Quick ask: How do you attach extra tanks/engines radially to a rocket as per the KSP2 loading screenshot

[mrjsonkerbal]

Hi. I'm pretty new to the game and really struggling with something basic once I've started making slightly bigger rockets like those required to go beyond the mun and minimus. See below, this rocket from the loading screen - how are all of those side engines / tanks attached to the main rocket? When I do something similar, they fall off at launch, shortly after launch, or at some point on my way to orbit. I don't see any struts in use on that picture. How do you add those tanks / engine combination radially to the main rocket and have them "stay on." ?

Things I've tried:

1. Set radial symmetry to 6 and just put them where the selection tool allows them to go around the main fuel tank

 -  they tend to just fall off

2. Do that but then use the move tool to move them in slightly so they overlap the "main" center fuel tank a bit. 

  - they tend to just fall off

3. Add lots of struts

- This works some times, but as per the image below they are not required.

So what thing don't I know how to do? What makes those boosters securely attached to the main body of the rocket?

Thanks so much.

[K^2]

Generally, you'd place these on a radial decouplers, so that they can be jettisoned, not attach them directly to the main body. They will wobble quite a bit if you don't add struts, though. I would add at least one strut near the bottom of the side tank and one near the top, connecting it to the central body. All of this, starting with placing the decouplers, should be done in 6-way radial symmetry mode.

I have seen a symmetry mode bug where physics joints just aren't created, but that tends to happen when you try to build a sub-assembly with its own symmetries, then attach the sub-assemblies in a symmetry mode. Hopefully, that gets fixed, as it's annoying. But simply building out the side tanks in place seems to work just fine.

[Scarecrow71]

There are probably decouplers involved here.  You'd attach the decoupler (radial, probably the manifold) and then attach the tanks to the decoupler.

Edit:  darn you @K^2 and your ninja ways!

Edited May 5, 2023 by Scarecrow71

[MechBFP]

While a decoupler will help in this situation, and make your rocket much more efficient, this is something that should work anyway and is an example of something that KSP2 should have done much better than the first game to allow it to be more friendly to new players. 

[Lyneira]

Efficiency of staging aside, it should be possible to just directly attach fuel tanks to the side of a main tank and have them work. In fact it should result in a more stable connection than using a decoupler in between. If this is not happening right now, it might be a problem with the tuning of the game's part connection physics at higher masses. I don't build big often, but I have noticed spontaneous disassembly like that with one craft where I needed a big launcher.

Edited May 5, 2023 by Lyneira

[twich22]

Bottom line: you need struts. If that ship on the loading screen were flight worthy then it has struts. The struts are likely hidden on the surface that is contacting the main rocket. There is no other way to “securely” attach multi-part radial assembly’s without using multiple docking ports, which right now are bugged and don’t work right. 
 

The only other alternative would be to have no gimbal enabled on any of the radial rockets to minimize instability and to fly straight vertically through the atmosphere, but even then I’m not sure it would work. 

Edited May 5, 2023 by twich22

[mrjsonkerbal]

Hi. Just wanted to say thank you for all the thoughtful responses. I still a little disappointed that you can't easily join fuel tanks radially to a central bigger tank directly but I understand the decoupler efficiency point and struts seem to be a central part of the experience to just get used too.

[Meecrob]

[snip]

No, you don't clip radial boosters into the central stage, you place radial decouplers on the central stage and attach radial boosters to them. How else do you stage them when they are empty? Also you describe "asparagus staging" this is a strategy that many employ, but is not necessary to make a  rocket with a core stage and radial boosters.

Edited May 15, 2023 by Vanamonde

[darthgently]

6 minutes ago, Meecrob said:

No, you don't clip radial boosters into the central stage, you place radial decouplers on the central stage and attach radial boosters to them. How else do you stage them when they are empty? Also you describe "asparagus staging" this is a strategy that many employ, but is not necessary to make a  rocket with a core stage and radial boosters.

Additionally, offsetting parts to clip into their parent part does nothing to make the connection stronger

[Meecrob]

It makes the connection to the kraken stronger lol.

 

I'm just joking, but seriously, to the OP, I don't know exactly how you are building this rocket, but generally, if you want a part to drop off your vehicle, you have to have a decoupler of some sort. If you clip it in, it won't be able to be dropped when empty.

Edited May 12, 2023 by Meecrob