Originally Posted by
IFMU
I've never heard the Raider in person. I've spent a lot of time with the X2. The first time Kevin pulled pitch it got very quiet in the TM trailer. All of us looked up from our screens to see what happened. All the data said it was running but the noise went away. Those blades are magic. During the early no prop flights all you could hear outside was the S76 chase. I do not believe that video is doctored.
Excellent job S97 team!
There's nothing "magic" about the rotors. I've been very near an H-53E on takeoff and "heard" it make almost no sound, yet on other days during rotor engagement one would have a difficult time speaking to a person right next to them. The effect of relative wind on the acoustic signature is far more likely the factor in rotor noise. Also, at least when X2 was flying, the -76 was generally positioned closer to the TM van than the test article (to the best of my recollection).