- #1
teamtom
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I built a catapult (trebuchet actually) last year for the "Punkin Chunkin" where you throw pumpkins for max distance. This year I am planning on a slightly larger one and need some advice on aluminum. We basically use a primitve crane idea to lift the weight up rather than using a hoist or whatever. See attached pic. By cranking up the cable, the beam which is hinged on the bottom slowly rises and brings the weight up with it, at the top, we secure the weight and crank down the beam. I used a salt-treated 4x4 last time and it was maxxed out with about 600 lbs. I was looking for a person or place to tell me what load I can use for a particular aluminum beam and a particular length lifting a weight. I can just start buying beams and trying it, but trial -and -error can get expensive at $300+ a beam.
I want to use a 18 foot long aluminum american standard beam 4"x.326. The load basically is pulling at a slight angle as shown in the pic, and I can provide a little more info, but I'm unsure of where to ask, or the equations I use to figure it out.
Any help would be appreciated,
Tom
I want to use a 18 foot long aluminum american standard beam 4"x.326. The load basically is pulling at a slight angle as shown in the pic, and I can provide a little more info, but I'm unsure of where to ask, or the equations I use to figure it out.
Any help would be appreciated,
Tom