Nothing irritates me more than trying to sleep at night, only to be jolted awake by a low flying OUTRAGEOUSLY LOUD police helicopter.

As usual, the important things are left out of your articles. I have petitioned the city council of Los Angeles and the police department about their helicopters.
Usually they only come out and fly around looking for the nearest donut shop.
After waking everyone up in the neighborhood they insist on hovering over, or flying round and round with this deafening sound, they finally leave, with nothing happening.

Now if your article said that these helicopters were SILENT, wafting through the air with the greatest of ease, well then I would be greatly impressed.

Perhaps you could do a follow up story about this important ingredient in developing helicopters,
It is my best guess with the double windmills on top of this sleek new model will be making TWICE the noise of the regular helicopter.

I wish Sikorsky would develop a silent helicopter for the police and the military.
Don\'t you think that would be a great idea????

There is much too much noise in this world.

Not only fast but because it has no wasted tail rotor power it\'s more eff, carries a larger load/hp and far less likely to get damaged/crash from the tail rotor, a major cause of helicopter crashes.

Hmmm, very good, but a British Westland Lynx using a rigid rotor head and conventional tail rotor reached a whisker over 249mph (in excess of 400knots) way back in August 1986. What have Sikorsky been doing all this time? ;)

@jerryd: I imagine that pusher prop at the back end would consume a fair bit of power, especially as it is presumably used to augment main rotor thrust in straight and level flight at speed. It would also be almost as vulnerable as a conventional tail rotor when hovering in restricted spaces, woodland clearings, cliff faces etc. I can only assume there is some directional control over the prop to achieve lateral manoeuvring in the hover because, as far as I know, there is no resultant torque to \"manipulate\" with contra-rotating main rotors.
Interesting project. I wonder if they\'ll fit it with winglets to off-load the main rotors at high speed. They may as well, \'cos they are going to need somewhere to hang the mini-guns, missiles, bombs and rockets that they undoubtedly have in mind for it... :)

What ever happened to the speed records made by the Lockheed model L-286(H-51) rigid rotor demonstrator and AH-56 helicopters, they were flying more than 250 MPH in the 1960s.

@Mike:
What Jerry is talking about to is efficiency. The power consumed by the tail rotor does not add to the speed or lift. It is wasted countering the torque produced by the main rotor.
While you may damage the pusher prop, it will no longer be a major emergency due to loss of yaw control.
Controlling the yaw on a co-axial is done by differentiating the lift produced by each rotor; the collective of one goes up while the other goes down and the combined lift stays the same.
Winglets would compromise hovering performance. One of the aims of the project is to gain higher cruising speeds while maintaining hovering performance.

@luckyfella1:
When I hear a heli fly overhead at night, a flush of calm comes over me and I feel at peace in the world. Luckily for you, though, those many short blades should make it quieter.

How about having the rotor blades auto rotate like an auto-gyro. Also there could be winglets fitted that hang down for take off, and raise horizontally for forward flight.

The limiting factor for helicopter speed is the blade tip velocity reaching mach 1 as it is being driven forward. So the only way for a helicopter to go faster is to have a smaller diameter rotor, and because the lift is so much less that\'s why they need two or more rotors.

@Grunchy:
Not true. The main limiting factor is retreating blade stall. That doesn\'t matter so much when you have another rotor running the opposite direction since you now have lift from both sides.
@windykites1
Autogyros are slow. The main rotors create huge drag -- they convert forward airspeed into lift.