Tail rotors in general? Fenestron tail rotors function the same as traditional tail rotors. only that they are housed inside a shroud and have more fan blades. NOTAR is the same as the other above listed two as in the sense they both use torque effect (spinning motion of the main rotors) to produce yaw. Different rotor configurations use different methods for yaw control, some interesting... like the CH-47, it tilts the two tandum rotors opposite of each other, turning the body of the Helo.