Liquid Stage Cross-feeding

[cray]

Hello. I've been using the following part modification from this website:

---

In order to make liquid fuel tanks attachable: open the part.cfg in *\Parts\fuelTank\ with notepad and add

node_attach = 0.0, 0.0, -5, 0.0, 0.0, 1.0, 1

under node definitions and change the attachment rules to

attachRules = 1,1,1,1,0

---

With version 0.8.5, fuel now flows across stage couplers. However, I've found that this means that a central tank feeds boosters. As a result, when the boosters drop off, the core is dry. The general idea I've seen in aerospace literature is rather the opposite: liquid boosters feed the core engines so that the core can carry its own mass but, once staged, the core has a full tank of gas.

How do I reverse the fuel flow from boosters to the core? Is there a part file modification to make?

[Coldie]

Where is the node_attach?

[HarvesteR]

This is mostly the reason why fuel tanks don't attach sideways yet. The fuel crossfeed feature still has a big limitation. It doesn't search 'upward', it searches parentward, that is, it will ask the parts it's attached to for fuel, and that will ask it's own parent part and so on.

So if you connect a fuel tank sideways to a radial decoupler, the decoupler is the tank's parent, and it will go that way for fuel. If there are any other fuel tanks stacked above the tank, they will be ignored since they're actually children of the first tank.

This has yet to be corrected. Once it is, there's no reason to keep fuel tanks from attaching sideways.

Cheers

[cray]

Where is the node_attach?

You manually write (or copy-and-paste) 'node_attach = 0.0, 0.0, -5, 0.0, 0.0, 1.0, 1' into the part.cfg file in the directory *\Parts\fuelTank\

This has yet to be corrected. Once it is, there's no reason to keep fuel tanks from attaching sideways.

I look forward to it. Cross-feeding is a useful feature for two-stage-to-orbit configurations. I don't suppose toggling the cross-feeding on/off (or using connectors with and without cross-feeding) will be possible?

[Braun]

So if you connect a fuel tank sideways to a radial decoupler, the decoupler is the tank's parent, and it will go that way for fuel. If there are any other fuel tanks stacked above the tank, they will be ignored since they're actually children of the first tank.

This has yet to be corrected. Once it is, there's no reason to keep fuel tanks from attaching sideways.

I don't see why this is a problem if I don't want to split up the fuel among the child engines.

[foamyesque]

I don't see why this is a problem if I don't want to split up the fuel among the child engines.

It results in tanks there is no way to burn fuel from.

[Krenn]

This is mostly the reason why fuel tanks don\'t attach sideways yet. The fuel crossfeed feature still has a big limitation. It doesn\'t search \'upward\', it searches parentward, that is, it will ask the parts it\'s attached to for fuel, and that will ask it\'s own parent part and so on.

So if you connect a fuel tank sideways to a radial decoupler, the decoupler is the tank\'s parent, and it will go that way for fuel. If there are any other fuel tanks stacked above the tank, they will be ignored since they\'re actually children of the first tank.

This has yet to be corrected. Once it is, there\'s no reason to keep fuel tanks from attaching sideways.

Cheers

anyway to just make all flows go in reverse? other than possibly having \'full\' tanks in strange positions on the stack, possibly throwing of center of gravity, i think it would work...

[Braun]

It results in tanks there is no way to burn fuel from.

That I understand, but try to build a rocket with liquid boosters that mirror the shuttle\'s launchcraft boosters.

Yeah, they\'re probably solid boosters, but 'our' solid boosters can not be sized up for this and decouplers would make our crafts at least three times as heavy.