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World Championship Chunk 2006 - Mista Ballista
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Mista Ballista left it's mark on the Chunkin field with two throws over 600 feet, but getting there wasn't easy. Our first two days were plagued with bundle winding problems. On the bright side, we made it through the year without breaking the arms, or any other major throwing component of the machine. Huzzah!
Mista Ballista, testing our winch hole to see how far we can raise the engine in the air.
We start the tightening process using come-a-longs. They have a much longer throw than the hydraulic cylinders and speed things up some for the first few winds.
The next day, we added a quarter turn, and on the last bundle end, the torsioning arm let go. The pins on this arm fit into the pin holes of the modiolus. Our hydraulic tensioning system ripped this right off the machine, bending three 1" pins, and shearing a 1/2 inch grade 8 bolt. The bottom unwound so fast, it tightened itself in the opposite direction and prevented the arm from drooping.
Fortunately, we have two such torsioning arms. We investigated, and discovered that our backup had a loose pin! We were apparently mere moments from an unrecoverable failure here too. Dave repaired the backup arm, and added even more weld to it for good measure.
As we tightened that bundle back up to it's previous tension, the cause of the original problem became apparent. The torsion arms bolt into threaded holes on the modiolus. Two years ago when we made those holes, the epizygis was much longer, and there was a wide space where there were no holes. The arm had to be positioned sticking way out the side. The hydraulic system then pulled at an inconvenient angle, and this caused the failure. To solve the problem Dave pulled out his magnetic base drill press (sweet, huh?) and we bored and tapped new holes so we could tighten more effectively. This rescued us from not chunkin' at all this weekend.
Bolt on the new torsion arm with the new hole. It worked! Huzzah! A big thanks to Dave for his hard work and ingenuity.
At long last, Mr. B got to start chunkin stuff!
This is our third generation splicing style. Roger spent many hours on the phone with helpful folks from New England Ropes (who sold us the Vectran) attempting to devise the ultimate splice design for our use. Thanks New England Ropes! In addition, Amy knitted us a new sling. The more we shoot stuff, the smaller we discover our throwing pouch needs to be.
Putting the new system under tension. And check out the new signs Kevin made for us. Huzzah!
When the Association says "8 to 10 pound punkins" they mean it. Measuring our 8 lb 10oz pumpkin for our 3rd place 670 foot shot.
That's approximately 22700 foot pounds at the base of the arm, compared to 26800 foot pounds at the point where we had a catastrophic failure last year. To put in that tension, we had about 7000 lbs exerted by the hydraulic ram which was running around 800psi at the pump when the previous torsion arm broke.
Thanks Jim Goodwin for these two great pictures.
Team Tormentum worked hard all weekend and it paid off. Thanks guys!
An animation of Mr. B firing our 1st competition shot. These 16 frames represent about 1/2 a second of real time.
Google Video Service --
Mista Ballista First Shot 2006
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Contact: Team Tormentum Copyright © 2000-2022 Eric M. Ludlam All rights reserved. Twas' brillig, and the slithy toves did gyre and gimble in the wabe... | Last Modified: 05/10/09 |
First things first. Both modes of starting on our hydraulic pump failed. 
Hoist the long transverse regulae into place.
We then tightened the rope bundles late into the night. It takes a looooong time to get this
machine tightened up. At this point everyone was operating on about 2 hours of sleep from the past 2 days.
Loading a punkin into 
Sproing!
And with that, the 3rd place trophy was ours!
When Adam (of team Chucky) stands up on stage and says "TORSION RULES", he means it.
Chucky II of the torsion class out threw all other catapults on the field with an amazing throw of
over 2000 feet. Wow!
Various other pictures from the chunk.