So my team and I built our very first flywheel, and it kind of sucks. Its a vertical flywheel, geared 7:1 with 2 hs motors. We’ve eliminated almost all of the friction, and it has minimal slop. spins 4 wheels, and has rollers push the balls up into the wheel. The only real issue is that no matter how we adjust the hood, the ball will only shoot maybe half a foot up, and 2 feet across. We do not yet have rubber banding on the wheels, and we don’t have anti-slip on the hood. (We ordered them yesterday.)
Are there any improvements we could make other than rubber banding the wheels and anti-slip on the hood? Any flywheel improvement tricks? Or will we have to do a total rebuild to achieve success? I’ll try and get a video of it in action tomorrow.
Since the balls this year are hard, something in your system needs to be compressible or stretchy. That can be your flywheel itself (not really recommended, but rubber bands would be helpful for grip), or your backplate. For the backplate you can use stacked grip-mat or foam, or you can mount the backplate on rubber links. The goal is to allow the flywheel a significant amount of time to contact the ball so that it can accelerate the ball as much as possible. Of course, too much pressure is bad so you’ll have to trial and error it a bit.
7:1 sounds too slow for the flywheel.
is it? What gear ratio would you advise?
By hs I’m assuming you mean 160RPM 393 motors.
160 x 7 = 1120rpm. This isn’t really fast enough except for maybe the middle flag at close range. With 5in wheels you might be able to get a bit higher but I doubt the top flag is possible. For 4in wheels you’re going to want somewhere in the neighborhood of 2000rpm for close range (21:1 would work nicely), and 3000ish rpm for long(er) range. The former is possible with 2 393’s but prone to tripping PTCs and highly dependent on build quality, and the latter is pretty much impossible on 2 393’s.
Disclaimer: I haven’t verified any of these numbers with real world testing (save some 5in testing). They were extrapolated from my experiences with my 5in flywheel this year and both 4in and 5in flywheels in NBN.
hmm… okay, we’ll probably slap on 2 more motors, and gear it 21:1 Thanks for the help
One more warning:
These flywheels contain a surprising amount of energy. Try to take measures to prevent that energy from being dumped back into your motors. In NBN flywheels were notorious for destroying internal motor gears, so some teams implemented slew rate control, and even ratchets to prevent this from happening.
okay… I know how a ratchet works, so maybe I’ll do that.
1:100. Best for shattering flags
Our team is testing a 49:1 with two high speed motors. We have insane range and more than enough force to turn the flags. The motors also have not burned out during testing so far
dang really? 49:1 with only 2 hs motors? That seems crazy, you must have superb build qualy.
I should’ve known that 100:1 would do the trick. I went to the effort of 10000:1, but looks like I went overboard. Our strategy was for the sonic boom to render our opponents utterly confused, and to detonate all flags, and platform Plexiglas so we can score all of the caps and win.
anyways, we succeeded, and build a 4 motor hs 21:1 flywheel, works quite nicely, even without any adjustments like anti-slipping the hood or rubber banding the wheels. Thanks a lot for the tips. =)
Please explain how this is possible, especially with 2 HS motors. I would think they shouldn’t even turn let alone achieve nearly 8k RPM…
Yea, what’s up with that? 49:1 is insane. Probably way overkill.
Nice! You’re going to want to add some compressible material to your backplate to increase launch distance though. Also swap out those bent axles in your gearbox.
I’ll look at it again today just to confirm, but I believe it is two 7:1 ratios. Yes it may be slightly overkill but we have almost unlimited range
Sorry guys the ratio was wrong. It is less than 49:1 my bad really sorry for any confusion caused.
thanks. yup, we’r going to triple layer it with anti-slip, we didn’t have any at the time, so we ordered some.
do we have bent axles? wow hadn’t noticed those thanks
I can verify that one of our team’s flywheels spins at 1777.77… RPM and it almost hits the middle flag with enough force. My guess is that above 1800 RPM is a good area for close range shooting and 2700 RPMs might be sufficient for longer range.,
sounds about right. We can hit all of the flags, middle flags from both driving right up to the posts, or from the very back of the field, high flags from just in front of the platforms, or from just behind the platforms, so we have pretty easy to remember shooting positions. we can also do 2 balls at once if we ever wanted to.