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Unread 16-01-2014, 01:53
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Re: Creating pneumatic launchers

Quote:
Originally Posted by ToddF View Post
Note that with the same stroke length, it takes the same volume of gas to fill both of these configurations. With only a single solenoid valve supplying the gas, they fill in exactly the same time. The thing that allows the second configuration to fill faster in a FIRST robot is the ability to use two valves to fill the same volume.

In the real world, using a single large cylinder and filling with two valves would be more weight efficient than the second configuration mentioned. I hate seeing people tossing around generalities like "larger cylinders are slower" without stating the underlying assumptions behind the specific application that makes it so. I fear we're teaching our students design "rules" which are only true in the restricted world of FIRST robotics, but are completely reversed in the real world.

Another approach would be to use the single cylinder from configuration 1, and use a faster flowing valve, a perfectly valid option this year. People are finding legal valves with more than twice the flow capacity than previously legal valves.
As long as you are taking my comments out of context, then you are right. That said, I was only giving an example of equal force provided with two commonly available cylinders.

In FIRST, access to a large variety of parts is a given. Although, many teams are on restricted budgets and thus can not afford to by valves just to attain a higher flow rate. These teams need to be creative with what they do have access to.

There are ways to actually exceed the flow rate that is available from even the highest flow valves that are legal within the rules this year.
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