First of all a big thanks to the folks at 1726 for posting some video of their trackball launcher last weekend. We had spent the previous week doing tests, mock-ups and calculations and were pretty darn sure we could launch the ball successfully… but still had a few doubts. When we saw their video we KNEW we were on the right path.
We are using four 1.5" x 8" cylinders, with about 2" of preload, backed by a couple of clippard tanks at 60psi downstream of the valve. The launcher starts out just slightly “over centre”, so it locks itself in position until triggered… on the final version by a small cylinder, here by a medium to large sized human.
The 2x4’s, placed on the railing to simulate an overpass are actually at 7’6". And we clear them by… oh… 18" or so (technically somewhat short of the “mile” somewhat over-enthusiasticly reported in the third video). No data on air consumption yet, other than to say that we still have some R&D to do on that… and then there is the whole electronics and programming thing to get finished, and we have to make sure we can still load the ball by nailing it into a wall with our front end. But here’s some clips of the “fun stuff”.
If only we hadn’t spent the first two weeks trying to design an arm that would fit in the 80" cylinder… this is actually one of the simpler “primary scoring mechanisms” we have built for FRC in the past five years.
Four 1.5" x 8" cylinders! We only have two 1.5" x 8" cylinders with two tanks downstream, and we are tight for air consumption (it takes 10-15 sec to refill the system)! Anyways it is interesting to see all the designs like this popping up. We took a week to start working on this one, realizing quickly that a robot with an arm would have very little chance of winning if there are many robot with catapults that don’t need to stop moving to hurdle (not to mention the armed robots more likely to topple over). Our design is mounted a foot off the ground, and will launch the ball about 3-4 inches over the ends of the rack, and is about 18inches over at the apex. So we will be tweaking our system hoping for the results you have been seeing… just with less air required. Again impressive results, and I hope it works out for you
Yeah, air is going to be an issue… although perhaps not as huge an issue as we might think as we’ve got lots of room to “dial back” on the shooter power if we have to. For now, however, just blasting the thing around is pretty fun, as is contemplating the idea of boosting power a bit and making a shot over the divider and overpass and scoring from the “other” side of the field. Not a particularly useful strategy, perhaps, but certainly fun to try.
As for picking up the ball, we had great success earlier this year by just smashing it into a wall, then driving underneath it as it bounced into the air. After spending the first couple weeks bemoaning how difficult it was to work with a ball that big we finally came to the realization that there were benefits to a giant trackball (it’s hard to miss!) as well as drawbacks. Now that we’ve got the launcher on board we’re going to try that again today.
We’ve got a long way to go before we are ready to put this thing in a crate!