Jetcopter Speed up gear
as for the rotor head, my point was, stress wise, whats really the diverence between 1400 rpm with +- 12 degrees pitch, or 1200 rpm with 18 degrees pitch as is claimed for the NH90 with HP5 ?
its just a diferent part of the rotor head you are stressing ... with higher head speed, its the spindle bolts that take more stress as well as the thrust bearings and blade bolts, with the 18degrees pitch, id say thats wher the rotor grips take some more stress, as well as the linkages and entire controll system (swash plate, etc .. )
I do have to say its impresive how much stress our helis hold up to these days .... hey, look at the 90 sized 3d machines !! i think they put a lot more stress on the rotorheads than most turbine helis ...
Wojtek