Video here:
http://www.youtube.com/user/kyakfsh?feature=mhee
and here:
This looks really good. How many RPM’s is the motor turning at, and why did you choose to use one wheel over two wheels?
Great Job with the single wheel, FIRST Team 2363!!! We are trying a double wheeled shooter lift and we are wondering what type of wheel we should use (for we don’t want to tear up “arena property”). From your video, it seems that the game piece wasn’t torn up by the wheel’s spinning face. What type of wheel or wheel face did you guys use?
My team is also looking at a single axle shooter - jw, what was the distance between your curved backboard, and wheel? We were thinking that 7" was about right, though it will have a bit of adjustability. Anyway, nice prototype
We plan to prototype 3 ideas:
- One wheeled shooter based on old robot, because it’s easy. We first used a drill to power the motor, but didn’t get much speed. Then we used the original CIM motor and gearbox, and started shooting like in the video. Sorry, I don’t know the exact RPMs of the wheel. We did this just to be sure we had an easy fall-back in case our other ideas don’t work out. The spacing started too big, and we added wheel tread to the inside of the hood until it was shooting decently. Drill motor ran Thursday. CIM motor ran Saturday.
- Two wheeled shooter, like those shown all over youtube. We expect to get more distance for the same motor power. Should be running Monday.
- Catapult. We are most excited about this one, and this will probably be where we spend most of our effort. First prototype probably flinging next Saturday.
I’m not from that team, so the following is an educated guess from watching the video.
That looks for all the world like an IFI Wheel from Vex Robotics. I’d guess 8" diameter and 2" wide. You can see the wheel is being direct driven by a CIM powered Andymark Stackerbox. The stackerbox has a 3.57 ratio, so that’s an 8" wheel turning at around 1500 RPM, for a surface speed of around 50 feet per second. What I can’t tell is how much compression on the ball that they’re running…
You’re good, Kevin. I wasn’t with the team when it was built, so I didn’t know those specifics. I’d estimate the current amount of ball compression at about an inch. After a bunch of shooting, the logo graphics on the ball were coming off, but the orange surface was fine.
Well, great job with the shooter, but be careful! I wouldn’t want to see you guys receiving fouls or even tech. fouls for repeated removal of labels!::ouch::
GOOD LUCK!
I’m actually impressed that the only real damage was the logo graphics getting worn off. Veterans of 2006 and 2009 will know that the tolerance for damage to scoring elements is actually pretty high. The 2006 poof balls started looking scruffy after a dozen matches or so. As long as you’re not ripping balls in half with your shooter or tearing out gigantic divots with every shot, you’ll be fine.
Well, I am aware that you can’t rip chunks off of the pieces, but it is very much appreciated for you saying that teams can get away with that type of minimal damage…
…knowing that makes me a little bit calmer, being a “perfectionist” and all…
we prototyped a similar shooter over the weekend as well. We have the results when it came to ball wear. The only thing damaged were the labels. The balls seem to be handling the use well.
Those rules are put in place so that you don’t have a bunch of robots on the field that are destroying game elements keeps FIRST’s cost down and it is just common sense for teams. I’ve never seen a team penalized for popping/damaging a field element but if they see you doing it over and over they will crack down on your robot. Last year at the Championship they had a string of popped tubes on our division so before each match the que-er would feel the front of our robot for sharp edges.
Were those shots taken in sequence or were they only shots that made it in the hoop? Looks very promising for you guys! 
I’d say maybe a third to a quarter of the shots made it to video that was posted. When playing with prototypes, there is always a lot of “playing”. That’s how you begin to get an instinctive feel for what what works and what doesn’t, and what sorts of improvements you want to try in your next iteration.
When prototyping, it’s important not to draw too many negative conclusions about the feasibility of a design. Prototypes often aren’t executed well, and that’s just fine. You are asking, “What could this be if we concentrated on making it as good as it could be?” Your goal is to try a few things very quickly, so you can decide which of several concepts deserves your full development attention. It’s just as important not to lock in on the first idea that shows promise.
Our shooter brainstorming session generated 15 to 20 ideas. We narrowed it down to 3 ideas worth prototyping. We’ll try them all and then make the decision of which will be the one we focus on improving.
We were lucky in that we had this specific hardware already prebuilt, and the only modification necessary to get it shooting was to shim the hood for more ball compression. Our other prototypes will be a bit more crude. It really illuminates the advantages teams with history have over the rookies. This is the first time we have been able to really take advantage of this.
Just for completeness sake, here is some further info.
- CIM motor free speed 5310 RPM
- Stacker gbx reduction 3.57:1
- pitching wheel speed 1487 PM
- pitching wheel tangential speed 51.0 ft/sec
- ball center speed 26.0 ft/sec