Tennis Ball launcher motor selction...

Using Arduino Project Guidance
#1

Hi there, I'm planning of making a tennis ball launcher original link --> http://arduino.cc/forum/index.php/topic,110827.msg858362.html#msg858362

im having trouble as to how powerful should the motors be? hi speed? hi torque?

i found this motor on ebay...will it do? --> http://www.ebay.ca/itm/RS-550PH-Motor-12V-DC-14-100-RPM-High-Power-550-Size-DC-Motor-Nichibo-/270971721651?pt=LH_DefaultDomain_0&hash=item3f172c57b3

Full load (maximum efficiency @ 12VDC) performance characteristics: Speed: 14,100 RPM Current: 7.75 A Torque: 500 g-cm (49.0 mN-m) Power output: 72.3 Watts Stall torque: 4400 g-cm (432 mN-m) Stall current: 60 A

any help would be greatly appreciated. thanks in advance. SN

#2

im having trouble as to how powerful should the motors be? hi speed? hi torque?

How will the motor actually launch the tennis ball? Trebuche style? Or like a pitching machine? How fast should the tennis ball be launched?

Picking a motor is a small part of designing a tennis ball launcher. It needs to work with the rest of the design.

#3