Our original idea was to build a water balloon launcher designed after a Ballista, using 5 fiberglass rods as the power. It had a carriage made from 2 aluminum side plates with ball bearings, the main track was made of a piece of extruded aluminum, called 80/20, it was .75 x 3 x 48.


This design worked quite well, but it didn't shoot far enough, because the actual movement of the carriage was only 30 inches, which was not enough to accelerate it to sufficient speed. This one was however, very repeatable, and would hit within 6 inches every time.

 


We decided to make a new one, with almost 8 feet pf travel, and just using a bungee this time, because it would have snapped the bow rods at any more then 35 inches of draw. So our new one was mad of an 8 foot piece of extruded aluminum, this time 1.5 x 3