I just can't resist...
Any story that mentions "consulted two mechanical engineers who said it wouldn't work, but tried it anyways" has GOT to be a good one.
On one page:
Hm, isnt the trebuchet the design with the projectile in a sling though?
Yep. I actually think he built a catapult.
I thought trebuchet meant the counter weight design (as opposed to flexing a wooden beam etc.), rather that how the projectile was held.
Ah, fond memories of Simpsons episode 4F15 ( http://www.snpp.com/episodes/4F15 ).
A trebuchet is gravity-powered, whereas a catapult is spring-powered. In practical terms, this means counterweights for the former, and something that is flexed for the latter. Having a sling vs. a platform on the end of the throwing arm is just the launch method, and doesn't restrict/depend on the propulsion method.
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