21st Century 3D Printed Giant Crossbow

grabcad

I only learned about this competition 4 days prior to deadline, and decided to give it a shot. I wanted to create a Giant Crossbow, consisting of as few parts as possible, press fit assembly, and no other parts required. It had to be powerful and all parts should fit to be printed on a Makerbot Replicator. PLA is very hard, so the bows are designed very long, with about equal stress along the length. It consist of just 8 parts, including a ball. I haven't got access to a 3D printer at the moment, but I've printed tons of thing of a Dimension SST 1200ES in my last company. It should fit, only unknown is the bows strength, is it weak or strong, will the bows break at full 80 mm pull back? Bow might need some adjustment, but my gut feeling says this might work.