2 OF's need plans - Graybeard Outdoors
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post #1 of 53 (permalink) Old 02-25-2017, 09:14 PM Thread Starter
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Default 2 OF's need plans

Two old guys with to much time on their hands looking for a project, so we decided to build a Bowling ball trebuchet. Anybody have any idea where we can find some plans?
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post #2 of 53 (permalink) Old 02-25-2017, 09:35 PM
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Found this on Google: http://www.instructables.com/id/How-...ome-Trebuchet/

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post #3 of 53 (permalink) Old 02-25-2017, 10:07 PM
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My son gave me a small kit for Christmas, it was from Amazon. You could maybe get one and scale it up. This one shoots wood balls the size of marbles.
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post #4 of 53 (permalink) Old 02-26-2017, 01:04 AM
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Memory slipping Douglas. I would think you OFs would remember these first hand being used back in the day

So I assume this is a catapult you want to make? Freds looks more like a Mortar? So am unsure what you are thinking ..Look interesting for sure though, and probably alot of fun.
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post #5 of 53 (permalink) Old 02-26-2017, 03:20 AM
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there was a program on TV where one group made a Trebouchet, and one made a catapult

the catapult was AMAZING! it would easily out shoot a Trebouchet by twice the distance.

I would think for launching HUGE weight (like 2000lb) a Trebouchet would be more effective, as it would be easier to upscale and still work.

but for bowling ball size and smaller, that catapult was incredible. it shot AMAZINGLY flat.

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post #6 of 53 (permalink) Old 02-26-2017, 03:46 AM
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A trebuchet is a counterweighted lever while a catapult is a torsion spring powered lever. Large trebuchets can launch much heavier projectiles to much greater distance than a catapult. Here is a youtube of a big one in the UK:
At one time I thought about making a 10 footer and did some calculations for one but never followed through. There is, however, at least one website that has the calculations set up as a parameter list: Virtual Trebuchet. However the one that impressed me most was The Algorithmic Beauty of the Trebuchet.

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post #7 of 53 (permalink) Old 02-26-2017, 10:27 AM Thread Starter
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Well x-49 your link was interesting and it lead me to http://www.stormthecastle.com/trebuc...et-physics.htm which had some really interesting numbers. Ratio of weight of ballast to projectile, 133:1. So to lob our 16 lb bowling ball we a 2128 lb counter weight. Wow. Wonder if our eyes are bigger than our stomach.

There 10 foot Trebuchet would probable work just fine with the 6 PDR Zinc ball I shoot from the "junk yard dog". It looked interesting and might be a very doable project that we can get the Grand daughter involved in. Not to big.


Through various links in that webpage I found this one. A High school physics class project lobbing Golf balls.

That looks very interesting. Maybe more into our appetite. How they set uo to adjust the angle for the release pin is pretty clever.
George, the engineer for ever. At first I was a bit over whelmed by your links especially the Algorithmic link, way way over my head, way over. But right in the middle of his website is the tickler-a bowling ball trebuchet. No links or details, just two pictures. That fellow will get an email.

Looking at bit more at the Virtual Trebuchet link and some things started to click and I can see we can probably use this link for predicting the ballistics of our Machine. Thanks George.

I will have to talk it over with my friend and see what he thinks. We are looking for just a project to keep two retired old guys busy. We both have wives who like to find things for us to do when they think we aren't doing anything.

Keep the ideas coming.
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post #8 of 53 (permalink) Old 02-26-2017, 11:09 AM
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My daughters built one with a 5' beam length and 20lb weight. It would throw eggs about 50'. The plans scale up from marshmallow throwers to old cars.
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post #9 of 53 (permalink) Old 02-26-2017, 05:13 PM
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Did you notice the "Hamster Wheel" on Georges pic ?

For a human to winch the arm down . Yea thats pretty big !

It must have been a real hoot to have seen that thing hurl a ball toward your own self..........?
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post #10 of 53 (permalink) Old 02-26-2017, 06:11 PM
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