Quote:
Originally Posted by artdutra04
The FRC-legal pneumatics are too puny for air cannons. You need at least 3/4" NPT fittings to get a flow rate good enough to shoot a tee-shirt a considerable distance; the biggest fittings in the KoP are only 1/4" NPT.
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Uh oh... i was trying to design one of these air cannons on a dime using a 3" internal diameter barrel 12" long (abs plastic, .25" wall thickness) and was going to just use four of the 16cu in clippard air cylinders as air storage.... I was not however using standard IFI air solenoids, i got my hands on some used (free) Mac Valves with a Cv constant of 30, 1/4" npt.
With the hose included, if me and my Machinery's Handbook calculations were right, I should get an output rate from each clippard/valve pair of 38CFM, or 152CFM for all four pairs. If i switch that over from CFM to cubic inches/second it is 4377.6 cuin/sec. The volume of my barrel is 84.823cu in, so that should fill the barrel (and eject the tee shirt) in 0.0193 seconds... which is 35mph.
Was this velocity not high enough? It stands to reason if i double the cylinder/valve pairs i should be able to get this up to 70mph if it isnt. Or, is there another cheap alrternative (remember clippard cylinders are cheap and the valves i'm using are free (have 10))? What's the cheapest way to switch that much air on with one valve? Whats this I hear about irrigation valves?
Sorry, i'm new to the T-Shirt cannon (high flow pneumatics) business...
Any help would be much appreciated.
-q