[JVN]

Some considerations that haven't been mentioned:

• The tip velocity of the shooter wheel is proportional to the wheel diameter. Larger wheel = faster tip velocity = further shot. You can't ask us for RPM without telling us your wheel diameter.

• 2 Wheels (top & bottom or right & left) will result in the ball leaving the shooter at double the velocity. (With a 1-wheel system the ball is "rolled out" of the shooter, with 2-wheels the ball is "tossed".)

• Recharge time will depend on your gear ratio. Luckily the CIM has tons of power, so you should be fine if you're gear ratios are somewhat reasonable.

• System rotational inertia will also affect recharge time and will affect how much speed the wheel loses during a shot. More inertia = less speed loss = more repeatable shot. How much mass do you have spinning? Hint: If you don't want a heavy system but still want a high rotational inertia put the mass as far out as possible (make the wheel heavy at the edge.)

• How far do you want to shoot? If you're looking for a short range shooter you might find that a lower RPM wheel will be more accurate in the ranges you want, and will result in a faster fire rate (the wheel don't need to slow down).

• We found that the compression on the ball will affect the shot distance. Experiment. We like 1.75" of compression. Your mileage may vary.

• What type of shot do you want to make? A fast ball? A lob shot? This will greatly determine how fast you need to launch the ball. What angle will your shooter be at?

Overall... the secret is PROTOTYPING! Design is an iterative process. Do some basic design in your head. Build it. Test it. Improve it. Repeat until satisfied. This is the secret to the entire 2009 game. The teams who do really well this year will be the ones who experiment a lot.

Good Luck!
-John