# Is a 9800 RPM flywheel good?

For us it works but it overheats super quickly. We have air in a can but it doesn’t really work good. Today is feb 8 and my last competition is feb 11. So what I am trying to ask is how to make your motors not overheat so quickly. It is the same problem for the other kids at our school.

Your flywheel should be much, much, much slower. The fastest your flywheel should spin at is 4200 RPM, and even then you will never use that in game. For us, using an 84 tooth gear into a 12 tooth gear with a blue motor cartridge works well with 1 motor.

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9,800 rpm is a little overkill

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First off, HOW is it 9800 RPM? That shouldn’t be possible. Second off, the best way to have it is 3000 RPM, generally. (Blue motor, 5:1 gear ratio).

9800RPM shouldn’t be possible, but that is why it burns out so fast

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We used to have a 9800 rpm flywheel, but we changed the gear reduction to 5500 ish rpm’s, so that it wouldn’t overheat as quickly

As many have said, 9800 is too fast to be sustainable. One of my teams runs a 4200 rpm flywheel (max) with 2 motors, but they typically run it lower than that. With proper compression, 3000 should be fine - two of my teams run 3000 rpm flywheels off one motor, and it achieves the distance they need.

9800 RPM on 600 cartridge, 9800/600 is a gear train ratio of 16.3333333.

Compound gear ratios are a multiplication of the individual ratios, so for instance, an 84 to 12 is a 7:1 ratio, if said 12 tooth was on another shaft with another 84 to 12, the combined ratio would be 7:1 times 7:1, or a total ratio of 49.

From here, it’s just using guess and check with math to find what ratios multiply to 16.33333. We can pretty much assume that the ratio has at least one 84 to 12 ratio because its so high, so 16.333333/7 is 2.333333.

We can equate this ratio as 2.33333 = gear 1/gear 2. To find gear 1, we can guess gear 2 by multiplying possible values for gear 2 times 2.33333. Because this ratio has to be an increase, let’s start with the smaller gears, or 12.

2.33333312 = 28. This is not a gear.
2.3333333
24 = 59.55555. This is not a gear.
2.3333333*36 = 83.9999999. This is so close to 84, we can assume that there is a rounding error or something along the way.

This means to achieve 9800 rpm, you need an 84:12, and an 84:36, where the 84 and the 12 share the same shaft on the two ratios.

All in all, I would suggest you reduce your ratio to around 3000, or a 5:1, or 60:12. This is fast enough to get the disc into the basket, and to shoot from farther distances, not overheating too fast. I would also suggest to change the angle of launch rather than adding RPM’s. Also be sure to also add a PID to the flywheel so it is more accurate.

Good luck in these changes, and be sure to use the search feature on the forums if you have another question before posting!

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Do you still have an overheating issue with 5500? That seems a little fast as you could run between 3000 and 4200 and get good results.

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To answer the question asked: don’t overload them, and if you do, don’t do it for long periods of time. You are violating both of these rules.

Any decent bot can score well with a single 3k rpm flywheel.

None of the wheels in the kit have good enough balance to run at that rpm w/o deforming, losing balance, wobbling, and causing power to increase to unsustainable levels. Most of the wheels can barely go past 3k w/o balance issues.

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maybe,
but just a little

How about I disregard all this math I can’t read and just give you a heart?

It doesn’t overheat for a good 5 minutes, which may be a little short, but good enough for competitions. We actually just run it at 2000-4000 rpms, we are using a 5500 rpm gearing because we didn’t want to modify our gearbox too much to run at 4200 rpms(We would have to rebuild our entire gearbox). It’s kinda buried in our robot. Also to WizardRobot33’s, we are using 200 rpm carts. So 84/12, connected to 84/12 or a 1:7:7 or 1:49

You are not making a flywheel.YOU ARE MAKING A DISC CANNON!

XD

P=Tw, T is torque and w is speed.It means that the fast your flywheel run, the lower the torque you have.Torque is the source of your flywheel’s speed.The lower torque you have, the longer your flywheel took to reach desired speed.

I think 3k rpm are suitable for most of us.We are even lower, only 1.8k rpm from the corner of the field to the opposite corner of the field.

we only use green cartiges.

Green cartiges?Are you kidding me?What’s your ratio?9800 RPM flywheel is unbelivable, and a 9800 RPM flywheel made by green cartiges is much more unbelivable.

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Can you please send a picture of this flywheel. I really, really want to see it.

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You can still make a 3000 rpm flywheel with just 200 rpm motors. Use the same gear system but switch the 84 teeth gears with a 36 tooth and a 60 tooth gear. So have the motor driving a 60-teeth with the 12 teeth being driven, on the same shaft have a 36-tooth gear connected to a 12 tooth which is driving your flywheel. That is a 15:1 ratio so it’s 3000 rpm.

9800?!?!? Green Motors?!?!? this has to be a troll.

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Ah ok. Slight modification to the math then

You would have to be using a 84:12 and an 84:12.

9800/200 = 49, 49 is 7 * 7, and that is just a combination ratio of a 84:12, and then another 84:12.

I would HIGHLY recommend that you decrease this ratio, not only because it is not necessary, but also because the main reason that you are experiencing motors burning out is due to the immense friction from the extreme ratio. I would suggest, as stated previously to try a ratio of around 3000, or a 60 tooth to 12 tooth. You will find that it should be enough to launch the disc into the basket.

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once i get in class I will