Hello,
Well, I chose this set up because it is easy to install and most of all, it keeps the oily mess away from the pipe and the fuselage !!
Besides, I guess that the real display jets do it as well in this exact way.(at least the F5 Tigers of our Swiss Team)
It might be a little bit less effective compared to a direct injection right after the turbine exaust.
But on Firebird, I have a wonderful ducting system for the AMT Netherlands Olympus and this motor is filling the thrust tube with a lot of hot gas !
I run that motor at up to 112000 RPM which is the max allowed and nevertheless reaching a moderate max EGT of around 670 degrees Celsius.Well within limits !
Again here, the perfect ducting is helping definitely to keep the turbine running cool even at very high thrust settings !
The Harris smoke pump is probably not the one delivering the highest flow and I might consider a change here in the future to a Deutsch or Emcotech which promise
flows of up to 1 Liter/min
see you
Hans