200 Tons to Oribit

[thepackett]

I've been trying to get a 200 ton payload into orbit around kerbin, but the ship simply falls apart during launch, and not due to (intuitive) design flaws either. Every launch a random part simply falls off, even though the rocket is flying completely stable with no oscillations. The odd part is that I've succeeded in getting it into orbit before with almost the exact same design I've been using.

Payload:

Launcher Design:

Screenshot from Successful Launch:

My question is, how do you build a launcher this large without it simply falling apart due to the game's physics? Are there certain parts to use, game quirks to watch out for, or ways to pilot the rocket in flight so that it does not fall apart as if it was made of cheese?

[Collin Cutler]

Thats a lof of Skippers..... any who, Put the clamps on the center fuel tank insted of the outer ones. This will not have the center droop down when the rest of the rocket is connected to the clamps.

[mhoram]

My question is, how do you build a launcher this large without it simply falling apart due to the game's physics? Are there certain parts to use, game quirks to watch out for, or ways to pilot the rocket in flight so that it does not fall apart as if it was made of cheese?

In my expeience while designing my Tangent Lifter family, it was mostly trial and error.

Sufficient strutting, but not overdoing it is necessary. If it is Asparagus-Style keep the shear-forces small.

You might find some inspiration here:

http://forum.kerbalspaceprogram.com/threads/51828-What-s-the-highest-mass-you-ve-ever-put-into-Kerbin-orbit-with-a-single-ship

Or if you plan to make it most efficient: http://forum.kerbalspaceprogram.com/threads/55615-Payload-Fraction-Challenge

For really heavy payloads,

gives some nice hints (thrust plates!).

And by the way, you don't see rockets that can lift 200 ton payloads into orbit every day.

[Taki117]

Looks like your outer most ring could use more struts, instead of just strutting top and bottom in a straight line, try strutting top, bottom, and middle in a straight line, then make an 'X' with struts from top to middl and bottom to middle and see if that helps.

[blizzy78]

Looks like your outer most ring could use more struts, instead of just strutting top and bottom in a straight line, try strutting top, bottom, and middle in a straight line, then make an 'X' with struts from top to middl and bottom to middle and see if that helps.

This. It cannot be stressed enough that triangles are an engineer's best friends.

[thepackett]

Thanks for all of the helpful advice, I'll post back here again once I get a working design!

[DerekL1963]

My question is, how do you build a launcher this large without it simply falling apart due to the game's physics?

In no particular order. Use fewer, but longer burning and higher thrust asparagus stages. Thrust plates are good for some situations, but mostly they are just duct tape that increases your lag and parts count because you have a bad design. Download and install MechJeb or Kerbal Engineer Redux so you have solid numbers on what each stage is doing. Consider installing Kerbal Joint Reinforcement. Build smaller boosters first and then work your way up as you learn how to build. Learn how to minimize your parts count for the task at hand. (More parts = more joints = more things that can slip, slide, or bend.) Search out Temstar's Zenith series boosters, read the thread for some of the theory of big booster design, then download them and take them apart and study them closely.

Here's my booster (just about ready for public release) that boosts a five tank payload to 150km - note the complete lack of thrust plates or insane amounts of struts. It's completely stock except for Kerbal Joint Reinforcement. The non KJR version (in work) needs more struts, but still doesn't need thrust plates.

And build rockets, and watch them fly, figure out how to fix any problems, lather, rinse, repeat. There's simply no substitute for hard performance numbers and experience.

[Genolution]

Two words. "Thrust Plate". Your boosters are probably shearing off as forces are pushing down on the center stacks and lifting up on the outer stacks as they gain better thrust to weight ratio as they burn fuel. To combat this I employ thrust plate technology with I beams and panels that sits on top of my boosters and under the payload. In this pic I put up 7 full orange tanks and the orange tank on my last booster still had all it's fuel left for a total of 307 tons into a 100km orbit. Not only do they provide a stable platform to spread out the thrust but its very easy to secure your payload on top of the plate with struts and girders.

[breakthrough]

http://forum.kerbalspaceprogram.com/threads/57787-Jaekelopterus-Heavy-Lifter

Only super-heavy lifter I've come across with a tolerable part count. Dissect it to learn Corona688's secrets or just use it yourself.

[Iansoreta]

This. It cannot be stressed enough that triangles are an engineer's best friends.

YES DUDE YES, That's what i'm doing everytime I design VERY heavy launcher that can launch more than 100 ton payload, and it needs a lot of triangular designs without adding KSP mods that makes some sort of triangular beams, and I don't want mods in my game in order to keep it clean and mod free. I also know thrust plate concept, and the strengths of the triangular design(it cannot be deformed easily when used the triangles correctly). I'm using current version of KSP(version 0.23.5) and I'm still continuing the legacy of other KSP players by doing what is best for my spaceship design especially my computer.

[Red Iron Crown]

SLS parts make it a bit easier, I got a 207t payload into orbit with a 1200t lifter and about 80 parts.

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[michaelhester07]

I don't remember if this has any mods in it but I'll share it anyway. You can use my Ultima 7 lift motor. It's mostly stock but might have some parts from Near Future Tech structural.

Ultima 7 UHL Lift motor

I regularly lift 500 ton spacestations with these.

Copy the craft file into your save's subassemblies folder.

[SRV Ron]

As others have mentioned, proper bracing, triangles, are the key to large payloads. Onion staging seems to work best on such large payloads by allowing stronger bracing not possible using asparagus staging. Keep the design as simple as possible and look for that efficient thrust to weight ration for best payload ratio. Example below;

And the payload in orbit.