orbital fuel transfer

[king of nowhere]

I have built a reusable lander to assemble a base on Mun. I called it the sky crane. the sky crane attaches to pieces in orbit, then it brings them on the surface and it goes to orbit again, ready to bring down another piece.

Of course, the sky crane needs refueling. here the troubles begin.

I launched a rocket with a new part to bring to Mun surface, and I connected it with the sky crane in orbit. Now I want to transfer the leftover fuel from the rocket to the skycrane before deattaching the parts I don't need anymore.

And I'm finding out I can't. I can't find any way to transfer fuel from the rocket tanks to the sky crane tanks.

Nothing is stopping fuel transfer, if i use the engines on the sky crane I consume fuel on rocket tanks, so that's not the problem. furthermore, I also can't figure out how to transfer fuel from one tank to another on the same ship, so it's definitely something to do with my ability to figure out how to tell the game that it needs to transfer fuel.

how do I give the commands to transfer fuel between different tanks on docked vehicles?

thanks

[Curveball Anders]

1 hour ago, king of nowhere said:

I have built a reusable lander to assemble a base on Mun. I called it the sky crane. the sky crane attaches to pieces in orbit, then it brings them on the surface and it goes to orbit again, ready to bring down another piece.

Of course, the sky crane needs refueling. here the troubles begin.

I launched a rocket with a new part to bring to Mun surface, and I connected it with the sky crane in orbit. Now I want to transfer the leftover fuel from the rocket to the skycrane before deattaching the parts I don't need anymore.

And I'm finding out I can't. I can't find any way to transfer fuel from the rocket tanks to the sky crane tanks.

Nothing is stopping fuel transfer, if i use the engines on the sky crane I consume fuel on rocket tanks, so that's not the problem. furthermore, I also can't figure out how to transfer fuel from one tank to another on the same ship, so it's definitely something to do with my ability to figure out how to tell the game that it needs to transfer fuel.

how do I give the commands to transfer fuel between different tanks on docked vehicles?

thanks

Normally you open the PAW on one tank and then alt-click on the other tank to open the PAW of that one.
That should give you the transfer options.

Edit:
Oh, and in career you need to upgrade the R&D building to get fuel transfer.

Edited May 31, 2020 by Curveball Anders

[Rhomphaia]

To transfer fuel open the PAW for both tanks involved in the transfer, (right click one tank then alt+right click the other) with more than one PAW open the out and in buttons should appear. click out on the donor or in on the recipient.

You can use this to share between multiple tanks at a time, so if you wanted to share fuel evenly from one tank into two, you would open all three PAW and use out on the donor tank. similarly if you wanted one tank to draw evenly from two donors, open all three PAW and click in on the recipient.

If you have trouble finding the tanks you need you can open the resources tab (up in top right) then check the checkbox for the resource you intend to transfer, this will open the PAW for every part that contains that resource. pin the ones you want then uncheck the checkbox to hide the rest.

 

Edited May 31, 2020 by Rhomphaia

[Superfluous J]

33 minutes ago, Curveball Anders said:

Normally you open the PAW on one tank and then shift-click on the other tank to open the PAW of that one.
That should give you the transfer options.

ALT CLICK ALT CLICK ALT CLICK.

Edit that quickly lest the poor OP accidentally throttle up after docking.

Why no that never happened to me. Multiple times. Becuase shift-click is baked into my muscle memory. Why do you ask?

[Curveball Anders]

2 minutes ago, Superfluous J said:

ALT CLICK ALT CLICK ALT CLICK.

Edit that quickly lest the poor OP accidentally throttle up after docking.

Why no that never happened to me. Multiple times. Becuase shift-click is baked into my muscle memory. Why do you ask?

Oops, thank you, fixed.

 

[king of nowhere]

3 hours ago, Curveball Anders said:

Normally you open the PAW on one tank and then alt-click on the other tank to open the PAW of that one.
That should give you the transfer options.

Edit:
Oh, and in career you need to upgrade the R&D building to get fuel transfer.

alas, that's not happening. I took a screenshot, sorry for the different language but there definitely are not in and out options. unless they are the arrows and the flux priority buttons, but i tried to do stuff with them, it never changed anything.

Oh, and i do have the tech center at level 2, and it says resource transfer available

https://imgur.com/a/ECs0A6N

edit: by the way, i also discovered that i can change the fuel level on the stage panel on the left by clicking on it, but it has no apparent effect. certainly if i move to 0 the fuel in the stage i want to empty and to max in the stage i want to full, nothing happens

 

Edited May 31, 2020 by king of nowhere

[4x4cheesecake]

Check your difficulty settings for "Resource Transfer Obeys Crossfeed Rules":

Spoiler

With this option enabled you are not able to transfer fuel through certain parts, mostly heatshields and constructural parts like this beam:

Spoiler

You can disable/enable this option at any time but if you want to play with this option enabled, you can always bypass the crossfeed restriction by adding two fuel lines, one for each direction. For examples, it's not possible to transfer fuel between these tanks because of this option:

Spoiler

But after adding a fuel line for each direction to bypass the beam, it works just fine:

Spoiler

(pay attention to the direction of the arrows on the fuel lines)

If you add just one fuel line, the option to transfer fuel will only appear on one of both tanks but it will still not work because the game tries to move fuel from one tank to the other but also to move "nothing" (let's assume some kind of gas to keep the tanks pressurized) in the other direction. Since the fuel line only transfer in a single direction, you need the second one for the other way

[king of nowhere]

great, very helpful.

Knowing that, I checked all the parts for fuel transfer, and i discovered that the only part stopping fuel transfer was the stage separator. which I can set to enable fuel transfer. once I enabled fuel transfer on the stage separator, I was able to transfer fuel between the tanks.

 

[4x4cheesecake]

Glad to hear it's working now