pneumatic catapults

[Knufire]

Originally Posted by ollien

Maybe I'm misinterpreting the rule and the conclusions you're drawing from it, but no inspector has ever faulted us for having one solenoid for two pistons.

One solenoid for two cylinders is legal. Two solenoids for one cylinder is not legal.

Originally Posted by ollien

Why would filling two pistons from one solenoid, vs 2 pistons from 2 solenoids, be faster?

There used to be a rule that limited the Cv (flow coefficient) of solenoid valves on the robot, causing the solenoid to be a bottleneck in the flow path. That rule has since been removed. However, larger Cv solenoid valves are generally larger and/or heavier, so multiple cylinders on multiple solenoids may be a good alternative depending on your design constraints.

[adciv]

Originally Posted by Knufire

There used to be a rule that limited the Cv (flow coefficient) of solenoid valves on the robot, causing the solenoid to be a bottleneck in the flow path. That rule has since been removed. However, larger Cv solenoid valves are generally larger and/or heavier, so multiple cylinders on multiple solenoids may be a good alternative depending on your design constraints.

To continue on this (sorry, too used to thinking electrical) the other counterpart to this is we are still constrained by the pneumatic size limits which act as an indirect Cv limiter. A fitting and tube withing the existing 1/8th inch port and 0.165 inch inner diameter limit your maximum air flow for each path the air takes.

By the way, watch out for the Cv rating on components. We've seen some come in where the solenoid was advertised at one Cv rating, but the fixtures had only a tiny hole for air to pass through and so the effective Cv rating was significantly smaller.