Mista Ballista is Team Tormentum's Torsion Division competition catapult.
We started construction in 2000 with our first purchase of two very large steel donuts
that now make up the lower scutulas.
The different pages documenting Mista Ballista focus on different aspects
of it's construction and do not go in chronological order.
2016 Extreme Chunk
Mista Ballista hits a new personal record 1232.9 ft.
2015 Extreme Chunk
Mista Ballista competes at the first anual Extreme Chunkin event in New Hampshire.
This was our first year with shorter arms and compounded bowstring.
Our long shot of the weekend was 1031 ft.
2013 Punkin Chunk
Mista Ballista shoots 1059 ft on Sunday after removing compounding used on the Friday and Saturday shots.
2012 Punkin Chunk
We break the 1200 ft mark, and try out compounding. Compounding was awesome, but needs some work.
2011 Punkin Chunk
A new throwing pouch, bowline separators, and pretensioning let us break the 1000ft mark with our pumpkin!
2010 Punkin Chunk
Getting stuck in the mud trying to get ready for the Punkin Chunk with newly pretensioned bundles.
2010 Building Demo Deployment
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Throwing projectiles at a building at a company expansion celebration in 2010 at the MathWorks.
2009 Punkin Chunk
New additions for this year include arms stops, and cribbing to raise Mr. B up off the ground so we don't need to dig a hole.
2008 Punkin Chunk
New additions for this year include aluminum arms, and a new set of Modiolii for adding torsion into the system.
Mr. B just before launch at the 2007 Punkin Chunk. This resulted in a 582ft chunk.
Mr. B getting ready to launch at the 2006 Punkin Chunk.
2800 lbs of measured tension is sitting at the trigger!
That's approximately 22700 foot pounds at the base of the arm, and perhaps 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.
| Sproing! 670 feet! |
Thanks to Jim Goodwin for these two great pictures.
| First competition launch at the 2005 Chunk! |
| Ouch! Things didn't go so well for us. |
2005 Punkin Chunk.
| Preparing for a test launch at the 2004 Chunk! |
| Sproing! |
2004 Punkin Chunk
| Preparing for a launch at the 2003 Chunk. |
| Fire! It goes 250 feet |
2003 Punkin Chunk
After winding rope bundles late into the night Thursday before the 2002 Punkin Chunk, we packed up, traveled to Delaware, assembled and fired Mista Ballista for the first time.
Our first shots broke pumpkins, but they did go forward about 100 feet with minimal tightening of our rope bundles.
Additional Pages for Mista Ballista
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Mista Ballista
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Mista Ballista is _Team Tormentum's_ *Torsion Division* competition catapult.
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Mista Ballista : Modiolus and Epizygis
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In 2008, Dave devised a new system for managing the torsion in Mista Ballista with his friends Karl Hamm and Kevin Cheney.
This represents a large investment in our machine in these custom parts.
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Mista Ballista : Bowstring
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The bowstring has been one of the most challenging pieces of our torsion engine. It is the last piece to get right, and has been the most likely part to fail in any given year.
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Mista Ballista : Rope Bundles
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The rope bundles are the main engine of the machine. The framework that holds
everything together is about 24 ft long, and 6 feet tall.
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Mista Ballista : 2005 Rope bundle Upgrade
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At the 2004 chunk the main stanchions for the torsion frames were bent by the impact of the arms.
You can see the animation of when this happened on the Mista Ballista Arms page.
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Mista Ballista : 2006 Rope Bundle Reconfiguration
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In 2005 we broke our fancy fiberglass arms. In 2006 we got the new carbon fiber arms
and video taped them in action in the summer at our 2006 History Chunk. This led us to discover how much they bounced around
the outer stanchions. We were getting multiple recoils after every shot, sometimes back at least 30 degrees. That was also just with 2000 lbs of pullback, which is much less than we expect to use in competition.
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Mista Ballista : Frame
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The framework for the Ballista had to be built strong enough to resist the pullback, and to hold up
the 2500 pounds we currently estimate of our engine. It must also push it up 16 feet in the air!
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Mista Ballista : Trailer
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One of our goals for the 2003 season is to acquire a dedicated trailer for Mista Ballista.
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Mista Ballista : Torsion
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Mista Ballista's engine operates on torsion from twisted rope bundles. One of the biggest challenges
of torsion for this machine has been adding the twist. An onager is pretty straight forward in that a large lever and gravity can be used. With our ballista, the direction of twist is sideways, so an alternate means of twisting is needed.
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Mista Ballista : Arms
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After the failure of our arms in 2007, a new tactic was needed. Dave contacted his friends Karl Hamm and Kevin Cheney about designing
and building a set of ballista arms out of aluminum. Aluminum was chosen for its strength and light weight.
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Mista Ballista : Deployment
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To travel to different chunkin' locations, we need to pack the system down onto our trailer.
Deploying from the folded up position is challenging and time consuming, taking a day and a half
at the 2002 chunk. This year at the 2003 Punkin Chunk, we were done in about 4 hours.
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Mista Ballista : Hydraulic and Electric Power
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Mista Ballista uses hydraulics for lifting the engine to a 45 degree angle for firing, and also for winding the cord bundles.
We also like having electricity on hand since Mr. B has a tendency to break, and need on-field repairs. This page describes
what we are using to power up the system.
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Mista Ballista : Mystery Parts
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All winter during 2003 we have been collecting the parts we need to accomplish our 2003 chunk goals.
Here are a bunch of pictures of these random parts. Can you guess what they are for?
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Mista Ballista : Modiolus and Epizygis 2007
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This page describes the Modiolus and Epizygis system we used from 2002 through 2007. In 2008 we developed
a new system for twisting up Mista Ballista.
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Mista Ballista : Torsion 2007
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All torsion catapults depend on twisting the rope bundles to create the engine to drive the catapult. Mista Ballista went through
many phases as we attempted to add more power every year to our throw. This page describes the obsolete systems
we'd used in the past.
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Mista Ballista : Arms 2006 - 2007
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This page describes the construction of our dearly departed Carbon Fiber composite arms. We miss them.
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Mista Ballista : Failed Arms
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Building an arm for a torsion machine this large has proven to be very challenging.
Based on the experiences of our competitors, who also keep breaking arms, we find that
we are not alone in this dilemma.
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