Single Flywheel Gear Ratio

I am looking to build a 4 motor single flyhweel for worlds. I want to have a very fast field fire rate. As it will be primarily a field bot. However, we still need to be able to shoot full court. What gear ratio and wherl config do you think would work best? Thank you.

My team was successful with 25:1. It easily does full court if you get the compression right with motor power between 70-80.

Common ratios are 35:1 @ 100 RPM, 25:1 @ 100 RPM. I have also seen 25:1 @ 160 RPM.

You can get most of the common gear ratios with a little less friction if you shorten the compound ratio and use turbo motors. I’m enjoying turbo motors (240 RPM) with a 1:15 ratio, it shoots full court at 55 power, (down to 50 and up to 65 depending on battery level) (Also it failed at our most recent competition because of compression issues) But really, it seems to be that the nearly any ratio can be made to work really well with enough time and effort.

well your friends at 1115 and know a lot about those just saying.

we are rebuilding and are using a 28:1, we think it will work fine but we will have to test and see

I’m rebuilding with either a 1:25 or 1:28 ratio. 1:35 is too much stress ( works, but draws lots of current on start up and much more mass can’t be added) for my heavy flywheel with 6 motors even greased and lined up right. I’d stay at max around 1:36 (1:15 with turbo) unless you are using 4" wheels on a single flywheel.

1:28 will always work :slight_smile:

Will 1:28 with 2 or 3 four inch wheels be able to reach full court? Will it have enough overhead to have some form of speed control?

My team uses a 25:1 Ratio on a 5 inch wheel. At our last tournament we used 6 motors and ended up having huge problems with ball compression until the very last match we were in. Could anyone that can shoot full court at low power levels PM me? Our team is struggling with compression and we currently can only shoot full court at max power with a 8.4V or above battery.

You might want to re-visit 8059A reveal thread… we have been using 1:28 ratio on a 5 in wheel (ok… we used 2 wheels as well).
It has always been doing well.

What’s the motor setting you are using? And… are you using any form of velocity control?

It definitely sounds like problem with the compression. Six motors have more than enough power, but at 25:1 ratio you need to run single flywheel at almost full speed even with well tuned compression and energy transfer.

I would suggest increasing gear ratio to at least 28:1 or, even better, to somewhere around 32:1 and work on tuning your compression.

Some teams could even pull off crazy good results with 40:1 and only 4 motors but they go quite a few extra miles to make it work.

In general, if you could reduce friction to the minimum and have enough patience to accurately tune the PID then you could go with higher gear ratio, like 323Z with 40:1.

However, if you need to get something ready for the competition quickly and don’t have a lot of experience with PID, then

How do you make a 1:28 gear ratio? As far as I know, VEX doesn’t make 48 tooth gears, and you would need one to have that ratio. 7 to 1(84:12 and then 4 to 1(48:12). I could be wrong though. If VEX does make those gears, can someone please post the link.

60:12 then 84:36 with turbo internal

Oh, thx, but I’ve heard that turbo motors stall a lot, so is there a better way to do it with regular motors or high speed. I currently have a single flywheel with a 3:49 speed ratio with high speed motors and it only shoots around 5 feet at full speed. I was trying to figure out why.

That shouldn’t happen, check your compression. Reduce it if it’s above.5 in

My compression is actually right around .45 inches or so.

Something is wrong there. Could you post a picture?

We used turbo motor with an overall ratio of 1:28.
And we never have any stalling problem.
Your compression looks ok. You might want to check on your friction instead.

The reason turbo motors are said to stall more is that they are geared up. You may have heard this about drive motors which, when using turbo motors on 4" wheels, may stall more than standard motors. When cleanly built, I’ve seen 25:1 gear ratios ( 60:12 x 60:12 or 5:1 x 5:1) work well on normal torque motors. Also, you should note that most of these gear ratios or used with 5" wheels. If you post a picture of you flywheel it may be easier to help you.