Flywheel help

This year for Turning point our team has decided to prioritize flags for the early season. We have one built and today we tested it and found that we didn’t have enough powe. We were running it with a 5:1 5:1 gear ratio with two motors and have tried several since without posititve results. Any advice?

If you are using 100 RPM 393 motors, your wheel would turn something like 60 RPM. When you do two 5:1 gear-ups, you get 60 x 25 = 1,500 RPM. The rim of the wheel is turning about 300 inches per second. I should think this would be plenty fast enough. Things to check:

  • Do you have enough power? When you gear up you increase speed but reduce torque (or twisting force).

  • Is the shooter pinching the ball a little? If not, most of the potential energy in the wheel is not getting to the ball. This can also be a result of a low-friction interaction between the wheel, the pinch point and the ball.

  • Do you have friction somewhere in the flywheel system that is keeping it from spinning at full speed?

For Nothing But Net, some teams were running 3,000 RPM, but that was a heavier ball that had to fly farther. I think you have a build problem, not a design problem.

We ran the flywheel with some grease on the gears and it helped but it’s still not working well. I was able to stall the flywheel by putting my hand over it. Do we maybe have a torque problem?

Thats normal, if you have a flywheel that wont stall, your missing the point of a flywheel. One issue you guys might have is the “compression” the ball receives as its going through your flywheel. One way to fix this is just to roll the ball through it and see if it smoothly goes through without you touching the ball, just the physical wheel. This is probably the most important step to flywheel tuning.

Nope, that’s totally normal.

There are actually 5 common reasons flywheels don’t shoot far enough, any of which can seriously hurt your shot distance. If you tune each one, you will shoot easily far enough with a 25:1 ratio and 4" wheels.

  1. Friction. Minimize friction. Use grease, test your bearing flats, lube the motors as well, keep your gearbox parallel and flush, and so on. When in doubt, take your motors off and see if your flywheel free spins for at least 15 seconds.

  2. Compression. Higher compression increases friction between the flywheel and the ball, but it also requires more force to get the ball through the hood. Shoot a few, increase the compression, and then shoot a few more. If it goes further than before, increase the compression again, if it doesn’t go as far, decrease the compression again.

  3. Grip. Try putting friction mat on the hood and rubber bands on the flywheel. The better your grip, the less compression you need to shoot, and the faster your recovery rate will be. Slippage is bad!

  4. Inertia. The heavier your flywheel, the more energy it takes to ramp up, but the less energy it loses when the ball is going through. If your flywheel is a feather, it will have no inertia, and it will stop instantly when your ball goes through it. Put 2, 3, or even 4 wheels next to each other to increase weight.

  5. Feeding. If your feeder holds onto the ball for too long, the flywheel will have to waste some of it’s energy to yanking the ball free of the feeder. Make sure your flywheel and feeder are in contact with the ball at the same time for as small a distance as possible, and crank up the speed of the feeder as much as possible to decrease the time it takes for the ball to travel this distance.

Lemme know if anything didn’t make sense. Good luck!