Too much time on my hands?

A traction trebuchet is not the giant, dead-horse-flinging, counterbalance-powered siege engine you frequently see pictured. It's smaller and powered by humans hauling on ropes to whip a stone up and out of a sling. I saw a reproduction in action at a Medieval Congress years ago, and recently said, "I bet I could build a scale model of one of them." Judge for yourselves.

This is from the Maciejowski Bible, a 13th century source with lots of first-time-seen illustrations, including this somewhat obscure image of a traction trebuchet in action.

This is my 10-second sketch of what I thought I could quickly build with bass wood and left-over 25mm wargaming figures.

And this is the outcome. As built, it wouldn't work, or at least very well. The sling is too short and the boom is probably too short, as well. It would probably fall over forward, since it's insufficiently braced fore and aft. Plus three guys is a slim crew. But it was amusing to build. For extra credit, how was I able to work wine bottle foil into this piece?