Human Powered Pneumatic Air Cannon

I can only speak for my friends and I.

Growing up we tended to have a destructive streak (i.e., building enormous slingshots and launching objects from our front yards, tempting fate, etc.). From what I saw today, I think the Human-Powered Pneumatic Air Can is a direct extension of this behavior, albeit at the college level.

This was a scientific collaboration that far exceeded what I had imagined while walking up to the display under discussion. Students from the Colleges of Civil and Mechanical Engineering had teamed up to create a surprisingly powerful air cannon powered by human-generated air compression. They hosted a human-powered “pumpkin-chucking contest” in September of 2007 and took 1st place by firing a projectile a distance-setting record of 622 feet.

Today, however, they broke their own record and put a new one in its place. Try beating 705 feet. The group had actually fired one farther than that but the near 5 lb. pumpkin was nowhere to be found. What distinguishes this from everyday destructive tendencies is the group’s apparent scientific approach - which is based in accuracy, measurement and proof.

This gang of destruction-bent RIT students includes Corey Smith, Tyler Bigham, Kane Mc Afee, Andrew Van Wagoner and Nick Purciello. They create a good time by making this thing work. They’ve got a 21-speed mountain bike on their side. Its rear tire and tube have been removed and they use human pedal power to run an air compressor via a serpentine belt that is attached to the rim of the bicycle.

This compressor is then hooked up to a compressor tank with a fitting welded on to it that houses a 3” ball valve. That, in turn, is attached to a 6-foot barrel. The team has acquired a special sponsor- the $300 valve on the air can was generously provided by Debbie Supply in East Rochester, NY.

This is where it starts to get really good…

Compressed air builds in the tank at anywhere form 30-80psi. When the time is right, the level is pulled and the valve releases all of that pent-up pressure. The projectile is fired, aimed safely away from the watching crowd. Watching the anticipation amongst the audience build as they waited to witness this creation in action was amazing.

Squash, cantaloupe, pineapples, coconuts, 2-liter soda bottles and (e-gads!) raw loaves of turkey were fired. I so wish I hadn’t missed those! There was an extra demo launched on my behalf and was asked if I preferred “distance” or “destruction.” Of course, I went with the latter. The cannon was loaded much like a conventional cannon, with a ramrod used to force the projectile into the barrel (PVC pipe cut into 4-5” sections which were bound by duct tape, wrapped in shop rags and secured with plastic ties).

The projectile shot out at 80 psi to blow through a wooden crate…all in the name of science. Thanks for the souvenir, guys. I’ll treasure that 1-inch thick, wooden shrapnel as long as I live.