Friday, December 01, 2006

Building A Catapult

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Today's St. Paul Pioneer Press contains an article about a blacksmith in Pepin, Wisconsin who built a trebuchet with the intention of hurling a fruitcake. The reporter gave me a call for background, and mentions my book, The Art of the Catapult in the story.

The thing is, the trebuchet in the story looks like it's been built with 2x4's and a fairly small diameter pivot rod. I've seen a lot people try to build catapults from softwoods and such, but they typically fall apart after a few hurls.

I get a lot of inquiries about building catapults large enough to throw pumpkins. That's a big order. An eight pound pumpkin needs an 800-pound counterweight and you can't easily do that with a catapult made from regular dimensional lumber. There are tremendous stresses on the machine, especially under rotation. This fellow seems to be successful with his fruitcakes though.

Building your own catapult is a great project. For those interested in building their own catapult, I recommend some of Ron Tom's catapult kits. I've built them and they work very well. His Scorpion kit uses a bungee cord and the design and performance is quite impressive.

For those who want to build their own models from scratch, pick up a copy of the Art of the Catapult.

1 comment:

Jered said...

My friends and I built a Catatpult at College for our pumkin Chunkin. WE used a 500 pound counterweight to catapult it 389 feet. WE built it out of standard sized lumber and it held together. After several throws, the main axle (1" solid steel) bent from the weight.