Yo everyone! I'm back, and I made this for you as well, enjoy. Nautilus Particle Annihilation Engine sound from the anime series Nadia - The Secret of Blue Water. Approximately a 1.45 second loop from episode 11, part of the longest engine sound-only that I am aware of. Cleanest sounding version (and probably the only one that will ever exist) with no clicks, or pops in audio.
Nadia - The Secret of Blue Water (1990) and all related properties were "created" and are owned by Hideaki Anno and Gainax. Image source is screenshot and stitched from the exact moment of the sound and engine being presented.