This is the sound of a GPU (ground power unit, a generator for airplanes) that won't start. It's a large piece of equipment
recorded with ICD UX560
I …
This is the sound of a crj 200 APU (the engine in the back, which is not a jet engine, which makes power for the plane).
recorded with …
This is actually a treadmill, but it makes a great turbine or engine sound.
recorded with Sony ICD UX560