I designed this simple trebuchet as a more stable, robust small trebuchet. The two opposite side frames are braced against each other so it doesn't need guy lines, which is the main problem with the older trebuchet design on Ropes and Poles. The Troop Scouters of the recent Gauteng Scout Wood Badge course at Arrowe Park tested it out and verified that it works (two of the patrols promptly ganged up on the third to send a shower of over-ripe tomatoes across to them). The theme of the Wood Badge weekend was 'the Knights of Gauteng' so this is the Knight's Trebuchet.
1. Build one 'A frame'- make sure there is enough space at the top for the throwing arm to rest.
2. Tie the base lashings of the second (yellow) 'A frame'/triangle and attach it to the first A frame
3. Lash the top of the yellow A-frame, making sure the crossing lines up with the green A-frame
4. Lash the two base poles on to the two frames.
5. Attach the throwing arm, which is lashed onto it's axle. Rest the axle in the forks on the top of the a frames, and 'mouse' the top of the fork to prevent the arm jumping out.
This trebuchet was tested with and without a sling.
The SketchUp model is available for download HERE.