The Backyard Ogre Catapult

Today we’ll be setting aside the circuits and solder for a little while in favor of good old fashioned wood and bungee chords to make this backyard catapult. Items needed include nine sections of 2×3 wooden beams of varying lengths, some screws and eye hooks, a bungee chord, a broom handle, and a few other things which are all detailed in the read link below.

Here’s a quick summary version of the four pages of instructions: First the 2x3s must be cut to their proper lengths. The two 24-inch beams must then be drilled to create pivot holes. Notches should then be cut into them with a saw. The same should be done to two 14-inch beams, which will allow them to be fitted to the 24-inch beams at a right angle. With the two 7 1/2-inch beams, the six beams make up the base of the catapult and two support arms extending upward. Two more beams, a crossbar and angled beam, are added to complete the support system, leaving it prepped to add the swing arm.

The swing arm is a 28-inch beam with the broom handle running through a hole in the bottom and a cardboard cup at the top. The broom handle will also run through the pivot holes in the base. The bungee chord should be stretched from an eye hook on the swing arm and one on the base. The strength of the catapult can be adjusted by using a stronger bungee or adjusting the height of the crossbar. For slightly more complex mechanics, bearings can be added to the pivot points to ensure smooth and efficient energy transfer.

[via DIY Life]

28 thoughts on “The Backyard Ogre Catapult

  1. What is this? Like its just a catapult. Haha its just a basic design, not even a hack on a catapult design. Add a computer to control the catapult from your computer and measure the physics of the launch then you have a hack…but even that is worthless. When did hack a day stop being relevant?

  2. Why does everyone have to comment about something not being a hack? Yes, I know this is Hack a Day, but they have already provided 1 hack today. Everything that follows is just a bonus for our amusement. You people fail to see that we now have 3 to 6 posts in a day as apposed to the 1 post of before. More content is a good thing. If you don’t care for it, then just ignore it and move on.

  3. a box? did this guy seriously use road runner cartoons as his blueprints?

    real g’s use slings in their catapults, don’t even get me started on the linear bungee cord, he should have used torsion from several bungess.

    seige machines. it’s serious business.

  4. Have you guys not noticed that the black & white photos with the tape on the corners == hack?
    Everything else is just cool/interesting stuff, that is perhaps on topic with some other post/hack…

    Catapults are nice, but I personally prefer Trebuchets…

  5. agree with netdigger on the fact that a 10 year old could do it. And I believe it is onager, meaning wild ass, describing the “kick” that the machine gives. ogre is a mythical creature such as shrek.

  6. At this rate I’d might submit my trebuchet which is made only from various types of computer memory boards. That would be 1. a more effective design of siege engine and 2. more of a hack. Yes that item does infact exist, but I will not bother you with it really.

  7. Your encounter the teachers offer on the student has been invaluable. You might discover the item impossible to understand woodworking not having all the information in addition to expertise the fact that you will get from a woodworking teacher.

  8. What a great idea. I was looking for just such a simple design for a catapult to build with my five-year old son. We are having a party next weekend and need one so that the “kinder men” can launch rotten eggs down the hill in the back yard. Simple and quick for a busy mom to build – perfect. Thx

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