[Graham]

I've got a standard ninco Sierra rs500 that I was thinking of running. It has a nc-9 sparker motor fitted. It's rated at 20,800 rpm @ 14.8v. Will this be Class A or B? Cheers

Hi Mike,
the NC-9 motor is 16K at 12volts and has similar Torque rating to a Scalextric motor, so it can be run as a Class A.