One motor fly wheel connected to motor without cartridge

I coach a VRC middle school team. Our team 's robot has a 4 motor drive train, 1 motor for color spinner, 1 motor intake, and one motor flywheel. They currently can’t get score a disk in the goal from the autonomous line (it’s just short, hits the edge of the basket). But do pretty good closer to the goal. They want to fix the flywheel to be able to possibly get an autonomous win point for their next competition on December 10. We just got versahub and balls bearings finally and hopefully rebuilding the flywheel using these will help. We plan to test 4 different hardness wheels and see if that matters. Hopefully we can make it work.

Our alliance partner yesterday had their single motor directly connected to their flywheel and one of my team members wants to explore whether this is a good idea. It seems like it would be less friction and simpler. Is their an explanation somewhere on how to use a motor without a cartridge? Is this likely a good idea to try? Does doing this make it so they motor can no longer be used with a cartridge?

Here is their current flywheel .

Welcome to the forum!!

You can get to the sweet spot of 2500-3200 RPM without being direct drive. The gears will work to get you to the speed to launch. The ball bearings will be a huge help, friction is never your real friend.

Grip and the launch angle are also very important.

If you are going too fast the disc will blow past the chains, so a lighter touch will be helpful.


The team has built the flywheel twice. Each time it works great initially but something must eventually get a little twisted causing more friction or something. I have to impression to get the speed we need really small changes (like something gets barely twisted in a match) keeps it from hitting the sweet spot.

Our team tested the angle and ended with one that’s pretty steep and works best probably from just outside the low goal. We do plan to completely rebuild this after the December competition to make our intake shorter.

if you’re interesting in pursuing a cartridgeless motor, this topic has a lot of good discussion on the methods

of course, this is not an easy way around friction problems, and it can cause some issues with vibrations if the connection between internal motor gear and shaft isn’t done well.


Our team has completed in four tournaments using this custom cartridge made from cnc cut polycarbonate and an insert. It has served us well, however, one time the flywheel ran into an obstacle and was suddenly stopped, which broke the cartridge and caused minor motor damage


Not enough hearts allowed for this. This is the first really engineered design I’ve seen for a direct drive. Very nice implementation.

Thanks for sharing this, I’ve noticed that teams this year have been more secretive about sharing things.


Thanks. Through the links we found a video our partner was referencing. We thought they said to look for 616x but it was 606x that did a video of a motor without a cartridge. Also appreciate the other example. We are trying to wrap our heads around these. Excited to try out some different things and see what works.


I think we first mentioned it a couple months ago in this vlog: GOLD! RoboVlog - Progress Through Failure - Vex Spin-up Ep13 - YouTube. But this was really early in the design process. I thought we revisited it in a later vlog, but I couldn’t find it. Glad we could help!


@bobbybarton3 , would you be willing to share the files for this for other students to use?

The discs are about the size of a gear cartridge and if you have a ruler you can measure the diameter of the gear👍

You don’t need to buy extra flex wheels, if that’s what you mean. In our experience, you can save money and do just as well with rubber bands covering joined wheels or flat chain pieces around the sprocket.

What is important is that you take care of the aligning your gearbox to minimize friction.

Another trick is that you can use one-time rubber band catapult (that needs no motor) for autonomous. You pull it back once before the game, secure it with the pin and then when, let say intake starts rotating, it pulls the pin and catapult will score preloads in less than a second.


We bought the flex wheels a month or so ago. We tested the each hardness with and without rubber bands and found found the medium hardness with rubber bands and the hardest one without them shot the furthest. We also added a ball bearing and support above the wheel to stop the vibrations. Now we canscore from the autonomous line.

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