Why is this payload so damn bendy?

[Second Hand Rocket Science]

https://imgur.com/a/umaHRQo

It is pretty long, but it's all auto strutted and has rigid attachment enabled. It doesn't bend without the launch vehicle but as soon as I add the launch vehicle it becomes reminiscent of a wet, floppy noodle you find at the bottom of the bowl. See attached video:

 

Don't worry, I'm not planning to fly to Minmus without a fairing, but it's much easier to see the noodleness without it.

If for whatever reason you're interested in what it is, it'll be a habitation module for my first ever Minmus base. I'm not expecting it to work, since I've never done a space base ever, but I hope to teach myself at least how to do precision landings and if all goes well how to use an albeit primitive skycrane.

What do I do to fix this? Manually put on some struts? Connect the base of the module to the fairing via a larger structural piece? Or is this just too long and spindly to be launched in a single go?

[Lt_Duckweed]

Are you using grandparent autostrut? It's practically useless for stiffening in cases like this.  Autostrut a few parts on the payload to heaviest, and a few of the parts on the rocket/side boosters to root.

[Second Hand Rocket Science]

4 minutes ago, Lt_Duckweed said:

Are you using grandparent autostrut? It's practically useless for stiffening in cases like this.  Autostrut a few parts on the payload to heaviest, and a few of the parts on the rocket/side boosters to root.

I don't usually change from the default autostrut, just do to heaviest all the time. Payload is heaviest, and rocket isn't really the issue here, but I'll strut the boosters and launch vehicle to root and see if it makes any difference

Making the boosters strutted to root just made them noodle too and clip into the main fuel tanks. 

[Second Hand Rocket Science]

I thought I had cracked it by moving the very heavy fuel filled skycrane to the bottom instead of the top, but it didn't make any difference. I suppose it actually didn't make any difference to the CoM in the first place as the indicator is almost slap bang in the middle of the big science habitat bay thing, which is in the center of the entire craft. So I'm stumped

[king of nowhere]

6 hours ago, Second Hand Rocket Science said:

https://imgur.com/a/umaHRQo

It is pretty long, but it's all auto strutted and has rigid attachment enabled. It doesn't bend without the launch vehicle but as soon as I add the launch vehicle it becomes reminiscent of a wet, floppy noodle you find at the bottom of the bowl. See attached video:

 

Don't worry, I'm not planning to fly to Minmus without a fairing, but it's much easier to see the noodleness without it.

If for whatever reason you're interested in what it is, it'll be a habitation module for my first ever Minmus base. I'm not expecting it to work, since I've never done a space base ever, but I hope to teach myself at least how to do precision landings and if all goes well how to use an albeit primitive skycrane.

What do I do to fix this? Manually put on some struts? Connect the base of the module to the fairing via a larger structural piece? Or is this just too long and spindly to be launched in a single go?

there are times when the game does not make struts across docking ports. not sure when it happens; i know it's a bug of some editions. so, no matter how much you autostrut, it won't strut the payload to the rest of the rocket.

which also explains why, before you add the rocket, the payload is fine.

you can check it out, somewhere in the alt-f12 menu there is a "show autostrut" function.

easy fix: add a normal strut. it's just 50 kg. you'll remove it later with eva construction.

Edited March 3 by king of nowhere

[Second Hand Rocket Science]

7 hours ago, king of nowhere said:

there are times when the game does not make struts across docking ports. not sure when it happens; i know it's a bug of some editions. so, no matter how much you autostrut, it won't strut the payload to the rest of the rocket.

which also explains why, before you add the rocket, the payload is fine.

you can check it out, somewhere in the alt-f12 menu there is a "show autostrut" function.

easy fix: add a normal strut. it's just 50 kg. you'll remove it later with eva construction.

I made it a lot better by making the 1.6 megaton slightly oversized launch vehicle 3.75m instead of 5m, but it is still bendy enough to throw off maneuvers in the upper stages. The strut thing hasn't helped, probably since you can't directly mount struts onto a docking port radially. It is now possible to get to orbit without RUD, but trying to make delicate orbital adjustments to get a Minmus encounter is quite literally impossible. 

https://imgur.com/a/wtO5dGu Redesigned launch vehicle and payload. Heavy skycrane will be sent separately. Obviously with the fairing removed. 

[king of nowhere]

7 hours ago, Second Hand Rocket Science said:

 The strut thing hasn't helped, probably since you can't directly mount struts onto a docking port radially.

have you tried sticking them not on the docking port itself, but on the fuel tanks above it?

[Second Hand Rocket Science]

On 3/3/2024 at 3:46 PM, king of nowhere said:

have you tried sticking them not on the docking port itself, but on the fuel tanks above it?

That is exactly what I have already done