Counterweights though Tweakables

[HQtopgun1]

I was thinking after horribly crashing a spaceplane due to unbalanced fuel draining, that small counterweights could be implemented as radial tanks that hold a dense fluid. And the amount in each tank could be manipulated through tweakables. In flight, you could also set up and action group or just begin manually pumping the fluid between the tanks (increasing/decreasing their mass) to deal with unbalanced fuel draining.

[Master Tao]

I'm not sure what problem this solves that shifting fuel around wouldn't solve with less dead weight. Better stock control over fuel balance would help.

Could you show an example where this would help?

[Sirrobert]

Sounds like you simply need to rethink how you design your rockets, rather than inventing another part to fix your improperly designed things

[Murph]

I agree with Master Tao and Sirrobert, we don't need this, as dragging dead weight around is rarely a good aerospace solution (although I acknowledge that it has been done with, e.g., the "Blue Circle" concrete not-a-RADAR for the Panavia Tornado). As long as the fully fuelled CoM is adjusted to be a little ahead of the CoL, the same result is achieved by active management of your fuel load (either using stock fuel enable/disable and transfer, or one of the fuel balancer mods).

Yes, the stock game probably does need better dynamic fuel management in the long term.

[thereaverofdarkness]

I'm not sure what problem this solves that shifting fuel around wouldn't solve with less dead weight. Better stock control over fuel balance would help.

Could you show an example where this would help?

There is one case in particular: planes. The engines are very dense and their mass is all at the back of the plane. The cockpits are oddly light. This leads to KSP planes having their center of mass disproportionately far back toward the rear end, often making it difficult to put the center of lift behind the center of mass and still be using stabilizing fins on the nose. It doesn't make sense that a plane should have its center of mass as far back as 20% from the rear end.

Of course, a better way to solve the problem would be to increase the weight of cockpits, and distribute engine weight further into the center of the plane (much like real planes), or just cheat and make them lighter. But I'd still like having a counterbalance option. Even just a radial object that is small yet fairly dense would do it. I'd use the radial RCS tanks but they're often too big.

[Kegereneku]

Just to say : Real airliner does balance their CoM through fuel. (and trim)

I have no idea to help balancing spaceplane but I think it would be better to give players the tools to balance most plane, than change part spec with the risk of accommodating only a few design.

Of course there could be both, an easy fix that cover what player usually build, and the tweakable fix for those wanting to make incredible design.

[Ikaneko]

I had a similar problem but I managed to solve it by shifting the fuel into forward tanks on reentry.

[Murph]

I had a similar problem but I managed to solve it by shifting the fuel into forward tanks on reentry.

Yup, that's the standard technique. While it's possible to design static-CoM craft, there's really no need to do so, only to ensure than the fully fuelled and dry CoMs are both forward of CoL, and that the tank layout permits moving fuel forwards before reentry. Some would advocate ensuring that CoM is always forward of CoL, but that's not necessary either, only to ensure that it's possible to keep CoM in front of CoL during atmospheric flight (i.e. if your orbital burns pull CoM back behind CoL, it doesn't matter at all). Designing to keep CoM always forward can cause the undesirable compromise of having it too far in front of CoL when fully fuelled.