I've been a big fan of this contest for a long time, and have been fascinated by catapults
of all kinds for many years.
I recently saw a video where one of the contestant teams modified their pneumatic cannon
to give some backspin to the pumpkin. I thought that was a great idea -- and it apparently
helped, by providing lift to the pumpkin.
Here are some other thoughts I have about the pneumatic cannon hardware. If I could
find a forum where the contestants go, I'd post it there. But land speed racers, to me,
are of a similar mindset, so I thought I'd post here, to see what you think of my ideas.
(And if you could point me to a punkin' chunkin' forum, I'd appreciate it.)
One of the issues with the pneumatic cannons is that sometimes a pumpkin can't withstand
the forces of launch. Here are some thing's I'd do if I could, and were a contestant:
1. Use an extremely long barrel. I don't know how long is permissible within the rules.
2. Have the bore teflon-coated. I think this is permissible.
3. Design the plumbing for smoother fluid flow (i.e., no small-radius edges or turns in the pathway) from the reservoir tank.
4. Evacuate the barrel ahead of the pumpkin. This could certainly present a challenge, but we can discuss it. I saw a very
impressive live demonstration of how this principle could help. In this demonstration, a regular ping-pong ball was blasted
from a long barrel, and went through both sides of an aluminum can that wasn't restrained. It was just in the path of the
ball!
5. Add additional fluid (gas, not liquid) flow along the launch path just ahead of the muzzle, so the pumpkin doesn't hit "still
air" as suddenly.
6. Use gas (that is less dense than air) to propel the pumpkin. I don't know whether nitrogen or helium or hydrogen are permitted
for this.
7. Preheat the launch gas and the barrel before launch.
8. Use the largest permissible pneumatic reservoir.
9. Use a very large and fast solenoid valve to release the gas. Perhaps use a manifold of several branches that feed into the
launch tube. Each branch would have a very large and fast solenoid valve.
Thanks for all your comments on this.
