Re: Electrically Powered Helicopters

[bdube@boulder.nist.gov (Bill Dube')]

>Gliders can be extremely quiet and efficient. They have long, thin wings.
>Imagine using glider wings as helicopter blades. You get a helicopter with
>very long blades turning very slowly. Each blade is a highly efficient wing,
>flying in circles around the central bearing. I know of model helicopters
>built this way, and they do indeed fly very quietly and glide exceptionally
>well. But I don't know if it's been done for full-sized helicopters.
    
    The Reynold's number and the absolute limit on the tip speed (must be
sub-sonic) prevent scaling up.
             _   /|             
             \'o.O'              Bill Dube'
           =(___)=           bdube@boulder.nist.gov
              U