I have seen this Comp ARF Mig 29 flying at Jetpower on a one engine installation. You can see that the smoke is from one side only. They use the second side for a parachute. I seem to re all this was a quite low power installation. The single engine installation is much quieter and needs less power.

John

https://m.youtube.com/watch?v=V6Qxg87FLOo