What are some of the advantages/disadvantages of a single flywheel compared to a single flywheel/linear puncher hybrid other than the number of motors used by each design?
I have been in favor of a hybrid for a while but in the finals at the North Texas State Competition I believe that 4 of the 6 teams were only single flywheels with faster drive trains.
The only advantages a single flywheel has over a hybrid single flywheel/LP are size and weight. With just a single flywheel, you have 1 launcher, which will always be less massive and occupy less volume than that same launcher and an additional one (stuff must have positive volume and mass). The mass is not usually a huge issue unless you are pushing the limits of your drive regarding torque & stalling or only have steel parts. The size difference allows for a less compact lift or a larger intake. Really, it comes down to motor usage, at least in my thought process (I won’t discuss that at length here since it has been explicitly outlawed in this thread and another thread focuses on that debate).
The single flywheel can have a much greater fire rate for driver loads and if tuned right, can have bettor accuracy. Also with a single flywheel you can pick up balls in the corner and shoot them from there instead of having to go to mid-field or the bar. This can be especially beneficial if your opponent is playing defense against you. The downside to the single flywheel is it is much harder to build and tune
It is possible to have a cross between the two, this is what we had around December. Have a 4 motor flywheel (8059a style) and a 2 motor puncher or catapult, have them both shooting preloads at the same time. It would also be able to shoot from anywhere. Though the sacrifice of two motors on the puncher instead of the drive may make it kind of slow.
Interestingly we started with a single flywheel, turned it into a hybrid, and then went back to a single flywheel.
I think the biggest factors in going back were weight, efficiency, and versatility. Even though we tried to use aluminum, our hybrid was pretty heavy (20 or so pounds) and we would probably have been difficult to lift. Also the 2 or 3 puncher motors weren’t used at all when we were doing field, and our 3 motor flywheel really only did bar shots in practice. With a single flywheel we threw the extra motors on drive and made it turbo, so we could be pretty fast, and concentrated on upping our flywheel firing speed. We got really good at doing bar and mid court shots (good for skills as well), and were fast and light.
We sacrificed a bit on full court shooting, but most alliance partners in our area focused on full court so that was fine during elims. Plus if you can clear the field it doesn’t really matter how quickly you shoot preloads.
This does seem like it is the best strategy, though hybrids can be good, I think that the faster drive is better to have than a puncher.
Just wondering, but how were you guys 20 pounds with an all aluminum robot?
Did you have a lift or something?
Well I actually don’t know for sure exactly how much our old robot weighed. It might not have been that much. We used much less material on our most recent one and I know it weighs 13 pounds. We’re also a first year team so our first robots were (still are) just bad, with a lot of unnecessary metal. I suppose if we built it now we could get it around 14 or 15 pounds with the puncher, but my statement about the drive still stands, as having 6 motors turbo geared is much faster and more stable than our hybrid’s 4 motor drive.
Well the worst advantage is that if the worst possible case scenario came, the max score you could potentially score is 120 points because of 24 preloads. This is because most single flywheel hybrids have flywheels that can only shoot from the bars. So basically if there were a robot on your oppenent that could not do anything. All they would have to do to help there alliance is to park their robot in front of the bar and guard it. So i would say that is the only disadvantage to this design. However i can predict that this will be the mainstream design at the world championships unless it is a single flywheel like discobots where they can shoot 4 balls per second with 100% accuracy.
If you robot is only able to shoot from the bar and not any further, that is bad design. With 2 or 3 motors, you can easily get a flywheel that shoots at midfield at 1 bps. Also, most hybrid robots have shooting positions other than the bar in case they get blocked.
Check out my post on this thread https://vexforum.com/t/hybrid-design-flaws/33963/1