This calculator finds the airgap of a brushless outrunner-motor based on the
size of motor together with magnet width and thickness. Just enter your data and
compute. Negative number means you have too thick magnets. An airgap of 0.1mm
will give high torque, while less would be inconvenient.
(You can enter data
in any measure you like, as long as you use same on all
fields.)
KreAture