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Originally Posted by DampRobot
You should be able to fit a pneumatic system in 30lbs withholding allowance fairly easily, especially considering almost all of it will be COTS parts. You'll have to do a of plumbing and testing the system on Thursday (especially considering it doesn't sound like you've done one before), but this is a time issue instead of weight. Read through all the official materials on pneumatics from FIRST so you can make sure to build a legal system, make a solid plan (if you can, CAD out the location of tanks/solenoids/compressor), and then ask around for someone really experienced with pneumatics as soon as you get to competition. You'll need their help putting things together the first time around, especially finding and fixing leaks.
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Incidentally, the withholding limit is just under how much weight we can add onto the currently functional robot and still be under the magical 120 lbs. It wasn't the 30 lbs (is it still 45 now, for MAR?) withholding limit I was talking about, but the weight we could add on the robot. Truth be told, I forgot there was a withholding limit
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Quote:
Originally Posted by DampRobot
I would use the black Clippard tanks any day over the metal ones, especially considering weight is a concern. The problems (which frankly, in my opinion have been dwelt on a bit too long) were with the white tanks, and unless you physically damage the black tanks, you won't have them explode on you. The metal tanks weigh a ton, and only store a tiny bit of air compared to the plastic ones.
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Well, the only concern that I have with the black plastic tanks is that they're rated for about 35 to 100 degrees F, same as the white ones I believe. In New Jersey at this time of the year there is still a risk of the temperatures dropping that low (though it's getting to the point where that isn't *nearly* that much of a concern). My point is that if the robot is stored outside overnight (ie. unheated garage, which has happened on the weekends), then we might induce thermal fracture on the tanks. I've heard fabric around the tanks will help mitigate some of the damage from explision, but safety is still a concern.
Quote:
Originally Posted by DampRobot
The teams talking about two pressure levels were likely only referring to the stored (in the tanks/off the compressor) pressure and working pressure (in the cylenders/solenoids/off the regulator). If they weren't, they had an illegal system. There's no restriction on whether you have tanks above or bellow the 120 psi level. You can keep them on the 60 psi side if you want.
There's no limit on number of tanks, except the rules for the robot size and weight (you can't have an infinite number of tanks, as they will be too big/heavy).
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Gotcha, thanks. That makes sense.
There was also talk of using some interesting pneumatics physics where, between 3 pistons, they were able to achieve (if I remember correctly) 250% of the normal psi? Is this even possible, or am I simply remembering wrong?
Quote:
Originally Posted by DampRobot
Figuring out how to build a pneumatic catapult (which sounds like the way to go, from what I've heard on CD) is something that needs either prototyping or for you to copy someone else's design. It takes a fair amount of iteration to get a system that will throw the ball exactly how you want it, and I certainly wouldn't build your final mechanism without doing a bit of prototyping and research first. I hope someone who actually built a pneumatic catapult will chime in on this thread.
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We will certainly be doing some prototyping before adding onto the robot. The plan is to get prototypes and basic testing done before the weekend, then spend the weekend constructing a system to actually put onto the robot.