Ballista Jr is Team Tormentum's first ballista, and first torsion machine.

Construction started in 1999. It took us a very very long time to find all the parts that worked. We thought we'd build a medium size, cheap machine to experiment with, but we were wrong. After many failed attempts to twist up the rope without breaking everything, we eventually got a nice pair of metal rope holders (Modioli) made from channel and plate steel cut kindly cut to shape by my brother.

Our first successful day of shooting stuff with the ballista. The 8 to one pulley (used on Juggernaut 2) came in handy for pulling back on this burly machine.

Here is a close up of our draw back system. That odd looking gizmo pulling back the bowstring failed horribly as a trigger mechanism.

Roger attempts to extract our pin from the trigger. Pull! Harder! Yearg! Turns out, he could not pull out the trigger pin.

Kevin pulls back on the bowstring.

A picture from the front.

A close up of a rope bundle at night. It appears we were also trying to shoot down the cat.

On Ballista Jr's final days before deconstruction, I snapped a few more close up pictures of its parts. Here are a couple

One of Ballista Jr's engines. The metal system was made using cutting torches and grinders only. No pieces were welded together.
The Epizygis was cut off a bridge I beam I found in the woods (near a bridge, naturally.)
The Modiolus was made from some channel with a hole cut in it, and two slots in the angled part to hold the Epizygis.
The washer below the Modiolus is two strips of metal, also cut off the I beam. We hoped the two strips would cut down of friction.
Inside the metal is a PVC plastic sleeve designed to protect the rope from the rougher bits.

A close up one rope bundle.

Tips and Tricks

To tighten our cord bundle, we used a 2x4 with a bit of rope tied to the end. Loop the rope around the end of the epizygis (a bowline works well.) Then lean the beam across the breadth of the modiolus, and you have a giant torsion lever. We tightened Ballista Jr till it broke. :(

For our rope choice, we went with the cheapest rope at Home Depot at the 1/2 inch think variety. You can use very thick line as long as it is a fiber twist, and not a weave over a cotton (or other) core. The fiber twist is made of many small fibers, so there is no advantage to using a smaller rope except for packing the modiolus.

Videos

We captured a few of our more successful moments (and funny haircuts) on video which Kevin has recently uploaded into the Google video service.

Google Video Service Ballista Jr 1

Information: Here Roger test fires ballista jr by hand. 48 sec - Jul 1, 2006

This next video is funny. No-one but the cameraman seems to have seen where the "arrow" went.

Google Video Service Ballista Jr 2

Information: Another test of Ballista jr, this time using a bolt. 43 sec - Jul 1, 2006