Re: Ultimate Punkin Chunkin
RPM,
I understood the military has been working on a steam powered cannon. (Supposedly without much luck.) Harp project looks like one really big gun powder cannon.
I do know they've worked on just about every possible method for launching projectiles. I even saw plans for a tiny centrifugal BB gun, spun by an electric motor. (If it works for BB's, it'll work for bigger stuff.) Problem has been getting the acceleration to match that of gun powder and still pack it in a small space.
SHF