How much air would this use?

I know I could probably look into myself but I was wondering with other people’s experiences, how much air would apnumetic cylinder like this one use? I am trying to think of ways to make our robot better and I was wondering how many tanks we would need to extend and retract this roughly 6 to 8 times. We don’t have a compressor on our robot, or any other pneumatic systems. This would be used for our kicker for the ball, instead of a motor with a paddle, we would add this to force it directly forward into the wheels, if that makes sense.

Pressure1 * Volume1 = Pressure2 * Volume2 (with some atmosphere accounting as well)

Pressure 1 = Storage Pressure (at tanks)
Volume 1 = Total Volume of all tanks
Pressure 2 = Working Pressure (at cylinder)
Volume 2 = Volume of extend + Volume of retract for entirety of match (note - they aren’t quite the same)

We used this simple equation to figure out how many tanks we would need to extend/retract our intake (3" stroke, 1.25" bore, up to 6 times in a match), kick/hold cylinders (1" stroke, 0.75" bore, up to 8 times in a match) and shifting cylinders (0.5" stroke, 0.75" bore, up to 4 times in a match). Once we had an exact amount of tanks (2 for us) we added one tank as a buffer between our calculations and what our calculations didn’t account for.

If we keep the pneumatics topped off at 110 PSI (literally have the kids tether/enable in queue the match before), we haven’t had a problem maintaining > 60 PSI.

For future questions, I would suggest this excel calculator created by Paul Copioli: http://www.chiefdelphi.com/media/papers/3166

It has an air usage calculator but also a calculator for center-to-center hole spacing for chain, and a in depth calculator combining multiple different motors within one gearbox.

Paul’s Calculator and JVN’s Design Calc are two things always open for me during build season for solving design problems like yours.

Wow! This thing is way easier than what we came up with and is very close to our final results. Thanks for a re-link!

Now I’m itching to modify Paul’s calculator to cover multiple working pressure pneumatic systems. Or possibly toss in compressor calculations, but that’d get complicated quickly…

The best way to figure that out is to test it. It’s not too difficult to make a basic pneumatic set up with it, all you need to do is plumb in a solenoid to the cylinder, and then try different amounts of tanks, you should be fine with 2-3 tanks.

This saying is a bit of a pet peeve for me.

Why not do the math first, then test exactly what the math says? It could save you from throwing unnecessary tanks at a pneumatic system, something too many teams do.

I know, It was a recommended starting place. Do the math and the testing then decide how many you need, keep in mind that you don’t want to run until you have empty tanks, you want to run until your stored reaches below your working. Usually when someone says “I think” or “it will be fine” it’s never just “fine”.

Weighing in at about .64lbs a piece* (Black Clippard Tanks), there is absolutely a point where you can reach too many tanks…

Agreed, there is such thing, account for what you need and then add a little more.

In 2014, Warlords (2485) found that a 5gal sheet metal tank was a more efficient solution weight and volume wise compared to the necessary amount of black Clippard tanks given the air usage of their pneumatic catapult.

We wanted something like that last year, but we thought all of the large tanks like that we found would never pass inspection.

Why not? What rules were you concerned about?

The only real good one we found was clearly labeled “not to be refilled”.

Huh? Searching 5 gallon air tank on Google shows many results of refillable air tanks.

I was not the person in charge of researching air tanks, I just know what I was told. That is the past now, its a new year, and we only need 3 tanks!