Jet engine center of mass

[Teilnehmer]

Having been playing KSP for years, I’ve just noticed that all stock jet engines (except the Goliath contained in its own nacelle) have their centers of mass shifted forward way beyond the part’s boundaries.

I suspect, this has been done as a way to compensate the absence of the engines’ bodies in stock KSP, so real life planes’ replicas could fly.

In the Realism Overhaul a different approach is used: engines actually have their bodies, not only the nozzles.

Spoiler

My first thought was that it’s a new bug/feature in 1.9.1. But it turns out that this have been so at least since 1.2.2 (I don’t have any 1.0.x—1.1.x installations so I cannot check them).

In 0.90, however, the situation was almost opposite: the jet engines’ CoM is at the rear tip of the nozzle for some reason:

Spoiler

 

This feature(?) was a complete surprise for me.
Are you guys aware of it?
Have anybody used it in an unusual way?

 

Edited April 23, 2020 by Teilnehmer

[HvP]

There's actually a cheaty trick to stabilize rovers on low gravity worlds by attaching a jet engine to the center and rotating it to point upwards. This moves the rover's center of mass unrealistically low, perhaps even below ground level, making it nearly impossible to flip over.

Edit to add: I see from your video that you figured out the same trick in a way, haha.

Edited April 23, 2020 by HvP

[Rhomphaia]

Oh the good old days, when Lift was magical, drag was exclusively dependent on mass, and jet engines could achieve escape velocity as long as they had intake air.

Having all the mass at the nozzle wasn't an issue back then, but as those things changed, it became one. So the mass shifted forward, but why make a model no-one will see.

[OHara]

The *.cfg for each jet engine refers to a model for the internal parts,
//  model = Squad/Parts/Engine/jetEngines/turbineInside
but it is commented out in each case.

You can remove the '//' comment indicators, on all lines in the MODEL blocks, if you want a visual model more consistent with the centers of mass.

Edited April 23, 2020 by OHara
image

[Teilnehmer]

47 minutes ago, Rhomphaia said:

So the mass shifted forward, but why make a model no-one will see.

I’d prefer full-sized engines, like in RO, but covered. Aircraft would be much less cheaty this way. One wouldn’t be able to make a plane with an engine nozzle sticking out from the cabin or a fuel tank.

Say,

Edited April 23, 2020 by Teilnehmer

[Rhomphaia]

the problem i would have with that is that since all the supersonic engines share the same form factor it is already pretty stifling to creativity, forcing nacelles would only make it worse.

Aircraft will always be cheaty anyway given the difference in scale between the planet and its atmosphere.