Originally Posted by
IFMU
The X2 TD was better at 250kts than a UH60 in cruise. I can't comment on its progeny.
I don't have the exact numbers immediately to hand but IIRC, in the entire X2 TD program the total time at 250 knots was only a few minutes. It is interesting the FAI offered Sikorsky the opportunity to take the world helicopter speed record (wingless compounds are classed as helicopters) which involves flying along over a measured course, doing a 180 and then flying the same course in the opposite direction (to account for the effect of wind) and taking the average of the two runs. This would be quite a feather in X2 technology's cap and would give great bragging rights for the technology. However, Sikorsky turned them down.