does RCS obeys crossfeed rules?

[antipro]

in this ss you can see all rcs thrusters are burning, while I have each relay tank turned off and the decoupler crossfeed is disabled.
relays rcs takes the monopropellant from the main vessel tank. and viceversa the main vessel rsc takes monopropellant from relay tanks starting from the higher to the lower.
is this normal that RCS doesn't obey the crossfeed rules?

Edited November 4, 2020 by antipro

[swjr-swis]

1 hour ago, antipro said:

is this normal that RCS doesn't obey the crossfeed rules?

Yes. Not all resources are treated equally in KSP.

In your KSP folder, check the file  GameData\Squad\Resources\ResourcesGeneric.cfg .

You'll see a list of all resources used in the game. One of the properties of resources is the 'flowMode'. You'll notice the flowmode of Monopropellant is different from LiquidFuel or Oxidizer, and that there's also other flowModes. Whether a resource flows at all, and if they obey crossfeed or not, is decided by this.

In good Kerbal tradition, this rather crucial information can only be obtained outside of the game.

Edited November 3, 2020 by swjr-swis
link

[Spricigo]

Well, I know it is not what you asked but you may actually be better swapping this RCS paraphernalia to a Oscar-B tank and a pair of ant or spider engines in  each satellite. 

 

 

[antipro]

11 hours ago, Spricigo said:

Well, I know it is not what you asked but you may actually be better swapping this RCS paraphernalia to a Oscar-B tank and a pair of ant or spider engines in  each satellite.

thx for the tip, I thought about it.
spider engines are lighter, more powerful and efficient than rv-105, so they are good for my purpose: circularize each relay as fast as possible.
anyway I still need RCS for precise fine tuning, so spiders+oscar-B will become an extra weight and space into the fairing.

[Spricigo]

2 hours ago, antipro said:

anyway I still need RCS for precise fine tuning, so spiders+oscar-B will become an extra weight and space into the fairing.

Only because you are going for ludicrous level of precision, for such a single RV-105 offset to the CoM is the way to go and extra weight you don't ditch before the circularisation can actually increase the precision.

For practical purposes spiders/ants can handle it just fine, people often don't even bother to get any lighter than the spark.

[swjr-swis]

7 hours ago, antipro said:

I still need RCS for precise fine tuning, so spiders+oscar-B will become an extra weight and space into the fairing.

Something to consider: all engines have a thrust limiter slider that you can adjust live in flight. So you could leave it full thrust for the initial transfer and capture burns and perhaps even the initial circularization, and then adjust it down (all the way to 0.5% if need be!) for precision orbit finetuning.

[DerkyJerkyWreaksHavoc]

@antipro yes. RCS follows the same cross feed rules as Liquid Fuel. Hope this answered your question.

[Snark]

17 hours ago, DAFATRONALDO2007 IN SPACE said:

@antipro yes. RCS follows the same cross feed rules as Liquid Fuel. Hope this answered your question.

Sorry... but this is not the case.  RCS does not follow the crossfeed rules.  See this excellent explanation by swjr-swis, above:

On 11/3/2020 at 4:47 PM, swjr-swis said:

Not all resources are treated equally in KSP.

In your KSP folder, check the file  GameData\Squad\Resources\ResourcesGeneric.cfg .

You'll see a list of all resources used in the game. One of the properties of resources is the 'flowMode'. You'll notice the flowmode of Monopropellant is different from LiquidFuel or Oxidizer, and that there's also other flowModes. Whether a resource flows at all, and if they obey crossfeed or not, is decided by this.