radial decoupler: mass remaining post-decoupling

[Kerbocracy]

Hey all,

anyone know the answer to the following question: when radial decouplers decouple, how much mass do they leave no the parent piece? They appear to leave little nubs. I wonder what fraction of the original decoupler mass these are.

The same question might be applied to struts - when struts are broken, where does the mass go? I'm assuming it stays with the parent node...

[Mmmmyum]

The decouplers mass goes to the decoupled part I've found, not sure about the struts though. (Had a craft that had it's return pods mounted on top of the main nuclear boosters)

[Collin Dow]

Make a rocket with known mass. Add decouplers, note the addition of mass. Launch, and blast off the decouplers, note the total mass. A little math, and you have your answer.

So basically...I don't know off the top of my head, but at least it's easy to find out.

[numerobis]

The mass of the struts is zero at all times.

The mass of decouplers goes to the decoupled bit. On the probe decoupler, that's the part the triangle points towards away from. The nubs are just cosmetic.

Edited November 4, 2013 by numerobis

[Kerbocracy]

The mass of the struts is zero at all times.

The mass of decouplers goes to the decoupled bit. On the probe decoupler, that's the part the triangle points towards. The nubs are just cosmetic.

Thanks for the replies. Struts really have zero mass? I feel like adding struts changed my dV... Have to check again. If struts are free, then I'm going big on them. Also good that the mass goes with the decoupled piece. But for probe (stack?) decouplers, I think the body of the decoupler (at least graphic) stays with the part that is at the base of the arrow - I point the arrow towards the probe/engine, and that part detaches cleanly, seaming to leave the rest of the decoupler with the parent. But maybe the mass goes with the probe anyway despite the graphic?

[Kerbocracy]

Make a rocket with known mass. Add decouplers, note the addition of mass. Launch, and blast off the decouplers, note the total mass. A little math, and you have your answer.

So basically...I don't know off the top of my head, but at least it's easy to find out.

thanks buddy; I'm asking because a) I'm too lazy to do it myself and I assume that with all nerd wisdom available here, someone will have tried it. The good thing about sharing knowledge in writing is that everybody doesn't have to redo every science experiment from scratch.

[Sirrobert]

The nubs left over atleast have 0 mass. I'm not entirely sure about struts, but I think they are also massless in flight

[DMagic]

Struts and fuel lines have zero mass in-flight. Just put a thousand of them on and check if you want to be sure, have fun waiting for it to load though.

The nubs that get left behind also don't have any mass, this goes for struts and decouplers. If you want to get rid of the nubs just save and reload, they should all disappear. The only exception is when you keep the start point for a strut. This is why you should also start your struts on the part that gets removed (put them on the lower or radial stages and connect the second point to the upper or inner section). These strut start-point nubs won't add to your mass, but they will add to your part count, so make sure the start point gets left behind, not the end point.

[numerobis]

But for probe (stack?) decouplers, I think the body of the decoupler (at least graphic) stays with the part that is at the base of the arrow - I point the arrow towards the probe/engine, and that part detaches cleanly, seaming to leave the rest of the decoupler with the parent. But maybe the mass goes with the probe anyway despite the graphic?

Oops, no, you're entirely right -- I just had a brain fart is all.

[Collin Dow]

I would have done it, but I was on my way out the door.