Originally Posted by rich smith
Another has nothing behind the prop and bigger space in front of and around the slot (like Jacko). It is almost dead silent and runs on 6 clicks. A couple in-between configs perform as expected.
Noise requires energy which is robbed from the prop. I also found this to be true for a full size pusher ultralight aircraft I fly which makes a lot of noise when the prop is nearer the TE and requires noticeably more throttle.
Any vibration or noise from things like unbalanced engine/redrive or badly tracked props take away from thrust. More than you might think.
Any pics of your "quiet" slot Rich?