Wow, I tell you what , I really don't know! I'm just an engineering type , I
haven't thought of changing pitch on one rotor, thats got to be too simple
to be real. When I saw a picture of that system , i thought of the guts out
of a diff head (car) and how would you change the torque to one or the
other rotors without using an old automatic type brake system. I wonder
which would be harder to build?
Have a look at Dave Jackson's sites, He's been able to answer all my Q's so
far.
How has that Nolans brothers coaxial going?

Ps thats not Dennis from our forum is it?
Cheers Cam