Hunt3r,
The advantage of ABC is that you get the benefit across the full speed range. Sikorsky/Schweizer spent a lot of time optimising the blade section/twist/span for the performance saught. Stick on wings just were not required to get the cruise/dash performance.
Dave,
I know that the original X2 design studies used the then available non-coaxial codes, and that wake contraction will affect the results for the lower rotor. However, in forward flight i don't imagine there to be much difference between coaxial or intermeshing. In hover there probably are some advantages to the lateral symmetry of intermeshing. The down side of intermeshing is tip clearance, which might have affected operational considerations.
When i (finally) get my physics degree out of the way next october, i'll pick up my rotor simulation tool again. I'd like to adapt it to handle ABC type of configs. It would be interesting to do a design study comparison of optimised coaxial vs intermeshing vs interleaving. Finally take some of that speculation out of our discussions.
