Gear box for Single flywheel help

Anyone suggest a way I can make a gear box for a Single flywheel for the nothing but net comperition? I’m brand new to this stuff And would like some suggestions, thanks!
lso, our current robot is a catapult-bot, but we (my team, 7589B) wants to make a robot with a single flywheel.

On one of my previous design I had a four motor 35:1 ratio. This gave us abilities to score from the starting tile as well as up close. This ratio is pretty simple and is created by using an 84 tooth gear that is power by four standard motors, which meshes with a 12 tooth gear that shares a driveshaft with a 60 tooth gear. The 60 tooth gear then connects with another 12 tooth gear, which creates a 35:1 ratio.

What @The Tenth suggests will work, however you do not need a gear ratio that high, even with torque motors. If you use torque motors, I would suggest a 25:1 gear ratio. If you use high speed, I would use a 21:1 gear ratio. If you use turbo motors, I would use the same gear ratio as 8059A, 11 2/3:1. All of these gear ratios would work for shooting full court shots. Honestly, you are better off trying off and prototyping flywheels with different gear ratios rather than trying to find the “right answer.” Taking a look at some gear ratio threads would be a good start if you are new to gear ratios for flywheels. When building your first flywheel, you will most likely have stalling problems at first due to build quality. I suggest you just try building a flywheel rather than spending too much time on the concept. My team found that only after failing a few times, you will make a working and effective flywheel. Even if you spend a lot of time designing a flywheel, you will likely spend the same time failing as you would if you did not plan as much. Here are a few tips that I wish I knew when I first started building our flywheel.

  1. Leave about one or two washers of space on a shaft so nothing is tightly packed (gears and spacers) and causes friction.

  2. Try to not put a shaft through 2-3 bearing flats as if bearing flats are not perfectly aligned, they will cause extra friction and will cause your flywheel to stall and have poor performance.

  3. Find the optimal compression after building the flywheel. The optimal compression will result in the ball being launched the farthest distance. Having a lot of compression will give you high recovery rates and waste potential of your flywheel.

  4. If you must use shaft collars, DO NOT have them touch metal. You never want metal against metal on your flywheel. If you must use it, put a spacer first and then a shaft collar as a spacer creates less friction than a shaft collar.

  5. If you use washers, use plastic ones as they create less friction than metal washers.

  6. After finishing each stage of the gear box, check to see if the spacers spin with ease. If they do not, add empty space equaling about one or two washers.

  7. If you use shaft collars, make sure you do not tighten them against the spacer. Once again leave about a washer of space before tightening it.

  8. Use standoffs or c-channels to keep your gear box’s structure.

Sorry, these are all the tips I have time for right now. Good luck building your flywheel, if you have any questions, feel free to ask me. If anything is unclear, just ask and I will elaborate. I hope these tips help! :slight_smile:

Along the general idea of this thread, what is the best gear box for a single flywheel shooting from the pipe?

Thanks guys! Im going to keep prototyping, I will try to post videos on this thread. Currently we have the “normal” motors. :slight_smile: keep this thread going! :smiley:

Well I would guess something like 15:1 with a 4" wheel or 9:1 with a 5" wheel. Both of these ratios are high enough that a decent recovery program such as bang bang or PID can really help the recovery rate, but not so high that oscillation decreases accuracy. For bar shots with a 5" wheel, you might honestly be able to get away with 8:1 (high speed and 5:1 external) or even 7:1, but it’s probably best to also be able to do three fourths court shooting in case the opposing alliance decided to park in front of your goal for the entire match.

In any case, there is always a way to make lower gear ratios, lighter/heavier wheels, and better hoods work, but this is a guideline from my personal experience.

@InfinityMinus1 Im actually extremly new to this (middle school) what is bang bang, or PID? Thanks!

On another one of my previous designs I used a 9:1 ratio on turbo motors. This ration was created from a 36 tooth geared powered by two motors connecting with a 1 tooth gear, and a 36 tooth gear on that same driveshaft that connects to another 1 tooth. This ratio powered by two motors had a .5 seconds spin up rate without any velocity control programs.

Essentially, these are velocity control loops. Usually, you would assign a motor a specific speed to run at, however the motor usually doesn’t output this exact speed. Everything depends on the battery. A velocity control loop involves using sensors to measure the actual speed of a motor or the actual speed of the flywheel, and having the program essentially “autotune” the speed of the motors to reach the exact speed (RPM) you want. Proportional Integral Derivative (PID) is usually the most fast and accurate of the velocity controls, but some people have found Take Back Half (TBH) to be just as effective. Bang bang, is probably the fastest but least accurate, but have been proven to be extremely effective for bar shots.

Take a look at some of these threads.

Easy PID:
Bang Bang:

Sorry about the earlier post, I was not aware you wanted to build a flywheel primarily for barshots. :slight_smile: If you have any questions, I will be happy to help.

Also, Since we can only do bar shots currently, we are afraid that in the state competition we’ll be in in like a month, that strategic teams will block us, which happened in our fist competition. Which is why my team is planning to make a robot that can consistently switch between mid field goals, bar goals, and full field goals, which I’ve found that the single flywheel can do all of these things. While scrolling along on youtube I found this gearbox that had like a 1:21 gear ratio, I would Like to know how we could possibly program the robot. Also we only have the “normal” motirs.

You could easily get short of mid coart shots with a 7:1 turbo flywheel, on our B team we did this and it shoots 4 balls in less than 2 seconds up close with no recovery code.