Damn! It has been thought of. There goes my patent :-)
Maybe the control systems weren't refined enough at the time? Though I doubt that, to be honest. Maybe it was just a focus on one thing (driving the rotors 'torque free') to the exclusion of alternatives? (Never been guilty of that myself, ever :-) ) Just a little strange that someone on the team didn't think, when assaulted by the noise, "how's about we....?"
(edit) Just seen heli1's post. Probably on the money there.
Last edited by Robbo Jock; 30th Jun 2013 at 21:40.