We do a similar thing for our air cannon, but we use the sleeve of the shirt rather than a rolled up cuff. Lay the shirt out flat, neck away from you, sleeves out. Accordion fold from bottom to top (about 5-6" or so folds for a thin large or thick medium). Roll from one sleeve towards the other, and flip the last few inches of the sleeve inside out around the roll (like rolling socks). The larger the shirt, the longer the original folds need to be to keep the rolled up shirt the same diameter; fortunately, the sleeves get larger as well. With a bit of practice, some of our team members were able to get the shirt to come unrolled while in descent.
343 has had ours since 2008 when we built it on a prototype drive base we had designed. Here’s a link to the thread about it.
Some things we REALLY like about it.
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It is the old radio control so from everything off to shooting stuff takes about 60 seconds tops.
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having 2 batteries on board significantly increases our run time which is very helpful for longer demos like parades (it can run no issues on just 1 battery if need be)
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2 on-board compressors means that we are not concerned about running out of air frequently.
We do use just straight compressed air, no CO2, with a largely FRC legal pneumatics system. I can’t quote the exact tank size but it is a metal tank similar to ones found on portable compressors like this one. We use 1/4 in line everywhere, but as long as we get a good seal in the barrel we can put ball pit balls on the roof of a 2 story building.
We have used and abused this thing for almost 10 years now and have had no major complaints.
Can you comment a bit more about this? We upgraded “Lola” this summer from compressed air to CO2 because of poor performance with compressed air. The old system had a compressor (running through a beefy inverter) with a 5 gallon air tank at 100psi. We could only give off three pretty meagre (40psi) shots before the compressor needed to run again, and it would take like four minutes to recharge. By contrast the CO2 is good for almost 100 shots on a tank. Do you not have the same issue? What psi do you run your high and low-pressure reservoirs at?
My team also used compressed air. Using a 1 inch solenoid at ~50psi got us about 50 feet of range and that was with a fair amount of air leaking. What we did instead of trying to fit and power a compressor on the robot is just use a standard shop compressor offline and we had a 5 gallon high pressure tank at ~120 psi and a 1 gal shot tank at 50 psi. We easily had enough air for 10 shots which was fine because we only had 8 barrels.
By going with the offline compressor, we went from a robot that would devour batteries like crazy to one that only sips power. We are also able to quickly refill the air on the robot because the compressor can fill up while the robot is demoing and then we can just transfer the air. And because we are not trying to power the compressor off of the robot, we can use a much more powerful one which refills faster.