How do you make a proper Trebuchet sling?

My group is doing a Trebuchet for Engineering class and we've built it and it's ready to go. But it's missing the sling. I've tried making a sling but I feel I've been doing it completely wrong. Because the projectile (wooden ball) would either hit flat on the ground or never release. I'm also confused as to how the sling works, I realize one end is tied to the arm and another is free floating and unhooks and releases the projectile, but how exactly should you do this? Is there any good tutorials that don't leave out details, or at least explain it a little better? Any help is greatly appreciated and will prevent us from failing.

IronFrobert8 years ago
Yeah, I built a model trebuchet in Aplied Design, but I can't figure out how to get the sling to release, if anyone has any close up photoes it would be appreciated.
put a key ring on the end of the 'free floating' side and on the lever arm put bent nail
Kiteman8 years ago
Once you have your sling, the secret to a good shot is the release angle - the fixed side of the sling is below the arm, the hooked side is above that.

Make the (folded) sling about a third of the length of the distance from pivot to hook, and then tweak the angle of the hook to adjust the final angle of release.

(I say "hook", but it should really be a short peg, bent upwards around 20-30o above the angle of the arm.)