[i]Coaxial rotors[/i] or [i]coax rotors[/i] are a pair of [[helicopter]] rotors mounted one above the other on concentric shafts, with the same axis of rotation, but turning in opposite directions (contra-rotating).

h4. See also

* [[Contra-rotating propellers]]

h4. External links

* "Wikipedia - Coaxial rotors":[https://en.wikipedia.org/wiki/Coaxial_rotors]
coaxial rotors