Hiya fellas,
my first comp I join 
so i taught about a huge cannon mounted to a kinda ballon thing. The pilot will be a goblinlike creature. I hope it fits still into the guidelines, as nothing was mentioned that the pilot has to be human.
the 3 flat cylinders are gonna be gear wheels i think, have to overthink the mecanism though
i would draw a concept sketch, if I could paint
so heres my start:









