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Spartan6
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My daughter and I built this for her science experiment on kinetic energy. We've fired golf balls, ping-pong balls and tennis balls with golf balls yielding the best result as to distance.

 

I copied the design from some pictures I found on the internet. Sorry all you college-boy engineers, I didn't do a single calculation except adding and subtracting some measurements. Oh and I did divide once. :lol:

 

I just looked at the pictures and made some scientific wild-a$$ed guesses about a few things and it works like a charm. ::):

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Thanks guys. ::):

 

Since we're "yard" testing this thing we've only used ten pounds of weight but I have no doubt you could probably go twenty or twenty-five pounds or maybe more without risking damage to trebuchet itself. With ten pounds of weight we've flung golf balls 37 feet and tennis balls about 30 feet.

 

So far we haven't broken any windows or even dented any siding. *Fingers crossed*

 

As far as accuracy goes we can't really "tune" the trebuchet because the weight is strung onto the bottom and it's kind of a pain to change. If you really sat and played with it and barring any environmental stuff you could probably put successive shots in a space the size of a hula hoop ( yeah, I definitely have kids) fairly reliably. Bear in mind this was originally designed to hit something the size of a castle. :lol:

 

Schweet! I've been wanting to make one just for poops and giggles for some time now. That and a catapult. Very cool. How does it fare for stability when you fire it since the frame is PVC piping?

 

It doesn't jump around at all since all the motion of it is pretty smooth and not jerky. If you really wanted to be all "Army" about it you could stake it down with tent stakes or something. ::):

 

 

I have some plans in a book for a tennis ball mortar that uses lighter fluid as a propellant... That may be next. :devil:

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Dude! I've seen a potato-mortar before! It used black rifle powder but whooo it was cool.

 

Oh... kids..don't try that at home. Blowy-uppy things can be really really hurtsy if they blow up at the wrong time or in the wrong place.

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I have some plans in a book for a tennis ball mortar that uses lighter fluid as a propellant... That may be next. :devil:

My high school physics teacher showed us how to make one of those. Loads of fun, especially when we almost caught my friend's dog on fire. We doused the tennis ball in lighter fluid as well as using it as the propellant so they would be flaminig tennis balls flying across his back yard. The dog wandered just a little too close to one of them, but wasn't hit. For the record, we weren't trying to hit the dog. On the other hand, if it had been a cat......

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If you really wanted to be all "Army" about it you could stake it down with tent stakes or something. ::):

 

Pretty sure that a Trebuchet isn't hindered by being staked down, but IIRC catapult/onager designs do better when on wheels. Helps their accuracy and helps avoid wear & tear on the structure.

 

Great stuff Spartan!

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We built a trebuchet in cub scouts. ::D:

 

it's weight was a 1'x1'x1' box full of gravel. I have no idea how heavy it was, but once we got it tuned right, it threw tennis balls in excess of 150 yards. It was kind of scary to use, because when the weight came back down after firing, it would rock back and forth and threaten to brain us innocent youngsters.

 

Those things are a ton of fun, wish I could come over and play with it ::): .

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A Scout troop I was once a member of built a seven or eight foot tall trebuchet, launched some tennis balls. It was cool, especially since all they used was rope and logs--they did it the "real way" ::D:

 

My cousins made a potato-gun. Used hairspray for propellant, I think. Could shoot a good 50 yards--we'd shoot them into the lake :lol:

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One year at a tri-district camp one of the competitions was building a trebuchet or catapult out of wood and rope. You had to launch nerf footballs. Whoever launched it the farthest won, I think. My scout troup (canadian, so girls are allowed in, thank goodness, the local girl guides main raison d'etre by this time was shopping) built a catapult. I believe we did alright. ( I was in the teams for the other games)

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Based on the size and length of your swing arm, I wouldn't go over more then ten pounds, you'll need to start doing some changes to the sling holding your projectile.

 

I'll let you guys know when we get the 10 foot swing arm treb built she's gona be fuuuunnnn

 

Mad Pat

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With a few of these we could all dress as our favorite mini and have some live-action Warlord. :devil:

 

We doused the tennis ball in lighter fluid as well as using it as the propellant so they would be flaminig tennis balls flying across his back yard.

Sounds like something I would have done. ::D:

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