Wait.. that can't be right... CoM bug in SPH?

[allmhuran]

Adding more weight behind the CoM is moving the CoM slightly forward as shown in this Gfy:

http://gfycat.com/GlossyInstructiveEyra

[sal_vager]

The CoM of the jet engines was moved forwards to help reduce the effect of having what was essentially a really heavy exhaust nozzle with no actual engine mesh hanging off the back of our planes, the changed CoM simulates where the engine would be.

So you'll see this effect depending on where your crafts CoM is

[allmhuran]

OK, that's interesting. I don't particularly disagree with the reasoning but it's a bit... odd. I believe there are a few parts with mass that behave in odd ways (heatshields have been mentioned). I have no suggestions on how to make that more intuitive but it certainly caught me out!

[Kegereneku]

Interesting indeed, maybe disorienting as we came to expect CoM to change with mass.

I wouldn't know either how to make it more intuitive...

[sal_vager]

Well, my choice would be to have an actual engine, not just a nozzle, but still have the attach node where it is currently so the player sees the bulk of the engine in going in the craft.

But it'd be unnecessary and poke out of many builds.

[leopardenthusiast]

Sounds like you could do some odd things with this - for instance, a craft with its CoM fully ahead of all of its parts.