Photos of the NH-80 in flight from the OEM raised a question as to the AOA that the rotor was running at, which in turn impacts the hysteresis in CL, CM, CD on the blade and the subsequent SR of loads in the rotor head. Nothing that another few feet of blade span or increased Cl wouldn't sort out. The question became more interesting when looking at the location of erosion damage on the blades, it is quite unusual, and is a maintenance factor in keeping the blender happy. Fixable, sure, but there is little interest from the OEM or operators in fixing the machine. It is impractical to add half a dozen feet of the blade to the system, gets pretty noisy around the tail but only for a fraction of a second. Two choppers and a tilt-rotor cry out for some help the NH90, the PAH Tiger, and the V/MV-22. It's not rocket science, JC Lin worked the graphs 30+ years ago, but the operators remain with the mediocrity of a rotor system that defies rational explanation. Rotors dynamically pitch rapidly, that's just what they do, so all of the optimizations of worrying over an 0012 or an Onera OA-209 section or an SC-1094, VR-7, RC-04 etc is borderline vacuous, once the blade starts spinning, it has massive hysteresis which looks more like a P crossed with an italic D for CL and CM, and all of the worry that goes into getting the Cm just right, such as reflexed camber lines, well the Cm gets to look like an upside-down and mirror-reversed big L. both lift and drag are adversely affected, but al least it is only biggly, and the Cm messes with everything connected to the spinning stuff at the top. Getting rid of the Cm is in the words of the HH-3/SK61 TP: "spooky".
The rotor designs do benefit from tip sweep, BERP etc but the majority of the blade is just adding pain to the exercise, and that is needless.
