Helis
History of rotary wing aircraft
http://www.helis.com/timeline/sikorsky.php
Humanpoweredhelicopters
Humanpoweredhelicopters
http://www.humanpoweredhelicopters.org/sikorskyprize/index.htm
Keystonehelicopter
Keystonehelicopter
http://www.keystonehelicopter.com
Inventors
Chronicle of the evolution of rotary wing aircraft - helicopter pioneers and inventors profiled.
http://inventors.about.com/od/hstartinventions/a/helicopter.htm
Aviastar
Aviastar
http://www.aviastar.org/helicopters_eng/sikorsky.html
Sikorsky
Sikorsky
http://www.sikorsky.com/