How to build a heavy lifter that doesn't collapse?

[Cartz]

My solution? Break it up into packages of a mass you can manage, then assemble it on orbit. You know, the way von Braun said to, and the way that almost all real massive cargoes are launched IRL...

^^This

Launching 200 tons in two 100 ton packages and assembling in orbit is far easier, and actually can end up taking less time on slower computers since part count increases exponentially as you add payload mass. Not to mention the time saved by not engineering a 200 ton lifter.

I personally refuse to launch anything heavier than about 125 tonnes in a single launch.

[ZenithRising]

I just went through a similar episode myself. I was working with a moderately sized design (5 orange tanks, 4 mainsails, 12 solid boosters) that had been fine, and after some minor tweaks to the payload to try and reduce wobble on ascent, the whole thing started collapsing on the launch-pad. A few times it just split about halfway down, detaching my initial stages, without any visual change. It took me a long time to figure out why most of my engines weren't responding anymore .

Unfortunately I don't think I have a lot of insight to add. After messing around with a lot of strut configurations, I eventually got it to stay in one piece all the way up again. In the many configurations I tried, very small changes in configuration seemed to sometimes result in huge differences in outcome. I think ultimately it just comes down to quirks in the alpha build.

[allmhuran]

In my signature is a link to a video showing a lift of 750 tons (20 full jumbo tanks) into LKO.

The following video on my channel is a brief tutorial on the design, which I've dubbed a "thrust plate". Using this technique you can lift just about anything.

[ZenithRising]

In my signature is a link to a video showing a lift of 750 tons (20 full jumbo tanks) into LKO.

The following video on my channel is a brief tutorial on the design, which I've dubbed a "thrust plate". Using this technique you can lift just about anything.

Fantastic video. This one on staging is great too:

Does anyone know if struts add drag, or just mass? Can I add them more or less with impunity? Sometimes they seem to just make the situation worse.

[Musicrafter]

This is kind of an old thread, with an older version of KSP, but I'll pitch my design in for 0.90:

I have a ship I call the "Magnus III" (guess how many failed Magnuses there were before) that delivers 728 tons to LKO in just three stages. It weighs 5200 or so tons on the launchpad. My lifter just so happens to consist of stacks of three Rockomax orange tanks in an inner ring of six and an outer ring of twelve. All 18 stacks are thrusted by Mainsails. That alone isn't enough dV nor enough TWR, so I added eight 2.5-tall stacks of Kerbodyne tanks with the huge Kerbodyne quad engine on the bottom of each. And that was still not enough so I added four of the taller solid boosters (not the BACCs, they're the ones by Rockomax) to each of the Kerbodyne stacks. The ascent stage has just 100 dV left by the time it achieves a circular orbit.

I really tried to compact the design. I refused to use asparagus staging because of how close together all the tanks are. All the tanks expire at the same time. Remarkably, I also didn't use any fuel lines at all, so the outer Kerbodynes don't feed any of the Jumbo-64 oranges. But because of the proximity of all the tanks, it was easy to add a bunch of struts to hold things on radial decouplers in place. I never have any idea what I'm doing when I place struts; I just place them where it looks right. I took a series of screenshots of the ascent.

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I actually think I'm a relative noob at KSP. I've never left Kerbin's SOI, ever. The furthest I've gone is Mun. I know basic information about the Kerbol system, such as the 11 km/s Eve ascent requirement (and the 97km atmo) and the 5 km/s Tylo requirement, but I've never been there. This rocket was the most impressive thing I've ever made.

[Specialist290]

Musicrafter: I'm sure the OP would have appreciated the advice; however, as this thread has been dormant for a very long time and threads in this subforum tend to be rather time-sensitive, I'm afraid all your hard work will be for naught in this particular case. Please keep in mind that, while necroposting isn't necessarily against the rules as such, it's generally wise to let a sleeping thread lie if it's long since exhausted its purpose for existence, and we don't want threads containing potentially outdated information rising from the depths to confuse other new members. As such, we'll be closing this thread.

Don't take this as a knock against the quality of your contribution; it's just that sometimes, it's best to let a sleeping thread lie