Thanks for the feedback guys.
I have had to make some changes to the files. A screw-up on my part was preventing more than one effect type from being used at any one time.
The link above and at CombatAce will give you the latest version, the readme should say
Version 2A in the top line.
I have also tweaked the engine fire effect. No flame and a darker grey smoke.
The engine fire and fuel fires can be rare depending on aircraft type. I suggest setting up a 12 SPAD v 6 Gotha mission and watching the fireworks.
Gotha goes down with fuel fires in both engines and airframe alight.
SPAD's getting chopped up by Gotha gunners. At least two fuel fires, several airframe fires and some general aircraft damage in-shot.