As to the poster's original question. First off I want to state up fron that I do not operate RC turbines. However I am an A&P and have worked on Jet engines 22+ years.

1. The spool up time is controlled by either the ECI or FADEC unit. In essence what the computer does is to ensure the engine does not go into a "Lean" state and thus give you a Hot Start or hung start condition where the engine is running but is not at self sustaining speed and will not respond to throttle control,

2. This ensures the engine doesnot cook itself to death.

3. If allcomponents are working correctly the combuster depending on air flow will allow the engineto spool up while preventing flame out.. It is commonon corporate jets as well as the airliners to hear a popping orgurgle/surging as the engine spools up.

4. on a pure jet type design(non by-pass) engine suchas the military fighters of old, I will give as an example the J-79 (F4 phantom engine) when they first hit the frontlines they had spool up problems and the fix was touptrim the fuel control (Increase idle RPM) where the engine would transitionmore quickly.

5. As the previous postshave mentioned airflow once airborne will helpthe transition time due to ram air effect.

6. Thedown fall up an uptrim isthat the increased thrustcan have an effect on landing distance.

I have not watched the videoand I am just giving you some generalinfo. The others who have first hand knowledge I would listen to. I hope I have not confused you. However a turbineis a turbine is a turbine.

Regards
Glenn Williams
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