch vehicles for medium-heavy or heavy payloads. What kind of designs do you guys use? Do you have any tips or examples that I could maybe use?

[Giggleplex777]

I just perfected this 40 ton lifter today. It uses advanced engine staging (in which engines are jettisoned as the rocket gets lighter) and crossfeed between the boosters. It also has a deorbit motor for the core booster once it drops of the payload.

Has a payload fraction of 16.19%!

Edited April 23, 2013 by Giggleplex777

[Temstar]

The secret is asparagus staging - without it your launch vehicle will quickly balloon to unwieldy size. Aside from that I'm an advocate of clustering 1.25m engines, particular in conjunction with asparagus staging and particularly for the core stage of an asparagus staging rocket where its high Isp really becomes important given the very long burn time of a core stage.

Putting the above into practice I built the Zenith rocket family:

[Spatzimaus]

It depends on what you're trying to do. It's not too hard to make what we call "asparagus" staging, where a series of boosters are radially attached to a central core, and the outer layers (which also feed fuel to the inner layers) are ejected as they run out of fuel. It's basically the solid rocket boosters of the shuttle/energiya system taken to the extreme, although you generally use liquid-fuel engines for it. It's a bit harder to make a rocket that doesn't shed parts as it goes up, although it can be done. (A single-stage design just won't be as efficient.) Once you get the basics down, it's not hard to tune any booster design to have increased payload and/or a better range. The way rockets work, you can always go bigger (i.e., MOAR BOOSTERS) if you want to launch a bigger payload, because there's no real limit other than part count.

Take my "Bucket" design, a 4000-ton rocket capable of placing a 500-ton payload into a circular low Kerbin orbit, or getting that object almost out of Kerbin's gravity well entirely (and therefore most of the way to, say, Jool):

It requires the KW Rocketry mod, since those rocket stacks are 3.75m tanks. But it's a single-stage design, not shedding any parts as it goes up, and can be safely de-orbited to prevent any possible debris collisions.

So if you need a good launch vehicle, it's not too difficult. Just make something that has a thrust-to-weight ratio of about 2.2ish, and a delta-V of at least 4000 m/s, and you can get to orbit. If you find yourself continually coming up a bit short, just add another stage or slap on a couple more SRBs.

[scotty93]

You all have very nice looking launch vehicles, good work.

I have a concept in my head for a cruiser that I am going to build, so I'm looking for an example of something that can take it to at least a 100,000M orbit. I could refuel it after that. I don't know what the weight would be, but it will have around 4 NERVA's, less than 8 of the FL-T800 Fuel Tanks, secondary systems and armor plating. It probably wouldn't be a problem for any of you, but it would be one of the largest things I've launched since 0.15.

[M5000]

You all have very nice looking launch vehicles, good work.

I have a concept in my head for a cruiser that I am going to build, so I'm looking for an example of something that can take it to at least a 100,000M orbit. I could refuel it after that. I don't know what the weight would be, but it will have around 4 NERVA's, less than 8 of the FL-T800 Fuel Tanks, secondary systems and armor plating. It probably wouldn't be a problem for any of you, but it would be one of the largest things I've launched since 0.15.

You mean something like this?

That is an SSTO similar to Spatzimaus's design. It's the fuel/engines for a cruiser I've yet to complete. Gets to orbit entirely empty except for the RCS tanks. Again, SSTO, but it will need to be refueled later.. Those orange tanks are NOT the stock ones, by the way. Those are the KW rocketry 3.75 meter ones. There's a stock orange tank on there, but it's kinda hidden. Absolutely dwarfed by those massive KW tanks.

Here it is in the hangar, though I think with those tanks filled (the orange ones) and the ascent boosters (the white ones) detached, the actual delta-V was something like 12Km/s... Also, that top nose cone on the propulsion module detaches when you get rid of the main boosters. It's just a support cone with an ASAS module, some batteries and some RTGs and a decoupler. Below it is a CBM docking port to go to the core of what will be the ship, then the command module.

But yeah it all depends on what you want to lift. Could I have lifted that payload to orbit with all the fuel intact? Sure. Would it have been a LOT more boosters and such? Hell yeah. Build a lifter for general purposes (Usually something like Temstar's stuff up there will work for whatever payload you want to do) and just use it for all the missions you can fit onto it.

Edited April 23, 2013 by M5000

[AmpsterMan]

I just perfected this 40 ton lifter today. It uses advanced engine staging (in which engines are jettisoned as the rocket gets lighter) and crossfeed between the boosters. It also has a deorbit motor for the core booster once it drops of the payload.

-snip-

Has a payload fraction of 16.19%!

That is a pretty launcher Giggle. I like

[Simplicity]

While it not as fancy as the ones above here is mine, not sure of its lifting capabilities as I never really looked into it

[Flixxbeatz]

Here's mine. My workhorse for medium - near heavy payloads (resuppy vehicle launch). 25 engines at first stage (5 each core, 22x LV-T30, 3x LV-T45), asparagus config. second stage depends on the payload.

and it looks like a real rocket.

This one is for much heavier payloads, with larger first stage (stretched + more engines) but works identically the same as the one above. 4 strap-on asparagus, 7 engines each (6x LV-T30 and 1x LV-T45, and 7x LV-T30, 35 engines on the first stage). second stage depends on the payload.

and still it looks like a real rocket.

[Brotoro]

I'd show you some of mine, but they occasionally do weird things that I don't understand, like begin to spin near staging, or be strangely uncontrollable during the start of gravity turn, all for no discernible reason. And I say "for no discernible reason" because I can't get the weirdness to repeat reliably. On many flights the behavior is minor or nonexistent...and on other flights the exact same rocket will deviate into weirdness. It makes my brain hurt.

[NeoMorph]

I use a modified Arianne booster that replaces the SRB's with liquid fuel stages. Most of my interplanetary stuff is assembled in orbit so I don't have problems having to launch anything bigger. Only rocket that is larger is my four orange tanks booster that I use as a fuel depot in orbit.

[Brofessional]

This puts about 130 tons into orbit. The part count is a bit high and it can be a little tricky to pilot though.

[Tw1]

I've found the tricks to a good launch vehicle are keep it bigger at the bottom and be a stickler for symmetry and evenness. Reinforce everything with struts.

A good side effect of using the heavy mainsail engines is they keep weigh nearer to the bottom. Longer tanks on lower stages might also help with that.

I like to radially attach SAS units to central tanks, it helps to have control in case the rocket tips the wrong way.

I tend to only use separatrons on side mounted tanks, angling them perpendicular to make sure the booster clears the other engines. My rule of thumb is they go half way between the radial decoupler and the engine.

Lately, I've been building launch vehicles with the boosters arranged in a square formation, (radial decouplers at 90 degrees from each other) but simple circular arrangements have served me well previously.

I once managed to launch a 100 ton payload. Each booster consisted of a jumbo tank, and a mainsail.

The top had seven boosters, six radially placed around a centre one. This was asparagus staged. Below that were seven more boosters, with pipes to ensure fuel levels in each tank stayed equal.

Around that were twelve more boosters, with fuel draining from their tanks to the ones in the centre.

It needed so many struts, lagged a fair bit and was hard to control, but it got there. Just.

It didn't help that the payload was asymmetrical, and required the whole rocket to be spun as it went up. And that the command pod was upside down.

That payload had to burn its engines for a long time, and even reentered the atmosphere before it achieved orbit. But it made it, and then went to Duna, where it is waiting to carry my Kerbalnaughts home.

But I'm never doing that again.

Edited April 23, 2013 by Tw1

[chainedlupine]

I do most of my lifting in the 40-60 ton range. Generally, a rocket that can handle more than just stresses out my PC too much.

My turn-key design ends up a lot like a scaled down version of Temstar's SHLLV's design. Sometimes I use a clustered central stage, other times I use just a single mainsail -- just depends on what I need to actually get the thing into orbit. (KSPX's mini-mainsail plus a few clustered LV-30Ts are perfect most of the time.)

This guy was my heavy Duna lander, IIRC around 40-ish tons payload:

Rockets like this are pushing the limits of my system. Any more parts, and it becomes a slide show.

[Accelerando]

I use a two stage configuration, two outboard boosters, fuel crossfeeding to the inner tank, cluster engines or a mainsail in the center, mainsails on the outside, fins for aerodynamics, sepratrons for staging. The stacks should be 1 orange tank high for ~20 tons, 1.5 for ~30 tons, 2 for ~40 tons. I don't care about launching anything heavier than 60 tons. Part counts are too high and engineering isn't worth it for me anymore.

[magnemoe]

An very simple design is the orange tank on top of an small gray with an mainsail below, use 2-4 struts to connect the gray tank with the orange.

use 4 or 6 booster with orange+ large gray tank in asparagus.

Now if I want to launch an huge interplanetary ship I either use the nuclear engines on it as the center of the asparagus or add dropable engines on it.

Far easier to refuel than to build in orbit.

[Mortaz]

Hello fellow Kerbalnaut, i am new at this so bare with me. I would like to say that after a year of playing this game, i have finally created a reliable family of launch vehicles. The only problem as i can see from other peoples design is mine are not fully embracing the Aspargus staging method or high Isp like Temstar, however i have good faith in my rockets and are sure to be able to perform reliably...( the large rockets do get a bit wobbly but it's fine...i think).

once i have time to create a well laid out table on the spec's and capabilities of my rockets, then i will post them on here.

The Thor rocket family can lift payloads from 1 tonne - 75 tonnes into 100km orbit (in development; creating a launcher to lift 150 tonnes!!! keeps falling apart though).

Lastly i use only stock parts, the only mod i use is the engineer mod to help get the info i need to make my rockets.

[Mortaz]

Hello fellow Kerbalnaut, i am new at this so bare with me. I would like to say that after a year of playing this game, i have finally created a reliable family of launch vehicles. The only problem as i can see from other peoples design is mine are not fully embracing the Aspargus staging method or high Isp like Temstar, however i have good faith in my rockets and are sure to be able to perform reliably...( the large rockets do get a bit wobbly but it's fine...i think).

once i have time to create a well laid out table on the spec's and capabilities of my rockets, then i will post them on here.

The Thor rocket family can lift payloads from 1 tonne - 75 tonnes into 100km orbit (in development; creating a launcher to lift 150 tonnes!!! keeps falling apart though).

Lastly i use only stock parts, the only mod i use is the engineer mod to help get the info i need to make my rockets.

[Wayfare]

The secret is asparagus staging - without it your launch vehicle will quickly balloon to unwieldy size. Aside from that I'm an advocate of clustering 1.25m engines, particular in conjunction with asparagus staging and particularly for the core stage of an asparagus staging rocket where its high Isp really becomes important given the very long burn time of a core stage.

While I appreciate the craftsmanship in your launchers - and cracking the fuel line/strut problems in Subassembly Manager was a real stroke of genius - I disagree with your assessment of asparagus staging and engine clusters. The Munshine launcher family uses inline staging and one-piece engines to achieve similar payload capacities and payload fractions (around 13% I believe) but with a lot less parts:

They were built on the assumption that parts count is the major bottleneck in KSP designs right now, though they have exceeded our expectations in terms of fuel and mass efficiency.

...and yes, we need to re-release them with a sensible numbering convention. Right now they're numbered by the order in which they were designed, which is confusing

Edited September 26, 2013 by Wayfare

[fatfluffycat]

The Kivceter SLV, It can lift 20 tons(thats good for me because I do mostly probes and rovers)

Edited September 26, 2013 by fatfluffycat

[Epthelyn]

My recently created 'go anywhere' probe is light enough to be lifted by a central orange tank + mainsail after 4 radially attached orange tanks + 4 mainsails. The 4 engines first first, then the inner engine fires after staging. It can be easily adapted to fire all 5 engines at once though.

That works for most of the things I launch, provided in some circumstances that the payload has its own method of propulsion.

[AmpsterMan]

Don't know if this is appropriate, but recently I have had a paradigm shift of efficient Launchers with high payload fractions, asparagus boosters, and two main serial stages, with somewhat inneficient, lower payload fraction, serially 3-staged rockets. My reasoning is that they usually require fewer parts, easier to assemble, and just look s bit more beleivable to me. I'll share if anyone is interested.

[Giggleplex777]

Don't know if this is appropriate, but recently I have had a paradigm shift of efficient Launchers with high payload fractions, asparagus boosters, and two main serial stages, with somewhat inneficient, lower payload fraction, serially 3-staged rockets. My reasoning is that they usually require fewer parts, easier to assemble, and just look s bit more beleivable to me. I'll share if anyone is interested.

I would like to see them.

[Mortaz]

Don't know if this is appropriate, but recently I have had a paradigm shift of efficient Launchers with high payload fractions, asparagus boosters, and two main serial stages, with somewhat inneficient, lower payload fraction, serially 3-staged rockets. My reasoning is that they usually require fewer parts, easier to assemble, and just look s bit more beleivable to me. I'll share if anyone is interested.

I am keen to see the hard work that you have put into creating your rockets

[Brotoro]

I await seeing the fruits of AmpsterMan's labors.