Originally Posted by
IFMU
The X2 TD was better at 250kts than a UH60 in cruise. I can't comment on its progeny.
The vibration in the X2 was brutal. That's why they had active vibration suppression for a single seater where the only goal is to not kill the pilot (all surviving test pilots will say it was great and ready for production no matter how bad it is). Relative to the UH-60, not a good example. It carries vibration suppression devices to make 130+ knots. On the S-97 you could tell from crew comments they were reluctant to go above 190 knots due to vibration as engineers worked to get it tolerable enough so they good dash to their max speed of 230 knots.