Mysterious indeed. I have tried out both the Tribe and Nomads on the same map, and both do in fact behave differently: The Nomad ships are propulsed by the white blocks, which themselves have the usual trailing “particle-specks” coming out of them, respectively. The Tribe don’t show the white blocks, but simply have no exhaust graphics at all, not even the particle-specks. So there’s always just the map background visible behind the thrusters with the Tribe.
I am indeed using 1.47. I’ve purchased the base pack from the Positech shop, while the expansions are courtesy of Stardock, but I assume that shouldn’t make a difference.
As for me, I do only own the Tribe and the Nomads, as for now.
How come there’s no white block where the Tribe exhaust flame should be? As for the scattering trail of particles which follow the exhaust flame, are those textures too, or rendered on the fly?
Curious and curiouser… %-\