Vanishing struts?

[GoDores]

I'm having a problem with a new super-heavy lifter I'm trying to build. Basically the struts that support the payload vanish as soon as I hit the launch button. The decoupler between the booster and the payload of course fails immediately and the booster destroys the payload.

Screenshots:

In VAB

On the pad, throttled up, ready for launch

Immediately after launching

Is this a bug or is something else going on? More importantly, how do I keep it from happening?

Edited October 9, 2013 by GoDores

[Luxmaster-CZ]

When decoupler fails, it separate your craft into two. And two separated crafts cant be bound by struts.

The upper stage is just too heavy, that it crush the decoupler under it, and struts then just disappear, as they would be connecting 2 crafts

[Kasuha]

I don't think it's decoupler failure. My guess is that docking port Sr separated from the rest of the payload. They do it all the time to me.

Press F3 to check which part has failed.

[GoDores]

Thanks. It does appear the payload was separating from the booster and causing the struts to vanish. Additional strutting fixed that problem. Unfortunately the booster design itself had a fatal flaw and I'm having to start over.

[tstehler1]

Good God... This ship is a slideshow producer if I ever saw one! (at least on my system) But quite cool.

[Blue]

It's very hard to get weight spread out for loads heavier than 200t (four orange tanks). Try making the payload an integral part of the launcher, rather than something that rests on top of it.

This is a picture of a launcher I built to transport a Tylo/Laythe Lander with accompanying pre-docked Jool transport. Notice how the payload is in the middle, and the launcher is configured like a large set of strap-on boosters.

[lajoswinkler]

There is no need for that much LV-N engines. It makes the stage extremely heavy, no wonder it crushes struts.

[DerekL1963]

It's very hard to get weight spread out for loads heavier than 200t (four orange tanks). Try making the payload an integral part of the launcher, rather than something that rests on top of it.

My heavy tug launches the same way... with a .3 T/W ratio at launch, it's foolish to carry it as pure cargo. Instead, it's the core of an asparagus system.

Tug, with the launcher wrapped around it, in the VAB.

On orbit.

[Spyritdragon]

Good God... This ship is a slideshow producer if I ever saw one! (at least on my system) But quite cool.

---------> Whackjob

[lammatt]

pancake...

i wonder why people do i,

it's super ugly and makes absolutely no sense aerodynamically...

why dont people just buid big crafts in orbits by joining smaller bits together?

[GoDores]

So I did finally get things worked out. Further strutting of the payload kept the stack from failing in the center, and after modifying the booster I got a successful launch.

On pad:

Payload in orbit:

To answer the questions in this thread:

-The final payload to LKO was about 306t. Mass on the pad was about 2200t and 950 parts. I was getting 1 to 2 FPS on launch; MJ was needed to fly it to orbit.

-I was testing the thrust plate design because of the limits of the strength of radial attachments. I've launched up to about 150t with pure asparagus designs but as I got bigger it became increasingly difficult to make a stable launcher. The thrust plate design does seem to be a stronger method of launching heavy payloads, although it still needs a lot of strutting.

-The staging was onion, mainly to save on build time. If I had made the booster pure 2x2 asparagus it would probably be a little more efficient, but I didn't want to spend the time setting up the staging. 8 orange tanks and their engines drop off with each stage.

-The 12 LV-Ns are less than 10% of the payload mass. They're there to achieve reasonable interplanetary burn times with very large payloads docked to the stage.

-The game doesn't currently model aerodynamics very well, or allow for orbital construction (other than docking). When those are implemented, I'm sure everyone's designs will change.