There is likely data out there somewhere on AH-56 signatures. My curiosity is as to how much aural signature is generated when you shift the prop into beta (reverse thrust). It came to be listening to a C-130J doing a short field landing demonstration. There was a very noticeable signature from the props when they did so. Sikorsky is pitching that it is a quiet helicopter so I am wondering, how far out do you have to turn off the prop to make it quiet(er)?