One hint that might help with arming - don't expect an ESC to respond to a sudden discontinuous change in command angle -
it may assume this is due to co-channel interference and simply cut-out. Ramp the servo.write () values up and down
smoothly (its also a lot safer, RC brushless motors are extremely high power - if connected to a propeller they can cut a finger
to the bone without the slightest problem - this is why an arming sequence is used and why it beeps before starting).
If the motor is spinning anything like a prop then goggles and gloves are strongly advised.