To:cpt
The reason I have been given is and also read somewhere in a book (if I remember well, written by Patrick Boulet, a french helicopter test pilot) is the one that Nick Lappos has already given; it comes from one of the transmission gear of that WW2 german twin rotor helicopter(FW220...?).
As Nick had indicated the French took the rear rotor and transmission from a helicopter that had two rotors and two transmissions both of which turned in opposite directions.
Since they had their choice do you think that the greatest influence governing their choice is the engine that would power this rear rotor turned in the opposite direction from an American engine.
Not knowing the construction of the rear transmission I can only assume that the input gear sets were designed to turn in the direction that powered the rear transmission and they were opposite from the front gear box.
