Flywheel too tense

It seems to us like our flywheel is too tense in terms of gear ratio. The small gear is 12 studs and the bigger one is 36 studs. This is with a blue motor. We saw other flywheels work this way so now we are confused. Is there something we may be missing?

You should refer to your gear ratio as 36:12 (teeth). Do you mean that your flywheel has too much friction? Or are you saying it is too slow? 36:12 is only going to give you 60*36/12 = 1800 RPM, which is below the average speed (somewhere between 3000-4200 RPM). I’m going to need more context/info to help you out.


There are two 36:12 teeth gear ratios, making the speed above average. Also the wheel is not moving at all (only really a millimeter of movement from the small distance between gears) and I think the picture did not attach so I will make sure to send that here.

Thank you for clarifying that. I should add that this would make your speed 600x(36/12)x(36/12) = 600x3x3 = 5400 RPM, which is actually unnecessarily fast, and wouldn’t help you anymore than a 4200 RPM flywheel, especially because of the quick burnout from using only one motor. It is possible that there is too much weight on the motor for such a high gear ratio. Have you tested to see if the motor spins properly on its own?


We will make sure to test a lower gearing ratio, thank you. Also the motor itself is moving fine

If my math is correct, that would be way above 4200 rpm, which would mean that the flywheel would be very fast and not have enough torque to get up to speed. With a 600 rpm cart I would recommend either 60:12 or 84:12 to get the right balance of speed and torque, similar to what team 30809s said above.

Makes sense, I guess we saw this one forum talking about this exact design and we made it. Unfortunately we did not think about this just being a impossible theory and maybe no one has done it simply because it is not possible… Thank you!

1 Like

If you can spare it and want a 7:1 or 5:1 ratio, I’d recommend using two motors on your flywheel so it takes longer to burn out, if necessary.


Will it burn out if it is not always spinning with a 7:1 ratio? As in, we hold/press a button to spin it.

I haven’t tested using only one motor and 7:1 ratio, however I’d suspect that it might last longer enough. I’d recommend you test this and see-- it’s great for your engineering notebook. One piece of advice I’d give you is to possibly create a toggle for your flywheel, unless that is what you plan to do. (I took it as the flywheel would only spin which the button is being pressed.) However the motor can only begin to temporarily burn out as a result of intense use for long periods of time. If you are concerned about damaging a motor just remember to watch the temp level.

Thank you very much, we will be sure to consider that!

from what ive found the majority of the strain on the motor comes from spinning up/ stopping, so it might be beneficial to spin up to speed then keep it at that speed, if you have a small amount of friction you should be able to keep it spinning all match


7:1 wont turn for us now…

I’m currently testing one right now works ok I think for mine it i not getting up to full speed because of friction but it can send disk about half way across the field