[InfamousX241]

Does all the air coming in get directed into the flame tube? Or does most go in and some air is allowed to pass? Also, the shaft will have to go through the flame tube I presume, so I was thinking of suspending the flame tube by screwing the fuel injectors into it on both sides. Is this sufficient?

Edit: Answered most of my own questions

[Smurf208]

I would have to say all of it goes threw, you want all of your air going into the flame tube to either burn or go with the flow threw the back turbine blades??? I would have to say it depends on the engines design. I think theres room to play with, i hope theres not 1 way thats the right way, cause i designed a engine on just what i thought would be the best way, do as you think is best??? lol thats prolly not the best solution but your guess is prolly the best way to go cause your the one building it and you know the engine best? hope that helped??

[Beaker]

No, yes air is allowed to pass
Typically 20-30% of air is for combustion And 70-80% is for the dilution stage

Dilution stage is used to control the (TIT) turbine inlet temperature.
Airflow into the primary combustion zone must be slow enough to correctly burn fuel mixture and its velocity is down to just a few m/s.
To fast a primary zone kills combustion or worse pushes it towards the turbine and overheats.

Pass some air from the compressor over the top of your shaft tunnel and then into the combustion chamber as dilution air just to keep the temp down. Bearings must be able to cope with expansion of the shaft as it heats up.