TIL Fuel Flows Radially

[Moesly_Armlis]

The fuel flow logic has interesting quirks. Engines attached axially to a tank of oxidizer attached radially to a tank of liquid fuel normally does not work but by logic Bill:wink: can make it so.

This example shows that liquid fuel flows radially out by fiddling with the control valves.

Turn off the valve of the resource needed.

Not sure if this is a bug or a featurette but kinda hoping on the latter. Bill:huh: thinks it is something only engineers should be allowed to do.

Pictures of the testing:

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I am not sure how this can be useful but I am continuing to experiment. Oxidizer also flows the same way.

[EladDv]

It's caused because of how KSP parts are arranged (i think), because they are arranged in a tree the code that takes the fuel always goes from left to right (or the opposite i can never remember) and thus the first side will drain fuel first and leave non for the other engines

[Alshain]

I was unable to reproduce this. Are you sure you don't have a mod, Crossfeed Enabler for example?

EDIT: n/m I got it to work. Yeah I'd say a bug in the logic that searches through the part tree for available fuel. At some point it forgets to check for crossfeed. There really is no advantage to using it. It's a lot of trouble for something you can do easier with fuel lines.

Edited October 12, 2015 by Alshain

[BudgetHedgehog]

At some point it forgets to check for crossfeed.

KSP 1.0.4, ladies and gentlemen, a full release, non-Early-Access game that has code that forgets to check if the part is supposed to actually behave like it's supposed to.

Sorry, still sore over the asinine jet engine fuel flow behaviour.

[Alshain]

KSP 1.0.4, ladies and gentlemen, a full release, non-Early-Access game that has code that forgets to check if the part is supposed to actually behave like it's supposed to.

Sorry, still sore over the asinine jet engine fuel flow behaviour.

Sure, when you clip the comment and take it out of context it sounds that way. The rest of post details how it doesn't affect anything. Even if it did, you can't blame them for missing the ridiculous set of steps it took to reproduce it. I had a hard time finding it too.

[MockKnizzle]

Wow, a game has a bug in it! What kind of awful, horrible world do we live in, and how dare SQUAD allow such a thing to happen while you're on watch!

Neither time nor resources are infinite, but player expectations are. Developers have to do the best they can to find a balance. Bugs are a normal result of these constraints.

[Moesly_Armlis]

After testing this it seems the fuel tanks function as fuel ducts to the adjacent tank.

The only other useful purpose this has is during an extreme hard career and have not unlocked external fuel ducts or fuel transfer. I am still in favor of this and do not see it as a bug so long as engineers are the only class able to enable.

[KerikBalm]

That seems to be what screws over this Duna ISRU ship.

http://forum.kerbalspaceprogram.com/threads/135871-Fuel-Drain-bug

The ship becomes massively imbalanced, and fuel drains in opposition to what it should based on the fuel lines... shutting off fuel flows and using manual transfers is the only option.

If I didn't have fuel lines from the center, it would be completely unflyable because of this bug.

[Padishar]

No, this is not a bug, it is a deliberate part of how the stack search flow mode works. I'm on mobile so can't find the link at the moment but Kasuha's fuel flow thread gives full details of how the system works and specifically mentions this part.

As for it being the cause of a problem with an ISRU ship, there is a different bug in the RequestResource mechanism that causes serious issues if you try to run engines while running an ISRU process. Again, mobile makes finding a link tricky but I think it is bug 5136 on the tracker.

[Red Iron Crown]

The fuel flow rules thread Padishar is referring to: http://forum.kerbalspaceprogram.com/threads/64362

I think the related bug reports are 5132 and 5408.