Quote:
Originally Posted by fovea1959
so what did you use for barrel and 1/3xbarrel diameter tubing?
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We originally had a 2" i.d. barrel and 3/4" port valves. We increased later to a 3" barrel, which helped with the footballs we were launching by reducing friction, but did not really increase the flight length of t-shirts that we had to roll "larger" to fit. We believe this is because the air flow rate was limited by the valve. Our calculations show that we could get better range if we went to 1" valves, but we haven't tested this out yet.
We also figured out
how to roll t-shirts to shoot in the cannon that requires no tape, thread, zip tie, or other binding. Lots of other good tips in that thread.
We're in the process of improving for upcoming football games. A picture of the current cannon (taken Monday evening) is
here. We did not change the barrels out for metal yet, but will do so before making the switch to 1" valves. We definitely do not have any PVC upstream of the valve. We've added a speaker this year, new wheels, steerable turret, LEDs, and are working on a cowling that will make it look more like a tank.