afaik the flames of that kind of turbo, if fully warmed up, should be more blue, they dont had a afterburner.
Only blue flames are economically effective and a little to fast throttle movement already did let flame out this early turbos.
yellow flames = soot = failsure.
1st engined flight by Richard Pearse, Waitohi, New Zealand, March 31, 1902. Karl Jatho, 1st flight, 18.August 1903, Hannover-Vahrenheide, real controlled flights.
The Wrights, 1st flight, 17. December 1903. They wasnt the 1st, but still claim this!