Relationship between wheel type and power
 

While doing some testing with a prototype ball shooter we have come onto the important question of wheel size/width/type.

I believe that the bigger diameter of the wheel (6, 8 in) the faster it will be moving with more power at the edge.
Could someone please explain why this is so?

On another note...
What kind of influence does the surface area of the wheel have with the shooting?

Also how would the amount of grip the wheel provides influence the shot?

Re: Relationship between wheel type and power
 

with the same rpm (same drive motor/gears) the edge of a large wheel has a faster surface velocity than a smaller wheel.

Power is not as straightforward. A larger wheel has higher speed but less torque. Technically the power is the same - the power is the amount of power your motor is putting into the wheel. If you connect a 1 HP motor, then you have one HP available.

energy is what you really need to look at. At the same RPM a heavier or larger diameter wheel will have more rotational intertia (energy) than a smaller one. When a ball comes in contact with the wheel, a larger one will have more stored energy to transfer.

Re: Relationship between wheel type and power
 

Right, but the tradeoff is spoolup time. You need to realize that a wheel with a greater power storage capability will also have a greater inertial moment, and therefore require more time to get it up to speed than a smaller flywheel. That makes sense. Now, Ken's right, the reason why a bigger wheel throws the ball harder is about it's linear speed. That means the amount of wheel that passes past a reference point on the wheel in a given amount of time.

Linear velocity (to get more, increase the RPM or the diameter of the wheel) means a greater exit velocity of the ball. Greater flywheel kinetic energy ( increase the diameter, or increase the mass), assuming an adequate power (enough that the ball doesn't really realize the flywheel slowing down during launch) will mean you can fire faster. If less KE is taken from the flywheel, you need less time to get it back up to speed for the next shot.

Re: Relationship between wheel type and power
 

My dad has a lot of experience with Ball pitchers and the heaver the wheel the more accurate, and farther the ball will go. :)