Siege World Championship Chunk 2008: Mista Ballista

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World Championship Chunk 2008: Mista Ballista
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Mista Ballista returned to Delaware for the 2008 Punkin Chunk. For the first chunk ever, we drove down with our rope bundles unwound because we still had welding to do.

We left Massachusetts at 1am, and drove until we were on the field at 11am the same day.

Fixing Mr. B

Mr. B and Hatra Ballista's spring frame arrive on the field. Unfortunately, we hadn't had time to put the rope into the bundles before driving down to Delaware. Instead, the rope was stored in two giant trash barrels in a way that was specially configured to simplify winding the bundles.

The team immediately set to work. Jeff drilled new holes in the scutula that lined up with the holes in the new modiolii. Dave, and friend Karl start getting to work with the new trunnion mounts that are needed for the new winding system.

Karl welds professionally, so Dave helps by blocking the wind as Karl tacks down the new trunnion mounts into position.

Also installed were rope retention shims. These wood shims will buffer the rope so that it doesn't deflect over the edge of the modiolus hole.

As the sun begins to set, the new trunnion mounts were completed. The donuts floating in space were required mounting locations for the hydraulic ram which we will use to tighten Mr. B's rope bundles.

Winding, and Twisting Mr. B

On Friday the entire day was spent winding the rope into the rope bundles, followed by twisting the rope up with the new arms installed.

First things first, run the rope through the bundle frame. We fold the rope into multi-strand segments which we feed through the bundle in one pass. The tarp helps keep the rope clean while we work with it.

Jeff takes the usual honors of tipping the rope bundles down from the travel position. The new trunnion mounts appear to form a new type of obstacle dropping on Jeff's head.

Once the bundles and frame is in place, the trunnion (gray) is bolted onto the trunnion mount. Our red hydraulic cylinder is then inserted. We attached a custom connector between the cylinder and our new roller chain. This chain is like bicycle chain, except much, much bigger.

The chain was then wrapped around the modiolus sprocket, measured, and abbreviated to the correct length for our application.

The freshly minted aluminum arms stand waiting to be inserted into the bundle, and then beat upon.

As the sun began to set, one arm was in, and basic torsioning techniques were determined.

Saturday, and Our first shot

While Hatra Ballista was shooting, the team finished tightening up the second bundle with the second arm in it. The new torsioning system was so quick we had time to show the new equipment off to others.

Test pullback shows only a small amount of flex in the arms which also caused the back-stays to deflect slightly. This was considered an acceptable behavior. Also in this image, we added leaf springs to help cushion the blow the arms would take when striking the outer stanchions.

Not satisfied with the current performance, Dave and Karl climb back up on top of the machine to tighten those bundles up a little bit more.

Then we ran out of time. We had to load our pumpkin, and wait for our chance to throw.

I give the pit boss the thumbs up, and he gives me the ok to fire. Mr. B operated as desired, and sent a pumpking out 430 ft.

The Sunday Shim shot

One of the things I (Eric) wanted to try was to increase the "At Rest" angle of the arm. Doing this by adding shims to the inner stanchion would, in theory, cause the arm to not strike the outer stanchion. This worked at the low torsion from Saturday, but when we added even more twist into the ropes on Sunday, our shims didn't stand a chance.

The crushing of the wood in this picture is just from the arm pressing against the wood while adding more torsion. The machine had not yet been test fired.

Our shimming strategy did not work! After adding even more torsion into the bundle, the entire skein just deflected forward from the twisting force applied to the arm. It appears that perhaps nylon is a bit too stretchy for this task.

NOTE: Again I need a pic of Mr. B firing on Sunday. If you have one i can use, let me know.

Unfortunately, we pied our last shot, but a large chunk flew a couple hundred feet past the spotters who were all waiting for our shot 600ft away. Clearly, the farthest toss of our machine yet.

Worse than that, our new arms cracked to the point where we could no longer use them. For both arms, they worked great during pullback, but failed on impact.
Additional Pages for Punkin Chunk 2008
World Championship Chunk 2008 Team Tormentum brought two of our torsion machines to the chunk this year.
World Championship Chunk 2008: Mista Ballista Mista Ballista returned to Delaware for the 2008 Punkin Chunk. For the first chunk ever, we drove down with our rope bundles unwound because we still had welding to do.
World Championship Chunk 2008: Torsion Class Once again, the torsion class ruled the field with massively long distance shots that broke world records, and the usually great Torsion camaraderie.
World Championship Chunk 2008: Hatra Ballista Hatra Ballista Jr went to Delaware for the second time to compete in the _Youth 10 and Under_ division.
World Championship Chunk 2007: 10 and under
World Championship Chunk 2008: Various

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