[Chris Fultz]

This will be a non-specific answer, but will get you started.

I would use both of the window motors. They are OK on power, but they have a thermal lock out (safety feature) that can cause them to stop if they get hot. You dont want that to happen in a match.

You can get an adapter and mount a sprocket to the motor, mount the motor to your "tower" system, and then mount a larger sprocket to the arm itself. Add a chain from the motor sprocket to the arm sprocket.

Use the JVN calcluator tool if you can, to get the right combination of torque and speed. The arm rotation speed will be relatively slow compared to what the motor RPM output will be so you cannot do a direct couple to the arm.

We did something similar to this is 2007. I will get a picture today and post our arrangement.