Stock Rotating Part Bug Help

[Sheiss]

Hey guys,

I haven't been on this forum in ages, decided I would return to KSP to try fix a ship which I got stuck on years ago because of some kraken-like issues. Alas, I got stuck again! I'm not sure where else to turn so I hope you guys are able to help:

I'm building a stock spaceship with a rotating turret. I've gotten the turret to work quite nicely, but whenever I leave and re-enter the session on the ship with the turret, the turret goes flying as soon as I undock it from the ship.

The axle of the turret is created by two rings of Cubic Octagonal Struts around Z-200 Rechargeable Battery banks with an FL-T100 in between to stop the axle from sliding up or down (see screenshot below). It uses an Advanced Grabbing unit to dock the turret with the ship for flight and time-warping. The grabbing unit works perfectly if I don't dock the turret to the ship when leaving a session and load straight back in. The problem with this is the turret then drifts from the ship if I timewarp in another session. Docking the two together prior to leaving the session results in the aforementioned kraken-like disintegration.

If you want to see what I'm talking about, you can get the craft file at: https://www.dropbox.com/sh/u947i804lhyt8aa/AABrxuIIYthtM4u1m4NsmFaxa?dl=0

You'll find the turret slot in the middle of the ship. There's a decoupler along the side of the turret (which is currently just Remote Guidance Unit) that initially connects it to the ship that you'll need to detach once in flight (you can see the decoupler on the right side of the screenshot below). You'll find the grabbing unit below the turret which you can arm to connect the turret to the ship. I then usually timewarp to get the decoupler to float out from inside the ship. You'll obviously need to cheat the ship to orbit to test this as I haven't included a launcher.

I've also tried a variation with a Clamp-o-tron Shielded Docking Port instead of the grabbing unit, but with this I can only seem to dock and undock it once, then it refuses to reconnect the turret.

Thanks for reading, looking very much forward to your responses!

 

Edited April 11, 2020 by Sheiss

[OHara]

Welcome back. 
(I couldn't properly load the craft because of  a part from a mod that I don't have, but I think I get the idea.)

Generally, stock bearings cannot survive load/save or time-warp, as you say, because the two parts are separated craft and KSP puts them on their individual non-interacting orbits, which drift apart during time-warp.  When time warp is over, the individual craft find them selves in the same location, and act as if they had been forcefully placed there and spring apart violently.

Your redockable rotation bearing is a good way to success; just re-dock it before any time-warp.  See the craft here and the thread here for similar solutions.

Offset the stack-separator in the VAB, and offset back the parts attached to, it so that the separator alone is outside the craft.  Then you don't need the time-warp trick when you decoupler.

There are of course mods like 'Infernal Robotics' that provide bearings and Squad themselves now sell a robotics mod called 'Breaking Ground' if you want to build this more simply.