Video Daily: New Helicopter blade reduces noise to almost silence

A helicopter could stalk you and you'd never know :)

with night vision/infrared and cameras that can see a crack in your fingernails from 15,000 feet they prolly already do now and you don't know it....

see blue thunder the movie with roy schieder. the helicopter was silent in that movie tho not in reality.

Reducing the blade noise by a mere 4 decibels, is hardly going to make the helicopter silent.

That's pretty cool, I know sound intensity doubles every 10 decibels but I'm surprised that it's only a four-decibel reduction. This sounds much closer to a 10 decibel reduction to my ears.

That is great now if they can put a muffler on the jet engine that powers the rotors it might actually prove useful.

they did this a long time ago on many Military stealth based choppers, it had a major draw backhowever, it made them to stall prone.

it was used on Comanche stealth choppers(RAH-66)in conjunction with a Fenestron tail. Fenestron was also designed by Eurocopter to be quieter.

all you need for stealth tech is a few mics and some software to then create an inverse wave form to the one the mics pick up and then pump out that sound through speakers nearby. there in both wave forms will cancel each other out.

SoulGLOW, that would normally be true... however, remember the sounds waves need to arrive at the listener / patron at the same time for it to work. If either wave arrives 1ms late, the sound is no longer canceled.

I think they do this to some extent on some of the current generation stealth choppers, however rumor has it they are being phased out from a new magnetic technology from darpa.