Radial decouplers, only half attach.

[Wingnutt]

Basically anytime I try to use radial decouplers, any kind for trying to attach anything in any way.. only the bottom ones actually connect..

For example say I have a bunch of fuel tanks and a mainsail at the bottom and I want to attach 2 anything, any booster or anything else to the side of it with radial decouplers.. any radial decoupler.. doesn't matter which ill put a decoupler at the bottom and one further up so I have 2 attachment points.. everything looks perfect in the VAB, go to the launch pad and the boosters are hanging off because only the bottom decoupler is actually attached.

Have tried different iterations over and over and it is 100% every single time it does this, without exception.

Example

Looks good

Reality

what is the deal?

[rofltehcat]

Ships are built in the form of a tree because it makes the coding and integrity calculations much easier. This means that any part can only be connected to one parent part but several children parts can then be attached to that part. Think of the branches of a tree. (No programmer, so my explanation/jargon probably isn't 100% correct.)

This means what you are trying to do is impossible. You can only ever use one decoupler. For additional stability you will need to use strut connections.

[Wingnutt]

Gotcha, looks stupid as hell but I guess if thats the olny way to do it.

[tutike2000]

This means what you are trying to do is impossible. You can only ever use one decoupler. For additional stability you will need to use strut connections.

It is an (intentional?) limitation of the VAB interface, it is theoretically possible to save your craft and edit the .craft file to achieve this (at least it is possible for node-attached parts, like tricouplers). But yeah, add struts instead, it's a lot easier.

[UnusualAttitude]

KSP doesn't allow multiple connections between parts, you're not doing anything wrong, it's just a limit of how the game engine considers the connections between parts of a vehicle.

Forget the second set of decouplers and add some struts attaching from your boosters to the core.

[nekogod]

You can't do this, each part connects in a tree like pattern so part 1 connects to part 2 which connects to part 3 etc you can't create loops.

The exceptions are docking ports, struts and fuel lines

[tutike2000]

KSP doesn't allow multiple connections between parts, you're not doing anything wrong, it's just a limit of how the game engine considers the connections between parts of a vehicle.

Forget the second set of decouplers and add some struts attaching from your boosters to the core.

You mean that the ingame part editor doesn't allow multiple connections. I'm pretty sure that the game engine itself does. Will need to create a bendy craft to prove whether this is actually true or not.

[Warzouz]

Yes, that's a pain. It's really a problem when you want to create engine clusters with mutli-couplers. You can't put them vertically.

[lazaruz76]

Wingnut,

one way around this small issue if you want the "look" is to build it the way you have, launch the craft to find out which part does not connect, revert, then use the offset tool to move the parts out away from each other, place a strut directly between the 2 parts, then move them back together. This would give you the "look" and hide your struts. This is the same technique that I and a lot of others use to "stitch" together large wings on planes.

[Sharpy]

Also one fundamental thing most newbies don't know, that keeps them from using the struts:

Struts detach (break) when the strutted part is decoupled. So don't worry that side booster will dangle on a strut once the radial decoupler is activated. It won't. The strut will vanish.

[Kryxal]

It's worth noting that fuel lines are ALSO struts. That craft would work well if you used fuel lines from the top of the radial tanks to the center stack, and that would allow you to use the center engine as well on launch (which may or may not help, depending on ISP).

[Snark]

Also one fundamental thing most newbies don't know, that keeps them from using the struts:

Struts detach (break) when the strutted part is decoupled. So don't worry that side booster will dangle on a strut once the radial decoupler is activated. It won't. The strut will vanish.

This.

Also: when placing the strut, put the 1st endpoint on the thing-being-decoupled (e.g. the radial tank), and the 2nd endpoint on the thing-it's-decoupling-from (e.g. your central rocket body). In other words, attach them in the opposite direction from the way you do decouplers: inwards from the outside, rather than outwards from the inside.

Reason: In 1.0 and after, struts actually have mass (and it's significant). That mass stays with the first endpoint. So if you start your struts on the piece being decoupled, then that means you're dropping the strut mass, too. If you put your struts going from the inside outwards, then you keep that mass on your ship even after your decouplers fire, which will cost you dV.

[jkool702]

This.

Also: when placing the strut, put the 1st endpoint on the thing-being-decoupled (e.g. the radial tank), and the 2nd endpoint on the thing-it's-decoupling-from (e.g. your central rocket body). In other words, attach them in the opposite direction from the way you do decouplers: inwards from the outside, rather than outwards from the inside.

Reason: In 1.0 and after, struts actually have mass (and it's significant). That mass stays with the first endpoint. So if you start your struts on the piece being decoupled, then that means you're dropping the strut mass, too. If you put your struts going from the inside outwards, then you keep that mass on your ship even after your decouplers fire, which will cost you dV.

Also, and I find this equally or more important since I tend to build part heavy ships, doing this keeps the strut part count with the detached endpoint, which can lead to a significant reduction in part count (and lag) on big ships.