Check this Torsion Ballista made of lasercut 3mm cardboard! We got inspired by Leonardo Da Vinci's weapons.

Thank's to Francesco Petracca and Fulvio Gabriele Volpi

Step 1: Drawing for Laser Cut

Step 2: Assembly the Components

Assembly the components and paste the wings of the torsion springs.

Step 3: Make the Torsion Springs

use elastic bands fot the torsion springs. You can alter  the tension of the torsion springs changing the position of the screws in the 3 holes in the front.
Wind the springs...

Step 4: Wind and Shot!