A coaxial helicopter, comprising a first rotor carried by a first shaft and a
second
rotor carried by a second shaft; wherein one of the first and second rotors has
cyclic pitch control and the other rotor does not have cyclic pitch control, at
least pitch and roll control being implemented by cyclic blade pitch control of
only one rotor of the coaxial rotor set. Provisions for yaw control can include
differential collective control of the first and second rotors, providing yaw paddles
and/or a tail rotor, ducted fan, or an air jet configured for yawing the coaxial helicopter.
