Spontaneously exploding aircraft design

[R4P70R]

Hello,
I didn't tried to create anything crazy in term of design in the plane but I think there is a bit of a problem with this particular plane.
And yes, I can reproduce this "thing" on every single flight.

 

 

I can share the design if needed.

1.8.1.2694 WindowsPlayer x64 en-us
(not sure if these 2 qualify my install to modded or not)
1.8.1 Making History
1.3.1 Breaking Ground

Win 10 Pro 1903/18362.476
i7-5820K
16GB
GTX1080 / 441.20

[Gordon Fecyk]

Nice. Air breathers to space.

Seriously, those clipped-in Mk0 fuel tanks into the swept wings remind me of a problem I had with a cargo space plane early on. Clipping tanks into wing parts gave me trouble if there was any flex in the wings. A set of struts or two could help, or Autostrut on the wings and tanks if you have Advanced Tweakables enabled.

I'll try reproducing the craft from your video to see what happens.

[R4P70R]

I just tried with a bit of structs...
It doesn't seems to make any difference (well if you don't take into account the fact that i'm going to Duna now)

 

[Gordon Fecyk]

Aside from centre of mass issues, the plane seems OK:

I had to move the nacelles further back to move the centre of mass closer to the centre of lift. It could also stand additional control surfaces at the rear.

But it does seem to fly. No Autostruts used aside from the mandatory ones for the landing gear.

By any chance do you have "Same Vessel Interaction" enabled on any of these parts?

[Update] One thing I goofed on my first design: The four front engines' thrust vector intersects with the rear tail planes, so I had to lower the front nacelles ever so slightly to get the intended thrust. Raising the rear tail planes, or using Tail Connector B, or rotating Tail Connector A slightly to emulate Tail Connector B, would prevent this as well.

Edited December 10, 2019 by Gordon Fecyk
Adjustments to fix thrust problem

[R4P70R]

Ok litte update. After trying to remove as much as possible pieces from the design, I narrowed down the piece that is fiddling with the physics.

Moving them with the translate tool doesn't seems to help
Re-rooting them make the game crash
Removing them give me this error

So there is obviously something wrong with my file. It may have been corrupted somehow.

Nothing wrong with the design if I design it again like you did but clearly a bug somewhere that made the file corrupted.

 

Here is (just for fun) the behavior of the simplest plane: