I know I’m not the 1st to try it, but I’m playing around with the idea of placing whistles on a 3” rocket. I have 3 HyperWhistles, claimed to be the world’s loudest, reminding me again how much I loathe utterly unverifiable marketing claims, but decided to try them out. They are very loud, but I don’t think they’re near the 142db claimed. They’re 79mm overall length, about 36mm in diameter, and weigh 22g. My first idea was to place them on the tips of the fins, with the “blow hole” ahead of the leading edge, catching as much clear air as possible. After thinking about it for a bit, I visualized this configuration doing a long lazy arc in an unintended direction. In think at that distance from the thrust line there’s no way they’ll be balanced enough to fly straight. I may have attempted this on a B or C impulse scale, but I’ll be flying this on an H178, and believe the results could be catastrophic. Now I’m thinking about placing them aft and between the fins on the body. They should be close enough to the thrust centerline and balanced well enough to fly straight. Whether there’s enough air flow at the needed pressure to have any effect… I guess I’ll have to find out. What are your thoughts?