A while back, I looked at some of "VoloundExpounds' " videos on YT. For one of his 2m long sling videos (1mm thick UHWMPE), I was just making some very vague approximations, but I calculated 94 m/s in the last 1/4 turn of his throw. This was assuming 1/4 rotation, and a 2m radius, but it was 2*pi*(2m) * (0.25) for the distance traveled, and it did it in 8 frames, at 240 fps. So, 3.14m/ (.033s) = 94 m/s. This was an approximation, but damn that's fast. His release angle was not optimal, but if it could become moreso, and the wobble in the projectile wasn't that bad, it could go VERY far.
Here's a fun calculator to play with, the final distance is very sensitive to the drag coefficients (as one would expect).
https://www.desmos.com/calculator/on4xzwtdwzSo to get an idea of how far a throw at that speed could travel, I took my best throw as an example. It was 220m with a 30" sling, and probably an 80g stone,(maybe up to 100g...I wish I would have weighed it). Using that as a benchmark, and my fastest sling speed with a tennis ball (55m/s) I was able to arrive at the drag coefficients that allowed that sort of distance at a 35° release angle (Cd = 0.07, A=0.01, m=0.1). That gives 290m without drag, and 220m with drag.
Using the same drag parameters, if you move the release velocity up to 94 m/s, without drag, it can go ~850m, but with drag, it goes ~450m. These are approximate, obviously, since drag forces are VERY sensitive, but it gives you an idea of what's possible.
It makes me think that Larry Bray's throw (437m with a 50g stone) must've been 90+ m/s, I'd think.
And as a bonus here are some drag coefficients of normal objects.
https://www.grc.nasa.gov/www/k-12/airplane/shaped.htmlAnd how drag on a sphere is affected by speed through a fluid (air).
https://www.grc.nasa.gov/www/k-12/airplane/dragsphere.html