Help with Launcher

[jeremy5561]

I'm using wheels for the ball launcher I'm building. This is my first year and I'm not sure how to do it. My teammates suggested that I use am-0914 but 75 RPM is too slow, and if hooked directly to the 15cm diameter wheels, would launch at only about 2 km/h.

We've already reached the maximum 4 CIM motors so I'm wondering if am-0912 motor will do the job. I would attach it to the CIM-sim gearbox and then attach it to this sprocket. A chain and another sprocket will connect to the 6" wheel that came in our kit. Will there be enough torque? since I can only use two of those andymark motors, can I mix an andymark motor and a fisherprice motor and put them onto the cimsim? Is there a better solution?.

I don't know how to do torque but I read it from the Internet. The gearbox will increase the torque of each motor to 2.14 Nm. With a wheel of 0.075 radius, that means the force out of the wheel is 28.5 N. Assuming that the load cuts the motor speed into 1/4 of it's free speed, that leaves 4000 RPM reduced to 800 RPM by the gearbox. 800 RPM is 13.33 RPS. The 15 cm diameter wheel has circumference 0.47 m. 0.47m*13.3 gives me a speed of about 6 m/s or 22.5 km/h. Will this work?