Aircraft Engine smoke

[Fadly]

I build a plane with "wheesley" turbofan engines. As I take off and climb, I noticed at some point, the smoke that came out of the engine suddenly disappear. By the time I'm cruising at 10,000 meters, there's no smoke except ofr a few occasional puff. I've been wondering if this smoke indicate something like an incomplete combustion, or is it just a decoration?

[KerikBalm]

It could be there are only a certain amount of "particles" generated, and by the time you're cruising at 10,000 meters, you're going much faster, and the particles are much more dispersed

[Adenosine Triphospate]

Unless there's a flameout, engines release particles at exact intervals. Basically what @KerikBalm said, because you're covering more distance in a given time, the particles are released further apart. When you are moving slower, the particles are released closer together as you have covered less distance.

For example, this (badly designed - its just one of my random screenshots) ship is going at 297 m/s. Say if the particles are released 5 times a second, that means that the 5 particles will be spread across the 297m it has covered, (a particle every 59m) so spaced out like you can see.

 

If the ship was moving slower, like 10m/s, the 5 particles would be spaced out over 10m, (a particle every 2m) and so it would appear to have more smoke.

The RAPIER engines on the ship is a lot clearer than Wheelsey exhaust, however, the point is the same. This doesn't effect actual gameplay in any way, nor reflects the status of the engines (except if there is no exhaust, which tends to imply no thrust ).

[Claw]

Krakensbane also had an interesting effect that when going fast enough, the exhaust smoke would actually "wrap around" such that the back end of the smoke trail would end up in front of the craft.