# Urgent help with flywheel

Hello friends,
It me David again. I need urgent help. For background info I have a single flywheel shooter with speed gears and a 25:1 external gearing. I want to know how can I make the flywheel accelerate faster. I see teams that accelerate super quickly and it takes 2-3 seconds four ours to fully accelerate after it shoots.
This is urgent because our first competition is near.
So please how can I make it accelerate a lot faster when it shoots a ball. I want to shoot a ball about every 1.5 seconds.

Many Many thanks
David

How many motors on the flywheel do you have? more motors can help this problem

1. Decrease friction by making sure structure is straight
2. Decrease friction by making sure spacing is right
3. Decrease friction by using tiny amounts of grease
4. Decrease friction by decreasing ball compression
5. Reduce the effects of friction by adding more motors

In other words, DECREASE FRICTION!

I have 4 motors powering the flywheel

what do you think the right spacing is and what kind of grease

The acceleration of your flywheel depends on the size and weight of your flywheel, and your gear ratio. In general, a smaller, lighter flywheel will accelerate faster. Also, if your gear ratio is too high, your flywheel will not have enough torque to accelerate quick enough. If your gear ratio is too small, your flywheel will have lots of torque, but not have enough speed to launch the ball far enough.

I don’t know what kind flywheel you are using, but for both a 5 inch and 4 inch wheel, your gear ratio is too high. This means that your flywheel does not have enough torque to accelerate quickly.

If you choose a 5 inch wheel as your flywheel, you would want a total gear ratio of about 1:28, which is what 8059A has. This is accomplished with turbo gears internally and then two reductions externally, 7:3 and then 5:1.

If you choose a 4 inch wheel as your flywheel, you would want a total gear ratio of about 1:35. This is accomplished with high torque (standard) gears internally and two reductions externally, 1:7 and then 1:5. I can personally vouch for this combination as having a short delay in between shots. Because the flywheel is lighter and smaller, it will also accelerate from rest more quickly. (It’s a little more complicated than that, but I won’t get into details.)

When a ball is shot from your launcher, it is squeezed in between the flywheel and a metal back plate. There needs to be friction between the ball and the backplate, otherwise the ball will slip, and some energy will be lost. I assume you’re getting this friction by squeezing the ball in between the flywheel and back plate. The ball pushes back on the back plate and causes friction between these surfaces.

However, you may be squeezing the ball too much which will cause friction between the flywheel axle and bearings. This is bad friction, as it will slow down your flywheel. So you may need to increase the distance between the flywheel and back plate. Try several different spacings less than 4 inches. Another way you can get friction between your back plate and ball (which is good friction) is by covering the back plate in high-friction material. Anti-slip mat should do well.

Hope this helps!

EDIT: The number of motors matters as well. You will most likely need 3 or 4 motors in order to shoot a ball every 1.5 seconds with a single flywheel launcher.

Spacing: If you subtract out one or two washers from the spacing you absolutely need, that helps a lot with friction.

Grease: This is more of a last resort action. Grease gets rather messy sometimes. But the grease has to be non-aerosal based, IIRC

I have a different apinion. The smaller friction between the ball and the backplate the better. Try to think this, assumming the friction is infinite, this way the ball will not flip with back plate and the ball can only spin. Thus, a lot of energy will waste for spinning the ball.
On the other hand, if friction is sero, the ball will be shot without spinning.

That’s just my opinion. Hope more can join this topic.

It’s actually the opposite; if there is zero friction the ball will spin forever, but if there is infinite friction the energy transfer would be almost perfect (assuming you weren’t compressing the ball, which is another story) and the ball would spin with perfect amounts of spin and velocity.

Of course, I could be wrong.

Its interesting that you went for a 25:1 external gear ratio. I am no expert on flywheels, but that seems pretty high to me assuming you have turbo motors. By decreasing the gear ratio to 20:1 or 15:1 (again, this might not be enough power; I am a flywheel noob), you will increase the recovery time by increasing torque to the shaft that spins the flywheel.

Another solution is, as everyone has been saying, DECREASE FRICTION in any way possible. A good test is to detach all plates and motors and spin the flywheel. Then, once you attach the plate but not the motor, spin the wheel again and see if it spins for almost the same amount of time. If not, there is excessive friction.

One last thought. If you have only one wheel on the shaft, go up to 2 and ziptie them together. This increases the weight of the assembly. That, in turn, increases the inertia of the flywheel, so that shooting a ball slows it down less. This could lead to other problems, such as the wheel not getting up to speed fast enough during auton at the beginning of the match, but it will significantly lower your recovery time.

Try playing with the parts to see what helps and what doesn’t, and good luck!

Assuming they have turbo motors seems strange when he specifically said he had high speed motors.

Ah, good point, I didn’t see that. Thank you. In that case, your gear ratio is still a bit high, but not too much so.

Good point!
if zero friction, the ball will be shot out or spinning forever.
Think it this way, if you put a ball slightly onto a flywheel, friction between ball and back plate(air) is zero, the ball will be shot out, not spining, right?
if the ball gets heavier and heavier, shooting will get harder and harder, and the ball will begin to spin.
I think this is really a balance between the inertia and weight of the ball.
what do you think?

What Jason32A said is correct. Assume no friction between the ball and backplate. The ball will simply spin in place forever and not be launched at all. However, if there is infinite friction between the ball and backplate, the ball will be launched quite well. So friction between the ball and backplate is good. Think about the ball like a tires on a car. If there is no friction between the tires and road, and you step on the gas, the wheels will spin in place and the car won’t move. However, if there is friction, the tires (and the rest of the car) will move forwards.

Switch high speed motors to turbo motors.

How do you make the turbo motors? We have the same problem with our launcher but its on one side of it. (also its setup exactly the same on each side)

You have to order the turbo gearing kits and then install them by replacing the two gears already in the motor.