I am learning a great deal from this exercise! Nick, serious thanks for sharing your knowledge and experience. That Comanche control system looks, at first glance, like a pretty complex program. I was suprised not to see Chuck Keys on the patent (knowledgeable chap). Will read more thoroughly this weekend.
Here is my understanding of what is happening. Looking up the NACA 0012 section in Abbot & Doenhoff, shows that the Cd vs Cl curve has a tangent to the origin at about 0.8 Cl for standard roughness. This corresponds to 8 deg AOA, which is where stall begins. This means that, having no camber, this section offers best lift/drag at high angle of attack, just before stall. For a helicopter this means running the blade at pitch just on the verge of stall requires the least power (Cp/Sigma).
The problem in a conventional helicopter is that the retreating side blade suffers reduced airspeed. If the blade is near stall in hover it will be stalled at speed, so a lower pitch is required for hover. This means a lower than ideal 0.125 Ct/Sigma for hover, so more hover power. This can be offset by beeping down Nr in hover, like S76A. The advancing side will be at an even less optimal AOA, placing additional requirements on cruise power (made worse by Glauert-Prandtle compressibility equation).
In a counterrotator the retreating blade can be unloaded, since advancing regions balance roll torque. This means that the retreating blade no longer constrains hovering blade to Ct/Sigma < 0.125. The ideal for power is if the advancing blade maintains the same pitch, hence airspeed, across the heli speed range. For this reason a counterotator works best by beeping down Nr with speed. Clearly this is limited by acceptable root stresses that the lower centripetal force, hence centrifugal acceleration, will cause. In practice this means that the advancing side will be below optimum AOA, but less so than the conventional.
Practical upshot is X2 should be more efficient in hover and at speed than conventional. So the answer to your question, Hotzenplotz, is: "because they need development"...
Marks out of 10? (Bet i don't remember any of this in the R22 next w/end).
Mart
Note: Laminar flow sections like 63-015 (R22) have low Cd "bucket", to extend lift/drag for better "penetration" to higher speeds. This will help figure of merit in hover, while extending high speed (ish).