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Workbench Creations

Workbench Creations is the place for conversation and discussion about do-it-yourself (DIY) projects. This DIY blog will feature projects completed by its owner as well as projects completed by other do-it-yourselfers. Workbench Creations is the place where DIYers can discuss ideas, learn about what others have done, and share their expertise.

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Pumpkin Chuckin’ With CR4

Posted October 29, 2008 12:00 AM by Sharkles

This past Friday, a few CR4 bloggers wanted to get into the spirit of Halloween by launching pumpkins. While "pumpkin chuckin'" is a pretty popular around this time of year, we decided to put our own twist on it by using frankd20's drywall catapult as a trebuchet.

Ready. Aim. Fire!
We began testing the trebuchet by launching water balloons. Unfortunately, the first run didn't go as well as we'd hoped. Despite the high levels of excitement from the crowd, the trebuchet repeatedly collapsed – even leaving a couple of water balloons and a pumpkin relatively unharmed.

Ultimately, after multiple attempts, it was concluded that the first run at firing the trebuchet was a failure due to lack of research. The original device was built to lift dry wall, not to be a firing device. Only an hour or so was spent doing the conversion from a lift mechanism to trebuchet, which mostly consisted of making the firing release mechanism.

When the crowd had started to assemble that day, we weren't even completely sure the trebuchet would launch anything. With each collapse, we lost a few audience members. The problem with the trebuchet was that it wouldn't let go of the pumpkin at the apex of the swing. Time after time, the machine would hold on to its projectile and not fire anything.

See videos of the first attempts here.

Back to the Drawing Board
Despite not having success, we were all pretty entertained with the attempted launches and eventually returned to work as usual. However, after just 15 minutes or so, frankd20 figured out the problem and did a quick fix so that another round of launching could take place.

He determined that the solution was to add a mechanism for the sling to let go at the apex. This consisted of a metal spike sticking out of the end of the main beam that one side of the sling, tied into a loop, is loosely hooked over. As the beam pulls the projectile, it stays hooked until the projectile is pulled around by centripetal force and is in line with the beam. About the time the main beam and sling are perpendicular to the ground, it will release. The centripetal force of the sling pulls the loop off of the main beam, which releases one side of the sling and let's go of the projectile.

Once the fix was made, the fun began. The second pumpkin of the day sailed through the sky and landed with a satisfying thwack, breaking into pieces. We also experimented with a rotten apple and a small stuffed animal dubbed "Sir Launch-A-Lot" – both of which flew successfully. The final launch of the day sent a pumpkin soaring; and as the crowd went wild, the pumpkin ended its flight with a flurry of seeds and debris. Overall the experiment was a success; only Sir Launch-A-Lot survived (because he's stuffed) and the rest was smashed into deer food.

See videos of the successful launch here.


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Join Date: Feb 2005
Location: New York
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Re: Pumpkin Chuckin’ With CR4

10/28/2008 4:27 PM

Everyone had a great time at the trebuchet launch.

Special thanks to frankd20 for making it all happen.
When will you have trebuchet version 2.0 ready??

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Re: Pumpkin Chuckin’ With CR4

10/29/2008 12:04 PM

I used to live in Colorado Springs, and on the west city limit is the town of Manitou Springs. They sponsor a New Year's event called the "Fruitcake Toss". Originally, launching was by arm strength, but in recent years, trebuchets, onagers, catapults, giant slingshots, and even compressed air cannons have taken center stage. Now, awards are given in several classes. And, let's face it, what else ya gonna' do with that fruitcake Aunt Nellie gave ya for Xmas?

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Re: Pumpkin Chuckin’ With CR4

10/29/2008 1:45 PM

Chucking pumpkins was quite entertaining, even the failed attempts. All in all, I'd call it a smashing success! Kudos for the conversion of a dry-waller to a trebuchet 8^)

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