https://www.nationaldefensemagazine....n-helo-concept
"One example is the main rotor system. That technology was first built and tested during the YUH-61 Vertol helicopter competition, he noted."
and
https://en.wikipedia.org/wiki/Boeing_Vertol_YUH-61
"While Sikorsky chose a fully articulated rotor head with elastomeric bearings, Boeing Vertol chose a rigid main rotor design, based upon technology supplied by MBB, which was partnered with Boeing Vertol at the time."
Last edited by noneofyourbusiness; 4th Mar 2020 at 13:51.