Trebuchet effect

I'm composing a piece for symphony orchestra, and I need a sound effect to resemble a trebuchet/catapult firing at a castle. I need it to be short and percussionistic (but might include other instruments than percussion too.) Any ideas on how I can do that?

I have a feeling you should start off with a reverse cymbal. The release part of the trebuchet firing could be involved with some strings. And whenever the projectile is flying, you could have a descending passage of woodwinds.

Maybe a massive tutti pizzicato chord? I'm not quite sure what I'd want from that, but definitely at least double or triple stops in the lower strings. Since its pizz, you could go crazy.

I forget the name of the percussion instrument that you wind...shoot. Perhaps look it up (dangit...its in Shooting Stars by Frank Ticheli, the first movement of Symphony II, if anyone is a band nerd) and contemplate that?

Just my thoughts.