AfterDawn: News

Video Daily: New Helicopter blade reduces noise to almost silence

Although not in our normal niche, this article was too interesting to pass up.

Eurocopter has created a new helicopter blade, dubbed Blue Edge, that significantly reduces noise from the rotor blades. Testing on an EC155 helicopter has seen noise reduced by 4 decibels.



Says Wired: "The technologies are able to reduce noise by minimizing the blade-vortex interaction of the main rotor on a helicopter. Blade-vortex interaction is the source of the pulsating sound most of us are familiar with when helicopters fly overhead. The noise is created when a rotor blade hits the wake vortex left behind from the blade in front of it."





Written by: Andre Yoskowitz @ 26 Feb 2010 22:12

• Previous article

• Baidu's Qiyi gets $50 million in investments

• Next article

• Twitter warns of phishing scam, two days late

• 9 comments

• KSib

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

  26.2.2010 22:24 #1

• B33rdrnkr

  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....

  26.2.2010 23:01 #2

• ddp

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

  26.2.2010 23:12 #3

• llongtheD

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

  26.2.2010 23:19 #4

• Pop_Smith

  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.

  26.2.2010 23:20 #5

• jony218

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

  27.2.2010 01:30 #6

• DXR88

  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.

  27.2.2010 18:06 #7

• SoulGLOW

  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.

  27.2.2010 20:43 #8

• djgizmo

  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.

  27.2.2010 23:13 #9