Oelimichen No.1

Etienne Oemichen, a young engineer with the Peugeot motor car company, began to experiment with rotating-wing designs in 1920, and in all designed and built six different vertical take-off machines. When the first of these failed to develop enough lift from its twin rotors and 25hp engine to rise off the ground, he added a hydrogen-filled balloon on top of it to give it added stability and lift.