Variable pitch fan, should we discount the torque resistance as a result of air flow loading on large fan blades? Seems to me propulsers could accelerate faster with a lower pitch on the blade at the compression rates RR is going for, then lay the torque on a higher pitch fan that produces most of the thrust gradually. I understand this tech has been of interest for years, more moving parts more complications. The higher compression values/lower tolerances is the big challenge in the core compressor/turbine sections.