# First video of flywheels hitting flags with balls!

W00T! Flywheel specs:
1M v5 200 rpm 16.33:1

nice work, that’s looking super great!

about how much of the time can you get a successful hit?

@JamsG this isn’t a build for accuracy, its not attached to a bot, if you watched the live stream you would know that the concern wasn’t accuracy it was mostly about spinning the flags via the balls.

Nice! This works well… that’s just 1 v5 motor, yes?

Correct, I think it is pretty cool and impressive that it works with only one motor

Just for the reference, how far was the flag? (looked like 10’)
Any idea on your launch speed? Or RPM of the flywheel. From the video, I estimate 5-6m/s…

If it’s 200rpm 16.33:1 I would guess 3670rpm and the diameter of the flywheel looks like 4” the flywheel I think is covering 19.2m/s or have I done my maths wrong?

Nice work!

Assuming it’s set up the same as the other video, he said 200 rpm x25 = 5000 rpm. There is also a layer over the wheel, so its diameter will be greater than 4", but it’s hard to say how much because that layer is squishy to get grip since the balls aren’t squishy.

But, yes, you have made some mistakes in your math: 200*16.33=3266, not 3670. Looks like your physics is correct. Adjusting for x25, fixing the multiplication, and adjusting to 4.2" as a guess, I get 28 m/s for a tangential speed where the near edge of the ball meets the flywheel.

Now, if you want the speed of the ball, you want to remember it’s essentially rolling without slipping along the curved metal on the opposite side of the ball from the flywheel. So the speed of the center of mass of the ball would be about 14 m/s, but that’s assuming the ball actually gets up to the full speed of the flywheel without the flywheel slowing down any. The balls are light, which helps for acceleration. The wheel is being consistently driven, which helps prevent it from slowing down. So hopefully those errors won’t be huge. I’ll go with 90% or so and estimate the ball’s center of mass launching at roughly 12 to 13 m/s. The easy way for @antichamber to check is to film the ball across a background with a measurable scale, ideally using the highest speed and best resolution combination, then go frame by frame just after the initial launch to see just how fast it’s going. That’s also done most easily if the ball is launched horizontally so the vertical axis may be entirely ignored.

I’ve edited the original post for linking to a video that violates the VEX Forum Rules.