Originally posted by Sushi mk. 2:
Aaaah... That I did NOT know.
I bet that'll fix it!
Now for those pesky thruster flames... First person to figure it out gets a cookie! 
I think I know what is wrong. First I am going to assume that your thrusters are multiple triangles in length:
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sorry for the pathetic ascii art, but anyway what I think the problem is is that FS2 can't handle thruster flames like the one I 'drew'. It needs to be 1 segment, or just a point. That is my theory, and if I just shoved my foot in my mouth because it works for other ships, I'm sorry

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-Analazon
Creator of the mod that will not be coming for a while