from the whip-it-good! dept.
The trebuchet is a type of catapult that was popular for use as a siege engine before gunpowder became a thing. Trebuchets use a long arm to throw projectiles farther than traditional catapults. The focus has typically been on increasing throwing distance for the size of the projectile, or vice versa. But of course you're here to read about the other thing that trebuchets can be used for: speed.
How fast is fast? How about a whip-cracking, sonic-booming speed in excess of 450 meters [~1480 feet] per second! How'd he do it? Mostly wood and rubber [bands] with some metal bits thrown in for safety's sake. [David]'s video explains in full all of the engineering that went into his trebuchet, and it's a lot less than you'd think. There's a very satisfying montage of full power trebuchet launches that make it audibly clear that the projectile being thrown is going well past the speed of sound, with a report quite similar to that of a small rifle.
Link to 15m45s YouTube video with demo near the end.