Siege Punkin Chunk 2005: Mista Ballista's Story

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Punkin Chunk 2005: Mista Ballista's Story
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This was not Mista Ballista's worst year, but it wasn't one of our best either. The entire crew of Team Tormentum worked very hard all weekend to eek out a possible victory with all of Mista Ballista's new equipment.

Mista Ballista left Massachusetts around 10pm on Wednesday night after getting air in all it's tires, and drove right onto the chunkin' field on Thursday morning as setup began.


Mr. B early on Thursday, the scapus has been raised slightly to allow for proper deployment of the rope bundles. You can see here that the rope is now white instead of yellow. Our new weapon of 1" nylon rope was deployed this fall and required several changes to allow it.

Also new this year, our special Auxiliary Trailer. Our generator and hydraulic setup both hang out the back for easy use with a large rust-colored job-box full of tools in the front. Last year we hauled the pump and generator all over the field and into trucks for transport. This year we lifted those big items only once into the trailer, and once out again at home. As vehicles are not allowed in the pit areas, this short trailer was a perfect fit for our purposes, and kept the Pit Boss happy.

Jeff pulls out a new lever chain hoist for rope-bundle tipping. This greatly simplified the heavy-lifting (and kinda scary) erection of the rope bundles.

A view of the assembly process from on top of what we called "The Tiki Hut". You can see here that Chucky II arrived bright and early as well. Roger and Dave are assembling the dyno-frame on the back of the machine.

Members of Team Chucky came to assist as we put the on the long transverse regulae.

After welding on 500 lbs of extra steel gussets, a test lift was in order. This served two purposes. The first was to see if our old lift mechanism was still going to do the job, and the second was to perform some angle measurements.

To exceed our previous years angle, we had to dig a hole for the winch mount to sink into. Earlier changes to the trailer moved one cross brace to allow a greater angle. We were able to exceed our previous top-angle of 26 degrees with a new maximum of 39 degrees.


On Friday, we missed our opportunity to shoot a pumpkin, and instead spent the day getting our arms into the bundles, and the rope torsioned up. It took much longer than expected to get all the winding done. Our new winding chains, however, helped the process along.

Our first challenge was just getting the arm to slip between the two halves of the rope bundle. The new nylon rope, and the pre-tension we put on it made this quite a challenge.

Roger hooks the hydraulics up to the torsioning arm to begin the long twisting process. Dave looks on. Winding takes a minimum of two, but ideally 3 people. One to manage bolting the torsion arm down, and pinning the modiolus into place between strokes. A second person does the lifting and moving of parts. A third stands by the noisy hydraulic pump, and pushes control levers based on hand signals.

Here Jeff has unhooked a hydraulic ram from the massive new torsioning chain we use. This lets us get several strokes from the cylinder without moving or requiring precise alignment of the big torsioning arm with the end of the hydraulic ram.

After a full round of twisting, a test-pullback was made to settle the rope, and check on pullback pressure. The goal was to get very close, but not exceed, last years maximum pullback of 3600lbs.

At the end of the day, we noticed that one of the arms had gotten slightly twisted in the rope bundle. We tried to untwist it using levers and the chain hoist, but to no avail. The nylon held on to it too tightly. Eventually, we just unwound the top of the right bundle, pushed the arm into place, and retightened the whole thing.


Saturday morning we arrived bright and early. Roger applied some "torsion juice", and the winch hole was expanded. Here Dave checks the lift angle as we attempt to reach the elusive 40 degree mark. You can also see how the scapus is bumping into the trailer's cross brace. Since the ballista is hinged on the front of the dump frame, the frame can keep rising, and the scapus slides over this rail, and into the winch hole.

A majestic sight on a Saturday morning as we pull back for our first competition shot of the weekend. All the torsion teams were rooting for Mr. B to finally get off a great shot.

Ouch! Dave was sure that we hadn't exceeded last years pullback pressure, but none-the-less, our fancy composite, armor plated, unbreakable arms just couldn't handle the amazing power of our new nylon torsion springs.

What you cannot see here is that we also broke the arm on the left. Once freed by the bending of the right arm, the left arm swung forward, and hit the stanchion so hard, it folded forward and was rendered useless.

Thankfully, the hardwire material we used (see above link) didn't break, and only buckled, so no-one was showered with deadly glass shards. I know several chunkers caught this on video, and in great digital pictures. Email me if you've got something spiff I can add here.

Extra-large close-up of the damaged section.

You can see where the wood-core ends just outside the rope bundle (the fiberglass and resin is partially transparent.) Another foot out is the bend, and then the rest of the arm. Bits of hard-wire are all twisted up inside, but none of them broke. Amazing!

As we disassembled the machine, we checked the dyno. It turns out we had exceeded last years tension by about 200 lbs. It is amazing we came so close to blowing the arms last year without even knowing it.

We packed up the ballista on Saturday afternoon, and for our competition shot, I just got up there and threw a pumpkin as far as I could off the top of the machine. 22ft! Huzzah!

(If anyone [ aka, that guy with the video camera in the background of this picture] has a better picture than this I could use, please let me know.)

Here is an animation of the arms breaking. All 10 frames occurred in sequence, totaling 1/3rd of a second for the entire sequence. Also notice that no-one in the scene moves. During this timespan, we had no idea what was going on, it was way too fast.

Mouse Step Animator: Press Play or drag the Slider to switch frames.

01 02 03 04 05 06 07 08 09 10

From frame 1 to 2, notice that the base of the right arm moves from being attached, to be in the "at rest" position in the bundle.

In frame 6 to 7, notice that the left arm begins bending forward. In those frames, the second arm breaks in the opposite direction.


Google Video Service
Mista Ballista's arm breaks

During the 2005 Punkin chunk Mista Ballista breaks its arm on the first shot.
35 sec - Jun 25, 2006

Additional Pages for Punkin Chunk 2005
Punkin Chunk 2005 Team Tormentum returns to the World Championship Punkin Chunk for 2005 with our two machines, Mista Ballista, and the Pumpkin Putter. Both put on a pretty good show, though in two very different ways.
Punkin Chunk 2005: Mista Ballista's Story This was not Mista Ballista's worst year, but it wasn't one of our best either. The entire crew of Team Tormentum worked very hard all weekend to eek out a possible victory with all of Mista Ballista's new equipment.
Punkin Chunk 2005: Torsion Division The Torsion Division was really rocking this year, with old favorites, and a very competitive rookie.
Punkin Chunk 2005: Pumpkin Putter's Story The Pumpkin Putter returned into the Human Powered centripetal division and Kevin and Eric were eager to try out the changes we made this fall.
Punkin Chunk 2005: Human Powered Centripetal Division The Pumpkin Putter was up against our old foes from Pennsylvania this year. Despite their smiling faces, they had a goal in mind, and that goal was to defeat the Pumpkin Putter.

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