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Originally Posted by aldaron327
There's one thing that would make a "stealth helicopter" stick out on radar that they can't fix: Rotor blades turning at hundreds of RPM. Those blades turning really stand out on radar.
Also, I'm not sure how much noise mitigation they've come up with over the years but from personal experience, a person can hear a helicopter coming from pretty far out depending on wind direction/velocity, altitude of the aircraft, etc.
Still, it's a cool concept... I just don't think that the physics of how a helicopter flies supports it.
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That's exactly what they are talking about. It's not just the material it's made with. It's the functionality. Take in mind, the story said, the helicopter "grazed" the compound and it took them getting that close to be detected. (If indeed it was shot down by enemy forces).
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The stricken aircraft, which commandos blew up at the scene, appears to be a long-rumored stealth helicopter, NBC News reported; a Black Hawk modified to reduce rotor noise and make it more difficult to detect by radar.
Pentagon officials have declined to comment.
Aviation Week reported that the chopper's tail appears to be highly modified compared to a standard H-60 Black Hawk. The report noted that stealth features on a helicopter usually aim to dampen rotor noise and reduce infrared signals.
Noise reduction can be accomplished by adding blades to the rotors and changing the way the pilot flies the chopper, such as flying in a manner to reduce the rotor's rpm, the report said.
As for reducing the likelihood of the aircraft chopper giving off infrared signals, Aviation Week pointed to an earlier helicopter prototype that had a complex exhaust system and fresh air ejectors to lessen the aircraft's heat signals
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http://www.msnbc.msn.com/id/42912904...h_of_bin_laden