Whatever the original question was about, this has resulted in a very good discussion of flow rates and bottlenecks in the pneumatics system to which I would like to contribute.
FIRST contends in the Q&A that the diameter of the tubing has been specifically chosen to restrict flow rates in the system, but Daniel's comments have encouraged me to look at some of the specs.
The
FESTO valve, for instance, is rated at 14 "cfm"... I presume they mean scfm, which is about the same as the flow rate of the
main system regulator. This means that if you are trying to fill a large cylinder quickly, putting two valves in parallel to that cylinder might speed things up a bit, but would mostly transfer the bottleneck right back to the main regulator. You're stuck with a 14 scfm bottleneck either way... which at 60psi works out to something like 100 cubic inches of compressed air per second.
Now let me add a generous quantity of "IMHOs" around here... my thermo and fluids marks at university weren't that great to begin with, and that was 20 years ago, but it seems to me that if the tubing is not the bottleneck that the way to fill a cylinder most quickly would be to put two or three of the clippard tanks downstream of the regulator (and thus only at 60 psi, but past one bottleneck) and use two or three valves in parallel to control the motion of the cylinder. This reduces the total amount of stored energy in the system, but may allow for higher flow rates, albeit for a briefer period of time.
If the tubing was the bottleneck (and my only evidence for that is the GDC's comments in the Q&A... which contradicts both my "gut feeling" and Daniel's assertions, but comes from a usually reliable source) then rather than using say, a 2"x8" cylinder, you could use two 1.5x8" cylinders to get similar force at a higher flow rate.
Or, as others have suggested, you could preload a cylinder by using a longer cylinder than needed, latching it in position, pressurizing it, and then allowing the gas to expand completely free of bottlenecks.
And if you're thinking of doing that, you probably want to make sure you read team update #5 about trackball launcher safety!
Jason