For many of us, our first encounter with the famous trebuchet was Age of Empires II, or perhaps a documentary on historical siege engines. However, many people continue to pursue builds of their very own, exploring designs new and old. The walking arm trebuchet is a good example, which uses an unconventional design to great effect.
The design eschews a rigid frame, instead consisting of simply an arm and a triangular leg assembly. The arm is held upside down, and is launched by allowing the trebuchet to collapse forward to rest on the triangular leg. The triangular leg is fitted with spikes which dig into the ground, and the arm then pivots around, launching the projectile. The design is reportedly quite efficient, similar to a floating arm trebuchet, with a very simple design. Performance was so good, it netted a clean sweep of the 2018 Vermont Pumpkin Chuckin’ festival.
There’s a wide variety of ways to go about building a trebuchet, and we’ve featured some before. You can even instrument your payloads to quantify performance. Video after the break.
Continue reading “Walking Arm Trebuchet Is Different, But Effective”
If your local surplus store is fresh out of supercapacitors but you’re just really in the mood to fire stuff at other stuff, check out [austiwawa]’s step-by-step guide to building a thermal cannon. It shoots whatever will fit into a 1/2″ copper pipe, propelled by cut-up matchheads and lit by a propane torch. [austiwawa] demonstrates it by firing an AA battery at an unsuspecting pumpkin. For what it’s worth, we don’t necessarily condone applying this much heat to alkaline cells.
[austiwawa] used a copper pipe for the barrel because it provides the fastest heat transfer. One end of it is flattened and folded over to form the propellant chamber. A couple of packs worth of match heads are tamped down into the folded end with a paper towel serving as wadding. [austiwawa] tosses in his battery, lights the torch, and then runs away.
This whole dangerous contraption is secured to a wooden base with a u-bolt and a couple of pipe straps, and suspended between more pieces of wood with a length of threaded rod for stability and aiming.
We’ll let the safety-conscious readers do our work for us in the comments, but in the meantime, note that this thing is not safe. As [austiwawa] demonstrates, the copper gets brittle and will split open along the folded edge.
But kudos anyway to [austiwawa] for showing shot after shot of the cannon in action at the end of his video. You know where to find it.
If it’s a stronger, more beautiful barrel you’re after, just machine one by hand.
Continue reading “DIY Matchhead Cannon Brings The Heat”