This is beyond cool.
David Eade (an engineer or engineering student, I don’t know) produced a video about trying to build a supersonic trebuchet. Eight minutes of it (1:00-9:00) are engineering equations that will make your head swim, but he demonstrates how to design (and what materials to use) and build his trebuchet.
The frame is wood, the elastic is rubber, and the arm is titanium. He calculates that the projectile is fired at over 400 metres per second. That’s 1440 kilometres per hour, which is faster than the speed of sound. You can actually hear the sonic boom in some of his test fires.
And sorry to harp, this also demonstrates how to make videos, very pleasant to watch and easy on the brain.
Marcus Ranum says
Department of Defense spokespeople, speaking on and off the record (i.e.: on the record, not for attribution) have said that there are deep concerns regarding the “supersonic trebuchet gap” and Boeing is investigating partnering with Lockheed Martin to produce a hypersonic trebuchet. Meanwhile, Elon Musk has announced a new startup building trebuchets that will inexpensively launch his shareholders’ investments into Mars orbit. Jeff Bezos announced that his company will produce “low-earth orbit” trebuchets capable of launching wealthy people on safe but expensive joy-rides. Rumors are swirling that Kim Kardashian has agreed to be launched first, but only if Kanye is ballast.