Mart,
I apologize for the curtness of the preceding post, but I'm not in a position to say anything more.
However, while looking to see if the English version of the book had been published I did stumble across
Open Airscrew VTOL Concepts (232 page 'pdf' file) by Stepniewski and Tarczynski in 1992. It does not appear to include twin-rotor craft but it does look like an interesting evaluation of a large number of other rotorcraft configurations. I've downloaded the file and plan to read it in the near future.
Another excellent overview of the coaxial configuration is
A Survey of Theoretical and Experimental Coaxial Rotor Aerodynamic Research.
Dave
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Edited to respond to your last post.
"Direction of rotation differs from all other intermeshing helicopters."
Inboard advance offers aero and gyro roll/yaw stability, outboard advance offers better aero efficiency...
Flettner is the only person, to my knowledge, who ever tested the 'outside forward' rotation. I believe that your answer is correct, and in addition, there is a pitch-torque coupling to be considered.
These disadvantages will be reduced due to the smaller 'V' angle allowed by 'absolutly' rigid rotors.
"Static Stability might be affected by anhedral, resulting from the slope of the advancing blades. ???:"
Rotation direction will adversely affect stability, but a nice gyro stability aumented control system will make it and flyable...
Agreed, however I would like to look for a 'natural' solution, such as the smaller 'V' angle, before having to consider the weight, complexity and reliability of an add-on.
Remember the jury is still out on the Intermesher Vs Coaxial debate...
Not for this kid.
I've sat on the jury (and on the fence) long enough to know where the grass is greener.
This thread and the above two links are a microcosm of your court case. It is a case of too few having the motivation to consider the
Intermeshing configuration.
Flettner had it right. Kellett sensed the possibilities. Kaman took it in the wrong direction. And Stepniewski saw the greener grass, one year before he was placed six feet under it.
Edited to change 'Interleaving' to 'Intermeshing' ~ after Graviman's following post.