Guy Alcala wrote in message ...

Noise is rather a large issue for the military, if you're trying to sneak
up on people to prevent them from shooting at you. The V-22 is much
quieter than a helo when in fixed-wing mode, which means the other side
doesn't hear you coming several minutes in advance (on the rare occasions
that a Huey flies around in the area, despite my lousy hearing I can
usually be dressed and outside my house before it comes over).

I'm not sure how much of a problem it would be in this case, as the
noise came from the tip-jets which were only lit up when the Rotodyne
was preparing to land. In level flight the rotor was just
autorotating. I don't know if this would produce any more noise than a
fixed-wing, but I suspect it would be much less than a helo.

Tony Williams
Military gun and ammunition website: http://www.quarry.nildram.co.uk
Military gun and ammunition discussion forum:
http://forums.delphiforums.com/autogun/messages/