Check out our 2012 ball launcher / shooter:
http://youtu.be/DO0XzkthMUs?hd=1
The purpose of this particular launcher was to try different configurations and parameters such as wheel rpm, wheel spacing and wheel width. We also wanted to be able to adjust these configurations precisely and quickly. Over the next few days we will be trying various wheel configurations and materials to improve launch distance and consistency.
We believe this exact design could serve as a final shooter with the correct control parameters and motor selection but there is obviously a fair amount of structural / mechanical optimization that could take place.
/edit With Tech Specs
Tech Specs:
Wheels: 6" FRC 2008 KOP wheels
Motors: 2x CIM
Gear Used: 14 tooth to 40 tooth 1 stage
Center To Center Wheel Spacing: 12" ( creates 6" opening )
Distance between wheels: 3.625" insides
We are all on a big team named FIRST - Al Skierkiewicz [more] 
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