Quote:
Originally Posted by DrewMatic
By any chance could you post a picture so I could see your t shirt cannon?  |
The "early season" version of 3946's air cannon was written up by my daughter Veronica with video on
the school newspaper. The guy who was shooting video was not part of the team; he focused more on crowd response than the launcher. The only clear shot of the launcher 'bot is about 1:25 when I'm manually turning it. The 3946 team on the field that evening also includes Matt Marton (our student mentorship award winner for 2015), Jesse Hobson (head coach), and Veronica Michel (author of the article).
When we had a break in home games for several weeks, we did a complete rebuild. The new version is narrower (meaning we can roll it through a door, rather than having to take the barrels off and carry it through sideways), lighter, has shorter, wider, white barrels, and features a rain shield for the electronics made from a rubbermaid tote. We don't have to manually turn the narrower robot as I did the wider one. Note that even on the early robot there is no PVC before the valves, but a painted black iron tank and galvanized pipe. PVC is not rated to handle air pressure: because it breaks rather than tearing (steel tears), it generates way too much shrapnel when it fails. The rebuild this summer will feature better wheels (so it is really a drop center drivetrain), RC steering of the barrel, range control through solenoid timing, a sound system, confetti cannons, programmable LED lighting, and we'll probably also replace the PVC barrels with metal, though even our professional pneumatics guy doesn't sweat an "open" PVC pipe carrying pressure.
Oh, yes - the pressurized air is from a scuba tank, regulated down to about 40-50 psi for storage in the black iron tank. We have 1" pipes from the black iron tank to the solenoid valves, which are 3/4" diameter. Our current system opens the solenoid for a constant 50ms. 60 psi, a 50ms solenoid time, and an orientation due west can toss a t-shirt from the running track over the top of our press box and onto Ninth Street.
We came up with a simple t-shirt roll to load the launcher:
- Lay the t-shirt flat
- Lift the lower hem until the fold reaches the armpit.
- place the next fold even with the "shoulder seams"
- "accordion fold" until you run out of shirt
- Fold the left sleeve over the accordion folded bodice
- Roll from the left side until you are about halfway down the right sleeve
- Flip the end of the right sleeve around the cylinder (much like rolling socks)
- Load the resulting cylinder in the air cannon!
The new 3" barrel works just right for size large heavy weight (e.g. Gildan or FOTL) shirts. For larger or thicker shirts, make a longer cylinder. For smaller or thinner shirts, make shorter "accordion folds" to get the appropriate diameter.