U.S. Centennial of Flight Commission home page
Almost thirty years after building his first helicopter, Louis Bréguet designed and built this coaxial machine, which marked a

Almost thirty years after building his first helicopter, Louis Bréguet designed and built this coaxial machine, which marked a milestone in vertical flight progress. It held all world helicopter records for that period, but development was prevented by the oncoming World War II.  

Credits - Hiller Aviation Museum