Silent rotorblades
 

Hello everyone,I'm new here and I'm not a pilot,but have been working for an AG pilot cropdusting.I was the truck driver until he crashed it a couple weeks ago.I would also like to ask you pilots some questions regarding when you should just not fly the helicopter because of mechanical issues.
Before that though,I came across these blades,are they going to become the norm. or just some engineers dream?
Most Viewed - Google Fast Flip
Video: A Silent Rotor Blade Paves the Way for Super-Stealth Choppers | Popular Science

Welcome, Jim.

If they make the blades that quiet, in UK our governing body, the CAA, will make us fit bullhorns to warn the pedestrians! :ok:

Pretty impressive ,The first time I heard the EC145 fly in I was amazed how quiet it was. They will now need to put silencers on the engines as they will soon become the major source of noise.

Cool!

Is there any risk that blade strength is compromised by the angular shape?

That's incredible. I bet the price tag is worthy of cardiac arrest.

John R81,

Knowing how EC(D) blades are made (a good trip if you can get one) I would doubt that there would be much loss of integrity at that end of the blade. The shaped tip may not even contain a void, as does the rest of the blade, and that may add momentum and stiffen it up greatly. Pure guesswork though!

From what I have seen,ANYTHING associated with helicopters is worthy of cardiac arrest.I guess we'll see if these blades become standard for noise abatement.I like the noise the helicopters make now,but then I don't have to sit in it all day long either.Just like the jake brakes on a semi truck,some people love the racket they make,I wish that sound would go away after being on the road for a couple of weeks.

The original quiet helicopter.
 

Hughes Helicopters carried out a lot of work on their OH-6A/Hughes 500 many years ago to produce a quiet helicopter.

Air America's Black Helicopter | Military Aviation | Air & Space Magazine

Apparently, the noise reduction was as high as 20 decibels in certain phases of flight. The main blade tips were trapezoidal in shape and the four-blade tail rotor turned at a lower rpm. Those who worked on it swear that it was quieter than any of the quietest of today's helicopters. It must have been very quiet indeed.

Would the "Quiet One" fitted with a NOTAR system be even quieter, especially if the NOTAR fan blades were "shaped" to produce even less sound?

500 Fan.