I personally did not like the sound of the default F7 sounds being used on the FL9, so I searched what kind of engine they had and made new sounds for the engine.
I put an EMD 567 in for all the notches, revving up and throttling down. They are not the best, I know. Also, I found a better source (That sounds the EXACT same) for all the throttling down sounds, as the ones I used don't blend very well.
Here is a video of what this sounds like. Still need to fix the engine start sound, most of the throttling down sounds, and need to figure out how to fix the notch 8 sounds. (By the way, can someone help with that? There's no audio file name for notch 8 anywhere there) The horn and bell sounds are directly from an FL9 in real life, so don't tell me it isn't prototypical.
https://www.youtube.com/watch?v=e7nX2NxLuaQ
(I can't get the youtube thing to work, it puts the bracket things with my link in the center as text, not the video)
Engine shutdown sound (forgot to include in first clip)
https://www.youtube.com/watch?v=VTwbXE-m8ys