Hi Brian.

The smoke effects are normally located using the [smokesystem] commands in the aircraft.cfg file. The auto-generated contrails are located by adjusting the engine positions in the [GeneralEngineData] section. All of the afterburner effects I've seen have been located by commands in the [lights] section!

Now here's where the fun starts.

The positions of the effects in virtual FS space are located using three coordinates for vertical, lateral and horozontal position from the plane's datum position. These positions are unfortunately in a different order for the different .cfg file sections!

[GeneralEngineData] - the three coordinates are listed in vertical/lateral/horizontal order.
[lights] - longitudinal/lateral/vertical
[smokesystem] - vertical/horizontal/lateral

Also, in FS2002, changing the vertical parameter in the [smokesystem] section has no effect - it's a bug. So here you would need to start changing parameters in teh effects file itself. The Effects SDK tells you how to do this.

So you see how confusing it can be. To help accurate placement of the effect, you can substitute the name of a light effect (e.g. a beacon) so you can more easily see the location you are changing.

Good luck!

The tip provided by Micro above helped tremendously, now my aircraft has it's exhaust contrails properly positioned!  Many thanks for your help again.

Brian