Originally Posted by
Bell_ringer
may have something to do with the desire to keep the tailboom in one piece.
Not to mention the heads of anyone approaching the helo...
Noise wise, my first guess is that it would be quieter and at a higher frequency. A large amount of helicopter noise is from the blade hitting the vortex from preceding rotor - less then intensity of that vortex and you should reduce the noise. But there will be more (smaller) vorticies so the frequency would increase.