Building a trebuchet

This is a small portable trebuchet. The design brief was to be crude, unrealistic, and to fold up small enough to fit into my car. The beam is 2m long and the frame dismantles into 3 pieces, each 54" long.

The counterweight is a steel cage, filled with a dozen bricks. This is a partial test with 9, after the first assembly of the frame.

Ready for a test swing

Trebuchets shouldn't really be tested in small yards

Swing low, sweet trebuchet

Despite the obvious temptation, don't test-swing the weights before you've welded the cage together.

Crash !


I told you construction was crude. Steel tube pins hold the frames together.

Construction with steel tube pins

After some bending problems, we're going for 3/4" solid on the main axle.

First loading with all 12 bricks

The first test load (static !), with the full counterweight of a dozen bricks.


2nd July 2000

First firing !

26th June 2000

After a weekend of building, there's a swinging arm with weights on it. We need to build the sling, sling hook, projectile launch tray and release mechanism. The beam also needs tapering towards the hook, to lighten the rotational inertia.

So far this is our biggest trebuchet, but we're already planning the next...