Hello, and welcome to ChiefDelphi As the coach for a fairly successful FTC team, I believe I can help.
a.) Lexan or sheet Aluminum. Be sure to look at the rules for allowed thicknesses. Be sure to round off corners and file down the sharp edges. Lexan has a tendency to keep its shape if you heat it up while you bend it. Aluminum is typically easier to work with in general so long as you’re careful about sharp corners/edges.
b.) Ya know, the students on 1885 argued this for 2 months. Some argued it so fervently that 1 month before their first competition they had nothing built (except for a standard drive train). I walked in one day and told them to simplify the design or they were all fired [from the metaphorical company they worked for]. They did that and have had alot of success since that day. So perhaps you could look at a slightly revised strategy, a different way to expand ball capacity, or ignore ball capacity in general.
Hint: investigate crocheting your own net using the allowed rope. It’s not always a good idea, but maybe it fits your design. In the offseason perhaps you could investigate a linear slide, folding, or other system.
Thank you very much for the reply, you were pretty helpful with the contribution to the idea to make the robot.
Lately we have been working on the mechanism that picks up the balls, but we have had some difficulties. Later on we will post a video on youtube.
The picture above is a picture of the picking up mechanism. This picking up mechnism has problems. The main problem is trying to make the rubberband as you can see above stay still during action. When we run the rubber band, the rubber bands move to one side making the clump together in the end. Please post any ideas or any thoughts on the matter.
On a brighter note we have built a working shooting mechanism. We will try to have a video link later on to show how the shooter works in action.
After arguing on point b for two months and getting fired, 1885 actually found that our robot’s mechanisms allow for plenty of ball storage. We have no ‘devoted’ place to store wiffle balls, but because of how they travel through our robot, we found that we don’t really need extra storage.
Unless your bot is centered around getting all of its balls in the outer goal, in which case you’ll probably want to store around 30 balls to comfortably win every game (DE’s max score didn’t break 200, if I recall) without the use of the yellow ball, then don’t worry a ton about ball storage. If you can hold a rack and your 8 preloaded, you’ll do fine.
(On another note, I’m still employed in said company, thankfully).
RobotC forums are pretty active, but that’s primarily for RobotC programming. I’m not aware of any other forums.
2a) You can use lexlan or the metal sheets that are allowed this year.
2b) Extending the frame is not easy, I’m not even sure it’s possible with the lack of sliders and stuff. I recommend experimenting with expanding storage such as expandable buckets made from rope, lexlan, or rubber bands.
Today we found a solution to the problem that we had posted up previously. Instead of using rubberbands to pick up the balls, we had decided to use the non-slip pad, which was an usable resource that was stated in the FTC manual.
Thanks you for reading, and for the previous responses.