Catapult

glennbad

glennbad

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Hey Gang,

Not sure if this should be in gadgets and gear, but I thought I'd try here.

As a cub scout den leader, one of our requirements is for the boys to build a catapult. Now, what boy doesn't like to launch things through the air???

They can build small ones themselves, but in addition to that, another den has thrown down the gauntlet and challenged us to make a bigger one. I have plans for a trebuchet, but I am looking for plans for a catapult. Hopefully, around the size that one adult could carry by themself.

I've spent the morning scouring the net, but the plans I have found are either too big or cost money...

Any help you could give would be appreciated.

Remember, a scout is never truly happy unless he is launching a rock, small pumpkin, or the family cat through the air...

Thanks,
Glenn
 
When I was an Assistant Scoutmaster, I was at a Camporee where we were allowed to cut down the trees as they were planning to develope the land anyway. One of the troops decided to build a water balloon launching trebuchet out of the trees using Scout power for the launch. It worked quite well and was a great hit in both senses of the word.
 
glennbad said:
Not sure if this should be in gadgets and gear, but I thought I'd try here.
Click to expand...

Yes, it qualifies as G&G material.
 
I did find some plans for a tennis ball trebuchet:

http://www.ripcord.ws/plans/plans.html

What kind of catapult were you considering? Onager? Mangonel?

If you're thinking about throwing a small pumpkin, the moment arm length would be considerable, as would the counterweight.

You might want to checkout the Pumpkin Chuckin' competitions. It probably would give you an idea of scale.
 
Actually, I was leaning toward the Mangonel design in a catapult. I was only kidding about the small pumpkin launching, nothing that big...

I did find that trebuchet plan as well, and may try that for variety.

Thanks for digging...

The search goes on...

Glenn
 
Do you want to build a more powerful seige engine than the other den, or a more accurate one?

A trebucket is great for accuracy; they're very consistent so you just walk it in on your target and then you can keep hitting all day. It would have to be very large to have a lot of power and range.

A catapult -- I mean a real catapult, powered by twisting a rope -- is not as consistent; the springiness of the rope varies with temperature and humidity -- but you can get a lot of power in a small package.

Irrelevant Story
When I was a Cub Scout we had a father-and-son project -- we were given a list of materials we were allowed to use, and we could build anything we wanted. My father and I decided to build a kind of catapult, using the springiness of a coathanger to throw corks. We found out a coathanger (mild steel) is not really very springy, so it wasn't very powerful -- but it was fun anyway. It did throw corks, just not very far.
 
If you want to see some impressive machines, check the "gallery" section of the World Championship Punkin Chunkin Association web site:

http://www.punkinchunkin.com/main.htm

The air cannons lob a pumpkin over 4200 feet. The catapults 2100, trebuchet's 1400, and the onager 1500.
 
My daughter and her group built a very simple one some years ago, it was made mostly from 8 feet long by 1 1/2 inch diameter poles, a basket and cord, I never saw them shoot it but they beat everyone else shooting water balloons, I have tried to make a drawing from my daughters description.

To fire lower the basket, put in the ammunition, a couple of girls grab on the handle opposite the basket and at the count of three, pull down hard and let go.

Luis

e9t945.jpg
 
Last night the boys and I made some very simple ones that shoot mini marshmallows. They had a blast, and have the fever now I think. I found plans for a small tabletop model. I think we will make these next week. I'll post a pic of our results...

Thanks everyone...

Glenn
 
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