Kamov's coaxial layout uses two counter-rotating rotor systems to cancel the torque that would otherwise spin the fuselage. With no tail rotor absorbing power, more engine output can contribute to lift and efficiency, useful qualities on a compact shipborne helicopter. The mechanism is also more complicated than a conventional rotor and tail-rotor arrangement. That tradeoff explains both the Helix's performance and why fewer designers adopt the configuration.
Notable Point · 37:30-38:20
Coaxial rotors trade tail-rotor losses for mechanical complexity
Counter-rotating rotors cancel torque and direct more power into lift, but the arrangement demands a more complicated mechanism.